1131

CHRM3

cholinergic receptor, muscarinic 3;CHRM3;cholinergic receptor, muscarinic 3

acetylcholine receptor, muscarinic 3|m3 muscarinic receptor|muscarinic acetylcholine receptor M3

1q43

protein-coding

BACKGROUND: Cholangiocarcinoma, a type of malignant tumor, originates from epithelial cells of the bile duct. Perineural invasion is common path for cholangiocarcinoma metastasis, and it is highly correlated with postoperative recurrence and poor prognosis. It has been reported that muscarinic acetylcholine receptor M3 (mAChR M3) is widely expressed in digestive tract cancer, and may play an important role in the proliferation, differentiation, transformation and carcinogenesis of tumors. This study was to explore the effect of mAChR M3 on the growth of cholangiocarcinoma cells in vitro and provide a new approach to the pathogenesis and treatment of cholangiocarcinoma. METHODS: Streptavidin-biotin complex immunohistochemistry was carried out to assess the expression of mAChR M3 in surgical specimens of cholangiocarcinomas (40 cases) and normal bile duct tissues (9), as well as to investigate nerve infiltration. The cholangiocarcinoma cells were treated with different concentrations of selective M-receptor agonist pilocarpine and M-receptor blocker atropine sulfate to induce changes in cell proliferation. The experimental data were analyzed by the Chi-square test. RESULTS: The strongly-positive expression rate of mAChR M3 was much higher in poorly-differentiated (69%, 9/13) than in well- and moderately-differentiated cholangiocarcinomas (30%, 8/27) (X2=5.631, P<0.05). The strongly-positive mAChR M3 expression rate in hilar cholangiocarcinoma (50%, 14/28) was higher than that in cholangiocarcinomas from the middle and lower common bile duct (25%, 3/12) (X2=2.148, P<0.05). Cholangiocarcinomas with distant metastasis had a strongly-positive expression rate (75%, 9/12), which was much higher than those without distant metastasis (29%, 8/28) (X2=7.410, P<0.01). The absorbance value in the pilocarpine+atropine group was significantly higher than the corresponding value in the pilocarpine group. CONCLUSIONS: The expression of mAChR M3 is influenced by the extent of differentiation, distant metastasis and the site of cholangiocarcinoma. It also plays a key role in the proliferation and metastasis of cholangiocarcinoma.

INTRODUCTION: Chronic obstructive pulmonary disease (COPD) is an independent risk factor for lung cancer development, but the mechanism is not fully understood. Muscarinic receptor 3 (M3R) has been found to be involved in the progression of small-cell lung cancer and the pathological process of COPD. We hypothesized that M3R may contribute to lung cancer development, especially in patients with COPD. METHODS: The correlation between M3R expression and clinical features of non-small-cell lung cancer (NSCLC) was evaluated in 148 paraffin-embedded archived NSCLC specimens with the use of immunohistochemistry. M3R agonist and siRNA treatments were used to study the role of M3R in NSCLC cell lines. Western blotting and zymography were used to examine the impact of M3R on the PI3K/Akt/matrix metalloproteinase 9 signaling pathway. RESULTS: The expression of M3R in NSCLC was significantly increased and correlated with tumor metastasis and poor survival of NSCLC patients. NSCLC patients with COPD showed higher expression of M3R than those without COPD (p = 0.0014). Moreover, M3R expression was inversely related to percent forced expiratory volume in 1 second (r = 0.7017, p < 0.0001) and forced expiratory volume in 1 second /forced vital capacity (r = 0.5057, p < 0.0001), but positively related to smoking history. Down-regulation of M3R resulted in the inhibition of migration and invasion ability of NSCLC cell lines A549 and L78. Furthermore, M3R enhanced the expression and activity of matrix metalloproteinase 9 through PI3K/Akt, which promoted the migration and invasion of NSCLC cell lines. CONCLUSION: Our results suggest that overexpression of M3R in NSCLC promotes the progression of NSCLC, which could contribute to lung cancer development in COPD patients. M3R could be another pharmacological target in lung cancer, especially in COPD patients.