Long non-coding RNA LINC00337 induces autophagy and chemoresistance to cisplatin in esophageal squamous cell carcinoma cells via upregulation of TPX2 by recruiting E2F4.

Esophageal cancer represents the eighth most frequently occurring cancer, as well as the sixth most widespread cause of cancer-related deaths. In recent years, accumulating evidence has implicated long non-coding RNAs in the progression of esophageal squamous cell carcinoma (ESCC). The aim of the present study was to investigate the potential involvement and underlying mechanisms of LINC00337 in ESCC. Expression patterns of LINC00337 and targeting protein for Xenopus kinesin-like protein 2 (TPX2) in ESCC tissues and cells were detected using RT-qPCR and immunohistochemical staining. Next, the interactions among LINC00337, E2F4, and TPX2 were identified using chromatin immunoprecipitation, dual-luciferase reporter, and RNA-binding protein immunoprecipitation assays, suggesting that LINC00337 could recruit E2F4 to enhance the transcription of TPX2. Thereafter, the regulatory roles of LINC00337 and TPX2 in ESCC were analyzed by altering the expression of LINC00337 or TPX2 in ESCC cells following treatment with cisplatin (DDP). The levels of autophagy-related proteins Beclin1 and LC3II/LC3I, viability, autophagy, apoptosis, and chemoresistance of ESCC cells to DDP were measured following transfection treatment with different plasmids. Additionally, the role of the LINC00337/E2F4/TPX2 axis was assessed in vivo by measuring tumor formation in nude mice. The results demonstrated that LINC00337 upregulated TPX2, consequently leading to elevated levels of Beclin1 and LC3II/LC3I, promoted cell viability and autophagy, while inhibiting apoptosis and chemosensitivity to DDP in ESCC. In sum, the current study evidenced that the overexpression of LINC00337 could potentially enhance ESCC cell autophagy and chemoresistance to DDP via the upregulation of TPX2 by recruiting E2F4. Thus, LINC00337 may serve as a potential candidate for the treatment of ESCC.

Yang C ，Shen S ，Zheng X ，Ye K ，Ge H ，Sun Y ，Lu Y ... -  《-》

Downregulation of ALDH5A1 suppresses cisplatin resistance in esophageal squamous cell carcinoma by regulating ferroptosis signaling pathways.

This study explores the specific role and underlying mechanisms of ALDH5A1 in the chemoresistance of esophageal squamous cell carcinoma (ESCC). The levels of cleaved caspase-3, 4-hydroxynonenal (4-HNE), intracellular Fe2+, and lipid reactive oxygen species (ROS) were evaluated via immunofluorescence. Cell viability and migration were quantified using cell counting kit-8 assays and wound healing assays, respectively. Flow cytometry was utilized to analyze cell apoptosis and ROS production. The concentrations of malondialdehyde (MDA) and reduced glutathione were determined by enzyme-linked immunosorbent assay. Proteome profiling was performed using data-independent acquisition. Additionally, a xenograft mouse model of ESCC was established to investigate the relationship between ALDH5A1 expression and the cisplatin (DDP)-resistance mechanism in vivo. ALDH5A1 is overexpressed in both ESCC patients and ESCC/DDP cells. Silencing of ALDH5A1 significantly enhances the inhibitory effects of DDP treatment on the viability and migration of KYSE30/DDP and KYSE150/DDP cells and promotes apoptosis. Furthermore, it intensifies DDP's suppressive effects on tumor volume and weight in nude mice. Gene ontology biological process analysis has shown that ferroptosis plays a crucial role in both KYSE30/DDP cells and KYSE30/DDP cells transfected with si-ALDH5A1. Our in vitro and in vivo experiments demonstrate that DDP treatment promotes the accumulation of ROS, lipid ROS, MDA, LPO, and intracellular Fe2+ content, increases the levels of proteins that promote ferroptosis (ACSL4 and FTH1), and decreases the expression of anti-ferroptosis proteins (SLC7A11, FTL, and GPX4). Silencing of ALDH5A1 further amplifies the regulatory effects of DDP both in vitro and in vivo. ALDH5A1 potentially acts as an oncogene in ESCC chemoresistance. Silencing of ALDH5A1 can reduce DDP resistance in ESCC through promoting ferroptosis signaling pathways. These findings suggest a promising strategy for the treatment of ESCC in clinical practice.

Song K ，Ma C ，Maswikiti EP ，Gu B ，Wang B ，Wang N ，Jiang P ，Chen H ... -  《-》

MicroRNA-153-3p regulates cell proliferation and cisplatin resistance via Nrf-2 in esophageal squamous cell carcinoma.

Our recent studies have indicated that miR-153-3p is downregulated in the esophageal squamous cell carcinoma (ESCC) cell lines and tissues. Upregulation of miR-153-3p was found to inhibit migration and invasion of ESCC cells. However, whether miR-153-3p regulates the cisplatin sensitivity in ESCC cells remains unclear. In this study, we explored whether and how miR-153-3p regulates the proliferation and confers cisplatin resistance in ESCC by targeting the Nrf-2 protein. Eca109 cell line was transfected with microRNA-153-3p mimics or Nrf-2siRNA and cell proliferation and cisplatin resistance were studied. A dual-luciferase reporter assay was performed on Eca109 cells cotransfected with the wild-type/mutant 3'UTR sequences of Nrf-2 and control or microRNA-153-3p mimics. We determined the correlation between microRNA-153-3p and Nrf-2 expression in human ESCC samples and explored the effect of Nrf-2 in the overall survival rate of ESCC patients. MiR-153-3p significantly suppressed cell proliferation and increased the sensitivity of Eca-109 cells to cisplatin. MiR-153-3p showed a negative correlation with Nrf-2 in human esophageal carcinoma tissues. MiR-153-3p suppressed the expression of Nrf-2 via binding to its 3'-UTR region. Furthermore, inhibition of Nrf-2 also decreased cell proliferation and increased the sensitivity of Eca109 cells to cisplatin. High expression of Nrf-2 in human ESCC samples was associated with poor overall survival of ESCC patients. MiR-153-3p inhibits cell proliferation and confers cisplatin resistance by downregulating Nrf-2 expression in Eca-109 cells. Thus, miR-153-3p/Nrf-2 may play an important role in conferring cisplatin resistance in ESCC. Nrf-2 appears to be a promising therapeutic target for ESCC.

Zuo J ，Zhao M ，Fan Z ，Liu B ，Wang Y ，Li Y ，Lv P ，Xing L ，Zhang X ，Shen H ... -  《-》

Circular RNA hsa_circ_0000277 promotes tumor progression and DDP resistance in esophageal squamous cell carcinoma.

Circular RNAs (circRNAs) are well-known regulators of cancer progression and chemoresistance in various types of cancers. This study was performed to investigate the function of hsa_circ_0000277 in esophageal squamous cell carcinoma (ESCC). RNA levels were analyzed via the reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Cell Counting Kit-8 (CCK-8) assay was applied to determine cell proliferation and half maximal inhibitory concentration (IC50) of cisplatin (DDP). Colony formation ability was evaluated by colony formation assay. Cell cycle and apoptosis were measured using flow cytometry. RNA immunoprecipitation (RIP), pull-down assay and dual-luciferase reporter assays were performed for target interaction analysis. The protein levels were determined through western blot. Xenograft models were established for researching hsa_circ_0000277 function in vivo. Hsa_circ_0000277 expression was increased in ESCC cells and tissues, and it had important clinical significance. Downregulation of hsa_circ_0000277 repressed ESCC cell proliferation, colony formation, cell cycle, and DDP resistance. Hsa_circ_0000277 acted as a microRNA-873-5p (miR-873-5p) sponge and Sry-related high-mobility group box 4 (SOX4) was validated as a target of miR-873-5p. Moreover, hsa_circ_0000277/miR-873-5p axis and miR-873-5p/SOX4 axis regulated ESCC cell progression and DDP resistance. Hsa_circ_0000277/miR-873-5p axis activated SOX4/Wnt/β-catenin signaling pathway. Hsa_circ_0000277 facilitated tumorigenesis and DDP resistance by miR-873-5p/SOX4 axis in vivo. These findings unraveled that hsa_circ_0000277 promoted ESCC progression and DDP resistance via miR-873-5p/SOX4/Wnt/β-catenin axis, showing a specific molecular mechanism of carcinogenesis and chemoresistance in ESCC.

Cheng J ，Zhang R ，Yan M ，Li Y ... -  《BMC CANCER》

Circular RNA circNTRK2 facilitates the progression of esophageal squamous cell carcinoma through up-regulating NRIP1 expression via miR-140-3p.

Chen X ，Jiang J ，Zhao Y ，Wang X ，Zhang C ，Zhuan L ，Zhang D ，Zheng Y ... -  《JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH》