ATP6V1B1 regulates ovarian cancer progression and cisplatin sensitivity through the mTOR/autophagy pathway

Early detection and effective chemotherapy for ovarian cancer, a serious gynecological malignancy, require further progress. This study aimed to investigate the molecular mechanism of ATPase H+-Transporting V1 Subunit B1 (ATP6V1B1) in ovarian cancer development and chemoresistance. Our data show that ATP6V1B1 is upregulated in ovarian cancer and correlated with decreased progression-free survival. Gain- and loss-of-function experiments demonstrated that ATP6V1B1 promotes the proliferation, migration, and invasion of ovarian cancer cells in vitro, while ATP6V1B1 knockout inhibits tumor growth in vivo. In addition, knocking down ATP6V1B1 increases the sensitivity of ovarian cancer cells to cisplatin. Mechanistic studies showed that ATP6V1B1 regulates the activation of the mTOR/autophagy pathway. Overall, our study confirmed the oncogenic role of ATP6V1B1 in ovarian cancer and revealed that ATP6V1B1 promotes ovarian cancer progression via the mTOR/autophagy axis.

USP43 impairs cisplatin sensitivity in epithelial ovarian cancer through HDAC2-dependent regulation of Wnt/β-catenin signaling pathway

Epithelial ovarian cancer (EOC) is the leading cause of cancer death all over the world. USP43 functions as a tumor promoter in various malignant cancers. Nevertheless, the biological roles and mechanisms of USP43 in EOC remain unknown. In this study, USP43 was highly expressed in EOC tissues and cells, and high expression of USP43 were associated with a poor prognosis of EOC. USP43 overexpression promoted EOC cell proliferation, enhanced the ability of migration and invasion, decreased cisplatin sensitivity and inhibited apoptosis. Knockdown of USP43 in vitro effectively retarded above malignant progression of EOC. In vivo xenograft tumors, silencing USP43 slowed tumor growth and enhanced cisplatin sensitivity. Mechanistically, USP43 inhibited HDAC2 degradation and enhanced HDAC2 protein stability through its deubiquitylation function. USP43 diminished the sensitivity of EOC cells to cisplatin through activation of the Wnt/β-catenin signaling pathway mediated by HDAC2. Taken together, the data in this study revealed the functions of USP43 in proliferation, migration, invasion, chemoresistance of EOC cells, and the mechanism of HDAC2-mediated Wnt/β-catenin signaling pathway. Thus, USP43 might serve as a potential target for the control of ovarian cancer progression.

ANKRD2 expression combined with TNFRSF19 expression for evaluating the prognosis of oral squamous cell carcinoma patients

Objective

As an important chemotherapy drug, cisplatin has been widely used in the treatment of many cancers. However, many patients, including oral squamous cell carcinoma (OSCC) patients, experience unacceptable outcomes from cisplatin treatment. Thus, we devised a risk model for predicting the sensitivity of OSCC patients to cisplatin treatment, to provide a reference for clinical practice.

Methods

CAL-27 and SCC-9 cell lines treated or not with cisplatin and data from The Cancer Genome Atlas (TCGA) were screened for simultaneously and significantly differentially expressed genes. Next, we built a risk model for predicting cisplatin sensitivity in OSCC patients. Reverse transcription-polymerase chain reaction (RT-PCR), pathological samples and clinical data were used to examine the reliability of the model.

Results

ANKRD2 and TNFRSF19 were differentially expressed between the OSCC metastasis cell line HSC-3 treated and not treated with cisplatin, as well as between the OSCC cell line SCC-25 and the cell line SCC25-DDP, which has cisplatin chemoresistance. We found that the expression of ANKRD2 and TNFRSF19 had a significant influence on the prognosis of OSCC patients. The risk model that combined ANKRD2 and TNFRSF19 to predict sensitivity to cisplatin in OSCC patients was confirmed by analysing the pathological samples and follow-up information of clinical patients.

Conclusions

The expression of ANKRD2 and TNFRSF19 is associated with cisplatin sensitivity and prognosis in patients with OSCC. The survival outcome of patients with oral squamous cell carcinoma (OSCC) was found to be significantly worse in those with high expression of ANKRD2 combined with low expression of TNFRSF19. ANKRD2 and TNFRSF19 may be targets for cisplatin sensitivity prediction in OSCC patients. These findings may provide novel strategies for overcoming cisplatin resistance.

LASS2 enhances chemosensitivity to cisplatin by inhibiting PP2A-mediated β-catenin dephosphorylation in a subset of stem-like bladder cancer cells

BACKGROUND

The benefits of first-line, cisplatin-based chemotherapy for muscle-invasive bladder cancer are limited due to intrinsic or acquired resistance to cisplatin. Increasing evidence has revealed the implication of cancer stem cells in the development of chemoresistance. However, the underlying molecular mechanisms remain to be elucidated. This study investigates the role of LASS2, a ceramide synthase, in regulating Wnt/β-catenin signaling in a subset of stem-like bladder cancer cells and explores strategies to sensitize bladder cancer to cisplatin treatment.

METHODS

Data from cohorts of our center and published datasets were used to evaluate the clinical characteristics of LASS2. Flow cytometry was used to sort and analyze bladder cancer stem cells (BCSCs). Tumor sphere formation, soft agar colony formation assay, EdU assay, apoptosis analysis, cell viability, and cisplatin sensitivity assay were used to investigate the functional roles of LASS2. Immunofluorescence, immunoblotting, coimmunoprecipitation, LC-MS, PCR array, luciferase reporter assays, pathway reporter array, chromatin immunoprecipitation, gain-of-function, and loss-of-function approaches were used to investigate the underlying mechanisms. Cell- and patient-derived xenograft models were used to investigate the effect of LASS2 overexpression and a combination of XAV939 on cisplatin sensitization and tumor growth.

RESULTS

Patients with low expression of LASS2 have a poorer response to cisplatin-based chemotherapy. Loss of LASS2 confers a stem-like phenotype and contributes to cisplatin resistance. Overexpression of LASS2 results in inhibition of self-renewal ability of BCSCs and increased their sensitivity to cisplatin. Mechanistically, LASS2 inhibits PP2A activity and dissociates PP2A from β-catenin, preventing the dephosphorylation of β-catenin and leading to the accumulation of cytosolic phospho-β-catenin, which decreases the transcription of the downstream genes ABCC2 and CD44 in BCSCs. Overexpression of LASS2 combined with a tankyrase inhibitor (XAV939) synergistically inhibits tumor growth and restores cisplatin sensitivity.

CONCLUSIONS

Targeting the LASS2 and β-catenin pathways may be an effective strategy to overcome cisplatin resistance and inhibit tumor growth in bladder cancer patients.

Downregulation of BUBR1 regulates the proliferation and cell cycle of breast cancer cells and increases the sensitivity of cells to cisplatin

Breast cancer (BC) is a significant tissue for women's health worldwide. The spindle assembly checkpoint protein family includes BUBR1 (Bub1-related kinase or MAD3/Bub1b). High expression of BUBR1 promotes cell cycle disorders, leading to cell carcinogenesis and cancer progression. However, the underlying molecular mechanism and the role of BUBR1 in BC progression are unclear. The published dataset was analyzed to evaluate the clinical relevance of BUBR1. BUBR1 was knocked down in BC cells using shRNA. The CCK-8 assay was used to measure the cell viability, and mRNA and protein expression levels were detected by RT-qPCR and Western blot (WB). Cell apoptosis and cell cycle were detected by flow cytometry. Subcutaneous xenograft model was used to assess in vivo tumor growth. BUBR1 was found to be highly expressed in BC. The high expression of BUBR1 was associated with poor prognosis of BC patients. Upon BUBR1 knockdown using shRNA, the proliferation and metastatic ability of cells were decreased. Moreover, the cells with BUBR1 knockdown underwent cell cycle arrest. And the results showed that BUBR1 loss inhibited the phosphorylation of TAK1/JNK. In vitro and in vivo studies indicated the knockdown of BUBR1 rendered the BC cells more sensitive to cisplatin. In summary, BUBR1 may be a potential therapeutic target for BC and targeting BUBR1 may help overcome cisplatin resistance in BC patients.

MicroRNA-367-3p directly targets RAB23 and inhibits proliferation, migration and invasion of bladder cancer cells and increases cisplatin sensitivity

OBJECTIVES

This study investigated the biological role of miR-367-3p upregulation in bladder cancer and verified the mutual relation between miR-367-3p and RAB23.

MATERIALS AND METHODS

Expression levels of miR-367-3p were determined by RT-qPCR in bladder cancer cell lines and human bladder cancer tissues. The effects of miR-367-3p on proliferation, migration and invasion were evaluated by cell colony formation assays, wound healing assays and trans-well assays, respectively. The effects of miR-367-3p and RAB23 on cisplatin sensitivity of bladder cancer cells were assessed by CCK-8 assay. The expression of its target-RAB23 was determined by western blotting in T24, 5637. Plasmids used in dual-luciferase assays were constructed to confirm the action of miR-367-3p on downstream target-RAB23 in T24 cells. And also, the role of miR-367-3p in tumorigenesis was also confirmed in nude mouse models.

RESULTS

The downregulation of miR-367-3p was observed in human bladder cancer tissues. MiR-367-3p downregulation positively correlated with tumor stage and tumor grade. MiR-367-3p overexpression in T24, 5637 cells suppressed the proliferation, migration, and invasion of bladder cancer cells in vitro while decreasing IC50 values under T24 and 5637 cisplatin treatment conditions. RAB23 was shown to be upregulated in bladder cancer tissues and cell lines. MiR-367-3p directly bound to the 3' UTR of RAB23 in T24 cells. RAB23 was potentially accounted for the aforementioned functions of miR-367-3p. Tumor formation experiments in nude mouse models confirmed that overexpression of miR-367-3p could inhibit tumor growth and invasion in vivo.

CONCLUSIONS

miR-367-3p acts as a tumor suppressor in bladder cancer by downregulating RAB23 signaling. We conjecture that miR-367-3p-mediated downregulation of RAB23 expression may be a new therapeutic strategy for bladder cancer treatment.

SETD8, a frequently mutated gene in cervical cancer, enhances cisplatin sensitivity by impairing DNA repair

BACKGROUND

Cisplatin is commonly used to treat cervical cancer while drug resistance limits its effectiveness. There is an urgent need to identify strategies that increase cisplatin sensitivity and improve the outcomes of chemotherapy.

RESULTS

We performed whole exome sequencing (WES) of 156 cervical cancer tissues to assess genomic features related to platinum-based chemoresistance. By using WES, we identified a frequently mutated locus SETD8 (7%), which was associated with drug sensitivity. Cell functional assays, in vivo xenografts tumor growth experiments, and survival analysis were used to investigate the functional significance and mechanism of chemosensitization after SETD8 downregulation. Knockdown of SETD8 increased the responsiveness of cervical cancer cells to cisplatin treatment. The mechanism is exerted by reduced binding of 53BP1 to DNA breaks and inhibition of the non-homologous end joining (NHEJ) repair pathway. In addition, SETD8 expression was positively correlated with resistance to cisplatin and negatively associated with the prognosis of cervical cancer patients. Further, UNC0379 as a small molecule inhibitor of SETD8 was found to enhance cisplatin sensitivity both in vitro and in vivo.

CONCLUSIONS

SETD8 was a promising therapeutic target to ameliorate cisplatin resistance and improve the efficacy of chemotherapy.

Long non-coding RNA DSCAS regulates cisplatin sensitivity in lung squamous cell carcinoma by competitively binding to miR-646-3p

Background

Platinum-based chemotherapy is the main treatment for advanced lung squamous cell carcinoma (LUSC). Eventually, patients with LUSC develop resistance to cisplatin, which affects the prognosis. Hence, the researchers sought to find a lncRNA in LUSC that affects resistance to cisplatin.

Methods

The lncRNA microarray assay was used to screen the differential expression of lncRNA. qPCR was used to detect lncRNA DSCAS (DSCAS) expression in tissues and cell lines. Lentiviral transfection was used to regulate the expression of DSCAS. CCK-8, colony formation, wound healing, transwell, and flow cytometry assays were used to assess the biological behaviors and sensitivity to cisplatin of LUSC cell. RNA-RNA interaction was tested using the dual luciferase reporting assay, RNA-IP, and RNA-RNA pull-down assay. The downstream pathway of DSCAS was verified by qPCR and Western blotting assays.

Results

DSCAS was highly expressed in LUSC tissues and cells, and its expression levels were higher in cisplatin-insensitive tissues than in cisplatin-sensitive tissues. Elevation of DSCAS promoted cell proliferation, migration and invasion as well as increased cisplatin resistance of lung cancer cells, while demotion of DSCAS inhibited cell proliferation, migration and invasion as well as decreased the cisplatin resistance of lung cancer cells. DSCAS bound to miR-646-3p to regulate the expression of Bcl-2 and Survivin, which affected the cell apoptosis and sensitivity to cisplatin in LUSC cells.

Conclusions

DSCAS regulates biological behavior and cisplatin sensitivity in LUSC cells by competitively binding to miR-646-3p to mediate the expression of Survivin and Bcl-2, known as apoptosis-related proteins.

CARD9 contributes to ovarian cancer cell proliferation, cycle arrest, and cisplatin sensitivity

BACKGROUND

Ovarian cancer recurrence and chemotherapy resistance are still urgent issues, and exploring the mechanisms of metastasis and chemotherapy resistance is beneficial to the development of therapeutic methods. Caspase recruitment domain family member 9 (CARD9) and homeobox B5 (HOXB5) are related and both are upregulated in ovarian cancer. This study aimed to define their functions in ovarian cancer cell proliferation, migration, and cisplatin sensitivity.

RESULTS

The levels of CARD9 were detected in acquired ovarian cancer tissues and cell lines. CARD9 was indeed abnormally upregulated in them. CARD9 knockdown significantly suppressed cell proliferation, colony formation, migration, cycle arrest, and cisplatin sensitivity. HOXB5 bound to the CARD9 promoter, and HOXB5 overexpression reversed the regulation by CARD9 knockdown in cells, as well as the activation of NF-κB signaling. This indicated that CARD9 was positively regulated by HOXB5 in ovarian cancer cells.

CONCLUSION

Together, CARD9 is involved in ovarian cancer cell proliferation, migration, and cisplatin sensitivity via NF-κB signaling after transcriptional activation by HOXB5.

Down-regulation of USP22 reduces cell stemness and enhances the sensitivity of pancreatic cancer cells to cisplatin by inactivating the Wnt/β-catenin pathway

OBJECTIVE

Pancreatic cancer (PC) has the worst prognosis of all common cancers worldwide. This study was intended to investigate the role of ubiquitin specific peptidase 22 (USP22) in cisplatin sensitivity of PC cells and its regulatory mechanism.

METHODS

The expression of USP22 and the toxicity of cisplatin to PC cells were detected. The two cell lines AsPC-1 and CAPAN-1 with the most differential drug resistance were selected. By down-expressing USP22 in CAPAN-1 cells and over-expressing USP22 in AsPC-1 cells, the survival rate of PC cells treated with cisplatin was detected. The mRNA expressions of stem cell markers, cell stemness, migration ability and apoptosis of PC cells were detected. The expression of Wnt/β-catenin pathway related proteins was detected. The role of the Wnt/β-catenin pathway in PC cell stemness and cisplatin sensitivity was explored after adding the inhibitor HLY78 and activator DKK1.

RESULTS

USP22 was highly-expressed in PC cells, and the sensitivity of PC cells to cisplatin was negatively-correlated with USP22 expression. Downregulation of USP22 raised the sensitivity of PC cells to cisplatin, reduced the levels of stem cell markers, reduced the tumor sphere formation and migration, and promoted apoptosis. Silencing USP22 inhibited the Wnt/β-catenin pathway. Inhibition of USP22 reduced the cell stemness and augmented the sensitivity of PC cells to cisplatin by inhibiting the Wnt/β-catenin pathway.

CONCLUSION

Silencing USP22 can inhibit the Wnt/β-catenin pathway to reduce cell stemness and enhance the sensitivity of PC cells to cisplatin.

Cisplatin-induced pyroptosis is mediated via the CAPN1/CAPN2-BAK/BAX-caspase-9-caspase-3-GSDME axis in esophageal cancer

Esophageal cancer is the seventh most common cancer globally. Chemotherapy resistance remains a significant challenge in the treatment of esophageal cancer patients. Cisplatin can damage tumor cells by inducing pyroptosis. However, the underlying molecular mechanisms remain unclear. In this work, we aim to investigate pyroptosis-dependent molecular mechanisms underlying cisplatin sensitivity and find potential biomarkers to predict response to cisplatin-based chemotherapy for esophageal cancer patients. Pyroptosis-associated proteins were screened via proteomics for esophageal cancer (n = 124) and bioinformatics analysis. We observed that high calpain-1 (CAPN1) and calpain-2 (CAPN2) expression were associated with favorable clinical outcomes and prolonged survival in esophageal cancer patients. We employed immunohistochemistry to evaluate the expression of CAPN1 and CAPN2 in pretreatment tumor biopsies from 108 patients with esophageal cancer who received concurrent chemoradiotherapy (CCRT). These results suggested that esophageal cancer patients with high expression of both CAPN1 and CAPN2 are likely to experience a complete response to CCRT and have significantly better survival. Western blotting, LDH release, calpain activity and cell viability assays indicated that cisplatin could activate calpain activity, while calpain inhibition or knockout suppressed cisplatin-induced pyroptosis. Mechanistically, we uncovered a novel mechanism whereby cisplatin induced pyroptosis via activation of a CAPN1/CAPN2-BAK/BAX-caspase-9-caspase-3-GSDME signaling axis in esophageal cancer cells. Collectively, this study is the first to explore the effects of calpain on cisplatin-induced pyroptosis in esophageal cancer cells. Further, our findings also imply that the combination of CAPN1 and CAPN2 could be considered as a promising biomarker of cisplatin sensitivity and prognosis in patients with esophageal cancer, providing a possibility to guide individualized treatment.

HNRNPUL1 inhibits cisplatin sensitivity of esophageal squamous cell carcinoma through regulating the formation of circMAN1A2

Cisplatin (CDDP) is widely used for chemotherapy of esophageal squamous cell carcinoma (ESCC) but the drug resistance limits its therapeutic benefit. Heterogeneous nuclear ribonucleoprotein U-like 1 (HNRNPUL1) belongs to the family of RNA-binding proteins (RBPs) and is involved in DNA damage repair. To investigate whether and how HNRNPUL1 affects CDDP resistance of ESCC, we evaluated the expression of HNRNPUL1 and found that it was associated with recurrence in ESCC patients receiving postoperative platinum-based chemotherapy and was an independent prognostic factor for disease-free survival (DFS). Besides, we showed that the reduced expression of HNRNPUL1 enhanced the CDDP sensitivity of ESCC cells. Furthermore, RNA immunoprecipitation coupled with high-throughput sequencing (RIP-seq) were performed and a range of HNRNPUL1-binding RNAs influenced by CDDP treatment were identified followed by bioinformatics analysis. In terms of mechanism, we found that HNRNPUL1 inhibited CDDP sensitivity of ESCC cells by regulating the CDDP sensitivity-inhibited circular RNA (circRNA) MAN1A2 formation. Taken together, our results first demonstrated the role of HNRNPUL1 in CDDP resistance of ESCC and suggested that HNRNPUL1 may be a potential target of ESCC chemotherapy.

Hypoxia-induced ROS promotes mitochondrial fission and cisplatin chemosensitivity via HIF-1α/Mff regulation in head and neck squamous cell carcinoma

PURPOSE

Chemotherapy based on cisplatin (CDDP) has been established as the treatment of choice for head and neck squamous cell carcinoma (HNSCC). Malignant tumors respond to microenvironmental alterations through a dynamic balance between mitochondrial fission and fusion. HNSCCs are known to exhibit hypoxic conditions, yet the respective effects and underlying mechanisms of hypoxia on chemosensitivity and mitochondrial dynamics remain to be resolved.

METHODS

The effect of hypoxia on the chemosensitivity of HNCC cells was determined by flow cytometry. Mitochondrial fission factor (Mff) expression was assessed by RT-PCR and Western blotting in hypoxic HNSCC cells, and further verified in primary CDDP-sensitive and CDDP-resistant HSNCC samples. The biological function of Mff was evaluated by loss of function and gain of function analyses, both in vitro and in vivo.

RESULTS

We found that hypoxia promoted mitochondrial fission and CDDP sensitivity in HNSCC cells. Importantly, Mff was found to be correlated with chemosensitivity in primary clinical samples under hypoxic conditions. Hypoxia-inducible factor 1α (HIF-1α) was found to markedly increase Mff transcription and to directly bind to Mff. Hypoxia enhanced the release of reactive oxygen species (ROS) and upregulated the expression of Mff via HIF-1α in HNSCC cells. ROS depletion in HNSCC cells attenuated HIF-1α expression, Mff expression and mitochondrial fission. Moreover, Mff knockdown led to suppression of hypoxia-induced mitochondrial fission and to decreased CDDP chemosensitivity in vivo and in vitro.

CONCLUSIONS

Our findings indicate that hypoxia-induced release of ROS can promote mitochondrial fission and CDDP chemosensitivity via HIF1α/Mff regulation in HNSCC cells, indicating that Mff may serve as a biomarker to predict neoadjuvant chemosensitivity in HNSCC patients and as a target for overcoming chemoresistance.

Magnoflorine inhibits the malignant phenotypes and increases cisplatin sensitivity of osteosarcoma cells via regulating miR-410-3p/HMGB1/NF-κB pathway

AIMS

Magnoflorine is an essential type of alkaloid and possesses anti-tumor activity in multiple cancers. Recent studies have demonstrated that magnoflorine plays tumor-suppressive roles in gastric and breast cancers. However, its role in osteosarcoma (OS) tumorigenesis is enigmatic. This study aimed to investigate the role and mechanism of magnoflorine in OS.

MATERIALS AND METHODS

Two human OS cells (MG-63 and U-2 OS) were treated with different concentrations of magnoflorine. Cell viability and invasion were then detected by Cell Counting Kit-8 and Transwell assay, respectively. And the effects of magnoflorine on the epithelial-mesenchymal transition (EMT) and cisplatin sensitivity were also measured. To explore the potential mechanism, we assayed the influence of magnoflorine on the miR-410-3p/HMGB1/NF-κB signaling pathway. Additionally, rescue experiments were performed to further confirm the regulation mechanism of magnoflorine.

KEY FINDINGS

Magnoflorine inhibited the viability, invasion, and EMT of OS cells in a dose-dependent manner. And it increased the sensitivity of OS cells to cisplatin. Magnoflorine significantly suppressed HMGB1 expression and NF-κB activation, but upregulated miR-410-3p level. Overexpression of HMGB1 promoted NF-κB activation and reversed the effects of magnoflorine on the viability, invasion, EMT and cisplatin sensitivity of OS cells. miR-410-3p mimic inhibited the EMT of OS cells, which was restored by HMGB1 upregulation. And miR-410-3p inhibitor abrogated the influence of magnoflorine on HMGB1 expression in OS cells.

SIGNIFICANCE

Magnoflorine inhibited the malignant phenotypes and increased cisplatin sensitivity of OS cells via modulating miR-410-3p/HMGB1/NF-κB pathway. These results indicated that magnoflorine might be a novel drug for the treatment of OS.

MiR-486-5p enhances cisplatin sensitivity of human muscle-invasive bladder cancer cells by induction of apoptosis and down-regulation of metastatic genes

OBJECTIVES

Cisplatin is one of the common chemotherapy drugs for bladder cancer, and resistance to this drug is one of the major obstacles to effective chemotherapy. MicroRNAs (miRNAs) are a category of small noncoding RNAs that can regulate the expression of numerous genes. Recent studies showed that miRNAs can act as a powerful regulator of chemo-sensitivity in cancer cells. Hence, this study aimed to investigate the effects of miRNA-486-5p on cisplatin-sensitivity of different bladder cancer cells.

MATERIAL AND METHODS

The 5637 and EJ138 cancer cells were treated with miRNA-486-5p and cisplatin, individually or in combination.

RESULTS

Afterward, the cytotoxicity effects of these treatments were determined by MTT assay and the increased cisplatin-sensitivity observed in both cell lines, especially, 5637 cells. Moreover, subG1 phase cell cycle arrest, changes in the expression of caspase-9, caspase-3, P53, SIRT1, OLFM4, SMAD2, and Bcl-2 genes and nuclear fragmentation also revealed the induction of apoptosis in all treatments, which increased in combination groups. Also, the combination of miRNA-486-5p with cisplatin significantly down-regulated the expression of migration associated genes including ROCK, CD44, and MMP-9 as compared with cisplatin alone.

CONCLUSION

Altogether, these results indicated that the miRNA-486-5p could induce apoptosis and inhibit cell migration ability of the cells. It seems that pre-electroporation of cells with miRNA-486-5p has useful results in the enhancement of cisplatin sensitivity of 5637 and EJ138 cancer cells and this combination may be a promising treatment strategy for bladder cancer therapy.

Apatinib suppresses tumor progression and enhances cisplatin sensitivity in esophageal cancer via the Akt/β-catenin pathway

Background

Esophageal cancer is the sixth leading cause of cancer-related mortality worldwide, which is partially due to limited progress of therapy. Apatinib, an inhibitor of VEGFR2, has a promising antitumor effect on malignancies. However, the underlying mechanism of its antitumor effect on esophageal cancer remains poorly understood.

Materials and methods

Eighteen pairs of frozen esophageal cancer and their para-cancer samples and 25 paraffin specimens from advanced esophageal cancer patients treated with cisplatin-based regimen were collected. The effects of apatinib on cell growth, cell apoptosis, cell cycle and invasion/migration of esophageal cancer cells were assessed. Bioinformatics, luciferase reporter, immunoprecipitation and immunofluorescence assays were conducted for mechanic investigation. Quantitative RT-PCR, western blotting and immunohistochemistry were used to measure the expression of functional genes. Xenograft tumor growth of mice was performed.

Results

We found that VEGFR2 was highly expressed in esophageal cancer and associated with poor efficacy of cisplatin-based treatment. Apatinib displayed profound actions against tumor cell growth of human esophageal cancer via promoting cell apoptosis and cell cycle arrest. Also, apatinib displayed the inhibitory effects on cell migration and invasion. Moreover, apatinib strongly suppressed the growth of esophageal cancer xenografts in mice. The effects of apatinib on esophageal cancer were partially dependent on its block of the VEGFR2/Akt/β-catenin pathway. Specifically, apatinib induced the degradation of β-catenin and decreased its transcriptional activity through Akt/GSK-3β repression. Further in vitro and in vivo studies revealed that low dose apatinib had a synergistic antitumor effect with cisplatin on esophageal cancer.

Conclusion

Our study indicates that apatinib suppresses tumor progression and enhances cisplatin sensitivity in esophageal cancer by deactivating the Akt/β-catenin pathway. These findings provide a theoretical foundation for using apatinib as an effective therapeutic drug for esophageal cancer.

Sophoridine inhibits lung cancer cell growth and enhances cisplatin sensitivity through activation of the p53 and Hippo signaling pathways

BACKGROUND

Sophoridine, a quinolizidine alkaloid extracted from the Chinese herb Sophora alopecuroides L., has been reported to exert antitumor effects against multiple human cancers. However, few studies have evaluated its tumor-suppressing effects and associated mechanism with respect to lung cancer, in addition to its potential to be used for clinical lung cancer treatment.

METHODS

Different types of lung cancer cells were used to investigate the antitumor effects of sophoridine using cell viability, colony formation, and cell invasion, and migration assays. To determine the signaling pathways involved, western blot analysis, quantitative real-time polymerase chain reaction, an in vivo ubiquitination assay, and immunohistochemistry were used in cellular assays and with a subcutaneous xenograft model in BALB/c mice.

RESULTS

Sophoridine significantly suppressed the proliferation of and colony formation by lung cancer cells in vitro. Transwell assays demonstrated that sophoridine also inhibited invasion and migration in lung cancer cells. In addition, sophoridine enhanced the effects of cisplatin on lung cancer cells. A mechanistic study revealed that sophoridine significantly activated the Hippo and p53 signaling pathways, and mouse xenograft experiments further confirmed in vitro findings in lung cancer cells.

CONCLUSIONS

Taken together, these results suggest that sophoridine can inhibit lung cancer progression and enhance the effects of the anticancer drug cisplatin against lung cancer cells. The mechanism of action of sophoridine might involve the Hippo and p53 signaling pathways.

Mitochondrial characteristics contribute to proliferation and migration potency of MDA-MB-231 cancer cells and their response to cisplatin treatment

AIM

Despite recent advances in therapeutic strategies, cancer is still a leading cause of mortality worldwide. Mitochondrial dysfunction is implicated in cancer initiation and metastasis, and even in chemo- and radio-resistance. However, the precise role of mitochondria in cancer is crosstalk and controversial. This study is trying to find out the effect of transferring normal mitochondria into the highly aggressive and proliferative MDA-MB-231 cancer cells, and to evaluate the effect of the transfer with/without a combination therapy with cisplatin.

MATERIALS AND METHODS

Normal mitochondria were isolated from human umbilical cord derived-mesenchymal stem cells. The mitochondria were transferred into the MDA-MB-231 cells, and also into cells with mitochondrial dysfunction induced by rhodamine red 6 (R6G). Cell proliferation and sensitivity of the cells to cisplatin were measured by cell counting after the mitochondria transfer. Also, apoptosis was evaluated by DAPI staining and in situ cell death detection (TdT-mediated dUTP nickend labeling; TUNEL) methods. Migration capability of the cells was studied by transwell assay.

KEY FINDINGS

Transfer of normal mitochondria into MDA-MB-231 cells increased cell proliferation. However, the transfer of mitochondria enhanced cisplatin-induced apoptosis in MDA-MB-231 cells in which mitochondria were already disrupted. Introduction of normal cell-derived mitochondria into the MDA-MB-231 cells increased their invasive, but decreased the migration potency of the cells in the group with mitochondrial dysfunction (MDA + RG6 + Cisplatin).

CONCLUSION

The introduction of healthy mitochondria to highly aggressive and proliferative cells would be considered as a new therapeutic modality for some types of cancer.

The oncogene Gankyrin is expressed in testicular cancer and contributes to cisplatin sensitivity in embryonal carcinoma cells

Background

Testicular germ cell cancer (TGCC) develops from pre-malignant germ neoplasia in situ (GCNIS) cells. GCNIS originates from fetal gonocytes (POU5F1⁺/MAGE-A4⁻), which fail to differentiate to pre-spermatogonia (POU5F1⁻/MAGE-A4⁺) and undergo malignant transformation. Gankyrin is an oncogene which has been shown to prevent POU5F1 degradation and specifically interact with MAGE-A4 in hepatocellular carcinoma (HCC) cells. We aimed to investigate the role of Gankyrin in progression from gonocyte to pre-invasive GCNIS and subsequent invasive TGCC.

Methods

We determined Gankyrin expression in human fetal testicular tissue (gestational weeks 9–20; n = 38), human adult testicular tissue with active spermatogenesis (n = 9), human testicular tissue with germ cell maturation delay (n = 4), testicular tissue from patients with pre-invasive GCNIS (n = 6), and invasive TGCC including seminoma (n = 6) and teratoma (n = 7). Functional analysis was performed in-vitro by siRNA knock-down of Gankyrin in the NTera2 cells (derived from embryonal carcinoma).

Results

Germ cell expression of Gankyrin was restricted to a sub-population of prespermatogonia in human fetal testes. Nuclear Gankyrin was also expressed in GCNIS cells of childhood and adult pre-invasive TGCC patients, and in GCNIS from seminoma and non-seminoma patients. Cytoplasmic expression was observed in seminoma tumour cells and NTera2 cells. Gankyrin knock-down in NTera2 cells resulted in an increase in apoptosis mediated via the TP53 pathway, whilst POU5F1 expression was unaffected. Furthermore, Gankyrin knock-down in NTera2 cells increased cisplatin sensitivity with an increase in cell death (13%, p < 0.05) following Gankyrin knock-down, when compared to cisplatin treatment alone, likely via BAX and FAS. Our results demonstrate that Gankyrin expression changes in germ cells during normal transition from gonocyte to prespermatogonia. In addition, changes in Gankyrin localisation are associated with progression of pre-invasive GCNIS to invasive TGCC. Furthermore, we found that Gankyrin is involved in the regulation of NTera2 cell survival and that a reduction in Gankyrin expression can modulate cisplatin sensitivity.

Conclusions

These results suggest that manipulation of Gankyrin expression may reduce the cisplatin dose required for the treatment of TGCC, with benefits in reducing dose-dependent side effects of chemotherapy. Further studies are required in order to assess the effects of modulating Gankyrin on GCNIS/TGCC using in vivo models.

Cisplatin-resistant triple-negative breast cancer subtypes: multiple mechanisms of resistance

BACKGROUND

Understanding mechanisms underlying specific chemotherapeutic responses in subtypes of cancer may improve identification of treatment strategies most likely to benefit particular patients. For example, triple-negative breast cancer (TNBC) patients have variable response to the chemotherapeutic agent cisplatin. Understanding the basis of treatment response in cancer subtypes will lead to more informed decisions about selection of treatment strategies.

METHODS

In this study we used an integrative functional genomics approach to investigate the molecular mechanisms underlying known cisplatin-response differences among subtypes of TNBC. To identify changes in gene expression that could explain mechanisms of resistance, we examined 102 evolutionarily conserved cisplatin-associated genes, evaluating their differential expression in the cisplatin-sensitive, basal-like 1 (BL1) and basal-like 2 (BL2) subtypes, and the two cisplatin-resistant, luminal androgen receptor (LAR) and mesenchymal (M) subtypes of TNBC.

RESULTS

We found 20 genes that were differentially expressed in at least one subtype. Fifteen of the 20 genes are associated with cell death and are distributed among all TNBC subtypes. The less cisplatin-responsive LAR and M TNBC subtypes show different regulation of 13 genes compared to the more sensitive BL1 and BL2 subtypes. These 13 genes identify a variety of cisplatin-resistance mechanisms including increased transport and detoxification of cisplatin, and mis-regulation of the epithelial to mesenchymal transition.

CONCLUSIONS

We identified gene signatures in resistant TNBC subtypes indicative of mechanisms of cisplatin. Our results indicate that response to cisplatin in TNBC has a complex foundation based on impact of treatment on distinct cellular pathways. We find that examination of expression data in the context of heterogeneous data such as drug-gene interactions leads to a better understanding of mechanisms at work in cancer therapy response.

Loss of Scribble confers cisplatin resistance during NSCLC chemotherapy via Nox2/ROS and Nrf2/PD-L1 signaling

Background

Cisplatin resistance remains a major clinical obstacle to the successful treatment of non-small cell lung cancer (NSCLC). Scribble contributes to ROS-induced inflammation and cisplatin-elevated toxic reactive oxygen species (ROS) promotes cell death. However, it is unknown whether and how Scribble is involved in the cisplatin-related cell death and the underlying mechanism of Scribble in response to chemotherapies and in the process of oxidative stress in NSCLC.

Methods

We used two independent cohorts of NSCLC samples derived from patients treated with platinum-containing chemotherapy and xenograft modeling in vivo. We analyzed the correlation between Scribble and Nox2 or Nrf2/PD-L1 both in vivo and in vitro, and explored the role of Scribble in cisplatin-induced ROS and apoptosis.

Findings

Clinical analysis revealed that Scribble expression positively correlated with clinical outcomes and chemotherapeutic sensitivity in NSCLC patients. Scribble protected Nox2 protein from proteasomal degradation. Scribble knockdown induced cisplatin resistance by blocking Nox2/ROS and apoptosis in LRR domain-dependent manner. In addition, low levels of Scribble correlated with high levels of PD-L1 via activation of Nrf2 transcription in vivo and in vitro.

Interpretations

Our study revealed that polarity protein Scribble increased cisplatin-induced ROS generation and is beneficial to chemotherapeutic outcomes in NSCLC. Although Scribble deficiency tends to lead to cisplatin resistance by Nox2/ROS and Nrf2/PD-L1, it is still possible that Scribble deficiency-induced PD-L1 may yield benefits in immunotherapy.

Fund

National Key R&D Program of China, Strategic Priority Research Program of the Chinese Academy of Sciences, National Natural Science Foundation of China, China Postdoctoral Science Foundation.

MLH1 enhances the sensitivity of human endometrial carcinoma cells to cisplatin by activating the MLH1/c-Abl apoptosis signaling pathway

BACKGROUND

MLH1 plays a critical role in maintaining the fidelity of DNA replication, and defects in human MLH1 have been reported. However, the role of MLH1 in endometrial carcinoma has not been fully investigated. Therefore, we aimed to study the role of MLH1 in the sensitivity of human endometrial carcinoma cells to cisplatin.

METHODS

In this study, we detected the expression of MLH1 in Ishikawa and RL95-2 cells. MLH1-siRNA and ADV-MLH1 were adopted for the silencing and overexpression of MLH1, respectively. Real-time polymerase chain reaction, Western blotting, cell proliferation assays, and cell cycle and apoptotic analyses by flow cytometry were employed to explore the underlying mechanism. A mouse xenograft model was used to investigate the effect of MLH1 on tumor growth after treatment with cisplatin.

RESULTS

Over-expression of MLH1 in Ishikawa cells dramatically increased the sensitivity of cells to cisplatin and enhanced cell apoptosis. By contrast, knockdown of MLH1 yielded the opposite effects in vitro. Mechanistically, cisplatin induced the MLH1/c-Abl apoptosis signaling pathway in ADV-MLH1-infected endometrial carcinoma cells, and these effects involved c-Abl, caspase-9, caspase-3 and PARP. Altogether, our results indicate that ADV-MLH1 might attenuate Ishikawa cell growth in vivo, resulting in increased cisplatin sensitivity.

CONCLUSIONS

MLH1 may render endometrial carcinoma cells more sensitive to cisplatin by activating the MLH1/c-Abl apoptosis signaling pathway. In addition, an applicable adenovirus vector (ADV-MLH1) for MLH1 overexpression in endometrial carcinoma was generated. Thus, ADV-MLH1 might be a novel potential therapeutic target for endometrial carcinoma.

Curcumin enhances cisplatin sensitivity of human NSCLC cell lines through influencing Cu-Sp1-CTR1 regulatory loop

BACKGROUND

Curcumin is a naturally occurring polyphenol which has been demonstrated to possess diverse biological activities. We previously reported that curcumin is a biologically active copper chelator with antitumor activity. Copper transporter 1 (CTR1) on the plasma membrane of eukaryotic cells mediates both copper as well as anticancer drug cisplatin uptake.

PURPOSE

This study aims to investigate whether curcumin enhances cisplatin sensitivity of human non-small cell lung cancer (NSCLC) through influencing Cu-Sp1-CTR1 regulatory loop.

METHODS

The combination effect of curcumin and cisplatin on cell proliferation and apoptosis was determined in vitro and in vivo. Platinum level in A549 cells and tumor tissue was measured by atomic absorption spectrometry (AAS). The binding ability of specificity protein 1 (Sp1) to CTR1 and Sp1 promoters was detected by ChIP assay and luciferase reporter assay system.

RESULTS

Here we show that combined curcumin and cisplatin treatment markedly inhibited A549 cells proliferation and induced its apoptosis. Using a mouse model of A549 xenograft, we demonstrated that curcumin inhibits copper influx and increases uptake of platinum ion in tumor. Curcumin treatment enhances the binding of Sp1 to CTR1 and Sp1 promoters, thus induces CTR1 expression and chemosensitization to cisplatin treatment. This process is regulated by the Cu-Sp1-CTR1 regulatory loop. Moreover, the enhancement mediated by curcumin on cisplatin therapeutic efficacy in cultured human NSCLC cell lines (A549, H460, H1299) was dependent on CTR1.

CONCLUSIONS

Our results demonstrated copper chelator curcumin enhances the benefits of platinum-containing chemotherapeutic agents and CTR1 could be a promising therapeutic target for non-small cell lung cancer treatment.

MicroRNA-148a-3p enhances cisplatin cytotoxicity in gastric cancer through mitochondrial fission induction and cyto-protective autophagy suppression

Cisplatin (CDDP) resistance is a major clinical problem associated with poor prognosis in gastric cancer (GC) patients. In this study, we performed integrated analysis of TCGA data from microRNAs (miRNAs) expression matrix of GC patients who received CDDP-based chemotherapy with GEO dataset which contains differential miRNAs expression profiles in CDDP-resistant and -sensitive cell lines. We identified miR-148a-3p downregulation as a key step involved in CDDP resistance. Using a cohort consisting 105 GC patients who received CDDP-based therapy, we found that miR-148a-3p downregulation was associated with a decrease in patients' disease-free survival (DFS, P = 0.0077). A series of experiment data demonstrated that: 1) miR-148a-3p was downregulated in CDDP-resistant GC cell lines; 2) miR-148a-3p reconstitution sensitized CDDP-resistant cells to CDDP treatment through promoting mitochondrial fission and decreasing AKAP1 expression level; 3) AKAP1 played a novel role in CDDP resistance by inhibiting P53-mediated DRP1 dephosphorylation; 4) miR-148a-3p reconstitution in CDDP-resistant cells inhibits the cyto-protective autophagy by suppressing RAB12 expression and mTOR1 activation. Taken together, our study demonstrates that miR-148a-3p could be a promising prognostic marker or therapeutic candidate for overcoming CDDP resistance in GC.

The functional status of DNA repair pathways determines the sensitization effect to cisplatin in non-small cell lung cancer cells

PURPOSE

Cisplatin can cause a variety of DNA crosslink lesions including intra-strand and inter-strand crosslinks (ICLs), which are associated with the sensitivity of cancer cells to cisplatin. Here, we aimed to assess the contribution of the Fanconi anemia (FA), homologous recombination (HR) and nucleotide excision repair (NER) pathways to cisplatin resistance in non-small cell lung cancer (NSCLC)-derived cells.

METHODS

The expression of FA, HR and NER pathway-associated genes was assessed by RT-qPCR and Western blotting. siRNAs were used to knock down the expression of these genes. CCK-8 and flow cytometry assays were used to assess the viability and apoptotic rate of NSCLC-derived cells, respectively. Immunofluorescence and alkaline comet assays were used to assess the repair of ICLs.

RESULTS

We found that acquired cisplatin-resistant NSCLC-derived A549/DR cells exhibited markedly enhanced FA and HR repair pathway capacities compared to its parental A549 cells and another independent NSCLC-derived cell line, Calu-1, which possesses a moderate innate resistance to cisplatin. siRNA-mediated silencing of the FA-associated genes FANCL and RAD18 and the HR-associated genes BRCA1 and BRCA2 significantly potentiated the sensitivity of A549/DR cells to cisplatin compared to A549 and Calu-1 cells, suggesting that the acquired cisplatin resistance in A549/DR cells may be attributed to enhanced FA and HR pathway capacities responsible for ICL repair. Although we found that expression knockdown of the NER-associated genes XPA and ERCC1 sensitized the three NSCLC-derived cell lines to cisplatin, the sensitization effect was more significant in Calu-1 cells than in A549 and A549/DR cells, implying that the innate cisplatin resistance in Calu-1 cells may result from an increased NER activity.

CONCLUSIONS

Our results indicate that the functional status of DNA repair pathways determine the sensitivity of NSCLC cells to cisplatin. Direct targeting of the pathway that is involved in cisplatin resistance may be an effective strategy to surmount cisplatin resistance in NSCLC.

TIMP3 regulates osteosarcoma cell migration, invasion, and chemotherapeutic resistances

Tissue inhibitors of metalloproteinases (TIMPs) inhibit matrix metalloproteinases (MMPs) to limit degradation of the extracellular matrix. Low levels of TIMP3 have been demonstrated in cancer tissues at advanced clinical stages, with positive distant metastasis and chemotherapeutic resistance. We examined the role of TIMP3 in osteosarcoma (OS) cell invasiveness and chemoresistance. TIMP3 was overexpressed or knocked down in the human OS cell lines Saos2 and MG63. Cell migration and invasion capacities were then evaluated using Transwell assays, and resistance to cisplatin was assessed by CCK-8 assay and flow cytometry. Real-time PCR and western blotting were used to investigate activation of signaling pathways downstream of TIMP3. Overexpression of TIMP3 inhibited the migration and invasion of Saos2 and MG63 cells, while knockdown of TIMP3 had the opposite effect. Cell survival after exposure to cisplatin was inhibited by TIMP3 overexpression in both Saos2 and MG63 cells. Consistently, downregulation of TIMP3 gene expression significantly decreased the sensitivity of OS cells to cisplatin treatment. MMP1, MMP2, Bcl-2, and Akt1 were all downregulated following TIMP3 overexpression, while Bax and cleaved caspase-3 were upregulated. TIMP3 knockdown had opposite effects on the regulation of these genes. Taken together, our findings suggest TIMP3 as a new target for inhibition of OS progression and chemotherapeutic resistance.

CXCR1 knockdown improves the sensitivity of osteosarcoma to cisplatin

Chemotherapy resistance is a major cause of poor prognoses for osteosarcoma patients. This study aimed to determine whether CXCR1 gene knockdown improves the sensitivity of osteosarcomas to chemotherapy. Both CXCR1 expression and cisplatin sensitivity were investigated and compared in two osteosarcoma cell lines. Sensitivity to the chemotherapy drug cisplatin and apoptosis were investigated with or without stimulation via Interleukin-8 (IL-8), which is a ligand of CXCR1. Furthermore, activation of the Akt signaling pathway was determined. Finally, luciferase-labeled CXCR1-knockdown Saos2-lung cells were injected into the tibiae of nude mice that were treated with cisplatin thereafter. We found that CXCR1 expression and cisplatin sensitivity were negatively correlated in osteosarcoma cell lines. IL-8-induced reduction in sensitivity could be blocked by silencing CXCR1, and CXCR1 knockdown suppressed the Akt signaling pathway. Moreover, CXCR1-knockdown tumors were significantly smaller than control tumors, which was consistent with the luciferase intensity results. The expression levels of IL-8, CXCR1 and p-Akt were suppressed in CXCR1-knockdown cells. Taken together, these data indicate that CXCR1 gene knockdown in osteosarcoma cells improved the sensitivity to chemotherapy and that this process might be regulated in part by the IL-8/CXCR1/Akt signaling pathway.

Defects in DNA Repair Genes Predict Response to Neoadjuvant Cisplatin-based Chemotherapy in Muscle-invasive Bladder Cancer

BACKGROUND

Cisplatin-based neoadjuvant chemotherapy (NAC) before cystectomy is the standard of care for muscle-invasive bladder cancer (MIBC), with 25-50% of patients expected to achieve a pathologic response. Validated biomarkers predictive of response are currently lacking.

OBJECTIVE

To discover and validate biomarkers predictive of response to NAC for MIBC.

DESIGN, SETTING, AND PARTICIPANTS

Pretreatment MIBC samples prospectively collected from patients treated in two separate clinical trials of cisplatin-based NAC provided the discovery and validation sets. DNA from pretreatment tumor tissue was sequenced for all coding exons of 287 cancer-related genes and was analyzed for base substitutions, indels, copy number alterations, and selected rearrangements in a Clinical Laboratory Improvements Amendments-certified laboratory.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The mean number of variants and variant status for each gene were correlated with response. Variant data from the discovery cohort were used to create a classification tree to discriminate responders from nonresponders. The resulting decision rule was then tested in the independent validation set.

RESULTS AND LIMITATIONS

Patients with a pathologic complete response had more alterations than those with residual tumor in both the discovery (p=0.024) and validation (p=0.018) sets. In the discovery set, alteration in one or more of the three DNA repair genes ATM, RB1, and FANCC predicted pathologic response (p<0.001; 87% sensitivity, 100% specificity) and better overall survival (p=0.007). This test remained predictive for pathologic response in the validation set (p=0.033), with a trend towards better overall survival (p=0.055). These results require further validation in additional sample sets.

CONCLUSIONS

Genomic alterations in the DNA repair-associated genes ATM, RB1, and FANCC predict response and clinical benefit after cisplatin-based chemotherapy for MIBC. The results suggest that defective DNA repair renders tumors sensitive to cisplatin.

PATIENT SUMMARY

Chemotherapy given before bladder removal (cystectomy) improves the chance of cure for some but not all patients with muscle-invasive bladder cancer. We found a set of genetic mutations that when present in tumor tissue predict benefit from neoadjuvant chemotherapy, suggesting that testing before chemotherapy may help in selecting patients for whom this approach is recommended.