基于p21途径探讨组蛋白去乙酰化酶抑制剂SAHA对化疗耐药B细胞淋巴瘤的影响及在化疗增敏中的作用

The resistance to chemotherapy in patients with relapsed/refractory B cell lymphoma is the treatment of intractable problems. Up to now, histone deacetylase inhibitor (SAHA) has been approved by FDA for relapsed/refractory cutaneous T cell lymphoma，preclinical studies about this drug in the treatment of relapsed/refractory B cell lymphoma patients are still rare.In current study, we found that SAHA therapy resistant B -cell lymphoma cell lines. Detailed in the mechanism, we found the single dosage of SAHA did induce apoptosis in therapy resistant B-cell lymphoma, but caused G1 cell cycle arrest along with significantly increased p21 protein expression.Furthermore, SAHA had a synergistic effect with etoposide, cisplatin and gemcitabine，SAHA inhibited proliferation of primary lymphoma cells derived from relapsed/refractory patient. .Based on these evidences, we proposed: SAHA enhanced chemotherapy efficacy in treatment-resistant lymphoma in a p21-depednet manner. By using B-cell lymphoma therapy-resistant cell lines, mouse B-cell lymphoma xenograft model and RNA interference, flow cytometry, Western blot etc., We are trying to explore the mechanism of SAHA alone and combined with chemo to overcome the therapy-resistant B-NHL. It will provide us an in depth of molecular basis for the clinical application of SAHA in relapsed/refractory B-cell lymphoma patients.

复发/难治B细胞淋巴瘤的化疗耐药是治疗难题。FDA已批准组蛋白去乙酰化酶抑制剂（SAHA）用于复发/难治皮肤T细胞淋巴瘤治疗。临床前研究提示其对B细胞淋巴瘤有效，但SAHA对化疗耐药B细胞淋巴瘤的作用尚未阐明。申请者前期发现SAHA能有效抑制化疗耐药B细胞淋巴瘤细胞株增殖，并在复发/难治患者组织来源肿瘤细胞中被证实。后发现SAHA不增加耐药细胞株凋亡，但引起G1细胞周期阻滞和调控G1期的p21蛋白明显增加。进一步发现SAHA能对依托泊甙、吉西他滨、顺铂产生化疗增敏。据此提出“SAHA单药可通过p21途径，提高耐药B细胞淋巴瘤周期阻滞，从而抑制增殖，并增敏化疗”假说。拟采用化疗耐药B细胞淋巴瘤的细胞株和小鼠模型、RNA干扰等，从细胞及动物水平探讨SAHA单药和与化疗联合对化疗耐药B细胞淋巴瘤的作用机制，为今后SAHA治疗复发/难治B细胞淋巴瘤的临床应用提供前期理论依据。

背景:复发/难治B细胞淋巴瘤的化疗耐药是治疗难题。FDA已批准组蛋白去乙酰化酶抑制剂（SAHA）用于复发/难治皮肤T细胞淋巴瘤治疗。临床前研究提示其对B细胞淋巴瘤有效，但SAHA对化疗耐药B细胞淋巴瘤的作用尚未阐明。主要研究内容:SAHA单药以及联合化疗对耐药B细胞的作用，以及p21所起的作用。重要结果、关键数据：我们发现SAHA能有效抑制化疗耐药B细胞淋巴瘤细胞株增殖，并能抑制复发/难治患者组织来源肿瘤细胞的生长。SAHA不增加耐药细胞株凋亡，但引起G1细胞周期阻滞和调控G1期的p21蛋白明显增加。RNA-sequece提示SAHA处理前后，E2F的表达差异变化大。进一步发现SAHA能对依托泊甙、吉西他滨、顺铂产生化疗增敏。SAHA联合化疗后引起p21表达增加，以及相应的p27表达增加和cyclin B1表达的下调。p21在单药和联合用药中可能起重要作用。科学意义：为今后SAHA治疗复发/难治B细胞淋巴瘤的临床应用提供前期理论依据。