SOX17 overexpression sensitizes chemoradiation response in esophageal cancer by transcriptional down-regulation of DNA repair and damage response genes

Regulation of AUF1 alternative splicing by hnRNPA1 and SRSF2 modulate the sensitivity of ovarian cancer cells to cisplatin

PURPOSE

Clarification of cisplatin resistance may provide new targets for therapy in cisplatin resistant ovarian cancer. The current study aims to explore involvement of isoforms of AU-rich element RNA-binding protein 1 (AUF1) in cisplatin resistance in ovarian cancer.

METHODS

The cancer stem cell-like features were analyzed using colony formation assay, tumor sphere formation assay and nude mouse xenograft experiments. AUF1 isoforms expression was analyzed using immunoblotting, qRT-PCR, and immunohistochemistry. RIP and Biotin pulldown was used to analyze the interaction of SRSF2 and hnRNPA1 with AUF1 transcript. Transcriptome regulated by AUF1 isoforms was analyzed by RNA-seq.

RESULTS

The current study demonstrated differential expression of AUF1 isoforms in cisplatin sensitive and resistant ovarian cancer tissues and cells. P37 isoform promoted proliferation, while p45 isoform enhanced responsiveness of ovarian cancer cells to cisplatin. the clonal formation capacity of the cells, and the restoration of p45 expression reduced the capacity with cisplatin treatment. The competitive binding of phosphorylated hnRNPA1 and O-GlcNAc-modified SRSF2 on AUF1 exon 2 and exon 7 regulated the alternative splicing of AUF1.

CONCLUSION

The competitive binding of phosphorylated hnRNPA1 and O-GlcNAc modified SRSF2 on exon 2 and exon 7 regulated the alternative splicing of AUF1 and subsequent isoform expression. P37 isoform played a "cancer promoter" role, p42 and p45, especially p45 played a "cancer suppressor" role in ovarian cancer. This study provides a new target for exploring the drug resistance mechanism of ovarian cancer.

SOX17 expression in ovarian clear cell carcinoma

Recent studies have revealed that the Sry-related HMG box gene 17 (SOX17) plays an important role in ovarian carcinogenesis. Unlike other types of ovarian cancer, ovarian clear cell carcinoma (OCCC) has a distinct pathobiological phenotype, often harboring an AT-rich interaction domain 1 A (ARID1A) mutation. In the present study, to determine the SOX17 in OCCC cells, we immunohistochemically examined SOX17 expression in 47 whole-tissue specimens of OCCC. Although not statistically significant, SOX17-high immunoreactivity tended to be related to unfavorable patient outcomes. We also aimed to determine the relationship of SOX17 with ARID1A. Double immunofluorescence staining demonstrated that SOX17 immunoreactivity was not associated with ARID1A immunoreactivity. Immunoblotting revealed that SOX17 was abundantly expressed in cultured OVISE and RMG-V OCCC cells, but not in OVTOKO OCCC cells. Polyubiquitinated bands of SOX17 were observed in MG132 treated OVTOKO, but not in OVISE or RMG-V OCCC cells. Notably, si-RNA-mediated knockdown of a deubiquitinase enzyme, ubiquitin C-terminal hydrolase L1, increased polyubiquitination followed by proteasome degradation of SOX17 in OVISE. These findings indicate that SOX17 is not uniformly and heterogeneously expressed in OCCCs, independent of ARID1A deficiency. Impaired ubiquitin-mediated proteasome degradation may stabilize SOX17 in some OCCC cells.

Cell-intrinsic platinum response and associated genetic and gene expression signatures in ovarian cancer cell lines and isogenic models

Ovarian cancers are still largely treated with platinum-based chemotherapy as the standard of care, yet few biomarkers of clinical response have had an impact on clinical decision making as of yet. Two particular challenges faced in mechanistically deciphering platinum responsiveness in ovarian cancer have been the suitability of cell line models for ovarian cancer subtypes and the availability of information on comparatively how sensitive ovarian cancer cell lines are to platinum. We performed one of the most comprehensive profiles to date on 36 ovarian cancer cell lines across over seven subtypes and integrated drug response and multiomic data to improve on our understanding of the best cell line models for platinum responsiveness in ovarian cancer. RNA-seq analysis of the 36 cell lines in a single batch experiment largely conforms with the currently accepted subtyping of ovarian cancers, further supporting other studies that have reclassified cell lines and demonstrate that commonly used cell lines are poor models of high-grade serous ovarian carcinoma. We performed drug dose response assays in the 32 of these cell lines for cisplatin and carboplatin, providing a quantitative database of IC50s for these drugs. Our results demonstrate that cell lines largely fall either well above or below the equivalent dose of the clinical maximally achievable dose (Cmax) of each compound, allowing designation of cell lines as sensitive or resistant. We performed differential expression analysis for high-grade serous ovarian carcinoma cell lines to identify gene expression correlating with platinum-response. Further, we generated two platinum-resistant derivatives each for OVCAR3 and OVCAR4, as well as leveraged clinically-resistant PEO1/PEO4/PEO6 and PEA1/PEA2 isogenic models to perform differential expression analysis for seven total isogenic pairs of platinum resistant cell lines. While gene expression changes overall were heterogeneous and vast, common themes were innate immunity/STAT activation, epithelial to mesenchymal transition and stemness, and platinum influx/efflux regulators. In addition to gene expression analyses, we performed copy number signature analysis and orthogonal measures of homologous recombination deficiency (HRD) scar scores and copy number burden, which is the first report to our knowledge applying field-standard copy number signatures to ovarian cancer cell lines. We also examined markers and functional readouts of stemness that revealed that cell lines are poor models for examination of stemness contributions to platinum resistance, likely pointing to the fact that this is a transient state. Overall this study serves as a resource to determine the best cell lines to utilize for ovarian cancer research on certain subtypes and platinum response studies, as well as sparks new hypotheses for future study in ovarian cancer.

SIRT1 Promotes Chemoradiotherapy Resistance in Esophageal Squamous Cell Carcinoma

INTRODUCTION

Identifying accurate biomarkers for predicting response to chemoradiotherapy (CRT) in patients with esophageal squamous cell carcinoma (ESCC) is a critical challenge. The protein SIRT1, recognized for its implications in longevity, has been associated with tumor promotion in ESCC. However, data regarding its correlation with CRT sensitivity remain unreported. Therefore, in this study, we aimed to investigate the relationship between SIRT1 expression and CRT sensitivity and concurrently assess the effect of SIRT1 knockdown on CRT sensitivity in ESCC.

METHODS

This study included 73 patients who underwent radical esophagectomy after CRT. SIRT1 expression in pre-treatment endoscopic biopsies was assessed through immunostaining, followed by a comparative analysis of CRT effects on surgical specimens. Small interfering RNA was used to attenuate SIRT1 expression in TE5 and TE10 cells, which were then subjected to cisplatin treatment at varying doses and concentrations and irradiation with X-rays, respectively.

RESULTS

High SIRT1 tissue expression was significantly associated with CRT resistance. Multivariate analysis identified high SIRT1 expression as an independent biomarker for poor CRT response. In TE-5 and TE-10 cells, SIRT1 knockdown significantly decreased cell viability and increased sensitivity to cisplatin and radiation treatment compared to that of the negative control.

CONCLUSION

Our study results demonstrate the potential of SIRT1 as a predictive biomarker for CRT response in ESCC, highlighting the heightened sensitivity to CRT upon the transcriptional inactivation of SIRT1. Targeting SIRT1 emerges as a promising strategy for enhancing the efficacy of CRT for ESCC.

Identification of a prognostic DNA repair gene signature in esophageal cancer

Background

DNA repair plays a crucial role in the development and progression of different types of cancers. Nevertheless, little is known about the role of DNA repair-related genes (DRRGs) in esophageal cancer (EC). The present study aimed to identify a novel DRRGs prognostic signature in EC.

Methods

Gene set enrichment analysis (GSEA) was performed to screen 150 genes related to DNA repair, which is the most important enrichment gene set in EC. Univariate and multivariate Cox regression analyses were used to screen DRRGs closely associated with prognosis. The difference in the expression of hub DRRGs between tumor and normal tissues was analyzed. Combined with clinical indicators (including age, gender, and tumor stage), we evaluated whether the 4-DRRGs signature was an independent prognostic factor. In addition, we evaluated the prediction accuracy using a receiver operating characteristic (ROC) curve and visualized the model's performance via a nomogram.

Results

Four-DRRGs (NT5C3A, TAF9, BCAP31, and NUDT21) were selected by Cox regression analysis to establish a prognostic signature to effectively classify patients into high- and low-risk groups. The area under the curve (AUC) of the time-dependent ROC of the prognostic signature for 1- and 3-year was 0.769 and 0.720, respectively. Compared with other clinical characteristics, the risk score showed a robust ability to predict the prognosis in EC, especially in the early stage of EC. Furthermore, we constructed a nomogram to interpret the clinical application of the 4-DRRGs signature.

Conclusions

In conclusion, we identified a prognostic signature based on the DRRGs for patients with EC, which can contribute independent value in identifying clinical outcomes that complement the TNM system in EC.

Pan-cancer Analysis Reveals Cancer-dependent Expression of SOX17 and Associated Clinical Outcomes

BACKGROUND/AIM

SRY-box containing gene 17 (SOX17) plays a pivotal role in cancer onset and progression and is considered a potential target for cancer diagnosis and treatment. However, the expression pattern of SOX17 in cancer and its clinical relevance remains unknown. Here, we explored the relationship between the expression of SOX17 and drug response by examining SOX17 expression patterns across multiple cancer types.

MATERIALS AND METHODS

Single-cell and bulk RNA-seq analyses were used to explore the expression profile of SOX17. Analysis results were verified with qPCR and immunohistochemistry. Survival, drug response, and co-expression analyses were performed to illustrate its correlation with clinical outcomes.

RESULTS

The results revealed that abnormal expression of SOX17 is highly heterogenous across multiple cancer types, indicating that SOX17 manifests as a cancer type-dependent feature. Furthermore, the expression pattern of SOX17 is also associated with cancer prognosis in certain cancer types. Strong SOX17 expression correlates with the potency of small molecule drugs that affect PI3K/mTOR signaling. FGF18, a gene highly relevant to SOX17, is involved in the PI3K-AKT signaling pathway. Single-cell RNA-seq analysis demonstrated that SOX17 is mainly expressed in endothelial cells and barely expressed in other cells but spreads to other cell types during the development of ovarian cancer.

CONCLUSION

Our study revealed the expression pattern of SOX17 in pan-cancer through bulk and single-cell RNA-seq analyses and determined that SOX17 is related to the diagnosis, staging, and prognosis of some tumors. These findings have clinical implications and may help identify mechanistic pathways amenable to pharmacological interventions.

Nutlin-3 acts as a DNA methyltransferase inhibitor to sensitize esophageal cancer to chemoradiation

Esophageal squamous cell carcinoma (ESCC) is highly resistant to chemoradiation therapy. We aimed to examine whether Nutlin-3, a molecule that suppresses murine double min 2 (MDM2)-mediated p53 and Retinoblastoma (RB) protein degradation leading to downregulation of DNA methyltransferases (DNMTs), can be a novel therapeutic agent for ESCC. We used wild-type and chemoradiation-resistant ESCC cell lines in this study. The expression of DNMTs, p53 and RB, and methylation level of tumor suppressor genes (TSG) were analyzed upon Nutlin-3 treatment. The antitumor efficacy of Nutlin-3 was investigated in ESCC cell lines and xenograft tumor model. TSG protein expression was checked in the excised tumor tissue. Nutlin-3 induced upregulation of p53 and RB and downregulation of DNMTs proteins in the chemoradiation-resistant and aggressive ESCC cells. The methylation level of TSGs was decreased by Nutlin-3. Nutlin-3 inhibits clonogenic growth of ESCC cells and exerts a synergistic cytotoxic-effect when combined with chemotherapeutic agent cisplatin. Moreover, xenograft tumor growth in SCID mice was suppressed by Nutlin-3. The protein expression level of DNMTs was downregulated, and that of TSGs was upregulated by Nutlin-3 treatment in the excised tumor tissue. In conclusion, Nutlin-3 is a potential therapeutic agent that can potentiate the treatment efficacy of chemoradiation-resistant ESCC.

Drug Repurposing Applications to Overcome Male Predominance via Targeting G2/M Checkpoint in Human Esophageal Squamous Cell Carcinoma

Esophageal squamous cell carcinoma (ESCC) is strongly characterized by a male predominance with higher mortality rates and worse responses to treatment in males versus females. Despite the role of sex hormones, other causes that may contribute to sex bias in ESCC remain largely unknown, especially as age increases and the hormone difference begins to diminish between sexes. In this study, we analyzed genomics, transcriptomics, and epigenomics from 663 ESCC patients and found that G2/M checkpoint pathway-related sex bias and age bias were significantly present in multi-omics data. In accordance with gene expression patterns across sexes, ten compounds were identified by applying drug repurposing from three drug sensitivity databases: The Connective Map (CMap), Genomics of Drug Sensitivity in Cancer (GDSC), and The Cancer Therapeutic Response Portal (CTRP). MK1775 and decitabine showed better efficacy in two male ESCC cell lines in vitro and in vivo. The drugs' relevance to the transition between G2 and M was especially evident in male cell lines. In our study, we first validated the sex bias of the G2/M checkpoint pathway in ESCC and then determined that G2/M targets may be included in combination therapy for male patients to improve the efficacy of ESCC treatment.

Dysregulation of SOX17/NRF2 axis confers chemoradiotherapy resistance and emerges as a novel therapeutic target in esophageal squamous cell carcinoma

Background

Esophageal squamous cell carcinoma (ESCC) is the sixth leading cause of cancer-associated death worldwide with a dismal overall 5-year survival rate of less than 20%. The standard first-line therapy for advanced ESCC is concomitant chemo-radiation therapy (CCRT); however, patients usually develop resistance, resulting in unfavorable outcomes. Therefore, it is urgent to identify the mechanisms underlying CCRT resistance and develop effective treatment strategies.

Methods

Patients’ endoscopic biopsy tumor tissues obtained before CCRT treatment were used to perform RNA-seq and GSEA analysis. Immunohistochemical (IHC) staining, chromatin immunoprecipitation (ChIP), and promoter reporter analyses were conducted to investigate the relationship between SOX17 and NRF2. Xenograft mouse models were used to study the role of SOX17/NRF2 axis in tumor growth and the efficacy of carboxymethyl cellulose-coated zero-valent-iron (ZVI@CMC).

Results

In this study, a notable gene expression signature associated with NRF2 activation was observed in the poor CCRT responders. Further, IHC staining of endoscopic biopsy of 164 ESCC patients revealed an inverse correlation between NRF2 and SOX17, a tumor-suppressive transcription factor with low expression in ESCC due to promoter hypermethylation. Using ChIP and promoter reporter analyses, we demonstrated that SOX17 was a novel upstream transcriptional suppressor of NRF2. In particular, SOX17^low/NRF2^high nuclear level significantly correlated with poor CCRT response and poor survival, indicating that the dysregulation of SOX17/NRF2 axis played a pivotal role in CCRT resistance and tumor progression. Notably, the in-house developed nanoparticle ZVI@CMC functioned as an inhibitor of DNA methyltransferases to restore expression of SOX17 that downregulated NRF2, thereby overcoming the resistance in ESCC. Additionally, the combination of ZVI@CMC with radiation treatment significantly augmented anticancer efficacy to inhibit tumor growth in CCRT resistant cancer.

Conclusion

This study identifies a novel SOX17^low/NRF2^high signature in ESCC patients with poor prognosis, recognizes SOX17 as a transcriptional repressor of NRF2, and provides a promising strategy targeting SOX17/NRF2 axis to overcome resistance.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12929-022-00873-4.

LOX and Its Methylation Impact Prognosis of Diseases and Correlate with TAM Infiltration in ESCA

Background

ESCA is one of the digestive tract tumors with a high fatality. It is implicated in an intricate gene regulation process, but the pathogenesis remains ambiguous.

Methods

The study used the packages of Limma from R software to analyze DEGs of ESCA in the GEO database and TCGA database. We employed the DAVID website for enrichment analysis, and the string database constructed the PPI network. Hub genes were identified from ESCA DEGs with Cytoscape MCODE. We evaluated the clinical relevance of LOX expression and its DNA methylation in the cBioPortal database and explored the roles of LOX in ESCA immunity, especially immune cell infiltration levels and immune checkpoint expression, by immunedeconv package of R software.

Conclusions

The overexpression of LOX in ESCA is regulated by DNA hypomethylation; LOX overexpression or LOX hypomethylation can predict a worse prognosis in patients with ESCA. Besides, LOX may be involved in TIME regulation, promoting the infiltration levels and function of TAM. Hence, high LOX expression affected by DNA hypomethylation has an essential role in patients with ESCA, which may become an effective prognostic marker and therapeutic target.

The Biomarker Like the Correlation between Vasculogenic Mimicry, Vascular Endothelial Cadherin, Sex-DeterminingRegion on Y-Box Transcription Factor 17, and Cyclin D1 in Oesophageal Squamous Cell Carcinoma

Background

This study aimed to explore the relationships between the sex-determining region on Y (SRY) box transcription factor 17 (SOX17), Cyclin D1, vascular endothelial cadherin (VE-cadherin), and vasculogenic mimicry (VM) in the occurrence and development of esophageal squamous cell carcinoma (ESCC).

Methods

The expressions of SOX17, Cyclin D1, and VE-cadherin, as well as VM, in tissues, were determined using immunohistochemistry. SOX17, Cyclin D1, and VE-cadherin mRNA in ESCC and their corresponding adjacent normal tissues were quantified using quantitative reverse transcription polymerase chain reaction analysis. Cell invasion, migration, and proliferation were determined after the silencing of VE-cadherin. SOX17, Cyclin D1, and VE-cadherin protein were quantified using Western blotting.

Results

The expression levels of SOX17, Cyclin D1, and VE-cadherin significantly correlated with the clinical characteristics of ESCC. After the VE-cadherin silencing, cell invasion, migration, and proliferation decreased, along with the Cyclin D1 levels, while the SOX17 levels increased.

Conclusion

SOX17, Cyclin D1, and VE-cadherin are involved in the development of ESCC.

HuR Affects the Radiosensitivity of Esophageal Cancer by Regulating the EMT-Related Protein Snail

Purpose

We previously found that Hu antigen R (HuR) can regulate the proliferation and metastasis of esophageal cancer cells. This study aims to explore the effects of HuR on the radiosensitivity of esophageal cancer.

Materials and Method

Analyses of CCK-8, colony formation assay, Western blot, immunofluorescence, flow cytometry, reactive oxygen species (ROS), and mitochondrial membrane potential were conducted to characterize the esophageal cancer cells. Nude mouse models were used to detect the effects of HuR in a combination of X-ray treatment on the subcutaneous xenografts of esophageal cancer. In addition, a luciferase assay was used to detect the direct interaction of HuR with Snail mRNA 3’-UTR.

Results

The down-regulation of HuR combined with X-ray can significantly inhibit the proliferation and colony formation of esophageal cancer cells. Flow cytometry data showed that the down-regulation of HuR could induce a G1 phase cell cycle block in esophageal cancer cells, and aggravate X-ray-induced apoptosis, indicated by the increases of apoptosis-related proteins Bax, caspase-3 and caspase-9. Moreover, the down-regulation of HuR could significantly impair the mitochondrial membrane potential and increase the ROS production and DNA double-strand break marker γH2AX expression in esophageal cancer cells that were exposed to X-rays. In vivo data showed that the down-regulation of HuR combined with radiation significantly decreased the growth of subcutaneous xenograft tumors. Furthermore, HuR could interact with Snail. Up-regulation of Snail can reverse the EMT inhibitory effects caused by HuR down-regulation, and attenuate the tumor-inhibiting and radiosensitizing effects caused by HuR down-regulation.

Conclusion

In summary, our data demonstrate that HuR effectively regulates the radiosensitivity of esophageal cancer, which may be achieved by stabilizing Snail. Thus, HuR/Snail axis is a potentially therapeutic target for the treatment of esophageal cancer.

SOX17-mediated MALAT1-miR-199a-HIF1α axis confers sensitivity in esophageal squamous cell carcinoma cells to radiotherapy

Radiotherapy is a main modality of esophageal squamous cell carcinoma (ESCC) treatment, while radioresistance largely limits the effect of this therapy. Evidence exists reporting that SOX17 may sensitize ESCC cells to irradiation, but the downstream mechanism remains poorly understood. Therefore, we attempt to explore the molecular basis of SOX17 effect on radioresistance in ESCC. The SOX17 expression was measured in ESCC tissues and cells, followed by evaluation of its relationship with patient survival. The fractionated irradiation-induced irradiation-resistant cell line KYSE150R was subjected to gain- and loss-of function studies to explore the effect of SOX17 and downstream effectors MALAT1, miR-199a, and HIF1α on the malignant phenotypes of ESCC. The interaction among these factors was explained using ChIP, dual luciferase reporter, RNA pull-down and RIP assays. Further, the in vivo effect of SOX17 on ESCC irradiation tolerance was assessed in nude mice. SOX17 was underexpressed in ESCC tissues and cells, which was negatively correlated with the prognosis of patients with ESCC. Besides, SOX17 inhibited irradiation tolerance of ESCC cells by suppressing MALAT1 transcription. Notably, MALAT1 acted as miR-199a sponge and thereby enhanced HIF1α expression. Moreover, SOX17 reduced the irradiation tolerance of ESCC cells by reducing HIF1α expression via the MALAT1-miR-199a axis, and attenuated tumor formation in nude mice. Our results indicate that SOX17 can impede the radioresistance of ESCC cells through the MALAT1-miR-199a-HIF1α axis, in support of further research for ESCC radiotherapy.

Role of sirtuins in esophageal cancer: Current status and future prospects

Esophageal cancer (EC) is a malignant cancer that still has a poor prognosis, although its prognosis has been improving with the development of multidisciplinary treatment modalities such as surgery, chemotherapy and radiotherapy. Therefore, identifying specific molecular markers that can be served as biomarkers for the prognosis and treatment response of EC is highly desirable to aid in the personalization and improvement of the precision of medical treatment. Sirtuins are a family of nicotinamide adenine dinucleotide (NAD+)-dependent proteins consisting of seven members (SIRT1-7). These proteins have been reported to be involved in the regulation of a variety of biological functions including apoptosis, metabolism, stress response, senescence, differentiation and cell cycle progression. Given the variety of functions of sirtuins, they are speculated to be associated in some manner with cancer progression. However, while the role of sirtuins in cancer progression has been investigated over the past few years, their precise role remains difficult to characterize, as they have both cancer-promoting and cancer-suppressing properties, depending on the type of cancer. These conflicting characteristics make research into the nature of sirtuins all the more fascinating. However, the role of sirtuins in EC remains unclear due to the limited number of reports concerning sirtuins in EC. We herein review the current findings and future prospects of sirtuins in EC.

Concurrent Chemoradiotherapy-Driven Cell Plasticity by miR-200 Family Implicates the Therapeutic Response of Esophageal Squamous Cell Carcinoma

Esophageal squamous cell carcinoma (ESCC) is a common and fatal malignancy with an increasing incidence worldwide. Over the past decade, concurrent chemoradiotherapy (CCRT) with or without surgery is an emerging therapeutic approach for locally advanced ESCC. Unfortunately, many patients exhibit poor response or develop acquired resistance to CCRT. Once resistance occurs, the overall survival rate drops down rapidly and without proper further treatment options, poses a critical clinical challenge for ESCC therapy. Here, we utilized lab-created CCRT-resistant cells as a preclinical study model to investigate the association of chemoradioresistantresistance with miRNA-mediated cell plasticity alteration, and to determine whether reversing EMT status can re-sensitize refractory cancer cells to CCRT response. During the CCRT treatment course, refractory cancer cells adopted the conversion of epithelial to mesenchymal phenotype; additionally, miR-200 family members were found significantly down-regulated in CCRT resistance cells by miRNA microarray screening. Down-regulated miR-200 family in CCRT resistance cells suppressed E-cadherin expression through snail and slug, and accompany with an increase in N-cadherin. Rescuing expressions of miR-200 family members in CCRT resistance cells, particularly in miR-200b and miR-200c, could convert cells to epithelial phenotype by increasing E-cadherin expression and sensitize cells to CCRT treatment. Conversely, the suppression of miR-200b and miR-200c in ESCC cells attenuated E-cadherin, and that converted cells to mesenchymal type by elevating N-cadherin expression, and impaired cell sensitivity to CCRT treatment. Moreover, the results of ESCC specimens staining established the clinical relevance that higher N-cadherin expression levels associate with the poor CCRT response outcome in ESCC patients. Conclusively, miR-200b and miR-200c can modulate the conversion of epithelial-mesenchymal phenotype in ESCC, and thereby altering the response of cells to CCRT treatment. Targeting epithelial-mesenchymal conversion in acquired CCRT resistance may be a potential therapeutic option for ESCC patients.

FOXQ1-mediated SIRT1 upregulation enhances stemness and radio-resistance of colorectal cancer cells and restores intestinal microbiota function by promoting β-catenin nuclear translocation

Background

Resistance of colorectal cancer (CRC) cells to radiotherapy considerably contributes to poor clinical outcomes of CRC patients. Microarray profiling in this study revealed the differentially expressed forkhead box Q1 (FOXQ1) in CRC, and thus we aimed to illustrate the role of FOXQ1 in CRC by modulating stemness and radio-resistance of CRC cells.

Methods

CRC and adjacent normal tissues were collected from CRC patients, and the correlation between FOXQ1 expression and CRC prognosis was analyzed. Subsequently, we determined the expression of FOXQ1, sirtuin 1 (SIRT1) and β-catenin in CRC tissues and cell lines. The binding affinity between FOXQ1 and SIRT1 and that between SIRT1 and β-catenin were validated with luciferase reporter gene, Co-IP and ChIP assays. Following a metagenomics analysis of CRC intestinal microbiota, the effects of the FOXQ1/SIRT1/β-catenin axis on CRC stem cell phenotypes and radio-resistance was evaluated in vitro and in vivo through manipulation of gene expression. Besides, mouse feces were collected to examine changes in intestinal microbiota.

Results

FOXQ1 was highly expressed in CRC tissues and cells and positively correlated with poor prognosis of CRC patients. FOXQ1 overexpression contributed to resistance of CRC cells to radiation. Knockdown of FOXQ1 inhibited the stemness of CRC cells and reversed their radio-resistance. FOXQ1 enhanced the transcriptional expression of SIRT1, and SIRT1 enhanced the expression and nuclear translocation of β-catenin. Knockdown of FOXQ1 repressed SIRT1 expression, thus reducing the stemness and radio-resistance of CRC cells. Moreover, FOXQ1 knockdown suppressed CRC xenograft formation in xenograft-bearing nude mice through inhibiting SIRT1 and β-catenin to reduce the content of pathological bacteria that were up-regulated in CRC.

Conclusion

FOXQ1-mediated SIRT1 upregulation augments expression and nuclear translocation of β-catenin and benefits CRC-related intestinal pathological bacterial, thereby enhancing the stemness and radio-resistance of CRC cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02239-4.

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.

MicroRNAs regulating SOX2 in cancer progression and therapy response

The proliferation, metastasis and therapy response of tumour cells are tightly regulated by interaction among various signalling networks. The microRNAs (miRNAs) can bind to 3'-UTR of mRNA and down-regulate expression of target gene. The miRNAs target various molecular pathways in regulating biological events such as apoptosis, differentiation, angiogenesis and migration. The aberrant expression of miRNAs occurs in cancers and they have both tumour-suppressor and tumour-promoting functions. On the contrary, SOX proteins are capable of binding to DNA and regulating gene expression. SOX2 is a well-known member of SOX family that its overexpression in different cancers to ensure progression and stemness. The present review focuses on modulatory impact of miRNAs on SOX2 in affecting growth, migration and therapy response of cancers. The lncRNAs and circRNAs can function as upstream mediators of miRNA/SOX2 axis in cancers. In addition, NF-κB, TNF-α and SOX17 are among other molecular pathways regulating miRNA/SOX2 axis in cancer. Noteworthy, anti-cancer compounds including bufalin and ovatodiolide are suggested to regulate miRNA/SOX2 axis in cancers. The translation of current findings to clinical course can pave the way to effective treatment of cancer patients and improve their prognosis.

A methyltransferase-like 14/miR-99a-5p/tribble 2 positive feedback circuit promotes cancer stem cell persistence and radioresistance via histone deacetylase 2-mediated epigenetic modulation in esophageal squamous cell carcinoma

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is a highly aggressive and treatment-resistant tumor. The biological implications and molecular mechanism of cancer stem-like cells (CSCs) in ESCC, which contribute to therapeutic resistance such as radioresistance, remain elusive.

METHODS

Quantitative real-time polymerase chain reaction, western blotting, immunohistochemistry, and in situ hybridization assays were used to detect methyltransferase-like 14 miR-99a-5p tribble 2 (METTL14/miR-99a-5p/TRIB2) expression in ESCC. The biological functions of METTL14/miR-99a-5p/TRIB2 were demonstrated in vitro and in vivo. Mass spectrum analysis was used to identify the downstream proteins regulated by TRIB2. Chromatin immunoprecipitation (IP), IP, N6 -methyladenosine (m6 A)-RNA IP, luciferase reporter, and ubiquitination assays were employed to explore the molecular mechanisms underlying this feedback circuit and its downstream pathways.

RESULTS

We found that miR-99a-5p was significantly decreased in ESCC. miR-99a-5p inhibited CSCs persistence and the radioresistance of ESCC cells, and miR-99a-5p downregulation predicted an unfavorable prognosis of ESCC patients. Mechanically, we unveiled a METTL14-miR-99a-5p-TRIB2 positive feedback loop that enhances CSC properties and radioresistance of ESCC cells. METTL14, an m6 A RNA methyltransferase downregulated in ESCC, suppresses TRIB2 expression via miR-99a-5p-mediated degradation of TRIB2 mRNA by targeting its 3' untranslated region, whereas TRIB2 induces ubiquitin-mediated proteasomal degradation of METTL14 in a COP1-dependent manner. METTL14 upregulates miR-99a-5p by modulating m6 A-mediated, DiGeorge critical region 8-dependent pri-mir-99a processing. Hyperactivation of TRIB2 resulting from this positive circuit was closely correlated with radioresistance and CSC characteristics. Furthermore, TRIB2 activates HDAC2 and subsequently induces p21 epigenetic repression through Akt/mTOR/S6K1 signaling pathway activation. Pharmacologic inhibition of HDAC2 effectively attenuates the TRIB2-mediated effect both in vitro and in patient-derived xenograft models.

CONCLUSION

Our data highlight the presence of the METTL14/miR-99a-5p/TRIB2 axis and show that it is positively associated with CSC characteristics and radioresistance of ESCC, suggesting potential therapeutic targets for ESCC treatment.

Prognostic and clinicopathological significance of TMEFF2, SMOC-2, and SOX17 expression in endometrial carcinoma

Background there is a need for novel biomarkers and targeting therapies for predicting Endometrial carcinoma (EC) progression and recurrence. TMEFF2 is a gene that was found to play a role in EMT. SMOC-2 is expressed in embryogenesis and it was identified as a recent stem cell-related gene that has a role in cancer progression. SRY-box 17 (SOX17) is a member of the SRY-related HMG-box (SOX) family of transcription factors. Dysregulation or downregulation of SOX17 expression was found in many cancer tissues.

AIM

In the present study, we aimed to assess the tissue protein expressions of TMEFF2, SMOC-2, and SOX17 in EC using immunohistochemistry to evaluate their clinicopathological values and prognostic roles in EC patients.

PATIENTS AND METHODS

This is prospective cohort study included 120 patients with EC. Sections from 120 paraffin blocks were retrieved and stained with TMEFF2, SMOC-2, and SOX17 using immunohistochemistry, the expression of markers in all tissue samples was assessed, analyzed and correlation of pathological parameters with the levels of expression was done. All patients were followed up till death or till the last known alive data for about 50 months (range from 25 to 60).

RESULTS

TMEFF2, SMOC-2 expression was correlated with the presence of lymph node metastases (p = 0.023), distant metastasis (p = 0.039) recurrence of the tumor after successful therapy, overall survival, and disease-free survival (p < 0.001). SOX17 positive expression was positively correlated with low grade (p = 0.019), absence of lymph node metastasis (p = 0.001), absence of distant metastasis (p = 0.013), low stage (p = 0.03), and its negative expression was positively correlated with recurrence of the tumor after successful therapy, overall survival and disease-free survival (p = 0.001). In conclusion, we demonstrated that both TMEFF2 and SMOC-2 were highly expressed in EC and were associated with a shortened survival rate, dismal outcome, and poor prognosis in EC patients. While SOX17 expression was related to a favorable outcome and its down-regulation was associated with dismal EC patient's survival.

SOX17 inhibits proliferation and invasion of neuroblastoma through CXCL12/CXCR4 signaling axis

SOX17 has been shown to be involved in the transcriptional regulation of CXCR4, and CXCL12 functions by binding to its receptor CXCR4. Here, we explored the expression of SOX17 in neuroblastoma (NB), its mutual regulation with CXCL12, and its effects on cancer cell proliferation, migration and invasion. Five human NB cell lines and 15 pairs of NB and adjacent tissue specimens were used, to conduct RT-qPCR, immunohistochemistry, western blot, ELISA, CCK-8, colony formation, Edu, transwell, chromatin immunoprecipitation (ChIP), and dual-luciferase assays, to study the role of SOX17 in NB. SOX17 levels were reduced in both NB tissues and cell lines. SOX17 inhibited NB tumor growth, migration and invasion in vivo and suppressed NB cell proliferation, migration, and invasion in vitro. SOX17 knockdown or overexpression revealed a negative correlation between SOX17 and CXCL12/CXCR4 pathway activation. ChIP and dual-luciferase assays in NB cells demonstrated that SOX17 significantly inhibited CXCL12 gene and protein levels by binding to CXCL12 promoter regions. In vivo and in vitro experiments using the CXCR4 antagonist, AMD3100, demonstrated that cell proliferation, migration and invasion were significantly abrogated by AMD3100 in NB cells with SOX17 knocked down. Further, AMD3100 impaired growth of NB tumors with SOX17 knocked down in mice. Importantly, SOX17 bound to the CXCL12 promoter, which then activated downstream targets to regulate cell viability, proliferation, and migration. In conclusion, our data demonstrate that SOX17 expression is repressed in NB tissues and cells, and that SOX17 suppresses NB tumor formation and proliferation through inhibition of CXCL12/CXCR4 signaling.

ERCC1 rs11615 polymorphism and chemosensitivity to platinum drugs in patients with ovarian cancer: a systematic review and meta-analysis

OBJECTIVE

To explore the relationship between ERCC1 rs11615 polymorphism and chemosensitivity to platinum drugs in ovarian cancer by the method of meta-analysis.

METHODS

Pubmed, Web of Science, EMBASE, Cochrane Library, China National Knowledge Infrastructure (CNKI), and China Wanfang databases were comprehensively searched up to September 2020, to identify the relationship between ERCC1 rs11615 polymorphism and chemosensitivity of ovarian cancer. The data was analyzed by Stata 15.0 statistic software.

RESULTS

A total of 10 published papers were included, including 1866 patients with ovarian cancer. The results showed that compared allele C at ERCC1 rs11615 locus with allele T, the pooled OR was 0.92 (95%CI:0.68 ~ 1.24, P > 0.05). There were no significant differences in recessive, dominant, homozygous, and heterozygous models. In accordance with a subgroup analysis of Ethnicity, all genotypes were statistically significant in the Asian population. In the allelic, dominant, recessive, homozygous and heterozygous models, the OR was 0.70 (95%CI:0.51 ~ 0.95), 0.20 (95%CI:0.07 ~ 0.56), 0.79 (95%CI:0.63 ~ 1.00), 0.21 (95%CI:0.07 ~ 0.59), 0.19 (95%CI:0.07 ~ 0.54), respectively, while in the Caucasian population, no statistically significant genotype was found.

CONCLUSION

The ERCC1 rs11615 polymorphism is associated with chemosensitivity in patients with ovarian cancer, especially in the Asian population, but not in the Caucasian population.

SOX-17 is involved in invasion and apoptosis of colorectal cancer cells through regulating miR-302b-3p expression

The prognosis of advanced colorectal cancer (CRC) is currently still very poor, which suggests that the biological mechanisms of CRC oncogenesis are not fully understood. This study was conducted to explore the regulatory effect of SOX-17 on the expression of microRNA (miR)-302b-3p, and the involvement of SOX-17 in the invasion and apoptosis of CRC cells. The expression of SOX-17 and miR-302a,b,c,d-3p in colorectal cancer and normal colon epithelial cell lines was measured by real-time polymerase chain reaction and/or western blot. The regulatory effects of SOX-17 on miR-302b-3p gene in HT29 and LoVo cells were tested using the ChiP assay. The biological activities of SOX-17 and miR-302b-3p were evaluated by invasion and apoptosis assay. Results showed that transfection of SOX-17 small interfering RNA (siSOX-17) significantly increased, whereas transfection of SOX-17 overexpression vector (oeSOX-17) significantly decreased, miR-302b expression in HT29 and LoVo cells. Cotransfection of oeSOX-17 and miR-302b-3p inhibitor (INmiR-302b) significantly blocked the effects of SOX-17 in HT29 and LoVo cells. ChIP experiments showed that SOX-17 bonded to the miR-302b-3p promoter in HT29 and LoVo cells. Transfection of oeSOX-17 and miR-302b-3p mimics (MImiR-302b) significantly decreased, whereas transfection of siSOX-17 and INmiR-302b significantly increased, the invasion of HT29 and LoVo cells. In contrast, transfection of oeSOX-17 and MImiR-302b significantly increased, while transfection of siSOX-17 and INmiR-302b significantly decreased, apoptosis in HT29 and LoVo cells. Cotransfection of oeSOX-17 and INmiR-302b significantly blocked the effects of oeSOX-17 on cell invasion and apoptosis in HT29 and LoVo cells. These results suggested that SOX-17 can bind to the promoter of miR-302b-3p gene to regulate its expression, while both SOX-17 and miR-302b regulate the invasion and apoptosis in colorectal cancer cells.

Identification of DNA-Repair-Related Five-Gene Signature to Predict Prognosis in Patients with Esophageal Cancer

Esophageal cancer (ESCA) is a leading cause of cancer-related mortality, with poor prognosis worldwide. DNA damage repair is one of the hallmarks of cancer. Loss of genomic integrity owing to inactivation of DNA repair genes can increase the risk of cancer progression and lead to poor prognosis. We aimed to identify a novel gene signature related to DNA repair to predict the prognosis of ESCA patients. Based on gene expression profiles of ESCA patients from The Cancer Genome Atlas and gene set enrichment analysis, 102 genes related to DNA repair were identified as candidates. After stepwise Cox regression analysis, we established a five-gene prognostic model comprising DGCR8, POM121, TAF9, UPF3B, and BCAP31. Kaplan-Meier survival analysis confirmed a strong correlation between the prognostic model and survival. Moreover, we verified the clinical value of the prognostic signature under the influence of different clinical parameters. We found that small-molecule drugs (trametinib, selumetinib, and refametinib) could help to improve patient survival. In summary, our study provides a novel and promising prognostic signature based on DNA-repair-related genes to predict survival of patients with ESCA. Systematic data mining provides a theoretical basis for further exploring the molecular pathogenesis of ESCA and identifying therapeutic targets.

The mechanisms and reversal strategies of tumor radioresistance in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of most lethal malignancies with high aggressive potential in the world. Radiotherapy is used as one curative treatment modality for ESCC patients. Due to radioresistance, the 5-year survival rates of patients after radiotherapy is less than 20%. Tumor radioresistance is very complex and heterogeneous. Cancer-associated fibroblasts (CAFs), as one major component of tumor microenvironment (TME), play critical roles in regulating tumor radioresponse through multiple mechanisms and are increasingly considered as important anti-cancer targets. Cancer stemness, which renders cancer cells to be extremely resistant to conventional therapies, is involved in ESCC radioresistance due to the activation of Wnt/β-catenin, Notch, Hedgehog and Hippo (HH) pathways, or the induction of epithelial-mesenchymal transition (EMT), hypoxia and autophagy. Non-protein-coding RNAs (ncRNAs), which account for more than 90% of the genome, are involved in esophageal cancer initiation and progression through regulating the activation or inactivation of downstream signaling pathways and the expressions of target genes. Herein, we mainly reviewed the role of CAFs, cancer stemness, non-coding RNAs as well as others in the development of radioresistance and clarify the involved mechanisms. Furthermore, we summarized the potential strategies which were reported to reverse radioresistance in ESCC. Together, this review gives a systematic coverage of radioresistance mechanisms and reversal strategies and contributes to better understanding of tumor radioresistance for the exploitation of novel intervention strategies in ESCC.

Syntaphilin downregulation facilitates radioresistance via mediating mitochondria distribution in esophageal squamous cell carcinoma

Syntaphilin (SNPH) halts mitochondrial movements and regulates proliferation-motility phenotype switching of cancer cells. We sought to investigate the significance of SNPH-mediated mitochondria distribution in radioresistant (RR) phenotype switching in esophageal squamous cell carcinoma (ESCC). RR ESCC cells were established by long-term exposure to radiation. Effects of SNPH on proliferation, migration, mitochondrial distribution, radiation-induced oxidative damage and radiosensitivity were investigated by overexpressing or silencing SNPH. The mechanisms regulating SNPH expression and the potential molecules mediating the SNPH-re-expression-induced radiosensitization were explored. SNPH expression in specimens from 156 patients was analyzed to evaluate its clinical significance. We found that RR ESCC cells had a sparse mitochondrial network and lower SNPH level. SNPH reconstitution in RR ESCC cells inhibited migration, induced proliferation and mitochondrial aggregation, exacerbated the radiation-induced oxidative damage and ultimately promoted radiosensitization. Mechanistically, ubiquitin-proteasomal degradation and histone modification contributed to SNPH downregulation in RR ESCC cells. Subsequently, we found that CREB dephosphorylation facilitated the SNPH re-expression-induced radiosensitization. Furthermore, SNPH expression was correlated with the radiotherapeutic efficacy and served as an independent prognostic factor for survival of ESCC patients. Our study revealed that low SNPH expression was a novel indicator for radioresistance, and targeting SNPH could be a promising regimen to improve the radiotherapeutic efficiency in ESCC patients.

The role of SOX family transcription factors in gastric cancer

Gastric cancer (GC) is a leading cause of death worldwide. GC is the third-most common cause of cancer-related death after lung and colorectal cancer. It is also the fifth-most commonly diagnosed cancer. Accumulating evidence has revealed the role of signaling networks in GC progression. Identification of these molecular pathways can provide new insight into therapeutic approaches for GC. Several molecular factors involved in GC can play both onco-suppressor and oncogene roles. Sex-determining region Y (Sry)-box-containing (SOX) family members are transcription factors with a well-known role in cancer. SOX proteins can bind to DNA to regulate cellular pathways via a highly conserved domain known as high mobility group (HMG). In the present review, the roles of SOX proteins in the progression and/or inhibition of GC are discussed. The dual role of SOX proteins as tumor-promoting and tumor-suppressing factors is highlighted. SOX members can affect upstream mediators (microRNAs, long non-coding RNAs and NF-κB) and down-stream mediators (FAK, HIF-1α, CDX2 and PTEN) in GC. The possible role of anti-tumor compounds to target SOX pathway members in GC therapy is described. Moreover, SOX proteins may be used as diagnostic or prognostic biomarkers in GC.

Multiple functions of p21 in cancer radiotherapy

BACKGROUND

Greater than half of cancer patients experience radiation therapy, for both radical and palliative objectives. It is well known that researches on radiation response mechanisms are conducive to improve the efficacy of cancer radiotherapy. p21 was initially identified as a widespread inhibitor of cyclin-dependent kinases, transcriptionally modulated by p53 and a marker of cellular senescence. It was once considered that p21 acts as a tumour suppressor mainly to restrain cell cycle progression, thereby resulting in growth suppression. With the deepening researches on p21, p21 has been found to regulate radiation responses via participating in multiple cellular processes, including cell cycle arrest, apoptosis, DNA repair, senescence and autophagy. Hence, a comprehensive summary of the p21's functions in radiation response will provide a new perspective for radiotherapy against cancer.

METHODS

We summarize the recent pertinent literature from various electronic databases, including PubMed and analyzed several datasets from Gene Expression Omnibus database. This review discusses how p21 influences the effect of cancer radiotherapy via involving in multiple signaling pathways and expounds the feasibility, barrier and risks of using p21 as a biomarker as well as a therapeutic target of radiotherapy.

CONCLUSION

p21's complicated and important functions in cancer radiotherapy make it a promising therapeutic target. Besides, more thorough insights of p21 are needed to make it a safe therapeutic target.

Sry-related High Mobility Group Box 17 Functions as a Tumor Suppressor by Antagonizing the Wingless-related Integration Site Pathway

A transcription factor Sry-related high mobility group box (Sox) 17 is involved in developmental processes including spermatogenesis, cardiovascular system, endoderm formation, and so on. In this article, we firstly review the studies on the relation between the Sox17 expression and tumor malignancy. Although Sox17 positively promotes various tissue development, most of the cancers associated with Sox17 show decreased expression levels of Sox17, and an inverse correlation between Sox17 expression and malignancy is revealed. We briefly discuss the mechanism of such Sox17 down-regulation by focusing on DNA methylation of CpG sites located in the Sox17 gene promoter. Next, we overview the function of Sox17 in the fetal hematopoiesis, particularly in the dorsal aorta in midgestation mouse embryos. The Sox17 expression in hematopoietic stem cell (HSC)-containing intra-aortic hematopoietic cell cluster (IAHCs) is important for the cluster formation with the hematopoietic ability. The sustained expression of Sox17 in adult bone marrow HSCs and the cells in IAHCs of the dorsal aorta indicate abnormalities that are low lymphocyte chimerism and the aberrant proliferation of common myeloid progenitors in transplantation experiments. We then summarize the perspectives of Sox17 research in cancer control.

Upregulation of deubiquitinase USP7 by transcription factor FOXO6 promotes EC progression via targeting the JMJD3/CLU axis

Esophageal carcinoma (EC) is recognized as one of the most frequently occurring malignancies worldwide, and its high morbidity rate motivates efforts to identify potential therapeutic targets. Notably, forkhead box (FOX) family genes are highlighted as possible biomarkers for diagnostics, prognostics, and therapeutics of various malignancies, including EC. Our present study was performed to investigate the underlying mechanism of FOXO6 on the development of EC. We observed a significant upregulation of FOXO6 in EC tissues, contributing to the migration and proliferation in EC cells through gain- and loss-of-function assays. FOXO6 directly interacted with the ubiquitin-specific processing protease 7 (USP7) gene promoter and enhanced its transcriptional activity, which resulted in suppressed cancer cell apoptosis as revealed by chromatin immunoprecipitation (ChIP)-qPCR. USP7 enhanced the ubiquitination of Jumonji domain-containing protein D3 (JMJD3), elevated JMJD3-promoted growth of EC cells, and transcriptionally activated clusterin (CLU) expression at the promoter region via histone H3 lysine 27 tri-methyl (H3K27me3) demethylation, according to immunoprecipitation and ubiquitination assays. Finally, we verified that FOXO6 mediated effects on the USP7/JMJD3/CLU axis to exert an oncogenic role in vivo, which was blocked by USP7 and JMJD3 inhibitor. Our findings demonstrate an important role of the FOXO6/USP7/JMJD3/CLU pathway in EC progression and thus provide attractive potential therapeutic targets for EC patients.

A DNA methylation-based test for esophageal cancer detection

Background

Esophageal cancer (ECa) is the 7th most incident cancer and the 6th leading cause of cancer-related death. Most patients are diagnosed with locally advanced or metastatic disease, enduring poor survival. Biomarkers enabling early cancer detection may improve patient management, treatment effectiveness, and survival, are urgently needed. In this context, epigenetic-based biomarkers such as DNA methylation are potential candidates.

Methods

Herein, we sought to identify and validate DNA methylation-based biomarkers for early detection and prediction of response to therapy in ECa patients. Promoter methylation levels were assessed in a series of treatment-naïve ECa, post-neoadjuvant treatment ECa, and normal esophagus tissues, using quantitative methylation-specific PCR for COL14A1, GPX3, and ZNF569.

Results

ZNF569 methylation (ZNF569me) levels significantly differed between ECa and normal samples (p < 0.001). Moreover, COL14A1 methylation (COL14A1me) and GPX3 methylation (GPX3me) levels discriminated adenocarcinomas and squamous cell carcinomas, respectively, from normal samples (p = 0.002 and p = 0.009, respectively). COL14A1me & ZNF569me accurately identified adenocarcinomas (82.29%) whereas GPX3me & ZNF569me identified squamous cell carcinomas with 81.73% accuracy. Furthermore, ZNF569me and GPX3me levels significantly differed between normal and pre-treated ECa.

Conclusion

The biomarker potential of a specific panel of methylated genes for ECa was confirmed. These might prove useful for early detection and might allow for the identification of minimal residual disease after adjuvant therapy.