A biophysical stromal basis for radiation sensitivity in ductal carcinoma in situ

描述（由申请人提供）：乳腺癌的演变涉及上皮细胞和周围基质微环境之间复杂的相互作用。肿瘤进展与细胞外基质（ECM）的显著重塑有关，细胞外基质创造了一个有利于侵袭和迁移的支架。重塑后的ECM也明显比正常的更硬，并促进恶性转化和转移。我们假设ECM僵硬也调节对治疗的反应。ECM提供生化和生物物理线索，激活指导细胞命运的关键分子途径，这些线索主要通过整合素受体家族进行转导。确实，ECM张力增强整合素活性，刺激pi3 -激酶（PI3-k）信号传导诱导恶性转变，ECM刚度激活YAP-TAZ转录因子，增强肿瘤的恶性行为。因此，PI3-k和YAP-TAZ代表了驱动组织恶性行为的关键ECM激活分子机制，并可能为预测预后和治疗靶向提供新的机会。放射治疗通常用于治疗乳腺癌，然而，基质张力促进耐药的机制是一个创新的研究前沿，尚未被调查。我们的初步数据表明，高ECM刚度（4kPa）改变了恶性乳腺细胞对电离辐射（IR）的凋亡和增殖反应，并揭示了这与YAP激活有关。同样重要和有趣的是张力在原位癌治疗抵抗中的作用。导管原位癌（Ductal carcinoma in situ， DCIS）由癌上皮细胞组成，这些细胞位于导管上皮腔内，但尚未侵入周围的间质。众所周知，ECM的活性重塑发生在原位病变周围的基质中，基质重塑导致组织力和胶原交联的增加，从而推动进展。dcis样病变的结构为研究导管中癌细胞与基质活化之间的相互作用提供了独特的机会，我们为此开发了原位疾病模型。我们假设激活的ECM基质的高张力通过直接参与YAP通路在癌上皮细胞的存活和增殖中起着关键作用，并且从激活的基质中释放促生存的机械信号是提高治疗效果的一种有希望的方法。我们的目标是通过以下测试来确定ECM张力是否以及如何特异性调节IR治疗耐药性：1)YAP通路是否在IR介导的细胞死亡和增殖中独立作用；2)以及整合素机械信号是否改变了这一调节。此外，我们有独特的机会来研究临床DCIS中基质生物物理和形态学特征是否与YAP信号和疾病进展相关。

DESCRIPTION (provided by applicant): The evolution of breast cancer involves a complex interplay between the epithelial cells and the surrounding stromal microenvironment. Tumor progression is associated with marked remodeling of the extracellular matrix (ECM), which creates a scaffold that favors invasion and migration. The remodeled ECM is also significantly stiffer than normal, and promotes malignant transformation and metastasis. We hypothesize that ECM stiffness also regulates response to therapy. The ECM provides biochemical and biophysical cues that activate key molecular pathways that direct cell fate and these cues are primarily transduced through the integrin family of receptors. Indeed, ECM tension enhances integrin activity and stimulates PI3-kinase (PI3-k) signaling to induce malignant transition, and ECM stiffness activates the YAP-TAZ transcription factors to enhance the malignant behavior of tumors. As such, PI3-k and YAP-TAZ represent key ECM activated molecular mechanisms that drive the malignant behavior of tissues and could provide novel opportunities for predicting prognosis and therapeutic targeting. Radiation therapy is commonly used to treat breast cancer, however, knowledge of the mechanisms by which stromal tension act to promote resistance is an innovative front of research, and yet uninvestigated. Our preliminary data indicate that high ECM stiffness (4kPa) modifies the apoptotic and proliferative response to ionizing radiation (IR) in malignant breast cells, and reveal that this is associated with YAP activation. Equally important and interesting is the role of tension in therapy resistance in in situ cancer. Ductal carcinoma in situ (DCIS) is comprised of cancerous epithelial cells that reside within the ductal epithelial compartment without yet having invaded into the surrounding stroma. It is well known that active remodeling of the ECM, occurs in the stroma surrounding in situ lesions and that stromal remodeling leads to increased tissue force and collagen-cross-linkingthat drives progression. The architecture of DCIS-like lesions provides unique opportunities to investigate the interplay between cancer cells residing in the duct and stromal activation, and we have developed models of in situ disease for this purpose. We hypothesize that the high tension of an activated ECM stroma plays a critical role in the survival and proliferation of cancerous epithelia cells through direct engagement of the YAP pathways, and that disengaging pro-survival mechanosignaling emanating from the activated stroma is a promising approach towards enhancing therapeutic efficacy. Our goals are to determine if and how ECM tension specifically regulates IR therapy resistance by testing 1) whether the YAP pathways are acting independently in IR- mediated cell death and proliferation; 2) and whether integrin mechanosignaling modifies this regulation. In addition, we have the unique opportunity to investigate whether stromal biophysical and morphological features are associated YAP signaling and disease progression in clinical DCIS.