MOLECULAR BASIS FOR THE IMPACT OF SEX ON BRAIN TUMORIGENESIS

描述（由申请人提供）：原发性和转移性脑肿瘤在男性中比女性更常见。无论年龄或地区如何，这都是正确的。因此，性别一定影响中枢神经系统肿瘤生长的基本机制。在初步研究中，我们建立了导致雄性星形胶质细胞转化而不是雌性星形胶质细胞的条件。这个实验范例是一个前所未有的机会来定义性别对肿瘤发生的影响的分子基础。我们发现，性别影响整体基因表达、肿瘤抑制因子p21cip1的激活、干细胞表型的诱导、生长动力学、细胞衰老和颅内恶性生长模式。此外，我们还发现了人类GBM干细胞的性别差异。在这个建议中，我们将利用这些小鼠和人类GBM模型来定义性别对脑肿瘤发生影响的分子基础。在Specific Aim 1中，我们建立在初步发现的基础上，生长抑制分子p202的两性二型表达导致肿瘤抑制因子p21cip1的差异诱导，从而阻断女性星形胶质细胞的转化。在Specific Aim 2中，我们将继续研究表明男性星形胶质细胞更容易诱导干细胞，并定义性别、多个起始致癌事件、X染色体再激活和起源细胞如何相互作用来调节转化。在Specific Aim 3中，我们对人类男性和女性GBM干细胞培养进行了验证研究，并验证了GBM干细胞的性别差异将影响CXCR4治疗靶向反应的假设。总之，这些研究将推进癌症生物学的基础知识，并有可能影响我们治疗恶性脑肿瘤患者的方法。

DESCRIPTION (provided by applicant): Primary and metastatic brain tumors occur more commonly in males than females. This is true regardless of age or region of the world. Thus, sex must affect fundamental mechanisms of neoplastic growth in the central nervous system. In preliminary studies we established conditions that result in the transformation of male but not female astrocytes. This experimental paradigm is an unprecedented opportunity to define the molecular basis for the effects of sex on tumorigenesis. We found that sex affects global gene expression, activation of the tumor suppressor p21cip1, induction of a stem cell phenotype, growth kinetics, cellular senescence and patterns of intracranial malignant growth. Moreover, we found sex differences in human GBM stem cells. In this proposal we will exploit these murine and human GBM models to define the molecular basis for the effect of sex on brain tumorigenesis. In Specific Aim 1 we build on preliminary findings that sexually dimorphic expression of the growth inhibitory molecule p202 results in differential induction of the tumor suppressor p21cip1 and thereby blocks transformation in female astrocytes. In Specific Aim 2 we will follow up on preliminary studies that indicate stem cells are more easily induced in male astrocytes and define how sex, multiple initiating oncogenic events, X chromosome reactivation and cell of origin interact to regulate transformation. In Specific Aim 3 we perform validation studies with human male and female GBM stem cell cultures and test the hypothesis that sex differences in GBM stem cells will impact on responses to therapeutic targeting of CXCR4. Together these studies will advance of fundamental knowledge of cancer biology and have the potential to impact on our approach to treating patients with malignant brain tumors.