Alcohol Metabolism Enriches Squamous Cell Carcinoma Cancer Stem Cells That Survive Oxidative Stress via Autophagy

Background: Alcohol (ethanol) consumption is a major risk factor for head and neck and esophageal squamous cell carcinomas (SCCs). However, how ethanol (EtOH) affects SCC homeostasis is incompletely understood. Methods: We utilized three-dimensional (3D) organoids and xenograft tumor transplantation models to investigate how EtOH exposure influences intratumoral SCC cell populations including putative cancer stem cells defined by high CD44 expression (CD44H cells). Results: Using 3D organoids generated from SCC cell lines, patient-derived xenograft tumors, and patient biopsies, we found that EtOH is metabolized via alcohol dehydrogenases to induce oxidative stress associated with mitochondrial superoxide generation and mitochondrial depolarization, resulting in apoptosis of the majority of SCC cells within organoids. However, CD44H cells underwent autophagy to negate EtOH-induced mitochondrial dysfunction and apoptosis and were subsequently enriched in organoids and xenograft tumors when exposed to EtOH. Importantly, inhibition of autophagy increased EtOH-mediated apoptosis and reduced CD44H cell enrichment, xenograft tumor growth, and organoid formation rate. Conclusions: This study provides mechanistic insights into how EtOH may influence SCC cells and establishes autophagy as a potential therapeutic target for the treatment of EtOH-associated SCC.

Transgelin Inhibits the Malignant Progression of Esophageal Squamous Cell Carcinomas by Regulating Epithelial–Mesenchymal Transition

ObjectiveThis article investigates the role of Transgelin (TAGLN) in the epithelial–mesenchymal transition (EMT) of esophageal squamous cell carcinomas (ESCC) and its possible mechanism of inhibiting the invasion of these cancers.MethodsTissue specimens and clinical information of patients with ESCC were collected to analyze the relationship between Transgelin expression level and prognosis of patients with ESCC. Transgelin siRNA was used to knock down Transgelin expression. The expression of Transgelin in Eca-109 and KYSE-150 cells was overexpressed by Transgelin-overexpressing plasmid. The effects of Transgelin overexpression and knockdown on the proliferation of Eca-109 and KYSE-150 cells were examined by Transwell chamber, scratch assay, and CCK-8 cell activity assay. RT-PCR and Western blot were used to detect the effect of Transgelin overexpression or knockdown on the mRNA and protein expressions of E-cadherin and Vimentin. TCGA data were used to analyze Transgelin co-expressed genes and further study the GO and KEGG enrichment analysis results under the influence of Transgelin.ResultsThe expression of Transgelin was low in ESCC, and its expression level was positively correlated with the prognosis of patients with ESCC. The targeted Transgelin siRNA and Transgelin-overexpressing plasmid can effectively regulate the expression of Transgelin mRNA and protein in Eca-109 and KYSE-150 cells. After overexpression of Transgelin, the invasion and proliferation abilities of Eca-109 and KYSE-150 cells were significantly decreased compared with those of the control group (P < 0.05). However, Transgelin knockdown could promote the proliferation, migration, and invasion of ESCC cells. The overexpression of Transgelin inhibits EMT in ESCC. With the increase of Transgelin expression in Eca-109 and KYSE-150 cells, the expression of E-cadherin increased, while the expression of Vimentin decreased, and the difference was statistically significant (P < 0.05).ConclusionTransgelin can inhibit the malignant progression of ESCC by inhibiting the occurrence of EMT.

LncRNA POU3F3 promotes melanoma cell proliferation by downregulating lncRNA MEG3

Background LncRNA POU3F3 (POU3F3) is overexpressed and plays oncogenic roles in esophageal squamous-cell carcinomas. LncRNA MEG3 (MEG3) has been characterized as a tumor suppressive lncRNA in different types of cancer. Our preliminary deep sequencing analysis revealed the inverse correlation between POU3F3 and MEG2 across melanoma tissues, indicating the interaction between them in melanoma. Therefore, this study was performed to investigate the crosstalk between POU3F3 and MEG3 in melanoma. Methods Tumor and adjacent healthy tissues collected from 60 melanoma patients were subjected to RNA extractions and RT-qPCRs to analyze the differential expression of POU3F3 and MEG2 in melanoma. In melanoma cells, POU3F3 and MEG2 were overexpressed to study the interactions between them. CCK-8 assays were performed to analyze the roles of POU3F3 and MEG2 in regulating melanoma cell proliferation. Results We found that POU3F3 was upregulated, while lncRNA MEG3 was downregulated in melanoma. Expression levels of POU3F3 and MEG3 were inversely correlated across tumor tissues. In vitro experiments showed that POU3F3 overexpression decreased MEG3 expression in melanoma cells, while MEG3 overexpression failed to affect POU3F3. POU3F3 overexpression increased melanoma cell proliferation, while MEG3 overexpression decreased melanoma cell proliferation. In addition, rescue experiments showed that MEG3 overexpression attenuated the enhancing effects of POU3F3 overexpression. Conclusion POU3F3 may promote melanoma cell proliferation by downregulating MEG3.

miR-378d Regulates Polyploidization and Malignant Phenotype of Tumor Cells Through AKT and RhoA

Studies have shown that stress such as hypoxia, chemotherapy, radiotherapy can lead to polyploidization of tumor cells, which play an important role in tumor heterogeneity and malignant phenotype. Paclitaxel (PTX) treatment promoted polyploid cancer cells (PCCs) formation, and miR-378d is sharply reduced in PCCs of esophageal squamous cell carcinomas (ESCC) cells, but miR-378d participation PCCs formation and the impact on the biological behavior of ESCC remains unclear. We analyzed the PCCs formation and biological behavior of ESCC cells in vivo and in vitro, and the related proteins regulated by miR-378d. Results showed that miR-378d expression was associated with good prognosis in ESCC patients. miR-378d inhibition promoted PCCs formation, heterogenicity, chemo-resistance, monoclonal formation, EMT, migration, invasion, stemness and metastasis of ESCC cells. miR-378d can target downregulated AKT1, and inactivating the AKT-β-catenin signaling pathway, miR-378d and AKT can also regulated RhoA expression. AKT and RhoA regulated polyploidization and depolyploidization. Therefore, miR-378d expression is a good prognostic factor of ESCC patients and regulates polyploidization and malignant phenotype of tumor cells through AKT and RhoA.

Prognostic value of visual residual tumour cells (VRTC) for patients with esophageal squamous cell carcinomas after neoadjuvant therapy followed by surgery

Background We assessed visual residual tumour cells (VRTC) with both Becker’s tumour regression grading (TRG) system and Japanese TRG system in esophageal squamous cell carcinoma (ESCC) patients treated with neoadjuvant therapy followed by surgery. Methods We compared Becker system and Japanese system in 175 ESCC patients treated between 2009 and 2015. Results According to Becker system, the 5-year DFS/DSS rates were 70.0%/89.3, 53.8%/56.7, 43.0%/49.0, and 42.4%/39.1% for TRG 1a (VRTC 0), TRG 1b (1–10%), TRG 2 (11–50%), and TRG 3 (> 50%). According to Japanese system, the rates were 38.8%/34.1, 49.5%/58.7, 50.2%/49.0 and 70.0%/89.3% for Grade 0-1a (VRTC> 66.6%), Grade 1b (33.3–66.6%), Grade 2 (1–33.3%) and Grade 3 (0). TRG according to two systems significantly discriminate the patients’ prognosis. TRG according to Becker system (HR 2.662, 95% CI 1.151–6.157), and lymph node metastasis (HR 2.567, 95% CI 1.442–4.570) were independent parameters of DSS. Conclusions Both Becker and Japanese system had their advantage in risk stratification of these ESCC patients. It was speculated that dividing 1–10% VRTC into a group might contribute to independently prognostic significance of Becker’s TRG system. Therefore, in addition to TRG of different systems, the percentage of VRTC might be recommended in the pathologic report, which could make the results more comparable among different researches, and more understandable for oncologists in the clinical practice.