Role of Reishi on cell surface proteins and signaling modulation in IBC

描述(申请人提供)：炎症性乳腺癌(IBC)是最致命的乳腺癌形式之一，患者在接受手术或放射治疗时，五年后的存活率不到5%。IBC细胞分泌分化因子，刺激血管生成，并以新生血管内肿瘤栓子的形式侵袭。在IBC中，栓子在穿过血管并滞留在真皮淋巴结内时维持细胞间的附着，导致IBC的炎症表型。尽管决定IBC侵袭的分子变化仍未完全阐明，但IBC细胞系和人类组织过度表达E-钙粘素、表皮生长因子受体(EGFR)和人表皮生长因子2(HER2)，这些细胞表面蛋白与维持肿瘤球体完整性、提高IBC肿瘤生长速度以及侵袭和转移有关。由于IBC肿瘤细胞栓子比单一细胞更有效地形成转移，并且对化疗和放疗的抵抗力更强，因此似乎可以用一种能够分解细胞球体的化合物来预防IBC。我们最近发表了灵芝(灵芝)，一种传统的中药蘑菇，选择性地抑制IBC细胞的活性，但不抑制非癌乳腺上皮细胞的活性。另外，我们 研究表明，热石抑制了IBC进展中重要的关键蛋白的表达，并抑制了肿瘤球体的形成。本方案的主要假设是Reishi抑制细胞表面蛋白的表达，这有助于IBC进展过程中产生的肿瘤球体的解体，导致侵袭抑制与细胞内信号变化相结合。为了支持这一假说，我们实验室的初步研究表明，热石1)下调一些促癌分子的表达，2)在体外和体内抑制EGFR和E-钙粘蛋白的蛋白丰度。3)热石对严重联合免疫缺陷(SCID)小鼠的IBC瘤生长和瘤重的抑制作用分别为58%和45%。我们认为热石下调参与IBC进展的细胞表面蛋白的表达，并使IBC细胞对EGFR/HER2治疗具有化疗敏感性。因此，本研究的主要目的是通过抑制质膜(PM)蛋白和随后的EGFR细胞内信号事件来验证Reishi对IBC进展的抑制作用。为了验证我们的假设，我们建议1)分离和鉴定非癌乳腺上皮细胞和经Reishi处理的IBC细胞中的PM蛋白；2)研究Reishi对IBC细胞的治疗潜力，重点是EGFR/HER2信号转导通路。对IBC分子机制的研究有望极大地促进当前对IBC靶向治疗药物的理解和发展，并有助于对这种致命疾病的快速和准确诊断。

DESCRIPTION (provided by applicant): Inflammatory Breast Cancer (IBC) is one of the most lethal forms of breast cancer, where patients show less than a five percent survival rate beyond five years when treated with surgery or radiation therapy. IBC cells secrete differentiation factors, stimulate vasculogenesis, and invade as tumor emboli located within a de novo formed vessel. In IBC, the embolus maintains cell-cell attachments as it moves through the vessel and lodges within a dermal lymph node, causing the IBC inflammatory phenotype. Although the molecular changes that dictate IBC invasion remain to be fully elucidated, IBC cell lines and human tissues, overexpress E-cadherin, Epidermal Growth Factor Receptor (EGFR), and Human Epidermal Growth Factor 2 (HER2) which are cell surface proteins associated with maintaining tumor spheroid integrity, increase IBC tumor growth rate, and invasion and metastasis. Since IBC tumor cell emboli are more efficient at forming metastases and are more resistant to chemo and radiotherapy than single cells, it seems feasible to prevent IBC with a compound that has the ability to disintegrate the cell spheroids. We recently published that Ganoderma lucidum (Reishi), a mushroom used in Traditional Chinese Medicine, selectively inhibits IBC cell viability, but not viability of non- cancerous mammary epithelial cells. Also, we have shown that Reishi inhibits the expression of key proteins important in IBC progression, and tumor spheroid fomation. The main hypothesis of the present proposal is that Reishi inhibits cell surface protein expression, which contributes to disintegration of the tumor spheroids that are created during IBC progression, resulting in invasion inhibition combined with altered intracellular signaling. In support of this hypothesis, preliminary studies in our laboratory showe that Reishi 1) downregulates a number of cancer promoting molecules, 2) Reishi inhibits EGFR and E-cadherin protein abundance in vitro and in vivo. 3) Reishi inhibits IBC tumor growth and tumor weight in severe combined immunodeficient (SCID) mice by 58% and 45%, respectively. We propose that Reishi downregulates the expression of cell surface proteins involved in the progression of IBC and chemosensitize the IBC cells to EGFR/HER2 therapy treatment. Therefore, the main goal of this proposal is to validate the inhibitory role of Reishi on IBC progression via the inhibition of plasma membrane (PM) proteins and subsequent EGFR intracellular signaling events. To test our hypothesis, we propose 1) to isolate and identify PM proteins in non- cancerous mammary epithelial cells and in IBC cells treated with Reishi and 2) to investigate the therapeutic potential of Reishi in IBC cells, focusing on EGFR/HER2 signaling cascades. The proposed dissection of the molecular mechanisms of IBC is expected to significantly advance the current understanding and development of targeted therapeutic agents for IBC as well as contribute to a rapid and accurate diagnosis of this mortal disease.