Role of Metastasis-Related Genes in Cisplatin Chemoresistance in Gastric Cancer

Recent Advances on Pt-Based Compounds for Theranostic Applications

Since the discovery of cisplatin's antitumoral activity and its approval as an anticancer drug, significant efforts have been made to enhance its physiological stability and anticancer efficacy and to reduce its side effects. With the rapid development of targeted and personalized therapies, and the promising theranostic approach, platinum drugs have found new opportunities in more sophisticated systems. Theranostic agents combine diagnostic and therapeutic moieties in one scaffold, enabling simultaneous disease monitoring, therapy delivery, response tracking, and treatment efficacy evaluation. In these systems, the platinum core serves as the therapeutic agent, while the functionalized ligand provides diagnostic tools using various imaging techniques. This review aims to highlight the significant role of platinum-based complexes in theranostic applications, and, to the best of our knowledge, this is the first focused contribution on this type of platinum compounds. This review presents a brief introduction to the development of platinum chemotherapeutic drugs, their limitations, and resistance mechanisms. It then describes recent advancements in integrating platinum complexes with diagnostic agents for both tumor treatment and monitoring. The main body is organized into three categories based on imaging techniques: fluorescence, positron emission tomography (PET), single-photon emission computed tomography (SPECT), and magnetic resonance imaging (MRI). Finally, this review outlines promising strategies and future perspectives in this evolving field.

Identification of protein biomarkers for prediction of response to platinum-based treatment regimens in patients with non-small cell lung cancer

The majority of patients with resected stage II-IIIA non-small cell lung cancer (NSCLC) are treated with platinum-based adjuvant chemotherapy (ACT) in a one-size-fits-all approach. However, a significant number of patients do not derive clinical benefit, and no predictive patient selection biomarker is currently available. Using mass spectrometry-based proteomics, we have profiled tumour resection material of 2 independent, multi-centre cohorts of in total 67 patients with NSCLC who underwent ACT. Unsupervised cluster analysis of both cohorts revealed a poor response/survival sub-cluster composed of ~ 25% of the patients, that displayed a strong epithelial-mesenchymal transition signature and stromal phenotype. Beyond this stromal sub-population, we identified and validated platinum response prediction biomarker candidates involved in pathways relevant to the mechanism of action of platinum drugs, such as DNA damage repair, as well as less anticipated processes such as those related to the regulation of actin cytoskeleton. Integration with pre-clinical proteomics data supported a role for several of these candidate proteins in platinum response prediction. Validation of one of the candidates (HMGB1) in a third independent patient cohort using immunohistochemistry highlights the potential of translating these proteomics results to clinical practice.

Multiple functions of HMGB1 in cancer

High mobility group box 1 (HMGB1) is a nuclear DNA-binding protein with a dual role in cancer, acting as an oncogene and a tumor suppressor. This protein regulates nucleosomal structure, DNA damage repair, and genomic stability within the cell, while also playing a role in immune cell functions. This review comprehensively evaluates the biological and clinical significance of HMGB1 in cancer, including its involvement in cell death and survival, its potential as a therapeutic target and cancer biomarker, and as a prosurvival signal for the remaining cells after exposure to cytotoxic anticancer treatments. We highlight the need for a better understanding of the cellular markers and mechanisms involved in the involvement of HMGB1in cancer, and aim to provide a deeper understanding of its role in cancer progression.

Tanshinone I Stimulates Pyroptosis of Cisplatin-Resistant Gastric Cancer Cells by Activating the NF-κB/Caspase-3(8)/GSDME Signaling Pathway

Cisplatin (DDP) resistance frequently occurs in gastric cancer (GC) therapy. Tanshinone I is a liposoluble phenanthraquinone compound present in the roots of Salvia miltiorrhiza Bunge (Danshen). In this study, we aimed to explore the effects of tanshinone I on modulating DDP resistance of GC cells in vitro and in vivo. DDP-resistant GC cell models (BGC823/DDP and SGC7901/DDP) were established, and their viability, proliferation, migration, lactate dehydrogenase activity, reactive oxygen species (ROS) generation, and pyroptosis were assessed after DDP treatment with or without tanshinone I. In addition, a mouse model with subcutaneously transplanted GC tumors was established to confirm the effects of tanshinone I and DDP on tumor growth and cell pyroptosis. The results revealed that tanshinone I inhibited DDP-resistant GC cell proliferation and migration; increased intracellular ROS levels; and activated cell pyroptosis by enhancing the levels of cleaved caspase-8, cleaved caspase-3, GSDME-NT, phospho-IKK-α/β, and nuclear factor kappa-B (NF-κB). GSDME knockdown weakened these effects of tanshinone I on DDP-resistant GC cells. Furthermore, DDP combined with tanshinone I inhibited the growth of subcutaneously transplanted GC tumors in mice by reducing cell proliferation and inducing pyroptosis. In conclusion, tanshinone I reversed DDP resistance of GC cells by stimulating pyroptosis, by activating NF-κB/caspase-3(8)/GSDME signaling pathway.

The mechanisms of tanshinone in the treatment of tumors

Tanshinone is a lipophilic compound that is present in traditional Chinese medicine and is derived from the roots of Salvia miltiorrhiza (Danshen). It has been proven to be highly effective in combating tumors in various parts of the body, including liver carcinoma, gastric cancer, ovarian cancer, cervix carcinoma, breast cancer, colon cancer, and prostate cancer. Tanshinone can efficiently prevent the reproduction of cancerous cells, induce cell death, and inhibit the spread of cancerous cells, which are mainly involved in the PI3K/Akt signaling pathway, NF-κB pathway, Bcl-2 family, Caspase cascades, MicroRNA, MAPK signaling pathway, p21, STAT3 pathway, miR30b-P53-PTPN11/SHP2 axis, β-catenin, and Skp2. However, the properties and mechanisms of tanshinone's anti-tumor effects remain unclear currently. Thus, this study aims to review the research progress on tumor prevention and mechanisms of tanshinone to gain new perspectives for further development and clinical application of tanshinone.

Immune perturbation network identifies an EMT subtype with chromosomal instability and tumor immune-desert microenvironment

Most gastric cancer (GC) subtypes are identified through transcriptional profiling overlooking dynamic changes and interactions in gene expression. Based on the background network of global immune genes, we constructed sample-specific edge-perturbation matrices and identified four molecular network subtypes of GC (MNG). MNG-1 displayed the best prognosis and vigorous cell cycle activity. MNG-2 was enriched by immune-hot phenotype with the potential for immunotherapy response. MNG-3 and MNG-4 were identified with epithelial-mesenchymal transition (EMT) peculiarity and worse prognosis, termed EMT subtypes. MNG-3 was characterized by low mutational burden and stromal cells and considered a replica of previous subtypes associated with poor prognosis. Notably, MNG-4 was considered a previously undefined subtype with a dismal prognosis, characterized by chromosomal instability and immune-desert microenvironment. This subtype tended to metastasize and was resistant to respond to immunotherapy. Pharmacogenomics analysis showed three therapeutic agents (NVP-BEZ235, LY2606368, and rutin) were potential interventions for MNG-4.

Two Enhances the Cisplatin Sensitivity of Cervical Cancer Cells via Suppression of c-MET Expression

Background

The drug resistance of chemotherapeutic agents leads to unsatisfactory survival rates for cervical cancer (CC) patients. We aimed to explore the effect of FOXP2 on the sensitivity of CC cells to cisplatin (DDP) and its mechanism in Changde, China in 2018.

Methods

A Total of 6 cervical cancer tissue samples including 3 patients with cisplatin sensitivity and 3 patients with cisplatin resistance, who received DDP-based treatment, were obtained from Changde First People's Hospital, Changde City during 2021, and FOXP2 level was detected by Western blot. The expression levels of FOXP2 and c-MET (hepatocyte growth factor receptor, c-MET) in cells were determined by q-PCR and Western blot analysis. The cell survival, apoptosis, and clone formation were analyzed by flow cytometry, MTT assay, or clone formation assay. Dual-luciferase reporter assays and Chromatin immunoprecipitation were applied to verify the regulation between FOXP2 and c-MET.

Results

FOXP2 was downregulated in cisplatin-resistant cervical cancer tissues and cells compared with control. FOXP2 overexpression in SiHa/DDP cells inhibited cell proliferation and promoted cell apoptosis, whereas down-regulation of FOXP2 in SiHa cells had the opposite result. FOXP2 enhanced chemosensitive to DDP in CC cells. FOXP2 is negatively correlated with c-MET expression level in SiHa and SiHa/DDP cells. Mechanistically, FOXP2 binds to the promoter region of c-MET to regulate its expression in CC cells negatively. Overexpression of c-MET can attenuate the enhancement of DDP-induced apoptosis caused by FOXP2 overexpression.

Conclusion

This is a novel study on the role of FOXP2 in promoting the DDP sensitivity of CC cells by inhibiting c-MET. The FOXP2/c-MET signaling axis uncovered in the present study may be a novel therapeutic target for the DDP therapy resistance of CC.

circUBAP2 inhibits cisplatin resistance in gastric cancer via miR-300/KAT6B axis

Circular RNAs play an important role in regulating cisplatin (CDDP) resistance in gastric cancer (GC). The aim of this study was to examine the role and downstream regulation mechanisms of circUBAP2 in CDDP resistance of GC. The expression of circUBAP2 in GC and its correlation with the prognosis of GC patients were analyzed using qRT-PCR and the Kaplan-Meier plotter database. The effects of circUBAP2 on cell viability and apoptosis were investigated by Cell Counting Kit 8 assay and flow cytometry. The expressions of drug-resistance-related proteins, P-gp and MRP1, were detected by Western blot. The interaction between circUBAP2 and miR-300 was confirmed using RNA pulldown and immunoprecipitation assays. The correlation between miR-300 and KAT6B was assessed using dual-luciferase reporter assay and TCGA database. CircUBAP2 was downregulated in GC tissues and cell lines, and correlated with the poor prognosis of GC. In addition, circUBAP2 enhanced apoptosis but inhibited cell viability and the CDDP resistance of GC cells in vitro . CircUBAP2 acted as a sponge of microRNA-300 (miR-300) and was negatively correlated with miR-300. Moreover, the upregulation of miR-300 partially removed the effects of circUBAP2 on cell viability, apoptosis and CDDP resistance in GC cells. MiR-300 directly targeted to lysine acetyltransferase 6B (KAT6B), and KAT6B overexpression showed an inhibitory effect on cell viability and CDDP resistance of GC cells. Our data suggested that the circUBAP2/miR-300/KAT6B axis was involved in the inhibition of CDDP resistance in GC, which might provide a novel focus for potential GC therapy.

Gemcitabine Resistance in Pancreatic Ductal Carcinoma Cell Lines Stems from Reprogramming of Energy Metabolism

Pancreatic ductal adenocarcinoma (PDAC) is associated with poor prognosis because it is often detected at an advanced stage, and drug resistance interferes with treatment. However, the mechanism underlying drug resistance in PDAC remains unclear. Here, we investigated metabolic changes between a parental PDAC cell line and a gemcitabine (GEM)-resistant PDAC cell line. We established a GEM-resistant cell line, MIA-G, from MIA-PaCa-2 parental (MIA-P) cells using continuous therapeutic-dose GEM treatment. MIA-G cells were also more resistant to 5-fluorouracil in comparison to MIA-P cells. Metabolic flux analysis showed a higher oxygen consumption rate (OCR) in MIA-G cells than in MIA-P cells. Notably, OCR was suppressed by GEM treatment only in MIA-G cells. GEM treatment increased mitochondrial membrane potential and mitochondrial reactive oxygen species (ROS) in MIA-P cells, but not in MIA-G cells. Glutamine uptake and peroxidase levels were elevated in MIA-G cells. The antioxidants N-acetyl-L-cysteine and vitamin C increased the sensitivity to GEM in both cell lines. In MIA-G cells, the expression of the mitochondrial transcription factor A also decreased. Furthermore, rotenone reduced the sensitivity of MIA-P cells to GEM. These findings suggest that the suppression of oxidative phosphorylation contributes to GEM resistance by reducing ROS production. Our study provides a new approach for reducing GEM resistance in PDAC.

Glucosylceramide synthase inhibition protects against cardiac hypertrophy in chronic kidney disease

A significant population of patients with chronic kidney disease (CKD) develops cardiac hypertrophy, which can lead to heart failure and sudden cardiac death. Soluble klotho (sKL), the shed ectodomain of the transmembrane protein klotho, protects the heart against hypertrophic growth. We have shown that sKL protects the heart by regulating the formation and function of lipid rafts by targeting the sialic acid moiety of gangliosides, GM1/GM3. Reduction in circulating sKL contributes to an increased risk of cardiac hypertrophy in mice. sKL replacement therapy has been considered but its use is limited by the inability to mass produce the protein. Therefore, alternative methods to protect the heart are proposed. Glucosylation of ceramide catalyzed by glucosylceramide synthase is the entry step for the formation of gangliosides. Here we show that oral administration of a glucosylceramide synthase inhibitor (GCSi) reduces plasma and heart tissue glycosphingolipids, including gangliosides. Administration of GCSi is protective in two mouse models of cardiac stress-induction, one with isoproterenol overstimulation and the other with 5/6 nephrectomy-induced CKD. Treatment with GCSi does not alter the severity of renal dysfunction and hypertension in CKD. These results provide proof of principle for targeting glucosylceramide synthase to decrease gangliosides as a treatment for cardiac hypertrophy. They also support the hypothesis that sKL protects the heart by targeting gangliosides.

Lucidone inhibits autophagy and MDR1 via HMGB1/RAGE/PI3K/Akt signaling pathway in pancreatic cancer cells

Gemcitabine (GEM) drug resistance remains a difficult challenge in pancreatic ductal adenocarcinoma (PDAC) treatment. Therefore, identifying a safe and effective treatment strategy for PDAC is urgent. Lucidone is a natural compound extracted from the fruits of Lindera erythrocarpa Makino. However, the role of lucidone in PDAC inhibition remains unclear. In addition, high-mobility group box 1 (HMGB1) and receptor for advanced glycation end products (RAGE) are involved in multidrug resistance protein 1 (MDR1) regulation and GEM resistance. Thus, this study aimed to explore the function of lucidone in tumor cytotoxicity and chemosensitivity through the suppression of RAGE-initiated signaling in PDAC cells. The data showed that lucidone significantly promoted apoptotic cell death and inhibited the expression of autophagic proteins (Atg5, Beclin-1, LC3-II, and Vps34) and MDR1 by inhibiting the HMGB1/RAGE/PI3K/Akt axis in both MIA Paca-2 cells and MIA Paca-2GEMR cells (GEM-resistant cells). Notably, convincing data were also obtained in experiments involving RAGE-specific siRNA transfection. In addition, remarkable cell proliferation was observed after treatment with lucidone combined with GEM, particularly in MIA Paca-2GEMR cells, indicating that lucidone treatment enhanced chemosensitivity. Collectively, this study provided the underlying mechanism by which lucidone treatment inhibited HMGB1/RAGE-initiated PI3K/Akt/MDR1 signaling and consequently enhanced chemosensitivity in PDAC.

Curcumin treatment attenuates cisplatin-induced gastric mucosal inflammation and apoptosis through the NF- κ B and MAPKs signaling pathway

To investigate the protective effects of curcumin (Cur) on gastric mucosal injury induced by cisplatin (DDP), and explore possible molecular mechanisms. A mouse of gastric mucosal injury was established by intraperitoneal injection of DDP (27 mg/kg). Thirty mice were randomly divided into control group, DDP group and DDP + Cur group. Serum and gastric mucosal samples were collected on the 7th day after Cur treatment. The index of gastric mucosa injury was calculated, and the expression levels of inflammation, apoptosis and signaling pathway proteins were evaluated using hematoxylin and eosin staining, ELISA and western blotting analysis. These data showed that Cur treatment significantly attenuated DDP-induced decrease in body weight, food intake, fat and muscle ratios, and improved the gross gastric injury, scores of ulcer index, and histopathology changes triggered by DDP ( p < .05). Meanwhile, Cur significantly decreased serum IL-23 and IL-17 proteins, reduced the expression levels of gastric mucosal IL-1β, TNF- α and MPO, and restored the level of IL-10 protein ( p < .05). Moreover, Cur treatment significantly inhibited the expression levels of Caspase-3, PARP and Bax, and increased the expression of Bcl-2 protein. Furthermore, Cur treatment significantly decreased the expression levels of IL-1R, MyD88 and TAK1, and also repressed the activation of NF-κB and nuclear translocation of NF-κB p65. And more importantly, Cur treatment significantly inhibited DDP-induced gastric mucosal JNK1/2, ASK1, P38 and JUN phosphorylation, and promoted the phosphorylation of ERK1/2 and C-Myc proteins. Our data suggest that Cur treatment alleviates DDP-induced gastric mucosal inflammation and apoptosis, which may be mediated through the NF- κ B and MAPKs signaling pathway.

Diallyl disulfide and diallyl trisulfide in garlic as novel therapeutic agents to overcome drug resistance in breast cancer

Breast cancer is one of the leading causes of cancer-related deaths in women worldwide. It is a cancer that originates from the mammary ducts and involves mutations in multiple genes. Recently, the treatment of breast cancer has become increasingly challenging owing to the increase in tumor heterogeneity and aggressiveness, which gives rise to therapeutic resistance. Epidemiological, population-based, and hospital-based case-control studies have demonstrated an association between high intake of certain Allium vegetables and a reduced risk in the development of breast cancer. Diallyl disulfide (DADS) and diallyl trisulfide (DATS) are the main allyl sulfur compounds present in garlic, and are known to exhibit anticancer activity as they interfere with breast cancer cell proliferation, tumor metastasis, and angiogenesis. The present review highlights multidrug resistance mechanisms and their signaling pathways in breast cancer. This review discusses the potential anticancer activities of DADS and DATS, with emphasis on drug resistance in triple-negative breast cancer (TNBC). Understanding the anticancer activities of DADS and DATS provides insights into their potential in targeting drug resistance mechanisms of TNBC, especially in clinical studies.

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The review describes the causes of drug resistance in TNBC.

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The effects of DADS and DATS on drug resistance mechanisms in TNBC are presented.

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The impacts of DADS and DATS on metastasis of TNBC are discussed.

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Antitumor immune activities of DADS and DATS against TNBC are illustrated.

Nanoscale Formulations: Incorporating Curcumin into Combination Strategies for the Treatment of Lung Cancer

Lung cancer remains the most common cancer worldwide. Although significant advances in screening have been made and early diagnosis strategies and therapeutic regimens have been developed, the overall survival rate remains bleak. Curcumin is extracted from the rhizomes of turmeric and exhibits a wide range of biological activities. In lung cancer, evidence has shown that curcumin can markedly inhibit tumor growth, invasion and metastasis, overcome resistance to therapy, and even eliminate cancer stem cells (CSCs). Herein, the underlying molecular mechanisms of curcumin were summarized by distinct biological processes. To solve the limiting factors that curtail the clinical applications of curcumin, nanoformulations encapsulating curcumin were surveyed in detail. Nanoparticles, including liposomes, micelles, carbon nanotubes (CNTs), solid lipid nanoparticles (SLNs), nanosuspensions, and nanoemulsions, were explored as proper carriers of curcumin. Moreover, it was firmly verified that curcumin has the ability to sensitize lung cancer cells to chemotherapeutic drugs, such as cisplatin and docetaxel, and to various targeted therapies. Regarding the advantages and drawbacks of curcumin, we concluded that combination therapy based on nanoparticles would be the optimal approach to broaden the application of curcumin in the clinic in the near future.

Five metastasis-related mRNAs signature predicting the survival of patients with liver hepatocellular carcinoma

Backgrounds

Liver hepatocellular carcinoma (HCC) is one of the most malignant tumors, of which prognosis is unsatisfactory in most cases and metastatic of HCC often results in poor prognosis. In this study, we aimed to construct a metastasis- related mRNAs prognostic model to increase the accuracy of prediction of HCC prognosis.

Methods

Three hundred seventy-four HCC samples and 50 normal samples were downloaded from The Cancer Genome Atlas (TCGA) database, involving transcriptomic and clinical data. Metastatic-related genes were acquired from HCMBD website at the same time. Two hundred thirty-three samples were randomly divided into train dataset and test dataset with a proportion of 1:1 by using caret package in R. Kaplan-Meier method and univariate Cox regression analysis and lasso regression analysis were performed to obtain metastasis-related mRNAs which played significant roles in prognosis. Then, using multivariate Cox regression analysis, a prognostic prediction model was established. Transcriptome and clinical data were combined to construct a prognostic model and a nomogram for OS evaluation. Functional enrichment in high- and low-risk groups were also analyzed by GSEA. An entire set based on The International Cancer Genome Consortium(ICGC) database was also applied to verify the model. The expression levels of SLC2A1, CDCA8, ATG10 and HOXD9 are higher in tumor samples and lower in normal tissue samples. The expression of TPM1 in clinical sample tissues is just the opposite.

Results

One thousand eight hundred ninety-five metastasis-related mRNAs were screened and 6 mRNAs were associated with prognosis. The overall survival (OS)-related prognostic model based on 5 MRGs (TPM1,SLC2A1, CDCA8, ATG10 and HOXD9) was significantly stratified HCC patients into high- and low-risk groups. The AUC values of the 5-gene prognostic signature at 1 year, 2 years, and 3 years were 0.786,0.786 and 0.777. A risk score based on the signature was a significantly independent prognostic factor (HR = 1.434; 95%CI = 1.275–1.612; P < 0.001) for HCC patients. A nomogram which incorporated the 5-gene signature and clinical features was also built for prognostic prediction. GSEA results that low- and high-risk group had an obviously difference in part of pathways. The value of this model was validated in test dataset and ICGC database.

Conclusion

Metastasis-related mRNAs prognostic model was verified that it had a predictable value on the prognosis of HCC, which could be helpful for gene targeted therapy.

Role of Glycated High Mobility Group Box-1 in Gastric Cancer

Advanced glycation end products (AGEs) are produced in response to a high-glucose environment and oxidative stress and exacerbate various diseases. Nε-(Carboxymethyl)lysine (CML) is an AGE that is produced by the glycation of lysine residues of proteins. There are a few reports on alterations in protein function due to CML modification; however, its association with cancer is not clear. We investigated the significance of CML modification in high mobility group box protein-1 (HMGB1), a cytokine that is significantly associated with cancer progression. Treatment of the gastric cancer cell lines TMK1 and MKN74 with glyoxal or glucose resulted in increased CML modification compared to untreated cells. CML-HMGB1 was modified via oxidation and more pronouncedly activated the receptor for AGE and downstream AKT and NF-κB compared to naïve HMGB1 and oxidized HMGB1. CML-HMGB1 bound with reduced affinity to DNA and histone H3, resulting in enhanced extranuclear translocation and extracellular secretion. Treatment of gastric cancer cells with CML-HMGB1 enhanced cell proliferation and invasion, sphere formation, and protection from thapsigargin-induced apoptosis, and decreased 5-FU sensitivity in comparison to HMGB1. Further, CML-HMGB1 was detected at various levels in all the 10 gastric cancer tumor specimens. HMGB1 levels correlated with primary tumor progression and distant metastasis, whereas CML-HMGB1 levels were associated with primary tumor progression, lymph node metastasis, distant metastasis, and stage. In addition, CML-HMGB1 levels correlated with oxidative stress in cancer tissues and resistance to neoadjuvant therapy. Therefore, CML modification of HMGB1 enhanced the cancer-promoting effect of HMGB1. In this study, CML-HMGB1 has been highlighted as a new therapeutic target, and analysis of the molecular structure of CML-HMGB1 is desired in the future.

Circ_0000260 Regulates the Development and Deterioration of Gastric Adenocarcinoma with Cisplatin Resistance by Upregulating MMP11 via Targeting MiR-129-5p

Background

Cisplatin (CDDP) plays a vital role in the treatment of advanced gastric adenocarcinoma (GAC); however, the development of chemoresistance depletes the overall benefit of CDDP. This study harbored the aim to investigate the role of a novel circular RNA (circRNA), circ_0000260, in DDP-resistant GAC and provide a potential mechanism to explain its function.

Methods

The morphology of tumor tissues and normal tissues was observed by hematoxylin-eosin (HE) staining. The isolated exosomes were observed and examined using transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA). The expression of circ_0000260, miR-129-5p and matrix metalloproteinase 11 (MMP11) mRNA was measured by quantitative real-time polymerase chain reaction (qRT-PCR). The protein levels of CD63, CD81, fibronectin, vitronectin and MMP11 were detected by Western blot. Cell viability, colony formation, cell apoptosis, migration, invasion and cell adhesion were monitored by cell counting kit-8 (CCK-8) assay, colony formation assay, flow cytometry assay, scratch assay, transwell assay and cell adhesion assay, respectively. The interaction between miR-129-5p and circ_0000260 or MMP11 predicted by bioinformatics analysis was verified by dual-luciferase reporter assay. Animal experiments were performed in nude mice to explore the role of circ_0000260 in vivo.

Results

The expression of circ_0000260 was promoted in tumor tissues and serum-derived exosomes of GAC patients, and circ_0000260 expression in CDDP-resistant tumor tissues was higher than that in CDDP-sensitive tumor tissues. Circ_0000260 knockdown lessened CDDP chemoresistance, suppressed cell proliferation, migration, invasion and adhesion, and induced apoptosis. In mechanism, circ_0000260 regulated the expression of MMP11 by targeting miR-129-5p. MiR-129-5p inhibition could reverse the functions of circ_0000260 knockdown, and MMP11 knockdown could also reverse the effects of miR-129-5p inhibition. Besides, circ_0000260 knockdown attenuated CDDP resistance during tumor growth in vivo by regulating the expression of miR-129-5p and MMP11.

Conclusion

Circ_0000260 regulated CDDP chemoresistance of GAC by promoting MMP11 expression via targeting miR-129-5p.

Establishment of Acquired Cisplatin Resistance in Ovarian Cancer Cell Lines Characterized by Enriched Metastatic Properties with Increased Twist Expression

Ovarian cancer (OC) is the most lethal of the gynecologic cancers, and platinum-based treatment is a part of the standard first-line chemotherapy regimen. However, rapid development of acquired cisplatin resistance remains the main cause of treatment failure, and the underlying mechanism of resistance in OC treatment remains poorly understood. Faced with this problem, our aim in this study was to generate cisplatin-resistant (CisR) OC cell models in vitro and investigate the role of epithelial–mesenchymal transition (EMT) transcription factor Twist on acquired cisplatin resistance in OC cell models. To achieve this aim, OC cell lines OV-90 and SKOV-3 were exposed to cisplatin using pulse dosing and stepwise dose escalation methods for a duration of eight months, and a total of four CisR sublines were generated, two for each cell line. The acquired cisplatin resistance was confirmed by determination of 50% inhibitory concentration (IC₅₀) and clonogenic survival assay. Furthermore, the CisR cells were studied to assess their respective characteristics of metastasis, EMT phenotype, DNA repair and endoplasmic reticulum stress-mediated cell death. We found the IC₅₀ of CisR cells to cisplatin was 3–5 times higher than parental cells. The expression of Twist and metastatic ability of CisR cells were significantly greater than those of sensitive cells. The CisR cells displayed an EMT phenotype with decreased epithelial cell marker E-cadherin and increased mesenchymal proteins N-cadherin and vimentin. We observed that CisR cells showed significantly higher expression of DNA repair proteins, X-ray repair cross-complementing protein 1 (XRCC1) and poly (ADP-ribose) polymerases 1 (PARP1), with significantly reduced endoplasmic reticulum (ER) stress-mediated cell death. Moreover, Twist knockdown reduced metastatic ability of CisR cells by suppressing EMT, DNA repair and inducing ER stress-induced cell death. In conclusion, we highlighted the utilization of an acquired cisplatin resistance model to identify the potential role of Twist as a therapeutic target to reverse acquired cisplatin resistance in OC.