nitrophenols and Neoplasms

B-Cell Lymphoma 2 (BCL-2), c-MYC and related proteins are arguably amongst the most widely studied in all of biology. Every year there are thousands of papers reporting on different aspects of their biochemistry, cellular and physiological mechanisms and functions. This plethora of literature can be attributed to both proteins playing essential roles in the normal functioning of a cell, and by extension a whole organism, but also due to their central role in disease, most notably, cancer. Many cancers arise due to genetic lesions resulting in deregulation of both proteins, and indeed the development and survival of tumours is often dependent on co-operativity between these protein families. In this review we will discuss the individual roles of both proteins in cancer, describe cancers where co-operativity between them has been well-characterised and finally, some strategies to target these proteins therapeutically.

Topics: Aniline Compounds; Antineoplastic Agents; Apoptosis; Biphenyl Compounds; Bridged Bicyclo Compounds, Heterocyclic; Carcinogenesis; Cell Line, Tumor; Cell Survival; Clinical Trials as Topic; Gene Expression Regulation, Neoplastic; Humans; Morpholinos; Neoplasms; Nitrophenols; Peptide Fragments; Piperazines; Proto-Oncogene Proteins c-bcl-2; Proto-Oncogene Proteins c-myc; Rituximab; Signal Transduction; Sulfonamides

It is over 20 years since the first fragment-based discovery projects were disclosed. The methods are now mature for most 'conventional' targets in drug discovery such as enzymes (kinases and proteases) but there has also been growing success on more challenging targets, such as disruption of protein-protein interactions. The main application is to identify tractable chemical startpoints that non-covalently modulate the activity of a biological molecule. In this essay, we overview current practice in the methods and discuss how they have had an impact in lead discovery - generating a large number of fragment-derived compounds that are in clinical trials and two medicines treating patients. In addition, we discuss some of the more recent applications of the methods in chemical biology - providing chemical tools to investigate biological molecules, mechanisms and systems.

Topics: Biphenyl Compounds; Clinical Trials as Topic; Combinatorial Chemistry Techniques; Drug Design; Drug Discovery; Humans; Indoles; Molecular Docking Simulation; Neoplasm Proteins; Neoplasms; Nitrophenols; Piperazines; Protein Binding; Proto-Oncogene Proteins B-raf; Proto-Oncogene Proteins p21(ras); Small Molecule Libraries; Structure-Activity Relationship; Sulfonamides; Thermodynamics; Vemurafenib

Bcl-2 family members form a network of protein-protein interactions that regulate apoptosis through permeabilization of the mitochondrial outer membrane. Deciphering this intricate network requires streamlined experimental models, including the heterologous expression in yeast. This approach had previously enabled researchers to identify domains and residues that underlie the conformational changes driving the translocation, the insertion and the oligomerization of the pro-apoptotic protein Bax at the level of the mitochondrial outer membrane. Recent studies that combine experiments in yeast and in mammalian cells have shown the unexpected effect of the anti-apoptotic protein Bcl-xL on the priming of Bax. As demonstrated with the BH3-mimetic molecule ABT-737, this property of Bcl-xL, and of Bcl-2, is crucial to elaborate about how apoptosis could be reactivated in tumoral cells.

Topics: Animals; bcl-2-Associated X Protein; bcl-X Protein; Biphenyl Compounds; Humans; Mitochondrial Membranes; Neoplasms; Nitrophenols; Piperazines; Proto-Oncogene Proteins c-bcl-2; Saccharomyces cerevisiae; Sulfonamides

The 'hallmarks of cancer' are generally accepted as a set of genetic and epigenetic alterations that a normal cell must accrue to transform into a fully malignant cancer. It follows that therapies designed to counter these alterations might be effective as anti-cancer strategies. Over the past 30 years, research on the BCL-2-regulated apoptotic pathway has led to the development of small-molecule compounds, known as 'BH3-mimetics', that bind to pro-survival BCL-2 proteins to directly activate apoptosis of malignant cells. This Timeline article focuses on the discovery and study of BCL-2, the wider BCL-2 protein family and, specifically, its roles in cancer development and therapy.

Topics: Animals; Apoptosis; bcl-2-Associated X Protein; Biphenyl Compounds; Cell Death; Gene Expression Regulation, Neoplastic; Genes, bcl-2; Humans; Mice; Mitochondrial Membrane Transport Proteins; Molecular Targeted Therapy; Multigene Family; Neoplasms; Nitrophenols; Piperazines; Proto-Oncogene Proteins c-bcl-2; Sulfonamides

The alteration in expression of B cell lymphoma-2 (Bcl-2) family of protein members in cancer is involved mainly in the regulation of apoptosis. Bcl-2 family proteins are currently used as major targets in the development of methods to improve treatment outcomes for cancer patients that underwent clinical trials. Although many agents have been developed for targeting Bcl-2 in the past decade, some previous attempts to target Bcl-2 have not resulted in beneficial clinical outcome for reasons unknown. Here, we propose that this was due in part for not considering the cellular level of a different antiapoptotic protein, i.e., galectin-3 (Gal-3). Gal-3 is a member of the β-galactoside binding protein family and a multifunctional oncogenic protein which regulates cell growth, cell adhesion, cell proliferation, angiogenesis, and apoptosis. Gal-3 is the sole protein that contains the NWGR anti-death motif of the Bcl-2 family and inhibits cell apoptosis induced by chemotherapeutic agents through phosphorylation, translocation and regulation of survival signaling pathways. It is now established that Gal-3 is a candidate target protein to suppress antiapoptotic activity and anticancer drug resistance. In this review, we describe the role and relevance of Gal-3 and Bcl-2 protein family in the regulation of apoptosis and propose a novel combination therapy modality. Combination therapy that targets Gal-3 could be essential for improvement of the efficacy of Bcl-2 targeting therapy in cancers and should be studied in future clinical trials. Otherwise, not considering Gal-3 cellular level could lead to trial failure.

Topics: Antineoplastic Agents; Biphenyl Compounds; Clinical Trials as Topic; Drug Therapy, Combination; Galectin 3; Humans; Molecular Targeted Therapy; Neoplasms; Nitrophenols; Piperazines; Polysaccharides; Proto-Oncogene Proteins c-bcl-2; Sulfonamides

The B-cell lymphoma/leukemia 2 (BCL-2) family of proteins has attracted the attention of cancer biologists since the cloning of BCL-2 more than 25 years ago. In the intervening decades, the way the BCL-2 family controls commitment to programmed cell death has been greatly elucidated. Several drugs directed at inhibiting BCL-2 and related antiapoptotic proteins have been tested clinically, with some showing considerable promise, particularly in lymphoid malignancies. A better understanding of the BCL-2 family has also provided insight into how conventional chemotherapy selectively kills cancer cells and why some cancers are more chemosensitive than others. Further exploitation of our understanding of the BCL-2 family promises to offer improved predictive biomarkers for oncologists and improved therapies for patients with cancer.

Topics: Aniline Compounds; Animals; Antineoplastic Agents; Apoptosis; Biphenyl Compounds; Drug Resistance, Neoplasm; Humans; Indoles; Molecular Targeted Therapy; Neoplasms; Nitrophenols; Piperazines; Proto-Oncogene Proteins c-bcl-2; Pyrroles; Sulfonamides; Thionucleotides; Treatment Outcome

Chemotherapy is an important therapeutic approach for cancer treatment. However, drug resistance is an obstacle that often impairs the successful use of chemotherapies. Therefore, overcoming drug resistance would lead to better therapeutic outcomes for cancer patients. Recently, studies by our own and other groups have demonstrated that there is an intimate correlation between the loss of the F-box and WD repeat domain-containing 7 (FBW7) tumor suppressor and the incurring drug resistance. While loss of FBW7 sensitizes cancer cells to certain drugs, FBW7-/- cells are more resistant to other types of chemotherapies. FBW7 exerts its tumor suppressor function by promoting the degradation of various oncoproteins that regulate many cellular processes, including cell cycle progression, cellular metabolism, differentiation, and apoptosis. Since loss of the FBW7 tumor suppressor is linked to drug resistance, FBW7 may represent a novel therapeutic target to increase drug sensitivity of cancer cells to conventional chemotherapeutics. This paper thus focuses on the new functional aspects of FBW7 in drug resistance.

Topics: Amyloid Precursor Protein Secretases; Apoptosis; Benzenesulfonates; Biphenyl Compounds; Cell Cycle Proteins; Drug Resistance, Neoplasm; F-Box Proteins; F-Box-WD Repeat-Containing Protein 7; Gene Expression Regulation, Neoplastic; Genes, Tumor Suppressor; Humans; MAP Kinase Signaling System; MicroRNAs; Myeloid Cell Leukemia Sequence 1 Protein; Neoplasms; Niacinamide; Nitrophenols; Paclitaxel; Phenylurea Compounds; Piperazines; Proto-Oncogene Proteins c-bcl-2; Pyridines; Sorafenib; Sulfonamides; Tumor Suppressor Protein p53; Ubiquitin-Protein Ligases; Ubiquitination; Vincristine

A critical regulator of the apoptotic machinery is the Bcl-2 family proteins whose over expression confers a protective effect on malignant cells against death signals of apoptosis. Cancer cells that are resistant to various anti-cancer drugs and treatment regimen are found to over express these Bcl-2 proteins such as Bcl-2, Bcl-X(L), Mcl-1, Bcl-w, and A1/Bfl1. In recent years there has been an exponential growth in the identification as well as synthesis of non-peptidic cell permeable small-molecule inhibitors (SMIs) of protein-protein interaction. The focus of this article is on inhibitors of anti-apoptotic protein Bcl-2. This review summarizes an up to date knowledge of the available SMIs, their mode of action as well as their current status in preclinical as well as clinical development.

Topics: Aniline Compounds; Animals; Apoptosis; Benzamides; Binding Sites; Biphenyl Compounds; Gossypol; Humans; Indoles; Lymphoma; Models, Molecular; Neoplasms; Nitrophenols; Piperazines; Protein Structure, Tertiary; Proto-Oncogene Proteins c-bcl-2; Pyrroles; Sulfonamides; Sulfones

Despite tremendous advances over the last 15 years in understanding fundamental mechanisms of apoptosis, this has failed to translate into improved cancer therapy for patients. However, there may now be light at the end of this long tunnel. Antiapoptotic Bcl-2 family members may be divided into two subclasses, one comprising Bcl-2, Bcl-X(L) and Bcl-w and the other Mcl-1 and Bcl2A1. Neutralization of both subclasses is required for apoptosis induction. Solution of the structure of antiapoptotic Bcl-2 family proteins has led to the design of novel small molecule inhibitors. Although many such molecules have been synthesized, rigorous verification of their specificity has often been lacking. Further studies have revealed that many putative Bcl-2 inhibitors are not specific and have other cellular targets, resulting in non-mechanism based toxicity. Two notable exceptions are ABT-737 and a related orally active derivative, ABT-263, which bind with high affinity to Bcl-2, Bcl-X(L) and Bcl-w and may prove to be useful tools for mechanistic studies. ABT-263 is in early clinical trials in lymphoid malignancies, small-cell lung cancer and chronic lymphocytic leukemia, and some patients have shown promising results. In in vitro studies, primary cells from patients with various B-cell malignancies are exquisitely sensitive to ABT-737, exhibiting novel morphological features of apoptosis including marked outer mitochondrial membrane rupture.

Topics: Aniline Compounds; Apoptosis; Biphenyl Compounds; Cells, Cultured; Humans; Lymphoma, Mantle-Cell; Molecular Structure; Neoplasms; Nitrophenols; Piperazines; Proto-Oncogene Proteins c-bcl-2; Sulfonamides

Defects in apoptotic pathways can promote cancer cell survival and also confer resistance to antineoplastic drugs. One pathway being targeted for antineoplastic therapy is the anti-apoptotic B-cell lymphoma-2 (Bcl-2) family of proteins (Bcl-2, Bcl-XL, Bcl-w, Mcl-1, Bfl1/A-1, and Bcl-B) that bind to and inactivate BH3-domain pro-apoptotic proteins. Signals transmitted by cellular damage (including antineoplastic drugs) or cytokine deprivation can initiate apoptosis via the intrinsic apoptotic pathway. It is controversial whether some BH3-domain proteins (Bim or tBid) directly activate multidomain pro-apoptotic proteins (e.g., Bax and Bak) or act via inhibition of those anti-apoptotic Bcl-2 proteins (Bcl-2, Bcl-XL, Bcl-w, Mcl-1, Bfl1/A-1, and Bcl-B) that stabilize pro-apoptotic proteins. Overexpression of anti-apoptotic Bcl-2 family members has been associated with chemotherapy resistance in various human cancers, and preclinical studies have shown that agents targeting anti-apoptotic Bcl-2 family members have preclinical activity as single agents and in combination with other antineoplastic agents. Clinical trials of several investigational drugs targeting the Bcl-2 family (oblimersen sodium, AT-101, ABT-263, GX15-070) are ongoing. Here, we review the role of the Bcl-2 family in apoptotic pathways and those agents that are known and/or designed to inhibit the anti-apoptotic Bcl-2 family of proteins.

Topics: Aniline Compounds; Animals; Antineoplastic Agents; Apoptosis; Biphenyl Compounds; Gossypol; Humans; Indoles; Mitochondria; Neoplasms; Nitrophenols; Piperazines; Proto-Oncogene Proteins c-bcl-2; Pyrroles; Sulfonamides; Thionucleotides

Numerous data indicate that defects in apoptotic signaling pathways contribute to the development of cancer and to therapy resistance in many types of malignant tumors. Defective apoptotic cell death is not only a significant cause of cancer, but also increases tumor resistance to chemo- and radiotherapy. Therefore, there is an urgent need to elucidate the molecular basis of apoptosis resistance and to develop novel strategies to overcome this resistance. One important task is the identification of those anti-apoptotic proteins that render tumor cells resistant to therapy and to investigate how these resistance mechanisms can be regulated on a cellular and molecular level. Based on these findings, novel strategies to sensitize cancer cells to cell death induction can be developed. Moreover, the expression profiles of several apoptosis-regulating proteins can be used as prognostic factors in patients with diverse types of cancer.

Topics: Animals; Antineoplastic Agents; Apoptosis; Biphenyl Compounds; Cell Line, Tumor; Cell Survival; Cell Transformation, Neoplastic; Drug Resistance, Neoplasm; Humans; Neoplasms; Nitrophenols; Piperazines; Proto-Oncogene Proteins c-bcl-2; Receptors, Death Domain; Signal Transduction; Sulfonamides; TNF-Related Apoptosis-Inducing Ligand

Cancer cells show deviant behavior that induces apoptotic signaling. To survive, cancer cells typically acquire changes enabling evasion of death signals. One way they do this is by increasing the expression of anti-apoptotic BCL-2 proteins. Anti-apoptotic BCL-2 family proteins antagonize death signaling by forming heterodimers with pro-death proteins. Heterodimer formation occurs through binding of the pro-apoptotic protein's BH3 domain into the hydrophobic cleft of anti-apoptotic proteins. The BH3 mimetics are small molecule antagonists of the anti-apoptotic BCL-2 members that function as competitive inhibitors by binding to the hydrophobic cleft. Under certain conditions, antagonism of anti-apoptotic BCL-2 family proteins can unleash pro-death molecules in cancer cells. Thus, the BH3 mimetics are a new class of cancer drugs that specifically target a mechanism of cancer cell survival to selectively kill cancer cells.

Topics: Aniline Compounds; Animals; Antineoplastic Agents; Apoptosis; Benzamides; Binding, Competitive; Biphenyl Compounds; Clinical Trials as Topic; Dimerization; Drug Delivery Systems; Drug Design; Drug Resistance, Neoplasm; Drug Screening Assays, Antitumor; Humans; Indoles; Mice; Mitochondria; Multigene Family; Neoplasm Proteins; Neoplasms; Nitrophenols; Piperazines; Protein Structure, Tertiary; Proto-Oncogene Proteins c-bcl-2; Pyrroles; Structure-Activity Relationship; Sulfonamides; Sulfones; Thionucleotides

Induction of apoptosis in tumor cells by direct activation of the Bcl-2-regulated apoptosis pathway by small molecule drugs carries high hopes to overcome the shortcomings of current anticancer therapies. This novel therapy concept builds on emerging insights into how Bcl-2-like molecules maintain mitochondrial integrity and how pro-apoptotic BH3-only proteins lead to its disruption. Means to unleash the pro-apoptotic potential of BH3-only proteins in tumor cells, or to bypass the need for BH3-only proteins by directly blocking possible interactions of Bcl-2-like pro-survival molecules with Bax and/or Bak, constitute interesting options for the design of novel anticancer therapies. For the optimization and clinical implementation of these novel anticancer strategies, a detailed understanding of the role of individual BH3-only proteins in cell death signaling in healthy cells and during tumor suppression is required. In this review, we will touch on the latest findings on BH3-only protein function and attempts to define the molecular properties of the so-called 'BH3 mimetics,' a novel class of anticancer agents, able to prompt apoptosis in tumor cells, regardless of their p53 or Bcl-2 status.

Topics: Antineoplastic Agents; Apoptosis; Biphenyl Compounds; Drug Resistance, Neoplasm; Humans; Molecular Mimicry; Neoplasms; Nitrophenols; Piperazines; Protein Structure, Tertiary; Proto-Oncogene Proteins c-bcl-2; Signal Transduction; Sulfonamides

ABT-737 targets Bcl-2/Bcl-xL but not Mcl-1, which confers resistance to this novel agent. Here, we summarize recent findings indicating that Mcl-1 represents a critical determinant of ABT-737 sensitivity and resistance, and that Mcl-1 down-regulation by various pharmacologic agents or genetic approaches dramatically increases ABT-737 lethality in diverse malignant cell types. These findings also show that the multidomain proapoptotic proteins Bax and Bak play important functional roles in ABT-737-mediated apoptosis, and that Bak activation is essential in potentiation of ABT-737 lethality by agents that down-regulate Mcl-1. Collectively, these findings suggest a novel therapeutic strategy targeting multiple arms of the apoptotic machinery.

Topics: Apoptosis; bcl-2 Homologous Antagonist-Killer Protein; bcl-2-Associated X Protein; Biphenyl Compounds; Humans; Myeloid Cell Leukemia Sequence 1 Protein; Neoplasm Proteins; Neoplasms; Nitrophenols; Piperazines; Proto-Oncogene Proteins c-bcl-2; Sulfonamides

Apoptosis is essential for tissue homeostasis, particularly in the hematopoietic compartment, where its impairment can elicit neoplastic or autoimmune diseases. Whether stressed cells live or die is largely determined by interplay between opposing members of the Bcl-2 protein family. Bcl-2 and its closest homologs promote cell survival, but two other factions promote apoptosis. The BH3-only proteins sense and relay stress signals, but commitment to apoptosis requires Bax or Bak. The BH3-only proteins appear to activate Bax and Bak indirectly, by engaging and neutralizing their pro-survival relatives, which otherwise constrain Bax and Bak from permeabilizing mitochondria. The Bcl-2 family may also regulate autophagy and mitochondrial fission/fusion. Its pro-survival members are attractive therapeutic targets in cancer and perhaps autoimmunity and viral infections.

Topics: Animals; Antineoplastic Agents; Apoptosis; Apoptosis Regulatory Proteins; Autophagy; BH3 Interacting Domain Death Agonist Protein; Biphenyl Compounds; Humans; Metabolic Networks and Pathways; Mitochondria; Molecular Mimicry; Neoplasms; Nitrophenols; Piperazines; Proto-Oncogene Proteins c-bcl-2; Sulfonamides

Tumor cell survival is highly dependent on the expression of certain pro-survival Bcl-2 family proteins. An attractive therapeutic approach is to inhibit these proteins using agents that mimic the Bcl-2 homology 3 (BH3) domains of the proapoptotic Bcl-2 family members, which neutralize these proteins by binding to their surface hydrophobic grooves. A number of BH3 mimetic peptides and small molecules have been described, a few of which have advanced into clinical trials. Recent studies have highlighted ABT-737, a bona fide BH3 mimetic and potent inhibitor of antiapoptotic Bcl-2 family members, as a promising anticancer agent. This review summarizes recent advances in understanding the mechanisms of action of BH3 domains and several classes of BH3 mimetics, as well as the prospects of using these agents to improve cancer therapy.

Topics: Amino Acid Sequence; Animals; Antineoplastic Agents; Apoptosis; bcl-X Protein; Biphenyl Compounds; Drug Resistance, Neoplasm; Drugs, Investigational; Humans; Molecular Sequence Data; Myeloid Cell Leukemia Sequence 1 Protein; Neoplasm Proteins; Neoplasms; Nitrophenols; Piperazines; Protein Structure, Tertiary; Proto-Oncogene Proteins c-bcl-2; Sequence Alignment; Sulfonamides; Treatment Outcome

Impairment of apoptosis, the physiologic cell death process, is central to cancer development and renders tumors refractory to cytotoxic therapy. Bcl-2, the oncoprotein activated in follicular lymphoma, inhibits the conserved cell death pathway triggered by diverse cytotoxic agents, as do several close relatives. A small-molecule antagonist of these proteins has now been designed by Oltersdorf et al. Strikingly, ABT-737 sensitizes many tumors to cytotoxic agents and is effective as a single agent against certain lymphomas and solid tumors, provoking stable regression in some tumor xenografts. Hence, this work validates Bcl-2-like proteins as important new targets in cancer therapy.

Topics: Apoptosis; bcl-2-Associated X Protein; Biphenyl Compounds; Humans; Neoplasms; Nitrophenols; Piperazines; Proto-Oncogene Proteins c-bcl-2; Sulfonamides

The BCL-2 gene was first cloned in 1985 from the t(14;18) chromosomal translocation found in nearly all follicular lymphomas. BCL-2 is understood to have a central role in inhibiting apoptosis. Now, Oltersdorf et al. report the development of a high-affinity, mechanistically validated small-molecule antagonist of BCL-2 that kills cancer in mouse xenograft models and primary human cancer cells in vitro. The two decades spanning these two achievements provide an interesting case study of rational drug development. The investigation of antiapoptotic protein antagonists holds new promise for selectively inducing programmed cell death in cancer cells.

Topics: Animals; Apoptosis; Biphenyl Compounds; Cell Line, Tumor; Drug Design; Humans; Mice; Neoplasms; Nitrophenols; Nuclear Magnetic Resonance, Biomolecular; Piperazines; Proto-Oncogene Proteins c-bcl-2; Signal Transduction; Structure-Activity Relationship; Sulfonamides

Over the past 10 years evidence has been accumulating that antitumour agents induce apoptosis in cancer cells and that abnormalities in apoptosis signaling pathways often occur in cancer cells and are associated with drug resistance. The implication is that factors regulating the apoptotic process play a critical role in tumour sensitivity to chemotherapy, and hence may be rational molecular targets for novel antitumour agents. Significantly, oncogenic signals make cancer cells intrinsically more susceptible to apoptosis; defects in the pathway occur subsequent to cancer development. Important emerging questions are the pattern of alterations in the apoptotic pathway in a particular tumour (cell) and the best strategy to exploit them and induce selective tumour cell death. Here, we review recent progress in this field.

Topics: Animals; Antineoplastic Agents; Apoptosis; Biphenyl Compounds; Caspase 3; Cell Transformation, Neoplastic; Enzyme Activators; Humans; Inhibitor of Apoptosis Proteins; Neoplasms; Nitrophenols; Oligonucleotides, Antisense; Piperazines; Proto-Oncogene Proteins c-bcl-2; Pyridines; Sulfonamides; Triazenes

Chemotherapy-induced thrombocytopenia is a common bleeding risk in cancer patients and limits chemotherapy dose and frequency. Recent data from mouse and human platelets revealed that activation of protein kinase A/G (PKA/PKG) not only inhibited thrombin/convulxin-induced platelet activation but also prevented the platelet pro-coagulant state. Here we investigated whether or not PKA/PKG activation could attenuate caspase-dependent apoptosis induced by the anti-cancer drugs ABT-737 (the precursor of navitoclax) and thymoquinone (TQ), thereby potentially limiting chemotherapy-induced thrombocytopenia. This is particularly relevant as activation of cyclic nucleotide signalling in combination chemotherapy is an emerging strategy in cancer treatment. However, PKA/PKG-activation, as monitored by phosphorylation of Vasodilator-stimulated phosphoprotein (VASP), did not block caspase-3-dependent platelet apoptosis induced by the compounds. In contrast, both substances induced PKA activation themselves and PKA activation correlated with platelet inhibition and apoptosis. Surprisingly, ABT-737- and TQ-induced VASP-phosphorylation was independent of cAMP levels and neither cyclases nor phosphatases were affected by the drugs. In contrast, however, ABT-737- and TQ-induced PKA activation was blocked by caspase-3 inhibitors. In conclusion, we show that ABT-737 and TQ activate PKA in a caspase-3-dependent manner, which correlates with platelet inhibition and apoptosis and therefore potentially contributes to the bleeding risk in chemotherapy patients.

Topics: Animals; Apoptosis; Benzoquinones; Biphenyl Compounds; Blood Platelets; Caspase 3; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Cyclic GMP-Dependent Protein Kinases; Humans; Mice; Neoplasms; Nitrophenols; Piperazines; Platelet Activation; Sulfonamides; Thrombocytopenia

ABT-737 is a BH3 mimetic inhibitor of Bcl-xL, Bcl-2, and Bcl-w, and it has been reported for anti-cancer effects in various types of cancer cells. However, ABT-737 fails to induce apoptosis in cancer cell with high levels of Mcl-1 expression. The pharmacological survivin inhibitor YM155 has been reported to induce downregulation of Mcl-1 expression. Therefore, we investigated the effect of YM155 to sensitize resistance against ABT-737 in Mcl-1-overexpressed human renal carcinoma Caki cells. We found that ABT-737 alone and YM155 alone did not induce apoptosis, but YM155 markedly sensitized ABT-737-mediated apoptosis in Mcl-1-overexpressed Caki cells, human glioma cells (U251MG), and human lung carcinoma cells (A549). In contrast, combined treatment with ABT-737 and YM155 did not increase apoptosis in normal mouse kidney cells (TCMK-1) and human mesangial cells (MC). YM155 induced lysosome-dependent downregulation of Mcl-1 expression in Mcl-1-overexpressed Caki cells. In addition, combined treatment with ABT-737 and YM155 induced loss of mitochondrial membrane potential and inhibited interaction of Bcl-xL and Bax. Taken together, our results suggested that YM155 effectively improves sensitivity to ABT-737 through downregulation of Mcl-1 expression.

Topics: A549 Cells; Animals; Apoptosis; Biphenyl Compounds; Cell Line, Tumor; Cell Survival; Down-Regulation; Drug Resistance, Neoplasm; Drug Synergism; Gene Expression Regulation, Neoplastic; Humans; Imidazoles; Membrane Potential, Mitochondrial; Mice; Myeloid Cell Leukemia Sequence 1 Protein; Naphthoquinones; Neoplasms; Nitrophenols; Piperazines; Sulfonamides

Polysaccharopeptide (PSP), from Coriolus versicolor, has been used widely as an adjuvant to chemotherapy with demonstrated anti-tumor and broad immunomodulating effects. While PSP's mechanism of action still remains unknown, its enhanced immunomodulatory potential with acacia gum is of great interest. Acacia gum, which also contains polysaccharides and glycoproteins, has been demonstrated to be immunopotentiating. To elucidate whether PSP directly activates T-cell-dependent B-cell responses in vivo, we used a well-established hapten carrier system (Nitrophenyl-chicken gamma globulin (NP-CGG)). 6-week C57BL/6 male mice were immunised with 50 μg of NP25-CGG alum precipitate intraperitoneally. Mice were gavaged daily with 50 mg/kg PSP in a vehicle containing acacia gum and sacrificed at days 0, 4, 7, 10, 14 and 21. ELISA was used to measure the total and relative hapten-specific anti-NP IgA, IgM and IgG titre levels compared to the controls. It was found that PSP, combined with acacia gum, significantly increased total IgG titre levels at day 4 (P< 0.05), decreased IgM titre levels at days 4 and 21 (P< 0.05) with no alterations observed in the IgA or IgE titre levels at any of the time points measured. Our results suggest that while PSP combined with acacia gum appears to exert weak immunological effects through specific T-cell dependent B-cell responses, they are likely to be broad and non-specific which supports the current literature on PSP. We report for the first time the application of a well-established hapten-carrier system that can be used to characterise and delineate specific T-cell dependent B-cell responses of potential immunomodulatory glycoprotein-based herbal medicines combinations in vivo.

Topics: Adjuvants, Immunologic; Animals; Antibodies; B-Lymphocytes; gamma-Globins; Gum Arabic; Haptens; Immunization; Immunoglobulin G; Immunoglobulin M; Immunotherapy; Lymphocyte Activation; Male; Mice; Mice, Inbred C57BL; Neoplasms; Nitrophenols; Phenylacetates; Proteoglycans; T-Lymphocytes; Trametes

Epothilone B and its derivatives are tested in multiple clinical trials. Epothilone B induces neurotoxic effect in clinical trials; however, low-dose epothilone B regimen can promote neuroprotection and neurogenesis. Thus, the study of new combination chemotherapy regimen incorporating low-dose epothilone B with other chemotherapeutic agents might help to develop epothilone B-based approaches to cancer treatment and avoid the neurotoxicity of epothilone B.. Cell proliferation was assessed by SRB cell viability assay. Apoptosis was analyzed by propidium iodide (PI) staining. Mitochondrial membrane depolarization was evaluated using JC-1 staining. The expression of proteins was detected by western blotting.. In this study, we demonstrated that the combination of ABT-737 and low-dose epothilone B showed synergistic anti-proliferation effects on human cancer cells. In addition, epothilone B + ABT-737 synergy was through mitochondria-mediated apoptosis pathway. Furthermore, combination treatment markedly induced the activation of caspase-3 and the cleavage of PARP. The activation of PI3K/Akt/mTOR pathway is associated with resistance to epothilone B. Our data showed that epothilone B plus ABT-737 resulted in a blockade of the PI3K/AKT/mTOR signaling pathway.. These data indicate that ABT-737 may be a pertinent sensitizer to epothilone B, and the strategy of combining epothilone B with ABT-737 appears to be an attractive option for overcoming the resistance and neurotoxicity of epothilone B.

Topics: Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Biphenyl Compounds; Cell Line, Tumor; Cell Proliferation; Drug Synergism; Epothilones; Humans; Mitochondria; Neoplasms; Nitrophenols; Phosphatidylinositol 3-Kinases; Piperazines; Proto-Oncogene Proteins c-akt; Signal Transduction; Sulfonamides; TOR Serine-Threonine Kinases

Regular use of aspirin after diagnosis is associated with longer survival among patients with mutated-PIK3CA colorectal cancer, but not among patients with wild-type PIK3CA cancer. In this study, we showed that clinically achievable concentrations of aspirin and ABT-737 in combination could induce a synergistic growth arrest in several human PIK3CA wild-type cancer cells. In addition, our results also demonstrated that long-term combination treatment with aspirin and ABT-737 could synergistically induce apoptosis both in A549 and H1299 cells. In the meanwhile, short-term aspirin plus ABT-737 combination treatment induced a greater autophagic response than did either drug alone and the combination-induced autophagy switched from a cytoprotective signal to a death-promoting signal. Furthermore, we showed that p38 acted as a switch between two different types of cell death (autophagy and apoptosis) induced by aspirin plus ABT-737. Moreover, the increased anti-cancer efficacy of aspirin combined with ABT-737 was further validated in a human lung cancer A549 xenograft model. We hope that this synergy may contribute to failure of aspirin cancer therapy and ultimately lead to efficacious regimens for cancer therapy.

Topics: Apoptosis; Aspirin; Autophagy; Biphenyl Compounds; Cell Line, Tumor; Humans; Neoplasms; Nitrophenols; p38 Mitogen-Activated Protein Kinases; Piperazines; Sulfonamides

Semiconductor quantum dots (QDs), after surface modification to provide water solubility and biocompatibility, have a promising future in biomedical applications. In this study, a dual receptor-targeting dual-modality PET/near-infrared fluorescence (NIRF) probe was developed for accurate assessment of the pharmacokinetics and tumor-targeting efficacy of QDs.. QDs were modified by β-Glu-RGD-BBN (RGD is arginine-glycine-aspartate acid, and BBN is bombesin) peptides and then labeled with (18)F via the 4-nitrophenyl-2-(18)F-fluoropropionate prosthetic group. Cytotoxicity and cell-binding assay of QD-RGD-BBN were performed with PC-3 cells. In vivo dual-modality PET/NIRF imaging of prostate tumor-bearing mice was investigated using QD-RGD-BBN and 2-(18)F-fluoropropionyl-QD-RGD-BBN ((18)F-FP-QD-RGD-BBN). An in vivo biodistribution study of (18)F-FP-QD-RGD-BBN was performed on normal mice.. QD-RGD-BBN exhibited strong red luminescence (600-800 nm) with the same maximum fluorescence wavelength (705 nm) as QD705 and slightly lower toxicity than that of QD705 in PC-3 cells at concentrations of greater than 30 μg/mL. Uptake of QD-RGD-BBN in PC-3 cells showed no significant decrease in the presence of an excess amount of dimer arginine-glycine-aspartate acid (RGD2) or bombesin(7-14) (BBN) peptide but was blocked significantly in the presence of an excess amount of NH2-RGD-BBN. Dual-function PET/NIRF imaging is able to accurately assess the biodistribution and tumor-targeting efficacy of the (18)F-labeled functionalized QDs.. The functionalized QD probe has great potential as a universal dual-targeting probe for detecting tumors in living subjects, opening up a new strategy for the development of multitargeting multimodality (18)F-labeled QD probes with improved tumor-targeting efficacy.

Topics: Animals; Biocompatible Materials; Bombesin; Copper Radioisotopes; Female; Male; Mice; Mice, Inbred BALB C; Neoplasm Transplantation; Neoplasms; Nitrophenols; Oligopeptides; Peptides; Positron-Emission Tomography; Prostatic Neoplasms; Quantum Dots; Receptors, Bombesin; Semiconductors; Spectrometry, Fluorescence; Tissue Distribution

Topics: Adolescent; Adult; Aged, 80 and over; Chemical Hazard Release; Chemical Industry; Environmental Exposure; Environmental Pollution; Female; Follow-Up Studies; Germany; Humans; Male; Middle Aged; Neoplasms; Nitrophenols; Proportional Hazards Models; Residence Characteristics; Risk Factors; Young Adult

Members of the Bcl-2 family of proteins are important inhibitors of apoptosis in human cancer and are targets for novel anticancer agents such as the Bcl-2 antagonists, ABT-263 (Navitoclax), and its analog ABT-737. Unlike Bcl-2, Mcl-1 is not antagonized by ABT-263 or ABT-737 and is considered to be a major factor in resistance. Also, Mcl-1 exhibits differential regulation when compared with other Bcl-2 family members and is a target for anticancer drug discovery. Here, we demonstrate that BAG3, an Hsp70 co-chaperone, protects Mcl-1 from proteasomal degradation, thereby promoting its antiapoptotic activity. Using neuroblastoma cell lines, with a defined Bcl-2 family dependence, we found that BAG3 expression correlated with Mcl-1 dependence and ABT-737 resistance. RNA silencing of BAG3 led to a marked reduction in Mcl-1 protein levels and overcame ABT-737 resistance in Mcl-1-dependent cells. In ABT-737-resistant cells, Mcl-1 co-immunoprecipitated with BAG3, and loss of Mcl-1 after BAG3 silencing was prevented by proteasome inhibition. BAG3 and Mcl-1 were co-expressed in a panel of diverse cancer cell lines resistant to ABT-737. Silencing BAG3 reduced Mcl-1 protein levels and overcame ABT-737 resistance in several of the cell lines, including triple-negative breast cancer (MDA-MB231) and androgen receptor-negative prostate cancer (PC3) cells. These studies identify BAG3-mediated Mcl-1 stabilization as a potential target for cancer drug discovery.

Topics: Adaptor Proteins, Signal Transducing; Antineoplastic Agents; Apoptosis; Apoptosis Regulatory Proteins; Biphenyl Compounds; Cell Line, Tumor; Cell Survival; Drug Resistance, Neoplasm; Gene Expression Regulation, Neoplastic; HEK293 Cells; Humans; Immunoblotting; Myeloid Cell Leukemia Sequence 1 Protein; Neoplasms; Nitrophenols; Piperazines; Proteasome Endopeptidase Complex; Protein Binding; Protein Stability; Proteolysis; Proto-Oncogene Proteins c-bcl-2; Reverse Transcriptase Polymerase Chain Reaction; RNA Interference; Sulfonamides; Ubiquitination

ABT-737, a novel small molecule inhibitor of Bcl-2 family proteins, holds great promise to complement current cancer therapies. However many types of solid cancer cells are resistant to ABT-737. One practical approach to improve its therapeutic efficacy is to combine with the agents that can overcome such resistance to restore the sensitivity. In the present study, a second-generation selenium compound methylseleninic acid (MSeA) synergistically sensitized MDA-MB-231 human breast cancer cells, HT-29 human colon cancer cells and DU145 human prostate cancer cells to apoptosis induction by ABT-737, as evidenced by greater than additive enhancement of Annexin V/FITC positive (apoptotic) cells and activation of multiple caspases and PARP cleavage. Mechanistic investigation demonstrated that MSeA significantly decreased basal Mcl-1 expression and ABT-737-induced Mcl-1 expression. Knocking down of Mcl-1 with RNAi approach supported the functional significance of this molecular target. More importantly, we identified inactivation of Bad by phosphorylation on ser-136 and ser-112 as a novel mechanism involved in ABT-737 resistance, which can be overcome by combining with MSeA. In addition, we found that expression of Bax was required for the efficient execution of synergistic sensitization. Our findings, for the first time, provide a strong mechanistic rationale for developing MSeA as a novel sensitizing agent of ABT-737.

Topics: Apoptosis; bcl-Associated Death Protein; Biphenyl Compounds; Cell Line, Tumor; Drug Synergism; Gene Expression Regulation, Neoplastic; HT29 Cells; Humans; Myeloid Cell Leukemia Sequence 1 Protein; Neoplasms; Nitrophenols; Organoselenium Compounds; Piperazines; Proto-Oncogene Proteins c-bcl-2; Sulfonamides

Mcl-1, an anti-apoptotic Bcl-2 homolog that has a structurally divergent BH3-binding pocket, non-redundant action model, and unique characteristic of short life confers complete resistance to the BH3 mimetic ABT-737. Herein, we used S1, previously identified as a Mcl-1/Bcl-2 dual inhibitor and a pure BH3 mimetic, to explore the mechanism of Mcl-1's action and supply a strategy to challenge Mcl-1's protection. Apoptosis assay in SMMC-7721, HCT116, and K562 cells demonstrated that S1 can effectively challenge Mcl-1's anti-apoptotic effect. Notably, we discovered an unexpected dynamic change of Mcl-1 that directly correlates with resistance or commitment to apoptosis induced by both ABT-737 and S1. Co-immunoprecipitation assays demonstrated that Mcl-1 increase results from Bim trafficking from Bcl-2 to Mcl-1, while subsequent Bak released by S1 determines Mcl-1 decrease and full-blown apoptosis. Further experiments using Bak shRNA testified that Bak accounts for S1-induced apoptosis and Mcl-1 decrease. Consistently, Bax-deficient DU145 cells are sensitive to S1, whereas Bak-mutant MKN-28 cells are significantly more resistant. The in vitro model could be extended to an in vivo mouse xenograft model in which Mcl-1 confers resistance by increased protein level, and the release of Bak could serve as a biomarker of apoptosis.

Topics: Acenaphthenes; Animals; Antineoplastic Agents; Apoptosis; bcl-2 Homologous Antagonist-Killer Protein; Biphenyl Compounds; Cell Line, Tumor; Humans; Mice; Mice, Inbred BALB C; Myeloid Cell Leukemia Sequence 1 Protein; Neoplasms; Nitrophenols; Peptide Fragments; Piperazines; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Pyrroles; Sulfonamides; Tumor Burden; Xenograft Model Antitumor Assays

BIM represents a BH3-only proapoptotic member of the BCL-2 family of apoptotic regulatory proteins. Recent evidence suggests that in addition to its involvement in normal homeostasis, BIM plays a critical role in tumor cell biology, including the regulation of tumorigenesis through activities as a tumor suppressor, tumor metastasis, and tumor cell survival. Consequently, BIM has become the focus of intense interest as a potential target for cancer chemotherapy. The control of BIM expression is complex, and involves multiple factors, including epigenetic events (i.e., promoter acetylation or methylation, miRNA), transcription factors, posttranscriptional regulation, and posttranslational modifications, most notably phosphorylation. Significantly, the expression of BIM by tumor cells has been shown to play an important role in determining the response of transformed cells to not only conventional cytotoxic agents, but also to a broad array of targeted agents that interrupt cell signaling and survival pathways. Furthermore, modifications in BIM expression may be exploited to improve the therapeutic activity and potentially the selectivity of such agents. It is likely that evolving insights into the factors that regulate BIM expression will ultimately lead to novel BIM-based therapeutic strategies in the future.

Topics: Acetylation; Animals; Antineoplastic Agents; Apoptosis; Apoptosis Regulatory Proteins; Bcl-2-Like Protein 11; Biphenyl Compounds; Cell Transformation, Neoplastic; DNA Methylation; Drug Synergism; Forkhead Box Protein O3; Forkhead Transcription Factors; Gene Expression Regulation, Neoplastic; Histone Deacetylase Inhibitors; Humans; MAP Kinase Signaling System; Membrane Proteins; Neoplasms; Nitrophenols; Phosphorylation; Piperazines; Promoter Regions, Genetic; Proteasome Endopeptidase Complex; Proteasome Inhibitors; Proto-Oncogene Proteins; Sulfonamides; Transcription Factors; Transcription, Genetic

ABT-737, a small molecule cell-permeable Bcl-2 antagonist that acts by mimicking BH3 proteins, induces apoptotic cell death in multiple cancer types. However, when incubated with this agent many solid tumor cell lines do not undergo apoptosis. The current study reveals a novel mechanism whereby ABT-737 when added to apoptosis-resistant cancer cells has profound biologic effects. In PV-10 cells, a renal cell carcinoma that does not die after ABT-737 treatment, this agent induces a two-fold change in the transcription of nearly 430 genes. Many of these induced mRNA changes are in secreted proteins, IL-6, IL-8, and IL-11 and chemokines CXCL2 and CXCL5, or genes associated with an "inflammatory" phenotype. Strikingly, these gene changes are highly similar to those changes previously identified in cellular senescence. Brief exposure of apoptosis-resistant renal, lung and prostate cancer cell lines to ABT-737, although not capable of inducing cell death, causes the induction of senescence-associated β-galactosidase and inhibition of cell growth consistent with the induction of cellular senescence. Evidence indicates that the induction of senescence occurs as a result of reactive oxygen species elevation followed by low-level activation of the caspase cascade, insufficient to induce apoptosis, but sufficient to lead to minor DNA damage and increases in p53, p21, IL-6 and 8 proteins. By overexpression of a dominant-negative p53 protein, we show that ABT-737-induced cellular senescence is p53-dependent. Thus, in multiple cancer types in which ABT-737 is incapable of causing cell death, ABT-737 may have additional cellular activities that make its use as an anticancer agent highly attractive.

Topics: Biomimetic Materials; Biphenyl Compounds; Caspase 3; Cell Cycle; Cell Growth Processes; Cell Line, Tumor; Cellular Senescence; Chemokine CXCL2; Chemokine CXCL5; Cyclin-Dependent Kinase Inhibitor p21; DNA Damage; Humans; Interleukin-6; Interleukin-8; Neoplasms; Nitrophenols; Peptide Fragments; Piperazines; Proto-Oncogene Proteins; Sulfonamides; Transcriptional Activation; Tumor Suppressor Protein p53

Solid tumors contain hypoxic regions in which cancer cells are often resistant to chemotherapy-induced apoptotic cell death. Therapeutic strategies that specifically target hypoxic cells and promote apoptosis are particularly appealing, as few normal tissues experience hypoxia. We have found that the compound ABT-737, a Bcl-2 homology domain 3 (BH-3) mimetic, promotes apoptotic cell death in human colorectal carcinoma and small cell lung cancer cell lines exposed to hypoxia. This hypoxic induction of apoptosis was mediated through downregulation of myeloid cell leukemia sequence 1 (Mcl-1), a Bcl-2 family protein that serves as a biomarker for ABT-737 resistance. Downregulation of Mcl-1 in hypoxia was independent of hypoxia-inducible factor 1 (HIF-1) activity and was consistent with decreased global protein translation. In addition, ABT-737 induced apoptosis deep within tumor spheroids, consistent with an optimal hypoxic oxygen tension being necessary to promote ABT-737–induced cell death. Tumor xenografts in ABT-737–treated mice also displayed significantly more apoptotic cells within hypoxic regions relative to normoxic regions. Synergies between ABT-737 and other cytotoxic drugs were maintained in hypoxia, suggesting that this drug may be useful in combination with chemotherapeutic agents. Taken together, these findings suggest that Mcl-1–sparing BH-3 mimetics may induce apoptosis in hypoxic tumor cells that are resistant to other chemotherapeutic agents and may have a role in combinatorial chemotherapeutic regimens for treatment of solid tumors.

Topics: Animals; Apoptosis; Biphenyl Compounds; Cell Line, Tumor; Down-Regulation; Drug Resistance, Neoplasm; Drug Screening Assays, Antitumor; Humans; Hypoxia; Inhibitory Concentration 50; Male; Mice; Myeloid Cell Leukemia Sequence 1 Protein; Neoplasm Transplantation; Neoplasms; Nitrophenols; Peptide Fragments; Piperazines; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Sulfonamides

Schistosomiasis is an infectious disease caused by parasites of the phylum platyhelminthe. Here, we describe the identification and characterization of a Bcl-2-regulated apoptosis pathway in Schistosoma japonicum and S. mansoni. Genomic, biochemical, and cell-based mechanistic studies provide evidence for a tripartite pathway, similar to that in humans including BH3-only proteins that are inhibited by prosurvival Bcl-2-like molecules, and Bax/Bak-like proteins that facilitate mitochondrial outer-membrane permeabilization. Because Bcl-2 proteins have been successfully targeted with "BH3 mimetic" drugs, particularly in the treatment of cancer, we investigated whether schistosome apoptosis pathways could provide targets for future antischistosomal drug discovery efforts. Accordingly, we showed that a schistosome prosurvival protein, sjA, binds ABT-737, a well-characterized BH3 mimetic. A crystal structure of sjA bound to a BH3 peptide provides direct evidence for the feasibility of developing BH3 mimetics to target Bcl-2 prosurvival proteins in schistosomes, suggesting an alternative application for this class of drugs beyond cancer treatment.

Topics: Animals; Apoptosis; Biphenyl Compounds; Crystallography, X-Ray; Helminth Proteins; Humans; Neoplasms; Nitrophenols; Peptide Fragments; Piperazines; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Schistosoma japonicum; Schistosoma mansoni; Schistosomiasis japonica; Schistosomiasis mansoni; Sulfonamides

Topics: Animals; Apoptosis; Biphenyl Compounds; Crystallography, X-Ray; Helminth Proteins; Humans; Neoplasms; Nitrophenols; Peptide Fragments; Piperazines; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Schistosoma japonicum; Schistosoma mansoni; Schistosomiasis japonica; Schistosomiasis mansoni; Sulfonamides

The Bcl-2 antagonist ABT-737 targets Bcl-2/Bcl-xL, but not Mcl-1, which may confer resistance to this agent in various cancers with high levels of Mcl-1. Here, we showed that the combination of gemcitabine and ABT-737 exhibited synergistic cytotoxicity and induced significant apoptosis in multiple cancer types, including lung, renal, bladder, and prostate cancers. The enhanced apoptosis induced by gemcitabine plus ABT-737 was accompanied by the greater extent of mitochondrial depolarization, caspases-3 activation, and PARP cleavage in 95-D and 5637 cell lines. Importantly, in ABT-737-resistant cancer cells, the interaction between USP9X and Mcl-1, which was increased by ABT-737 treatment, could be disrupted by gemcitabine, thus resulting in enhanced ubiquitination and the subsequent degradation of Mcl-1 and ultimately in the synergism of these two drugs. Moreover, the increased anticancer efficacy of gemcitabine combined with ABT-737 was further validated in a human lung cancer 95-D xenograft model in nude mice. Taken together, our data first showed the synergistic anticancer capabilities achieved by combining gemcitabine and ABT-737 and, second, opened new opportunities to use antiapoptotic Bcl-2 family members, which drive tumor cell resistance in current anticancer therapies, therapeutically.

Topics: Animals; Antineoplastic Agents; Apoptosis; bcl-2-Associated X Protein; Biphenyl Compounds; Caspases; Cell Line, Tumor; Cell Proliferation; Deoxycytidine; Drug Synergism; Gemcitabine; Humans; Membrane Potential, Mitochondrial; Mice; Mice, Nude; Myeloid Cell Leukemia Sequence 1 Protein; Neoplasms; Nitrophenols; Piperazines; Protein Binding; Proto-Oncogene Proteins c-bcl-2; RNA Interference; Sulfonamides; Ubiquitin Thiolesterase; Xenograft Model Antitumor Assays

As single agents, ABT-263 and ABT-737 (ABT), molecular antagonists of the Bcl-2 family, bind tightly to Bcl-2, Bcl-xL and Bcl-w, but not to Mcl-1, and induce apoptosis only in limited cell types. The compound 2-deoxyglucose (2DG), in contrast, partially blocks glycolysis, slowing cell growth but rarely causing cell death. Injected into an animal, 2DG accumulates predominantly in tumors but does not harm other tissues. However, when cells that were highly resistant to ABT were pre-treated with 2DG for 3 hours, ABT became a potent inducer of apoptosis, rapidly releasing cytochrome c from the mitochondria and activating caspases at submicromolar concentrations in a Bak/Bax-dependent manner. Bak is normally sequestered in complexes with Mcl-1 and Bcl-xL. 2DG primes cells by interfering with Bak-Mcl-1 association, making it easier for ABT to dissociate Bak from Bcl-xL, freeing Bak to induce apoptosis. A highly active glucose transporter and Bid, as an agent of the mitochondrial apoptotic signal amplification loop, are necessary for efficient apoptosis induction in this system. This combination treatment of cancer-bearing mice was very effective against tumor xenograft from hormone-independent highly metastasized chemo-resistant human prostate cancer cells, suggesting that the combination treatment may provide a safe and effective alternative to genotoxin-based cancer therapies.

Topics: Aniline Compounds; Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Biphenyl Compounds; Blotting, Western; Cell Line, Tumor; Cytochromes c; Deoxyglucose; Dose-Response Relationship, Drug; HeLa Cells; Hep G2 Cells; Humans; Male; Mice; Mice, Knockout; Mice, Nude; Mitochondria; Myeloid Cell Leukemia Sequence 1 Protein; Neoplasms; Nitrophenols; Piperazines; Proto-Oncogene Proteins c-bcl-2; Sulfonamides; Survival Analysis; Tumor Burden; Xenograft Model Antitumor Assays

MCL1 is essential for the survival of stem and progenitor cells of multiple lineages, and is unique among pro-survival BCL2 family members in that it is rapidly turned over through the action of ubiquitin ligases. B- and mantle-cell lymphomas, chronic myeloid leukaemia, and multiple myeloma, however, express abnormally high levels of MCL1, contributing to chemoresistance and disease relapse. The mechanism of MCL1 overexpression in cancer is not well understood. Here we show that the deubiquitinase USP9X stabilizes MCL1 and thereby promotes cell survival. USP9X binds MCL1 and removes the Lys 48-linked polyubiquitin chains that normally mark MCL1 for proteasomal degradation. Increased USP9X expression correlates with increased MCL1 protein in human follicular lymphomas and diffuse large B-cell lymphomas. Moreover, patients with multiple myeloma overexpressing USP9X have a poor prognosis. Knockdown of USP9X increases MCL1 polyubiquitination, which enhances MCL1 turnover and cell killing by the BH3 mimetic ABT-737. These results identify USP9X as a prognostic and therapeutic target, and they show that deubiquitinases may stabilize labile oncoproteins in human malignancies.

Topics: Animals; Apoptosis; Biphenyl Compounds; Cell Line; Cell Line, Tumor; Cell Survival; DNA Damage; Docetaxel; Etoposide; Female; Gene Expression Regulation, Neoplastic; Gene Knockdown Techniques; Half-Life; Humans; Lysine; Mice; Mice, SCID; Myeloid Cell Leukemia Sequence 1 Protein; Neoplasms; Nitrophenols; Phosphorylation; Piperazines; Polyubiquitin; Prognosis; Protein Binding; Protein Stability; Proto-Oncogene Proteins c-bcl-2; RNA Interference; Sulfonamides; Taxoids; Ubiquitin Thiolesterase; Ubiquitination; Ultraviolet Rays; Xenograft Model Antitumor Assays

Pseudomonas exotoxin (PE)-based immunotoxins (antibody-toxin fusion proteins) have achieved frequent complete remissions in patients with hairy cell leukemia but far fewer objective responses in other cancers. To address possible mechanisms of resistance, we investigated immunotoxin activity in a model system using the colon cancer cell line, DLD1. Despite causing complete inhibition of protein synthesis, there was no evidence that an immunotoxin targeted to the transferrin receptor caused apoptosis in these cells. To address a possible protective role of prosurvival Bcl-2 proteins, the BH3-only mimetic, ABT-737, was tested alone or in combination with immunotoxins. Neither the immunotoxin nor ABT-737 alone activated caspase 3, whereas the combination exhibited substantial activation. In other epithelial cell lines, ABT-737 enhanced the cytotoxicity of PE-related immunotoxins by as much as 20-fold, but did not enhance diphtheria toxin or cycloheximide. Because PE translocates to the cytosol via the endoplasmic reticulum (ER) and the other toxins do not, ABT-737-mediated effects on the ER were investigated. ABT-737 treatment stimulated increased levels of ER stress response factor, ATF4. Because of its activity in the ER, ABT-737 might be particularly well suited for enhancing the activity of immunotoxins that translocate from the ER to the cell cytosol.

Topics: Activating Transcription Factor 4; Apoptosis; Biphenyl Compounds; Blotting, Western; Caspases; Cell Line, Tumor; Cell Survival; Cytosol; Dose-Response Relationship, Drug; Drug Resistance, Neoplasm; Drug Synergism; Endoplasmic Reticulum; Exotoxins; Humans; Immunotoxins; Neoplasms; Nitrophenols; Piperazines; Protein Biosynthesis; Proto-Oncogene Proteins c-bcl-2; Pseudomonas; Sulfonamides

Topics: Aniline Compounds; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; bcl-2 Homologous Antagonist-Killer Protein; bcl-2-Associated X Protein; Biphenyl Compounds; Dactinomycin; Drug Synergism; Humans; Myeloid Cell Leukemia Sequence 1 Protein; Neoplasms; Nitrophenols; Peptide Fragments; Piperazines; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Sulfonamides

Topics: Animals; BH3 Interacting Domain Death Agonist Protein; Biphenyl Compounds; Humans; Mitochondria; Neoplasms; Nitrophenols; Piperazines; Proto-Oncogene Proteins c-bcl-2; Sulfonamides; Translational Research, Biomedical

Because Bcl-2 family members inhibit the ability of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) to induce apoptosis, we investigated whether ABT-737, a small molecule Bcl-2 inhibitor, enhances TRAIL killing. We demonstrate that a combination of ABT-737 and TRAIL induced significant cell death in multiple cancer types, including renal, prostate, and lung cancers, although each agent individually had little activity in these tumor cells. All of these cell lines expressed the Mcl-1 protein that is known to block the activity of ABT-737 and TRAIL but did not block the synergy between these agents. However, Bax-deficient cell lines, including DU145 and HCT116 cells and those cell lines expressing low levels of TRAIL receptor, were resistant to apoptosis induced by these agents. To understand how ABT-737 functions to markedly increase TRAIL sensitivity, the levels of specific death-inducing signaling complex components were evaluated. Treatment with ABT-737 did not change the levels of c-FLIP, FADD, and caspase-8 but up-regulated the levels of the TRAIL receptor DR5. DR5 up-regulation induced by ABT-737 treatment occurred through a transcriptional mechanism, and mutagenesis studies demonstrated that the NF-kappaB site found in the DR5 promoter was essential for the ability of ABT-737 to increase the levels of this mRNA. Using luciferase reporter plasmids, ABT-737 was shown to stimulate NF-kappaB activity. Together, these results demonstrate that the ability of ABT-737 and TRAIL to induce apoptosis is mediated through activation of both the extrinsic and intrinsic pathways. Combinations of ABT-737 and TRAIL can be exploited therapeutically where antiapoptotic Bcl-2 family members drive tumor cell resistance to current anticancer therapies.

Topics: Antineoplastic Agents; Apoptosis; Biphenyl Compounds; CASP8 and FADD-Like Apoptosis Regulating Protein; Caspase 8; Cell Line, Tumor; Drug Screening Assays, Antitumor; Fas-Associated Death Domain Protein; Humans; Mutagenesis; Myeloid Cell Leukemia Sequence 1 Protein; Neoplasms; NF-kappa B; Nitrophenols; Piperazines; Proto-Oncogene Proteins c-bcl-2; Receptors, TNF-Related Apoptosis-Inducing Ligand; Response Elements; Sulfonamides; TNF-Related Apoptosis-Inducing Ligand; Up-Regulation

The ability to selectively induce a strong immune response against self-proteins, or increase the immunogenicity of specific epitopes in foreign antigens, would have a significant impact on the production of vaccines for cancer, protein-misfolding diseases, and infectious diseases. Here, we show that site-specific incorporation of an immunogenic unnatural amino acid into a protein of interest produces high-titer antibodies that cross-react with WT protein. Specifically, mutation of a single tyrosine residue (Tyr(86)) of murine tumor necrosis factor-alpha (mTNF-alpha) to p-nitrophenylalanine (pNO(2)Phe) induced a high-titer antibody response in mice, whereas no significant antibody response was observed for a Tyr(86) --> Phe mutant. The antibodies generated against the pNO(2)Phe are highly cross-reactive with native mTNF-alpha and protect mice against lipopolysaccharide (LPS)-induced death. This approach may provide a general method for inducing an antibody response to specific epitopes of self- and foreign antigens that lead to a neutralizing immune response.

Topics: Amino Acid Substitution; Animals; Antibody Formation; Communicable Diseases; Endotoxemia; Epitopes; Immunochemistry; Lipopolysaccharides; Male; Metabolic Diseases; Mice; Mutation, Missense; Neoplasms; Nitrophenols; Self Tolerance; Tumor Necrosis Factor-alpha; Vaccines

B-RAF is frequently mutated in solid tumors, resulting in activation of the MEK/ERK signaling pathway and ultimately tumor cell growth and survival. MEK inhibition in these cells results in cell cycle arrest and cytostasis. Here, we have shown that MEK inhibition also triggers limited apoptosis of human tumor cell lines with B-RAF mutations and that this effect was dependent on upregulation and dephosphorylation of the proapoptotic, Bcl-2 homology 3-only (BH3-only) Bcl-2 family member Bim. However, upregulation of Bim was insufficient for extensive apoptosis and was countered by overexpression of Bcl-2. To overcome apoptotic resistance, we treated the B-RAF mutant cells both with MEK inhibitors and with the BH3 mimetic ABT-737, resulting in profound synergism and extensive tumor cell death. This treatment was successful because of both efficient antagonism of the prosurvival Bcl-2 family member Mcl-1 by Bim and inhibition of Bcl-2 and Bcl-x(L) by ABT-737. Critically, addition of ABT-737 converted the predominantly cytostatic effect of MEK inhibition to a cytotoxic effect, causing long-term tumor regression in mice xenografted with human tumor cell lines. Thus, the therapeutic efficacy of MEK inhibition requires concurrent unleashing of apoptosis by a BH3 mimetic and represents a potent combination treatment for tumors harboring B-RAF mutations.

Topics: Apoptosis Regulatory Proteins; Bcl-2-Like Protein 11; Biphenyl Compounds; Cell Line, Tumor; HT29 Cells; Humans; Membrane Proteins; Mitogen-Activated Protein Kinase Kinases; Molecular Mimicry; Mutation; Neoplasms; Nitrophenols; Piperazines; Proto-Oncogene Proteins; Proto-Oncogene Proteins B-raf; Proto-Oncogene Proteins c-bcl-2; Sulfonamides

Topics: Antineoplastic Agents; Biphenyl Compounds; Genes, bcl-2; Humans; Neoplasms; Nitrophenols; Piperazines; Proto-Oncogene Proteins c-bcl-2; Sulfonamides

In this issue of Cancer Cell, two groups present data on the function of an antagonist of BCL-2, ABT-737. Both groups find that expression of MCL-1, an antiapoptotic protein related to BCL-2, is a key determinant of resistance to ABT-737. Lowering MCL-1 levels is an effective adjunct to BCL-2 antagonism, and both groups suggest ways that this might be accomplished practically in a clinical setting. The mechanism by which ABT-737 selectively kills cancer cells is discussed below in the context of these and prior reports of ABT-737's function. Antagonism of BCL-2 is an exciting anticancer strategy that may soon become a clinical reality.

Topics: Animals; bcl-2 Homologous Antagonist-Killer Protein; bcl-2-Associated X Protein; Biphenyl Compounds; Humans; Myeloid Cell Leukemia Sequence 1 Protein; Neoplasm Proteins; Neoplasms; Nitrophenols; Piperazines; Proto-Oncogene Proteins c-bcl-2; Sulfonamides

Proteins in the Bcl-2 family are central regulators of programmed cell death, and members that inhibit apoptosis, such as Bcl-X(L) and Bcl-2, are overexpressed in many cancers and contribute to tumour initiation, progression and resistance to therapy. Bcl-X(L) expression correlates with chemo-resistance of tumour cell lines, and reductions in Bcl-2 increase sensitivity to anticancer drugs and enhance in vivo survival. The development of inhibitors of these proteins as potential anti-cancer therapeutics has been previously explored, but obtaining potent small-molecule inhibitors has proved difficult owing to the necessity of targeting a protein-protein interaction. Here, using nuclear magnetic resonance (NMR)-based screening, parallel synthesis and structure-based design, we have discovered ABT-737, a small-molecule inhibitor of the anti-apoptotic proteins Bcl-2, Bcl-X(L) and Bcl-w, with an affinity two to three orders of magnitude more potent than previously reported compounds. Mechanistic studies reveal that ABT-737 does not directly initiate the apoptotic process, but enhances the effects of death signals, displaying synergistic cytotoxicity with chemotherapeutics and radiation. ABT-737 exhibits single-agent-mechanism-based killing of cells from lymphoma and small-cell lung carcinoma lines, as well as primary patient-derived cells, and in animal models, ABT-737 improves survival, causes regression of established tumours, and produces cures in a high percentage of the mice.

Topics: Animals; Antineoplastic Agents; Apoptosis; Biphenyl Compounds; Carcinoma, Small Cell; Cell Line, Tumor; Cytochromes c; Disease Models, Animal; Drug Synergism; Humans; Lymphoma; Magnetic Resonance Spectroscopy; Mice; Mitochondria; Models, Molecular; Neoplasms; Nitrophenols; Paclitaxel; Piperazines; Proto-Oncogene Proteins c-bcl-2; Structure-Activity Relationship; Sulfonamides; Survival Rate

Members of the BCL-2 family of proteins regulate and execute many cell intrinsic apoptosis pathways, including those arising from dysregulated expression of cellular oncogenes. Since pro-survival members of the family are often strongly elevated in diverse cancers, with the potential to confer resistance to both endogenous cell death stimuli and many cancer treatments, there has been intense interest to develop strategies to therapeutically modulate their activity. Although encouraging genetic and pharmacological preclinical proof of concept has been obtained, the challenge for clinical development will be to devise strategies that address the fact that multiple pro-survival members are typically up-regulated in a given cancer and the family operates primarily through protein-protein interactions. Moreover, since several current therapies themselves are known to stimulate the levels of one or more family members, there will be additional challenges (and opportunities) in exploiting this target in the clinic. In this review, we describe the rationale for targeting the BCL-2 family of apoptosis suppressors in cancer and the progress that has been made in modulating the family by small molecule antagonists.

Topics: Animals; Apoptosis; Biphenyl Compounds; Cell Line, Tumor; Cell Survival; Genes, myc; Humans; Indoles; Models, Animal; Neoplasms; Nitrophenols; Oncogenes; Piperazines; Proto-Oncogene Proteins c-bcl-2; Proto-Oncogene Proteins c-myc; Pyrroles; Sulfonamides

Topics: Animals; Antineoplastic Agents; Apoptosis; Biphenyl Compounds; Cytochromes c; Drugs, Investigational; Glycolysis; Hexanones; Humans; Mitochondria; Mitochondrial Proton-Translocating ATPases; Neoplasms; Nitrophenols; Piperazines; Proto-Oncogene Proteins c-bcl-2; Sulfonamides; Thionucleotides

The Bcl-2 protein family, which largely determines commitment to apoptosis, has central roles in tumorigenesis and chemoresistance. Its three factions of interacting proteins include the BH3-only proteins (e.g., Bim, Puma, Bad, Noxa), which transduce diverse cytotoxic signals to the mammalian pro-survival proteins (Bcl-2, Bcl-x(L), Bcl-w, Mcl-1, A-1), whereas Bax and Bak, when freed from pro-survival constraint, provoke the mitochondrial permeabilization that triggers apoptosis. We have discovered unexpected specificity in their interactions. Only Bim and Puma, which mediate multiple cytotoxic signals, engage all the pro-survival proteins. Noxa and Bad instead bind subsets and cooperate in killing, indicating that apoptosis requires neutralization of different pro-survival subsets. Furthermore, Mcl-1 and Bcl-x(L), but not Bcl-2, directly sequester Bak in healthy cells, and Bak is freed only when BH3-only proteins neutralize both its guards. BH3-only proteins such as Bim are tumor suppressors and mediate many of the cytotoxic signals from anticancer agents. Hence, compounds mimicking them may prove valuable for therapy. Indeed, the recently described ABT-737 is a promising "BH3 mimetic" of Bad. We find that, like Bad, ABT-737 kills cells efficiently only if Mcl-1 is absent or down-regulated. Thus, manipulation of apoptosis by targeting the Bcl-2 family has exciting potential for cancer treatment.

Topics: Animals; Antineoplastic Agents; Apoptosis; Biphenyl Compounds; Drug Design; Genes, bcl-2; Humans; Models, Biological; Molecular Mimicry; Neoplasms; Nitrophenols; Piperazines; Proto-Oncogene Proteins c-bcl-2; Signal Transduction; Sulfonamides

We developed a universal recombinant bispecific molecule (BiMol) that is capable of redirecting cytotoxic T cells to tumor cells via tagged anti-tumor ligands such as antibody fragments or cytokines. A recombinant bispecific diabody with binding specificities for the CD3 molecule on T cells as well as for the hapten nitrophenyl (NIP) was produced. This bispecific molecule is capable of redirecting cytotoxic T cells to kill a series of malignant cells, including B cell lymphoma, Hodgkin's lymphoma, and colon carcinoma via NIP-conjugated ligands to tumor-associated antigens. Cytotoxic activity of the diabody was found to be comparable to tetradoma-derived bispecific antibodies with similar specificities. Our findings demonstrate that universal CD3xanti-NIP diabodies could be used for T cell based cellular immunotherapy in a variety of human malignancies. Additionally, these bispecific molecules allow fast and economic testing of tumor-associated antigens on malignant cells for their potential use as immunotherapeutic target structures if corresponding hapten-conjugated antibodies or ligands are available.

Topics: Antibodies, Bispecific; Antigens, Neoplasm; Calcium; CD3 Complex; Cell Division; Haptens; Humans; Hybridomas; Jurkat Cells; Neoplasms; Nitrophenols; Phenylacetates; T-Lymphocytes, Cytotoxic; Tumor Cells, Cultured

A capture immunoenzyme assay (CIEA) for prostatic acid phosphatase (PAP) was developed and used to study the stability of this isoenzyme. Immunospecifically purified goat antibodies to PAP were covalently bound to special discs and used to capture the enzyme in serum samples in a weakly acidic medium during the first incubation (2 h) at 37 degrees C. The capture enzyme was then measured by its catalytic activity with p-nitrophenyl phosphate as substrate during the second incubation (1 h) at 37 degrees C. As much as 98% of the PAP in test specimens was captured and measured by this CIEA. The test results were expressed as enzymatic activity (U/l), extrapolated from a standard curve which was linear between 0.026 and 70 U/l. In test sera stored at 4 degrees C, the PAP was variably stable for 7 to 70 days, but the enzyme was quite stable in serum when stored at -20 degrees C for at least 156 days. At room temperature, when the sera were appropriately acidified, there was no loss of enzymatic activity for periods of 15 days, and in some cases, a large proportion of activity was still intact after 70 days. At 4 degrees C, as well as -20 degrees C, acidified serum and the partially purified PAP standard showed complete stability for at least 7 months. The CIEA reactivity of positive test specimens was inhibited by L(+)-tartaric acid, but not by cupric sulfate. The acid phosphatases of blood cell extracts were non-reactive in the CIEA procedure. The CIEA results of 224 serum samples from patients with and without prostate cancer correlated very well with those obtained by two direct enzymatic and two commercial RIA procedures, with correlation coefficients between 0.960 and 0.993, and diagnostic agreement between 86% and 100%.

Topics: Acid Phosphatase; Adult; Cold Temperature; Drug Stability; Female; Humans; Hydrogen-Ion Concentration; Immunoenzyme Techniques; Male; Neoplasms; Nitrophenols; Organophosphorus Compounds; Prostate; Prostatic Neoplasms; Serum Albumin, Bovine; Time Factors

The major forms of human serum hexosaminidases A and B (Hex A and Hex B) were isolated from normal subjects and cancer patients using DEAE-cellulose. In normal serum, Hex A was heat-labile and had an apparent KM of 1.13 mM and Vmax of 0.51 mumol/ml/h; Hex B was heat-stable and had an apparent KM of 0.85 mM and Vmax of 0.22 mumol/ml/h. Both forms had the same pH optimum, at 4.3. Hex A and Hex B from the sera of cancer patients resembled their normal counterparts in heat stability, pH optimum, and apparent KM (1.07 mM for Hex A, 0.88 mM for Hex B). In contrast, the Vmax values for the cancer sera isozymes were greater than those of normal sera (0.70 and 0.40 mumol/ml/h for Hex A and Hex B, respectively).

Topics: Hexosaminidases; Humans; Hydrogen-Ion Concentration; Kinetics; Methods; Neoplasms; Nitrophenols; Temperature; Time Factors

Topics: Animals; Cells, Cultured; Chromium Radioisotopes; Cytotoxicity Tests, Immunologic; Histocompatibility Antigens; Mice; Mice, Inbred C57BL; Mice, Inbred DBA; Mice, Inbred Strains; Neoplasms; Nitrophenols; Receptors, Antigen, B-Cell; Spleen; T-Lymphocytes

One hundred eighty-three patients with advanced solid neoplasms were tested for their ability to react to four common skin test antigens (tuberculin PPD, streptokinase-streptodornase, mumps, and Monilia) and their ability to develop delayed cutaneous hypersensitivity (DCH) to 2, 4 dinitrochlorobenzene (DNCB). All patients were followed for at least 6 months or until death. Histologic tumor types studied were: melanoma (65), sarcoma (28), squamous cell carcinoma (23), and adenocarcinoma (67). The rate of progression of disease within 6 months of testing was lower in patients who had a positive response to a challenging dose of 50 mug of DNCB. Reactivity to recall antigens had no prognostic value except in patients with adenocarcinomas. Among patients with adenocarcinoma, those who reacted strongly to DNCB and one or more skin test antigens had the best prognosis, while those who were nonreactive to all had the worst prognosis (progression rate: 18% vs. 78%). Peripheral lymphocyte counts were related to the results of DCH to DNCB and skin tests. The preseence or absence of lymphocytopenia (count less than 1000/mm3) had prognostic value in patients who had positive skin test(s). In such patients, the disease progression rate was much higher in patients who were anergic to DNCB and who were lymphocytopenic (90% vs. 40%). These data suggest that DCH to DNCB, recall antigens, and peripheral lymphocyte counts are useful immunologic measurements in patients with advanced cancer. Although the prognostic value of each individual test is relatively limited, the predictive worth can be increased when multiple tests are employed. Pertinent findings reported in the literature are reviewed.

Topics: Adenocarcinoma; Candida; Carcinoma, Squamous Cell; Humans; Hypersensitivity, Delayed; Immunity, Cellular; Leukocyte Count; Lymphocytes; Melanoma; Mumps virus; Neoplasms; Nitrophenols; Prognosis; Sarcoma; Skin Tests; Streptodornase and Streptokinase; Time Factors; Tuberculin Test

Topics: Adenosine Diphosphate; Adenosine Triphosphate; Animals; Glucose; Glucosephosphates; Glutamates; Glycolysis; Hexokinase; Malates; Mitochondria, Liver; Neoplasms; Nitrophenols; Oxidative Phosphorylation; Oxygen; Oxygen Consumption; Phosphoenolpyruvate; Phosphoric Acids; Polarography; Pyruvate Kinase; Pyruvates; Rats; Succinates

Interaction of microgram quantities of highly purified rabbit anti-TNP antibodies with TNP-substituted HeLa, HEp-2, and L cells caused an intense stimulation of radioactive nucleoside ([(125)I]UdR and [(3)H]TdR) uptake which was maximal 24-72 h after exposure of cells to antibody. The stimulation of nucleoside uptake and presumaly DNA synthesis was shown to be immuno logically mediated because unsubstituted cells were not stimulated by anti-TNP antibody, normal rabbit gamma globulin did not stimulate TNP-cells, and a hapten inhibitor, epsilon-DNP-lysine, prevented the stimulation of TNP-cells by anti-TNP antibody. These findings demonstrate that interaction of antibody with cell surface antigen can alter cell membrane transport, and possibly can enhance cell growth.

Topics: Animals; Antibodies; Carcinoma; Cell Line; Female; Glucose Oxidase; HeLa Cells; Humans; Idoxuridine; Iodides; Iodine Radioisotopes; Kinetics; L Cells; Laryngeal Neoplasms; Mice; Neoplasms; Nitrophenols; Peroxidases; Thymidine; Tritium; Trypsin

Tumor cell lines exposed to immunoglobulins specific for cell surface antigens developed increased cellular incorporation of [(125)I]iododeoxyuridine and [(3)H]thymidine (up to 200-fold increases over cells treated with normal rabbit immunoglobulins). Antibody-stimulated cells multiplied more rapidly and lived longer than control cells in tissue culture. These observations were made both with cells substituted with 2,4,6-trinitrophenol and purified antibody against 2,4,6-trinitrophenol, and with several cell lines and their respective whole-cell antibodies. Antibodies that were stimulatory at low concentrations were cytotoxic at high concentrations. These observations may have significance in regard to enhancing effects of antibodies on tumor cell growth in vivo.

Topics: Animals; Antibodies, Neoplasm; Carcinoma; Cell Line; Colonic Neoplasms; Cross Reactions; DNA, Neoplasm; Epitopes; Female; HeLa Cells; Humans; Idoxuridine; Iodine Radioisotopes; Laryngeal Neoplasms; Mice; Neoplasms; Nitrophenols; Plasmacytoma; Rabbits; Thymidine; Tritium

Topics: Antibodies, Neoplasm; Antineoplastic Agents; Cytotoxicity Tests, Immunologic; Glucose Oxidase; Haptens; HeLa Cells; Iodine Isotopes; Isotope Labeling; Microscopy, Phase-Contrast; Neoplasms; Nitrophenols; Peroxidases

Topics: Adult; Child; Diabetes Mellitus; Enzymes; Female; Genetics, Medical; Glucuronidase; Humans; Hydrogen-Ion Concentration; Lactones; Liver Cirrhosis; Male; Neoplasms; Nitrophenols; Phenolphthaleins; Pregnancy; Quinolines

Topics: Alkaline Phosphatase; Histocytochemistry; Hydrocortisone; Neoplasms; Nitrophenols; Pharmacology; Research; Spectrophotometry; Tissue Culture Techniques

Topics: 2,4-Dinitrophenol; Ascites; Carcinoma, Hepatocellular; Dinitrophenols; Liver; Liver Neoplasms; Metabolism; Neoplasms; Neoplasms, Experimental; Nitrophenols

Topics: Amino Acids; Animals; Ascites; Azides; Cyanides; Iodoacetates; Malonates; Neoplasms; Nitrophenols; Organic Chemicals; Phenylalanine; Sarcoma; Sarcoma 37; Sarcoma, Experimental; Tyrosine

Topics: Animals; Antineoplastic Agents; Neoplasms; Nitrophenols; Rats; Uncoupling Agents

Topics: Ascites; Dinitrophenols; Fatty Acids; Neoplasms; Nitrophenols; Phosphorus

Topics: 2,4-Dinitrophenol; Animals; Carbohydrate Metabolism; Carcinoma, Ehrlich Tumor; Hexoses; Neoplasms; Nitrophenols; Sodium Azide

Topics: Biochemical Phenomena; Dinitrophenols; In Vitro Techniques; Mitochondria; Neoplasms; Nitrophenols; Phosphorus

Topics: Adenine Nucleotides; Adenosine Triphosphate; Ascites; Carbohydrate Metabolism; Carbohydrates; Dinitrophenols; Glycolysis; Neoplasms; Nitrophenols; Phosphates

Topics: Ascites; Dinitrophenols; Neoplasms; Nitrophenols

Topics: Ascites; Dinitrophenols; Fatty Acids; Glucose; Humans; Lipid Metabolism; Neoplasms; Nitrophenols; Oxidation-Reduction

Topics: Animals; Carbohydrate Metabolism; Carbohydrates; Carcinoma, Ehrlich Tumor; Cell Respiration; Glycolysis; Iodoacetates; Neoplasms; Nitrophenols; Respiration

Topics: Antimetabolites; Humans; In Vitro Techniques; Neoplasms; Nitrophenols

Topics: Azides; Cell Respiration; Iodoacetates; Neoplasms; Nitrophenols

Topics: 2,4-Dinitrophenol; Ergot Alkaloids; In Vitro Techniques; Metabolism; Neoplasms; Nitrophenols

Topics: Animals; Dinitrophenols; Mice; Neoplasms; Nitrophenols; Succinates; Succinic Acid

Topics: Dinitrophenols; Fluorides; Glucose; Humans; Neoplasms; Nitrophenols; Oxidation-Reduction; Phosphates

Topics: Animals; Carcinoma, Ehrlich Tumor; Cell Division; Dinitrophenols; Neoplasms; Nitrophenols

Topics: Dinitrophenols; Fluorides; Humans; Neoplasms; Nitrophenols; Oxidation-Reduction; Phosphates