近年來研究發現，癌細胞當中有一小部分細胞具有幹細胞的特性且有助於腫瘤的進展和轉移，稱為癌症幹細胞，而此細胞的產生可能是由於骨髓間質幹細胞與癌細胞之間的訊息傳遞與物質交換進而導致表型的轉變。研究證明，當骨髓間質幹細胞移動至癌細胞附近，細胞間會透過多種方式進行訊息傳遞、促使腫瘤轉移。例如，細胞間相連的通道能夠遞送粒線體以及小分子核糖核酸。然而，骨髓間質幹細胞和肺癌細胞之間是否能藉由此通道影響表型仍然未知。在本研究當中，間質幹細胞與使用CRISPR / Cas9剃除癌症幹細胞相關基因ELAVL1的肺癌細胞HM20共同培養，以研究這兩種細胞株是否能夠形成相連的通道，並且傳遞ELAVL1(HuR)蛋白質進而使癌細胞具有幹細胞的特性。在細胞共同培養24小時後，細胞通道在兩細胞株間形成且利用其傳遞HuR。接下來，將Latrunculin A (細胞通道抑製劑）加入剔除ELAVL1 的HM20細胞中以探討細胞通道的影響，並在共同培養細胞後，利用流式細胞儀細胞儀分選出剔除ELAVL1 的HM20細胞，比較不同數量的細胞通道對癌症幹細胞表型的影響。藉由反轉錄聚合酶連鎖反應，我們發現共同培養後使得剔除ELAVL1 的HM20細胞的癌症幹細胞特性增強，而在加入細胞通道抑制劑後反轉了這個現象。總結上述實驗，此研究證明了HuR蛋白質能透過骨髓間質幹細胞與剔除ELAVL1 的HM20肺癌細胞之間的細胞通道傳遞，並可能更進一步的調節下游癌症幹細胞的相關基因。

Recent studies indicate that cancer stem cells (CSCs), a small population of cancer cells, contribute to tumor progression and metastasis. A potential factor of stem cell-like properties might be cross-talk between mesenchymal stem cells (MSCs) and cancer cells. Research has suggested that the recruitment of MSCs to cancer cells may regulate tumor metastasis through several signal pathways. Also, tunneling nanotubes (TNTs) are implicated in the transfer of mitochondria and miRNA between normal cells and cancer cells subsequently metastasis. However, it remains unknown whether the TNTs formation between -MSCs and lung cancer cells can modulate the CSC properties. In this study, MSCs were isolated from human bone marrow of volunteers, and co-cultured with ELAVL1-knockout (by CRISPR/Cas9-mediated genome editing) HM20 lung cancer cells to investigate whether TNTs could form and ELAVL1 (HuR, a CSC-related protein) was transferred from MSCs to HuR-knockout HM20 cells and upregulated the CSCs properties through TNTs. First, the formation of TNTs and HuR transfer were observed after 24 hours after co-culture. Next, HuR-knockout HM20 cells were treated with Latrunculin A (a TNT inhibitor) to inhibit the formation of TNTs to examine the effects of TNTs. After co-culture, HuR-knockout HM20 cells were sorted with a flow cytometry cell sorter to compare the impact of different amount of TNTs on the CSCs phenotype. Through RT-PCR, we found that the CSC properties were enhanced in HuR-knockout HM20 cells after co-culture compared to HuR-knockout HM20 cells only, whereas the effects were reduced in TNTi-treated cells. In summary, we illustrated that MSCs and HuR-knockout HM20 cells are connected by TNTs after 24hr co-culture. Consequently HuR is transferred from MSCs to HuR-knockout HM20 cells and is likely to control downstream genes related to CSCs.

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