cytochrome-c-t and Carcinogenesis

Cancer is a disease characterized by a very little apoptosis, ie, genetically programmed cell death. Aberrations in apoptotic pathways are central to tumorigenesis, tumor progression, and overall tumor growth and regression in response to chemotherapy. It is now increasingly accepted that chemotherapeutic drug efficacy is partially related to its ability to induce apoptosis. Apoptosis, therefore, represents not only a vital target in cancer therapy but also a unique biomarker opportunity that has thus far been largely unexploited. In response to therapy, tumor cells undergo apoptosis and release their cellular components in the circulation. As such, these materials may serve as biomarkers to assess response. Apoptosis markers in breast cancer include circulating soluble FasL, granzyme B, and cytochrome c that increase following chemotherapy. Unfortunately, there is a paucity of information in the literature with respect to this approach. As such, large-scale prospective studies are clearly needed to validate this approach and more fully elucidate clinical usefulness.

Topics: Antineoplastic Agents; Apoptosis; Biomarkers, Tumor; Breast Neoplasms; Carcinogenesis; Cytochromes c; Disease Progression; Fas Ligand Protein; Female; Gene Expression Regulation, Neoplastic; Granzymes; Humans; Neoplasm Proteins; Signal Transduction

Barrett's esophagus (BE) is associated with reflux and is implicated the development of esophageal adenocarcinoma (EAC). Apoptosis induces cell death through mitochondrial outer membrane permeabilization (MOMP), which is considered an irreversible step in apoptosis. Activation of MOMP to levels that fail to reach the apoptotic threshold may paradoxically promote cancer-a phenomenon called "Minority MOMP." We asked whether reflux-induced esophageal carcinogenesis occurred via minority MOMP and whether compensatory resistance mechanisms prevented cell death during this process. We exposed preneoplastic, hTERT-immortalized Barrett's cell, CP-C and CP-A, to the oncogenic bile acid, deoxycholic acid (DCA), for 1 year. Induction of minority MOMP was tested via comet assay, CyQuant, annexin V, JC-1, cytochrome C subcellular localization, caspase 3 activation, and immunoblots. We used bcl-2 homology domain-3 (BH3) profiling to test the mitochondrial apoptotic threshold. One-year exposure of Barrett's cells to DCA induced a malignant phenotype noted by clone and tumor formation. DCA promoted minority MOMP noted by minimal release of cytochrome C and limited caspase 3 activation, which resulted in DNA damage without apoptosis. Upregulation of the antiapoptotic protein, Mcl-1, ROS generation, and NF-κB activation occurred in conjunction with minority MOMP. Inhibition of ROS blocked minority MOMP and Mcl-1 upregulation. Knockdown of Mcl-1 shifted minority MOMP to complete MOMP as noted by dynamic BH3 profiling and increased apoptosis. Minority MOMP contributes to DCA induced carcinogenesis in preneoplastic BE. Mcl-1 provided a balance within the mitochondria that induced resistance complete MOMP and cell death. Targeting Mcl-1 may be a therapeutic strategy in EAC.

Topics: Apoptosis; Barrett Esophagus; Bile Acids and Salts; Carcinogenesis; Cell Line; Cell Membrane Permeability; Cytochromes c; DNA Damage; Esophageal Neoplasms; Esophagus; Gastrointestinal Agents; Humans; Mitochondria; Myeloid Cell Leukemia Sequence 1 Protein; Signal Transduction

Doxycycline (DOX) exhibits anti-inflammatory, anti-tumor, and pro-apoptotic activity and is being tested in clinical trials as a chemotherapeutic agent for several cancers, including colon cancer.. In the current study, the chemotherapeutic activity of doxycycline was tested in a rat model of colon carcinogenesis, induced by colon specific cancer promoter, 1,2, dimethylhydrazine (DMH) as well as study the effect of DOX-alone on a separate group of rats.. Doxycycline administration in DMH-treated rats (DMH-DOX) unexpectedly increased tumor multiplicity, stimulated progression of colonic tumor growth from adenomas to carcinomas and revealed metastasis in small intestine as determined by macroscopic and histopathological analysis. DOX-alone treatment showed markedly enhanced chronic inflammation and reactive hyperplasia, which was dependent upon the dose of doxycycline administered. Moreover, immunohistochemical analysis revealed evidence of inflammation and anti-apoptotic action of DOX by deregulation of various biomarkers.. These results suggest that doxycycline caused chronic inflammation in colon, small intestine injury, enhanced the efficacy of DMH in tumor progression and provided a mechanistic link between doxycycline-induced chronic inflammation and tumorigenesis. Ongoing studies thus may need to focus on the molecular mechanisms of doxycycline action, which lead to its inflammatory and tumorigenic effects.

Topics: 1,2-Dimethylhydrazine; Animals; Body Weight; Carcinogenesis; Caspase 3; Caspase 9; Cell Proliferation; Chronic Disease; Colonic Neoplasms; Cytochromes c; Down-Regulation; Doxycycline; Immunohistochemistry; Inflammation; Intestine, Small; Male; Matrix Metalloproteinase 9; Neoplasm Metastasis; NF-kappa B; Rats, Sprague-Dawley; Tumor Suppressor Protein p53; Up-Regulation; Vascular Endothelial Growth Factor A

Resistance in apoptosis by disruption in signaling pathways is a common trait in malignancy. Celecoxib, a specific COX-2 inhibitor, has been reported to exert chemopreventive effect by inducing apoptosis. However, high doses or chronic usage of celecoxib for longer periods have various side effects. n-3 PUFA rich fish oil also abrogates COX-2 expression in tumors and thereby, has chemopreventive action. Combinatorial strategy using these two has been reported to be beneficial in mammary carcinoma. The present study was designed to understand the role of intrinsic and extrinsic apoptotic pathways in chemopreventive effect of celecoxib and fish oil in the initial phases of mammary carcinogenesis.. Female Wistar rats were distributed into control and DMBA treated groups and further subdivided based on pretreatment with celecoxib and/or fish oil. The animals were subsequently maintained for 90 days and then sacrificed. The proteins involved in intrinsic and extrinsic pathways were assessed in isolated mammary epithelial cells using flowcytometry.. An increase in Bax, Bcl-2, Fas, FasL and caspase 8 levels was observed in DMBA treated animals. Celecoxib and/or fish oil further upregulate Bax, Fas, Fas L and caspase-8 while Bcl-2 levels were decreased. However maximal effect was observed with combinatorial dose of celecoxib and fish oil regimen.. Administration of a combinatorial therapy of fish oil and celecoxib in mammary carcinoma exert better chemopreventive effect by modulation of both intrinsic and extrinsic apoptotic pathways.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Apoptosis; bcl-2-Associated X Protein; Carcinogenesis; Caspase 8; Celecoxib; Cell Separation; Cytochromes c; Epithelial Cells; Fas Ligand Protein; fas Receptor; Female; Fish Oils; Mammary Neoplasms, Animal; Mammary Neoplasms, Experimental; Membrane Potential, Mitochondrial; Rats, Wistar; Signal Transduction

Celastrol, an active ingredient of Tripterygium Wilfordii, is a traditional Chinese medicinal herb, which has attracted interests for its potential anti-inflammatory and anti-cancer activities. The aim of this study was to evaluate the anti-tumor effect of Celastrol against diethylnitrosamine (DEN)-induced hepatocellular carcinoma (HCC) in rats and furthermore, to explore the underlying mechanism. Sprague-Dawley rats were intragastrically administered with DEN (10mg/kg) for 6 days every week and persisting 16 weeks. The number of nodules was calculated. Hematoxylin-Eosin (HE) staining was used to evaluate the hepatic pathological lesions. The levels of serum alanine aminotransferase (ALT), glutamic oxalacetic transaminase (AST), alkaline phosphatase (ALP) and alpha fetoprotein (AFP) were analyzed by Elisa kits, and the protein levels of p53, Murine double minute (MDM) 2, Bax, Bcl-2, Bcl-xl, cytochrome C, Caspase-3, Caspase-9 and Poly (ADP-ribose) polymerase (PARP) were analyzed by western blot. The results showed that Celastrol could significantly decrease the mortality, the number of tumor nodules and the index of liver in the Celastrol groups compared with DEN-treated group. Moreover, Celastrol obviously improved the hepatic pathological lesions and decreased the elevated levels of ALT, AST, ALP and AFP. Meanwhile, Celastrol suppressed the expression of the protein MDM2, activated the intrinsic mitochondrial apoptosis pathway induced by p53, inhibited anti-apoptotic Bcl-2 and Bcl-xl, induced the pro-apoptotic Bax, cytochrome C, PARP and caspases. These results suggested that Celastrol had a good therapeutic action in reversing DEN-induced HCC rats, which may be associated with the apoptosis of hepatoma cells induced by Celastrol.

Topics: Animals; Antineoplastic Agents; bcl-2-Associated X Protein; bcl-X Protein; Carcinogenesis; Carcinoma, Hepatocellular; Caspase 3; Caspase 9; Cytochromes c; Diethylnitrosamine; Gene Expression Regulation, Neoplastic; Liver; Liver Neoplasms; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Mitochondria; Pentacyclic Triterpenes; Poly(ADP-ribose) Polymerases; Proto-Oncogene Proteins c-mdm2; Rats; Rats, Sprague-Dawley; Triterpenes; Tumor Suppressor Protein p53

Cancer stem cells (CSCs) are shown to be responsible for initiation and progression of tumors in a variety of cancers. We previously showed that anthocyanin-containing baked purple-fleshed potato (PP) extracts (PA) suppressed early and advanced human colon cancer cell proliferation and induced apoptosis, but their effect on colon CSCs is not known. Considering the evidence of bioactive compounds, such as anthocyanins, against cancers, there is a critical need to study anticancer activity of PP, a global food crop, against colon CSCs. Thus, isolated colon CSCs (positive for CD44, CD133 and ALDH1b1 markers) with functioning p53 and shRNA-attenuated p53 were treated with PA at 5.0 μg/ml. Effects of baked PP (20% wt/wt) against colon CSCs were also tested in vivo in mice with azoxymethane-induced colon tumorigenesis. Effects of PA/PP were compared to positive control sulindac. In vitro, PA suppressed proliferation and elevated apoptosis in a p53-independent manner in colon CSCs. PA, but not sulindac, suppressed levels of Wnt pathway effector β-catenin (a critical regulator of CSC proliferation) and its downstream proteins (c-Myc and cyclin D1) and elevated Bax and cytochrome c, proteins-mediating mitochondrial apoptosis. In vivo, PP reduced the number of crypts containing cells with nuclear β-catenin (an indicator of colon CSCs) via induction of apoptosis and suppressed tumor incidence similar to that of sulindac. Combined, our data suggest that PP may contribute to reduced colon CSCs number and tumor incidence in vivo via suppression of Wnt/β-catenin signaling and elevation of mitochondria-mediated apoptosis.

Topics: Animals; Anthocyanins; Antineoplastic Agents; Apoptosis; Azoxymethane; bcl-2-Associated X Protein; beta Catenin; Carcinogenesis; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cell Transformation, Neoplastic; Colonic Neoplasms; Cytochromes c; Food; Humans; In Situ Nick-End Labeling; Lentivirus; Male; Mice; Mitochondria; Neoplastic Stem Cells; RNA, Small Interfering; Solanum tuberosum; Sulindac; Tumor Suppressor Protein p53; Wnt Proteins

Parthenolide (PT), a principal active component in medicinal plants, has been used conventionally to treat migraine and inflammation. This component has recently been reported to induce apoptosis in cancer cells, through mitochondrial dysfunction. In the present study, we investigated PT-mediated cell death signaling pathway by focusing on the involvement of Bcl-2 family members in human colorectal cancer cells. We also investigated the inhibitory effect of PT on tumor growth in xenografts. Using the human colorectal cancer cell lines HT-29, SW620 and LS174T, we demonstrated that treatment of these cancer cells with PT induces apoptosis using MTT, Annexin V assay and Hoechst 33258 staining. Apoptosis through the mitochondrial pathway was confirmed by detecting regulation of Bcl-2 family members, cytochrome c release and caspase activation. Moreover, intraperitoneal injection of PT showed significant inhibition of tumor growth, angiogenesis in the xenograft model. These results demonstrate that PT exhibits anti-cancer activity in human colorectal cancer in vitro and in vivo. These findings may also provide a novel approach for the treatment of colorectal cancer.

Topics: Apoptosis; Carcinogenesis; Colorectal Neoplasms; Cytochromes c; Genes, bcl-2; HT29 Cells; Humans; Mitochondria; Neovascularization, Pathologic; Sesquiterpenes; Signal Transduction; Xenograft Model Antitumor Assays

Topics: Animals; Carcinogenesis; Cytochromes c; Epidermis; Methylcholanthrene; Mice