CXCL6 fuels the growth and metastases of esophageal squamous cell carcinoma cells both in vitro and in vivo through upregulation of PD-L1 via activation of STAT3 pathway.

CXCL6, contraction of C-X-C motif chemokine ligand 6, whose biological roles have been rarely described in esophageal squamous cell carcinoma (ESCC). To understand the clinicopathological and biological roles played by CXCL6 in the growth and metastasis of ESCC, immunohistochemistry was used to detect the expression of CXCL6 in ESCC tissues, totaling 105 cases; and the correlation was statistically analyzed between CXCL6 expression and clinicopathological parameters. The role mediated in migration and invasion was evaluated using wound-healing and Transwell assays. MTT and flow cytometry were used to assay the proliferative variation. In vivo, tail vein injection model was established in nude mice xenografted with human ESCC cell lines whose CXCL6 were artificially manipulated. It was found that relative to normal control, CXCL6 was profoundly higher in ESCC; upregulated CXCL6 only significantly correlated with differentiation degree. In vitro, CXCL6 was found to promote the proliferation, migration, and invasion of ESCC cells; which was fully corroborated by nude mice experiment that CXCL6 can promote the growth and metastases of ESCC cells in vivo. Mechanistically, CXCL6 was discovered to be capable of promoting epithelial-mesenchymal transition and upregulating PD-L1 expression through activation of the STAT3 pathway. Collectively, all the data we showed here demonstrate that CXCL6 can enhance the growth and metastases of ESCC cells both in vivo and in vitro.

CALM1 promotes progression and dampens chemosensitivity to EGFR inhibitor in esophageal squamous cell carcinoma.

BACKGROUND: Calmodulin1 (CALM1) has been identified as one of the overexpression genes in a variety of cancers and EGFR inhibitor have been widely used in clinical treatment but it is unknown whether CALM1 and epidermal growth factor receptor (EGFR) have a synergistic effect in esophageal squamous cell carcinoma (ESCC). The aim of the present study was to explore the synergistic effects of knock-out CALM1 combined with EGFR inhibitor (Afatinib) and to elucidate the role of CALM1 in sensitizing the resistance to Afatinib in ESCC. METHOD: Immunohistochemistry (IHC) and qRT-PCR were used to examine the expression of CALM1 and EGFR in ESCC tissues. Kaplan-Meier survival analysis was used to analyze the clinical and prognostic significance of CALM1 and EGFR expression in ESCC. Furthermore, to evaluate the biological function of CALM1 in ESCC, the latest gene editing technique CRISPR/Cas9(Clustered regularly interspaced short palindromic repeats)was applied to knockout CALM1 in ESCC cell lines KYSE150, Eca109 and TE-1. MTT, flow cytometry, Transwell migration, scratch wound-healing and colony formation assays were performed to assay the combined effect of knock-out CALM1 and EGFR inhibitor on ESCC cell proliferation and migration. In addition, nude mice xenograft model was used to observe the synergistic inhibition of knock-out CALM1 and Afatinib. RESULTS: Both CALM1 and EGFR were found to be significantly over-expressed in ESCC compared with paired normal control. Over-expressed CALM1 and EGFR were significantly associated with clinical stage, T classification and poor overall prognosis, respectively. In vitro, the combined effect of knock-out CALM1 mediated by the lentivirus and EGFR inhibitor was shown to be capable of inhibiting the proliferation, inducing cell cycle arrest at G1/S stage and increasing apoptosis of KYSE-150 and Eca109 cells; invasion and migration were also suppressed. In vivo, the results of tumor weight and total fluorescence were markedly reduced compared with the sgCtrl-infected group and sgCAML1 group. CONCLUSION: Our data demonstrated that knock-out of CALM1 could sensitize ESCC cells to EGFR inhibitor, and it may exert oncogenic role via promotion of EMT. Taken together, CALM1 may be a tempting target to overcome Afatinib resistance.

[Corrigendum] Plasma­derived exosomal pyruvate kinase isoenzyme type M2 accelerates the proliferation and motility of oesophageal squamous cell carcinoma cells.

Subsequently to the publication of the above article, the authors have realized that Fig. 5B on p. 8 was compiled erroneously, in the sense that the two immunohistochemical images selected for Fig 5B did not correspond to each other, meaning they were not derived from the same field under the microscope. This error was inadvertently made during the preparation of the manuscript. A corrected version of Fig. 5, showing the correct data for the expression of PKM2 in NAT in Fig. 5B, is shown on the next page. This inadvertent error did not affect the conclusions reported in this paper, and all the authors agree with this Corrigendum. The authors sincerely thank the Editor of Oncology Reports for presenting them with the opportunity to publish this Corrigendum, and apologize to the readership of the journal for any inconvenience caused. [the original article was published in Oncology Reports 46: Article no. 216, 2021; DOI: 10.3892/or.2021.8167].

Proteomic profiling of plasma exosomes reveals CD82 involvement in the development of esophageal squamous cell carcinoma.

The Xinjiang Uygur autonomous region has a high incidence of esophageal cancer. For the early diagnosis of patients with esophageal squamous cell carcinoma (ESCC), exosomes were isolated and quantified by liquid chromatography tandem mass spectrometry ((LC-MS/MS) with data independent acquisition (DIA) from the peripheral blood of patients with benign esophageal disease (BED), esophageal intraepithelial neoplasia (EIN) and ESCC. A total of 1117 proteins were identified in the above 9 samples. The proteomic results showed that the quantity of CD82 in exosomes of EIN was significantly higher than that in patients with BED and ESCC. Meanwhile, our ELISA test verified our proteomic results. In addition, the immunohistochemical results showed high CD82 expression in adjacent normal tissues and low expression in ESCC tissues. CD82 expression in ESCC tissues was negatively correlated with tumor stage and the expression of PKM2, and the high expression of CD82 combined with low expression of PKM2 in ESCC tissues suggested a good prognosis. To further clarify the tumor suppressive mechanism of CD82, the TIMER and TISDB databases were analyzed, and CD82 expression in tumor tissues was found to be related to the infiltration of immune cells. CD82 in exosomes is involved in the development of ESCC. SIGNIFICANCE: Xinjiang is a high incidence area of ESCC. When diagnosed in the middle and late stages of the disease, the prognosis of patients is poor. Exosomes provide the possibility of relatively noninvasive and early detection of esophageal carcinogenesis. To the best of our knowledge, this was the first study using the DIA technique to analyze the exosomal proteins of patients with different stages of ESCC. The proteins identified in the exosomes in these three groups could provide insights for understanding how exosomes promote the occurrence of ESCC, the antitumour mechanism of humans and the early diagnosis of ESCC.

The expression and activation of ERK/MAPK pathway in human esophageal cancer cell line EC9706.

While there have been more and more studies concerning mitogen-activated protein kinases (MAPKs) signaling pathways, which control many cellular complex programmes, such as cell proliferation, differentiation, cell death and embryogenesis. However, few studies are carried out about expression and activation of classical MAPKs, extracellular signal-regulated kinase1/2 (ERK1/2) in human esophageal cancer cell line. Therefore, in the present study, we investigated the expression and activation of ERK1/2 in human esophageal cancer cell line EC9706 and human normal esophageal epithelial cell line Heepic, which is as control. This study showed that ERK1/2 was transiently phosphorylated both in EC9706 and Heepic, the kinetics of which were slightly different. To further study the ERK/MAPK signaling pathway in EC9706 and Heepic cell line, U0126 a kind of specific inhibitor of MEK was used. This study showed that U0126 can block the phosphorylation of ERK1/2 in a short time, the complete inhibition concentration for EC9706 and Heepic cell line is 50 and 20 µM, respectively. Incidentally, to further investigate the different roles of ERK1 and ERK2, vector-based short hairpin interference vectors targeted on ERK1/2 was constructed. Moreover, the effective interference target sequence was screened out in a transient transfection manner. MTT experiment showed that ERK2 is more important than ERK1 in the proliferation of EC9706 cells.

Plasma­derived exosomal pyruvate kinase isoenzyme type M2 accelerates the proliferation and motility of oesophageal squamous cell carcinoma cells.

Exosomal pyruvate kinase isoenzyme type M2 (PKM2) has been found to play a key role in the progression of human hepatocarcinoma. However, exosomal PKM2 (especially plasma­derived exosomal PKM2), in patients with oesophageal squamous cell carcinoma (ESCC) has not been well defined. In the present study, plasma­derived exosomes were isolated from healthy controls and patients with ESCC, and identified by transmission electronic microscopy, western blotting, nano­flow cytometry, nanoparticle tracking and phagocytosis analysis; exosomal PKM2 was detected by western blotting and ELISA. In addition, changes in cellular proliferation and motility in recipient cells (Eca109) were assessed using Cell Counting Kit­8, colony formation, wound­healing and Transwell assays. The PKM2 content was higher in exosomes from patients with ESCC than in those from healthy donors. Furthermore, exosomes from patients with ESCC enhanced the proliferation and motility of ESCC cells in vitro. Notably, PKM2 was found to be transferred by exosomes, and was able to act by activating STAT3. To verify the association between PKM2 and STAT3, immunohistochemistry was employed to analyse the protein levels of PKM2 and pSTAT3Tyr705. These data revealed that PKM2 and pSTAT3Tyr705 were upregulated and associated with overall survival in patients with ESCC. Therefore, the present study highlights that exosomes from patients with ESCC enhance the migration and invasiveness of ESCC cells by transferring PKM2.

Prognostic significance of pyruvate kinase M2 expression in esophageal squamous cell carcinoma and its meta-analysis.

BACKGROUND: Pyruvate kinase 2 (PKM2) is a key enzyme in the glycolysis pathway and has been reported to be associated with the development of esophageal squamous cell carcinoma (ESCC). However, the prognostic value of PKM2 in ESCC remains undetermined. METHODS: This study aimed to investigate the clinicopathological significance of PKM2 expression in ESCC. A comprehensive and systematic literature search was conducted using the PubMed, Embase, Medline, and Cochrane library databases. The quality of studies and potential for bias were appraised, and meta-analysis was performed to assess the prognostic impact of PKM2 on overall survival (OS). RESULTS: A total of 5 studies with 781 participants were eligible and enrolled. Patients with high PKM2 expression were associated with poor prognosis in ESCC [hazard ratio (HR) =1.72, 95% confidence interval (CI): 1.41-2.09; P<0.01]. Furthermore, upregulated PKM2 was significantly associated with lymph node metastasis [odds ratio (OR) =2.38, 95% CI: 1.68-3.35; P<0.01], clinical stage (OR =3.29, 95% CI: 2.27-4.77; P<0.01), and tumor (T) classification (OR =2.92, 95% CI: 2.05-4.16, P<0.01). DISCUSSION: High PKM2 expression denotes worse OS in ESCC patients, and correlates with the lymph node metastasis, clinical stage, and T classification. However, further studies are warranted to assess how PKM2 can be implemented as a reliable staging element in clinical practice and whether it could provide a new target for therapeutic intervention.

Effects of propranolol and isoproterenol on infantile hemangioma endothelial cells in vitro.

The aim of the present study was to investigate the effects of propranolol and isoproterenol on the growth curve of infantile hemangioma endothelial cells (IHECs) in vitro and determine the functions of the ß-adrenergic receptor in the pathogenesis of infantile hemangioma. IHECs were divided into three groups: The control group, the propranolol group (PG) and the isoproterenol group (IG). The PG and IG were administered with high, medium and low concentrations of the corresponding drugs. The cell growth in each group was determined using the MTT assay. A high propranolol concentration resulted in the inhibition of cell growth. By comparison, isoproterenol promoted cell growth. Within a specific time-frame (72-96 h), high drug concentrations (20 µg/ml) elicited strong effects on the cells. At certain concentrations, propranolol inhibited cell growth once the proliferation stage of IHECs had been affected for a specific length of time, whereas isoproterenol yielded opposite results. The ß-adrenergic receptor elicits an important effect in the pathogenesis of infantile hemangioma.