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

描述（由申请人提供）：炎症性乳腺癌（IBC）是乳腺癌中最致命的形式之一，患者在接受手术或放射治疗时，五年以上的生存率低于5%。IBC细胞分泌分化因子，刺激血管发生，并作为位于新生血管内的肿瘤栓子侵入。在IBC中，栓子在其移动通过血管并停留在真皮淋巴结内时保持细胞-细胞附着，从而引起IBC炎性表型。尽管决定IBC侵袭的分子变化仍有待充分阐明，但IBC细胞系和人组织过表达E-钙粘蛋白、表皮生长因子受体（EGFR）和人表皮生长因子2（HER 2）（它们是与维持肿瘤球状体完整性相关的细胞表面蛋白）增加IBC肿瘤生长速率以及侵袭和转移。由于IBC肿瘤细胞栓子在形成转移方面更有效，并且比单细胞对化疗和放疗更具抗性，因此用具有分解细胞球状体的能力的化合物预防IBC似乎是可行的。我们最近发表了灵芝（灵芝），一种用于传统中药的蘑菇，选择性地抑制IBC细胞的活力，但不抑制非癌性乳腺上皮细胞的活力。另外我们 已经显示灵芝抑制在IBC进展和肿瘤球体形成中重要的关键蛋白质的表达。本提案的主要假设是灵芝抑制细胞表面蛋白质表达，这有助于在IBC进展期间产生的肿瘤球体的崩解，导致侵袭抑制与改变的细胞内信号传导相结合。本实验室的初步研究结果表明：1）灵芝在体内和体外均能下调多种促癌分子的表达，2）灵芝能抑制EGFR和E-cadherin蛋白的表达。3)灵芝抑制严重联合免疫缺陷（SCID）小鼠的IBC肿瘤生长和肿瘤重量分别为58%和45%。我们认为灵芝下调了参与IBC进展的细胞表面蛋白的表达，并使IBC细胞对EGFR/HER 2治疗具有化学敏感性。因此，本提案的主要目标是验证灵芝通过抑制质膜（PM）蛋白和随后的EGFR细胞内信号传导事件对IBC进展的抑制作用。为了验证我们的假设，我们提出1）分离和鉴定非癌乳腺上皮细胞和用灵芝处理的IBC细胞中的PM蛋白，和2）研究灵芝在IBC细胞中的治疗潜力，重点是EGFR/HER 2信号级联。IBC的分子机制的拟议解剖，预计将显着推进目前的理解和IBC的靶向治疗药物的发展，以及有助于这种致命的疾病的快速和准确的诊断。

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.