Failure Of Chemotherapy Research Articles

MEF2A restrains cisplatin resistance in gastric cancer cells by modulating NFKBIA/NF-κB signaling pathway.

Cisplatin (DDP) resistance represents a pivotal contributing factor to chemotherapy failure and adverse patient outcomes in gastric cancer (GC). The objective of the present study was to investigate the roles and underlying mechanisms of myocyte enhancer factor 2A (MEF2A) in DDP resistance in GC. GC cell line AGS and MKN-45 cells were applied to construct DDP-resistant cells. CCK-8, colony formation, and flow cytometry methods were validated for determining the IC50 value of DDP and cell survival of GC cells. qRT-PCR and western blotting analysis quantified the molecular levels at mRNA and protein, respectively. Chromatin immunoprecipitation and dual-luciferase assays validated the molecular relationship between MEF2A and NF-κB inhibitor alpha (NFKBIA). Roles of MEF2A in in vivo were performed employing a xenograft model. The results showed that NFKBIA was greatly decreased in DDP-resistant AGS and MKN-45 cells compared to their respective parental cells. Increasing NFKBIA expression impaired the IC50 value of DDP and cell survival in DDP-resistant cells, while these alterations were rescued upon TNF-α treatment. Mechanistically, MEF2A acts as a transcriptional activator of NFKBIA, which led to the reduction of phosphorylation of p65 and cytoplasmic retention. Moreover, MEF2A overexpression promoted the sensitivity of GC cells to DDP and tumor growth, whereas these effects were partially reversed by NFKBIA silence. Collectively, MEF2A mitigated the DDP resistance in GC cells by modulatory actions on the NFKBIA/NF-κB signaling, shedding light on MEF2A/NFKBIA might be a promising intervention target for improving DDP resistance in GC.

Chemotherapy resistance in acute myeloid leukemia is mediated by A20 suppression of spontaneous necroptosis

Acute myeloid leukemia (AML) is a deadly hematopoietic malignancy. Although many patients achieve complete remission with standard induction therapy, a combination of cytarabine and anthracycline, ~40% of patients have induction failure. These refractory patients pose a treatment challenge, as they do not respond to salvage therapy or allogeneic stem cell transplant. Herein, we show that AML patients who experience induction failure have elevated expression of the NF-κB target gene tumor necrosis factor alpha-induced protein-3 (TNFAIP3/A20) and impaired necroptotic cell death. A20High AML are resistant to anthracyclines, while A20Low AML are sensitive. Loss of A20 in AML restores sensitivity to anthracycline treatment by inducing necroptosis. Moreover, A20 prevents necroptosis in AML by targeting the necroptosis effector RIPK1, and anthracycline-induced necroptosis is abrogated in A20High AML. These findings suggest that NF-κB-driven A20 overexpression plays a role in failed chemotherapy induction and highlights the potential of targeting an alternative cell death pathway in AML.

VASH2 enhances KIF3C-mediated EGFR-endosomal recycling to promote aggression and chemoresistance of lung squamous cell carcinoma by increasing tubulin detyrosination

Lung squamous cell carcinoma (LUSC) is associated with high mortality and has few therapeutic options. Chemotherapy remains the main treatment for LUSC patients, but multi-drug resistance has become the dominant challenge in the failure of chemotherapy in various cancers. Therefore, the effective therapeutic strategy for LUSC patients is an urgent unmet need. Here, we found vasohibin-2 (VASH2) was a prognostic biomarker for LUSC patients, and VASH2 promoted the malignant biological behaviors of LUSC cells and chemoresistance by increasing the detyrosination of α-tubulin. The high level of detyrosinated-tubulin was negatively associated with patient prognosis. Blocking the tubulin carboxypeptidase (TCP) activity of VASH2 inhibited the xenograft tumor growth and improved the treatment efficacy of paclitaxel in vivo. Results revealed that VASH2-induced increase in tubulin detyrosination boosted the binding of kinesin family member 3C (KIF3C) to microtubules and enhanced KIF3C-dependent endosomal recycling of EGFR, leading to the prolonged activation of PI3K/Akt/mTOR signaling. This study demonstrated that VASH2 was not only a prognostic biomarker but also a promising therapeutic target in LUSC, which offers a novel insight that combination of chemotherapy and EpoY, a TCP inhibitor, may be a promising treatment strategy for LUSC patients.

Endogenous Magnetic Lipid Droplet-Mediated Cascade-Targeted Sonodynamic Therapy as an Approach to Reversing Breast Cancer Multidrug Resistance.

Multidrug resistance (MDR) has emerged as a major barrier to effective breast cancer treatment, contributing to high rates of chemotherapy failure and disease recurrence. There is thus a pressing need to overcome MDR and to facilitate the efficient and precise treatment of breast cancer in a targeted manner. In this study, endogenous functional lipid droplets (IR780@LDs-Fe3O4/OA) were developed and used to effectively overcome the limited diffusion distance of reactive oxygen species owing to their amenability to cascade-targeted delivery, thereby facilitating precise and effective sonodynamic therapy (SDT) for MDR breast cancer. Initially, IR780@LDs-Fe3O4/OA was efficiently enriched within tumor sites in a static magnetic field, achieving the visualization of tumor treatment. Subsequently, the cascade-targeted SDT combined with the Fenton effect induced lysosome membrane permeabilization and relieved lysosomal sequestration, thus elevating drug concentration at the target site. This treatment approach also suppressed ATP production, thereby inhibiting P-glycoprotein-mediated chemotherapeutic drug efflux. This cascade-targeted SDT strategy significantly increased the sensitivity of MDR cells to doxorubicin, increasing the IC50 value of doxorubicin by approximately 10-fold. Moreover, the cascade-targeted SDT also altered the gene expression profiles of MDR cells and suppressed the expression of MDR-related genes. In light of these promising results, the combination of cascade-targeted SDT and conventional chemotherapy holds great clinical promise as an effective treatment modality with excellent biocompatibility that can improve MDR breast cancer patient outcomes.

Characteristics and Utilization of Hospitalizations Among Children With Medical Complexity.

Hospitalizations for children with medical complexity (CMC) have increased substantially over the past 2 decades and constitute a disproportionate percentage of hospitalization rates and costs among children. We sought to describe the etiology and utilization for hospitalizations of CMC using the Pediatric Clinical Classification System (PECCS). Using the 2019 Kids' Inpatient Database, we classified hospitalizations for CMC using the PECCS, which groups diagnoses into mutually exclusive, pediatric-specific categories. For the medical, surgical, and medical/surgical PECCS clinical groups, we reported diagnosis groups accounting for ≥1% of hospital encounters for that group. We described admission frequency, cost, payer, length of stay, and mortality rates within each diagnosis grouping using survey-weighted statistics. We identified 2 315 743 nonlivebirth hospitalizations, of which 712 139 (30.8%) were for CMC. Most (94.4%) hospitalizations occurred at a teaching hospital. Medical diagnosis comprised most hospitalizations (69.2%), whereas hospitalizations for surgical and medical/surgical conditions had a higher median cost. The most common diagnosis groups overall were encounters for chemotherapy, diabetic ketoacidosis, and respiratory failure, whereas the costliest were for necrotizing enterocolitis, transposition of the great vessels, and hypoplastic left heart syndrome. We evaluated the most common diagnoses and their associated resource use for hospitalized CMC using the PECCS, providing a more granular view on the etiology, utilization, cost, and outcomes of hospitalizations for CMC. These topics represent high-impact areas for further research and quality efforts for CMC.

An Alternatively Spliced Gain-of-Function NT5C2 Isoform Contributes to Chemoresistance in Acute Lymphoblastic Leukemia.

Relapsed or refractory B-cell acute lymphoblastic leukemia (B-ALL) is a major cause of pediatric cancer-related deaths. Relapse-specific mutations do not account for all chemotherapy failures in B-ALL patients, suggesting additional mechanisms of resistance. By mining RNA sequencing datasets of paired diagnostic/relapse pediatric B-ALL samples, we discovered pervasive alternative splicing (AS) patterns linked to relapse and affecting drivers of resistance to glucocorticoids, antifolates, and thiopurines. Most splicing variations represented cassette exon skipping, "poison" exon inclusion, and intron retention, phenocopying well-documented loss-of-function mutations. In contrast, relapse-associated AS of NT5C2 mRNA yielded an isoform with the functionally uncharacterized in-frame exon 6a. Incorporation of the 8-amino acid sequence SQVAVQKR into this enzyme created a putative phosphorylation site and resulted in elevated nucleosidase activity, which is a known consequence of gain-of-function mutations in NT5C2 and a common determinant of 6-mercaptopurine resistance. Consistent with this finding, NT5C2ex6a and the R238W hotspot variant conferred comparable levels of resistance to 6-mercaptopurine in B-ALL cells both in vitro and in vivo. Furthermore, both NT5C2ex6a and the R238W variant induced collateral sensitivity to the inosine monophosphate dehydrogenase inhibitor mizoribine. These results ascribe to splicing perturbations an important role in chemotherapy resistance in relapsed B-ALL and suggest that inosine monophosphate dehydrogenase inhibitors, including the commonly used immunosuppressive agent mycophenolate mofetil, could be a valuable therapeutic option for treating thiopurine-resistant leukemias. Significance: Alternative splicing is a potent mechanism of acquired drug resistance in relapsed/refractory acute lymphoblastic leukemias that has diagnostic and therapeutic implications for patients who lack mutations in known chemoresistance genes.

Understanding Bacterial Roles in Cancer Chemo-resistance: A Signaling Pathway Mapping Study

Introduction: Chemoresistance is one of the leading causes of chemotherapy failure among cancer patients. Out of several hypotheses proposed for chemoresistance, bacteria-mediated chemoresistance to cancer drugs has not been well established. Thus, the aim of this review is to map the pathways by which bacteria exhibit chemoresistance in specific cancers. Material and Methods: Relevant articles on bacteria-mediated chemoresistance in cancer were retrieved by conducting a systematic search across PubMed, Scopus and Web of Science databases. The search was limited to English original articles published until 15th December 2023. Results: A total of nine articles were included to map the pathways involved in chemoresistance. Numerous pathways have been connected to various forms of cancer, such as autophagy pathway in colorectal and esophageal cancers by Fusobacterium nucleatum causing oxaliplatin and 5-FU resistance; DNA damage response pathway also by Fusobacterium nucleatum promoting CDDP resistance in esophageal cancer; Porphyromonas gingivalis led to oral and esophageal cancer resistance to paclitaxel via JAK/STAT pathway. NF-κB pathway involved in gastric cancer in the presence of Helicobacter pylori towards cisplatin, and also 5-FU resistance via the apoptotic pathway. Cellular metabolism modulation by Lactobacillus iners was also implicated in cervical cancer chemoresistance. Conclusion: We conclude that bacteria can mediate chemoresistance not merely to antibiotics but also to anticancer drugs. Thus, a detailed understanding of the pathways associated with chemoresistance mediated via bacteria might help in targeting these pathways or antibiotics to prevent bacterial growth could help overcome resistance.

Discovery of novel third generation P-glycoprotein inhibitors bearing an azo moiety with MDR-reversing effect

P-glycoprotein (P-gp)-caused multidrug resistance (MDR) is a crucial factor in the cancer chemotherapy failure. Herein, a total of twenty two azo-containing WK-X-34 (WK34, a third generation P-gp inhibitor) derivatives were synthesized as novel P-gp inhibitors. Biological evaluation revealed that compound 7i effectively reversed P-gp-mediated MDR in K562/A02 cells, with a higher reversal fold (RF) value than WK34 (142.79 vs. 64.41). Further investigation indicated that 7i dose-dependently inhibited P-gp function, without affecting its expression. CETSA results illustrated that 7i could obviously improve P-gp stability, suggesting its high affinity with P-gp. Molecular docking analysis revealed that 7i fit well into P-gp's binding pocket, thus displaying potent reversal effect on P-gp-mediated tumor MDR Optical properties evaluation confirmed that azo-containing 7i can undergo reversible changes in the cis and trans configurations under the irradiation of 365 nm and 520 nm wavelength of light. Notably, the configuration change of azo might affect the MDR-reversal potency, and cis-7i has a lower RF value than trans-7i (122.70 vs. 142.79), suggesting that development of photoswitchable P-gp inhibitors might be a novel strategy to reduce the systemic toxicity caused by indiscriminate inhibition of P-gp by traditional inhibitors. Collectively, 7i, as a novel P-gp inhibitor, warranted further investigation.

Antisense oligonucleotide facilitate the photothermal therapy of Mxene-based nanoplatform for drug-resistant breast cancer

Breast cancer has become the most common form of cancer worldwide. Chemotherapy failure, primarily due to drug resistance, necessitates the development of new therapeutic strategies. In this study, ultrathin Ti3C2 nanosheets are utilized as photothermal agents and nanocarriers. We developed a multifunctional Ti3C2-based nanoplatform (214.7 nm) through layer-by-layer absorption of HSP90 antisense oligonucleotide (ASO) and doxorubicin (DOX), with surface modification using hyaluronic acid (HA). In a simulated acidic tumor microenvironment in vitro, 90 % of the drug was released within 36 hours. Additionally, Under 808 nm irradiation (2.0 W/cm²), MCF-7/ADM cell viability assays revealed the following results: HA-Ti3C2 (57 %), HA-Ti3C2@ASO (HT@A) (41 %), and HA-Ti3C2@ASO/DOX (HT@AD) (26 %), which shown the synergistic inhibitory effects of this multifunctional nanoplatform. Herein, this nanosystem exhibits enhanced biocompatibility, superior photothermal performance, and stimuli-responsive drug release behavior, making it a promising candidate for effective inhibition of cancer cell proliferation and migration.

Cancer and its Prevalent Treatment Strategies - A Review

One of the main forms of cancer treatment is chemotherapy. Chemotherapy failure is a common occurrence, primarily because of dose-limiting toxicity linked to medication resistance. Effective treatment resistance management is essential for chemotherapy to be successful. Numerous reports in Chinese literature suggest that organic materials can overcome medication resistance in cancer cells, and these findings should be shared with scientific and industrial groups. The reports were condensed into four categories by us: 1. research on cell line models in-vitro; 2. serum pharmacokinetics; 3. in-vivo research employing animal models; and 4. clinical research. For the first time, antidrug resistance activity was found in 14 single compounds. Drugs have been proven to overcome drug resistance in-vitro in a dose-dependent manner by blocking drug transporters, cell detoxification ability, or cell apoptosis sensitivity, even at nontoxic and subtoxic concentrations. Research conducted in-vivo revealed that herbal extracts, single components, and formulations all exhibited strong antidrug resistance properties. A significant number of individual chemicals, herbal extracts, and combinations have been applied in clinical settings to treat a range of illnesses, including cancer. Comprehensive information on the utilization of natural compounds in China to combat drug resistance in cancer cells is provided by this review, which could help in the creation of organic substances for the therapeutic treatment of drug resistance in cancer patients.

1521P Efficacy and safety of liposomal irinotecan plus S-1 in patients with metastatic pancreatic cancer after failure of first-line gemcitabine-based chemotherapy: Result of a phase I/II study

1521P Efficacy and safety of liposomal irinotecan plus S-1 in patients with metastatic pancreatic cancer after failure of first-line gemcitabine-based chemotherapy: Result of a phase I/II study

Dysregulated arginine metabolism in precursor B-cell acute lymphoblastic leukemia in children: a metabolomic study

BackgroundPrecursor B-cell acute lymphoblastic leukemia (B-ALL) is the most common cancers in children. Failure of induction chemotherapy is a major factor leading to relapse and death in children with B-ALL. Given the importance of altered metabolites in the carcinogenesis of pediatric B-ALL, studying the metabolic profile of children with B-ALL during induction chemotherapy and in different minimal residual disease (MRD) status may contribute to the management of pediatric B-ALL.MethodsWe collected paired peripheral blood plasma samples from children with B-ALL at pre- and post-induction chemotherapy and analyzed the metabolomic profiling of these samples by ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS). Healthy children were included as controls. We selected metabolites that were depleted in pediatric B-ALL and analyzed the concentrations in pediatric B-ALL samples. In vitro, we study the effects of the selected metabolites on the viability of ALL cell lines and the sensitivity to conventional chemotherapeutic agents in ALL cell lines.ResultsForty-four metabolites were identified with different levels between groups. KEGG pathway enrichment analyses revealed that dysregulated linoleic acid (LA) metabolism and arginine (Arg) biosynthesis were closely associated with pediatric B-ALL. We confirmed that LA and Arg were decreased in pediatric B-ALL samples. The treatment of LA and Arg inhibited the viability of NALM-6 and RS4;11 cells in a dose-dependent manner, respectively. Moreover, Arg increased the sensitivity of B-ALL cells to L-asparaginase and daunorubicin.ConclusionArginine increases the sensitivity of B-ALL cells to the conventional chemotherapeutic drugs L-asparaginase and daunorubicin. This may represent a promising therapeutic approach.

Immune killer cells treatment for previously treated stage IV NSCLC patients

The 5-year survival is poor for stage IV non-small cell lung cancer (NSCLC). Recently, cell immunotherapy has emerged as a new treatment strategy. This study aimed to evaluate the efficacy and safety of Immune killer cells (IKC) in patients with stage IV NSCLC after the failure of prior chemotherapy. This study enrolled 26 patients with stage IV NSCLC who failed at least two lines of chemotherapy with or without targeted therapy. The IKC was given alone weekly for 24 weeks. The primary endpoint was progression-free survival (PFS). Secondary outcomes included overall survival (OS), pain intensity, quality of life (QOL), and safety. The median PFS for the intent-to-treat (ITT) population (i.e., all enrolled patients) was 3.8 month. In the per-protocol (PP) population (i.e., patients receiving > 12 IKC infusions), the median PFS was 5.6 months. Moreover, the ITT population showed a 1-year survival rate of 60.0%, while that for the PP population was 85.7%. Only 7 out of 200 AEs (3.5%) were related to the IKC infusion, and they were all rated as grade 1 in severity. The IKC infusion was well tolerated. This novel immunotherapy prolonged the PFS and improved the survival compared with historical data. It might be a potential treatment strategy for stage IV NSCLC patient who failed prior chemotherapy.ClinicalTrials.gov identifier: NCT03499834.

In-Silico and In-Vitro Investigation of Key Long Non-coding RNAs Involved in 5-Fluorouracil Resistance in Colorectal Cancer Cells: Analyses Highlighting NEAT1 and MALAT1 as Contributors.

Background Acquired resistance to 5-fluorouracil (5-FU) frequently results in chemotherapy failure and disease recurrence in advanced colorectal cancer (CRC) patients. Research has demonstrated that dysregulation of long non-coding RNAs (lncRNAs) mediates the development of chemotherapy resistance in cancerous cells. The present study aims to identify key lncRNAs associated with 5-FU resistance in CRC using bioinformatic and experimental validation approaches. Methods The Gene Expression Omnibus (GEO) dataset GSE119481, which contains miRNA expression profiles of the parental CRC HCT116 cell line (HCT116/P) and its in-vitro established 5-FU-resistant sub-cell line (HCT116/FUR), was downloaded. Firstly, differentially expressed microRNAs (DEmiRNAs) between the parental and 5-FU resistance cells were identified. LncRNAs and mRNAs were then predicted using online databases. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed to uncover relevant biological mechanisms and pathways. Networks integrating lncRNAs, miRNAs, and mRNAs interactions were constructed, and topological analyses were used to identify key lncRNAs associated with 5-FU resistance. An in-vitro model of the HCT116/FUR sub-cell line was developed by exposing the HCT116/P cell line to increasing concentrations of 5-FU. Finally, real-time quantitative PCR (RT-qPCR) was performed on total RNA extracted from the HCT116/P cell line and the HCT116/FUR sub-cell line to validate the in-silico predictions of key lncRNAs. Results A total of 32 DEmiRNAs were identified. Enrichment analysis demonstrated that these DEmiRNAs were mainly enriched in several cancer hallmark pathways that regulate cell growth, cell cycle, cell survival, inflammation, immune response, and apoptosis. The predictive analysis identified 237 unique lncRNAs and 123 mRNAs interacting with these DEmiRNAs. The pathway analysis indicated that most of these predicted genes were enriched in the cellular response to starvation, protein polyubiquitination, chromatin remodeling, and negative regulation of gene expression. Topological analyses of the lncRNA-miRNA-mRNA network highlighted the nuclear enriched abundant transcript 1 (NEAT1), metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), and Opa interacting protein 5 antisense RNA 1 (OIP5-AS1) as central lncRNAs. Experimental analysis by RT-qPCR confirmed that the expression levels of NEAT1 and MALAT1 were significantly increased in HCT116/FUR cells compared to HCT116/P cells. However, no significant difference was observed in the OIP5-AS1 expression level between the two cells. Conclusion Our findings specifically highlight MALAT1 and NEAT1 as significant contributors to 5-FU resistance in CRC. These lncRNAs are promising biomarkers for diagnosing and predicting outcomes in CRC.

Functionalized Polymeric Micelles for Targeted Cancer Therapy: Steps from Conceptualization to Clinical Trials.

Cancer is still ranked among the top three causes of death in the 30- to 69-year-old age group in most countries and carries considerable societal and macroeconomic costs that differ depending on the cancer type, geography, and patient gender. Despite advances in several pharmacological approaches, the lack of stability and specificity, dose-related toxicity, and limited bioavailability of chemotherapy (standard therapy) pose major obstacles in cancer treatment, with multidrug resistance being a driving factor in chemotherapy failure. The past three decades have been the stage for intense research activity on the topic of nanomedicine, which has resulted in many nanotherapeutics with reduced toxicity, increased bioavailability, and improved pharmacokinetics and therapeutic efficacy employing smart drug delivery systems (SDDSs). Polymeric micelles (PMs) have become an auspicious DDS for medicinal compounds, being used to encapsulate hydrophobic drugs that also exhibit substantial toxicity. Through preclinical animal testing, PMs improved pharmacokinetic profiles and increased efficacy, resulting in a higher safety profile for therapeutic drugs. This review focuses on PMs that are already in clinical trials, traveling the pathways from preclinical to clinical studies until introduction to the market.

Exploration of ETV6::ABL1-positive AML with concurrent NPM1 and FLT3-ITD mutations.

ETV6::ABL1 is a rare fusion gene that found in MPN, ALL, and AML. It has a complex and diverse formation mechanism due to the reciprocal orientations of the ETV6 and ABL1 genes relative to the centromeres. NPM1 is frequently mutated in adult AML, often accompanied by FLT3-ITD, which suggests molecular synergisms in AML pathogenesis. Previous reports on ETV6::ABL1 mostly focus on FLT3-ITD. In this study, we present a case of AML with ETV6::ABL1, along with NPM1 and FLT3-ITD. The patient showed a rapid increase in primitive cells at the initial stage, along with the presence of immature granulocytes and erythrocytes. Through cytogenetic analysis, fluorescence in situ hybridization (FISH), and RNA-seq, we elucidated the mechanism behind the formation of the ETV6::ABL1 fusion gene. Despite conventional chemotherapy failure and rapid tumor proliferation, we attempted to add FLT3 inhibitor sorafenib to the treatment, along with chemotherapy bridging to haploidentical transplantation. After haplo-HSCT, a combination of sorafenib and dasatinib was administered as maintenance therapy. The patient achieved complete remission (CR) and maintained it for 11 months. The intricate genetic landscape observed in this case presents diagnostic dilemmas and therapeutic challenges, emphasizing the importance of a comprehensive understanding of its implications for disease classification, risk stratification, and treatment selection.

Clinical Outcomes of Enfortumab Vedotin in Advanced Urothelial Carcinoma With Prior Avelumab Versus Pembrolizumab Therapy.

This study retrospectively evaluated whether enfortumab vedotin (EV) monotherapy is effective as a late-line treatment according to prior treatment type in patients with advanced urothelial carcinoma (UC). We assessed consecutive patients from the Uro-Oncology Group in the Kyushu study population with lower and upper urinary tract cancer treated with EV monotherapy after platinum-based chemotherapy and immune checkpoint inhibitor therapy failure between December 2021 and March 2024. In particular, patients receiving avelumab maintenance or pembrolizumab therapy before EV for advanced UC were analyzed and compared according to the response rate, progression-free survival (PFS), and overall survival (OS). Of the 80 enrolled patients, 31 and 49 received avelumab and pembrolizumab before EV therapy, respectively. The avelumab and pembrolizumab groups had comparable objective response rates (48.4% vs. 44.9%, p=0.820) and disease control rates (77.4% vs. 67.3%, p=0.448). These two groups showed no significant difference in PFS from the initiation of EV (median: 6.4 months vs. 4.2 months, p=0.184); meanwhile, the avelumab group had better OS from the initiation of EV than the pembrolizumab group (median: 16.0 months vs. 10.2 months, p=0.019). Moreover, the median OS after first-line chemotherapy initiation was longer in the avelumab group than in the pembrolizumab group (40.3 months vs. 24.7 months, p=0.054). On multivariate analysis, avelumab maintenance therapy before EV reduced the mortality risk by 47% (95% confidence interval=0.27-1.03; p=0.059). EV monotherapy after avelumab maintenance therapy provides favorable survival outcomes in patients with advanced UC.

RREB1-mediated SUMOylation enhancement promotes chemoresistance partially by transcriptionally upregulating UBC9 in colorectal cancer.

Chemoresistance is a main cause of chemotherapy failure and tumor recurrence. The effects of global protein SUMOylation on chemoresistance in colorectal cancer (CRC) remains to be investigated. Herein, we have proposed that the elevated SUMO2/3-modified proteins confer 5-fluorouracil (5-FU) chemoresistance acquisition in CRC. The SUMOylation levels of global proteins in CRC cell lines were elevated compared with normal colon cell line NCM460. 5-FU treatment obviously reduced SUMOylation of global proteins in 5-FU-sensitive CRC cells including HT29, HCT116 and HCT-8. However, in 5-FU-resistant HCT-8/5-FU cells, the expression level of SUMO2/3-modified proteins was increased under 5-FU exposure in a concentration-dependent manner. 5-FU treatment combined with SUMOylation inhibitor ML-792 significantly increased the sensitivity of 5-FU-resistant cells to 5-FU and reduced colony formation numbers in HCT-8/5-FU cells. And UBC9-mediated SUMOylation elevation contributes to 5-FU resistance in HCT116 cells. Moreover, we also identified RREB1 as a regulator of SUMOylation profiling of global cellular proteins via directly binding to the promoter of UBC9. Overexpression of RREB1 promoted 5-FU resistance in CRC, which was partially abolished by treatment of inhibitor ML-792. In conclusion, RREB1-enhanced protein SUMOylation contributes to 5-FU resistance acquisition in CRC.

Gut-derived metabolite 3-methylxanthine enhances cisplatin-induced apoptosis via dopamine receptor D1 in a mouse model of ovarian cancer.

Platinum-based chemotherapy failure represents a significant challenge in the management of ovarian cancer (OC) and contributes to disease recurrence and poor prognosis. Recent studies have shed light on the involvement of the gut microbiota in modulating anticancer treatments. However, the precise underlying mechanisms, by which gut microbiota regulates the response to platinum-based therapy, remain unclear. Here, we investigated the role of gut microbiota on the anticancer response of cisplatin and its underlying mechanisms. Our results demonstrate a substantial improvement in the anticancer efficacy of cisplatin following antibiotic-induced perturbation of the gut microbiota in OC-bearing mice. 16S rRNA sequencing showed a pronounced alteration in the composition of the gut microbiome in the cecum contents following exposure to cisplatin. Through metabolomic analysis, we identified distinct metabolic profiles in the antibiotic-treated group, with a notable enrichment of the gut-derived metabolite 3-methylxanthine in antibiotic-treated mice. Next, we employed a strategy combining transcriptome analysis and chemical-protein interaction network databases. We identified metabolites that shared structural similarity with 3-methylxanthine, which interacted with genes enriched in cancer-related pathways. It is identified that 3-methylxanthinesignificantly enhances the effectiveness of cisplatin by promoting apoptosis both in vivo and in vitro. Importantly, through integrative multiomics analyses, we elucidated the mechanistic basis of this enhanced apoptosis, revealing a dopamine receptor D1-dependent pathway mediated by 3-methylxanthine. This study elucidated the mechanism by which gut-derived metabolite 3-methylxanthine mediated cisplatin-induced apoptosis. Our findings highlight the potential translational significance of 3-methylxanthine as a promising adjuvant in conjunction with cisplatin, aiming to improve treatment outcomes for OC patients.IMPORTANCEThe precise correlation between the gut microbiota and the anticancer effect of cisplatin in OC remains inadequately understood. Our investigation has revealed that manipulation of the gut microbiota via the administration of antibiotics amplifies the efficacy of cisplatin through the facilitation of apoptosis in OC-bearing mice. Metabolomic analysis has demonstrated that the cecum content from antibiotic-treated mice exhibits an increase in the levels of 3-methylxanthine, which has been shown to potentially enhance the therapeutic effectiveness of cisplatin by an integrated multiomic analysis. This enhancement appears to be attributable to the promotion of cisplatin-induced apoptosis, with 3-methylxanthine potentially exerting its influence via the dopamine receptor D1-dependent pathway. These findings significantly contribute to our comprehension of the impact of the gut microbiota on the anticancer therapy in OC. Notably, the involvement of 3-methylxanthine suggests its prospective utility as a supplementary component for augmenting treatment outcomes in patients afflicted with ovarian cancer.

An Alternatively Spliced Gain-of-Function NT5C2 Isoform Contributes to Chemoresistance in Acute Lymphoblastic Leukemia.

Relapsed or refractory B-cell acute lymphoblastic leukemia (B-ALL) is a major cause of pediatric cancer-related deaths. Relapse-specific mutations do not account for all chemotherapy failures in B- ALL patients, suggesting additional mechanisms of resistance. By mining RNA-seq datasets of paired diagnostic/relapse pediatric B-ALL samples, we discovered pervasive alternative splicing (AS) patterns linked to relapse and affecting drivers of resistance to glucocorticoids, anti-folates, and thiopurines. Most splicing variations represented cassette exon skipping, "poison" exon inclusion, and intron retention, phenocopying well-documented loss-of-function mutations. In contrast, relapse-associated AS of NT5C2 mRNA yielded an isoform with the functionally uncharacterized in-frame exon 6a. Incorporation of the 8-amino acid sequence SQVAVQKR into this enzyme created a putative phosphorylation site and resulted in elevated nucleosidase activity, which is a known consequence of gain-of-function mutations in NT5C2 and a common determinant of 6-mercaptopurine (6-MP) resistance. Consistent with this finding, NT5C2ex6a and the R238W hotspot variant conferred comparable levels of resistance to 6-MP in B-ALL cells both in vitro and in vivo. Furthermore, both the NT5C2ex6a and R238W variants induced collateral sensitivity to the inosine monophosphate dehydrogenase (IMPDH) inhibitor mizoribine. These results ascribe an important role for splicing perturbations in chemotherapy resistance in relapsed B-ALL and suggest that IMPDH inhibitors, including the commonly used immunosuppressive agent mycophenolate mofetil, could be a valuable therapeutic option for treating thiopurine-resistant leukemias.