Al-Astani Tengku Din Tengku Ahmad Damitri, Shamsuddin Shazana Hilda, Idris Fauziah Mohamad, Ariffin Wan Mansor Wan Nor, Abdul Jalal Muhammad Irfan, Jaafar Hasnan
Department of Pathology, School of Medical Sciences, Universiti Sains Malaysia, Kelantan, Malaysia E-mail :
Asian Pac J Cancer Prev. 2014;15(9):3939-44. doi: 10.7314/apjcp.2014.15.9.3939.
To elucidate the role of rapamycin and PF4 on apoptosis regulation via Bax (pro-apoptosis), Bcl-2 (anti-apoptosis) and survivin activation on the growth in the 1-methyl-1-nitrosourea -induced invasive breast carcinoma model.
Thirty five female Sprague Dawley rats at age 21-day old were divided into 4 groups; Group 1 (control, n=10), Group 2 (PF4, n=5), Group 3 (rapamycin, n=10) and Group 4 (rapamycin+PF4, n=10). MNU was administered intraperitionally, dosed at 70 mg/kg body weight. The rats were treated when the tumors reached the size of 14.5 ± 0.5 mm and subsequently sacrificed after 5 days. Rapamycin and PF4 were administered as focal intralesional injections at the dose of 20 μg/lesion. The tumor tissue was then subjected to histopathological examinations for morphological appraisal and immunohistochemical assessment of the pro-apoptotic marker, Bax and anti-apoptotic markers, Bcl-2 and survivin.
The histopathological pattern of the untreated control cohort showed that the severity of the malignancy augments with mammary tumor growth. Tumors developing in untreated groups were more aggressive whilst those in treated groups demonstrated a transformation to a less aggressive subtype. Combined treatment resulted in a significant reduction of tumor size without phenotypic changes. Bax, the pro-apoptotic marker, was significantly expressed at higher levels in the rapamycin-treated and rapamycin+PF4-treated groups compared to controls (p<0.05). Consequently, survivin was also significantly downregulated in the rapamycin-treated and rapamycin+PF4-treated group and this was significantly different when compared to controls (p).
In our rat model, it could be clearly shown that rapamycin specifically affects Bax and survivin signaling pathways in activation of apoptosis. We conclude that rapamycin plays a critical role in the induction of apoptosis in MNU-induced mammary carcinoma.
在1-甲基-1-亚硝基脲诱导的浸润性乳腺癌模型中，阐明雷帕霉素和PF4通过促凋亡蛋白Bax、抗凋亡蛋白Bcl-2和生存素激活对细胞凋亡调控及肿瘤生长的作用。
将35只21日龄的雌性斯普拉格-道利大鼠分为4组；第1组（对照组，n = 10），第2组（PF4组，n = 5），第3组（雷帕霉素组，n = 10）和第4组（雷帕霉素+PF4组，n = 10）。腹腔注射MNU，剂量为70 mg/kg体重。当肿瘤达到14.5±0.5 mm大小时对大鼠进行治疗，随后在5天后处死。雷帕霉素和PF4以20 μg/病灶的剂量进行局部瘤内注射。然后对肿瘤组织进行组织病理学检查，以评估形态学，并对促凋亡标志物Bax以及抗凋亡标志物Bcl-2和生存素进行免疫组化评估。
未治疗的对照组队列的组织病理学模式显示，恶性程度随乳腺肿瘤生长而增加。未治疗组中发生的肿瘤更具侵袭性，而治疗组中的肿瘤则表现为向侵袭性较小的亚型转变。联合治疗导致肿瘤大小显著减小，且无表型变化。与对照组相比，促凋亡标志物Bax在雷帕霉素治疗组和雷帕霉素+PF4治疗组中显著高表达（p<0.05）。因此，生存素在雷帕霉素治疗组和雷帕霉素+PF4治疗组中也显著下调，与对照组相比有显著差异（p）。
在我们的大鼠模型中，可以清楚地表明雷帕霉素在激活细胞凋亡过程中特异性地影响Bax和生存素信号通路。我们得出结论，雷帕霉素在MNU诱导的乳腺癌细胞凋亡诱导中起关键作用。
