Chemotherapy-resistant Cancer Research Articles

Multi-omics analysis reveals the role of the autophagy-related gene AGT in chemotherapy resistance in colorectal cancer and the therapeutic potential of its inhibitors

Multi-omics analysis reveals the role of the autophagy-related gene AGT in chemotherapy resistance in colorectal cancer and the therapeutic potential of its inhibitors

The Role of Ribonucleotide Reductase M2 in Lung Cancer Progression and Chemotherapy Resistance: A Bioinformatics Analysis and Review.

The Role of Ribonucleotide Reductase M2 in Lung Cancer Progression and Chemotherapy Resistance: A Bioinformatics Analysis and Review.

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.

Inhibition of K+ Channels Affects the Target Cell Killing Potential of CAR T Cells

Ion channels of T cells (Kv1.3, KCa3.1, and CRAC) participate in the regulation of activation and effector functions via modulation of the Ca2+-dependent pathway. T cells expressing chimeric antigen receptors (CAR T cells) showed a remarkable role in anti-tumor therapy, especially in the treatment of chemotherapy-resistant liquid cancers. Nevertheless, many challenges remain to be overcome to improve the treatment for solid tumors. In this study, we assessed the expression and role of ion channels in CAR T cells. We found that HER2-specific CAR T cells had higher KCa3.1 conductance compared to the non-transduced (NT, control) cells, which was more prominent in the CD8+ population (CD4+ cell also showed elevation). Conversely, the Kv1.3 expression level was the same for all cell types (CD4+, CD8+, CAR, and NT). Single-cell Ca2+ imaging revealed that thapsigargin-induced SOCE via CRAC is suppressed in CD8+ CAR T cells, unlike for CD4+ and CD8+ NT cells. To dissect the functional role of Kv1.3 and KCa3.1, we used specific antagonists (Kv1.3: Vm24; KCa3.1: TRAM-34): the target cell elimination capacity of the CD8+ CAR T cells was improved either by blocking KCa3.1 or Kv1.3. These results imply that ion channels could be a target in CAR T cell immunotherapy elaboration.

Artificial synthetic gene circuits for dynamic monitoring and feedback intervention of chemotherapy resistance in bladder cancer

Artificial synthetic gene circuits for dynamic monitoring and feedback intervention of chemotherapy resistance in bladder cancer

All-trans retinoic acid-mediated ADAR1 degradation synergizes with PD-1 blockade to suppress pancreatic cancer.

As a double-stranded RNA-editing enzyme and an interferon-stimulated gene, double-stranded RNA-specific adenosine deaminase (ADAR1) suppresses interferon signaling and contributes to immunotherapy resistance. Suppression of ADAR1 overcomes immunotherapy resistance in preclinical models, but has not yet been translated to clinical settings. By conducting a screening of a subset of the FDA-approved drugs, we found that all-trans retinoic acid (ATRA, also known as tretinoin) caused ADAR1 protein degradation through ubiquitin-proteasome pathways and concomitantly increased PD-L1 expression in pancreatic and breast cancers. In addition, the combination of ATRA and PD-1 blockade reprogrammed the tumor microenvironment and unleashed antitumor immunity and thereby impeded tumor growth in pancreatic cancer mouse models. In a pilot clinical trial, a higher dose of ATRA plus the anti-PD-1 antibody nivolumab prolonged median overall survival in patients with chemotherapy-resistant pancreatic cancer compared to a lower dose of the same regimen. In this study, ATRA was the first drug to be found to cause ADAR1 degradation. We propose translation of a promising 2-pronged antitumor strategy using ATRA and nivolumab to convert immunologically "cold" into "hot" tumors susceptible to immune checkpoint blockade.

The Impact and Mechanism of Action of Peptostreptococcus anaerobius on Chemotherapy Resistance in Human Colorectal Cancer.

Peptostreptococcus anaerobius plays an important role in the development of colorectal cancer, and previous studies by our group have demonstrated that Peptostreptococcus anaerobius promotes resistance to 5-Fu chemotherapy in animal models of colorectal cancer. In this study, the effects of Peptostreptococcus anaerobius on chemotherapy resistance in colorectal cancer and its possible mechanism of action were investigated from the clinical point of view. Patients were selected according to exclusion and inclusion criteria and divided into sensitive and chemotherapy groups (n = 20/group). Fecal samples were collected from the patients. The bacterial 16S rRNA genes in the samples were sequenced and the abundance and varieties in the fecal bacteria were compared between the 2 groups. Immunohistochemistry and Western blotting were used to assess interleukin 23 levels in tumor tissues. Significantly elevated abundance of Peptostreptococcus was observed in fecal samples from chemoresistant colorectal cancer patients compared to those from chemosensitive individuals. Immunohistochemistry and Western blotting results showed that chemoresistant patients had higher levels of interleukin 23 relative to chemosensitive patients and the levels were positively associated with Peptostreptococcus. Peptostreptococcus may mediate the development of chemoresistant colorectal cancer by promoting the upregulation of interleukin 23. Efforts to target Peptostreptococcus thus have the potential to alter the prognosis of colorectal cancer patients.

Tumor-associated macrophages/C-X-C motif chemokine ligand 1 promotes breast cancer autophagy-mediated chemoresistance via IGF1R/STAT3/HMGB1 signaling

Autophagy-mediated chemoresistance is the core mechanism for therapeutic failure and poor prognosis in breast cancer. Breast cancer chemotherapy resistance is believed to be influenced by tumor-associated macrophages (TAMs), by which C-X-C motif chemokine ligand 1 (CXCL1) is the most abundant cytokine secreted. Yet, its role in mediating autophagy-related chemoresistance is still unknown. This study aimed to explore the molecular mechanisms by which TAMs/CXCL1 induced autophagy-mediated chemoresistance in breast cancer. It was found that TAMs/CXCL1 promoted chemoresistance of breast cancer cells through autophagy activation in vitro, and CXCL1 silence could enhance the chemosensitivity of paclitaxel-resistant breast cancer cells via autophagy inhibition. A high-throughput quantitative PCR chip and subsequent target validation showed that CXCL1 induced autophagy-mediated chemoresistance by inhibiting VHL-mediated IGF1R ubiquitination. The elevated IGF1R then promoted STAT3/HMGB1 signaling to facilitate autophagy. Additionally, TAMs/CXCL1 silence improved paclitaxel chemosensitivity by suppressing autophagy in breast cancer mice xenografts, and clinical studies further linked CXCL1 to IGF1R/HMGB1 signaling, as well as shorter free survival of recurrence. Taken together, these results not only uncover the crucial role of TAMs/CXCL1 signaling in mediating breast cancer chemoresistance through enhancing autophagy, but also shed novel light on the molecular mechanism of IGF1R/STAT3/HMGB1 pathway in regulating autophagy and its impact on cancer prognosis.

Advances in natural products modulating autophagy influenced by cellular stress conditions and their anticancer roles in the treatment of ovarian cancer.

Autophagy is a conservative catabolic process that typically serves a cell-protective function. Under stress conditions, when the cellular environment becomes unstable, autophagy is activated as an adaptive response for self-protection. Autophagy delivers damaged cellular components to lysosomes for degradation and recycling, thereby providing essential nutrients for cell survival. However, this function of promoting cell survival under stress conditions often leads to malignant progression and chemotherapy resistance in cancer. Consequently, autophagy is considered a potential target for cancer therapy. Herein, we aim to review how natural products act as key modulators of autophagy by regulating cellular stress conditions. We revisit various stressors, including starvation, hypoxia, endoplasmic reticulum stress, and oxidative stress, and their regulatory relationship with autophagy, focusing on recent advances in ovarian cancer research. Additionally, we explore how polyphenolic compounds, flavonoids, alkaloids, terpenoids, and other natural products modulate autophagy mediated by stress responses, affecting the malignant biological behavior of cancer. Furthermore, we discuss their roles in ovarian cancer therapy. This review emphasizes the importance of natural products as valuable resources in cancer therapeutics, highlighting the need for further exploration of their potential in regulating autophagy. Moreover, it provides novel insights and potential therapeutic strategies in ovarian cancer by utilizing natural products to modulate autophagy.

Resistance to the platinum‑based chemotherapeutic drugs in oral cancer: Focus on the role of p22phox (Review).

Oral cancer, commonly known as oral squamous cell carcinoma (OSCC), is an aggressive malignancy in the oral cavity with a poor prognosis and survival rate, particularly at the advanced stages. Oral cancer represents one of the most widespread cancers worldwide, in which the prevalence is particularly high in South and Southeast Asia. While the incidence and mortality rates continue to increase over the past decades, oral cancer treatment can be challenging and at times ineffective, largely due to drug resistance. To date, platinum-based drugs, such as cisplatin, remain the mainstay of chemotherapy for patients with oral cancer. However, long-term exposure to cisplatin inevitably leads to the development of resistance to the drug, which is still a major issue to overcome in oral cancer treatment. The molecular mechanisms of cisplatin resistance in oral cancer have been extensively studied in recent years and the present review places specific emphasis on a novel mechanism of resistance to the platinum drugs mediated by p22phox, an endoplasmic reticulum membrane protein. In addition to delineating the unique p22phox-dependent cisplatin resistance, the present review compares and contrasts the resistance mechanism to its current counterparts. Finally, with the goal of tackling the problem of chemotherapy resistance in oral cancer, various strategies are presented that may counteract p22phox-dependent cisplatin resistance, which may potentially improve the efficacy of the platinum-based drugs and warrant future clinical validation.

Serial single-cell RNA sequencing unveils drug resistance and metastatic traits in stage IV breast cancer

Metastasis is a complex process that remains poorly understood at the molecular levels. We profiled single-cell transcriptomic, genomic, and epigenomic changes associated with cancer cell progression, chemotherapy resistance, and metastasis from a Stage IV breast cancer patient. Pretreatment- and posttreatment-specimens from the primary tumor and distant metastases were collected for single-cell RNA sequencing and subsequent cell clustering, copy number variation (CNV) estimation, transcriptomic factor estimation, and pseudotime analyses. CNV analysis revealed that a small population of pretreatment cancer cells resisted chemotherapy and expanded. New clones including Metastatic Precursor Cells (MPCs), emerged in the posttreatment primary tumors in CNV similar to metastatic cells. MPCs exhibited expression profiles indicative of epithelial–mesenchymal transition. Comparison of MPCs with metastatic cancer cells also revealed dynamic changes in transcription factors and calcitonin pathway gene expression. These findings demonstrate the utility of single-patient clinical sample analysis for understanding tumor drug resistance, regrowth, and metastasis.

Intrinsic temperature increase drives lipid metabolism towards ferroptosis evasion and chemotherapy resistance in pancreatic cancer

A spontaneously occurring temperature increase in solid tumors has been reported sporadically, but is largely overlooked in terms of cancer biology. Here we show that temperature is increased in tumors of patients with pancreatic ductal adenocarcinoma (PDAC) and explore how this could affect therapy response. By mimicking this observation in PDAC cell lines, we demonstrate that through adaptive changes in lipid metabolism, the temperature increase found in human PDAC confers protection to lipid peroxidation and contributes to gemcitabine resistance. Consistent with the recently uncovered role of p38 MAPK in ferroptotic cell death, we find that the reduction in lipid peroxidation potential following adaptation to tumoral temperature allows for p38 MAPK inhibition, conferring chemoresistance. As an increase in tumoral temperature is observed in several other tumor types, our findings warrant taking tumoral temperature into account in subsequent studies related to ferroptosis and therapy resistance. More broadly, our findings indicate that tumoral temperature affects cancer biology.

Delivery of doxorubicin by Fe3O4 nanoparticles, reduces multidrug resistance gene expression in ovarian cancer cells

BackgroundOvarian cancer is one of the most common malignancy in women with significant mortality rate due to the resistance to chemotherapy drugs. Doxorubicin (DOX) is a chemotropic agent in ovarian cancer treatment. Overexpression of multidrug resistance (MDR) genes, such as ABCB1, in cancer cells after chemotherapy is one of main problems in clinical applications. Here we have compared the efficiency of doxorubicin-loaded (NIPAAM-DMAEMA) Fe3O4 nanocomposite (DOX-NANO) against DOX on ABCB1(MDR1) gene expression in the ovarian cancer cell line. Materials and MethodsThe cell viability of SKOV-3 cells were evaluated by MTT assay. Real Time PCR was used to measure the expression level of MDR1. MTT data were normalized in 10 different attribute weighting models, also to reveal the interaction between DOX, ABCB1, and ovarian cancer genes, Pathway Studio Database (Elsevier) was used. ResultsCell viability of SKOV-3cells was significantly decreased after 24, 48 and 72hours (P < 0.0001) of either DOX with IC50 22.38, 0.61 and 0.072µg/ml or DOX-NANO treatment with IC50 11.54, 1.01, 0.0126µg/ ml respectively. treatment. Notable decrease in the expression of MDR gene, ABCB1, was observed 48hours after treatment with DOX-NANO (P < 0.0001) with 26% in the assessed with control group. Meta-analysis showed the concentration of 10μg/ml variables was the second most significant feature, whereas the concentration of 0.01μg/ml recognized the lowest weights. Also, LGALS3 is an extra cellular receptor with upregulation in ovarian cancer that interacts with ABCB1. ConclusionOur findings highlight the beneficial effects of DOX delivery in ovarian cancer cells by nanocomposite as efficient drug delivery method. DOX-NANO is a promising therapeutic reagent to overcome chemotherapy resistance in ovarian cancer.

Targeting the Epidermal Growth Factor Receptor Pathway in Chemotherapy-Resistant Triple-Negative Breast Cancer: A Phase II Study.

Epidermal growth factor receptor (EGFR) pathway activation causes chemotherapy resistance, and inhibition of the EGFR pathway sensitizes triple-negative breast cancer (TNBC) cells to chemotherapy in preclinical models. Given the high prevalence of EGFR overexpression in TNBC, we conducted a single-arm phase II study of panitumumab (anti-EGFR monoclonal antibody), carboplatin, and paclitaxel as the second phase of neoadjuvant therapy (NAT) in patients with doxorubicin and cyclophosphamide (AC)-resistant TNBC (NCT02593175). Patients with early-stage, AC-resistant TNBC, defined as disease progression or ≤80% reduction in tumor volume after four cycles of AC, were eligible for this study and received panitumumab (2.5 mg/kg i.v., every week × 13), paclitaxel (80 mg/m2 i.v. every week × 12), and carboplatin (AUC = 4 i.v., every 3 weeks × 4) as the second phase of NAT. A two-stage Gehan-type design was used to detect an improvement in the pathological complete response (pCR)/residual cancer burden class I (RCB-I) rate from 5% to 20%. Whole-exome sequencing was performed on diagnostic tumor biospecimens, where available. From November 3, 2016, through August 23, 2021, 43 patients with AC-resistant TNBC were enrolled. The combined pCR/RCB-I rate was 30.2%. The most common treatment-related adverse events were neutropenia (72%) and anemia (61%), with 7 (16%), 16 (37%), and 8 (19%) patients experiencing grade 4 neutropenia, grade 3 neutropenia, and grade 3 anemia, respectively. No new safety signals were observed. This study met its primary endpoint (pCR/RCB-I = 30.2% vs. 5% in historical controls), suggesting that panitumumab should be evaluated as a component of NAT in patients with chemotherapy-resistant TNBC in a larger, randomized clinical trial. The epidermal growth factor receptor (EGFR) pathway has been implicated as a driver of chemotherapy resistance in triple-negative breast cancer (TNBC). Here, we evaluate the combination of panitumumab, carboplatin, and paclitaxel as the second phase of neoadjuvant therapy (NAT) in patients with AC-resistant TNBC. This study met its primary efficacy endpoint, and molecular alterations in EGFR pathway genes did not seem to influence response to the study regimen.

The up-regulation of PAK2 indicates unfavorable prognosis in patients with serous epithelial ovarian cancer and contributes to paclitaxel resistance in ovarian cancer cells

BackgroundThe main challenge in treating ovarian cancer is chemotherapy resistance. Previous studies have shown that PAK2 is highly expressed in various cancers. This research investigates whether increased PAK2 expression contributes to chemo-resistance and poor prognosis in ovarian cancer.MethodsInitially, bioinformatics analysis was used to assess the importance of PAK2 mRNA up-regulation in ovarian cancer. This was then validated using tissue microarray to confirm PAK2 protein expression and localization in clinical samples. Univariate and multivariate logistic regression analyses were carried out to identify potential risk factors for chemo-resistance in serous epithelial ovarian cancer (EOC), while multivariate Cox regression and Kaplan-Meier analysis were conducted to ascertain prognostic factors for overall survival (OS) and disease-free survival (DFS) in patients with serous EOC. In vitro experiments were conducted to verify if inhibiting PAK2 expression could increase A2780/Taxol cells’ sensitivity to paclitaxel, as shown by evaluating cell proliferation, apoptosis, transwell, and clone formation. Additionally, the interaction between PAK2, lnc-SNHG1, and miR-216b-5p was verified using RIP and luciferase reporter assays. Rescue experiments were undertaken to examine the influence of the lnc-SNHG1/miR-216b-5p/PAK2 axis on the development of paclitaxel resistance in A2780/Taxol cells.ResultsThe bioinformatics analysis indicated a notable increase in PAK2 expression in ovarian malignant tumors compared to adjacent tissues, particularly in patients with stage III-IV disease compared to those with stage I-II disease (P = 0.0056). Elevated levels of PAK2 were linked to reduced OS in ovarian cancer patients, although no significant association was observed with DFS. Immunohistochemistry findings further supported these results, showing positive PAK2 protein expression in chemo-resistant serous EOC tissues, predominantly localized in the cytoplasm, which correlated with poorer OS and DFS outcomes. In vitro experiments demonstrated that the downregulation of PAK2 in A2780/Taxol cells led to a reduction in colony formation, an increase in apoptosis, and a diminished capacity for cell invasion. Subsequent analysis confirmed that lnc-SNHG1 functions as a competitive endogenous RNA (ceRNA) by interacting with miR-216b-5p and regulating PAK2 expression. Rescue experiments demonstrated that lnc-SNHG1 induces resistance to paclitaxel in A2780/Taxol cells by modulating the miR-216b-5p/PAK2 axis.ConclusionsPAK2 shows promise as a predictor of chemotherapy resistance and poor outcomes in ovarian cancer, indicating its potential use as a treatment target to overcome this resistance.

TRF-Leu reverse breast cancer cells chemoresistance by regulation of BIRC5

ObjectiveAccumulating studies reported the crucial roles of tRFs in tumorigenesis. However, their further mechanisms and clinical values remains unclear. This study aimed at the further investigation of tRF-Leu in breast cancer chemotherapy resistance.MethodsThe high-throughput sequencing was performed and identified the downregulation of tRF-Leu in MCF7/ADR cells. The function of tRF-Leu in breast cancer cells and breast cancer chemotherapy resistance was investigated in vitro and in vivo, including colony formation assay, CCK-8 assay, transwell assay and apoptosis assay. The binding site of tRF-Leu on BIRC5 was verified by dual-luciferase assay.ResultstRF-Leu was downregulated in MCF7/ADR cells. Overexpression of tRF-Leu inhibited the migration of breast cancer cells. Furthermore, tRF-Leu could reverse the resistance of MCF7/ADR cells to Adriamycin both in vitro and in vivo. BIRC5 was a target of tRF-Leu, which might be involved in the chemotherapy resistance regulation.ConclusionWe demonstrated that tRF-Leu could inhibit the chemotherapy resistance of breast cancer by targeting BIRC5. These findings might identify new biomarkers of breast cancer therapy and bring new strategies to reverse chemotherapy resistance.

Immune escape between endoplasmic reticulum stress-related cancer cells and exhausted CD8+T cells leads to neoadjuvant chemotherapy resistance in ovarian cancer

Our study aims to explore the effects of neoadjuvant chemotherapy (NACT) on tumour cells and immune cells in the immune microenvironment of patients with high-grade serous ovarian cancer (HGSOC).Single-cell RNA sequencing data of paired ovarian cancer tissues were analysed before and after NACT in 11 patients with HGSOC. The effect of NACT on two major cell components of the tumour microenvironment, epithelial cells and CD8+T cells, was investigated. The mechanisms of epithelial cell evasion by NACT and immune killing were explored from the perspectives of gene expression, functional characteristics, transcriptional regulation, and cell communication. Key targets for reversing NACT resistance were identified and possible therapeutic strategies proposed.While NACT improved the de novo differentiation of anti-tumour CD8+T cells, enhancing their anti-tumour function, it increased the proportion of cancer cells with high HSP90B1 expression. Thus, the potential reasons for NACT resistance were identified as: 1) high levels of endoplasmic reticulum stress (ERS) characteristics, 2) high expression of the MDK-NCL ligand-receptor pair between them and exhausted CD8+T cells before NACT, and 3) high expression of the NECTIN2-TIGIT immune ligand-receptor pair between them and exhausted CD8+T cells after NACT.Thus, our study reveals the mechanisms underlying NACT resistance in patients with HGSOC from the perspective of the independent and interactive roles of cancer cells and CD8+T cells. We propose therapeutic strategies targeting the ERS marker HSP90B1 and the immune escape marker MDK before or during NACT, while targeting NECTIN2 blockade after NACT. This approach may offer new insights into combination treatments for patients with HGSOC displaying NACT resistance.

CRLF1 bridges AKT and mTORC2 through SIN1 to inhibit pyroptosis and enhance chemo-resistance in ovarian cancer

Ovarian cancer, the second most leading cause of gynecologic cancer mortality worldwide, is challenged by chemotherapy resistance, presenting a significant hurdle. Pyroptosis, an inflammation-linked programmed cell death mediated by gasdermins, has been shown to impact chemoresistance when dysregulated. However, the mechanisms connecting pyroptosis to chemotherapy resistance in ovarian cancer are unclear. We found that cytokine receptor-like factor 1 (CRLF1) is a novel component of mTORC2, enhancing AKT Ser473 phosphorylation through strengthening the interaction between AKT and stress-activated protein kinase interacting protein 1 (SIN1), which in turn inhibits the mitogen-activated protein kinase kinase kinase 5 (ASK1)-JNK-caspase-3-gasdermin E pyroptotic pathway and ultimately confers chemoresistance. High CRLF1-expressing tumors showed sensitivity to AKT inhibition but tolerance to cisplatin. Remarkably, overexpression of binding-defective CRLF1 variants impaired AKT-SIN1 interaction, promoting pyroptosis and chemosensitization. Thus, CRLF1 critically regulates chemoresistance in ovarian cancer by modulating AKT/SIN1-dependent pyroptosis. Binding-defective CRLF1 variants could be developed as tumor-specific polypeptide drugs to enhance chemotherapy for ovarian cancer.

Promising effect of cisplatin and melatonin combination on the inhibition of cisplatin resistance in ovarian cancer

Background Ovarian cancer management has not yet given a satisfactory result, and the recurrence rate is still high. One of the reasons for this is resistance to chemotherapy. Melatonin and cisplatin may be involved in the chemotherapy resistance of ovarian cancer. Methods A laboratory experiment was performed using melatonin and cisplatin in the SKOV3 cell, from September 2020 to November 2021 at the SCTE and Integrated Laboratory &amp; Research Center Universitas Indonesia. Several variables were used, such as doxorubicin, melatonin, cisplatin, and combination of cisplatin and melatonin at several concentrations (1×, 3/4×, 1/2×, and 1/4×). A total of 24 samples were included and divided into 8 groups. The IC50 values of melatonin, doxorubicin, and cisplatin as well as cell viability was calculated via MTS assay. Subsequently, flow cytometry was performed to assess the effect of cisplatin and melatonin on the mechanisms of CTR1, p-glycoprotein, GSH, ERCC1, e-cadherin, and apoptosis. Analysis of variance and Bonferroni test were employed for the study. Results The IC50 values of melatonin, cisplatin, and doxorubicin were 1.841 mM, 117.5 mM, and 14.72 mM, respectively. The combination groups of cisplatin and melatonin reduced cell viability; decreased the CTR1 mean (19.73), Pgp (6.7), GSH (11.73), and ERCC1 (4.27) in the combination 1 (C1) group; and increased e-cadherin (32.2) and annexin V (53.57) also in the combination 1 (C1) group. Conclusions The combination of melatonin and cisplatin might have an impact on drug resistance via several mechanisms in ovarian cancer.

Integrated bioinformatics analysis and validation identify KIR2DL4 as a novel biomarker for predicting chemotherapy resistance and prognosis in colorectal cancer

BackgroundChemotherapy and immunotherapy have improved the cure rate and survival period for colorectal cancer (CRC), but genetic heterogeneity among patients leads to chemotherapy resistance and disease progression. Identifying new molecular markers is crucial for improving prognosis for CRC patients. KIR2DL4, a transmembrane glycoprotein expressed by immune cells, has shown potential therapeutic and prognostic value in other cancers, but in CRC remains unclear. MethodsThis study validated the expression levels of KIR2DL4 in CRC by integrating multiple public databases and assessed through immunohistochemistry (IHC). We further evaluated the diagnostic and prognostic value of KIR2DL4 and explored correlation with immune cell infiltration and chemotherapy sensitivity. The role of KIR2DL4 was further validated through functional enrichment analysis. Cellular assays were conducted using CCK8, colony-formation assay and scratch wound assay. ResultsThe study found that KIR2DL4 is significantly downregulated in CRC and closely associated with poor prognosis. The low expression of KIR2DL4 is associated with decreased immune cell infiltration and reduced chemotherapy sensitivity. Functional enrichment analysis suggests that KIR2DL4 may inhibit development of CRC by affecting immune cell infiltration and modulating chemotherapy sensitivity. Cellular assays have confirmed that inhibiting KIR2DL4 significantly promotes the proliferation and migration of CRC. Inhibition of KIR2DL4 expression significantly decreased the chemosensitivity of CRC cells to oxaliplatin and 5-FU. ConclusionThe significant downregulation of KIR2DL4 in CRC, associated with CRC metastasis and poor prognosis, highlights its importance as a potential new biomarker for treatment and prognosis assessment of CRC. Future research should delve into the molecular mechanisms of KIR2DL4 and potential applications in regulating immunotherapy and chemotherapy sensitivity.