Caspase 3 in breast cancer.
ABSTRACT An inability to undergo apoptosis is widely thought to contribute to both tumorigenesis and tumor progression. One of the key mediators of apoptosis is the thiol protease caspase 3. In this investigation, caspase 3 mRNA and protein expression in breast cancer was examined.
Caspase 3 was measured at the mRNA level using reverse transcription-PCR and at the protein level using both Western blotting and activity assays. Levels of apoptosis were determined using an ELISA, which detects nucleosomes released during DNA fragmentation.
Relative levels of caspase 3 mRNA were similar in breast carcinomas (n = 103), fibroadenomas (n = 25), and normal breast tissues (n = 6). However, levels of both the precursor and active forms of caspase 3 were significantly higher in carcinomas compared with both fibroadenomas (P = 0.0188) and normal breast tissues (P = 0.0002). Levels of apoptosis were also highest in the carcinomas and correlated significantly with active caspase 3 levels (r = 0.481; P = 0.0003). In the carcinomas, expression of caspase 3 showed no significant relationship with either tumor size, tumor grade, nodal status, or steroid receptor status but was significantly higher in ductal carcinomas than in lobular carcinomas (P = 0.0188).
We conclude that rates of apoptosis as measured by both caspase 3 activation and nucleosome release are higher in breast cancer than in nonmalignant breast tissue. This finding would appear to conflict with the widely held belief that apoptosis is reduced in malignancy. The proliferation:apoptosis ratio, however, may be higher in carcinomas than in the corresponding normal tissue.
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ABSTRACT: The evasion of apoptosis is a key characteristic of cancer, and thus strategies to selectively induce apoptosis in cancer cells hold considerable promise in personalized anticancer therapy. Structurally similar procaspase activating compounds PAC-1 and S-PAC-1 restore procaspase-3 activity through the chelation of inhibitory zinc ions in vitro, induce apoptotic death of cancer cells in culture, and reduce tumor burden in vivo. Ip or iv administrations of high doses of PAC-1 are transiently neurotoxic in vivo, while S-PAC-1 is safe even at very high doses and has been evaluated in a phase I clinical trial of pet dogs with spontaneously occurring lymphoma. Here we show that PAC-1 and S-PAC-1 have similar mechanisms of cell death induction at low concentrations (less than 50 μM), but at high concentrations PAC-1 displays unique cell death induction features. Cells treated with a high concentration of PAC-1 have a distinctive gene expression profile, unusual cellular and mitochondrial morphology, and an altered intracellular Ca(2+) concentration, indicative of endoplasmic reticulum (ER) stress-induced apoptosis. These studies suggest strategies for anticancer clinical development, specifically bolus dosing for PAC-1 and continuous rate infusion for S-PAC-1.Molecular Pharmaceutics 04/2012; 9(5):1425-34. · 4.57 Impact Factor
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ABSTRACT: Increasing ability of early breast cancer (BC) diagnosis leading to more early stage detection, better survival, and low relapse marks one of the milestones achieved over the decades. Foregoing poses a challenge for clinicians regarding optimal treatment, in which over- and under-treatment should be avoided. Classical prognostic and predictive factors fall short for individualized adjuvant therapy selection in this patient group. The key to better characterization may be found in the biology underlying individual tumors. We hypothesized that markers related to cellular proliferation and apoptosis and the balance between these two processes in tumor development will be predictive for clinical outcome. Our study population (N = 822) consisted of all early stage BC patients primarily treated with surgery in our center between 1985 and 1996. Sections of available tumor tissue (87 %, 714/822) were immunohistochemically stained for expression of p53, active-caspase-3, and Ki67. In 43 % (304/714) and 18 % (126/714) of this cohort, respectively, a biochemical C2P(®) risk prediction and caspase-3 assay were performed. Expression data of the mentioned markers, single, or combined, were analyzed. Results showed that both the single and combined markers, whether of apoptotic or proliferative origin had associations with clinical outcome. An additive effect was seen for the hazard ratios when data on p53, active caspase-3, and Ki67 status were combined. The assembled prognostic apoptotic-proliferative subtype showed significant association for both the overall survival (p = 0.024) and relapse-free period (p = 0.001) in the multivariate analyses of grade I breast tumors. Combined markers of tumor cell apoptosis and proliferation represent tumor aggressiveness. The apoptotic-proliferative subtypes that we present in this study represent a clinical prognostic profile with solid underlying biological rationale and pose a promising method for accurate identification of grade I BC patients in need of an aggressive therapeutic approach, thus contributing to precision medicine in BC disease.Breast Cancer Research and Treatment 11/2013; · 4.47 Impact Factor
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ABSTRACT: The current study deals with the molecular mechanism of radiation-induced cell death (RICD) in Escherichia coli. Irradiated E. coli cells displayed markers similar to those found in eukaryotic programmed cell death (PCD) such as caspase-3 activation and phosphatidylserine externalization. RICD was found to be suppressed upon pretreatment with sublethal concentrations of rifampicin or chloramphenicol, indicating the requirement of de novo gene expression. RICD was also found to be inhibited by cell permeable inhibitors of caspase-3 or poly (ADP-ribose) polymerase, indicating the involvement of PCD during RICD in E. coli. Radiation-induced SOS response was alleviated as observed with decrease in LexA level and also reduced cell filamentation frequency in the presence of caspase inhibitor. Further, the inhibitor-mediated rescue was not observed in single-gene knockouts of umuC, umuD, recB and ruvA, the genes which are associated with SOS response. This implies a linkage between SOS response and PCD in radiation-exposed E. coli cells.Archives of Microbiology 06/2013; · 1.91 Impact Factor