The Importance of EMT in Breast Cancer in African American Women

描述（由申请人提供）：我们的实验室发现了一种基因BP1，它在89%的非裔美国女性（AAW）的肿瘤中被激活，而在白人女性（CW）的肿瘤中被激活的比例为57%。高水平的BP1表达与侵袭性和较大的肿瘤有关。AAW的肿瘤也具有侵袭性——更高的分级、更大、更常见的雌激素受体（ER）阴性、更强的增殖性——导致AAW的死亡率比CW合并乳腺癌高出近50%。BP1也可能参与上皮向间充质转化（EMT）的过程，该过程与恶性上皮细胞向间充质细胞的转分化有关。BP1上调EMT诱导剂Twist基因。EMT在乳腺癌的进展、侵袭、转移和耐药过程中发挥重要作用，成为潜在的治疗靶点。临床研究表明，EMT可以预测许多肿瘤的不良预后。综上所述，这些数据表明，在AAW肿瘤中，EMT可能比CW更常见：BP1的表达可能激活Twist，导致EMT，而其他基因可能单独诱导EMT，导致AAW肿瘤更具侵袭性。假设。我们假设：(a) AAW的乳腺肿瘤比CW的肿瘤更容易发生EMT， (b) BP1的高水平表达与EMT有关。具体的目标。目的1。目的：探讨急性肝细胞癌和急性肝细胞癌的EMT发生频率。目标2。确定BP1与EMT的关系。的方法。将在50个来自AAW的肿瘤组织和50个来自CW的肿瘤组织中检测EMT标志物，这些组织与乳腺癌的年龄和分期相匹配。免疫组织化学将用于确定EMT标记物的表达，包括E-cadherin， vimentin和Twist。数据将与所有患者可用的临床病理数据相关联。同样的标记物将在来自肿瘤的一个子集的RNA中测量，该子集的组织是可用的。为了发现BP1在EMT中的作用，上述组织和RNA样本也将被评估BP1水平。我们将研究来自AAW和CW肿瘤的乳腺癌细胞系，以确定BP1和EMT标志物的水平。选择表达低水平或高水平BP1的细胞系分别用于(i)过表达BP1或（ii）抑制BP1，然后测量E-cadherin， vimentin和Twist水平。微阵列将用于鉴定与BP1和EMT相关的基因表达的其他变化。其他检测将包括测量入侵和迁移，以及观察pBP1过表达或减少后的形态学变化。的意义。如果EMT在AAW肿瘤中比在CW肿瘤中更普遍，那么在转移过程中表达的基因将成为很好的治疗靶点，有可能减少或防止转移。如果BP1是EMT的调节因子（通过Twist），那么使用小分子抑制剂、siBP1或其他方法靶向BP1将是一个强有力的理由。

DESCRIPTION (provided by applicant): Our laboratory has discovered a gene, BP1, that is activated in 89% of the tumors of African American women (AAW), compared with 57% of the tumors of Caucasian women (CW). High level BP1 expression is associated with aggressive and larger tumors. Tumors of AAW are also aggressive - higher grade, larger, more frequently estrogen receptor (ER) negative, and more proliferative - resulting in an almost 50% higher mortality rate of AAW than CW with breast cancer. BP1 may also be involved in a process called the epithelial to mesenchymal transition (EMT), which is associated with transdifferentiation of malignant epithelial cells to mesenchymal cells. BP1 up-regulates the Twist gene, an inducer of EMT. EMT plays a role in breast cancer progression, invasion, metastasis, and drug resistance, making it a potential therapeutic target. Clinical studies indicate that EMT is predictive of poor outcome in many tumors. Together, these data suggest that EMT may be more frequent in tumors of AAW than CW: expression of BP1 may activate Twist, causing EMT and, independently, other genes may induce EMT, resulting in the more aggressive tumors seen in AAW. HYPOTHESES. We hypothesize that: (a) the breast tumors of AAW undergo EMT more frequently than tumors of CW, and (b) high level BP1 expression is associated with EMT. SPECIFIC AIMS. Aim 1. To determine the frequency of EMT in the tumors of AAW and CW. Aim 2. To determine the involvement of BP1 in EMT. APPROACH. Markers of EMT will be examined in 50 tumor tissues from AAW and 50 tumor tissues from CW, matched for age and stage of breast cancer. Immunohistochemistry will be used to determine the expression of EMT markers, including E-cadherin, vimentin, and Twist. Data will be correlated with clinico- pathological data available for all patients. The same markers will be measured in RNA from a subset of the tumors for which tissue is available. To discover the involvement of BP1 in EMT, the tissues and RNA samples described above will also be assessed for BP1 levels. Breast cancer cell lines derived from the tumors of AAW and CW will be studied to determine the levels of BP1 and markers of EMT. Selected cell lines expressing either low or high levels of BP1 will be used to (i) overexpress BP1 or (ii) repress BP1, respectively, followed by measurement of E-cadherin, vimentin and Twist levels. Microarrays will be used to identify additional changes in gene expression associated with BP1 and EMT. Additional assays will include measurement of invasion and migration, and observation of morphological changes after overexpression or reduction of pBP1. SIGNIFICANCE. If EMT is more prevalent in tumors of AAW than CW, genes expressed during the transition would make good targets for therapy, with the possibility of reducing or preventing metastases. If BP1 is a regulator of EMT (through Twist), there would be a strong rationale for targeting BP1 using small molecule inhibitors, siBP1 or other approaches. PUBLIC HEALTH RELEVANCE: If EMT is more prevalent in tumors of AAW than CW, genes expressed during the transition would make good targets for therapy, with the possibility of reducing or preventing metastases. If BP1 is a regulator of EMT (through Twist), there would be a strong rationale for targeting BP1 using small molecule inhibitors, siBP1 or other approaches.