Resistant Cells Research Articles

DLK1 Is Associated with Stemness Phenotype in Medullary Thyroid Carcinoma Cell Lines

Medullary thyroid carcinoma (MTC) is a rare and aggressive tumor, often requiring systemic treatment in advanced or metastatic stages, where drug resistance presents a significant challenge. Given the role of cancer stem cells (CSCs) in cancer recurrence and drug resistance, we aimed to identify CSC subpopulations within two MTC cell lines harboring pathogenic variants in the two most common MEN2-associated codons. We analyzed 15 stemness-associated markers, along with well-established thyroid stem cell markers (CD133, CD44, and ALDH1), a novel candidate (DLK1), and multidrug resistance proteins (MRP1 and MRP3). The ability to efflux the fluorescent dye Hoechst 3342 and form spheroids, representing CSC behavior, was also assessed. MZ-CRC-1 cells (p.M918T) displayed higher expressions of canonical markers, DLK1, and MRP proteins than TT cells (p.C634W). MZ-CRC-1 cells also formed more spheroids and showed less dye accumulation (p < 0.0001). Finally, we observed that DLK1+ cells (those expressing DLK1) in both cell lines exhibited significantly higher levels of stemness markers compared to DLK1− cells (those lacking DLK1 expression). These findings underscore DLK1’s role in enhancing the stemness phenotype, providing valuable insights into MTC progression and resistance and suggesting potential therapeutic implications.

ZNF480 Accelerates Chemotherapy Resistance in Breast Cancer by Competing With TRIM28 and Stabilizing LSD1 to Upregulate the AKT-GSK3β-Snail Pathway.

Zinc finger protein 480 (ZNF480) may interact with lysine-specific demethylase 1 (LSD1), which is highly expressed in many malignant tumors; however, ZNF480 expression has not previously been investigated in breast cancer. Therefore, we explored the expression and molecular mechanisms of ZNF480 in breast cancer. According to public databases and immunohistochemical staining analysis, ZNF480 is highly expressed in the tissue of patients with breast cancer, and ZNF480 expression is positively correlated with advanced TNM stage (p = 0.036), lymph node metastasis (p = 0.012), and poor prognosis (p = 0.005). ZNF480 overexpression enhances breast cancer cell proliferation, migration, and stemness by activating AKT-GSK3β-Snail signaling both in vitro and in vivo. Moreover, ZNF480 binds to LSD1 through its KRAB domain, thereby activating AKT signaling. Mass spectrometry and co-immunoprecipitation revealed that ZNF480 abrogates ubiquitination degradation and subsequently stabilizes LSD1 through competitive binding with TRIM28. Ipragliflozin was identified as a small-molecule inhibitor of ZNF480 and LSD1 interaction that may block breast cancer progression. Moreover, ZNF480 expression was significantly higher in treatment-resistant patients than in treatment-sensitive patients. Thus, ipragliflozin may neutralize neoadjuvant chemotherapy resistance induced by ZNF480 overexpression. Overall, elevated ZNF480 expression is positively associated with poor patient outcomes. Mechanistically, ZNF480 accelerates proliferation and neoadjuvant chemotherapy resistance in breast cancer cells via the AKT-GSK3β-Snail pathway by interacting with and stabilizing LSD1 in a competitive manner within TRIM28. This research has implications for developing targeted drugs against chemotherapy resistance in breast cancer.

Androgen Receptor Mediates Dopamine Agonist Resistance by Regulating Intracellular Reactive Oxygen Species in Prolactin-Secreting Pituitary Adenoma.

Aims: Dopamine agonists (DAs) are the first-line treatment for patients with prolactin-secreting pituitary adenoma (PRL adenoma). However, a subset of individuals exhibits poor responses, known as DA resistance. Previous studies have reported that DA resistance is more prevalent in male patients. This study aims to investigate the relationship between androgen receptor (AR) expression and DA resistance, as well as to explore underlying mechanisms of AR-mediated DA resistance. Results: Our results demonstrated that patients with higher AR expression exhibit greater resistance to DA in our cohort of DA-resistant PRL adenoma. Furthermore, AR was found to be involved in cell proliferation, PRL secretion, and resistance to bromocriptine (BRC) both in vitro and invivo. Mechanistically, we demonstrated that intracellular reactive oxygen species (ROS) function as upstream mediators of apoptosis and ferroptosis following BRC treatment. As a ligand-dependent transcription factor, AR could translocate to the nucleus and transcriptionally promote NFE2-like bZIP transcription factor 2 (NRF2) expression, which regulates intracellular ROS levels, thereby enhancing cell viability and conferring DA resistance to pituitary adenoma (PA) cells. Finally, AR targeting agents were used to inhibit AR signaling, downregulate NRF2 transcription, and sensitize PA cells to BRC treatment. Conclusion and Innovation: We demonstrated that AR plays a crucial role in mediating DA resistance in PRL adenoma. Mechanistically, AR promotes cell proliferation and PRL secretion and confers drug resistance by transcriptionally regulating NRF2 expression to maintain redox homeostasis in PA cells. Finally, combining AR targeting agents with BRC shows promise as a therapeutic strategy for treating PRL adenomas. Antioxid. Redox Signal. 00, 000-000.

Photothermally Reinforced Nanozyme Remodeling Tumor Microenvironment of Redox and Metabolic Homeostasis to Enhance Ferroptosis in Tumor Therapy.

The acidity and high GSH level in the tumor microenvironment (TME) greatly limit the antitumor activity of nanozymes. Thus, enhancing nanozymes' activity is fundamentally challenging in tumor therapy. Although the combination of photothermal therapy (PTT) and nanozymes can enhance the catalytic activity, cancer cells will overexpress heat shock proteins (HSPs) at high temperature, aggravating the heat resistance of tumor cells, which in turn compromises the outcome of chemodynamic therapy. Herein, we propose an iron-doped metal-organic framework nanozyme (IB@Fe-ZIF8@PDFA) that can be activated under the weak acidity and high level of GSH, demonstrating the activities of GSH oxidation (GSH-OXD), peroxidase (POD), and NADH oxidase (NADH-OXD). Under laser irradiation, it displays photothermal-enhanced multienzyme activities to simultaneously eliminate tumors and inhibit tumor metastasis. While consuming endogenous GSH, IB@Fe-ZIF8@PDFA promotes the decomposition of H2O2 into ·OH, enhancing ferroptosis in tumor cells. Surprisingly, IB@Fe-ZIF8@PDFA nanozyme can oxide NADH and subsequently limit the ATP supply, reducing the expression of HSPs and significantly weakening the heat resistance of tumor cells during PTT. Meanwhile, H2O2 is generated during this procedure, which can endogenously replenish the consumed H2O2. Thus, this IB@Fe-ZIF8@PDFA nanozyme constitutes a self-cascading platform to consume GSH and NADH, endogenously replenish the H2O2 and continuously generate ·OH to facilitate ferroptosis by disrupting the redox and metabolic homeostasis in tumor cells, achieving tumor elimination and tumor metastasis inhibition.

Retraction: SH2 Modified STAT1 Induces HLA-I Expression and Improves IFN-γ Signaling in IFN-α Resistant HCV Replicon Cells.

Retraction: SH2 Modified STAT1 Induces HLA-I Expression and Improves IFN-γ Signaling in IFN-α Resistant HCV Replicon Cells.

STUB1 suppresses paclitaxel resistance in ovarian cancer through mediating HOXB3 ubiquitination to inhibit PARK7 expression

Paclitaxel (PTX) is a first-line drug for ovarian cancer (OC) treatment. However, the regulatory mechanism of STUB1 on ferroptosis and PTX resistance in OC remains unclear. Genes and proteins levels were evaluated by RT-qPCR, western blot and IHC. Cell viability and proliferation were measured by CCK-8 and clone formation. The changes of mitochondrial morphology were observed under a transmission electron microscope (TEM). Reactive oxygen species (ROS), iron, malondialdehyde (MDA) and glutathione (GSH) were measured using suitable kits. The interactions among STUB1, HOXB3 and PARK7 were validated using Co-IP, and dual luciferase reporter assay. Our study found that STUB1 was decreased and PARK7 was increased in tumor tissue, especially from chemotherapy resistant ovarian cancer tissue and resistant OC cells. STUB1 overexpression or PARK7 silencing suppressed cell growth and promoted ferroptosis in PTX-resistant OC cells, which was reversed by HOXB3 overexpression. Mechanistically, STUB1 mediated ubiquitination of HOXB3 to inhibit HOXB3 expression, and HOXB3 promoted the transcription of PARK7 by binding to the promoter region of PARK7. Furthermore, STUB1 overexpression or PARK7 silencing suppressed tumor formation in nude mice. In short, STUB1 promoted ferroptosis through regulating HOXB3/PARK7 axis, thereby suppressing chemotherapy resistance in OC.

Knockdown of Inhibin Beta A Reversed the Epithelial Growth Factor Receptor Tyrosine Kinase Inhibitor Resistance and Enhanced the Therapeutic Effect of Radiotherapy in Non-Small Cell Lung Cancer.

Lung cancer is a malignant tumor with the highest mortality rate worldwide. Non-small cell lung cancer (NSCLC) accounts for approximately half of all lung cancer cases. Inhibin beta A (INHBA) is a ligand of the transforming growth factor-beta superfamily. This study aimed to analyze the function of INHBA in NSCLC resistance cells. Gene Expression Omnibus and The Cancer Genome Atlas databases were used to identify differentially expressed genes (DEGs) in NSCLC resistance cells and patients. DEGs were further analyzed by gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis. A colony formation assay was performed to determine cell growth. Cell migration and invasion were tested by Transwell assay. Epithelial-mesenchymal transition (EMT)-related genes were analyzed using qRT-PCR and Western blot analysis. Using bioinformatics tools, INHBA was demonstrated to be overexpressed in NSCLC resistant cells and patients. Gefitinib treatment affected NSCLC resistant cells. Additionally, INHBA silencing or X-ray treatment suppressed the growth and metastasis of NSCLC resistant cells. Moreover, the combined application of INHBA silencing and X-ray treatment enhances the therapeutic effects. Moreover, EMT has been confirmed to occur in NSCLC resistant cell lines. Both INHBA silencing and X-ray treatment inhibited EMT development. This study demonstrated that INHBA silencing ameliorates EGFR-TKI resistance and enhances the therapeutic effect of radiotherapy in NSCLC.

USP3 promotes DNA damage response and chemotherapy resistance through stabilizing and deubiquitinating SMARCA5 in prostate cancer.

The chromatin-remodeling enzyme SMARCA5 plays a key role in DNA-templated events including transcription, DNA replication, and DNA repair. Loss of function of the SMARCA5 can cause neurodevelopmental disorder and Williams syndrome. However, the molecular mechanism underlying the regulation of SMARCA5 in prostate cancer remains largely elusive. Here, we report that the deubiquitinating enzyme USP3 directly interacts with SMARCA5 and removes K63-linked polyubiquitination of SMARCA5 to maintain its stability, which promotes DNA damage repair and chemotherapy resistance. Depletion of USP3 or SMARCA5 promoted PCa cells sensitive to docetaxel and overexpression of USP3 restored the cells resistance to docetaxel treatment in SMARCA5 silenced cells in vitro and vivo. Clinically, USP3 was significantly up-regulated in prostate cancer tissues and positively associated with SMARCA5 expression. Collectively, our findings uncover a novel molecular mechanism for the USP3-SMARCA5 axis in regulating DSB repair with an important role in chemotherapy response in human prostate cancers, highlighting that targeting USP3-SMARCA5 axis could be a valuable strategy to treat USP3/SMARCA5-overexpressing chemotherapy-resistant patients and improve drug treatment.

IGF2BP3-dependent N6-methyladenosine modification of USP49 promotes carboplatin resistance in retinoblastoma by enhancing autophagy via regulating the stabilization of SIRT1.

Retinoblastoma (RB) poses significant challenges in clinical management due to the emergence of resistance to conventional chemotherapeutic agents, particularly carboplatin (CBP). In this study, we investigated the molecular mechanisms underlying CBP resistance in RB, with a focus on the role of autophagy and the influence of ubiquitin-specific peptidase 49 (USP49). We observed upregulation of USP49 in RB tissues and cell lines, correlating with disease progression. Functional assays revealed that USP49 promoted aggressive proliferation and conferred CBP resistance in RB cells. Furthermore, USP49 accelerated tumor growth and induced CBP resistance in vivo. Mechanistically, we found that USP49 facilitated CBP resistance by promoting autophagy activation. In addition, we identified insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3)-mediated N6-methyladenosine (m6A) modification of USP49 as a regulatory mechanism, wherein IGF2BP3 upregulated USP49 expression in an m6A-dependent manner. Moreover, USP49 stabilized SIRT1, a protein associated with CBP resistance and autophagy, by inhibiting its ubiquitination and degradation. Rescue experiments confirmed the pivotal role of SIRT1 in USP49-mediated CBP resistance. Our findings delineate a novel molecular network involving USP49-mediated autophagy in promoting CBP resistance in RB, offering potential targets for therapeutic intervention to enhance treatment efficacy and improve outcomes for RB patients.

YAP regulates HER3 signaling-driven adaptive resistance to RET inhibitors in RET-aberrant cancer.

Rearranged during transfection (RET) aberrations represent a targetable oncogene in several tumor types, with RET inhibitors displaying marked efficacy. However, some patients with RET-aberrant cancer are insensitive to RET tyrosine kinase inhibitors (TKIs). Recently, drug-tolerant mechanisms have attracted attention as targets for initial therapies to overcome drug resistance. The underlying mechanisms of drug-tolerant cell emergence treated with RET-TKIs derived from RET-aberrant cancer cells remain unknown. This study investigated the role of YAP-mediated HER3 signaling in the underlying mechanisms of adaptive resistance to RET-TKIs in RET-aberrant cancer cells. Four RET-aberrant cancer cell lines were used to assess sensitivity to the RET-TKIs selpercatinib and pralsetinib and to elucidate molecular mechanisms underlying adaptive resistance using RNA sequencing, phospho-RTK antibody arrays, chromatin immunoprecipitation assay, and luciferase reporter assays. Clinical specimens from patients with RET-fusion-positive lung cancer were analyzed for pre-treatment YAP expression and correlated with treatment outcomes. In high YAP-expressing RET-aberrant cancer cells, YAP-mediated HER3 signaling activation maintained cell survival and induced the emergence of cells tolerant to the RET-TKIs selpercatinib and pralsetinib. The pan-ErBB inhibitor afatinib and YAP/TEAD inhibitors verteporfin and K-975 sensitized YAP-expressing RET-aberrant cancer cells to the RET-TKIs selpercatinib and pralsetinib. Pre-treatment YAP expression in clinical specimens obtained from patients with RET-fusion-positive lung cancer was associated with poor RET-TKI treatment outcomes. The YAP-HER3 axis is crucial for the survival and adaptive resistance of high YAP-expressing RET-aberrant cancer cells treated with RET-TKIs. Combining YAP/HER3 inhibition with RET-TKIs represents a highly potent strategy for initial treatment.

Knockout of Caspase-1 Disrupts Pyroptosis and Protects Photoreceptor Cells from Photochemical Damage

Retinal photochemical damage (RPD) plays a significant role in the development of various ocular diseases, with Caspase-1 being a key contributor. This study investigates the protective effects of Caspase-1 gene-mediated pyroptosis against RPD. Differentially expressed genes (DEGs) associated with RPD were identified through the analysis of two expression profiles from the GEO database. Correlation analysis was used to pinpoint pyroptosis-related genes (PRGs) linked to RPD. A Caspase-1 knockout 661W cell line was generated via CRISPR-Cas9 gene editing, and single-cell colonies were screened and purified. Validation of knockout cells was performed through RT-qPCR, gene sequencing, and Western blot analysis. Comparative assays on cell proliferation, intracellular reactive oxygen species (ROS), and cytotoxicity were conducted between wild-type and Caspase-1 knockout cells under light exposure. Further RT-qPCR and Western blot experiments examined changes in the mRNA and protein levels of key pyroptosis pathway components. Significant alterations in Caspase-1 expression were observed among PRGs. Homozygous Caspase-1 knockout cell lines were confirmed through RT-qPCR, genomic PCR product sequencing, and Western blot analysis. Compared to wild-type 661W cells, Caspase-1 knockout cells exhibited higher viability and proliferation rates after 24 hours of light exposure, alongside reduced LDH release. The expression of downstream pyroptosis factors at both the mRNA and protein levels was markedly decreased in the knockout group. CRISPR/Cas9-mediated Caspase-1 knockout enhanced the resistance of 661W cells to photochemical damage, suggesting that Caspase-1 may serve as a potential therapeutic target for RPD-related diseases.

The Mechanism of Action of Exosomes Derived from Glioblastoma Cells.

Glioblastoma (GBM) is a highly aggressive and lethal brain tumor characterized by rapid growth, invasive behavior, and resistance to conventional therapies, such as surgery, radiotherapy, and chemotherapy. Despite these interventions, patient survival remains poor due to the tumor's ability to recur and adapt to treatments. The function of GBM-derived exosomes (GBM-exosomes) as essential mediators in tumor growth has drawn attention in recent years. These small extracellular vesicles are involved in the transfer of a variety of molecules, including cytokines, miRNAs, proteins, and DNA, facilitating intercellular communication that promotes GBM cell proliferation, angiogenesis, immune evasion, and resistance to therapies. This review aims to provide an in- -depth examination of the mechanisms through which GBM-exosomes contribute to these pathological processes, as well as to discuss the current methodologies for isolating and characterizing GBM exosomes. Additionally, we explore the potential of exosomes as biomarkers for diagnosis and prognosis and as novel therapeutic targets in the fight against GBM. By improving our understanding of GBM-exosomes, we can pave the way for the development of more effective, personalized treatment strategies that may improve patient outcomes and quality of life.

Targeting the SPC25/RIOK1/MYH9 Axis to Overcome Tumor Stemness and Platinum Resistance in Epithelial Ovarian Cancer.

In epithelial ovarian cancer (EOC), platinum resistance, potentially mediated by cancer stem cells (CSCs), often leads to relapse and treatment failure. Here, the role of spindle pole body component 25 (SPC25) as a key determinant promoting stemness and platinum resistance in EOC cells, with its expression being correlated with adverse clinical outcomes is delineated. Mechanistically, SPC25 acts as a scaffolding platform, orchestrating the assembly of an SPC25/RIOK1/MYH9 trimeric complex, triggering RIOK1-mediated phosphorylation of MYH9 at Ser1943. This prompts MYH9 to disengage from the cytoskeleton, augmenting its nuclear accumulation, thus potentiating CTNNB1 transcription and subsequent activation of Wnt/β-catenin signaling. CBP1, a competitive inhibitory peptide, can disrupt the formation of the aforementioned trimeric complex, diminishing the activity of the SPC25/RIOK1/MYH9 axis-mediated Wnt/β-catenin signaling, and thus attenuate CSC phenotypes, thereby enhancing platinum efficacy in vitro, in vivo, and in patient-derived organoids. Therefore, targeting the SPC25/RIOK1/MYH9 axis, which mediates the maintenance of stemness and platinum resistance in EOC cells, may enhance platinum sensitivity and increase survival in patients with EOC.

Mitotic Arrest Deficient 2 Like 1 Contributes to Colorectal Cancer Cell Migration, Invasion, and Oxaliplatin Resistance Through the Wnt/β-Catenin Pathway.

Colorectal cancer (CRC) is a highly prevalent malignancy, requiring chemotherapy for advanced stages of the disease. Previously, we found that mitotic arrest deficient 2 like 1 (MAD2L1) was upregulated and facilitated malignant proliferation in CRC. However, the association between MAD2L1 expression and tumor progression, as well as chemotherapy resistance in CRC, remains unclear. The progression capacities of CRC cells were assessed using transwell and wound healing assays, and the resistance to cisplatin in oxaliplatin-resistant CRC cells was assessed using CCK-8 assay and flow cytometry. Relevant protein levels of epithelial-to-mesenchymal transition (EMT) and Wnt/β-catenin pathway were analyzed using western blotting. Revealing the impact of MAD2L1 on metastasis and drug resistance in CRC through inhibition of the Wnt/β-catenin pathway. Knockdown of MAD2L1 attenuated the malignant progression of CRC cells, inhibited EMT, and blocked the Wnt/β-catenin pathway. MAD2L1 was significantly upregulated in oxaliplatin-resistant CRC cells, accompanied by the activation of the Wnt/β-catenin pathway. Knockdown of MAD2L1 effectively reversed oxaliplatin resistance, leading to apoptosis and downregulation of the protein expression levels of β-catenin, P-glycoprotein (P-gp), and ABCG2. After the knockdown of MAD2L1, the inhibition of the Wnt/β-catenin pathway exhibited a synergistic effect, effectively suppressing malignant progression and reversing oxaliplatin resistance in CRC cells. So, knockdown of MAD2L1 suppressed cell malignant progression, equally sensitized resistant CRC cells to oxaliplatin, potentially by blocking the activation of the Wnt/β-catenin pathway.

Circ_0006089 facilitates gastric cancer progression and oxaliplatin resistance via miR-217/NRP1

BackgroundOxaliplatin (OXA) is a vital tool in the chemotherapy of gastric cancer (GC) patients. Circular RNAs (circRNAs) are a group of non-coding RNAs that have been associated with tumorigenesis. Nevertheless, the function of circRNAs in OXA resistance of GC is unknown. MethodsCirc_0006089/miR-217/NRP1 were elucidated through qRT-PCR in GC OXA-tolerant tissues and cell lines. OXA half-inhibitory concentration (IC50) was quantified by MTT assay. RNA pull-down and luciferase reporter tests were applied to characterize the interaction between circ_0006089 and miR-217, miR-217 and NRP1 in GC cells. ResultsThe findings disclosed that circ_0006089 and NRP1 was heightened whereas miR-217 was dramatically declined in OXA-tolerant GC tissues and cell lines. OXA resistance was reduced and the proliferation, migration and invasion ability of OXA cells were diminished after silencing circ_0006089. In addition, circ_0006089 raised OXA resistance by sponging miR-217. Further studies revealed that miR-217 bound to NRP1 and weakened OXA resistance. In addition, it was found that circ_0006089 accelerated GC progression and OXA resistance by upregulating NRP1 expression via sponging miR-217. ConclusionCirc_0006089 regulated OXA resistance in GC cells through miR-217/NRP1 axis, implying it was a promising biomarker for GC therapy.

E3 ubiquitin ligase DTX2 fosters ferroptosis resistance via suppressing NCOA4-mediated ferritinophagy in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) remains the foremost contributor to cancer-related fatalities globally, with limited effective therapeutic modalities. Recent research has shed light on the role of ferroptosis in various types of cancers, offering a potential avenue for improving cancer therapy. Herein, we identified E3 ubiquitin ligase deltex 2 (DTX2) as a potential therapeutic target candidate implicated in promoting NSCLC cell growth by inhibiting ferroptosis. Our investigation revealed a significant upregulation of DTX2 in NSCLC cells and tissues, which was correlated with poor prognosis. Downregulation of DTX2 suppressed NSCLC cell growth both in vitro and in vivo, while its overexpression accelerated cell proliferation. Moreover, knockdown of DTX2 promoted ferroptosis in NSCLC cells, which was mitigated by DTX2 overexpression. Mechanistically, we uncovered that DTX2 binds to nuclear receptor coactivator 4 (NCOA4), facilitating its ubiquitination and degradation via the K48 chain, which subsequently dampens NCOA4-driven ferritinophagy and ferroptosis in NSCLC cells. Notably, DTX2 knockdown promotes cisplatin-induced ferroptosis and overcomes drug resistance of NSCLC cells. These findings underscore the critical role of DTX2 in regulating ferroptosis and NCOA4-mediated ferritinophagy, suggesting its potential as a novel therapeutic target for NSCLC.

The engagement of Ras/Raf/MEK/ERK and PLCγ1/PKC pathways regulated by TrkB receptor in resistance of glioma cells to elimination upon apoptosis induction

The engagement of Ras/Raf/MEK/ERK and PLCγ1/PKC pathways regulated by TrkB receptor in resistance of glioma cells to elimination upon apoptosis induction

MiR-195-5p inhibits cisplatin resistance in lung adenocarcinoma by regulating DNA damage via targeting E2F7.

Lung adenocarcinoma (LUAD) emerges as one of the most lethal malignant tumors worldwide. Platinum-based combination chemotherapy remains one of the main methods for patients with advanced LUAD. Due to the resistance, the effect of this chemotherapy was not satisfactory. Therefore, studying the mechanism of cisplatin (DDP) resistance is essential for promoting the effect of this therapeutic strategy. Therefore, this work sought to probe the impact of E2F Transcription Factor 7 (E2F7) on LUAD resistance and the molecular regulatory mechanism. The mRNA expression level of the target gene E2F7 in LUAD was predicted by bioinformatics analysis, and regulatory miRNA upstream of the target gene was identified. The mRNA and protein expression of E2F7 in LUAD cells was detected through quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and Western blot, respectively. The expression of miR-195-5p in LUAD cells was measured via qRT-PCR. E2F7 high and low expression groups underwent enrichment analysis by utilizing Gene Set Enrichment Analysis software. The targeting relationship of miR-195-5p and E2F7 was validated by conducting a dual-luciferase reporter assay. The cell viability was tested through cell counting kit-8. The cell cycle was examined by flow cytometry. DNA damage level was determined via Comet assay and Western blot assay. The findings indicated that the mRNA and protein levels of E2F7 were high in LUAD. MiR-195-5p was the regulatory miRNA upstream of E2F7, and lowly expressed in LUAD. The cell experiments suggested that E2F7 advanced the DDP resistance of LUAD cells by repressing DNA damage. Finally, the rescue assay manifested that miR-195-5p overexpression could abate inhibition of E2F7 overexpression on the DNA damage and the DDP sensitivity of LUAD cells. MiR-195-5p raised the DDP sensitivity of LUAD cells by advancing the DNA damage in LUAD cells via inhibition of E2F7.

Combination of multivalent DR5 receptor clustering agonists and histone deacetylase inhibitors for treatment of colon cancer

Death Receptor 5 (DR5) targeted therapies offer significant promise due to their pivotal role in mediating the extrinsic pathway of apoptosis. Despite DR5 overexpression in various malignancies and the potential of tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), clinical implementations of anti-DR5 monoclonal antibodies (mAbs) have been hampered by suboptimal outcomes potentially due to lack of receptor clustering.To address the limitation, we developed N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer-based conjugates integrating multiple copies of DR5-targeting peptide (cyclic WDCLDNRIGRRQCVKL; cDR5) to enhance receptor clustering and apoptosis. Three conjugates with variable number of cDR5 were prepared and denoted as PH-cDR5 (high valence), PM-cDR5 (medium valence) and PL-cDR5 (low valence). Our studies in TRAIL-sensitive and resistant cancer cell lines demonstrated that the HPMA copolymer-peptide conjugates (P-cDR5) significantly improved DR5 receptor clustering and induced apoptosis effectively. In TRAIL-sensitive colon cancer cells (COLO205, HCT-116), P-cDR5 showed efficacy comparable to anti-DR5 mAb Drozitumab (DRO), but P-cDR5 outperformed DRO in TRAIL-resistant cells (HT-29), highlighting the importance of efficient receptor clustering. In COLO205 cells PM-cDR5 exhibited an IC50 of 94 pM, while PH-cDR5 had an even lower IC50 of 15 pM (based on cDR5 equivalent concentration), indicating enhanced potency of the multivalent HPMA copolymer-based system with a flexible polymer backbone in comparison with the IC50 for TRAIL at 0.12 nM. Combining P-cDR5 with valproic acid, a histone deacetylase inhibitor, resulted in further enhancement of apoptosis inducing efficacy, along with destabilizing mitochondrial membranes and increased sensitivity of TRAIL-resistant cells. These findings suggest that attaching multiple cDR5 peptides to a flexible water-soluble polymer carrier not only overcomes the limitations of previous designs but also offers a promising avenue for treating resistant cancers, pointing toward the need for further preclinical exploration and validation of this innovative strategy.

A Gene Expression Signature that Predicts Gastric Cancer Sensitivity to PARP Inhibitor Therapy.

Biomarkers indicating sensitivity to poly ADP-ribose polymerase (PARP) inhibitors have not yet been identified in gastric cancer. PARP inhibitors target homologous recombination deficiency (HRD); however, homologous recombination (HR) induces complex changes in gene expression, which makes it difficult to identify reliable biomarkers. In this study, we identified a multi-gene expression signature as a marker of PARP inhibitor sensitivity in gastric cancer. Seven gastric cancer cell lines were evaluated for susceptibility to PARP inhibitors using a growth inhibition assay. Gene expression profiling (GEP) was used to identify differentially expressed genes between PARP inhibitor-sensitive and -resistant cell lines. The resulting gene set was subjected to cluster analysis using tumor samples from 250 patients who underwent gastrectomy for primary gastroesophageal junction and gastric adenocarcinoma. HRD was defined as a truncating mutation in one or more of 22 HR-related genes and HRD scores were calculated using whole-exome sequencing data. In the growth inhibition assays, the HGC27 and HSC39 cell lines were sensitive to the PARP inhibitors, olaparib, and rucaparib, and were significantly correlated with the GEP results. Seven (2.8%) patients harbored truncating mutations in HR-related genes. A gene expression signature based on the top 100 high and low differentially expressed genes between sensitive and resistant cell lines revealed a patient cluster with a high prevalence of HR-related gene mutations and high HRD scores. The 100-gene expression signature identified in this study may serve as a valuable predictive biomarker for PARP inhibitor sensitivity in gastric cancer.