Expression And Effect Of Nerve Growth Factor And It't Receptor P75 In Human Laryngocarcinoma

Investigation about the carcinogenesis,growth and metastatic of laryngocarcinoma are warm spots in head and neck cancer research.This is also significant for early diagnosis or gene therapy.Nerve growth factor and it' s receptor p75 possess multimodulation role for cells grow.However,up to now, there is no report about the expression and functions of NGF or p75NTR in laryngocarcinoma.We examined normal laryngeal mucosa,para-cancer laryngeal mucosa, laryngeal papilloma tissues and Laryngeal squamous carcinoma for NGF, p75NTR,p63,Ki67 immunohistochemistry staining.Positive expression of NGF,p75NTR,p63,Ki67 was found in normal stratified squamous epithelium. The positive expression ratio and distribution range of NGF were gradually raised accompanied the malignant progression of epithelial tissues.We find higher NGF expressions in severce atypical hyperplasia than lightly atypical hyperplasia and furthermore than normal laryngeal mucosa.So NGF can be used as a marker for malignant progression toward laryngoearcinoma.High level expression of NGF reflected higher proliferation energy of laryngocarcinoma cells.Overexpression of NGF in laryngocarcinoma was significantly related to positive lymph node metastasis.The functions of NGF signal may participate in the process of development and metastasis in laryngocarcinoma.Positive expression of p75NTR was only located in basal cell layer of normal laryngeal mucosa.The p75NTR positive staining distributed in epithelium basal layer,and this distribution was more exclusive than p63 or Ki67. So p75NTR can be used as a potential marker for stem cells of human normal laryngeal mucosa epithelium.This marker can be useful for isolate epithelium stem cells and tissue engineering reconstruction.The abnormal expression and diffusely distribution in laryngeal mucosa can be used as a sensitive marker for malignant transformation.P75NTR staining have a good value to determine the surgical safe edge for laryngocarcinoma.In well-differentiated tumors,p75NTR positive staining was apparent in the basilar part and infiltrative margin of cancer nest.In moderately differentiated tumors,p75NTR was expressed in wider range from the margin of the tumors furthermore p75NTR was diffusely distributed in poorly differentiated tumors. We conclude that p75NTR was high expressed in the immature cells of laryngocarcinoma and was negative in terminal differentiation cancer cells.The p75NTR positive cancer cells have high proliferation energy and self-renewal property,may be correlated with tumor stem cells.In short,the expression of NGF and it's p75 receptor can be useful to diagnose and analysis prognostic for laryngocarcinoma.Immunocytochemical stain revealed:A small part of laryngocarcinoma Hep2 cell were p75NTR positive.Many of p75NTR positive cells were in multiplicative division station.The p75NTR positive cancer cells may contain more fast-proliferating daughter cells.In DDP resistant Hep2 cells,p75NTR positive ratio was higher than nomal Hep2 cells.We infered that p75NTR positive cells were more resistant to chemotherapeutic agent,these cells may be closed to tumor stem cells.We used RNAi method to cut down p75NTR expression,and confirmed siRNA effectivity by realtime PCR and Western blot.Down regulation of p75NTR level resulted in Hep2 cell proliferate inhibition.By FCM detection,we find Hep2 cell blocked at G0-G1 phase after RNAi,and the multiplicative division cell ratio were downregulated.So the expression of p75NTR are useful to promote laryngocarcinoma cell growth.In conclusion,nerve growth factor and it's receptor p75 are close related to the carcinogenesis,development, metastasis or differentiation.The internal regulation mechanism and possibility for gene therapy required more investgation.