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Showing 2 results for Bax

Mohammad A. Pahlavani, Danial A. Vargas,
Volume 5, Issue 1 (1-2001)
Abstract

We have previously shown that the proliferative response of T cells to antigenic or mitogenic stimulus decreased with age and that caloric resection (CR) attenuated the age-related decline in proliferation and IL-2 expression. Because activation-induced apoptosis is known to regulate cell proliferation and eliminate the high number of activated cells during an immune response, it was of interest to determine what effect aging or CR has on activation-induced apoptosis in T cells. Splenic T cells isolated from young (6-month) and old (25-month) mice fed ad libitum (control group) and from old (24-month) mice fed a restricted diet (40% caloric restriction) that began at 6 weeks of age. T cells were stimulated with superantigen staphylococcal enterotoxin B (SEB) or anti-CD3 antibody (primary stimulus) for 72 to 96 h, followed by restimulation with anti-CD3 (secondary stimulus). Activation-induced apoptosis was assessed by DNA fragmentation assay and the expression Fas/CD95 and Fas-ligand (Fas-L) was measured by flow cytometry. We found that the amount of DNA fragmentation was significantly (p<0.05) increased in the stimulated and restimulated T cells from old control mice and old caloric restricted mice compared to young control mice. The increase in DNA fragmentation with age was paralleled with an increase in the proportion of the cells expressing Fas and Fas-L. However, CR had no significant effect on the age-related increase in DNA fragmentation, Fas, or Fas-L expression. We also measured the Bcl-2 and Bax protein level and found that the level of Bcl-2 decreased and Bax increased with age and that CR had no effect on the age-related changes in the level of Bcl-2 or Bax protein. These results demonstrate that aging but not CR alters activation-induced apoptosis in mice T cells.
Ehsan Khodapasand, Narges Jafarzadeh, Farid Farrokhi, Behnam Kamalidehghan, Massoud Houshmand,
Volume 19, Issue 2 (4-2015)
Abstract

Background: Bax and Bcl-2 are the major members of Bcl-2 family whose play a key role in tumor progression or inhibition of intrinsic apoptotic pathway triggered by mitochondrial dysfunction. Therefore, the balance between pro- and anti-apoptotic members of this family can determine the cellular fate. Methods: In this study, the relative level of mRNA expression of Bax and Bcl-2 genes was determined using RNA extraction, cDNA synthesis and RT-qPCR technique from 22 tumoral tissues and adjacent non-tumoral tissues from adenocarcinoma colorectal cancer. Results: The potential prognostic and predictive significance of Bax and Bcl-2 gene expression and Bax/Bcl-2 ratio were demonstrated in colorectal cancer. The significant correlation between qPCR data and different clinicopathologic parameters of colorectal carcinoma, including age, gender, tumor size, tumor stage, tumor location, and tumor differentiation was also examined. Interestingly, no significant correlation was seen between Bax and Bcl-2 expressions and clinicopathological parameters of colorectal cancer. However, Bax/Bcl-2 ratio was statistically correlated with age and tumor location. Patients with age above 50 showed decreased levels of Bax/Bcl-2 ratio. Moreover, the Bax/Bcl-2 ratio was significantly lower in tumors resected from colon compared to sigmoid colon, rectosigmoid and rectum tumors. Conclusion: This study indicates a significant correlation between age and tumor location with Bax/Bcl-2 expression ratio, suggesting predictive value as a potential molecular marker of colorectal cancer.

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