Insight into the role of PIKK family members and NF-кB in DNAdamage-induced senescence and senescence-associated secretory phenotype of colon cancer cells

Abstract

Senescence of cancer cells is an important outcome of treatment of many cancer types. Cell senescence is a permanent cell cycle arrest induced by stress conditions, including DNA damage. DNA damage activates DNA damage response (DDR), which involves members of the phosphatidylinositol 3-kinase-related kinase (PIKK) superfamily: protein kinases ATM, ATR, and DNA-PKcs. The so-far collected data indicate that ATM, with its downstream targets CHK2, p53, and p21, is the key protein involved in DDR-dependent senescence. It was also documented that the so-called senescence-associated secretory phenotype-SASP relies on ATM/CHK2, and not on p53 signaling. Moreover, genotoxic agents used in cancer treatment can activate NF-κB, which also induces transcription of SASP genes. In this paper, we have studied the involvement of three PIKK family members in colon cancer cell senescence and connection between DNA-damage-induced senescence and NF-κB-regulated SASP in p53-proficient and p53-deficient colon cancer cells treated with doxorubicin. We showed that doxorubicin induced cell senescence in both p53+/+ and p53−/− HCT116 cells, proving that this process is p53-independent. Senescence was successfully abrogated by a PIKK inhibitor, caffeine, or by simultaneous silencing of three PIKKs by specific siRNAs. By silencing individual members of PIKK family and analyzing common markers of senescence, the level of p21 and SA-β-Gal activity, we came to the conclusion that ATR kinase is crucial for the onset of senescence as, in contrast to ATM and DNA-PKsc, it could not be fully substituted by other PIKKs. Moreover, we showed that in case of silencing the three PIKKs, there was no SASP reduction accompanying the decrease in the level of p21 and SA-β-Gal (Senescence-Associated-β-Galactosidase) activity; whereas knocking down the NF-κB component, p65, abrogated SASP, but did not affect other markers of senescence, proving that DNA damage regulated senescence independently and NF-κB evoked SASP.

RETRACTED ARTICLE: Reversible inhibitor of CRM1 sensitizes glioblastoma cells to radiation by blocking the NF-κB signaling pathway

“…In recent years, clinical evidence has shown that postoperative tumors are insensitive to radiotherapies and chemotherapies, which is associated with increased NF-κΒ activity [19,32]. Anticancer radiotherapies generally eliminate tumor cells by damaging DNA, inducing apoptosis, and blocking tumor cell proliferation.…”

“…NF-κΒ is also known to prevent apoptosis through its involvement in cell cycle arrest and DNA repair, and plays an important role in tumor proliferation and apoptosis [16,17]. In many types of tumors, structural activation of NF-κΒ is involved in tumor resistance to chemotherapy and radiotherapy [18,19]. NF-κΒ and NF-κΒ-regulated gene products, including Bcl-xl, cyclin D1, matrix metalloproteinase-9 (MMP-9), vascular endothelial growth factor (VEGF), and cyclooxygenase-2 (COX-2), are involved in tumor cell resistance to radiotherapy [20,21].…”

Thymoquinone and Costunolide Induce Extensive Apoptosis of Senescent Colon and Senescent Breast Cancer Cells

“…The same results were found when HCT116 or MCF7 cell lines were treated with 100 nM of Dox [2,27,28]. HCT116 exposed to 50 nM [29][30][31], 75 nM [32], 100 nM [2,31,[33][34][35][36], and 200 nM [37] for 1-4 days exhibited the features of senescence. Higher doses of Dox induced senescence in HCT116 by doses of 1 µM for 2 h [38] and 500 nM for 4 h [39].…”

Czym jest i czym nie jest starzenie komórki?

“…It seems however, that DNA damage can evoke cell senescence even when DDR is not fully activated due to mutations in genes encoding the effector proteins that may occur in cancer and non-cancer cells. In fact, we documented this for HCT116 p53-deficient cancer cells [Mosieniak et al, 2012;Strzeszewska et al, 2018] and for an immortal line of lymphocytes derived from a patient with Nijmegen Breakage Syndrome (NBS) caused by mutation in the nibrin gene [Alster et al, 2014]. In normal VSMCs undergoing curcumin-induced senescence we showed activation of ATM but, unexpectedly, ATM silencing had no effect on cell senescence [Grabowska et al, 2015].…”

“…This implies that even if activated, ATM is not the crucial for transducing the signal for cell senescing. Indeed, our recent results led us to the conclusion that ATR, but not ATM kinase, is crucial for the onset of senescence in HCT 116 cells [Strzeszewska et al, 2018]. However, ATR does not play important role in curcumin-induced senescence of VSMCs (submitted), which indicates cell senescence diversity.…”