Cisplatin-resistant Cells Research Articles

Capsaicin Exerts Antitumor Activity in Mesothelioma Cells.

Mesothelioma is an aggressive cancer with limited treatment options. Mesothelioma therapy often involves a multimodal approach including surgery, radiotherapy and chemotherapy. However, the prognosis for patients remains poor. Difficult diagnosis, late symptoms when the tumor is in an advanced stage and the onset of chemotherapy resistance make mesothelioma difficult to treat. For this reason, it is essential to discover new pharmacological approaches. Capsaicin (CAPS) is the active compound of chili peppers. Based on CAPS's anticancer properties on various tumor lines and its chemo-sensitizing action on resistant cells, in this study, we evaluated the effects of CAPS on mesothelioma cells to assess its potential use in mesothelioma therapy. To evaluate antiproliferative effects of CAPS, we performed MTS assays on various mesothelioma cells, representative of all major mesothelioma subtypes. Transwell migration and wound-healing assays were used to examine the effect of CAPS on mesothelioma cell migration. We also determined the effects of CAPS on oncogenic signaling pathways by assessing the levels of AKT and MAPK activation. In this study, we show that CAPS significantly reduces proliferation of both parental and cisplatin-resistant mesothelioma cells. CAPS promotes S-phase cell cycle arrest and inhibits lateral motility and migration of mesothelioma cells. Accordingly, CAPS suppresses AKT and ERK1/2 activation in MSTO-211H and NCI-H2052 cells. Our results support an antitumor effect of CAPS on cisplatin-resistant mesothelioma cells, suggesting that it may reduce resistance to cisplatin. Our results could pave the way for further studies to evaluate the use of CAPS for mesothelioma treatment.

Cyclanoline Reverses Cisplatin Resistance in Bladder Cancer Cells by Inhibiting the JAK2/STAT3 Pathway.

Cisplatin is a key therapeutic agent for bladder cancer, yet the emergence of cisplatin resistance presents a significant clinical challenge. This study aims to investigate the potential and mechanisms of cyclanoline (Cyc) in overcoming cisplatin resistance. Cisplatin-resistant T24 and BIU-87 cell models (T24/DR and BIU-87/DR) were established by increasing gradual concentration. Western Blot (WB) assessed the phosphorylation of STAT3, JAK2, and JAK3. T24/DR and BIU-87/DR cell lines were treated with selective STAT3 phosphorylation modulators, and cell viability was evaluated by CCK-8. Cells were subjected to cisplatin, Cyc, or their combination. Immunofluorescence (IHC) examined p-STAT3 expression. Protein and mRNA levels of apoptosis-related and cell cycle-related factors were measured. Changes in proliferation, invasion, migration, apoptosis, and cell cycle were monitored. In vivo, subcutaneous tumor transplantation models in nude mice were established, assessing tumor volume and weight. Changes in bladder cancer tissues were observed through HE staining, and the p-STAT3 was assessed via WB and IHC. Cisplatin-resistant cell lines were successfully established, demonstrating increased phosphorylation of STAT3, JAK2, and JAK3. Cisplatin or Cyc treatment decreased p-STAT3, inhibited invasion and migration, and induced apoptosis and cell cycle arrest in the G0/G1 phase in vitro. In vivo, tumor growth was significantly suppressed, with extensive tumor cell death. IHC and WB consistently showed a substantial downregulation of STAT3 phosphorylation. These changes were more pronounced when cisplatin and Cyc were administered in combination. Cyc reverses cisplatin resistance via JAK/STAT3 inhibition in bladder cancer, offering a potential clinical strategy to enhance cisplatin efficacy in treating bladder cancer.

NPR1 promotes cisplatin resistance by inhibiting PARL-mediated mitophagy-dependent ferroptosis in gastric cancer

Cisplatin-based chemotherapy serves as the standard of care for individuals with advanced stages of gastric cancer. Nevertheless, the emergence of chemoresistance in GC has detrimental impacts on prognosis, yet the underlying mechanisms governing this phenomenon remain elusive. Level of mitophagy and ferroptosis of GC cells were detected by fluorescence, flow cytometry, GSH, MDA, Fe2+ assays, and to explore the specific molecular mechanisms between NPR1 and cisplatin resistance by performing western blot and coimmunoprecipitation (co-IP) assays. These results indicates that NPR1 positively correlated with cisplatin-resistance and played a crucial part in conferring resistance to cisplatin in gastric cancer cells. Mechanistically, NPR1 affected levels of mitophagy and ferroptosis in human cisplatin-resistance GC cells with cisplatin treatment. Specifically, NPR1 inhibited mitophagy-dependent ferroptosis by reducing the ubiquitination-mediated degradation of PARL; moreover, NPR1 promoted PARL stabilization by disrupting the PARL–MARCH8 complex, which ultimately led to the development of chemoresistance in GC cells. Considering our findings, NPR1 appears to play an important role in chemotherapy for GC. NPR1 could potentially be used to overcome chemotherapy resistance.Graphical 1. NPR1 is highly expressed in cisplatin-resistant GC cells and promotes the cisplatin resistance.2. According to IP-MS, NPR1 inhibits mitophagy-dependent ferroptosis through its downstream protein PARL.3. NPR1 promoted PARL stabilization by disrupting the PARL–MARCH8 complex to inhibit the ubiquitination-mediated degradation of PARL.

Development of a novel treatment based on PKMYT1 inhibition for cisplatin-resistant bladder cancer with miR-424-5p-dependent cyclin E1 amplification

BackgroundChemotherapy including cisplatin is recommended for the treatment of advanced bladder cancer, but its effectiveness is limited due to the acquisition of drug resistance. Although several mechanisms of cisplatin resistance have been reported, there are still many unknowns, and treatment of cisplatin-resistant bladder cancer remains difficult. Accordingly, in this study, we aimed to identify and characterize microRNAs involved in cisplatin resistance.MethodsSmall RNA sequencing analysis was performed to search for microRNAs related to cisplatin resistance. The identified microRNAs were then characterized using gain-of-function studies, sensitivity analysis, target gene analysis, and cellular assays.ResultsWe identified miR-424-5p as a candidate microRNA that was downregulated in cisplatin-resistant strains compared with parental strains. Notably, in gain-of-function studies, miR-424-5p suppressed the proliferative ability of cisplatin-resistant bladder cancer (CDDP-R BC). Furthermore, miR-424-5p restored sensitivity to cisplatin. RNA sequence analysis revealed seven candidate genes targeted by this microRNA. Among them, cyclin E1 (CCNE1) was chosen for subsequent analyses because its expression was upregulated in cisplatin-resistant cells compared with parental cells and because recent studies have shown that CCNE1 amplification is synthetic lethal with PKMYT1 kinase inhibition. Therefore, we performed functional analysis using the PKMYT1 inhibitor RP-6306 and demonstrated that RP-6306 inhibited cell growth through suppression of mitotic entry and restored cisplatin sensitivity in CDDP-R BC.ConclusionsOverall, our findings provided insights into the development of novel therapeutic strategies for CDDP-R BC.

The Contribution of the Novel CLTC-VMP1 Fusion Gene to Autophagy Regulation and Energy Metabolism in Cisplatin-Resistant Osteosarcoma.

Osteosarcoma (OS) is a highly malignant tumor, and chemotherapy resistance is a major challenge in the treatment of this disease. This study aims to explore the role of the CLTC-VMP1 gene fusion in the mechanism of chemotherapy resistance in OS and investigate its molecular mechanisms in mediating energy metabolism reprogramming by regulating autophagy and apoptosis balance. Using single-cell transcriptome analysis, the heterogeneity of OS cells and their correlation with resistance to platinum drugs were revealed. Cisplatin-resistant cell lines were established in human OS cell lines for subsequent experiments. Based on transcriptomic analysis, the importance of VMP1 in chemotherapy resistance was confirmed. Lentiviral vectors overexpressing or interfering with VMP1 were used, and it was observed that inhibiting VMP1 could reverse cisplatin resistance, promote cell apoptosis, and inhibit autophagy, as well as mitochondrial respiration and glycolysis. Furthermore, the presence of CLTC-VMP1 gene fusion was validated, and its ability to regulate autophagy and apoptosis balance, promote mitochondrial respiration, and glycolysis was demonstrated. Mouse model experiments further confirmed the promoting effect of CLTC-VMP1 on tumor growth and chemotherapy resistance. In summary, the CLTC-VMP1 gene fusion mediates energy metabolism reprogramming by regulating autophagy and apoptosis balance, which promotes chemotherapy resistance in OS.

Potential role of heteroplasmic mitochondrial DNA mutations in modulating the subtype-specific adaptation of oral squamous cell carcinoma to cisplatin therapy

Cancer cells are constantly evolving to adapt to environmental changes, particularly during exposure to drug treatment. In this work, we aimed to characterize genetic and epigenetic changes in mitochondrial DNA (mtDNA) that may increase the resistance of oral squamous cell carcinoma (OSCC) to cisplatin. We first derived drug-resistant cells from two human OSCC cell lines, namely SAS and H103, by continual cisplatin treatments for about 4 months. To determine mtDNA changes induced by cisplatin, we performed nanopore sequencing and quantitative polymerase chain reaction analysis of mtDNA extracted from the cells pre- and post-treatment. We also assessed the mitochondrial functions of the cells and their capacity to generate intracellular reactive oxygen species (ROS). We found that in the cisplatin-resistant cells derived from SAS, there was a reduction in mtDNA content and significant enrichment of a m.3910G > C mutation in the MT-ND1 gene. However, such changes were not detected in cisplatin-resistant H103 cells. The cisplatin treatment also altered methylation patterns in both SAS and H103 cells and decreased their sensitivity to ROS-induced cytotoxicity. We suggest that the sequence alterations and epigenetic changes in mtDNA and the reduction in mtDNA content could be key drivers of cisplatin resistance in OSCC. These mtDNA alterations may participate in cellular adaptation that serves as a response to adverse changes in the environment, particularly exposure to cytotoxic agents. Importantly, the observed mtDNA changes may be influenced by the distinct genetic landscapes of various cancer subtypes. Overall, this study reveals significant insights into cisplatin resistance driven by complex mtDNA dynamics, particularly in OSCC. This underscores the need for targeted therapies tailored to the genetic profiles of individual OSCC patients to improve disease prognosis.

MicroRNA-34a negatively regulates Netrin1 and mediates MEK/ERK pathway to regulate chemosensitivity of gastric cancer cells.

To explore the mechanism of action of MicroRNAs-34a (miR-34a) and Eurite growth guiding factor 1 (Netrin1) in cisplatin resistance in gastric cancer (GC), providing new clues for overcoming tumor resistance and optimizing anti-tumor therapy for GC. The Cancer Genome Atlas (TCGA), Differentially Expressed MicroRNAs (miRNAs) in human cancers (dbDEMC), and Starbase online databases were used to analyze the correlation between miR-34a and Netrin-1 and prognosis in GC, and to predict and verify the targeted binding of miR-34a to Netrin-1. The experimental methods including Cell transfection, real-time polymerase chain reaction (RT-PCR), Cell-Counting-Kit-8 (CCK8) assay, flow cytometry, wound scratch assay, transwell assay, and western blotting were used to investigate the effects of miR-34a and Netrin1 on chemotherapy resistance and biological characteristics in cisplatin-resistant GC cells (HGC27/DDP), and to analyze the molecular mechanism of cisplatin resistance. miR-34a expression was downregulated in gastric cancer clinical samples and cisplatin-resistant cells, while Netrin1 was upregulated, and was related to overall survival (OS). Upregulation of miR-34a can significantly reduce the IC50 value of cisplatin(0.65 vs 1.6 ng/mL) and Multidrug Resistance 1 (MDR-1) protein level, inhibit the proliferation activity, reduce the expression levels of proliferating cell nuclear antigen (PCNA) and ki-67 protein, and induce the increase of apoptosis rate and the enhancement of cycle arrest. Upregulation of miR-34a can also significantly reduce the expression level of Matrix metalloproteinase 9 (MMP9) protein, promote the expression of E-cadherin protein, reduce the wound healing rate and invasion number to inhibit migration and invasion ability in drug-resistant gastric cancer cells. Moreover, overexpression of Netrin1 on the basis of upregulation of miR-34a can weaken the above changes caused by upregulation of miR-34a. In addition, upregulation of miR-34a can significantly inhibit the Mitogen-activated protein kinase kinase (MEK) / Extracellular regulated protein kinases (ERK) pathway, while overexpression of Netrin1 can activate the MEK/ERK pathway, and inhibition of MEK/ERK pathway can effectively counteract the protein expression of Netrin1, and reverse changes in the expression of cisplatin IC50 and MDR-1 proteins caused by co-upregulation of miR-34a/Netrin1 in HGC27/DDP, as well as changes in proliferation, apoptosis, migration and invasion. In addition, upregulation of miR-34a can significantly inhibit the MEK/ERK pathway, while overexpression of Netrin1 can activate the MEK/ERK pathway. If the MEK/ERK pathway was inhibited, it can effectively counteract the protein overexpression of Netrin1, and reverse the changes in the expression of cisplatin IC50 and MDR-1 proteins in HGC27/DDP induced by co-upregulation of miR-34a / Netrin1, as well as changes in proliferation, apoptosis, migration and invasion. miR-34a targets and negatively regulates Netrin1 to mediate the proliferation, apoptosis, apoptosis, migration, and invasion of drug-resistant gastric cancer cells via the MEK/ERK pathway, and change the chemosensitivity in GC cells. miR-34a/Netrin1/MEK/ERK axis may serve as a novel therapeutic target for chemoresistance in GC, it is of great significance for overcoming drug resistance and developing new therapeutic strategies for GC.

Co-Delivery of VEGF siRNA and THPP via Metal-Organic Framework Reverses Cisplatin-Resistant Non-Small Cell Lung Cancer and Inhibits Metastasis through a MUC4 Regulating Mechanism.

Cisplatin resistance significantly impacts the antitumor efficacy of cisplatin chemotherapy and contributes to poor prognosis, including metastasis. In this study, we present the utilization of metal-organic framework (MOF) nanoparticles as the therapeutic component and drug loading scaffold for implementing a ternary combination therapeutic strategy to combat cisplatin-resistant lung cancer and metastasis. Specifically, by engineering MOFs (Cis@MOF-siVEGF) through the self-assembly of THPP as photosensitizer for photodynamic therapy (PDT), along with the incorporation of cisplatin (DDP) and VEGF siRNA (siVEGF), we propose the leverage of photodynamic-induced oxidative damage and gene silencing of the angiogenic factor to reverse cisplatin resistance and sensitize therapeutic potency. Our findings demonstrated that the chemo/photodynamic/antiangiogenic triple combination therapy via Cis@MOF-siVEGF under irradiation effectively inhibits cisplatin-resistant tumor growth and induces abscopal effects. Importantly, molecular mechanistic exploration suggested that MUC4 exerted regulatory effects on governing cancer metastasis, thus representing a potential immunotherapeutic target for cancer intervention. Overall, our study creates a MOFs-based multicomponent delivery platform for complementary therapeutic modules with synergistically enhanced antitumor efficacy and sheds light on potential regulatory mechanisms on cisplatin-resistance cancers.

Nuclear TOP1MT Confers Cisplatin Resistance via Pseudogene in HNSCC

Cisplatin resistance is one of the major causes of treatment failure in head and neck squamous cell carcinoma (HNSCC). There is an urgent need to uncover the underlying mechanism for developing effective treatment strategies. A quantitative proteomics assay was used to identify differential proteins in cisplatin-resistant cells. Mitochondrial topoisomerase I (TOP1MT) localization was determined using laser confocal microscopy and nucleocytoplasmic separation assay. Chromatin immunoprecipitation sequencing, dual-luciferase reporter assay, and RNA immunoprecipitation were used to identify the interaction between pseudogenes, miRNAs, and real genes. In vivo experiments verified the interaction between TOP1MT and pseudogenes on cisplatin resistance. TOP1MT was identified as a driving factor of cisplatin resistance in vitro, in vivo, and in HNSCC patients. Moreover, TOP1MT exceptionally translocated to the nucleus in cisplatin-resistant HNSCC cells in a signal peptide–dependent manner. Nuclear TOP1MT (nTOP1MT) transcriptionally regulated the mitochondrial functional pseudogene MTATP6P1, which bound to miR-137 and miR-491-5p as a competing endogenous RNA (ceRNA) and promoted the expression of MTATP6. An increase in MTATP6 enhanced mitochondrial oxidative phosphorylation (OXPHOS), which conferred cisplatin resistance in HNSCC. Our findings revealed that nTOP1MT transcriptionally activated MTAPT6P1 and increased MTATP6 expression via ceRNA, which facilitated OXPHOS and cisplatin resistance. These results provide novel insight for overcoming cisplatin resistance in HNSCC.

Tackling Anticancer Drug Resistance and Endosomal Escape in Aggressive Brain Tumors Using Bioelectronics.

Resistance mechanisms in brain tumors, such as medulloblastoma and glioblastoma, frequently involve the entrapment of chemotherapeutic agents within endosomes and the extracellular expulsion of drugs. These barriers to effective treatment are exacerbated in nanotechnology-based drug delivery systems, where therapeutic nanoparticles often remain confined within endosomes, thus diminishing their therapeutic efficacy. Addressing this challenge necessitates the development of novel strategies to enhance the efficiency of cancer therapies. This study tests the hypothesis that external electrical stimuli can modulate intracellular trafficking of chemotherapeutic drugs in common malignant brain tumors in children (medulloblastoma) and adults (glioblastoma) by using gold nanoparticles (GNPs). In our experiments, alternating current (AC) stimulation ranging from 1 kHz to 5 MHz and at a strength of 1 V/cm significantly reduced cell viability in drug-resistant medulloblastoma and enhanced delivery of GNPs in glioblastoma. Low-frequency AC resulted in a 50% increase in apoptosis compared to controls and an 8-fold increase in cell death in cisplatin-resistant medulloblastoma cells, accompanied by a substantial reduction in EC50 from 2.5 to 0.3 μM. Similarly, vincristine-resistant cells demonstrated a 4-fold enhancement in drug sensitivity. Furthermore, high-frequency AC facilitated a significant increase from 20 to 75% in the endosomal escape of GNPs in glioblastoma cells. These findings underscore the potential of AC to selectively disrupt cancer cell resistance mechanisms and bolster the efficacy of nanoparticle-based therapies. The results indicate the effectiveness of AC stimulation in circumventing the limitations inherent in current nanotechnology-based drug delivery systems but also illustrates its transformative potential for treating aggressive, drug-resistant brain tumors.

Hydrazide-Based Class I Selective HDAC Inhibitors Completely Reverse Chemoresistance Synergistically in Platinum-Resistant Solid Cancer Cells.

In this work, we have synthesized a set of peptoid-based histone deacetylase inhibitors (HDACi) with a substituted hydrazide moiety as zinc-binding group. Subsequently, all compounds were evaluated in biochemical HDAC inhibition assays and for their antiproliferative activity against native and cisplatin-resistant cancer cell lines. The hydrazide derivatives with a propyl or butyl substituent (compounds 5 and 6) emerged as the most potent class I HDAC selective inhibitors (HDAC1-3). Further, compounds 5 and 6 outperformed entinostat in cytotoxicity assays and were able to reverse chemoresistance in cisplatin-resistant A2780 (ovarian) and Cal27 (head-neck) cancer cell lines. Moreover, the hydrazide derivatives 5 and 6 showed strong synergism with cisplatin (combination indices <0.2), again outperforming entinostat, and increased DNA damage, p21, and pro-apoptotic BIM expression, leading to caspase-mediated apoptosis and cell death. Thus, compounds 5 and 6 represent promising lead structures for developing new HDACi capable of reversing chemoresistance in cisplatin resistant cancer cells.

Triple Combination of Entinostat, a Bromodomain Inhibitor, and Cisplatin Is a Promising Treatment Option for Bladder Cancer.

Cisplatin is part of the first-line treatment of advanced urothelial carcinoma. Cisplatin resistance is a major problem but may be overcome by combination treatments such as targeting epigenetic aberrances. Here, we investigated the effect of the class I HDACi entinostat and bromodomain inhibitors (BETis) on the potency of cisplatin in two pairs of sensitive and cisplatin-resistant bladder cancer cell lines. Cisplatin-resistant J82cisR and T24 LTT were 3.8- and 24-fold more resistant to cisplatin compared to the native cell lines J82 and T24. In addition, a hybrid compound (compound 20) comprising structural features of an HDACi and a BETi was investigated. We found complete (J82cisR) or partial (T24 LTT) reversal of chemoresistance upon combination of entinostat, JQ1, and cisplatin. The same was found for the BETis JQ35 and OTX015, both in clinical trials, and for compound 20. The combinations were highly synergistic (Chou Talalay analysis) and increased caspase-mediated apoptosis accompanied by enhanced expression of p21, Bim, and FOXO1. Notably, the combinations were at least 4-fold less toxic in non-cancer cell lines HBLAK and HEK293. The triple combination of entinostat, a BETi, and cisplatin is highly synergistic, reverses cisplatin resistance, and may thus serve as a novel therapeutic approach for bladder cancer.

Anticancer behavior of cyclometallated iridium(III)-tributyltin(IV) carboxylate schiff base complexes with aggregation-induced emission

Cyclometallated iridium(III) and organotin(IV) carboxylate complexes have shown potential application value in the field of anticancer. However, the widespread aggregation-caused quenching (ACQ) effect of these complexes is not conducive to the exploration of their targeting and anticancer mechanism, and the idea of aggregation-induced emission (AIE) effect can effectively solve this problem. Then, AIE-activated cyclometallated iridium(III)-tributyltin(IV) carboxylate Schiff base complexes were designed and prepared in this study. Complexes exhibited AIE effect in highly concentrated solution or aggregative state, which facilitated the investigation of subcellular tissue targeting (mitochondria) and cell morphology. Compared with cyclometallated iridium(III) complex and tributyltin(IV) carboxylate monomers, these complexes showed the better in-vitro anti-proliferative activity toward A549 cells, confirming the favorable synergistic anticancer activity. Even for A549/DDP (cisplatin-resistance) cells, these complexes also exhibited the better activity. In addition, complexes showed a mitochondrial apoptotic pathway. Therefore, cyclometallated iridium(III)-tributyltin(IV) carboxylate Schiff base complexes can be used as the potential substitutes for platinum-based drugs and gain further application.

Anticancer effects of emetine against cisplatin resistant pancreatic cancer cells via activation of Cyto-c/Caspase-9/Caspase-3/Bax/Bad axis

This investigation examines the potential pharmacotherapeutic efficacy of emetine, a natural alkaloid, against pancreatic ductal carcinoma, utilizing the PaCa3 cell line as a model. Employing a multifaceted approach, the study explores emetine's impact on cell viability, clonogenic potential, and apoptotic pathways, unravelling its molecular mechanisms. Additionally, an in-vivo assessment is conducted to evaluate emetine's antitumor efficacy against PaCa3 xenografts. Under standard conditions, PaCa3 cells were treated with varying emetine concentrations and subjected to MTT, clonogenic, DAPI, AO/EB, Annexin V-FITC/PI, and Western blot assays. In-vivo experiments involved the administration of emetine to female nude mice with PaCa3 xenografts, with subsequent measurement of tumor weight and volume. Statistical analyses included Tukey-test and ANOVA. Emetine demonstrated a significant and dose- and time-dependent cytotoxic effect on PaCa3 cells, reducing viability from 98% to 8% (***p&lt;0.001). Clonogenic assay indicated a substantial inhibition of colony formation. DAPI staining revealed nuclear chromatin condensation, while AO/EB staining indicated heightened apoptosis. Annexin V-FITC/PI assay exhibited a dose-dependent decrease in normal cell viability and an increase in apoptotic events. Western blot analysis showcased concentration-dependent downregulation of anti-apoptotic Bcl-2 and upregulation of pro-apoptotic markers. In-vivo experiments illustrated a dose-dependent reduction in tumor weight (5 g to 1.6 g) and volume (2400 mm³ to 844 mm³) with emetine treatment. In conclusion, emetine emerges as a potent anticancer agent against pancreatic ductal carcinoma, exhibiting cytotoxicity, clonogenic inhibition, and apoptotic induction in PaCa3 cells. The in-vivo study further highlights its promising therapeutic potential, laying the groundwork for future clinical studies in pancreatic cancer treatment.

Inhibition of Epithelial-Mesenchymal Transition and Migration in Cisplatin-resistant Cancer Through Combined Treatment With Cisplatin and SH003.

This study investigated the synergistic effects of combining cisplatin and SH003 treatment on the viability, apoptosis, cytotoxicity, migration and epithelial-mesenchymal transition (EMT) in cisplatin-resistant cancer cell lines YD-8/CIS, YD-9/CIS and YD-38/CIS. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to assess cell viability, while trypan blue exclusion assay was used to evaluate cytotoxicity. Flow cytometry and western blot analysis measured apoptotic cell death. Wound-healing assays evaluated cell migration and EMT markers. Combination index (CI) plots were used to evaluate the combinatory effects of the treatment. Combination therapy significantly reduced cell viability more effectively than each agent alone, as demonstrated by the MTT assay, with CI plots confirming notable synergism. Trypan blue exclusion assays indicated increased cell death and cytotoxicity in combination treatment than in both monotherapies, although the increase was not significant. Flow cytometry and western blot analysis revealed no significant synergistic effect on apoptotic cell death. However, wound-healing assays revealed that the combination of cisplatin and SH003 significantly inhibited cell migration and regulated EMT markers, indicating the potential reversal of EMT. Combining cisplatin and SH003 therapy may potentially be a more effective strategy for treating cisplatin-resistant cancer by increasing cytotoxicity and inhibiting metastasis. Further research is required to elucidate the underlying mechanisms and evaluate the in vivo efficacy of this combination therapy.

Pd(II)/1,10-phenanthroline complexes bearing arene ligands: On the role of N- vs O-coordination to tune their cellular activity and binding ability towards DNA and RNA

Three Pd(II)-based complexes of 1,10-phenanthroline and N- or O-coordinating ligands have been synthesised and tested with different relevant biosubstrates like double-stranded DNA, double and triple helix of RNA, DNA G-quadruplexes of different conformations and bovine serum albumin. Here a correlation between N- vs O-coordinating elements and binding mechanism emerged, where the N-coordinating ligands proved to be the most promising. These outcomes were confirmed also in the cellular experiments. The Pd(II) complex with naphthalene-1,8-diamine is the one that is able to be carried by BSA, to strongly bind nucleic acids, to produce reactive oxygen species (ROS) and to show the best cellular performances (poorly toxic towards healthy cells and highly toxic against the cisplatin-resistant cancer cell line). On the opposite, the complex with benzene-1,2-diolate may be sequestered by BSA, weakly binds nucleic acids, does not produce ROS and shows poor cellular activity. The complex with benzene-1,2-diamine stays in between. Other mechanistic details are discussed which show that the biophysical behaviour is the sum of the contribution of aromaticity, charge and N- or O-coordination.

New anti-ovarian cancer quinolone derivatives acting by modulating microRNA processing machinery.

MicroRNAs (miRNAs) play a crucial role in ovarian cancer (OC) pathogenesis and miRNA processing can be the object of pharmacological intervention. By exploiting our in-house quinolone library, we combined a cell-based screening with medicinal chemistry efforts, ultimately leading to derivative 33 with anti-OC activity against distinct cell lines (GI50 values 13.52-31.04 μM) and CC50 Wi-38 = 142.9 μM. Compound 33 retained anticancer activity against additional cancer cells and demonstrated a synergistic effect with cisplatin against cisplatin-resistant A2780 cells. Compound 33 bound TRBP by SPR (K D = 4.09 μM) and thermal shift assays and its activity was TRBP-dependent, leading to modulation of siRNA and miRNA maturation. Derivative 33 exhibited augmented potency against OC cells and a stronger binding affinity for TRBP compared to enoxacin, the sole quinolone identified as a modulator of miRNA maturation. Consequently, 33 represents a promising template for developing novel anti-OC agents with a distinctive mechanism of action.

T-Box Transcription Factor 2 Mediates Chemoresistance of Endometrial Cancer via Regulating FSP1-involved Ferroptosis.

Chemotherapy is increasingly being used in the first-line treatment of endometrial cancer (EC) patients. However, chemoresistance seriously affects its efficacy. Understanding the underlying molecular mechanisms is critical for EC treatment. We explored the regulatory role of T-Box transcription factor 2 (TBX2)-ferroptosis suppressor protein 1 (FSP1) axis in ferroptosis and chemoresistance of EC. Cisplatin-resistant cell line Ishikawa/DDP cells were utilized to generate TBX2 and FSP1 overexpression and knockdown stable cell lines by using lentivirus infection and puromycin selection. Cell viability and ferroptosis status were evaluated in EC cells with or without Cisplatin and/or FSP1 inhibitor (iFSP1) using CKK-8, lipid peroxidation, malondialdehyde, and lactate dehydrogenase release assays. Endometrial carcinoma xenograft mouse model was established to further explore the function of TBX2-FSP1 axis on ferroptosis and tumor progression in EC. TBX2 suppressed Cisplatin-induced ferroptosis through up-regulating FSP1 expression level in EC cells. On the contrary, knockdown of TBX2 reduced FSP1 expression and significantly promoted Cisplatin-induced ferroptosis. TBX2 or FSP1 overexpression and knockdown promote and inhibit EC tumor growth under Cisplatin treatment, respectively. Interestingly, silence FSP1 could reverse TBX2-mediated ferroptosis inhibition and tumor-promoting effect. TBX2-FSP1 axis inhibits ferroptosis and enhances the Cisplatin resistance, which will provide an important theoretical basis and potential solution for the clinical treatment of EC.

A tumor-promotional molecular axis CircMAPKBP1/miR-17-3p/TGFβ2 activates autophagy pathway to drive tongue squamous cell carcinoma cisplatin chemoresistance

Platinum-based chemotherapy is the first-line treatment for tongue squamous cell carcinoma (TSCC), but most patients rapidly develop resistance. Circular RNAs (circRNAs) are a class of critical regulators in the pathogenesis of several tumors, but their role in cisplatin resistance in TSCC has not been fully elucidated. Here we found that circMAPKBP1 was enriched in cisplatin resistant TSCC cells and was closely associated with enhanced autophagic activity. Functionally, silencing circMAPKBP1 significantly restored the chemosensitivity of cisplatin-resistant TSCC cells both in vitro and in vivo by suppressing autophagy. Mechanistically, circMAPKBP1 enhanced cisplatin sensitivity through the miR-17-3p/TGFβ2 axis by activating autophagy pathway. Data from clinical studies revealed that high expression of circMAPKBP1 and TGFβ2 was closely linked to a poor outcome in TSCC patients. We thus concluded that circMAPKBP1 is a tumor promoting factor and confers cisplatin sensitivity by activating the miR-17-3p/TGFβ2 axis-mediated autophagy. We propose that circMAPKBP1 may be a potential therapeutic target for TSCC.

TCEB2/HIF1A signaling axis promotes chemoresistance in ovarian cancer cells by enhancing glycolysis and angiogenesis

Ovarian cancer is an extremely malignant gynaecological tumour with a poor patient prognosis and is often associated with chemoresistance. Thus, exploring new therapeutic approaches to improving tumour chemosensitivity is important. The expression of transcription elongation factor B polypeptide 2 (TCEB2) gene is reportedly upregulated in ovarian cancer tumour tissues with acquired resistance, but the specific mechanism involved in tumour resistance remains unclear. In this study, we found that TCEB2 was abnormally highly expressed in cisplatin-resistant tumour tissues and cells. TCEB2 silencing also inhibited the growth and glycolysis of SKOV-3/cisplatin (DDP) and A2780/DDP cells. We further incubated human umbilical vein endothelial cells (HUVECs) with culture supernatants from cisplatin-resistant cells having TCEB2 knockdown. Results revealed that the migration, invasion, and angiogenesis of HUVECs were significantly inhibited. Online bioinformatics analysis revealed that the hypoxia-inducible factor-1A (HIF-1A) protein may bind to TCEB2, and TCEB2 silencing inhibited SKOV-3/DDP cell growth and glycolysis by downregulating HIF1A expression. Similarly, TCEB2 promoted HUVEC migration, invasion, and angiogenesis by upregulating HIF1A expression. In vivo experiments showed that TCEB2 silencing enhanced the sensitivity of ovarian cancer nude mice to cisplatin and that TCEB2 knockdown inhibited the glycolysis and angiogenesis of tumour cells. Our findings can serve as a reference for treating chemoresistant ovarian cancer.