| Esophageal cancer is one of the most lethal malignancies worldwide.The incidence of esophageal cancer has dramatically increased over the past few decades.Despite there are huge process in treatment for esophageal cancers,thr outcomes of 5-year survival and 5-year post-esophagectomy survival for esophageal cancer are still remain poor.In current,esophageal cancer is usually diagnosed at its advanced stage,mainly due to the lack of early clinical symptoms.In order to improve the prognosis of patients after surgery,these patients are usually treated with adjuvant concurrent chemoradiotherapy(CCRT)to reduce tumor size.However,patients who do not respond well to CCRT,may increase the level of toxicity and may result in delaying surgery,which will increase the death rate of esophageal cancer.Esophageal squamous cell carcinoma(ESCC)is a high-incidence subtype of esophageal cancer in China.ESCC is the main cause of death from esophageal cancer,with an incidence rate exceeding 125/100,000/year.China’s large population and high incidence rate result in China having about half of all ESCC case’s on the planet.These regions are also high rates of cardiac adenocarcinoma and ESCC.In some regions,These two cancers account for half of all cancer deaths.MicroRNAs(miRNAs)are a class of small noncoding RNAs that can regulate protein coding and gene transcription which are associated with nearly all known physiological and pathological processes,especially cancer.miRNAs can influence cancer pathogenesis and play key roles in oncogenes or tumor suppressors.miRNAs also play an important role in the development and metastasis of esophageal cancer,so they are often used to detect the occurrence of esophageal cancer.In esophageal cancer,miRNA dysregulation plays a critical role in cancer prognosis and patient response to adjuvant therapy.In this paper,we studied the related effects of miRNAs on carcinogenesis,tumor suppression and drug resistance and their roles in the pathogenesis and treatment of esophageal cancer.In the current study,miR-375 was significantly downregulated in various cancers and inhibited carcinogenesis by targeting several important oncogenes such as AEG-1,YAP1,IGF1R and PDK1.Alterations of miR-375 in cancer are caused by multiple mechanisms,including dysregulation of transcription factors,aberrant promoter methylation,etc.Decreased expression of miR-375 in tissue or circulation may indicate the presence of tumors and the poor prognosis of many malignancies.In addition,miR-375 can inhibit tumor cell growth in vitro and in vivo,and miR-375 represents a direction for developing targeted therapy.Here,we propose a new scientific hypothesis that cell-to-cell delivered miR-375 plays a crucial role in ESCC progression and metastasis.Around this scientific hypothesis,we have drawn the following three conclusions in our later experiments.1.miR-375 reduces ESCC tumor growth by inhibiting the proliferative activity and migration ability of cancer cells.After treating ESCC cells with miR-375 analogs,we performed EdU staining,Transwell assay,tumorsphere formation assay and flow cytometry on ESCC cells and found that miR-375 had a significant inhibitory effect on ESCC cell biological functions.ESCC cell proliferation,invasion,migration and tumorsphere formation were all inhibited.At the same time,we also found that ESCC cells undergo apoptosis.In addition,we also found that apoptosis-related genes(such as Bcl-2,Bcl-xl,and Bax)were up-regulated by RT-qPCR and Western blot analysis,while sternness-related genes(such as CD 133,Nanog,and OCT-4)were up-regulated.down.This result indicated that miR-375 inhibited ESCC cell proliferation,invasion,migration and stemness,while stimulating ESCC cell apoptosis.2.miR-375 affects the occurrence of ESCC by affecting the expression of ENAH geneBy using starBase,TargetScan,DIANA and mirDIP databases to predict the downstream target genes of miR-375,we found 821,301,1251 and 645 candidate regulatory genes of miR-375.Furthermore,by microarray analysis of GSE29001 and GSE20347 datasets in the GEO database,we screened 843 and 432 differentially expressed genes regulated by miR-375.We found ENAH to be the only intersecting gene.Meanwhile,the expression of ENAH in ESCC tissues was higher than that in adjacent normal tissues.Further studies found that depleted ENAH expression inhibited ESCC cellproliferation,invasion,migration,tumorsphere formation,and promoted apoptosis.Meanwhile,the expression of ENAH attenuated the inhibitory effect of miR-375 on ESCC cell proliferation,invasion,migration and tumorsphere formation.Taken together,miR-375 downregulates ENAH to inhibit ESCC cell proliferation and promote apoptosis in angiogenesis,migration,stemness and in vitro.3.miR-375 regulates ESCC development through bone marrow mesenchymal stem cell(HUCMSC)-derived exosomesBy using transmission electron microscopy(TEM),we firstly confirmed that exosomes isolated from hUCMSCs had round or oval membrane vesicles(40-150 nm in diameter)with similar morphology.Meanwhile,miR-375 was determined to be highly expressed in purified hUCMSCs-exo by RT-qPCR.hUCMSCs-exo were co-cultured with ESCC cells.ESCC cells were able to take up miR-375 in exosomes for hUCMSCs-exo utilization.Co-culture of ESCC cells treated with hUCMSCs-exo using miR-375 inhibitor found that hUCMSCs-exo attenuated ESCC cell proliferation,migration,invasion and tumorsphere formation,while enhancing ESCC cell apoptosis.In conclusion,this study aimed to investigate the mechanism of miR-375 exosomes derived from human umbilical cord mesenchymal stem cells(hUCMSCs)in esophageal squamous cell carcinoma(ESCC).By detecting the expression of miR-375 and its targeted activating homolog(ENAH)in esophageal squamous cell carcinoma tissues and cells,the effect of its expression changes on the proliferation,invasion,migration and tumor formation of esophageal squamous cell carcinoma was detected.Transfected hUCMSCs-derived exosomes(hUCMSCs-exo)were isolated and co-cultured with ESCC cells to observe the effect of hUCMSCs exosome-mediated miR-375 on ESCC development.Finally,we investigated the effect of miR-375 on tumor growth in vivo.hUCMSCs-exo can inhibit the expression of.ENAH through miR-375,thereby inhibiting the occurrence and development of ESCC. |
