Cisplatin Combination Therapy Research Articles

Prediction Model for Severe Thrombocytopenia Induced by Gemcitabine Plus Cisplatin Combination Therapy in Patients with Urothelial Cancer.

Chemotherapy-induced thrombocytopenia is often a use-limiting adverse reaction to gemcitabine and cisplatin (GC) combination chemotherapy, reducing therapeutic intensity, and, in some cases, requiring platelet transfusion. A retrospective cohort study was conducted on patients with urothelial cancer at the initiation of GC combination therapy and the objective was to develop a prediction model for the incidence of severe thrombocytopenia using machine learning. We performed receiver operating characteristic analysis to determine the cut-off values of the associated factors. Multivariate analyses were conducted to identify risk factors associated with the occurrence of severe thrombocytopenia. The prediction model was constructed from an ensemble model and gradient-boosted decision trees to estimate the risk of an outcome using the risk factors associated with the occurrence of severe thrombocytopenia. Of 186 patients included in this study, 46 (25%) experienced severe thrombocytopenia induced by GC therapy. Multivariate analyses revealed that platelet count ≤ 21.4 (×104/µL) [odds ratio 7.19, p<0.01], hemoglobin ≤ 12.1 (g/dL) [odds ratio 2.41, p=0.03], lymphocyte count ≤ 1.458 (×103/µL) [odds ratio 2.47, p=0.02], and dose of gemcitabine ≥ 775.245 (mg/m2) [odds ratio 4.00, p<0.01] were risk factors of severe thrombocytopenia. The performance of the prediction model using these associated factors was high (area under the curve 0.76, accuracy 0.82, precision 0.68, recall 0.50, and F-measure 0.58). Platelet count, hemoglobin level, lymphocyte count, and gemcitabine dose contributed to the development of a novel prediction model to identify the incidence of GC-induced severe thrombocytopenia.

Long noncoding RNA TUG1 promotes cisplatin resistance in ovarian cancer via upregulation of DNA polymerase eta.

Chemoresistance is a major cause of high mortality and poor survival in patients with ovarian cancer (OVCA). Understanding the mechanisms of chemoresistance is urgently required to develop effective therapeutic approaches to OVCA. Here, we show that expression of the long noncoding RNA, taurine upregulated gene 1 (TUG1), is markedly upregulated in samples from OVCA patients who developed resistance to primary platinum-based therapy. Depletion of TUG1 increased sensitivity to cisplatin in the OVCA cell lines, SKOV3 and KURAMOCHI. Combination therapy of cisplatin with antisense oligonucleotides targeting TUG1 coupled with a drug delivery system effectively relieved the tumor burden in xenograft mouse models. Mechanistically, TUG1 acts as a competing endogenous RNA by downregulating miR-4687-3p and miR-6088, both of which target DNA polymerase eta (POLH), an enzyme required for translesion DNA synthesis. Overexpression of POLH reversed the effect of TUG1 depletion on cisplatin-induced cytotoxicity. Our data suggest that TUG1 upregulation allows OVCA to tolerate DNA damage via upregulation of POLH; this provides a strong rationale for targeting TUG1 to overcome cisplatin resistance in OVCA.

Molecular mechanism of Spatholobi Caulis treatment for cholangiocarcinoma based on network pharmacology, molecular docking, and molecular dynamics simulation.

Cholangiocarcinoma (CCA) is a type of malignant tumor originating from the intrahepatic, periportal, or distal biliary system. The treatment means for CCA is limited, and its prognosis is poor. Spatholobi Caulis (SC) is reported to have effects on anti-inflammatory and anti-tumor, but its role in CCA is unclear. First, the potential molecular mechanism of SC for CCA treatment was explored based on network pharmacology, and the core targets were verified by molecular docking and molecular dynamics simulation. Then, we explored the inhibitory effect of SC on the malignant biological behavior of CCA in vitro and in vivo and also explored the related signaling pathways. The effect of combination therapy of SC and cisplatin (DDP) in CCA was also explored. Finally, we conducted a network pharmacological study and simple experimental verification on luteolin, one of the main components of SC. Network pharmacology analysis showed that the core targets of SC on CCA were AKT1, CASP3, MYC, TP53, and VEGFA. Molecular docking and molecular dynamics simulation indicated a good combination between the core target protein and the corresponding active ingredients. In vitro, SC inhibited proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) of CCA cells. In vivo experiments, the results were consistent with in vitro experiments, and there was no significant hepatorenal toxicity of SC at our dosage. Based on KEGG enrichment analysis, we found PI3K/AKT signaling pathway might be the main signaling pathway of SC action on CCA by using AKT agonist SC79. To explore whether SC was related to the chemotherapy sensitivity of CCA, we found that SC combined with DDP could more effectively inhibit the progression of cholangiocarcinoma. Finally, we found luteolin may inhibit the proliferation and invasion of CCA cells. Our study demonstrates for the first time that SC inhibits the progression of CCA by suppressing EMT through the PI3K-AKT signaling pathway, and SC could enhance the effectiveness of cisplatin therapy for CCA.

Selective fluorescence turn-on detection of combination cisplatin-etoposide chemotherapy based on N-CDs/GSH-CuNCs nanoprobe.

Cisplatin (CIS) and etoposide (ETP) combination therapy is highly effective for treating various cancers. However, the potential for pharmacokinetic interactions between these drugs necessitates selective sensing methods to quantitate both CIS and ETP levels in patient's plasma. This work develops a dual fluorescence probe strategy using glutathione-capped copper nanoclusters (GSH-CuNCs) and nitrogen-doped carbon dots (N-CDs) for the simultaneous analysis of CIS and ETP. The fluorescence signal of GSH-CuNCs at 615 nm increased linearly with CIS concentration while the N-CD emission at 480 nm remained unaffected. Conversely, the N-CD fluorescence was selectively enhanced by ETP with no interference with the CuNC fluorescence. Extensive materials characterization including UV-vis, fluorescence spectroscopy, XRD, and TEM confirmed the synthesis of the nanoprobes. The sensor showed high sensitivity with limits of detection of 6.95 ng mL-1 for CIS and 7.63 ng mL-1 for ETP along with excellent selectivity against potential interferences in rabbit plasma. Method feasibility was demonstrated with application to real rabbit plasma samples. The method was further applied to estimate the pharmacokinetic parameters of CIS before and after ETP coadministration. The dual nanoprobe sensing strategy enables rapid and selective quantitation of CIS and ETP levels to facilitate therapeutic drug monitoring and optimization of combination chemotherapy regimens.

Endometrial cancer PDX-derived organoids (PDXOs) and PDXs with FGFR2c isoform expression are sensitive to FGFR inhibition

Endometrial cancer (EC) patients with metastatic/recurrent disease have limited treatment options and poor survival outcomes. Recently, we discovered the FGFR2c splice isoform is associated with poor prognosis in EC patients. Here we report the establishment of 16 EC patient-derived xenografts (PDX)-derived organoids (PDXOs) with or without FGFR2c expression. In vitro treatment of 5 EC PDXOs with BGJ398 showed significant cell death in 3 models with FGFR2c expression. PDXs with high/moderate FGFR2c expression showed significant tumour growth inhibition (TGI) following 21-day treatment with FGFR inhibitors (BGJ398 or pemigatinib) and significantly prolonged survival in 4/5 models. Pemigatinib + cisplatin combination therapy (n = 5) resulted in significant TGI and prolonged survival in one of two p53abn PDXs. All five models treated with cisplatin alone showed de novo resistance and no survival benefit. Seven-day treatment with BGJ398 revealed a significant reduction in angiogenesis and CD206 + M2 macrophages. These data collectively support the evaluation of FGFR inhibitors in a clinical trial.

Abrogation of ATR function preferentially augments cisplatin-induced cytotoxicity in PTEN-deficient breast cancer cells

Targeting replication stress response is currently emerging as new therapeutic strategy for cancer treatment, based on monotherapy and combination approaches. As a key sensor in response to DNA damage, ataxia telangiectasia and rad3-related (ATR) kinase has become a potential therapeutic target as tumor cells are to rely heavily on ATR for survival. The tumor suppressor phosphatase and tensin homolog (PTEN) plays a crucial role in maintaining chromosome integrity. Although ATR inhibition was recently confirmed to show a synergistic inhibitory effect in PTEN-deficient triple-negative breast cancer cells, the molecular mechanism needs to be further elucidated. Additionally, whether the PTEN-deficient breast cancer cells are more preferentially sensitized than PTEN-wild type breast cancer cells to cisplatin plus ATR inhibitor remains unanswered. We demonstrate PTEN dysfunction promotes the killing effect of ATR blockade through the use of RNA interference for PTEN and a highly selective ATR inhibitor VE-821, and certify that VE-821 (1.0 μmol/L) aggravates cytotoxicity of cisplatin on breast cancer cells, especially PTEN-null MDA-MB-468 cells which show more chemoresistance than PTEN-expressing MDA-MB-231 cells. The co-treatment with VE-821 and cisplatin significantly reduced cell viability and proliferative capacity compared with cisplatin mono-treatment (P < 0.05). The increased cytotoxic activity is tied to the enhanced poly (ADP-ribose) polymerase (PARP) cleavage and consequently cell death due to the decrease in phosphorylation levels of checkpoint kinases 1 and 2 (CHK1/2), the reduction of radiation sensitive 51 (RAD51) foci and the increase in phosphorylation of the histone variant H2AX (γ-H2AX) foci (P < 0.05) as well. Together, these findings suggest combination therapy of ATR inhibitor and cisplatin may offer a potential therapeutic strategy for breast tumors.

Synergistic antitumor efficacy of gemcitabine and cisplatin to induce ferroptosis in pancreatic ductal adenocarcinoma via Sp1-SAT1-polyamine metabolism pathway.

The combination of cisplatin and gemcitabine-based chemotherapy has been recommended as a preferred regimen for pancreatic ductal adenocarcinoma (PDAC) patients with germline-based mutations. However, the underlying mechanism remains poorly elucidated. Therefore, our study aimed to explore the mechanistic basis of the cell-killing activity of gemcitabine plus cisplatin and identify potential therapeutic targets. First, we explored the synergistic cytotoxic effects of gemcitabine and cisplatin on PDAC through in vitro and in vivo experiments. Then, we investigated ferroptosis-related biomarkers, to assess the impact of the combination therapy on ferroptosis. Using bioinformatics methods, we identified SAT1 as a potential key mediator of ferroptosis induced by gemcitabine and cisplatin. We tested the polyamine levels in PDAC cells by LC-MS after overexpressed or knocked down SAT1, and explored the role of polyamines in ferroptosis using exogenous supplementation. Finally, we explored the regulatory effect of Sp1 on SAT1 through ChIP-qPCR and dual-luciferase reporter assay. Gemcitabine plus cisplatin enhanced cell death and induced ferroptosis in PDAC. This combination upregulated SAT1 transcription by inhibiting Sp1. SAT1 activation promoted the catabolism of spermine and spermidine, leading to iron accumulation and lipid peroxide generation, ultimately resulting in ferroptosis. In summary, our findings suggested the gemcitabine and cisplatin combination therapy induced ferroptosis in a GSH-independent manner in PDAC. The combined treatment inhibited Sp1 and upregulated SAT1 transcription, leading to the breakdown of spermine and spermidine. Therefore, targeting SAT1-induced polyamine metabolism may represent a promising therapeutic strategy for PDAC.

Combination therapy with anti-programmed cell death 1 antibody plus angiokinase inhibitor exerts synergistic antitumor effect against malignant mesothelioma via tumor microenvironment modulation

Malignant pleural mesothelioma (MPM) is an asbestos-related fatal malignant neoplasm. Although there has been no reliable chemotherapeutic regimen other than combination therapy of cisplatin and pemetrexed for two decades, combination of ipilimumab plus nivolumab brought about a better outcome in patients with MPM. Thus, cancer immunotherapy using immune checkpoint inhibitor (ICI) is expected to play a central role in the treatment of MPM. To maximize the antitumor effect of ICI, we evaluated whether nintedanib, an antiangiogenic agent, could augment the antitumor effect of anti-programmed cell death 1 (PD-1) antibody (Ab). Although nintedanib could not inhibit the proliferation of mesothelioma cells in vitro, it significantly suppressed the growth of mesothelioma allografts in mice. Moreover, combination therapy with anti-PD-1 Ab plus nintedanib reduced tumor burden more dramatically compared with nintedanib monotherapy via inducing remarkable necrosis in MPM allografts. Nintedanib did not promote the infiltration of CD8+ T cells within the tumor when used alone or in combination with anti-PD-1 Ab but it independently decreased the infiltration of tumor-associated macrophages (TAMs). Moreover, immunohistochemical analysis and ex vivo study using bone marrow-derived macrophages (BMDMs) showed that nintedanib could polarize TAMs from M2 to M1 phenotype. These results indicated that nintedanib had a potential to suppress protumor activity of TAMs both numerically and functionally. On the other hand, ex vivo study revealed that nintedanib upregulated the expression of PD-1 and PD-ligand 1 (PD-L1) in BMDMs and mesothelioma cells, respectively, and exhibited the impairment of phagocytic activity of BMDMs against mesothelioma cells. Co-administration of anti-PD-1 Ab may reactivate phagocytic activity of BMDMs by disrupting nintedanib-induced immunosuppressive signal via binding between PD-1 on BMDMs and PD-L1 on mesothelioma cells. Collectively, combination therapy of anti-PD-1 Ab plus nintedanib enhances the antitumor activity compared with respective monotherapy and can become a novel therapeutic option for patients with MPM.

Combination therapy of cisplatin and resveratrol to induce cellular aging in gastric cancer cells: Focusing on oxidative stress, and cell cycle arrest.

Background: As a medical dilemma, gastric cancer will have 7.3million new cases in 2040. Despite the disease's high economic and global burden, conventional chemotherapy regimens containing cisplatin have insufficient effectiveness and act non-specifically, leading to several adverse drug reactions To address these issues, the biological efficacy of the cisplatin-resveratrol combination was tested. Methods: To find IC50, gastric adenocarcinoma cells (AGS) were exposed to different concentrations of resveratrol and cisplatin. Anti-cancer and anti-metastatic effects of 100M resveratrol with concentrations of cisplatin (25, 50, and 100g/ml) were studied by assessing ß-galactosidase and telomerase activities, senescence and migration gene expression, reactive oxygen species (ROS) level, and cell cycle arrest. Results: Co-administration of cisplatin and resveratrol increased ß-galactosidase activity, ROS level as a key marker of oxidative stress, p53, p38, p16, p21, and MMP-2 gene expression, and induced G0/G1 cell cycle arrest. Additionally, telomerase activity, pro-inflammatory gene expression, and cell invasion were suppressed. The best results were achieved with 100g/ml cisplatin co-administered with resveratrol. Conclusion: The current study proved the synergistic effect of the cisplatin-resveratrol combination on suppressing metastasis and inducing apoptosis and cell senescence through targeting P38/P53 and P16/P21 pathways. Such promising results warrant translation to animal models and the clinic. This may lead to cost-effective, available, and accessible treatment regimens with targeted action and the fewest ADRs.

ANTI-PROLIFERATION EFFECT AND INDUCTION PPARG EXPRESSION OF HUMAN CERVICAL CANCER CELLS BY COMBINATION OF GRAPE LEAF ETHANOL EXTRACT AND CISPLATIN

This study aims to analyze the combination of grape leaf ethanol extract ( Vitis vinifera ) and cisplatin to increase peroxisome proliferator-activated receptor gamma (PPARγ) expression and inhibit HeLa cell proliferation in vitro. This research described a new combination therapy method. This research included the cytotoxicity test, proliferation test with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) Assay, PPARγ expression using immunofluorescence method. The anticancer effects of grape leaf extract (2.5, 5, and 10 mg/mL) were studied through grape leaf phytochemical assays. In this study, the expression of PPARγ increased significantly in grape leaf extract 10 mg/mL + cisplatin. The combination therapy of grape leaf ethanol extract ( Vitis vinifera ) and cisplatin proved to be more effective than single therapy (p &lt; 0.05). Cisplatin with polyphenolic active compounds (phenolics) can inhibit the proliferation of cervical cancer cells. Combination therapy of cisplatin and grape leaf extract inhibited the survival of HeLa cells. Keywords: Grape Leaves, Cell Proliferation, Ethanol Extract, PPARγ, Phenolic Test DOI： https://doi.org/10.35741/issn.0258-2724.58.3.13

Risk factors associated with cisplatin-induced ototoxicity in Japanese patients with solid tumors.

Cisplatin, a first-generation platinum agent, is used for managing various cancers and is associated with dose-dependent side effects of hearing impairment and tinnitus. However, the safety of high-dose cisplatin in hearing impairment, has not been fully investigated in Japan. We performed pure-tone threshold audiometry before and every 3-4 weeks after chemotherapy for patients receiving cisplatin-containing chemotherapy between April 2015 and October 2017 at Kobe Minimally Invasive Cancer Center. Hearing impairment was evaluated prospectively using the National Cancer Institute Common Terminology Criteria for Adverse Events version 4.0. We enrolled 100 patients and analyzed 96 patients for whom post-chemotherapy audiometry could be performed. The median patient age was 65 years, and most patients were male (75). The cancer types were as follows: esophageal, 36; head and neck, 35; lung, 23; and gastric, 2. Cisplatin monotherapy and combination therapy were administered to 33 and 63 patients, respectively. A single cisplatin dose was 60-100 mg/m2 ; the median number of doses and total dose were 3 and 240 mg/m2 , respectively. Additionally, 78 and 18 patients were treated with concurrent chemoradiotherapy and chemotherapy alone, respectively. Twenty-seven patients had grade 2 or higher hearing impairment. Furthermore, the prevalence was significantly higher in patients receiving a total dose of ≥300 mg/m2 . Twenty and 32 patients were aware of deafness and tinnitus, respectively. No patient discontinued treatment owing to hearing impairment. The total cisplatin dose was considered related to post-treatment hearing impairment frequency in Japanese patients. However, routine audiometric monitoring is recommended during high-dose cisplatin-based chemotherapy.

Inhibition of TIGAR Increases Exogenous p53 and Cisplatin Combination Sensitivity in Lung Cancer Cells by Regulating Glycolytic Flux.

The metabolism and apoptosis of tumor cells are important factors that increase their sensitivity to chemotherapeutic drugs. p53 and cisplatin not only induce tumor cell apoptosis, but also regulate the tumor cell metabolism. The TP53-induced glycolysis and apoptosis regulator (TIGAR) can inhibit glycolysis and promote more glucose metabolism in the pentose phosphate pathway. We speculate that the regulation of the TIGAR by the combination therapy of p53 and cisplatin plays an important role in increasing the sensitivity of tumor cells to cisplatin. In this study, we found that the combined treatment of p53 and cisplatin was able to inhibit the mitochondrial function, promote mitochondrial pathway-induced apoptosis, and increase the sensitivity. Furthermore, the expression of the TIGAR was inhibited after a combined p53 and cisplatin treatment, the features of the TIGAR that regulate the pentose phosphate pathway were inhibited, the glucose flux shifted towards glycolysis, and the localization of the complex of the TIGAR and Hexokinase 2 (HK2) on the mitochondria was also reduced. Therefore, the combined treatment of p53 and cisplatin may modulate a glycolytic flux through the TIGAR, altering the cellular metabolic patterns while increasing apoptosis. Taken together, our findings reveal that the TIGAR may serve as a potential therapeutic target to increase the sensitivity of lung cancer A549 cells to cisplatin.

Beta-Caryophyllene Enhances the Anti-Tumor Activity of Cisplatin in Lung Cancer Cell Lines through Regulating Cell Cycle and Apoptosis Signaling Molecules

Beta-Caryophyllene (BCP), a natural bicyclic sesquiterpenes, is an abundant biomolecule in red pepper and other plants. Recently, it was reported to reduce the growth and the proliferation as well as enhance the apoptosis in numerous cancer cells, including colorectal, ovarian, bladder cancer and lung cancer. On the other hand, the combination therapy of cisplatin (CDDP) with other phytochemical compounds has synergistically enhanced the killing effect of CDDP on several types of cancer. In the current model, we have tested the role of BCP in enhancing the anti-tumor activity of CDDP on lung cancer cell lines. The results showed that BCP is not toxic at moderate doses and it can prevent lung cancer progression in doses above 75 µM. However, when being combined with CDDP, BCP improved the former chemotherapeutic function through regulating cell cycle, apoptosis and EMT signaling molecules. Gene and protein expression analysis showed that the combined treatment of CDDP and BCP significantly upregulated the level of the cyclin-dependent kinase inhibitor, CDKN1A, and the inhibitor of the apoptosis, BCL-xl2. In addition, the combination treatment reduced the protein level of the apoptosis regulator, BCL-2. Moreover, BCP appears to prohibit the EMT process that is associated with CDDP chemotherapy since the combination treatment induced a significant increase in the level of the epithelial cell marker E-cad that was reduced in CDDP-treated cells. In agreement with that, the combined treatment managed to modulate the effect of CDDP on the mesenchymal transcription factor ZEB-2. Additionally, molecular docking has been conducted to check the virtual interaction of BCP with these and other signaling molecules, but only cyclin-dependent kinase CDK6 was found to virtually bind with BCP, and at four sites with higher and stable biding energy (-7.8). Together, these data indicate that BCP enhances CDDP chemotherapeutic function through regulating the cell cycle, the apoptosis and EMT signaling molecules.

Glutathione-sensitive nanoparticles enhance the combined therapeutic effect of checkpoint kinase 1 inhibitor and cisplatin in prostate cancer.

Prostate cancer (PCa) is the second most common malignant tumor among males. Traditional treatments for PCa, which include surgery and endocrine therapy, have shown limited success, and more effective therapies are needed. Cisplatin (DDP) is an approved chemotherapeutic drug that causes DNA damage in cancer, whereas AZD7762, an inhibitor of CHK1, can significantly inhibit DNA repair. The effective therapeutic combination of cisplatin and the DNA damage response inhibitor AZD7762 has been considered to be a potential solution to the resistance to cisplatin and the adverse reactions that occur in many cancers. However, the co-transmission of cisplatin and AZD7762 and the unsatisfactory tumor-targeting efficacy of this therapy remain problems to be solved. Here, we confirmed the combined therapeutic efficacy of cisplatin and AZD7762 in PCa. Furthermore, we show that the glutathione-targeted Cys8E nanoparticles we synthesized, which have high drug-loading capacity, remarkable stability, and satisfactory release efficiency, enhanced the therapeutic efficacy of this treatment and reduced the required dosages of these drugs both in vitro and in vivo. Overall, we propose combination therapy of cisplatin and AZD7762 for PCa and facilitate it using Cys8E nanoparticles, which allow for better drug loading release, higher release efficiency, and more accurate tumor-targeting efficacy.

Activation of cGAS-STING Signal to Inhibit the Proliferation of Bladder Cancer: The Immune Effect of Cisplatin.

Cisplatin is commonly used in neoadjuvant, adjuvant, and systemic therapy for advanced bladder cancer, but its immune-related mechanism is still unclear. Exploration of the immune effects of cisplatin in bladder cancer would complement the comprehensive mechanism of cisplatin and provide the basis for combination therapy of cisplatin and immunotherapy in bladder cancer. We confirmed the immune effects of cisplatin on T24 and TCCSUP bladder cancer cell lines in vitro and explored the important function of these immune effects in the bladder cancer microenvironment in a mice tumor model. We found cisplatin induced immune response in bladder cancer by RNA sequencing and validated that cGAS-STING signal was deeply involved in this response. Cisplatin induced cGAS-STING signal inhibited the proliferation of bladder cancer and increased the infiltration percentages of CD8+ T cells and dendritic cells in a transplantation mice tumor model. Accumulation of dsDNA and the release of chromatin bound cGAS are important to activate downstream STING. Our findings indicated a cisplatin-related immune effect in bladder cancer, and cisplatin combined with immunotherapy might have a synergistic effect for bladder cancer therapy.

Pentagalloyl Glucose and Cisplatin Combination Treatment Exhibits a Synergistic Anticancer Effect in 2D and 3D Models of Head and Neck Carcinoma.

Although cisplatin is a first-line chemotherapy drug for head and neck squamous cell carcinoma (HNSCC), its therapeutic efficacy is limited owing to serious side effects and acquired drug resistance. This study determined whether combining pentagalloyl glucose (PGG) and cisplatin enhanced their anti-tumor activities on HNSCC cell lines. We investigated the anticancer effect of PGG combined with cisplatin in 2D and 3D multicellular spheroid cell culture. The results revealed that PGG combined with cisplatin inhibited cell viability and produced synergistic effects. PGG potentiates the anticancer effect of cisplatin by promoting apoptosis and inhibiting cell migration. The western blot and molecular docking analysis revealed that the synergistic effect of the combination treatment may be related to the PGG-mediated reduced expression of phosphorylated STAT3 and phosphorylated Akt. Furthermore, we found that the combined treatment of PGG and cisplatin’s effect on 3D multicellular spheroid size was more potent than the monotherapies. Our findings indicated that the combination therapy of PGG and cisplatin synergistically inhibited HNSCC cancer cell viability and induced apoptosis in 2D and 3D models. The present results suggested that PGG may be a promising adjunct drug used with cisplatin for a practical therapeutic approach to head and neck cancer.

Abstract 3971: Genome-wide CRISPR/Cas9 screening reveals ATR as a therapeutic target that overcomes osteosarcoma chemoresistance

Abstract Osteosarcoma (OS) is the most common bone cancer in pediatric patients. Therapeutic target identification in OS has been extremely challenging due to the high degree of heterogeneity in its genetic profile and lack of specific oncogenic driver genes. Despite extensive research efforts, the treatment and survival outcomes for OS patients have stagnated over the past 30 years. OS remains a lethal cancer due to metastasis and development of resistance to current chemotherapies. Study of chemo-resistance mechanisms and identification of novel targets that can be used in combination therapy are therefore critical to improve OS treatment. The combination of gene essentiality concept and clustered, regularly interspaced, short palindromic repeats-associated nuclease Cas9 (CRISPR/Cas9) functional knockout screen is an ideal new strategy to address the genetic complexity and drug-resistance in OS. A gene is considered essential if it is critical for reproductive success in an organism under specified condition. The recent introduction of genome editing using the CRISPR/Cas9 system with pooled library of guided RNAs (gRNAs) makes it feasible to systematically identify the genes required for the proliferation. By comparing the fold change of gRNA abundance in the surviving population of cells relative to the initial population, the essential genes under different settings can be identified.As a novel therapeutic approach for identifying combination therapies for OS, we conducted genome-wide (GW) CRISPR/Cas9 screen in SaOS2 OS cell lines parallel with RNA-sequencing in different conditions (control, Cisplatin, Doxorubicin), followed by gene essentiality score calculation. Cisplatin (CIS) and Doxorubicin (DOX) combination is among those commonly used as first-line therapies for OS treatment. The objective of our studies is to bring forth new perspectives in target identification and chemo-resistance study for OS. The gene targets and pathways that become more essential for OS cell proliferation in the presence of chemo drugs were revealed. Drugs specific for some of these target could then be added to the established CIS or DOX regimen to overcome existing drug resistance. On the other hand, the genes that become less essential after treatment could provide additional chemo-resistant mechanisms. Multiple gene targets were identified in the screen. Among these, we’ve successfully identified and validated Berzosertib, an ataxia telangiectasia and Rad3-related protein kinase inhibitor (ATRi), as a synergistic lethality partner to Cisplatin in vitro for OS treatment. Efficacy and safety measurement of Berzosertib and Cisplatin combination therapy in an OS xenograft mouse model and in several OS patient-derived xenograft models is in progress. Citation Format: Shan Tang, Karen E. Pollok, Pankita H. Pandya, Ryan D. Roberts, Xue Wu, Lang Li. Genome-wide CRISPR/Cas9 screening reveals ATR as a therapeutic target that overcomes osteosarcoma chemoresistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3971.

Melatonin Sensitizes OVCAR-3 Cells to Cisplatin through Suppression of PI3K/Akt Pathway.

This study examined the effect of melatonin on oxidative stress, expression of pro-apoptotic protein, anti-apoptotic proteins, and the activity of the PI3K/Akt signaling pathway in the human ovarian cancer cell line (OVCAR3). OVCAR3 cells were treated with cisplatin, melatonin, cisplatin + melatonin, and siRNA Akt. Reactive oxygen species levels were assessed. The expression of the proteins was determined by Western blot. Melatonin administration significantly increased intracellular ROS generation, the cleavage of caspase 3 and decreased phosphorylation of Akt. Combination therapy of cisplatin and melatonin increases apoptosis in the OVCAR-3 cells by inhibiting of PI3K/Akt signaling pathway and exacerbating oxidative stress.

Modified FOLFIRINOX as a Second-Line Treatment for Patients with Gemcitabine-Failed Advanced Biliary Tract Cancer: A Prospective Multicenter Phase II Study

Simple SummaryBiliary tract cancer is a malignant tumor of the biliary tract and gallbladder. Most patients are diagnosed at an advanced stage, and the basis of treatment is combination chemotherapy. However, the survival outcomes for biliary tract cancer, especially for patients who have failed frontline treatment, are poor. Accordingly, there have been various studies on effective subsequent treatments, and this study is one of those efforts. Through this study, we attempted to demonstrate the efficacy of enhanced chemotherapy in relapsed or refractory biliary tract cancer.Background: After the publication of the ABC-02 trial, gemcitabine and cisplatin combination therapy (GP) became the standard first-line treatment for advanced biliary tract cancer (BTC). Despite GP therapy, most patients suffer from disease progression. The ABC-06 trial recommended FOLFOX as a second-line treatment, but its efficacy was modest. In this phase II study, we looked at the efficacy and safety of a second-line modified dose of FOLFIRINOX (mFOLFIRINOX) for patients who had failed first-line gemcitabine-based treatment. Methods: From January 2020 to January 2021, 34 patients with advanced BTC who failed first-line gemcitabine-based chemotherapy were enrolled. We evaluated the clinical efficacy and safety outcomes of mFOLFIRINOX. Results: With a median follow-up duration of 13.4 months, the median progression-free survival and overall survival was 2.8 months (95% confidence interval (CI): 1.6–4.0 months) and 6.2 months (95% CI: 5.0–7.4 months), respectively. The objective response rate was 14.7% with no complete response. The disease control rate was 61.7%, with a disease control duration of 4.2 months. Due to the rapid progression of the disease, approximately half of all patients received less than three cycles of treatment. The most common type of adverse event (AEs) was hematopoietic AEs. The incidence of non-hematopoietic AEs was relatively low. Conclusions: The efficacy of mFOLFIRINOX as a second-line treatment in advanced BTC patients after the failure of gemcitabine-based first-line treatment was replicated, albeit with slightly shorter survival results compared to previous studies. Long-term administration of mFOLFIRINOX with toxicity management might offer a survival benefit.

Forchlorfenuron and Novel Analogs Cause Cytotoxic Effects in Untreated and Cisplatin-Resistant Malignant Mesothelioma-Derived Cells.

Malignant mesothelioma (MM) is a currently incurable, aggressive cancer derived from mesothelial cells, most often resulting from asbestos exposure. The current first-line treatment in unresectable MM is cisplatin/pemetrexed, which shows very little long-term effectiveness, necessitating research for novel therapeutic interventions. The existing chemotherapies often act on the cytoskeleton, including actin filaments and microtubules, but recent advances indicate the ‘fourth’ form consisting of the family of septins, representing a novel target. The septin inhibitor forchlorfenuron (FCF) and FCF analogs inhibit MM cell growth in vitro, but at concentrations which are too high for clinical applications. Based on the reported requirement of the chloride group in the 2-position of the pyridine ring of FCF for MM cell growth inhibition and cytotoxicity, we systematically investigated the importance (cell growth-inhibiting capacity) of the halogen atoms fluorine, chlorine, bromine and iodine in the 2- or 3-position of the pyridine ring. The MM cell lines ZL55, MSTO-211H, and SPC212, and—as a control—immortalized Met-5A mesothelial cells were used. The potency of the various halogen substitutions in FCF was mostly correlated with the atom size (covalent radius); the small fluoride analogs showed the least effect, while the largest one (iodide) most strongly decreased the MTT signals, in particular in MM cells derived from epithelioid MM. In the latter, the strongest effects in vitro were exerted by the 2-iodo and, unexpectedly, the 2-trifluoromethyl (2-CF3) FCF analogs, which were further tested in vivo in mice. However, FCF-2-I and, more strongly, FCF-2-CF3 caused rapidly occurring strong symptoms of systemic toxicity at doses lower than those previously obtained with FCF. Thus, we investigated the effectiveness of FCF (and selected analogs) in vitro in MM cells which were first exposed to cisplatin. The slowly appearing population of cisplatin-resistant cells was still susceptible to the growth-inhibiting/cytotoxic effect of FCF and its analogs, indicating that cisplatin and FCF target non-converging pathways in MM cells. Thus, a combination therapy of cisplatin and FCF (analogs) might represent a new avenue for the treatment of repopulating chemo-resistant MM cells in this currently untreatable cancer.