aq4n and Hypoxia

Hypoxia, or a lack of oxygen, occurs in 50-60% of solid human tumours. Clinical studies have shown that the presence and extent of hypoxia in a tumour cannot be predicted by size or histopathological stage but it is predictive of a poor outcome following radiotherapy, chemotherapy and surgery. However, as a physiological feature of tumours, it can be exploited and researchers have developed many hypoxia-selective chemotherapies or bioreductive drugs that are in varying stages of clinical development. These agents are prodrugs that have two key requirements for their biological activation: they require the reductive environment of a hypoxic tumour cell and the appropriate complement of cellular reductase enzymes. To overcome tumour heterogeneity in reductase enzyme levels and enhance bioreductive drug metabolism a gene therapy strategy can be employed. We have reviewed this field and also present our own pre-clinical research using gene therapy to enhance bioreductive drug treatment for the treatment of cancer. We have specifically focused on studies enhancing lead clinical bioreductive drugs. We consider the metabolic requirements for their activation and we highlight the key in vivo studies supporting the future clinical development of hypoxia-targeted gene-directed enzyme prodrug therapy.

Topics: Alkylating Agents; Animals; Anthraquinones; Breast Neoplasms; Cytochrome P-450 Enzyme System; Cytochromes; Cytochromes b5; Female; Genetic Therapy; Humans; Hypoxia; Hypoxia-Inducible Factor 1; Mice; Mitomycin; Neoplasms; Nitric Oxide Synthase; Prodrugs; Xanthine Oxidase

Banoxantrone is a topoisomerase II inhibitor that is selectively activated in hypoxia. Although it has exhibited anti-tumor activity against several types of cancers in preclinical models, its efficacy against colorectal cancer (CRC) remains unclear.. We examined the antitumor effects of 1,4-bis[2-(dimethylamino)ethylamino]-5,8-dihydroxyanthracene-9,10-dione (AQ4), an activated metabolite of banoxantrone, in CRC cell lines (HT-29, CaR-1) using in vitro experiments under normoxic and hypoxic conditions. The inhibition of cell growth was assessed using a proliferation assay. The induction of apoptosis and changes in the cell cycle were measured using flow cytometry. Signaling pathways involved in apoptosis and hypoxia were analyzed. The anti-tumor activity of temsirolimus, an inhibitor of mammalian target of rapamycin, and the combined effects of temsirolimus and AQ4 were also evaluated.. Regardless of the oxygen condition, a single drug treatment with AQ4 or temsirolimus inhibited proliferation and induced apoptosis in both cell lines, accompanied by a reduction in the phosphorylation of S6. AQ4 induced G2/M cell cycle arrest, whereas temsirolimus induced G0/G1 arrest. Moreover, the combined treatment markedly reduced the proportion of cells in the S phase and enhanced apoptosis, as evidenced by an increased Bax/Bcl-2 ratio. The hypoxia-induced activation of the HIF-1α pathway was suppressed by AQ4 and temsirolimus.. Based on the cooperative anti-tumor activity of AQ4 and temsirolimus in vitro, the combination of banoxantrone plus temsirolimus has potential as a treatment option for CRC in preclinical and clinical settings.

Topics: Apoptosis; Cell Line, Tumor; Cell Proliferation; Colorectal Neoplasms; Humans; Hypoxia

In recent years, laser-mediated photodynamic therapy and photothermal therapy have attracted widespread attention due to their minimally invasive, easy to operate characteristics and high specificity. However, the traditional photodynamic or photothermal therapy exist several shortcomings such as the hypoxic microenvironment, intracellular heat shock proteins or complex operation. In this study, covalent organic framework (COF) was used as the drug carrier to equip with the photosensitizer indocyanine green (ICG) and the hypoxia-activating prodrug AQ4N. The hyaluronic acid (HA) was modified on the surface of COF to obtain the HA-COF@ICG/AQ4N drug delivery system. HA-modified COF delivery systems can target tumor cells through recognize CD44 which is overexpressed in the surface of tumor cells membrane. Under the irradiation of single NIR laser, ICG that can excite the nanoplatform simultaneously produces a combined effect of photodynamic and photothermal. At the same time, photodynamic therapy through depleting intracellular oxygen exacerbates the hypoxic state of the tumor microenvironment, which in turn enhances AQ4N reduced to chemotherapeutic drug AQ4, producing a synergistic cascade antitumor effect. The results of our study by tumor cell and tumor spheroids indicated that the hypoxia-activated multi-functional nanoplatform could effectively inhibit the growth and metastasis of triple-negative breast cancer.

Topics: Cell Line, Tumor; Humans; Hypoxia; Indocyanine Green; Infrared Rays; Metal-Organic Frameworks; Nanoparticles; Photochemotherapy; Photosensitizing Agents; Triple Negative Breast Neoplasms; Tumor Microenvironment

Using nanotechnology to improve the efficiency of tumor treatment represents a major research interest in recent years. However, there are paradoxes and obstacles in using a single nanoparticle to fulfill all the requirements of complex tumor treatment.. In this paper, a programmed-triggered nanoplatform (APP NPs), which is sequentially responsive to light and hypoxia, is rationally integrated for photoacoustic (PA) imaging-guided synergistic cancer photo-chemotherapy. The nanoplatform is constructed by in situ hybridization of dopamine monomer in the skeleton of PCN-224 and loading prodrug banoxantrone (AQ4N). Upon first-stage irradiation with a 660 nm laser, cellular internalization was effectively promoted by a photosensitizer-mediated photochemical effect. Furthermore, under second-stage irradiation, APP NPs exhibit a notably high photothermal conversion efficiency and sufficient reactive oxygen species (ROS) production for photothermal therapy (PTT) and photodynamic therapy (PDT), respectively, which not only triggers rapid intercellular drug release but also consequently aggravates tumor hypoxia levels, and aggravated hypoxia can further active the cytotoxicity of AQ4N for chemotherapy. Both in vitro and in vivo studies confirm that the dual-stage light guided photo-chemotherapy strategy exhibits a greatly enhanced anticancer effects and superior therapeutic safety.. This work represents a versatile strategy to construct a dual-stage light induced PDT/PTT and hypoxia-activated chemotherapy nanoplatform and will be promising for the development of multistimuli-responsive nanosystems with programmable functions for precise cancer therapy.

Topics: Cell Line, Tumor; Humans; Hypoxia; Nanoparticles; Neoplasms; Photochemotherapy; Photosensitizing Agents

Since the hypoxia tumor microenvironment (TME) will not only limit the treatment effect but also cause tumor recurrence and metastasis, intratumoral aggravated hypoxia level induced by vascular embolization is one of the major challenges in tumor therapy. The chemotherapeutic effect of hypoxia-activated prodrugs (HAPs) could be enhanced by the intensified hypoxia, the combination of tumor embolization and HAP-based chemotherapy exhibits a promising strategy for cancer therapy. Herein, an acidity-responsive nanoplatform (TACC NP) with multiple pathways to benefit the hypoxia-activated chemotherapy is constructed by loading the photosensitizer Chlorin e6 (Ce6), thrombin (Thr), and AQ4N within the calcium phosphate nanocarrier via a simple one-pot method. In the acidic TME, TACC NPs could be degraded to release Thr and Ce6, resulting in the destruction of tumor vessels and consumption of intratumoral oxygen under laser irradiation. Therefore, the intratumoral hypoxia level could be significantly aggravated, further leading to the enhanced chemotherapeutic effect of AQ4N. With the guidance of in vivo fluorescence imaging, the TACC NPs exhibited excellent tumor embolization/photodynamic/prodrug synergistic therapeutic effects with good biosafety.

Topics: Cell Line, Tumor; Humans; Hypoxia; Nanoparticles; Neoplasm Recurrence, Local; Photochemotherapy; Photosensitizing Agents; Prodrugs; Tumor Hypoxia; Tumor Microenvironment

Triple-negative breast cancer (TNBC) possesses special biological behavior and clinicopathological characteristics, which is highly invasive and propensity to metastasize to lymph nodes, leading to a worse prognosis than other types of breast cancer. Thus, the development of an effective therapeutic method is significant to improve the survival rate of TNBC patients.. In this work, a liposome-based theranostic nanosystem (ILA@Lip) was successfully prepared by simultaneously encapsulating IR 780 as the photosensitizer and lenvatinib as an anti-angiogenic agent, together with banoxantrone (AQ4N) molecule as the hypoxia-activated prodrug. The ILA@Lip can be applied for the near-infrared (NIR) fluorescence diagnostic imaging of TNBC and its lymph node metastasis for multimodal therapy. Lenvatinib in ILA@Lip can inhibit angiogenesis by cutting oxygen supply, thereby leading to enhanced hypoxia levels. Meanwhile, large amounts of reactive oxygen species (ROS) were produced while IR 780 was irradiated by an 808 nm laser, which also rapidly exhausted oxygen in tumor cells to worsen tumor hypoxia. Through creating an extremely hypoxic in TNBC, the conversion of non-toxic AQ4N to toxic AQ4 was much more efficiency for hypoxia-activated chemotherapy. Cytotoxicity assay of ILA@Lip indicated excellent biocompatibility with normal cells and tissues, but showed high toxicity in hypoxic breast cancer cells. Also, the in vivo tumors treated by the ILA@Lip with laser irradiation were admirably suppressed in both subcutaneous tumor model and orthotopic tumor models.. Utilizing ILA@Lip is a profound strategy to create an extremely hypoxic tumor microenvironment for higher therapeutic efficacy of hypoxia-activated chemotherapy, which realized collective suppression of tumor growth and has promising potential for clinical translation.

Topics: Humans; Hypoxia; Lymphatic Metastasis; Optical Imaging; Oxygen; Triple Negative Breast Neoplasms; Tumor Microenvironment

Topics: Animals; Anthraquinones; Antineoplastic Agents; Aptamers, Nucleotide; Carcinoma, Hepatocellular; Copper; Disease Models, Animal; Drug Carriers; Gold; Hep G2 Cells; Heterografts; Humans; Hyperthermia, Induced; Hypoxia; Mice, Inbred BALB C; Mice, Nude; Nanoparticles; Photochemotherapy; Prodrugs; Treatment Outcome

Complications associated with the development of lung metastases have a detrimental effect on the overall survival rate of many cancer patients. Preclinical models that mimic the clinical aspects of lung metastases are an important tool in developing new therapy options for these patients. The commonly used intravenous models only recapitulate dissemination of cancer cells to the lungs via the haematological route. Here we compared spontaneous and intravenous lung metastases of the highly metastatic KHT mouse fibrosarcoma cells after injecting KHT cells into the subcutaneous layer of the skin or directly into the tail vein. In contrast to the intravenous model, metastases spontaneously arising from the subcutaneous tumours disseminated most consistent with the lymph nodes/lymphatics route and were more hypoxic than the metastases observed following tail-vein administration and haematological spread. To ascertain whether this impacted on drug response, we tested the effectiveness of the hypoxia-sensitive cytotoxin AQ4N (Banoxantrone) in both models. AQ4N was more effective as an anti-metastatic drug in mice with subcutaneous KHT tumours, significantly reducing the metastatic score. Complementing the KHT studies, pathology studies in additional models of spontaneous lung metastases showed haematological (HCT116 intrasplenic implant) or mixed haematological/lymphatic (B16 intradermal implant) spread. These data suggest that preclinical models can demonstrate differing, clinically relevant dissemination patterns, and that careful selection of preclinical models is required when evaluating new strategies for targeting metastatic disease.

Topics: Animals; Anthraquinones; Colorectal Neoplasms; Female; Fibrosarcoma; Humans; Hypoxia; Immunoenzyme Techniques; Lung Neoplasms; Lymph Nodes; Lymphatic Metastasis; Lymphatic Vessels; Melanoma, Experimental; Mice; Mice, Inbred C3H; Sarcoma, Experimental; Tumor Cells, Cultured

AQ4N [1,4-bis{[2-(dimethylamino-N-oxide)ethyl]amino}-5,8-dihydroxyanthracene-9,10-dione], a prodrug with two dimethylamino N-oxide groups, is converted to the topoisomerase II inhibitor AQ4 [1,4-bis{[2-(dimethylamino)ethyl]amino}-5,8-dihydroxy-anthracene-9,10-dione] by reduction of the N-oxides to dimethylamino substituents. Earlier studies showed that several drug-metabolizing cytochrome P450 (P450) enzymes can catalyze this reductive reaction under hypoxic conditions comparable with those in solid tumors. CYP2S1 and CYP2W1, two extrahepatic P450 enzymes identified from the human genome whose functions are unknown, are expressed in hypoxic tumor cells at much higher levels than in normal tissue. Here, we demonstrate that CYP2S1, contrary to a published report (Mol Pharmacol 76:1031-1043, 2009), is efficiently reduced by NADPH-P450 reductase. Most importantly, both CYP2S1 and CYP2W1 are better catalysts for the reductive activation of AQ4N to AQ4 than all previously examined P450 enzymes. The overexpression of CYP2S1 and CYP2W1 in tumor tissues, together with their high catalytic activities for AQ4N activation, suggests that they may be exploited for the localized activation of anticancer prodrugs.

Topics: Anthraquinones; Antineoplastic Agents; Cytochrome P-450 Enzyme System; Enzyme Inhibitors; Humans; Hypoxia; NADPH-Ferrihemoprotein Reductase; Neoplasms; Oxides; Prodrugs

AQ4N (banoxantrone) is a prodrug that, under hypoxic conditions, is enzymatically converted to a cytotoxic DNA-binding agent, AQ4. Incorporation of AQ4N into conventional chemoradiation protocols therefore targets both oxygenated and hypoxic regions of tumors, and potentially will increase the effectiveness of therapy. This current pharmacodynamic and efficacy study was designed to quantify tumor exposure to AQ4 following treatment with AQ4N, and to relate exposure to outcome of treatment. A single dose of 60 mg/kg AQ4N enhanced the response of RT112 (bladder) and Calu-6 (lung) xenografts to treatment with cisplatin and radiation therapy. AQ4N was also given to separate cohorts of tumor-bearing mice 24 hours before tumor excision for subsequent analysis of metabolite levels. AQ4 was detected by high performance liquid chromatography/mass spectrometry in all treated samples of RT112 and Calu-6 tumors at mean concentrations of 0.23 and 1.07 microg/g, respectively. These concentrations are comparable with those shown to be cytotoxic in vitro. AQ4-related nuclear fluorescence was observed in all treated tumors by confocal microscopy, which correlated with the high performance liquid chromatography/mass spectrometry data. The presence of the hypoxic marker Glut-1 was shown by immunohistochemistry in both Calu-6 tumors and RT112 tumors, and colocalization of AQ4 fluorescence and Glut-1 staining strongly suggested that AQ4N was activated in these putatively hypoxic areas. This is the first demonstration that AQ4N will increase the efficacy of chemoradiotherapy in preclinical models; the intratumoral levels of AQ4 found in this study are comparable with tumor AQ4 levels found in a recent phase I clinical study, which suggests that these levels could be potentially therapeutic.

Topics: Animals; Anthraquinones; Antineoplastic Agents; Cell Line, Tumor; Chromatography, High Pressure Liquid; Cisplatin; Combined Modality Therapy; Cytotoxins; Drug Synergism; Female; Humans; Hypoxia; Mass Spectrometry; Mice; Mice, Nude; Microscopy, Confocal; Neoplasms; Prodrugs; Radiotherapy; Treatment Outcome; Xenograft Model Antitumor Assays