Cisplatin-resistant Patients Research Articles

Refractory testicular germ cell tumors are highly sensitive to the targeting of polycomb pathway demethylases KDM6A and KDM6B

Testicular germ cell tumors (TGCTs) can be treated with cisplatin-based therapy. However, a clinically significant number of cisplatin-resistant patients die from progressive disease as no effective alternatives exist. Curative cisplatin therapy results in acute and life-long toxicities in the young TGCT patient population providing a rationale to decrease cisplatin exposure. In contrast to genetic alterations, recent evidence suggests that epigenetics is a major driving factor for TGCT formation, progression, and response to chemotherapy. Hence, targeting epigenetic pathways with “epidrugs” is one potential relatively unexplored strategy to advance TGCT treatment beyond cisplatin. In this report, we demonstrate for the first time that targeting polycomb demethylases KDM6A and KDM6B with epidrug GSK-J4 can treat both cisplatin-sensitive and -resistant TGCTs. While GSK-J4 had minimal effects alone on TGCT tumor growth in vivo, it dramatically sensitized cisplatin-sensitive and -resistant TGCTs to cisplatin. We validated KDM6A/KDM6B as the target of GSK-J4 since KDM6A/KDM6B genetic depletion had a similar effect to GSK-J4 on cisplatin-mediated anti-tumor activity and transcriptome alterations. Pharmacologic and genetic targeting of KDM6A/KDM6B potentiated or primed the p53-dominant transcriptional response to cisplatin, with also evidence for basal activation of p53. Further, several chromatin modifier genes, including BRD4, lysine demethylases, chromodomain helicase DNA binding proteins, and lysine methyltransferases, were repressed with cisplatin only in KDM6A/KDM6B-targeted cells, implying that KDM6A/KDM6B inhibition sets the stage for extensive chromatin remodeling of TGCT cells upon cisplatin treatment. Our findings demonstrate that targeting polycomb demethylases is a new potent pharmacologic strategy for treating cisplatin resistant TGCTs that warrants clinical development.

Refractory testicular germ cell tumors are highly sensitive to the targeting of polycomb pathway demethylases KDM6A and KDM6B.

Testicular germ cell tumors (TGCTs) can be treated with cisplatin-based therapy. However, a clinically significant number of cisplatin-resistant patients die from progressive disease as no effective alternatives exist. Curative cisplatin therapy results in acute and life-long toxicities in the young TGCT patient population providing a rationale to decrease cisplatin exposure. In contrast to genetic alterations, recent evidence suggests that epigenetics is a major driving factor for TGCT formation, progression, and response to chemotherapy. Hence, targeting epigenetic pathways with "epidrugs" is one potential relatively unexplored strategy to advance TGCT treatment beyond cisplatin. In this report, we demonstrate for the first time that targeting polycomb demethylases KDM6A and KDM6B with epidrug GSK-J4 can treat both cisplatin-sensitive and -resistant TGCTs. While GSK-J4 had minimal effects alone on TGCT tumor growth in vivo, it dramatically sensitized cisplatin-sensitive and -resistant TGCTs to cisplatin. We validated KDM6A/KDM6B as the target of GSK-J4 since KDM6A/KDM6B genetic depletion had a similar effect to GSK-J4 on cisplatin-mediated anti-tumor activity and transcriptome alterations. Pharmacologic and genetic targeting of KDM6A/KDM6B potentiated or primed the p53-dominant transcriptional response to cisplatin, with also evidence for basal activation of p53. Further, several chromatin modifier genes, including BRD4, lysine demethylases, chromodomain helicase DNA binding proteins, and lysine methyltransferases, were repressed with cisplatin only in KDM6A/KDM6B-targeted cells, implying that KDM6A/KDM6B inhibition sets the stage for extensive chromatin remodeling of TGCT cells upon cisplatin treatment. Our findings demonstrate that targeting polycomb demethylases is a new potent pharmacologic strategy for treating cisplatin resistant TGCTs that warrants clinical development.

MicroRNA-486-3p affects cisplatin resistance in high-grade serous ovarian cancer by regulating TMIGD2: An experimental study

Ovarian cancer represents a major public health concern worldwide. High-grade serous ovarian cancer (HGSOC) is a primary epithelial ovarian cancer. Cisplatin resistance poses a substantial obstacle in the management of HGSOC, leading to unfavourable patient outcomes. The primary objective of this study was to investigate the mechanisms underlying cisplatin resistance in patients with HGSOC. TCGA data, GSE65819 dataset, and multiMiR package were used to identify 35 differentially expressed miRNAs (DE-miRNAs). Differentially expressed mRNAs (DE-mRNAs) are indicated using TCGA data. Further, weighted gene co-expression network analysis (WGCNA) was used to determine the correlation coefficients between the DE-mRNAs and DE-miRNAs. A network of miR-486-3p and TMIGD2 was constructed. Molecular biology experiments also indicated that low miR-486-3p or high TMIGD2 expression significantly increased the migratory rate and cisplatin resistance of both SK-OV3 and A2780 cells. In contrast, overexpression of miR-486-3p or downregulation of TMIGD2 decreased the migration rate and enhanced the sensitivity to cisplatin treatment, which provides insights for the development of novel therapeutic approaches. Moreover, RNA-binding protein immunoprecipitation experiment was used to determine the relationship between miR-486-3p and TMIGD2. Cell rescue assays were performed to further investigate these regulatory relationships. In TCGA and GSE65819 datasets, Benjamini and Hochberg false discovery rates (FDR) were selected for P-values. In the molecular biology experiments, one-way analysis of variance was employed to compare different groups, supplemented by Bonferroni post-hoc testing. Statistical significance was set at p < 0.05.

The role and mechanism of IFITM1 in developing acquired cisplatin resistance in small cell lung cancer

Platinum-based chemotherapies, historically the cornerstone of first-line treatment for small-cell lung cancer (SCLC), face a major hurdle: the frequent emergence of chemoresistance, notably to cisplatin (CDDP). Current understanding of the mechanisms driving CDDP resistance in SCLC is incomplete. Notably, Interferon inducible transmembrane protein1 (IFITM1) has been identified as a key player in the distant metastasis of SCLC. Analysis of The Cancer Genome Atlas (TCGA) database revealed that IFITM1 expression is markedly elevated in tumor tissues as compared to that from adjacent normal tissues, correlating with a worse prognosis for patients with SCLC. Our research focused on investigating the role of IFITM1 in the acquisition of cisplatin resistance in SCLC. Further clinical sample analysis highlighted a significant increase in IFITM1 levels in SCLC tissues from cisplatin-resistant patients versus those were responsive to CCDP treatment, with similar trends observed in cisplatin-resistant SCLC cells. Crucially, overexpression of IFITM1 reduced the sensitivity of SCLC cells to cisplatin, while silencing IFITM1 enhanced chemosensitivity in cisplatin-resistant strains. Our in vivo studies further confirmed that silencing IFITM1 significantly boosted the efficacy of cisplatin in inhibiting growth of subcutaneous tumors of NCI–H466/CDDP cells (cisplatin-resistant SCLC cells) in a mouse model. Mechanistically, IFITM1 appears to foster cisplatin resistance through activation of the Wnt/β-catenin pathway. In summary, our findings suggest that targeting IFITM1, alongside cisplatin treatment, could offer a promising therapeutic strategy to overcome resistance and improve outcomes for SCLC patients.

Reversal of cisplatin resistance in oral squamous cell carcinoma by piperlongumine loaded smart nanoparticles through inhibition of Hippo-YAP signaling pathway

Cisplatin alone or in combination with 5FU and docetaxel is the preferred chemotherapy regimen for advanced-stage OSCC patients. However, its use has been linked to recurrence and metastasis due to the development of drug resistance. Therefore, sensitization of cancer cells to conventional chemotherapeutics can be an effective strategy to overcome drug resistance. Piperlongumine (PL), an alkaloid, have shown anticancer properties and sensitizes numerous neoplasms, but its effect on OSCC has not been explored. However, low aqueous solubility and poor pharmacokinetics limit its clinical application. Therefore, to improve its therapeutic efficacy, we developed piperlongumine-loaded PLGA-based smart nanoparticles (smart PL-NPs) that can rapidly release PL in an acidic environment of cancer cells and provide optimum drug concentrations to overcome chemoresistance. Our results revealed that smart PL-NPs has high cellular uptake in acidic environment, facilitating the intracellular delivery of PL and sensitizing cancer cells to cisplatin, resulting in synergistic anticancer activity in vitro by increasing DNA damage, apoptosis, and inhibiting drug efflux. Further, we have mechanistically explored the Hippo-YAP signaling pathway, which is the critical mediator of chemoresistance, and investigated the chemosensitizing effect of PL in OSCC. We observed that PL alone and in combination with cisplatin significantly inhibits the activation of YAP and its downstream target genes and proteins. In addition, the combination of cisplatin with smart PL-NPs significantly inhibited tumor growth in two preclinical models (patient-derived cell based nude mice and zebrafish xenograft). Taken together, our findings suggest that smart PL-NPs with cisplatin will be a novel formulation to reverse cisplatin resistance in patients with advanced OSCC.

Deubiquitinase USP7 stabilizes KDM5B and promotes tumor progression and cisplatin resistance in nasopharyngeal carcinoma through the ZBTB16/TOP2A axis

Cisplatin-based chemotherapy improves the control of distant metastases in patients with nasopharyngeal carcinoma (NPC); however, around 30% of patients fail treatment due to acquired drug resistance. Epigenetic regulation is known to contribute to cisplatin resistance; nevertheless, the underlying mechanisms remain poorly understood. Here, we showed that lysine-specific demethylase 5B (KDM5B) was overexpressed and correlates with tumor progression and cisplatin resistance in patients with NPC. We also showed that specific inhibition of KDM5B impaired the progression of NPC and reverses cisplatin resistance, both in vitro and in vivo. Moreover, we found that KDM5B inhibited the expression of ZBTB16 by directly reducing H3K4me3 at the ZBTB16 promoter, which subsequently increased the expression of Topoisomerase II- α (TOP2A) to confer cisplatin resistance in NPC. In addition, we showed that the deubiquitinase USP7 was critical for deubiquitinating and stabilizing KDM5B. More importantly, the deletion of USP7 increased sensitivity to cisplatin by disrupting the stability of KDM5B in NPC cells. Therefore, our findings demonstrated that USP7 stabilized KDM5B and promoted cisplatin resistance through the ZBTB16/TOP2A axis, suggesting that targeting KDM5B may be a promising cisplatin-sensitization strategy in the treatment of NPC.

Abstract B091: Overexpression of Muscleblind Like Splicing Regulator 2 (MBNL2) enhances cisplatin resistance in ovarian cancer

Abstract Ovarian cancer is the second most commonly diagnosed gynecological cancer and has the highest mortality rate of all gynecological cancers worldwide. Although cisplatin is one of the most effective antitumor drugs for ovarian cancer, the emergence of chemoresistance to cisplatin is a major barrier to successful therapy. To identify epigenetically regulated genes directly associated with ovarian cancer cisplatin resistance, we compared the expression and methylation profiles of cisplatin-sensitive and -resistant human ovarian cancer cell lines. We identified Muscleblind Like Splicing Regulator 2 (MBNL2) as one of the key candidate genes for cisplatin drug response. Interestingly, in cisplatin-resistant cell lines, MBNL2 mRNA expression was significantly upregulated, and the MBNL2 promoter was associated with hypomethylation of the specific cytosine-phosphate-guanine (CpG) sites. Reduced MBNL2 expression in cisplatin-sensitive cell lines was restored by treatment with a DNA demethylation agent, suggesting epigenetic regulation of MBNL2 expression by promoter methylation. Furthermore, depletion of MBNL2 in cisplatin-resistant cells induced cytotoxicity in response to cisplatin, whereas overexpression of MBNL2 in cisplatin-sensitive cells increased chemoresistance, indicating that MBNL2 plays a vital role in developing chemoresistance in ovarian cancer cells. Furthermore, we performed meta-analysis using fourteen publicly available datasets to assess the association between expression of MBNL2 and overall survival in patients with serous-type ovarian cancer. The pooled Hazard ratios (HRs) estimate was significantly greater than 1 for overall survival (HR=1.09, p-value=0.0034). The association was more significant (HR=1.12, p-value=0.001) when tumor stage was added to the survival analysis as a covariate. The meta-analysis revealed that high expression of MBNL2 was significantly associated with poor prognosis and a higher risk of death in ovarian cancer patients with serous tumor. Additionally, we further validated the MBNL2 mRNA expression in primary ovarian tumor tissues. The statistically significant upregulation of MBNL2 mRNA expression was observed in cisplatin-resistant patients compared to that of cisplatin-sensitive patients. Our findings suggest MBNL2 may be a potential therapeutic target for the prevention of chemoresistance to cisplatin in ovarian cancer. Citation Format: Woong Ju, Hye Youn Sung, Jung-Hyuck Ahn. Overexpression of Muscleblind Like Splicing Regulator 2 (MBNL2) enhances cisplatin resistance in ovarian cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr B091.

In vitro assay identifying cisplatin resistance of head and neck squamous cell carcinoma

• Demonstrate patient tumor slice organoid (PTSO) as an in vitro rapid platform in identifying cisplatin-resistant patients. • Water soluble tetrazolium salt (WST-8) assay was used a viability test for determining cisplatin-resistance. • Cisplatin-resistance data obtained within 5 days after the initiation of PTSO culture. • Report cisplatin-resistance of a male 43 years with recurrent tongue cancer as validated from the patient's survival periods.

Characteristics of Extracellular Vesicles from a High-Grade Serous Ovarian Cancer Cell Line Derived from a Platinum-Resistant Patient as a Potential Tool for Aiding the Prediction of Responses to Chemotherapy.

Platinum-resistant high-grade serous ovarian cancer (HGSOC) is invariably a fatal disease. A central goal of ovarian cancer research is therefore to develop new strategies to overcome platinum resistance. Treatment is thus moving towards personalized therapy. However, validated molecular biomarkers that predict patients' risk of developing platinum resistance are still lacking. Extracellular vesicles (EVs) are promising candidate biomarkers. EpCAM-specific EVs are largely unexplored biomarkers for predicting chemoresistance. Using transmission electron microscopy, nanoparticle tracking analysis and flow cytometry, we compared the characteristics of EVs released from a cell line derived from a clinically confirmed cisplatin-resistant patient (OAW28) and EVs released from two cell lines from tumors sensitive to platinum-based chemotherapy (PEO1 and OAW42). We demonstrated that EVs released from the HGSOC cell line of chemoresistant patients exhibited greater size heterogeneity, a larger proportion of medium/large (>200 nm) Evs and a higher number of released EpCAM-positive EVs of different sizes, although the expression of EpCAM was predominant in EVs larger than 400 nm. We also found a strong positive correlation between the concentration of EpCAM-positive EVs and the expression of cellular EpCAM. These results may contribute to the prediction of platinum resistance in the future, although they should first be validated in clinical samples.

Reversal of Cisplatin Resistance in Ovarian Cancer by the Multitargeted Nanodrug Delivery System Tf-Mn-MOF@Nira@CDDP.

Cisplatin (CDDP) is a widely used chemotherapeutic drug with proven efficacy for treating tumors. However, its use has been associated with severe side effects and eventually leads to drug resistance, thus limiting its clinical application in patients with ovarian cancer (OC). Herein, we aimed to investigate the success rate of reversing cisplatin resistance using a synthetic, multitargeted nanodrug delivery system comprising a Mn-based metal-organic framework (Mn-MOF) containing niraparib (Nira) and CDDP alongside transferrin (Tf) conjugated to the surface (Tf-Mn-MOF@Nira@CDDP; MNCT). Our results revealed that MNCT can target the tumor site, consume glutathione (GSH), which is highly expressed in drug-resistant cells, and then decompose to release the encapsulated Nira and CDDP. Nira and CDDP play a synergistic role in increasing DNA damage and apoptosis, exhibiting excellent antiproliferation, migration, and invasion activities. In addition, MNCT significantly inhibited tumor growth in tumor-bearing mice and exhibited excellent biocompatibility without side effects. Furthermore, it depleted GSH, downregulated multidrug-resistant transporter protein (MDR) expression, and upregulated tumor suppressor protein phosphatase and tensin homolog (PTEN) expression, consequently reducing DNA damage repair and reversing cisplatin resistance. These results indicate that multitargeted nanodrug delivery systems can provide a promising clinical approach to overcoming cisplatin resistance. This study provides an experimental basis for further investigation into multitargeted nanodrug delivery systems to reverse cisplatin resistance in patients with OC.

Identification of a novel PARP4 gene promoter CpG locus associated with cisplatin chemoresistance

The protein family of poly (ADP-ribose) polymerases (PARPs) is comprised of multifunctional nuclear enzymes. Several PARP inhibitors have been developed as new anticancer drugs to combat resistance to chemotherapy. Herein, we characterized PARP4 mRNA expression profiles in cisplatin-sensitive and cisplatin-resistant ovarian cancer cell lines. PARP4 mRNA expression was significantly upregulated in cisplatin-resistant ovarian cancer cell lines, and this upregulation was associated with hypomethylation of specific cytosine-phosphate-guanine (CpG) sites (cg18582260 and cg17117459) on its promoter. Reduced PARP4 expression was restored by treating cisplatin-sensitive cell lines with a demethylation agent, implicating epigenetic regulation of PARP4 expression by promoter methylation. Depletion of PARP4 expression in cisplatin-resistant cell lines reduced cisplatin chemoresistance and promoted cisplatin-induced DNA fragmentation. The differential mRNA expression and DNA methylation status at specific PARP4 promoter CpG sites (cg18582260 and cg17117459) according to cisplatin responses, were further validated in primary ovarian tumor tissues. The results showed significantly increased PARP4 mRNA expressions and decreased DNA methylation levels at specific PARP4 promoter CpG sites (cg18582260 and cg17117459) in cisplatin-resistant patients. Additionally, the DNA methylation status at cg18582260 CpG sites in ovarian tumor tissues showed fairly clear discrimination between cisplatin-resistant patients and cisplatin-sensitive patients, with high accuracy (area under the curve = 0.86, p = 0.003845). Our findings suggested that the DNA methylation status of PARP4 at the specific promoter site (cg18582260) may be a useful diagnostic biomarker for predicting the response to cisplatin in ovarian cancer patients.

Combinatorial Treatment with PARP-1 Inhibitors and Cisplatin Attenuates Cervical Cancer Growth through Fos-Driven Changes in Gene Expression.

Our observations, which link the gene regulatory effects of PARPi + cisplatin to the growth inhibitory effects of FOS expression in cervical cancer cells, strengthen the rationale for using PARPi with cisplatin as a therapy for cervical cancer.

PD53-05 BLADDER CANCER TUMOROIDS AND NORMAL UROTHELIAL ORGANOIDS AS NEAR-PATIENT MODELS TO STUDY BLADDER CANCER TUMORIGENESIS AND PREDICT TREATMENT RESPONSE

You have accessJournal of UrologyCME1 May 2022PD53-05 BLADDER CANCER TUMOROIDS AND NORMAL UROTHELIAL ORGANOIDS AS NEAR-PATIENT MODELS TO STUDY BLADDER CANCER TUMORIGENESIS AND PREDICT TREATMENT RESPONSE Maryam Akbarzadeh, Mathijs Scholtes, Ameneh Bazrafshan, Tokameh Mahmoudi, and Tahlita Zuiverloon Maryam AkbarzadehMaryam Akbarzadeh More articles by this author , Mathijs ScholtesMathijs Scholtes More articles by this author , Ameneh BazrafshanAmeneh Bazrafshan More articles by this author , Tokameh MahmoudiTokameh Mahmoudi More articles by this author , and Tahlita ZuiverloonTahlita Zuiverloon More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002630.05AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Clinical outcome linked to bladder cancer (BC) stage, grade and histology can be attributed to distinct molecular profiles and a better understanding of these molecular profiles could lead to novel rational treatment strategies. We previously successfully set-up a BC tumoroid and urothelial organoid culture protocol to investigate the biological role of molecular alterations in BC. Here, the aim was to characterize previously established patient-derived tumoroids and normal organoids generated from BC patients with various clinical and molecular background. Additionally, we aimed to investigate whether patient-derived tumoroids can serve as a predictive model to guide patient treatment. METHODS: Tumoroid/organoid cultures and originating tissue were characterized by H&E staining, SNaPshot analysis for hTERT, FGFR3 and PIK3CA hotspot mutations, and copy number aberrations (CNA) analysis using SNP-microarrays. Expression of urothelial differentiation markers was investigated by immunofluorescence (CK5, CK20, GATA3) and qPCR (CD44, CK14, GATA3, FOXA1, UPK3A) in tumoroids/organoids treated with different culture conditions. Originating tissues were characterized by immunohistochemistry (CK5, CK14, GATA3, CK20). Tumoroid ex vivo drug response to cisplatin and FGFR-inhibitor erdafitinib treatment was investigated by AlamarBlue and CellTiter-Glo cell viability assays. RESULTS: Tumor-tumoroid pairs showed corresponding hotspot mutations, CNAs, and similar expression of basal/luminal differentiation markers. In case of divergent differentiation or variant histological subtypes, the tumoroid phenotypically resembled the tissue of origin. Tumoroids generated from cisplatin-resistant patients demonstrated resistance to serum concentrations of cisplatin, while FGFR3-mutant tumoroids responded to erdafitinib treatment. As for organoids, no genetic aberrations were detected in originating normal urothelium and organoids did not acquire CNAs or hotspot mutations over freeze-thaw cycles or several months of ex vivo culturing. The organoids could be differentiated to recapitulate the normal urothelial microanatomy showing lumen formation and spatial organization of luminal/basal cells. CONCLUSIONS: We successfully characterized genetically stable BC tumoroid and urothelial organoid lines that molecularly resemble originating tissues. Additionally, we demonstrated that tumoroids can be used to investigate ex vivo treatment response. Source of Funding: Erasmus MC mRACE Grant and TKI-LSH Match Grant © 2022 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 207Issue Supplement 5May 2022Page: e911 Advertisement Copyright & Permissions© 2022 by American Urological Association Education and Research, Inc.MetricsAuthor Information Maryam Akbarzadeh More articles by this author Mathijs Scholtes More articles by this author Ameneh Bazrafshan More articles by this author Tokameh Mahmoudi More articles by this author Tahlita Zuiverloon More articles by this author Expand All Advertisement PDF DownloadLoading ...

NDC80 Enhances Cisplatin-resistance in Triple-negative Breast Cancer

Chemotherapy is a standard systemic treatment option for triple-negative breast cancer (TNBC). Cisplatin has been used to treat TNBC, but frequently leads to cisplatin resistance in patients. The aim of our study was to investigate cisplatin-resistant mechanism in TNBC. To identify the potential genes and pathways relative to cisplatin resistance, GSE103115 data were analyzed by the Limma package and Gene set enrichment analysis (GSEA). TNBC data from TCGA, GSE76250 and GSE115275 datasets were used to calculate NDC80 expression. Immunohistochemistry detected NDC80 protein expression in TNBC tissues from patients before and after cisplatin treatment. After expose to cisplatin treatment, the viability and proliferation of TNBC cells were measured by CCK-8 and colony formation assays, respectively. NDC80 was regarded as a cisplatin-resistant gene because after cisplatin treatment NDC80 was downregulated in cisplatin-sensitive cells but was upregulated in cisplatin-resistant cells. NDC80 was over-expressed in TNBC tissues compared to normal tissues. Furthermore, NDC80 expression in TNBC patients was increased after cisplatin treatment. Cisplatin-sensitive TNBC patients showed lower NDC80 expression than cisplatin-resistant patients. Additionally, NDC80 expression was correlated with clinical stages, tumor size and chemotherapy of TNBC patients. Moreover, NDC80 overexpression promoted the viability and proliferation of TNBC cells and enhanced the cells resistance to cisplatin. The potential pathways relative to cisplatin resistance were obtained, such as p53 signaling pathway and Oxidative phosphorylation. These findings provide new insights for understanding the mechanism of cisplatin resistance in TNBC, and NDC80 may be a potential therapeutic target for TNBC treatment.

Long Non-Coding RNA- PVT1 in Ovarian Cancer as Predictors for Platinum Analogues Resistance

Abstract Background Ovarian cancer is the fifth most common type of cancer and the most common cause of death among women with gynecological malignancies. Objectives The aim of this retrospective study was to assess expression of the Lnc_PVT1 in the studied subjects. The expression of Lnc_PVT1 biomarker; was compared in ovarian cancer patients versus the non-cancerous tissue. The data normalization was tested by normality test which shows that the biomarker expression is not normally distributed; thus, a Mann Whitney statistics test for non -parametric values was applied. Our results showed a high significant difference in the expression of Lnc-PVT1 (p &amp;lt; 0.01). Lnc_PVT1 expression is upregulated by 2.4 folds in ovarian cancer patients (median: 32.0; range: 11 – 92) compared to control group (median: 13.0; range: 11 – 16). Methods and Materials This is a retrospective study. Include patients with advanced epithelial ovarian cancer (stage II and IV) who received chemotherapy platinum based and taxines from 2014-2017. Setting: Clinical oncology department Ain Shams University, Egypt, Demerdash hospital. Data collection: The following information will be ANONYMOUSLY extracted from the patient medical files: age at diagnosis, presenting symptoms, laboratory investigations: (Liver function, kidney function, complete blood count &amp;tumor markers), tumor histological type, tumor FIGO stage&amp; degree of differentiation, treatment modalities, type of surgery, chemotherapy regimens (Adjuvant, Neoadjuvant or palliative), chemotherapy responsiveness or resistance, disease recurrence and disease-free period, and patients' survival. Results The current study was enrolled on 55 subjects, they classified into two subgroups. The ovarian cancer cases constitute 45 patients; samples collected from patients after diagnosis has been confirmed by histopathology based on immune-histochemical analysis as well as Computerized axial tomography (CT scan) and Magnetic resonance imaging (MRI). The cancer ovary patients were compared to ten non- malignant ovarian tissues. Table 1 illustrates the demographic and clinical data of the studied subjects. We test the normality for age; the data was normally distributed. For this reason, we represent the data in mean value and standard deviation form. Matched age and gender was observed between ovarian cancer patients and healthy control. The mean age for the studied subjects was 47.7±9.1. In our study; the Cisplatin resistant patients (n = 25) had a mean age of 46±5 compared to Cisplatin sensitive which were older (mean: 50 ±11.5). Regarding the age subgroups; the majority of the studied subjects were younger than 48 years old. The ovarian cancer patients were subcategorized into subgroups (Cisplatin sensitive/resistant). Conclusion Comparative analysis between Cisplatin sensitive and resistant ovarian cancer tissues for the Lnc_PVT1, TGF-b and Caspase-3. A high significant difference was observed by Mann- Whitney test (p = 0.001) between Cisplatin sensitive and resistant ovarian cancer patients; Cisplatin resistant tissues showed higher expression levels of the Lnc_PVT1 expression (median 20.0, range: 10 - 92) in Cisplatin sensitive ovarian tissue compared to Cisplatin resistant tissue (median: 83; range: 46-86).

Cancer-associated fibroblasts induce monocytic myeloid-derived suppressor cell generation via IL-6/exosomal miR-21-activated STAT3 signaling to promote cisplatin resistance in esophageal squamous cell carcinoma.

Drug resistance remains the major obstacle limiting the effectiveness of chemotherapy for esophageal squamous cell carcinoma (ESCC)[1]. However, how stromal cells cooperate with immune cells to contribute to drug resistance is not yet fully understood. In this study, we observed that monocytic myeloid-derived suppressor cells (M-MDSCs) were correlated with cisplatin resistance in patients with ESCC. Furthermore, CAFs promoted differentiation of monocytes into M-MDSCs phenotypically and functionally in vitro. Mechanically, both interleukin (IL)-6 and exosome-packed microRNA-21 (miR-21) secreted by CAFs synergistically promoted the generation of M-MDSCs via activating the signal transducing activator of transcription 3 (STAT3) by IL-6 in an autocrine manner. Combined blocking of IL-6 receptor and inhibition of miR-21 significantly reversed CAF-mediated M-MDSC generation. Notably, the effects of CAFs on M-MDSC induction were abolished by inhibiting STAT3 signaling. Functionally, CAF-induced M-MDSCs promoted drug resistance of tumor cells upon cisplatin treatment. Clinically, ESCC patients with high infiltration of CAFs and CD11b+ myeloid cells had unfavorable predicted overall survival both in our cohort and in TCGA data. Taken together, our study reveals a paracrine and autocrine of IL-6 caused by CAFs co-activate STAT3 signaling, promoting the generation of M-MDSCs, and highlights the important role of CAFs in cooperation with M-MDSCs in promoting drug resistance, thus providing potential opportunities for reversing drug resistance through inhibition of STAT3 signaling.

C-reactive protein promotes tongue squamous cell carcinoma chemoresistance by inhibiting the activation of caspase-3/9 via the CD64/AKT/mTOR pathway.

Recent studies have shown that C-reactive protein (CRP) participates in multiple types of cancer development. Here, the aim of this study was to investigate the role of CRP in tongue squamous cell carcinoma (TSCC) chemoresistance. Immunohistochemical staining showed that CRP expression was upregulated in TSCC tissues from cisplatin-resistant patients compared with that in cisplatin-sensitive TSCC samples. The CRP expression level was positively correlated with that of the drug-resistant marker MDR1. Moreover, functional experiments showed that CRP increased cell viability and decreased cisplatin-induced apoptosis. CRP also increased the expression levels of MDR1 and Bcl-2 and decreased the expression level of Bax. Furthermore, CRP decreased the activity of caspase-3. Mechanistically, CRP could bind to Fcγ receptor I (FcγRI, also known as CD64) and activate the AKT/mTOR pathway to inhibit the activation of caspase-3/9, as shown by co-immunoprecipitation (Co-IP) assay and western blotting assays. In addition, CRP promoted tumour growth and decreased cleaved caspase-3/9 expression in BALB/c nude mice. Taken together, our findings indicate that CRP promotes TSCC chemoresistance by inhibiting the activation of caspase-3/9 via the FcγRI/AKT/mTOR pathway. Thus, CRP could potentially be considered as a therapeutic target for reducing TSCC chemoresistance.

NEAT1 Overexpression Indicates a Poor Prognosis and Induces Chemotherapy Resistance via the miR-491-5p/SOX3 Signaling Pathway in Ovarian Cancer.

BackgroundAccumulated studies have reported that dysregulated long non-coding RNAs (lncRNAs) are crucial in ovarian cancer (OC) initiation and development. However, detailed biological functions of lncRNA NEAT1 during the progression of OC remains to be uncovered.PurposeOur aim was to identify the role of NEAT1 in cisplatin resistance of ovarian cancer and the underlying mechanisms.MethodsThe expression patterns of NEAT1 in OC cell lines and tissue samples were identified by qRT-PCR. The cisplatin (DDP) sensitivity of OC cells was detected by MTT and CCK8 assay, while OC cell apoptosis and cell cycle were detected using flow cytometer assays. In addition, effects of NEAT1 on tumor growth were determined by xenograft tumor model. Luciferase reporter assay was conducted to prove the regulatory relation of miR-491-5p, NEAT1, and SOX3. Importantly, the expression of NEAT1 in exosomes from cisplatin-resistant patients was also determined by using qRT-PCR.ResultsIn this study, upregulated NEAT1 was detected in OC cell lines and tissues. Meanwhile, NEAT1 was also increased in cisplatin-resistant OC cell lines and tissues. Upregulation of NEAT1 inhibited cisplatin-induced OC cell apoptosis and promoted cell proliferation, while knockdown of NEAT1 played the opposite role. These effects were also observed in vivo. Furthermore, direct interaction was observed between NEAT1 and miR-491-5p. NEAT1 led to the upregulation of miR-491-5p-targeted SOX3 mRNA. Importantly, this study also showed upregulated NEAT1 expression in serum exosomes derived from cisplatin-resistant patients.ConclusionNEAT1 is vital in the chemoresistance of ovarian cancer through regulating miR-491-5p/SOX3 pathway, showing that NEAT1 might be a potential target for OC resistance treatment.

Regulation of MRE11A by UBQLN4 leads to cisplatin resistance in patients with esophageal squamous cell carcinoma.

Resistance to standard cisplatin‐based chemotherapies leads to worse survival outcomes for patients with esophageal squamous cell carcinoma (ESCC). Therefore, there is an urgent need to understand the aberrant mechanisms driving resistance in ESCC tumors. We hypothesized that ubiquilin‐4 (UBQLN4), a protein that targets ubiquitinated proteins to the proteasome, regulates the expression of Meiotic Recombination 11 Homolog A (MRE11A), a critical component of the MRN complex and DNA damage repair pathways. Initially, immunohistochemistry analysis was conducted in specimens from patients with ESCC (n = 120). In endoscopic core ESCC biopsies taken from 61 patients who underwent neoadjuvant chemotherapy (NAC) (5‐fluorouracil and cisplatin), low MRE11A and high UBQLN4 protein levels were associated with reduced pathological response to NAC (P < 0.001 and P < 0.001, respectively). Multivariable analysis of surgically resected ESCC tissues from 59 patients revealed low MRE11A and high UBLQN4 expression as independent factors that can predict shorter overall survival [P = 0.01, hazard ratio (HR) = 5.11, 95% confidence interval (CI), 1.45–18.03; P = 0.02, HR = 3.74, 95% CI, 1.19–11.76, respectively]. Suppression of MRE11A expression was associated with cisplatin resistance in ESCC cell lines. Additionally, MRE11A was found to be ubiquitinated after cisplatin treatment. We observed an amplification of UBQLN4 gene copy numbers and an increase in UBQLN4 protein levels in ESCC tissues. Binding of UBQLN4 to ubiquitinated‐MRE11A increased MRE11A degradation, thereby regulating MRE11A protein levels following DNA damage and promoting cisplatin resistance. In summary, MRE11A and UBQLN4 protein levels can serve as predictors for NAC response and as prognostic markers in ESCC patients.

Roles of E3 ubiquitin ligases in gastric cancer carcinogenesis and their effects on cisplatin resistance.

Although gastric cancer (GC) is one of the most common cancers with high incidence and mortality rates, its pathogenesis is still not elucidated. GC carcinogenesis is complicated and involved in the activation of oncoproteins and inactivation of tumor suppressors. The ubiquitin-proteasome system (UPS) is crucial for protein degradation and regulation of physiological and pathological processes. E3 ubiquitin ligases are pivotal enzymes in UPS, containing various subfamily proteins. Previous studies report that some E3 ligases, including SKP2, CUL1, and MDM2, act as oncoproteins in GC carcinogenesis. On the other hand, FBXW7, FBXL5, FBXO31, RNF43, and RNF180 exert as tumor suppressors in GC carcinogenesis. Moreover, E3 ligases modulate cell growth, cell apoptosis, and cell cycle; thus, it is complicated to confer cisplatin resistance/sensitivity in GC cells. The intrinsic and acquired cisplatin resistance limits its clinical application against GC. In this review, we explore oncogenic and tumor suppressive roles of E3 ligases in GC carcinogenesis and focus on the effects of E3 ligases on cisplatin resistance in GC cells, which will provide novel therapeutic targets for GC therapy, especially for cisplatin-resistant patients.