Antitumor Activity Of Cisplatin Research Articles

The effect of m6A methyltransferase METTL3 mediated TMEM30A regulation on tumor energy metabolism and cisplatin anti-tumor activity in oral squamous cell carcinoma

AimsCisplatin (CDDP) is still one of the most commonly used first-line treatments for advanced and recurrent oral squamous cell carcinoma (OSCC) patients in clinical practice. However, the decrease in tumor sensitivity to CDDP weakens its therapeutic effect. There is still limited research on the effect of METTL3-mediated methylation of m6A on CDDP sensitivity in OSCC. TMEM30A widely exists in biomembranes and regulates the lipid asymmetry of the membrane, but there is no report on its function in OSCC. This study aims to explore the specific mechanism by which METTL3 regulates m6A methylation of TMEM30A and affects the occurrence and development of OSCC, and further investigate the effects of METTL3 and TMEM30A on the anti-tumor activity of CDDP. Key findingsIn OSCC, METTL3 plays a pro-cancer role and weakens the anti-tumor efficacy of CDDP; METTL3 positively regulates the expression of TMEM30A by m6A methylation modification and binding to TMEM30A; The abnormally high expression of TMEM30A in OSCC not only weakens CDDP sensitivity, but also enhances the malignant evolution of cancer cells, regulates the metabolic balance of ATP and lactate in cells, and is a potential oncogenic gene. SignificanceTMEM30A promotes malignant progression of tumors through METTL3 mediated m6A methylation modification, participates in maintaining the balance of tumor ATP and lactate metabolism, and reduces the anti-tumor activity of CDDP. TMEM30A is a potential gene target for CDDP anti-tumor activity in OSCC.

FDA-Approved Tedizolid Phosphate Prevents Cisplatin-Induced Hearing Loss Without Decreasing Its Anti-tumor Effect.

Cisplatin is a low-cost clinical anti-tumor drug widely used to treat solid tumors. However, its use could damage cochlear hair cells, leading to irreversible hearing loss. Currently, there appears one drug approved in clinic only used for reducing ototoxicity associated with cisplatin in pediatric patients, which needs to further explore other candidate drugs. Here, by screening 1967 FDA-approved drugs to protect cochlear hair cell line (HEI-OC1) from cisplatin damage, we found that Tedizolid Phosphate (Ted), a drug indicated for the treatment of acute infections, had the best protective effect. Further, we evaluated the protective effect of Ted against ototoxicity in mouse cochlear explants, zebrafish, and adult mice. The mechanism of action of Ted was further explored using RNA sequencing analysis and verified. Meanwhile, we also observed the effect of Ted on the anti-tumor effect of cisplatin. Ted had a strong protective effect on hair cell (HC) loss induced by cisplatin in zebrafish and mouse cochlear explants. In addition, when administered systemically, it protected mice from cisplatin-induced hearing loss. Moreover, antitumor studies showed that Ted had no effect on the antitumor activity of cisplatin both in vitro and in vivo. RNA sequencing analysis showed that the otoprotective effect of Ted was mainly achieved by inhibiting phosphorylation of ERK. Consistently, ERK activator aggravated the damage of cisplatin to HCs. Collectively, these results showed that FDA-approved Ted protected HCs from cisplatin-induced HC loss by inhibiting ERK phosphorylation, indicating its potential as a candidate for preventing cisplatin ototoxicity in clinical settings.

Structural characterization of a sulfated polysaccharide from Gracilariopsis lemaneiformis and its potentiation of cisplatin antitumor activity in Colon-26 carcinoma tumor-bearing mice by inducing ferroptosis.

Ferroptosis, a form of regulated cell death caused by iron-mediated lipid peroxidation, has become a potential strategy to overcome drug resistance and improve the efficacy of traditional cancer treatments. In this study, we investigated whether treatment with the combination of Gracilariopsis lemaneiformis polysaccharides and cisplatin (CP) potentiated the antitumor activity in a Colon-26 carcinoma tumor-bearing mouse model by ferroptosis activation. The G. lemaneiformis polysaccharide GP90 was mainly composed of (1→3) linked 4-O-sulfate-β-D-galactose and (1→4) linked 3,6-anhydro-α-L-galactose with a molecular weight of 12.45 kDa. Compared with the CP group, the combination of GP90 and CP significantly suppressed tumor growth. Based on the transcriptomic and metabolomic analyses of tumor tissue, GP90 enhanced the antitumor effect of CP by promoting ferroptosis and regulating ferroptosis-related metabolic pathways. Moreover, the accumulation of 4-hydroxy-2-nonenal (4-HNE) and down-regulation of the expression of solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (Gpx4) were verified by immunohistochemistry staining. Finally, gene set enrichment analysis showed that positive immunoregulatory pathways were significantly enriched in the GP90 and CP combination group. Our results indicate that GP90 potentiates chemotherapy sensitivity by targeting the transferrin receptor and SLC7A11/Gpx4 pathway to induce ferroptosis, which might be a useful therapeutic target in colorectal cancer patients.

A PROSPECTIVE STUDY ON DAILY LOW DOSE CISPLATIN CONCURRENT WITH INTENSITY MODULATED RADIOTHERAPY IN LOCALLY ADVANCED CARCINOMA CERVIX

Treatment of locally advanced cervical cancer evolved from EBRT alone to EBRT plus ICRT to EBRT with concurrent chemotherapy plus ICRT. Concurrent cisplatin therapy is usually administered on a weekly or three weekly basis. The doses of Cisplatin used in the weekly or three weekly regimen may not be tolerated well by all patients, resulting to fewer patients being able to receive the total planned effective dose of concurrent chemotherapy. Experimental data suggest that antitumor activity of cisplatin may be greater if administered by continuous infusion. Preliminary studies have also shown that low dose, daily Cisplatin with radiotherapy may be better tolerated along with similar response rates, especially in older age patients. Results: Overall 96.8 % (30 out of 31) of the patients had complete response and 3.2% (1 out of 31) patients had partial response. Almost all (except one) the patients in the study received a cumulative dose of 200 mg/m2 of concurrent Cisplatin. Acute grade 3 toxicities were observed mostly in the form of diarrhoea and skin toxicity. Grade 3 diarrhoea occurred in 14 patients (45.2%). Incidence of acute grade 3 skin reaction was seen in 2 patients (6.5%), whereas the incidence of acute grade 3 haematological toxicity , genitourinary toxicity and grade 3 nausea and vomiting was nil. Conclusions: Adaily low dose cisplatin prior to radiotherapy might lead to an increased radiosensitization as well as better tolerance than other regimens.

Novel PHD2/HDACs hybrid inhibitors protect against cisplatin-induced acute kidney injury

Acute kidney injury (AKI) is associated with high morbidity and mortality. Cisplatin is a common chemotherapeutic, but its nephrotoxicity-driven AKI limits its clinical application. Currently, there are no specific and satisfactory therapies in the clinic for AKI. Inhibitors of hypoxia-inducible factor prolyl hydroxylase 2 (HIF-PHD2) or histone deacetylase (HDACs) had shown renoprotective effects against AKI in preclinical studies. This study aimed to develop a novel therapeutic to prevent AKI progression by targeting PHD2 and HDACs simultaneously. We designed and synthesized a series of PHD2/HDACs hybrid inhibitors. The initial drug activity screening identified a candidate compound 31c, which exhibited potent inhibitory activities against PHD2 and HDAC1/2/6. Cellular analyses further showed that 31c did not affect cisplatin's antitumor activity in cancer cells but strongly protected cisplatin-induced toxicity on HK-2 cells. In vivo studies with the cisplatin-induced AKI mouse model demonstrated that 31c remarkably alleviated kidney dysfunction with suppressed plasma BUN/SCr and increased EPO levels. The potent renoprotective effects of 31c on AKI were confirmed by significant improvements in pathological kidney conditions in the mouse model. These results suggest that the novel PHD2/HDACs hybrid inhibitor, 31c, has a clinical potential as the renoprotective agent for the treatment/prevention of cisplatin-induced AKI for various cancers.

Curcumin and its derivatives in cancer therapy: Potentiating antitumor activity of cisplatin and reducing side effects.

Curcumin is a phytochemical isolated from Curcuma longa with potent tumor-suppressor activity, which has shown significant efficacy in pre-clinical and clinical studies. Curcumin stimulates cell death, triggers cycle arrest, and suppresses oncogenic pathways, thereby suppressing cancer progression. Cisplatin (CP) stimulates DNA damage and apoptosis in cancer chemotherapy. However, CP has adverse effects on several organs of the body, and drug resistance is frequently observed. The purpose of the present review is to show the function of curcumin in decreasing CP's adverse impacts and improving its antitumor activity. Curcumin administration reduces ROS levels to prevent apoptosis in normal cells. Furthermore, curcumin can inhibit inflammation via down-regulation of NF-κB to maintain the normal function of organs. Curcumin and its nanoformulations can reduce the hepatoxicity, neurotoxicity, renal toxicity, ototoxicity, and cardiotoxicity caused by CP. Notably, curcumin potentiates CP cytotoxicity via mediating cell death and cycle arrest. Besides, curcumin suppresses the STAT3 and NF-ĸB as tumor-promoting pathways, to enhance CP sensitivity and prevent drug resistance. The targeted delivery of curcumin and CP to tumor cells can be mediated nanostructures. In addition, curcumin derivatives are also able to reduce CP-mediated side effects, and increase CP cytotoxicity against various cancer types.

Abstract CT115: Phase I trial of the triplet berzosertib (M6620, VX-970), veliparib and cisplatin (BVP) in patients with advanced solid tumors

Abstract Background: Ataxia-telangiectasia-related (ATR) protein kinase is central to the repair of damaged DNA through the homologous recombination (HR) pathway. We conducted a phase I trial of cisplatin in combination with the ataxia-telangiectasia-related (ATR) protein kinase inhibitor berzosertib (M6620) and the poly (ADP-ribose) polymerase (PARP) 1/2 inhibitor veliparib, postulating that simultaneous PARP and ATR inhibition impairs DNA repair and induces a “BRCA null”-like phenotype which could potentiate the antitumor activity of cisplatin. We evaluated the safety, maximal tolerated dose (MTD) and preliminary anti-tumor activity of this treatment triplet. The study was conducted through the Experimental Therapeutics Clinical Trials Network (ETCTN). Methods: This open label trial used a 3+3 design. Cisplatin and berzosertib were each administered intravenously on separate, sequential days for two continuous weeks [day (D) 1 and 8; D2 and 9 respectively], together with veliparib orally twice daily during IV therapy and for 24 hours after (D1-3 and 8-10) in 21-day cycles. Prior platinum and PARP inhibitor therapy were permitted. Tumor expression of DNA damage repair (DDR) biomarkers was assessed at the MTD using validated, quantitative immunofluorescence assays. Results: Fifty-three patients (pts) enrolled, 46 pts evaluable for response. The MTD and RP2D dose is cisplatin 40 mg/m2 D1 and D8, berzosertib 210 mg/m2 D2 and D9, and veliparib 200mg BID (D1-3, D8-10). Three patients achieved a confirmed partial response (PR; 5.6%). A further 2 patients had an unconfirmed PR (breast carcinoma, -30%; HGS carcinoma, -36%). Four responders (3 PR and 1 uPR) received prior platinum. Median time on study: 4 cycles (range 1-25). Genomic data was available on four pts achieving a response: ovarian cancer (BRCA-wildtype, ATM unknown; 25 cycles), breast carcinoma (ATM mutation; 14 cycles), SCC of the tongue (Chek2 mutation; 20 cycles), and HGS carcinoma (ATM/BRIP1 mutation; 4 cycles). Twenty-six pts (56.5%) had stable disease. Thirty-five patients (66.0%) required dose reduction in at least 1 agent, most commonly veliparib (25; 47.2%). Most common grade 3 and 4 adverse events were related to myelosuppression: anemia (20; 37.7%), thrombocytopenia (17; 32.1%), leukopenia (13; 24.5%), neutropenia (12; 22.6%), and lymphopenia (11; 20.8%). Ongoing pharmacodynamic analyses of tumor biopsies collected on C1D1 (post-veliparib/cisplatin) and C1D9 (post-veliparib/cisplatin/M6620) have demonstrated a combination-induced increase in RAD51, indicative of replication stress. Conclusions: The BVP combination shows anti-tumor activity in HR-compromised tumors and M6620 further increases the DDR response elicited by combination cisplatin/veliparib. Citation Format: Geraldine O'Sullivan Coyne, Khanh T. Do, Shivaani Kummar, Naoko Takebe, Sarina Piha-Paul, Richard Piekarz, Deborah Wilsker, Brandon Miller, Katherine Ferry-Galow, Ralph Parchment, Lamin Juwara DNP, Mary Jane Ong, Arjun Mittra, James H. Doroshow, Alice P. Chen. Phase I trial of the triplet berzosertib (M6620, VX-970), veliparib and cisplatin (BVP) in patients with advanced solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT115.

VDAC1 as a target in cisplatin anti-tumor activity through promoting mitochondria fusion

Cisplatin is one of the most effective anti-cancer drugs, but its efficacy is limited by the development of resistance. Previous studies have shown that mitochondria play critical roles in cisplatin cytotoxicity, however, the exact mechanism of mitochondria involved in cisplatin sensitivity has not been clarified. In this study, cisplatin triggered mitochondrial oxidative stress and the decrease of mitochondria membrane potential in human cervical cancer cells. Then we screened a series of mitochondrial relevant inhibitors, including mitochondrial mPTP inhibitors DIDS and CsA, and mitochondrial respiratory complex inhibitors Rot and TTFA. Among these, only DIDS, as the inhibitor of mitochondrial outer membrane protein VDAC1, showed strong antagonism against cisplatin toxicity. DIDS mitigated cisplatin-induced MFN1-dependent mitochondrial fusion, mitochondrial dysfunction and oxidative damage. These findings demonstrated that VDAC1 may serve as a potential therapeutic target in the increase sensitivity of cisplatin, which provides an attractive pharmacological therapy to improve the effectiveness of chemotherapy.

Inhibition of dual leucine zipper kinase prevents chemotherapy-induced peripheral neuropathy and cognitive impairments.

Chemotherapy-induced peripheral neuropathy (CIPN) and chemotherapy-induced cognitive impairments (CICI) are common, often severe neurotoxic side effects of cancer treatment that greatly reduce quality of life of cancer patients and survivors. Currently, there are no Food and Drug Administration-approved agents for the prevention or curative treatment of CIPN or CICI. The dual leucine zipper kinase (DLK) is a key mediator of axonal degeneration that is localized to axons and coordinates the neuronal response to injury. We developed a novel brain-penetrant DLK inhibitor, IACS'8287, which demonstrates potent and highly selective inhibition of DLK in vitro and in vivo. Coadministration of IACS'8287 with the platinum derivative cisplatin prevents mechanical allodynia, loss of intraepidermal nerve fibers in the hind paws, cognitive deficits, and impairments in brain connectivity in mice, all without interfering with the antitumor activity of cisplatin. The protective effects of IACS'8287 are associated with preservation of mitochondrial function in dorsal root ganglion neurons and in brain synaptosomes. In addition, RNA sequencing analysis of dorsal root ganglia reveals modulation of genes involved in neuronal activity and markers for immune cell infiltration by DLK inhibition. These data indicate that CIPN and CICI require DLK signaling in mice, and DLK inhibitors could become an attractive treatment in the clinic when coadministered with cisplatin, and potentially other chemotherapeutic agents, to prevent neurotoxicities as a result of cancer treatment.

Cisplatin Cytotoxicity in Human Testicular Germ Cell Tumor Cell Lines Is Enhanced by the CDK4/6 Inhibitor Palbociclib.

Cisplatin-based chemotherapy is the mainstay of pharmacological treatment of testicular germ cell tumors (TGCTs) that, together with early diagnosis, surgery, and/or radiotherapy, has dramatically improved the prognosis. However, under the pressure of such pharmacological therapy (both classical cytotoxic drugs and targeted therapy), cancer cells may develop resistance. Thus, combination therapy that may include cytotoxic drugs and targeted therapy could offer an advantage to curing cancers. Here, we investigated the in vitro and in vivo antitumor activity of cisplatin, as a single-agent or in combination with palbociclib. The cell viability of Ntera-2/cl.D1 (NT2/D1) and 833K after exposure to palbociclib and/or cisplatin was evaluated by MTT dye reduction assay and by ATPLite Luminescence Assay. Gene and protein expression was evaluated by quantitative reverse transcription polymerase chain reaction and by western blot. Flow cytometric cell-cycle analysis was performed, as well. The in vivo experiments were conducted on NT2/D1 xenografts in AB zebrafish embryos exposed to the drugs. Palbociclib and cisplatin decreased TGCT cell viability both in vitro and in vivo. This effect was additive when cells were exposed to the drug combination. In the NT2/D1 cell lines, the drug combination also exerted a positive effect with regard to delaying cell recovery after the toxic insult. In the combination experiments, cisplatin-induced cell accumulation in G2/M was predominant compared with the palbociclib effect. These results could provide the rationale for developing further studies to improve the pharmacological treatment of TGCTs, but they must be demonstrated in a dedicated clinical trial.

Lung cancer cells and their sensitivity/resistance to cisplatin chemotherapy: Role of microRNAs and upstream mediators

Cisplatin (CP) is a well-known chemotherapeutic agent with excellent clinical effects. The anti-tumor activity of CP has been demonstrated in different cancers such as breast, cervical, reproductive, lung, brain, and prostate cancers. However, resistance of cancer cells to CP chemotherapy has led to its failure in eradication of cancer cells, and subsequent death of patients with cancer. Fortunately, much effort has been put to identify molecular pathways and mechanisms involved in CP resistance/sensitivity. It seems that microRNAs (miRs) are promising candidates in mediating CP resistance/sensitivity, since they participate in different biological aspects of cells such as proliferation, migration, angiogenesis, and differentiation. In this review, we focus on miRs and their regulation in CP chemotherapy of lung cancer, as the most malignant tumor worldwide. Oncogenic miRs trigger CP resistance in lung cancer cells via targeting various pathways such as Wnt/β-catenin, Rab6, CASP2, PTEN, and Apaf-1. In contrast, onco-suppressor miRs inhibit oncogene pathways such as STAT3 to suppress CP resistance. These topics are discussed to determine the role of miRs in CP resistance/sensitivity. We also describe the upstream modulators of miRs such as lncRNAs, circRNAs, NF-κB, SOX2 and TRIM65 and their association with CP resistance/sensitivity in lung cancer cells. Finally, the effect of anti-tumor plant-derived natural compounds on miR expression during CP sensitivity of lung cancer cells is discussed.

Co-Administration of Fendiline Hydrochloride Enhances Chemotherapeutic Efficacy of Cisplatin in Neuroblastoma Treatment.

Despite significant improvement of neuroblastoma (NB) patients’ survival due to recent treatment advancements in recent years, NB is still associated with high mortality rate. In search of novel strategies to increase NB’s susceptibility to pharmacological treatments, we investigated the in vitro and in vivo effects of fendiline hydrochloride as an enhancer of cisplatin antitumor activity. To assess the modulation of fendiline treatment on cisplatin responses, we used in vitro (evaluating NB cell proliferation by XCELLigence technology and colony formation, and gene expression by RT-PCR) and in vivo (NB cell grafts in NOD-SCID mice) models of NB. NB cell treatment with fendiline induced the expression of the ncRNA NDM29, leading to cell differentiation and to the reduction of the expression of MDRs/ABC transporters linked to multidrug resistance. These events were correlated to higher NB cell susceptibility to cisplatin and, consequently, increased its cytotoxic potency. In vivo, this drug interaction causes an enhanced ability of cisplatin to induce apoptosis in NB masses, resulting in tumor growth reduction and prolonged animal survival rate. Thus, the administration of fendiline might be a possible novel therapeutic approach to increase cisplatin efficacy in aggressive and poorly responsive NB cases.

Targeting Aurora A Kinase (AAK) in Platinum-Resistant High Grade Serous Ovarian Cancer.

Aurora A kinase (AAK) involved in G2-M transition is functionally involved in centrosome maturation and maintaining an active spindle assembly checkpoint. We tested the hypothesis that in platinum-taxane resistant high grade serous ovarian cancer (HGSOC) inhibition of AAK involved in G2-M transition would enhance the anti-tumor activity of cisplatin (CP) or paclitaxel (PT). Using HGSOC cell lines from platinum-taxane refractory patients that do not harbor BRCA1/2 mutations, we tested the anti-tumor activity of CP, or PT alone or in combination with the AAK inhibitor alisertib (AL). Treatment with CP for 3 h or PT for 6 h followed sequentially by AL for 48 h led to a significant decrease in cell survival (p < 0.001) compared to treatment with either drug alone in HGSOC cells but not in immortalized normal human ovarian surface epithelium or normal human fallopian tube secretory epithelium cells. The treatment with CP or PT followed by AL also led to a significant increase in reactive oxygen species (p < 0.05), apoptosis (p < 0.001) and accumulation of cells in G2/M that was accompanied by a modest increase in expression of AAK. Downregulation of AAK, but not aurora B kinase, with targeted siRNAs also significantly enhanced apoptosis by CP or PT, suggesting that AL specifically targeted AAK. In summary, in HGSOC without BRCA1/2 mutations, CP, or PT resistance can potentially be circumvented by sequential treatment with AL that inhibits AAK involved in G2-M transition.

Abstract 5830: Senolytic drug ABT-263 enhances cisplatin- and TIL-induced cell death in vitro but has limited in vivo activity in preclinical models of head and neck cancer

Abstract Background/Objectives: Cisplatin and other cytotoxic chemotherapy drugs may induce senescence, rather than cell death, at sublethal doses. We hypothesized that the senolytic drug ABT-263 (navitoclax) might enhance cisplatin cytotoxicity and anti-tumor immunity in preclinical models of head and neck squamous cell carcinoma (HNSCC). Methods/Results: When human HNSCC cell lines were treated with sublethal doses of cisplatin for 72 hours, they expressed increased levels of senescence markers p16 and beta-galactosidase. In additional experiments, cells were rendered senescent with cisplatin and then treated for another 72 hours with navitoclax, which enhanced cisplatin-induced cell death. Three different cisplatin-sensitive syngeneic mouse models were then used to investigate whether the addition of navitoclax can enhance cisplatin-induced tumor cell death in vivo. Mice were treated with weekly cycles consisting of cisplatin on day 1 (5-6 mg/kg IP) followed by navitoclax on days 3, 4, and 5 (100 mg/kg, OG). The addition of navitoclax caused an early, very slight improvement in tumor growth delay in the TC-1 model, but not in the MEER or MOC1 models. We next investigated whether navitoclax might enhance the anti-tumor immune effects of cisplatin and/or tumor infiltrating leukocytes (TIL) ex vivo. Naive tumors were harvested and TIL were cultured with IL-2 for 10-14 days, then sorted. Murine tumor cells were then cultured with cisplatin, navitoclax, and/or TIL. In the TC-1 and MOC1 models, but not in the MEER model, navitoclax modestly enhanced tumor-cell killing by TIL. Tumor cell killing was greatest with cisplatin, navitoclax, and TIL in combination. We then investigated whether navitoclax might enhance the anti-tumor activity of cisplatin and anti-PD-1 in vivo. With twice-weekly anti-PD-1 antibody alone or added to the cisplatin and/or navitoclax in the TC-1 model, no additional anti-tumor activity was noted; flow cytometry of naïve TC-1 tumors showed extremely low numbers of CD8+ T cells as a possible explanation. Similar experiments in the MOC1 model, along with mechanistic experiments to investigate resistance to navitoclax in vivo, are in progress. Conclusions: Navitoclax enhances cisplatin-induced death of human HNSCC cells in vitro and enhances the killing of murine tumor cells when cultured with TIL ex vivo. However, in multiple syngeneic mouse models, navitoclax failed to enhance anti-tumor activity of cisplatin or anti-PD-1 checkpoint blockade. Possible mechanisms of navitoclax resistance in vivo may include enhanced trafficking of immunosuppressive cells to the tumor microenvironment following secretion of senescence-associated cytokines by cisplatin-treated tumor cells. Supported by NIDCD intramural project number ZIA-DC000090. Citation Format: Youji Hong, Sreenivasulu Gunti, Yvette Robbins, Nicole C. Schmitt. Senolytic drug ABT-263 enhances cisplatin- and TIL-induced cell death in vitro but has limited in vivo activity in preclinical models of head and neck cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5830.

Modulatory Effect of Rutin on the Antitumor Activity and Genotoxicity of Cisplatin in Tumor-Bearing Mice

Purpose: Cisplatin is a cancer chemotherapeutic drug that has been extensively used in the treatment of a variety of cancers. However, the full usage of cisplatin is limited due to its treatment associated development of multiple side effects in the host. In the present study, the modulatory effect of rutin, a type of flavonoid, on the cisplatin mediated antitumor activity and allied genotoxicity in ascites Dalton’s lymphoma (DL)-bearing mice were investigated. Methods: The antitumor activity was determined by calculating the percent increase in the life span of mice, cell viability and scanning electron microscopy (SEM) of DL cells. Further, the modulatory effect of rutin on the cisplatin-induced genotoxic effects in the same DL-bearing mice was assessed by the analysis of micronuclei, chromosomal aberration and sperm abnormality. Results: The combination treatment of mice with rutin and cisplatin showed a considerable increase in the life span of the DL-bearing mice depicting better antitumor efficacy. SEM of these DL cells showed severe membrane deformities in DL cells such as fusion of cell membrane, membrane blebbing, cell shrinkage, membrane folding and loss in microvilli from the tumor cell surface which may lead to cell death. Cisplatin alone treatment caused an increase in the frequency of chromosomal aberrations, micronuclei and sperms abnormality. However, the combination treatment of DL-bearing mice with rutin and cisplatin comparatively reduced these genotoxic effects. Conclusion: The overall findings suggest that rutin enhances the cisplatin-mediated antitumor activity and cytotoxicity against DL cells and at the same time diminishes the genotoxic effects induced by cisplatin in the DL-bearing mice.

The long-lasting anti-tumor activity of cisplatin affecting the sustainable systemic immune alteration may improve distant-disease free survival of triple-negative breast cancer in patients with a substantial residual tumor following preoperative chemotherapy: A retrospective analysis with translational research.

e12631 Background: Residual disease after preoperative chemotherapy is known to be a poor prognostic factor in triple-negative breast cancer (TNBC). Perioperative use of cisplatin (CDDP) is a well-known, standard treatment for most tumors except breast cancer. In this study, we explore the long-lasting anti-tumor activity of CDDP for TNBC patients. Methods: This research was based on consecutive study of seventy-nine previously untreated stage I–III TNBC patients treated with or without CDDP-based preoperative chemotherapy from 2007 to 2018 at the Kyoto University Hospital. We calculated the residual cancer burden (RCB) using the RCB calculator. All patients were sorted according to their RCB class: the pathological complete response (pCR), and RCB class I (minimal), II (moderate) or III (extensive). Distant disease-free survival (DDFS) was analyzed using the Kaplan-Meier method. Using mass spectrometry, we measured platinum concentrations in serum and normal breast tissue removed during surgery from patients treated with any platinum agents. We examined multiplex cytokine assays from serum sequentially, comparing CDDP and non-CDDP groups. Results: Forty-seven cases were treated with CDDP, and thirty-two did not have CDDP. The pCR rate was 53.2% for the CDDP group and 21.9% without CDDP. Patients with pCR and RCB class I were all distant disease-free. There was no significant difference between each RCB class using CDDP. However, patients belonging to RCB classes II and III with CDDP showed a better prognosis than the same RCB classes without CDDP (hazard ratio = 0.12). Platinum concentrations in serum were correlated with the time from the last dose of platinum agents, but platinum was even detected in serum two years after CDDP. No significant difference was found in the platinum concentrations of serum or normal breast tissue in the pCR and non-pCR groups. We also found that there were significant cytokine expression alteration related to T-cell infiltration only in the CDDP group one year after operation. It is suggested that CDDP may even affect the systemic immune alteration one year after operation. Conclusions: Our data shows that CDDP- based chemotherapy improves DDFS in patients with a substantial residual tumor. CDDP seems to sustain anti-tumor activity for a number of years and interaction with the systemic immune alteration.

Cross-linking of the DNA repair protein O6-alkylguanine DNA alkyltransferase to DNA in the presence of cisplatin

1,1,2,2-cis-diamminedichloroplatinum (II) (cisplatin) is a chemotherapeutic agent widely used in the clinic to treat various cancers. The antitumor activity of cisplatin is generally attributed to its ability to form intrastrand and interstrand DNA-DNA cross-links via sequential platination of two nucleophilic sites within the DNA duplex. However, cisplatin also induces DNA- protein lesions (DPCs) that may contribute to its biological effects due to their ability to block DNA replication and transcription. We previously reported that over 250 nuclear proteins including high mobility group proteins, histone proteins, and elongation factors formed DPCs in human HT1080 cells treated with cisplatin (Ming et al. Chem. Res. Toxicol. 2017, 30, 980–995). Interestingly, cisplatin-induced DNA-protein conjugates were reversed upon heating, by an unknown mechanism. In the present work, DNA repair protein O6-alkylguanine DNA alkyltransferase (AGT) was used as a model to investigate the molecular details of cisplatin-mediated DNA-protein cross-linking and to establish the mechanism of their reversal. We found that AGT is readily cross-linked to DNA in the presence of cisplatin. HPLC-ESI+-MS/MS sequencing of tryptic peptides originating from dG-Pt-AGT complexes revealed that the cross-linking occurred at six sites within this protein including Glu110, Lys125, Cys145, His146, Arg147, and Cys150. Cisplatin-induced Lys-Gua cross-links (1,1-cis-diammine-2-(5-amino-5-carboxypentyl)amino-2-(2'-deoxyguanosine-7-yl)-platinum(II) (dG-Pt-Lys) were detected by HPLC-ESI+-MS/MS of total digests of modified protein in comparison with the corresponding authentic standard. Upon heating, dG-Pt-AGT complexes were subject to platination migration from protein to DNA, forming cis-[Pt(NH3)2{d(GpG)}] cross-links which were detected by HPLC-ESI+-MS/MS. Our results provide a new insight into the mechanism of cisplatin-mediated DNA-protein cross-linking and their dynamic equilibrium with the corresponding DNA-DNA lesions.

The antitumor activity of Arthrospira platensis and/or cisplatin in a murine model of Ehrlich ascites carcinoma with hematinic and hepato-renal protective action

• Spirulina (SP) has antitumor action in Ehrlich ascites carcinoma (EAC) bearing mice. • SP potentiated cisplatin (CDDP) antitumor activity in EAC bearing mice. • SP and or CDDP adjusted peritoneal Caspase-3 and Ki-67 immunoexpression. • SP reduced CDDP induced hepato-renal damage. • SP corrected CDDP - induced hematological and bone marrow alterations. Herein two experiments were conducted. The first experiment evaluated the antitumor activity of Arthrospira platensis ( Spirulina platensis , SP) alone or in combination with cisplatin (CDDP) in Ehrlich ascites carcinoma (EAC) bearing mice. The second experiment assessed the outcomes of SP and/or CDDP administration on renal, hepatic, and bone marrow function in normal mice. The results showed that the EAC evoked a significant decrease in the mice survival rate, life span percentage, antioxidant defense system, and Caspase-3 immunoexpression but a significant increase in the viable cancer cells count, tumor and lipid peroxidation biomarkers concentrations, and Ki-67 immunoexpression. The EAC induced alterations improved to various degrees following SP and/or CDDP administration. SP minimized the oxidative hepatic and renal DNA-damaging and hematotoxic effect of CDDP. Overall, SP has a potent anticancer activity and could be used effectively as a hematinic and hepato-renal protective agent with anticancer drugs like CDDP.

New Insights in the Pathogenesis of Cisplatin-Induced Nephrotoxicity

Abstract Cisplatin (cis-diamminedichloroplatinum II) is a widely used chemotherapeutic agent. However, efficacy and clinical utility of this drug is significantly limited by severe side effects such as nephrotoxicity which develops due to renal accumulation and bio-transformation in proximal tubular epithelial cells. Cisplatin-induced nephrotoxicity can be manifested as acute kidney injury (AKI), or as different types of tubulopathies, salt wasting, loss of urinary concentrating ability, and magnesium wasting. The attenuation of cisplatin-caused AKI is currently accomplished by hydration, magnesium supplementation or mannitol-induced forced diuresis. However, mannitol treatment causes over-diuresis and consequent dehydration, indicating an urgent need for the clinical use of newly designed, safe and efficacious renoprotective drug, as an additive therapy for high dose cisplatin-treated patients. Accordingly, we emphasized current knowledge regarding molecular mechanisms responsible for cisplatin-caused nephrotoxicity and we described in detail the main clinical manifestations of cisplatin-induced renal dysfunction in order to pave the way for the design of new therapeutic approaches that can minimize detrimental effects of cisplatin in the kidneys. Having in mind that most of cisplatin-induced cytotoxic effects against renal cells are, at the same time, involved in anti-tumor activity of cisplatin, new nephroprotective therapeutic strategies have to prevent renal injury and inflammation without affecting cisplatin-induced toxicity against malignant cells.

Effect of the chemoprotectant tempol on anti-tumor activity of cisplatin

To investigate the effect of the chemoprotectant tempol on the anti-tumor activity of cisplatin (DDP). The cellular toxicity of tempol in human colon cancer SW480 cells and mouse colon cancer CT26 cells were evaluated using MTT and cell counting kit-8 assays. CalcuSyn software analysis was used to determine the interaction between tempol and DDP in inhibition of the cell viability. A subcutaneous homograft mouse model of colon cancer was established. The mice were randomly divided into control group, tempol group, cisplatin group and tempol + DDP treatment group with intraperitoneal injections of the indicated agents. The tumor size, body weight and lifespan of the mice were measured, and HE staining was used to analyze the cytotoxic effect of the agents on the kidney and liver. Immunohistochemistry and Western blotting were performed to detect the expression of Bax and Bcl2 in the tumor tissue, and TUNEL staining was used to analyze the tumor cell apoptosis. The level of reactive oxygen species (ROS) in the tumor tissue was determined using flow cytometry. Tempol showed inhibitory effects on the viability of SW480 and CT26 cells. CalcuSyn software analysis showed that tempol had a synergistic anti-tumor effect with DDP (CI &lt; 1). In the homograft mouse model, tempol treatment alone did not produce obvious anti-tumor effect. HE staining showed that the combined use of tempol and DDP alleviated DDP-induced fibrogenesis in the kidneys, but tempol also reduced the anti-tumor activity of DDP. Compared with the mice treated with DDP alone, the mice treated with both tempol and DDP had a significantly larger tumor size (P &lt; 0.01) and a shorter lifespan (P &lt; 0.05). Tempol significantly reversed DDP-induced expression of Bax and Bcl2 in the tumor tissue and tumor cell apoptosis (P &lt; 0.001), and obviously reduced the elevation of ROS level in the tumor tissue induced by DDP treatment (P &lt; 0.05). Tempol can attenuate the anti-tumor effect of DDP while reducing the side effects of DDP. Caution must be taken and the risks and benefits should be carefully weighed when considering the use of tempol as an anti-oxidant to reduce the toxicities of DDP.