Regulation of miRNA expression in breast cancer cells

描述（由申请人提供）：选择性雌激素受体调节剂（SERM）他莫昔芬（TAM）是最广泛用于治疗和预防雌激素受体α (er α)阳性乳腺癌的内分泌疗法。然而，通过辅助治疗，最初对tam敏感的肿瘤变成了tam耐药。这种获得性TAM耐药的机制尚不清楚，TAM反应的生物标志物可能有助于监测临床反应。MicroRNAs （miRNAs）是一类天然存在的小的非编码RNA分子，与小干扰RNA （sirna）相关，但又不同。mirna参与调控mRNA的翻译和加工，通常通过结合靶mRNA的3'非翻译区，靶向待降解的mRNA转录物。人类基因组被认为含有100 400个mirna。最近，miRNA的异常表达模式与人类乳腺癌有关，一项研究表明，miRNA的差异表达与其他已知的乳腺癌分期和患者预后标志物一致，包括er - α和孕激素受体的表达、肿瘤分期、阳性淋巴结数量和血管侵袭。然而，到目前为止，还没有人研究雌二醇（E2）或选择性内质网调节剂/抗雌激素是否会影响人类乳腺癌中miRNA的表达模式，或者miRNA的表达模式是否与获得性抗雌激素抵抗相关。特异性目的1是鉴定抗雌激素敏感MCF-7乳腺癌细胞中受雌二醇（E2）和4-羟他莫昔芬（4-OHT）调控的mirna。目的1验证E2和4-OHT在人乳腺癌细胞中调控mirna表达差异的假设。此外，我们认为这些mirna反过来调节编码参与分化和细胞增殖的蛋白质的基因的mRNA稳定性。特异性Aim 2验证了miRNA表达在抗雌激素/ tam耐药与敏感乳腺癌细胞中失调的假设。特异性目的3是确定乳腺癌细胞系中e2调控和4- oht调控的mirna是否在人类乳腺肿瘤中表现出异常表达，并与患者对他莫昔芬治疗的反应相关。我们的长期希望是，mirna可能提供新的生物标志物，并为乳腺肿瘤获得TAM/抗雌激素抵抗并成为侵袭性和转移性的机制提供新的见解。

DESCRIPTION (provided by applicant): The selective estrogen receptor modulator (SERM) tamoxifen (TAM) is the most widely used endocrine therapy for the treatment and prevention of estrogen receptor alpha (ERalpha) positive breast cancer. With adjuvant therapy, however, initially TAM-sensitive tumors become TAM-resistant. The mechanism behind such acquired TAM resistance is unknown and biomarkers of TAM-response may be useful to monitor clinical response. MicroRNAs (miRNAs) are a class of naturally-occurring, small, non-coding RNA molecules that are related to, but distinct from, small interfering RNAs (siRNAs). miRNAs are involved in regulating the translation and processing of mRNAs, usually by binding to the 3' untranslated region of target mRNAs and targeting the mRNA transcript to be degraded. The human genome is thought to contain > 400 miRNAs. Abberant patterns of miRNA expression have been recently implicated in human breast cancer and one study showed that miRNAs were differentially expressed in concordance with other well-established markers of breast cancer stage and patient prognosis including ERalpha and progesterone receptor expression, tumor stage, number of positive lymph nodes, and vascular invasion. However, to date, no one has examined whether estradiol (E2) or selective ER modulators/antiestrogens affect the pattern of miRNA expression in human breast cancer or whether miRNA expression patterns correlate with acquired antiestrogen-resistance. Specific Aim 1 is to identify miRNAs that are regulated by estradiol (E2) and 4-hydroxytamoxifen (4-OHT) in antiestrogen-sensitive MCF-7 breast cancer cells. Aim 1 tests the hypothesis that E2 and 4-OHT differentially regulate the expression of miRNAs in human breast cancer cells. Further, we suggest these miRNAs in turn regulate the mRNA stability of genes encoding proteins involved in differentiation and cell proliferation. Specific Aim 2 tests the hypothesis that miRNA expression is dysregulated in antiestrogen/TAM-resistant versus -sensitive breast cancer cells. Specific Aim 3 is to determine if the E2-regulated and 4-OHT-regulated miRNAs identified in breast cancer cell lines show aberrant expression in human breast tumors and correlate with patient response to tamoxifen therapy. It is our long term hope that miRNAs may provide novel biomarkers and new insights into the mechanisms by which breast tumors gain TAM/antiestrogen-resistance and become invasive and metastatic.