The role of alphaB-crystallin in chemoresistance of retinoblastoma

描述(申请人提供)：细胞凋亡抑制物在许多疾病中普遍表达，赋予细胞存活和抵抗死亡的能力。小分子热休克蛋白AB-晶状体蛋白通过破坏caspase-3的激活来抑制细胞凋亡，caspase-3是细胞在凋亡过程中分解的关键酶。虽然已经确定AB-晶体蛋白在晶状体中表达，但最近在视网膜中发现了晶体蛋白蛋白，表明这些蛋白可能调节视网膜细胞的生存。由于AB-晶体蛋白在几种人类癌症(乳腺癌、前列腺癌和神经母细胞瘤)中表达，并且已知与多种化疗药物诱导的细胞凋亡抵抗相一致，我们预测这种热休克蛋白可能在视网膜母细胞瘤抵抗化疗诱导的细胞凋亡中起重要作用。视网膜母细胞瘤是儿童中最常见的眼癌，可导致严重的视力丧失，在某些情况下，甚至危及生命。目前的治疗方法是在放疗前使用化疗来缩小肿瘤大小。有必要缩小大肿瘤的大小，以便将照射剂量保持在儿童可以耐受的范围内。因此，视网膜母细胞瘤肿瘤细胞对化疗的耐药性是一个重要的临床问题。我们推测，在视网膜母细胞瘤细胞中表达AB-晶体蛋白通过抑制caspase-3介导的细胞死亡来抵抗化疗诱导的细胞凋亡，选择性地抑制这种热休克蛋白将恢复对化疗的敏感性。这一假说将在三个特定目标下得到验证：(I)确定AB-晶体蛋白在视网膜母细胞瘤肿瘤切片和视网膜母细胞瘤细胞系中的表达；(Ii)确定AB-晶体蛋白是否在体外抑制各种化疗药物对视网膜母细胞瘤细胞的凋亡；(Iii)确定AB-晶体蛋白的特异性抑制是否使视网膜母细胞瘤细胞更容易受到化疗诱导的凋亡。这些研究将确定视网膜母细胞瘤化疗耐药的新标记物，并将导致未来针对AB-晶体蛋白的新治疗策略的研究。我们的长期目标是预防视力丧失，提高视网膜母细胞瘤患者的生活质量。作为学术研究促进奖，这项建议不仅将进一步研究视网膜母细胞瘤肿瘤细胞生物学，还将推进布里奇沃特州立学院合格本科生的生物研究培训，并让未来的科学家接触到令人兴奋的视野研究领域。R15学术研究增强奖AB-晶体蛋白在视网膜母细胞瘤化疗耐药中的作用项目叙述：这是第一个研究AB-晶体蛋白在眼部肿瘤中的作用的研究。我们将确定AB-晶体蛋白是否能阻止化疗药物诱导的视网膜母细胞瘤肿瘤细胞的凋亡。如果AB-晶体蛋白介导化疗耐药，这种蛋白可以被靶向并下调，使肿瘤细胞对治疗更敏感。我们的长期目标是预防视力丧失，提高视网膜母细胞瘤患者的生活质量。

DESCRIPTION (provided by applicant): Inhibitors of apoptosis are commonly expressed in many disorders, conferring cellular survival and resistance to death. The small heat shock protein aB-crystallin inhibits apoptosis by disrupting the activation of caspase-3, an enzyme that is critical for disassembly of the cell during apoptosis. While it is well established that aB-crystallin is expressed in the lens, crystallin proteins were recently identified in the retina, suggesting that these proteins may regulate retinal cell survival. Since aB-crystallin is expressed in several human cancers (breast, prostate and neuroblastoma) and is known to coincide with resistance to apoptosis induced by various chemotherapeutic agents, we predict that this heat shock protein may be important in the resistance to chemotherapy-induced apoptosis in retinoblastoma. Retinoblastoma, the most common eye cancer in children, can cause significant loss of vision and in some cases, is life-threatening. Current treatments use chemotherapy to reduce tumor size prior to irradiation. It is necessary to reduce the size of large tumors in order to keep the dose of irradiation within a range that can be tolerated by children. As such, resistance of retinoblastoma tumor cells to chemotherapy is a significant clinical problem. We hypothesize that expression of aB-crystallin in retinoblastoma cells confers resistance to chemotherapy-induced apoptosis by inhibiting caspase-3 mediated cell death, and that selective inhibition of this heat shock protein will restore chemosensitivity. This hypothesis will be tested in three specific aims (i) determine the expression of aB-crystallin in retinoblastoma tumor sections and in retinoblastoma cell lines; (ii) determine whether aB-crystallin inhibits apoptosis in retinoblastoma cells in vitro in response to various chemotherapeutic agents; (iii) determine whether specific inhibition of aB-crystallin makes retinoblastoma cells more susceptible to chemotherapy-induced apoptosis. These studies will identify a novel marker for chemotherapeutic resistance in retinoblastoma and will lead to future studies on novel treatment strategies that target aB-crystallin. Our long term goal is to prevent loss of vision and improve the quality of life for retinoblastoma patients. As an Academic Research Enhancement Award, this proposal will not only further research in retinoblastoma tumor cell biology, it will also advance the biological research training of qualified undergraduates at Bridgewater State College and expose future scientists to the exciting field of vision research. Merideth Kamradt Krevosky, R15 Academic Research Enhancement Award The role of aB-crystallin in chemoresistance of retinoblastoma Project Narrative: This is the first study in which the role of aB-crystallin in eye tumors will be studied. We will determine whether aB-crystallin prevents apoptotic cell death of retinoblastoma tumor cells induced by chemotherapeutic agents. If aB-crystallin mediates resistance to chemotherapy, this protein can be targeted and downregulated, making tumor cells more sensitive to treatment. Our long-term goal is to prevent loss of vision and to improve the quality of life for retinoblastoma patients.