Glutamine metabolism targeting liposomes for synergistic chemosensitization and starvation therapy in ovarian cancer.

Platinum-based chemotherapy is a first-line therapeutic regimen against ovarian cancer (OC); however, the therapeutic potential is always reduced by glutamine metabolism. Herein, a valid strategy of inhibiting glutamine metabolism was proposed to cause tumor starvation and chemosensitization. Specifically, reactive oxygen species-responsive liposomes were developed to co-deliver cisplatin (CDDP) and bis-2-(5-phenylacetamido-1,3,4-thiadiazol-2-yl) ethyl sulfide (BPTES) [C@B LPs]. The C@B LPs induced effective tumor cell starvation and significantly sensitized OC cells to CDDP by reducing glutathione generation to prevent CDDP detoxification, suppressing ATP production to avoid CDDP efflux, hindering nucleotide synthesis to aggravate DNA damage induced by CDDP, and blocking mammalian target of rapamycin (mTOR) signaling to promote cell apoptosis. More importantly, C@B LPs remarkably inhibited tumor growth in vivo and reduced the side effects. Taken together, this study provided a successful strategy of synergistic chemosensitization and starvation therapy escalating the rate of therapeutic success in OCs. STATEMENT OF SIGNIFICANCE: This work proposed a valid strategy of inhibiting glutamine metabolism to cause tumor starvation and chemosensitization. Specifically, ROS-responsive liposomes were developed to co-deliver cisplatin CDDP and BPTES [C@B LPs]. The C@B LPs induced effective tumor cell starvation and significantly sensitized OC cells to cisplatin by reducing glutathione generation to prevent cisplatin detoxification, suppressing ATP production to avoid cisplatin efflux, hindering nucleotide synthesis to aggravate DNA damage induced by cisplatin, and blocking mTOR signaling to promote cell apoptosis. More importantly, C@B LPs remarkably inhibited tumor growth in vivo and reduced the side effects. Taken together, this study provided a successful strategy of synergistic chemosensitization and starvation therapy escalating the rate of therapeutic success in OCs.

BNIP3 contributes to cisplatin-induced apoptosis in ovarian cancer cells.

BNIP3 is a proapoptotic protein that mediates apoptosis, necrosis and autophagy. However, the involvement of BNIP3 in cisplatin-induced apoptosis in ovarian cancer is not clear. In this study, we examined the role of BNIP3 in ovarian cancer during cisplatin treatment and its correlation with clinical outcomes. We first measured cisplatin cytotoxicity and BNIP3 levels before and after cisplatin exposure for ovarian cancer cell lines A2780, SKOV3, OVCAR4, OV2008, ES2 and HO8910. BNIP3 was observed to be differentially expressed in these cell lines, and cisplatin induced a significant increase in BNIP3 levels in A2780 and OVCAR4. BNIP3 knockdown with siRNA in A2780 and OVCAR4 significantly reduced cisplatin cytotoxicity in these two cell lines and alleviated cisplatin-induced apoptosis. We searched the online databases Gene Expression Omnibus and The Cancer Genome Atlas to analyze the correlation between BNIP3 level and overall survival and progression-free survival in patients with ovarian cancer. Pooled analyses showed that higher BNIP3 level was correlated with poorer overall survival (95% confidence intervals; hazard ratio = 1.18, 1.04-1.34; P = 0.013) and progression-free survival (95% confidence intervals; hazard ratio = 1.26, 1.10-1.43; P = 0.00049). However, the results of individual datasets and stratification analyses of histology, FIGO (Federation Internationale de Gynecolgie et d'Obstetrique) stage, chemotherapy regimen and P53 mutation status varied. These findings indicate that cisplatin-induced apoptosis is dependent on BNIP3 level in ovarian cancer cell lines. Targeting BNIP3 may therefore be a potential way of restoring cisplatin sensitivity.

Toosendanin mediates cisplatin sensitization through targeting Annexin A4/ATP7A in non-small cell lung cancer cells.

Cisplatin (CDDP) is used in the treatment of non-small cell lung cancer (NSCLC), but due to the development of resistance, the benefit has been limited. Toosendanin (TSN) has shown therapeutic effects on NSCLC; however, the role of TSN on CDDP sensitization in NSCLC remains unknown. The antitumor effects of TSN and CDDP sensitization mediated by TSN were explored. TSN was added in various amounts to measure dose- and time-dependent cytotoxicity. Intracellular CDDP was detected by high-performance liquid chromatography. The protein levels of ATP7A, ATP7B, hCTR1, MRP-2, P-gp and Annexin A4 (Anxa4) were analyzed. The tests were conducted using normal NSCLC (A549 cell line) and CDDP-resistant cells (A549/DDP cell line). Anxa4 promotes CDDP resistance by regulating ATP7A, so Anxa4 was overexpressed and silenced and also transfected with pcMV6 or siRNA/ATP7A, respectively. Mechanistic investigations revealed that TSN decreased relative viability in NSCLC cells. Remarkably, TSN significantly enhanced CDDPsensitization in invalid doses. TSN downregulated Anxa4 expression, enhanced intracellular CDDP, and had no effect on MRP-2, P-gp, ATP7A, ATP7B or hCTR1. Subsequently, overexpression of Anxa4 led to a significant decrease in intracellular CDDP concentration. The adjustment of CDDP concentration regulated by TSN disappeared in Anxa4 or ATP7A-silenced cells. TSN also enhanced CDDP sensitization in single ATP7A-overexpressing cells, but had no effect on cells with simultaneous ATP7A overexpression and Anxa4 silencing. The present study suggests that TSN can mediate CDDP sensitization in NSCLC through downregulation of Anxa4.

Study on the cisplatin-sensitization effect of tripterygium glycosides on cisplatin-resistant human epithelial ovarian cancer cells (SKOV3/DDP) in vitro / 中国临床药理学与治疗学

AIM:To study the cisplatin-sensitization effect and mechanism of tripterygium glycosides on cisplatin-resistant human epithelial ovarian cancer cells (SKOV3/DDP).METHODS:The SKOV3/DDP cells in exponential phase of growth were randomly divided into eight groups:blank control group,10 μg/mL DDP group,50 μg/mL GTW group,800 μg/mL GTW group,3 200 μg/mL GTW group,10 μg/mL DDP + 50 μg/mL GTW group,10 μg/mL DDP + 800 μg/mL GTW group and 10 μg/mL DDP + 3 200 μg/mL GTW group.Cell counting kit 8 and flow cytometry and western blot were used to detect the growth inhibiting rate and apoptosis rate and relative expression of GST-π,MDR1,STAT3,p-STAT3 of SKOV3/DDP cells of every group.RESULTS:DDP and GTW produce an additive effect when used concurrently in inhibiting growth of SKOV3/DDP cells.800 μg/mL GTW or 3 200 μg/mL GTW combined with 10 μg/mL DDP can significantly induce apoptosis of SKOV3/DDP cells and downregulate the expression of p-STAT3 (P ＜ 0.05).CONCLUSION:GTW can significantly enhance sensitivity of SKOV3/DDP cells to DDP.The underlying mechanism may be related with down-regulating the expression of p-STAT3 in STAT3 pathway.

Anticancer properties and enhancement of therapeutic potential of cisplatin by leaf extract of Zanthoxylum armatum DC

BACKGROUND: Clinical use of chemotherapeutic drug, cisplatin is limited by its toxicity and drug resistance. Therefore, efforts continue for the discovery of novel combination therapies with cisplatin, to increase efficacy and reduce its toxicity. Here, we screened 16 medicinal plant extracts from Northeast part of India and found that leaf extract of Zanthoxylum armatum DC. (ZALE) induced cytotoxicity as well as an effect on the increasing of the efficiency of chemotherapeutic drugs (cisplatin, mitomycin C and camptothecin). This work shows detail molecular mechanism of anti-cancer activity of ZALE and its potential for combined treatment regimens to enhance the apoptotic response of chemotherapeutic drugs. RESULTS: ZALE induced cytotoxicity, nuclear blebbing and DNA fragmentation in HeLA cells suggesting apoptosis induction in human cervical cell line. However, the apoptosis induced was independent of caspase 3 activation and poly ADP ribose polymerase (PARP) cleavage. Further, ZALE activated Mitogen-activated protein kinases (MAPK) pathway as revealed by increased phosphorylation of extracellular-signal-regulated kinases (ERK), p38 and c-Jun N-ter-minal kinase (JNK). Inhibition of ERK activation but not p38 or JNK completely blocked the ZALE induced apoptosis suggesting an ERK dependent apoptosis. Moreover, ZALE generated DNA double strand breaks as suggested by the induction γH2AX foci formation. Interestingly, pretreatment of certain cancer cell lines with ZALE, sensitized the cancer cells to cisplatin and other chemotherapeutic drugs. Enhanced caspase activation was observed in the synergistic interaction among chemotherapeutic drugs and ZALE. CONCLUSION: Purification and identification of the bio-active molecules from the ZALE or as a complementary treatment for a sequential treatment of ZALE with chemotherapeutic drugs might be a new challenger to open a new therapeutic window for the novel anti-cancer treatment.