Cisplatin Cytotoxicity Research Articles

Hybrid micelles based on Pt (IV) polymeric prodrug and TPGS for the enhanced cytotoxicity in drug-resistant lung cancer cells

Multidrug resistance (MDR) is a primary cause of failure in oncotherapy and interest is growing in the design of multi-stimuli responsive nano-carriers to synergistically deliver chemotherapeutic agents and P-gp inhibitors to reverse MDR. The hybrid micelles based on a Platinum (IV)-coordinate polymeric prodrugs and TPGS were developed to improve chemotherapy and reduce side effects. The pH/redox dual-sensitive polymers were synthesized by condensation polymerization using ortho ester monomer and diamminedichlorodisuccinatoplatinum (DSP). The hybrid micelles possessed uniform size (38 nm) and displayed good stability in various physiological conditions. In contrast, in vitro drug release profiles indicated that these micelles could be completely depolymerized under acidic and reducing environment, thereby more than 80 % cisplatin were released within 12 h at pH 5.0 plus 10 mM DTT. More importantly, a large amount of TPGS released simultaneously could effectively inhibit the function of drug efflux pumps, which significantly enhanced the cytotoxicity of cisplatin against A549/DDP cells. The growth inhibition rate of micelles on A549/DDP multicellular spheroids was 79.5 %, while that of free cisplatin was only 6.8 %. Therefore, these hybrid micelles are promising in overcoming tumor MDR and worth doing further research in vivo and extend to other therapeutic agents.

Abstract A61: FAK activity sustains intrinsic and acquired ovarian cancer resistance to platinum chemotherapy

Abstract Gene copy number alterations, tumor cell stemness, and development of platinum chemotherapy resistance contribute to high-grade serous ovarian cancer (HGSOC) recurrence. Stemness phenotypes involving Wnt-beta-catenin, aldehyde dehydrogenase activities, intrinsic platinum resistance, and tumorsphere formation are here associated with spontaneous genetic gains in KRAS, MYC, and FAK (KMF) genes, in a new aggressive murine model of ovarian cancer. Noncanonical signaling via FAK sustained KMF and human tumorsphere proliferation as well as resistance to cisplatin cytotoxicity. Platinum-resistant tumorspheres can acquire a dependence on FAK for growth. Accordingly, increased FAK tyrosine phosphorylation was observed within HGSOC patient tumors surviving neoadjuvant chemotherapy. Combining a FAK inhibitor with platinum overcame chemoresistance, triggering tumor cell apoptosis. FAK transcriptomic analyses across knockout and reconstituted cells identified 135 genes elevated by a FAK activity-dependent, beta-catenin, and Myc signaling axis including pluripotency and DNA repair genes. Identified target increases in HGSOC tumors may reflect oncogenic FAK signaling. Citation Format: Carlos J. Díaz Osterman, Duygu Ozmadenci, Elizabeth G. Kleinschmidt, Kristin N. Taylor, Allison M. Barrie, Shulin Jiang, Lisa M. Bean, Florian J. Sulzmaier, Jian Li, Xiao Lei Chen, Guo Fu, Marjaana Ojalill, Pekka Rappu, Jyrki Heino, Adam A. Mark, Guorong Xu, Kathleen M. Fisch, David T. Weaver, Jonathan A. Pachter, Balázs Győrffy, Michael T. McHale, Denise C. Connolly, Alfredo Molinolo, Dwayne G. Stupack, David D. Schlaepfer. FAK activity sustains intrinsic and acquired ovarian cancer resistance to platinum chemotherapy [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr A61.

Buformin suppresses osteosarcoma via targeting AMPK signaling pathway.

BackgroundBuformin has been reported to be a powerful anticancer drug by activating the AMPK signal. Herein, we aimed to investigate the effects of buformin on osteosarcoma.Material and methodsCellular proliferative abilities were determined by cell counting kit-8 and colony formation assays. Cellular invasion was investigated using a transwell system. Cell cycle was examined by flow cytometry. Western blot was performed to measure the expression of key proteins. Synergistic effects of buformin and cisplatin were validated in seven fresh osteosarcoma tissues.ResultsBuformin suppressed the growth of U-2 OS cells in a dose-dependent manner (IC50 = 69.1 µM). Moreover, buformin induced cell cycle arrest (P < 0.001) and impaired cellular invasion (P = 0.038). Phosphorylation of AMPK was upregulated by buformin, while phosphorylation of S6, cyclin D1, and MMP9 were significantly downregulated. In addition, buformin notably induced accumulation of reactive oxygen species and lactate and eventually decreased ATP production. In both U-2 OS cells and the primary cultured osteosarcoma tissues, buformin increased tumor sensitivity to cisplatin.ConclusionsBuformin could suppress tumor growth and invasion of osteosarcoma through directly targeting the AMPK signaling pathway. Moreover, buformin inhibited the abnormal metabolism and notably increased the cytotoxicity of cisplatin, and therefore represents a new potential treatment option for osteosarcoma.

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.

Nitric oxide affects cisplatin cytotoxicity oppositely in A2780 and A2780-CDDP cells via the connexin32/gap junction.

Chemoresistance is a main obstacle in ovarian cancer therapy and new treatment strategies and further information regarding the mechanism of the medication cisplatin are urgently needed. Nitric oxide has a critical role in modulating the activity of chemotherapeutic drugs. Our previous work showed that connexin32 contributed to cisplatin resistance. However, whether nitric oxide is involved in connexin32‐mediated cisplatin resistance remains unknown. In this study, using A2780 and A2780 cisplatin‐resistant cells, we found that S‐nitroso‐N‐acetyl‐penicillamine, a nitric oxide donor, attenuated cisplatin toxicity by decreasing gap junctions in A2780 cells. Enhancement of gap junctions using retinoic acid reversed the effects of S‐nitroso‐N‐acetyl‐penicillamine on cisplatin toxicity. In A2780 cisplatin‐resistant cells, however, S‐nitroso‐N‐acetyl‐penicillamine enhanced cisplatin toxicity by decreasing connexin32 expression. Downregulation of connexin32 expression by small interfering RNA exacerbated the effects of S‐nitroso‐N‐acetyl‐penicillamine on cisplatin cytotoxicity and upregulation of connexin32 expression by pcDNA transfection reversed the effects of S‐nitroso‐N‐acetyl‐penicillamine on cisplatin cytotoxicity. Our study suggests for the first time that combining cisplatin with nitric oxide in clinical therapies for ovarian cancer should be avoided before cisplatin resistance emerges. The present study provides a productive area of further study for increasing the efficacy of cisplatin by combining cisplatin with the specific inhibitors or enhancers of nitric oxide in clinical treatment.

Tocilizumab potentiates cisplatin cytotoxicity and targets cancer stem cells in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is a very aggressive subtype with high recurrence rate and no molecular targets for therapies. This subtype is characterized by high expression/secretion of the proinvasive/metastatic interleukin-6 (IL-6) cytokine. In the present study, we have shown that tocilizumab inhibits the IL-6/STAT3 signaling and suppresses the cancer/inflammatory epigenetic IL-6/STAT3/NF-κB positive feedback loop. Furthermore, tocilizumab inhibited the proliferative and the migratory/invasiveness capacities as well as the epithelial-to-mesenchymal transition (EMT) process in TNBC cells. Importantly, tocilizumab suppressed the stemness-related characteristics of TNBC cells, through the inhibition of the Wnt/β-catenin breast cancer stem cell-related pathway. Additionally, we have shown that tocilizumab suppresses the paracrine activation of normal breast stromal fibroblasts to myofibroblats. Moreover, tocilizumab sensitized TNBC cells to the cytotoxic effect of cisplatin in vitro. Furthermore, pharmacological inhibition of IL-6 by tocilizumab had great inhibitory effect on tumor growth and the EMT process in humanized orthotopic breast tumors in mice. In addition, tocilizumab potentiated the proapoptotic effect of cisplatin in humanized breast tumors. Together, these findings indicate that tocilizumab can suppress the prometastatic capacity of TNBC cells and enhances the cytotoxic effect of cisplatin against these cells. Therefore, tocilizumab could be of great therapeutic value for these hard-to-treat TNBC patients.

Physcion Enhances Sensitivity of Pancreatic Adenocarcinoma and Lung Carcinoma Cell Lines to Cisplatin

Cisplatin is one of the commonly used antitumor drugs for the treatment of different cancers. One of the mechanisms of cisplatin cytotoxicity is associated with oxidative stress initiation. Increased levels of the reactive oxygen species (ROS) are detected in many types of malignancies enhance the cells’ proliferative activity, but its excessively high levels can lead to apoptosis. Thus, one of the promising therapeutic strategies for cancer treatment is the regulation of intracellular ROS levels by targeted drugs. Physcion is an inhibitor of 6PGD enzyme which catalyzes the intracellular antioxidant NADPH formation (Lin et al. in Nature Cell Biology, 17(11), 1484–1496, 2015). In this study, the combined action of the cisplatin and Physcion on the ROS level and viability of human lung (H1299) and pancreatic cancer cell lines (AsPC-1) is described. It was shown that the combined action of Physcion with cisplatin caused a growth in the ROS level in H1299 and AsPC-1 cells up to 1.7 and 2.5 times, respectively, compared with cisplatin alone. Moreover, IC50 of the cisplatin in combination with Physcion decreased up to 1.6 times in the AsPC-1 cells and up to 2.2 times in Н1299 cells compared with cisplatin alone. The enhancing effect of Physcion on cisplatin cytotoxicity is supposedly associated with a ROS balance shift toward increase. Physcion could be considered as an adjunct compound for cancer treatment with DNA-damaging agents.

HIF-1\u03b1-dependent miR-424 induction confers cisplatin resistance on bladder cancer cells through down-regulation of pro-apoptotic UNC5B and SIRT4

BackgroundChemo-resistance of bladder cancer has been considered to be one of the serious issues to be solved. In this study, we revealed pivotal role of miR-424 in the regulation of CDDP sensitivity of bladder cancer cells.MethodsThe cytotoxicity of cisplatin and effect of miR-424 were assessed by flow cytometry and TUNEL. Transcriptional regulation of miR-424 by HIF-1α was assessed by Chromatin immunoprecipitation (ChIP). Effect of miR-424 on expression of UNC5B, SIRT4 (Sirtuin4) and apoptotic markers was measured by QRT-PCR and/or Western blot. The regulation of miR-424 for UNC5B and SIRT4 were tested by luciferase reporter assay. The 5637-inoculated nude mice xenograft model was used for the in vivo study. The clinical significance of miR-424 was demonstrated mainly through data mining and statistical analysis of TCGA.ResultsIn this study, we have found for the first time that cisplatin (CDDP) induces the expression of miR-424 in a HIF-1α-dependent manner under normoxia, and miR-424 plays a vital role in the regulation of CDDP resistance of bladder cancer cells in vitro. Mechanistically, we have found that UNC5B and SIRT4 are the direct downstream target genes of miR-424. CDDP-mediated suppression of xenograft bladder tumor growth was prohibited by the addition of miR-424, whereas ectopic expression of UNC5B or SIRT4 partially restored miR-424-dependent decrease in CDDP sensitivity of bladder cancer 5637 and T24 cells. Moreover, knockdown of UNC5B or SIRT4 prohibited CDDP-mediated proteolytic cleavage of PARP and also decreased CDDP sensitivity of these cells. Consistently, the higher expression levels of miR-424 were closely associated with the poor clinical outcome of the bladder cancer patients. There existed a clear inverse relationship between the expression levels of miR-424 and pro-apoptotic UNC5B or SIRT4 in bladder cancer tissues.ConclusionsCollectively, our current results strongly suggest that miR-424 tightly participates in the acquisition/maintenance of CDDP-resistant phenotype of bladder cancer cells through down-regulation of its targets UNC5B and SIRT4, and thus combination chemotherapy of CDDP plus HIF-1α/miR-424 inhibition might have a significant impact on hypoxic as well as normoxic bladder cancer cells.

MiRNA-181a-5p Enhances the Sensitivity of Cells to Cisplatin in Esophageal Adenocarcinoma by Targeting CBLB.

BackgroundCisplatin (CDDP) is extensively used for esophageal adenocarcinoma (EAC) chemotherapy, while cisplatin resistance is getting worse. microRNA-181a-5p (miR-181a-5p) has been reported to play an important role in various human cancers. However, the effect and underlying mechanism of miR-181a-5p in cisplatin resistance of EAC remain unclear.MethodsCisplatin-resistant EAC cells OE19/CDDP and parental sensitive OE19 cells were applied for experiments in vitro. The expressions of miR-181a-5p and CBLB were measured by quantitative real-time polymerase chain reaction (qRT-PCR) or Western blot. The cisplatin resistance of cells was expressed by cell viability, IC50 and apoptosis rate by using CCK-8 assay or flow cytometry. The interaction between miR-181a-5p and CBLB was evaluated by luciferase reporter assay and RIP assay. In vivo experiments were conducted via the murine xenograft model.ResultsmiR-181a-5p was highly expressed while CBLB was lowly expressed in OE19 cell lines compared with OE19/CDDP cells. In cisplatin-resistant OE19/CDDP cells, miR-181a-5p up-regulation or CBLB knockdown inhibited cell viability and inducted apoptosis. In cisplatin-sensitive OE19 cells, miR-181a-5p inhibition or CBLB overexpression promoted cell viability and suppressed apoptosis. CBLB was confirmed to be a target of miR-181a-5p, and rescue assay showed CBLB overexpression reversed the suppression of OE19/CDDP cell viability induced by miR-181a-5p up-regulation, and its down-regulation attenuated miR-181a-5p-inhibition-mediated enhancement of OE19 cell viability. In addition, miR-181a-5p up-regulation enhanced the cytotoxicity of cisplatin in EAC in vivo.ConclusionmiR-181a-5p enhanced the sensitivity of cells to cisplatin in EAC by targeting CBLB, indicating a promising sensitizer of cisplatin therapy in clinical esophageal cancer.

Literature Review: Mekanisme Resistensi Kemoterapi Berbasis Platinum

Cisplatin is a type of platinum-based chemotherapy that is often used in the spectrum of solid neoplasms, including the ovaries, testicles, urinary vesicles, colorectal, lungs, and head-neck. The clinical success of platinum-based chemotherapy, however, is limited to side effects and the incidence of treatment resistance. Resistance has limited the efficacy of these agents in most diseases, so further knowledge is needed on how the resistance mechanism can occur so that further development can be carried out. Molecular mechanism of cisplatin resistance. Malignant cells can lose their sensitivity to the cytostatic/cytotoxic activity of cisplatin as a result of genetic or epigenetic damage. These changes can affect processes that precede the actual binding of cisplatin to its targets (pre-target resistance), potentiating the cell's ability to repair molecular damage caused by cisplatin (resistance at the target level) and damaging the signal transmission that usually imparts damage caused by cisplatin in apoptosis (post-target resistance) or stimulates pro-survival signaling that counteracts the cytotoxicity of cisplatin even though it usually does not occur by this drug (target resistance).

Cytotoxic dimeric half‐sandwich Ru(II), Os(II) and Ir(III) complexes containing the 4,4′‐biphenyl‐based bridging ligands

A series of dinuclear half‐sandwich Ru(II), Os(II) and Ir(III) complexes [Ru2(μ‐Ln)(η6‐pcym)2Cl2](PF6)2 (1, 4), [Os2(μ‐Ln)(η6‐pcym)2Cl2](PF6)2 (2, 5) and [Ir2(μ‐Ln)(η5‐Cp*)2Cl2](PF6)2 (3, 6), based on 4,4′‐biphenyl‐based bridging Schiff base ligands N,N′‐(biphenyl‐4,4′‐diyldimethylidyne)bis‐2‐(pyridin‐2‐yl)methanamine (L1; for 1–3) and N,N′‐(biphenyl‐4,4′‐diyldimethylidyne)bis‐2‐(pyridin‐2‐yl)ethanamine (L2; for 4–6) is reported; pcym = 1‐methyl‐4‐(propan‐2‐yl)benzene, Cp* = pentamethylcyclopentadienyl. The complexes were characterized by relevant analytical techniques (i.e. elemental analysis, FT‐IR, NMR, ESI‐MS), and their in vitro cytotoxicity was assessed at six cancerous and two non‐cancerous (healthy) human cell lines. Overall, complexes 4–6, containing the L2 bridging ligand, revealed higher cytotoxicity as compared with 1–3 and, thus, they were studied in greater detail. The best‐performing complex 6 exceeded at least twice the in vitro cytotoxicity of cisplatin and showed high selectivity towards the cancer cells over the normal ones, including the primary culture of human hepatocytes. In contrast to cisplatin, complexes 4–6 did not induce the cell cycle modification of the treated A2780 human ovarian carcinoma cells (studied by flow cytometry and Western blot analysis). High levels of superoxide anion were induced by complexes 4–6 at the A2780 cells. The levels of activated forms of Caspase‐3 and Caspase‐8 at the A2780 cells treated by Ru(II) complex 4 were comparable with cisplatin, while complexes 5 and 6 had only a minor effect on activation of these caspases.

The modulatory effect of septilin on cytotoxicity of cisplatin in a human breast adenocarcinoma cell line

Cisplatin (Csp) is a recurrently used chemotherapeutic drug but its use is inadequate due to undesirable adverse effects. In search of alternative medicine more attention has been given to phytochemicals. Septilin (Spt), a polyherbal drug and its therapeutic potential is huge but there is a scarcity of studies on its cytotoxic potential on cancer cells. The current study was designed to examine the effects of Spt in combination with Csp on human breast adenocarcinoma (MCF-7) and normal human breast epithelial (MCF-10A) cell lines. Cell viability for Spt treated cells was studied using MTT assay. IC50 value of Csp on MCF-7 cells was found to be 10 μg/mL at 24 h. This dose was further used to study the combined effects of Csp with Spt on MCF-7 and MCF-10A cell lines. Maximum cytotoxicity of Spt on MCF-7 cells was observed at Spt 5 μg/mL. The mechanism of Spt induced cytotoxicity was studied using apoptosis assay. Spt did not show any cytotoxic effects on MCF-10 A normal human breast epithelial cells, indicating Spt has no effect on normal cells. Our findings suggest that Spt can be used in combination with an anticancer drug Csp to increase its efficacy and/or to minimize its side effects on normal cells.

Ginsenoside Rh2 Improves the Cisplatin Anti-tumor Effect in Lung Adenocarcinoma A549 Cells via Superoxide and PD-L1.

Ginsenoside Rh2 (Rh2) is a major biological component of ginseng that exerts antitumor activities in multiple cancers including Non-Small Cell Lung Cancers (NSCLCs). Rh2 also enhances the anti-tumor effects of various chemotherapy drugs including cisplatin at relatively low concentrations. Here, the mechanistic role of Rh2 in chemotherapy-treated NSCLCs will be investigated. In this study, FACS, western blot and siRNA addition were used to analyze the role of Rh2 in cisplatin- treated lung adenocarcinoma A549 and H1299 cells. Subsequent observations indicated that Rh2 enhanced cisplatin-induced NSCLCs A549 and H1299 cells apoptosis. Cisplatin-induced productive autophagy was repressed by Rh2 in A549 cells. Rh2 also enhanced cisplatin cytotoxicity by elevating superoxide dismutase activity and repressing cisplatin-induced superoxide generation. Conversely, Rh2 was found to repress cisplatin-induced phosphorylation of epidermal growth factor receptor, phosphoinositide 3-kinase, protein kinase B, and autophagy. Cisplatin-induced Programmed Death- Ligand 1 (PD-L1) expression was repressed by Rh2 via the superoxide. These findings suggest that Rh2 enhanced the function of cisplatin by repressing superoxide generation, PD-L1 expression, and autophagy in lung adenocarcinoma cells.

SIRT2 protects peripheral neurons from cisplatin-induced injury by enhancing nucleotide excision repair.

Platinum-based chemotherapy-induced peripheral neuropathy is one of the most common causes of dose reduction and discontinuation of life-saving chemotherapy in cancer treatment; it often causes permanent impairment of quality of life in cancer patients. The mechanisms that underlie this neuropathy are not defined, and effective treatment and prevention measures are not available. Here, we demonstrate that SIRT2 protected mice against cisplatin-induced peripheral neuropathy (CIPN). SIRT2 accumulated in the nuclei of dorsal root ganglion sensory neurons and prevented neuronal cell death following cisplatin treatment. Mechanistically, SIRT2, an NAD+-dependent deacetylase, protected neurons from cisplatin cytotoxicity by promoting transcription-coupled nucleotide excision repair (TC-NER) of cisplatin-induced DNA cross-links. Consistent with this mechanism, pharmacological inhibition of NER using spironolactone abolished SIRT2-mediated TC-NER activity in differentiated neuronal cells and protection of neurons from cisplatin-induced cytotoxicity and CIPN in mice. Importantly, SIRT2's protective effects were not evident in lung cancer cells in vitro or in tumors in vivo. Taken together, our results identified SIRT2's function in the NER pathway as a key underlying mechanism of preventing CIPN, warranting future investigation of SIRT2 activation-mediated neuroprotection during platinum-based cancer treatment.

Bioinformatics and In Vitro Studies Reveal the Importance of p53, PPARG and Notch Signaling Pathway in Inhibition of Breast Cancer Stem Cells by Hesperetin.

Purpose: The failure of chemotherapy in breast cancer is caused by breast cancer stem cells (BCSCs), a minor population of cells in bulk mammary tumors. Previously, hesperetin, a citrus flavonoid, showed cytotoxicity in several cancer cells and increased cytotoxicity of doxorubicin and cisplatin. Hesperetin also inhibited osteogenic and adipocyte differentiation, however, a study of the effect of hesperetin on BCSCs has not yet been performed. Methods: In this study, we combined bioinformatics and in vitro works. A bioinformatic approach was performed to identify molecular targets, key proteins, and molecular mechanisms of hesperetin targeted at BCSCs, and genetic alterations among key genes. In addition, an in vitro study was carried out to measure the effects of hesperetin on BCSCs using the spheroids model of MCF-7 breast cancer cells (mammospheres). Results: Using a bioinformatics approach, we identified P53, PPARG, and Notch signaling as potential targets of hesperetin in inhibition of BCSCs. The in vitro study showed that hesperetin exhibits cytotoxicity on mammospheres, inhibits mammosphere and colony formation, and inhibits migration. Hesperetin modulates the cell cycle and induces apoptosis in mammospheres. Moreover, hesperetin treatment modulates the expression of p53, PPARG, and NOTCH1. Conclusion: Taken together, hesperetin has potential for the treatment of BCSC by targeting p53, PPARG and Notch signaling. Further investigation of the molecular mechanisms involved is required for the development of hesperetin as a BCSC-targeted drug.

Hypoxia potentiates the capacity of melanoma cells to evade cisplatin and doxorubicin cytotoxicity via glycolytic shift.

The hypoxic environment within solid tumors impedes the efficacy of chemotherapeutic treatments. Here, we demonstrate that hypoxia augments the capacity of melanoma cells to withstand cisplatin and doxorubicin cytotoxicity. We show that B16F10 cells derived from spontaneously formed melanoma and YUMM1.7 cells, engineered to recapitulate human‐relevant melanoma driver mutations, profoundly differ in their vulnerabilities to cisplatin and doxorubicin. The differences are manifested in magnitude of proliferative arrest and cell death rates, extent of mtDNA depletion, and impairment of mitochondrial respiration. In both models, cytotoxicity is mitigated by hypoxia, which augments glycolytic metabolism. Collectively, the findings implicate metabolic reprogramming in drug evasion and suggest that melanoma tumors with distinct genetic makeup may have differential drug vulnerabilities, highlighting the importance of precision anticancer treatments.

Pichia fermentans originates apoptosis in human oral squamous cell carcinoma by over-expressing BAX and CASP 9 genes.

Squamous cell carcinoma (SCC) is one of the most common malignant tumors of the oral cavity. Probiotics have often been considered as effective anti-tumoral candidates. This study aimed to investigate the role of Pichia fermentans YSH secretion metabolites on the induction of apoptosis in SCC. Cytotoxicity, apoptotic effects, and visualization DNA damage were evaluated by MTT, flow cytometry, and DAPI staining assays, respectively. Real-time PCR was employed for evaluation of the mechanism of cellular apoptosis. P. fermentans YSH secretions (IC50) showed cellular cytotoxicity in human tongue squamous carcinoma (HSC4, RRID:CVCL_1289) cells (85% apoptosis) similar to the cytotoxicity of cisplatin whereas only 21% apoptosis was observed in human epithelial normal (KDR, RRID:CVCL_9V14) cells. The prophylactic efficacy of reference yeast, which regarded as a reference, was not comparable to P. fermentans YSH illustrating strain-dependent properties of bioactivities on oral disease control and prevention. According to our result, the main cytotoxicity is related to apoptosis mechanisms induced by apoptosis genes inducing BAX and CASP. However, follow-up researches should be performed to recognize the compounds to be utilized as effective anticancer therapeutics.

RIP1 promotes proliferation through G2/M checkpoint progression and mediates cisplatin-induced apoptosis and necroptosis in human ovarian cancer cells.

Receptor-interacting protein 1 (RIP1, also known as RIPK1) is not only a tumor-promoting factor in several cancers but also mediates either apoptosis or necroptosis in certain circumstances. In this study we investigated what role RIP1 plays in human ovarian cancer cells. We showed that knockout (KO) of RIP1 substantially suppressed cell proliferation, accompanied by the G2/M checkpoint arrest in two human ovarian cancer cell lines SKOV3 and A2780. On the other hand, RIP1 KO remarkably attenuated cisplatin-induced cytotoxicity, which was associated with reduction of the apoptosis markers PARP cleavage and the necroptosis marker phospho-MLKL. We found that RIP1 KO suppressed cisplatin-induced ROS accumulation in both SKOV3 and A2780 cells. ROS scavenger BHA, apoptosis inhibitor Z-VAD or necroptosis inhibitor NSA could effectively suppress cisplatin’s cytotoxicity in the control cells, suggesting that ROS-mediated apoptosis and necroptosis were involved in cisplatin-induced cell death. In addition, blocking necroptosis with MLKL siRNA effectively attenuated cisplatin-induced cytotoxicity. In human ovarian cancer A2780 cell line xenograft nude mice, RIP1 KO not only significantly suppressed the tumor growth but also greatly attenuated cisplatin’s anticancer activity. Our results demonstrate a dual role of RIP1 in human ovarian cancer: it acts as either a tumor-promoting factor to promote cancer cell proliferation or a tumor-suppressing factor to facilitate anticancer effects of chemotherapeutics such as cisplatin.

Multiparametric analysis of the effectiveness of cisplatin on cutaneous squamous carcinoma cellsusing two different types of adjuvants.

The objective of this study was to regulate the cytotoxicity of cisplatin (cisPt) minimizing its adverse effects. For this purpose, the lowest cisPt concentration needed to obtain a significant positive response in cutaneous squamous cell carcinoma (cSCC) was explored. Two adjuvant agents as gold nanoparticles (AuNP) and chelating tricine were tested as enhancers in cisPt treatment. Effectiveness of all treatments was assessed by means of biochemical techniques, which offer quantitative data, as well as two microscopy–based techniques that provided qualitative cell imaging. The present work confirms the effectiveness of free cisplatin at very low concentrations. In order to enhance its effectiveness while the side effects were probably diminished, cisPt 3.5 μM was administered with AuNP 2.5 mM, showing an effectiveness practically equal to that observed with free cisPt. However, the second treatment investigated, based on cisPt 3.5 μM combined with tricine 50 mM, enhanced drug effectiveness, increasing the percentage of cells dying by apoptosis. This treatment was even better in terms of cell damage than free cisPt at 15 μM. Images obtained by TEM and cryo-SXT confirmed these results, since a notable number of apoptotic bodies were detected when cisPt was combined with tricine. Thus, tricine was clearly a better adjuvant for cisPt treatments.

ROS enhances the cytotoxicity of cisplatin by inducing apoptosis and autophagy in tongue squamous cell carcinoma cells.

Cisplatin is one of the most widely used anticancer agents for patients with tongue squamous cell carcinoma (TSCC), but its efficacy is limited by chemoresistance. Accumulated evidence has demonstrated that reactive oxygen species (ROS) plays a critical role in multiple tumor chemotherapy resistance. In the present study, we aimed to investigate the role of ROS in cisplatin resistance of TSCC and explore its underlying molecular mechanism in vitro. Our results showed that pre-treatment with ROS scavenger N-acetylcysteine reduced cisplatin-induced cytotoxicity, autophagy, and apoptosis in TSCC cells. Down-regulation of intracellular ROS attenuated apoptosis and autophagy of TSCC cisplatin-resistant CAL27/CDDP cells by reversing the inhibition of p38MAPK/mTOR pathway. Taken together, these findings suggest that down-regulation of intracellular ROS reduces the cytotoxicity of cisplatin by inhibiting apoptosis and autophagy in TSCC cells involving p38MAPK/mTOR mediated pathway. Low intracellular ROS levels may be one of the main mechanisms of cisplatin resistance in TSCC.