间充质干细胞（MSCs）由于其定位能力和通过病毒或非病毒方法进行基因操作的潜力，被视为癌症治疗的有前途的载体。白细胞介素-12（IL-12）是关键的免疫调节细胞因子之一，具有抗肿瘤效应。然而，治疗剂量下的系统给药会导致宿主系统高水平干扰素-γ（IFN-γ）诱导的严重毒性。本研究旨在研究基因工程的人脐带来源的间充质干细胞（hUCMSC）在H1975人肺腺癌细胞上表达IL-12对其体外生长的抑制作用。比较了腺病毒法和电穿孔法生成hUCMSC-IL12的效果，选择效果更好的方法生成与H1975或MRC-5细胞共培养的hUCMSC-IL12进行实验。对hUCMSC和hUCMSC-IL12进行了表征。腺病毒法在转染效率（63.6%）、转染后细胞存活率（82.6%）和hIL-12蛋白表达（1.2 x 107 pg/ml）方面表现出优越结果，因此选择该方法进行下游实验。随后，在共培养5天后，hUCMSC-IL12对H1975细胞显示出明显的抑制作用。对于所有其他共培养组别，均未观察到显著差异，表明抑制作用是由hIL-12引起的。最后，通过检查它们的表面标记和分化特性，确定hUCMSC-IL12的完整性未受到转细胞的影响。本研究证实了hUCMSC可以基因工程表达hIL-12，对人肺腺癌细胞具有直接的生长抑制作用的概念。

Mesenchymal stromal cells (MSCs) are promising vehicles for cancer therapy due to their homing ability and potency to be genetically manipulated through either viral or non-viral methods. Interleukin-12 (IL-12) is one of the key immunomodulatory cytokines which has anti-tumour effect. However, systemic administration of the cytokine at therapeutic dosage can cause serious toxicity in the host system due to the high systemic level of interferon-γ (IFN-γ) induced.This study aimed to investigate the in vitro growth inhibition of genetically engineered human umbilical cord-derived mesenchymal stromal cells (hUCMSC) expressing IL-12 on H1975 human lung adenocarcinoma cells.Both adenoviral method and electroporation which used to generate hUCMSC-IL12 were compared. The method with better outcome was selected to generate hUCMSC-IL12 for the co-culture experiment with H1975 or MRC-5 cells. Characterisation of hUCMSC and hUCMSC-IL12 was performed.Adenoviral method showed superior results in transfection efficiency (63.6%), post-transfection cell viability (82.6%) and hIL-12 protein expression (1.2 x 107 pg/ml) and thus was selected for the downstream experiments. Subsequently, hUCMSC-IL12 showed significant inhibition effect on H1975 cells after 5 days of co-culture. No significant difference was observed for all other co-culture groups, indicating that the inhibition effect was because of hIL-12. Lastly, the integrity of hUCMSC-IL12 remained unaffected by the transduction through examination of their surface markers and differentiation properties.This study provided proof of concept that hUCMSC can be genetically engineered to express hIL-12 which exerts direct growth inhibition effect on human lung adenocarcinoma cells.