| ObjectiveThe majority of hypopharyngeal carcinoma is squamous cell carcinoma,which is a kind of head and neck tumor with low survival rate.Hypopharyngeal squamous cell carcinoma occurs at a concealed site with atypical symptoms and is often seen in the middle to late stage.The results showed that there was no statistically significant difference in the survival rate between non-surgical treatment and surgical resection,and the conservative treatment with organ function preservation significantly improved the quality of life.Therefore,it is of great significance for the diagnosis and treatment of hypopharyngeal squamous cell carcinoma to deeply explore the biological mechanism of its occurrence and development.The degree of differentiation of tumor cells is an important factor in determining the malignancy of tumor.Unfortunately,we can't get the earliest differentiation in the early stages compared to the final differentiation.The clear physical structure of the undifferentiated and differentiated layers,the clear marker proteins of each layer and the convenience of in vivo and in vitro differentiation experiments make the laminated squamous epidermis an ideal tissue for the study of epithelial cell differentiation.We speculate that the differentiation of hypopharyngeal squamous cell carcinoma may share some common mechanisms with the differentiation of epidermal cells.It has been reported that the modification of histone H3K4me3 and its demethylated enzyme Jarid1 b play an important role in the development and proliferation and differentiation of tumor cells,but the mechanism of action in epidermis and hypopharyngeal squamous cell carcinoma is still unclear.This study aims to clarify the regulatory mechanism of H3K4me3 and its demethylating enzyme Jarid1 b in the epidermis,and further study its effect on the proliferation and differentiation of hypopharyngeal squamous cell carcinoma by reference to this mechanism.Research methods1.Human foreskin tissue sections were selected for immunohistochemistry to detect the differential expression of H3K4me3 and Jarid1 b in basal cells and differentiated layer cells of epidermal cells.The expression of H3K4me3,Jarid1 b and differentiation marker proteins was detected in HaCaT cells induced by high calcium.2.Gene knockout or overexpression of Jarid1 b in HaCaT cells,and the role of Jarid1 b in cell proliferation and differentiation was determined by CCK8,Western blotting,RTqPCR and other methods.3.Hybrid Jarid1 b gene knockdown HaCaT cells and mouse fibroblasts were transplanted into the back of nude mice to construct recombinant epidermis,and the effect of Jarid1 b on the differentiation of recombinant epidermis was observed by immunohistochemistry.4.In HaCaT and FaDu cells,Western blotting,RT-qPCR and other methods were used to detect the effect of Jarid1 b on the AKT pathway and stromal epithelial transformation gene.5.GraphPad was used for data analysis,and P < 0.05 was considered to be statistically significant.Results1.Studies on epidermis and HaCaT cells showed that during epidermal cell differentiation,H3K4me3 decreased and Jarid1 b expression increased.Jarid1 b promoted HaCaT cell differentiation and inhibited proliferation.In terms of mechanism,we found that Jarid1 b significantly increased the expression of mesenchymal-epithelial transformation related genes in HaCaT,among which Ovol1 positively regulated the expression of differentiation genes K10 and IVL.In addition,PI3K/AKT pathway inhibitor inhibits Ovol1 expression.The overexpression of the inhibitor Ship1 in the PI3K/AKT pathway inhibited the expression of Ovol1.Ship1 knockdown activates the PI3K/AKT pathway and enhances Ovol1 expression.2.The study on hypopharyngeal squamous cell carcinoma showed that Ovol1 expression increased in the moderately differentiated hypopharyngeal squamous cell carcinoma,compared with the poorly differentiated hypopharyngeal squamous cell carcinoma.Overexpression of Ovol1 in FaDu cells increased the expression of epithelial differentiation marker protein K10 and inhibited cell proliferation.Jarid1 b positively regulates Ovol1 expression through the PI3K/AKT signaling pathway.ConclusionIn summary,our study suggests that Jarid1 b may promote differentiation of epidermal HaCaT and FaDu cells in hypopharyngeal squamous cell carcinoma by inhibiting Ship1 activation of AKT/Ovol1 pathway,and Jarid1 b plays an anticancer gene role in hypopharyngeal squamous cell carcinoma.Research significanceThe proliferation and differentiation of epidermal squamous cells are the two most fundamental factors that determine the normal development of skin.Squamous cell carcinoma,on the other hand,is derived from squamous cells,which we speculate have similar regulatory mechanisms to skin development.Epidermal stem cell differentiation was used as a model to screen the regulatory molecules of cell proliferation and differentiation.Through this innovative model of basic to clinical research on squamous cell carcinoma,and through in-depth study on the important regulatory molecules of epidermal stem cell proliferation and differentiation,it will provide the most powerful clues for us to crack the mechanism of squamous cell carcinoma.On this basis,the gene phenotypes of important molecules in the regulatory network were verified in squamous cell carcinoma to search for potential molecular targets.This study elucidated that Jarid1 b promoted epidermal stem cell differentiation,which was consistent with the tumor suppressor function and mechanism in hypopharyngeal cancer.Jarid1 b activates AKT/Ovol1 to promote differentiation and inhibit proliferation of epithelial and hypopharyngeal squamous carcinoma cells by down-regulating Ship1,an AKT pathway that inhibits molecular expression.Before that,Jarid1 b was generally considered to be an oncogene.Combined with our research results in hypopharyngeal cancer,people have re-recognized the function of Jarid1 b,which is undoubtedly a great innovation in this field and has positive innovative significance for the study of skin diseases and hypopharyngeal squamous cell carcinoma. |
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