Table 1.
Summary of some experimental studies indicating the modulatory effects of alpha7 nicotinic acetylcholine receptor (α7nAChR) in gastrointestinal cancers regulation.
| Cancer type | Function | Commentary | References |
|---|---|---|---|
| GC | Enhanced metastasis | Nicotine and its derived nitrosamine compound (i.e. NNK) through activation of α7nAChR-related signaling pathways significantly enhanced gastric cancer (GC) metastasis. | [56, 57] |
| GC | Induced proliferation | Exposure to nicotine and NNK via α7nAChR mechanisms significantly induced cell proliferation in the AGS cell line. | [58] |
| GC | Enhanced chemosensitivity | α7nAChR enhanced the sensitivity of cancerous cells to chemotherapeutic reagents including taxanes and ixabepilone. | [6, 59] |
| GC | Enhanced chemoresistance | Targeted delivery of siRNA against α7nAChR makes gastric tumor cells became more resistant to 5-FU treatment. | [73] |
| CRC | Induced proliferation | Nicotine promotes cell proliferation via α7nAChR in human colorectal cancer (CRC) cell line. | [7] |
| CRC | Enhanced migration | Nicotine and tobacco-specific carcinogen (NNK) enhanced CRC cells migration through α7nAChR-mediated mechanisms. | [42, 43] |
| CRC | Enhanced tumor growth | ACh itself via α7nAChR serves as an important autocrine/paracrine growth factor in the human colon adenocarcinoma cell line HT-29. | [44] |
| CRC | Suppressed tumorigenesis | Nicotine suppresses acute colitis and CRC associated with chronic colitis in mice an effect that attenuated by the antagonist of α7nAChR. | [49] |
| CRC | Suppressed metastasis | α7nAChR in tumor-associated macrophages inhibits CRC metastasis in both animal model and LoVo human CRC cell line. | [52, 53] |
| PC | Induced proliferation | Nicotine and its nitrosated carcinogenic derivatives, promote cell proliferation of pancreatic cancer (PC) through activation of α7nAChR. | [8] |
| PC | Induced CSCs renewal | Nicotine induces self-renewal of pancreatic cancer stem cells (CSCs) through α7nAChR dependent mechanisms. | [92] |
| PC | Enhanced metastasis | Nicotine and cigarette-smoke promote the metastasis of PC via α7nAChR downstream signaling cascades. | [93] |
| LC | Induced proliferation | Nicotine acts through α7nAChR to stimulate the cholangiocyte proliferation in a xenograft mice model of liver cancer (LC). | [78] |
| LC | Increased carcinogenesis | NNK through increased expression of α7nAChR caused hepatic damage and LC progression in an experimental animal model. | [79] |
| LC | Enhanced tumor growth | Nicotine-triggered α7nAChR activation promotes both in vitro and in vivo tumor growth of HCC cells. | [81] |