Abstract
Resistance to cisplatin (CDDP) is a major cause of cancer treatment failure, including human breast cancer. The tumor suppressor protein p53 is a key factor in the induction of cell cycle arrest, DNA repair, and apoptosis in response to cellular stimuli. This protein is phosphorylated in serine 15 and serine 20 during DNA damage repair or in serine 46 to induce apoptosis. Resveratrol (Resv) is a natural compound representing a promising chemosensitizer for cancer treatment that has been shown to sensitize tumor cells through upregulation and phosphorylation of p53 and inhibition of RAD51. We developed a CDDP-resistant MCF-7 cell line variant (MCF-7R) to investigate the effect of Resv in vitro in combination with CDDP over the role of p53 in overcoming CDDP resistance in MCF-7R cells. We have shown that Resv induces sensitivity to CDDP in MCF-7 and MCF-7R cells and that the downregulation of p53 protein expression and inhibition of p53 protein activity enhances resistance to CDDP in both cell lines. On the other hand, we found that Resv induces serine 20 (S20) phosphorylation in chemoresistant cells to activate p53 target genes such as PUMA and BAX, restoring apoptosis. It also changed the ratio between BCL-2 and BAX, where BCL-2 protein expression was decreased and at the same time BAX protein was increased. Interestingly, Resv attenuates CDDP-induced p53 phosphorylation in serine 15 (S15) and serine 46 (S46) probably through dephosphorylation and deactivation of ATM. It also activates different kinases, such as CK1, CHK2, and AMPK to induce phosphorylation of p53 in S20, suggesting a novel mechanism of p53 activation and chemosensitization to CDDP.
Highlights
Cisplatin (CDDP) is an anticancer drug for the treatment of various types of cancer including human breast cancer
R); both cells were treated with different CDDP concentrations
IC50 by of CDDP was decreased by Resv in both cell lines; in MCF-7 cells the IC50 for R
Summary
Cisplatin (CDDP) is an anticancer drug for the treatment of various types of cancer including human breast cancer. Resistance to CDDP is a major cause of treatment failure, and the molecular mechanisms are poorly understood [1] Due to this phenomenon, it is necessary to continue the search for effective chemosensitizers for cancer treatment. Resv can sensitize resistant cells to chemotherapeutic agents, including CDDP, by overcoming one or more mechanisms of chemoresistance [6,7]. We previously reported that treatment of MCF-7 cells with Resv induces the downregulation of several genes related to mismatch repair, DNA replication, and homologous recombination, decreasing protein levels of the MRN complex (MRE11-NBS1-RAD50) which is part of the homologous recombination DNA repair pathway [22]. It is of maximal importance to understand the molecular mechanisms by which Resv overcome chemoresistance in cancer cells, alone or in combination with chemotherapeutic agents (e.g., CDDP), to enhance treatment efficacy and reduce toxicity. CDDP in MCF-7 and MCF-7R cells, the role of p53 in CDDP resistance, the involvement of Resv in p53 phosphorylation, and the role of the p53 pathway for overcoming resistance in MCF-7R cells
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
