Clinical And Pathological Observation On Neurophilic Invasion Of ACC And Preliminary Abstraction Of Corresponding Secreted Proteins

Adenoid cystic carcinoma shows a strong tendency to neurophilic invasion. It metastizes very early through nerves which is responsible for the high recurrent rate and poor prognosis. Many researches have been carried out to illuminate the mechanism and the invasive pathway, yet to date there has been no studies that clearly explain it. Some scholars hypothesized that the neurophilic characteristics of ACC is due to special microenvironment where exits a space around nerve along which ACC infiltrates. But which cytokine plays the most important role? There has been no report about it. This study aimed to separate and purify the secreted protein of ACC which has the possible function to stimulate the outgrowth of neuronal processes. Achievement of the research will shed light on the mystery of the mechanism of neurophilic characteristics of ACC.First, medical records of ACC during 1994 and 2006 which involved in neurophilic invasion were reviewed and patients' specimens were studied by light microscopy and transmission electron microscopy (TEM). The invasive pathway of ACC was observed through perineural space and corresponding pathologic changes, also there exited numerous small nerve sections in the histopathologic slides of tumor entities. So we hypothesized that ACC could secrete some neurotrophic factors to guide peripheral nerves gemmation and to trigger the cascade of the neural invasion in succession.To explore the close relationship between SACC-83 and neural tissue, co-culture model of SACC-83 cells and dorsal root ganglia was successfully constructed. In the model, SACC-83 cells produced a suitable microenvironment in which neuronal processes remarkablly growed. Then DRG were cultured in the conditioned medium of SACC-83. Compared with cellular lysate, pure DMEM, DMEM containing serum and conditioned medium of other cells, the group ofconditioned medium from SACC-83 manifested obvious promotive effects on DRG, confirmed that SACC-83 could secrete some special growth factors which had promotive effects on outgrowth of neuronal processes.In order to extract the exact factors which exerted the stimulative effect on peripheral nerve gemmation, secreted proteins in the conditioned medium were extracted and refined by salting-out, gel chromatography and ion exchange chromatography, and neural cell culture techniques subsequently to screen secreted functional proteins of ACC. After finding the general secreted proteins of SACC-83 which had promotive effects on outgrowth of neuronal processes, we had confirmed that proteins of interest were above 43kDa the molecular weight, also with neutral or alkaline nature. The exact factors remain refining.