TRAIL sensitize MDR cells to MDR-related drugs by down-regulation of P-glycoprotein through inhibition of DNA-PKcs/Akt/GSK-3β pathway and activation of caspases

Abstract

BackgroundThe development of new modulator possessing high efficacy, low toxicity and high selectivity is a pivotal approach to overcome P-glycoprotein (P-gp) mediated multidrug resistance (MDR) in cancer treatment. In this study, we suggest a new molecular mechanism that TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) down-regulates P-glycoprotein (P-gp) through inhibition of DNA-PKcs/Akt/GSK-3β pathway and activation of caspases and thereby sensitize MDR cells to MDR-related drugs.ResultsMDR variants, CEM/VLB10-2, CEM/VLB55-8 and CEM/VLB100 cells, with gradually increased levels of P-gp derived from human lymphoblastic leukemia CEM cells, were gradually more susceptible to TRAIL-induced apoptosis and cytotoxicity than parental CEM cells. The P-gp level of MDR variants was positively correlated with the levels of DNA-PKcs, pAkt, pGSK-3β and c-Myc as well as DR5 and negatively correlated with the level of c-FLIPs. Hypersensitivity of CEM/VLB100 cells to TRAIL was accompanied by the activation of mitochondrial apoptotic pathway as well as the activation of initiator caspases. In addition, TRAIL-induced down-regulation of DNA-PKcs/Akt/GSK-3β pathway and c-FLIP and up-regulation of cell surface expression of death receptors were associated with the increased susceptibility to TRAIL of MDR cells. Moreover, TRAIL inhibited P-gp efflux function via caspase-3-dependent degradation of P-gp as well as DNA-PKcs and subsequently sensitized MDR cells to MDR-related drugs such as vinblastine and doxorubicin. We also found that suppression of DNA-PKcs by siRNA enhanced the susceptibility of MDR cells to vincristine as well as TRAIL via down-regulation of c-FLIP and P-gp expression and up-regulation of DR5.ConclusionThis study showed for the first time that the MDR variant of CEM cells was hypersensitive to TRAIL due to up-regulation of DR5 and concomitant down-regulation of c-FLIP, and degradation of P-gp and DNA-PKcs by activation of caspase-3 might be important determinants of TRAIL-induced sensitization of MDR cells to MDR-related drugs. Therefore, combination of TRAIL and chemotherapeutic drugs may be a good strategy for treatment of cancer with multidrug resistance.

Breast cancer: Small molecules targeting apoptosis, a prospective approach to safe scientific success

“…In another study, apigenin induced extrinsic apoptosis pathway, up-regulating the levels of cleaved caspase-8, and inducing the cleavage of poly (ADP-ribose) polymerase. However, apigenin did not induce apoptosis via intrinsic mitochondrial apoptosis pathway since this compound did not decrease mitochondrial membrane potential maintaining red fluorescence and did not affect the levels of B-cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein [31]. Moreover, apigenin reduced the tyrosine phosphorylation of HER2 (phospho-HER2 level) in MCF-7 HER2 cells, and up-regulated the levels of p53, phospho-p53 and p21 in MCF-7 vec and MCF-7 HER2 cells [31].…”

“…However, apigenin did not induce apoptosis via intrinsic mitochondrial apoptosis pathway since this compound did not decrease mitochondrial membrane potential maintaining red fluorescence and did not affect the levels of B-cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein [31]. Moreover, apigenin reduced the tyrosine phosphorylation of HER2 (phospho-HER2 level) in MCF-7 HER2 cells, and up-regulated the levels of p53, phospho-p53 and p21 in MCF-7 vec and MCF-7 HER2 cells [31]. TRAIL receptor activating agents have been found to exhibit favourable in vitro and in vivo activity in treatment of several malignancies, including breast and gynaecological cancers.…”

Acquisition of MDR phenotype by leukemic cells is associated with increased caspase‐3 activity and a collateral sensitivity to cold stress

“…6c) over basal protein levels (cells incubated at 378C). This result shows that under cold stress, these cells up-regulate P-gp expression, probably as part of a general response to any kind of stress [Seo et al, 2010].…”

“…P-gp efflux activity has been described to be strongly affected by temperature, functioning optimally at 378C but becoming inactive at 48C [Seo et al, 2010]. To test this in our model, the accumulation of the P-gp substrate, rhodamine 123 [Legrand et al, 2001] was analyzed in L1210, L1210R, and CBMC-6 cells incubated at both 378C and 48C for different times.…”

Glycogen synthase kinase 3β inhibitor (2′Z,3′E)-6-bromo-indirubin-3′-oxime enhances drug resistance to 5-fluorouracil chemotherapy in colon cancer cells

“…Some genes may be the potential multifunction drug resistance targets, which join  two or more metabolic and signal transduction pathways [3] . Glycogen synthase kinase 3β (GSK-3β), as a multifunctional kinase, participates in the regulation of cell proliferation, apoptosis and drug resistance in tumor cells by influencing the downstream factors, and has become an attractive target for tumor therapy [4][5][6][7] . However, the role of GSK-3β in the drug resistance and biological properties of tumor cells remains controversial.…”