HUMSC介导的NHL“双靶向免疫治疗”及机制研究

Non-hodgkin's lymphoma (NHL) is a high incidence of lymphoid tissue malignant tumor with poor prognosis and 95% NHL cells express CD19,CD20 antigen. Our previous research have proved that combination anti-CD3/anti-CD19 bispecific antibody with ex4-1 BBL/anti-CD20 fusion protein for NHL treatment has obtained the good effect, but exists the risk of the immune system nonspecific activation. In recent years,human umbilical cord mesenchymal stem cells (HUMSCs) was believed to be one of the ideal drug carriers with ability of homing tumor site.Therefore, this research integrated the above protein drugs gene to HUMSC genome by lenti virus and sustained expressing exogenous genes after HUMSC homing to the tumor site.We produced high concentration drugs which mediated T cell activation and CD19 + CD20 + cells targeted clear within the tumor microenvironment at the first time,which effectively avoid the interference of targeted therapy by normal cell surface CD19, CD20 antigen and drug dose dependent toxicity caused by individualized differences. This "double targeting" strategy conformed to the requirement of future multiple targets tumor therapy, or as a new clinical treatment of NHL and other tumors.

非霍奇金淋巴瘤（NHL）是发病率高、预后差的淋巴组织恶性肿瘤, 95%NHL细胞表达CD19和CD20抗原。本课题组前期联合抗CD3/抗CD19双特异抗体与ex4-1BBL/抗CD20融合蛋白治疗NHL取得了较好效果,但药物全身分布存在非特异激活全身免疫系统的风险。近年发现，脐带间充质干细胞（HUMSCs）能向肿瘤部位归巢，是理想的体内药物载体之一。因此，本研究经慢病毒整合上述两种蛋白药物基因到HUMSC基因组，利用HUMSC向肿瘤部位归巢并持续分泌表达外源基因的能力，实现了免疫活性药物在肿瘤微环境内的特异性、高浓度分布，使其介导的T细胞激活和CD19+CD20+细胞靶向杀伤仅仅局限于肿瘤局部，从而有效避免了正常细胞表面CD19、CD20抗原对靶向治疗的干扰及个体化差异导致的药物剂量依赖毒性。这一“双靶向”概念很好的体现了未来肿瘤多靶点治疗的理念，或成为NHL等肿瘤的新的临床治疗手段。

B-NHL是一组起源于淋巴结和其他淋巴组织的恶性肿瘤，虽然基于美罗华的抗体靶向治疗取得较高的完全缓解率，但在临床上仍有超过50%患者对美罗华产生耐药，导致复发或者转移。本课题前期研究发现HUMSC具有向肿瘤炎性环境趋化的能力，是肿瘤免疫治疗策略的重要体内载体。我们成功构建了慢病毒表达载体pLentiR.SV40-Tandab(CD3/CD19)感染HUMSC，在肿瘤部位正确表达后蛋白能特异性结合CD19阳性肿瘤细胞和CD3阳性T细胞，激活的T细胞表面活化标志CD69和CD25及细胞因子（IL-2、IFN-γ、TNF-α）均明显升高，Raji皮下移植瘤的杀伤达到60.6 ± 5.7 %。联用D-1MT后，T细胞无能相关基因CD98和Jumonji的表达水平明显降低，对Raji移植瘤的生长具有更加明显的抑制作用。本课题证明人UC-MSCs作为一种治疗B-NHL的运载工具细胞，可以在肿瘤局部有效分泌Tandab(CD3/CD19)，联合应用D-1MT进一步提高募集的T细胞抑制Raji细胞移植瘤生长的作用。HUMSC运载基因工程抗体联合免疫调节药物是一种临床肿瘤免疫治疗的可行性新策略。