Division of General Surgery, Department of Surgery, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, United States of America.
PLoS One. 2013 Aug 22;8(8):e71978. doi: 10.1371/journal.pone.0071978. eCollection 2013.
Pancreatic ductal adenocarcinoma (PDAC) is projected to rise to the second leading cause of U.S. cancer-related deaths by 2020. Novel therapeutic targets are desperately needed. MicroRNAs (miRs) are small noncoding RNAs that function by suppressing gene expression and are dysregulated in cancer. miR-21 is overexpressed in PDAC tumor cells (TC) and is associated with decreased survival, chemoresistance and invasion. Dysregulation of miR regulatory networks in PDAC tumor-associated fibroblasts (TAFs) have not been previously described. In this study, we show that miR-21 expression in TAFs promotes TC invasion.
In-situ hybridization for miR-21 was performed on the 153 PDAC patient UCLA tissue microarray and 23 patient-matched lymph node metastases. Stromal and TC histoscores were correlated with clinicopathologic parameters by univariate and multivariate Cox regression. miR-21 positive cells were further characterized by immunofluorescence for mesenchymal/epithelial markers. For in vitro studies, TAFs were isolated from freshly resected human PDAC tumors by the outgrowth method. miR-21 was overexpressed/inhibited in fibroblasts and then co-cultured with GFP-MiaPaCa TCs to assess TC invasion in modified Boyden chambers.
miR-21 was upregulated in TAFs of 78% of tumors, and high miR-21 significantly correlated with decreased overall survival (P = 0.04). Stromal miR-21 expression was also significantly associated with lymph node invasion (P = 0.004), suggesting that it is driving TC spread. Co-immunofluorescence revealed that miR-21 colocalized with peritumoral fibroblasts expressing α-smooth muscle actin. Moreover, expression of miR-21 in primary TAFs correlated with miR-21 in TAFs from patient-matched LN metastases; evidence that PDAC tumor cells induce TAFs to express miR-21. miR-21 expression in TAFs and TCs promotes invasion of TCs and is inhibited with anti-miR-21.
miR-21 expression in PDAC TAFs is associated with decreased overall survival and promotes TC invasion. Anti-miR-21 may represent a novel therapeutic strategy for dual targeting of both tumor and stroma in PDAC.
预计到 2020 年，胰腺癌（PDAC）将成为美国癌症相关死亡的第二大主要原因。目前急需新的治疗靶点。微小 RNA（miRs）是一种通过抑制基因表达起作用的小型非编码 RNA，在癌症中失调。miR-21 在 PDAC 肿瘤细胞（TC）中过度表达，与降低生存率、化疗耐药性和侵袭性有关。PDAC 肿瘤相关成纤维细胞（TAFs）中 miR 调节网络的失调尚未被描述。在这项研究中，我们表明 TAFs 中的 miR-21 表达促进 TC 侵袭。
对 UCLA 组织微阵列的 153 例 PDAC 患者和 23 例患者匹配的淋巴结转移进行 miR-21 的原位杂交。通过单变量和多变量 Cox 回归分析，对间质和 TC 组织学评分与临床病理参数进行相关性分析。用免疫荧光法对间质中 miR-21 阳性细胞进行间充质/上皮标志物的进一步鉴定。为了进行体外研究，通过外生法从新鲜切除的人类 PDAC 肿瘤中分离 TAFs。在纤维母细胞中过表达/抑制 miR-21，然后将其与 GFP-MiaPaCa TC 共培养，以改良 Boyden 室评估 TC 侵袭。
miR-21 在 78%的肿瘤中上调，高 miR-21 与总生存率降低显著相关（P = 0.04）。间质 miR-21 的表达也与淋巴结浸润显著相关（P = 0.004），表明其正在驱动 TC 的扩散。共免疫荧光显示，miR-21 与表达α-平滑肌肌动蛋白的肿瘤周围成纤维细胞共定位。此外，原发 TAFs 中 miR-21 的表达与患者匹配的 LN 转移中 TAFs 中的 miR-21 相关；这表明 PDAC 肿瘤细胞诱导 TAFs 表达 miR-21。PDAC TAFs 和 TCs 中的 miR-21 表达促进 TCs 的侵袭，用抗 miR-21 抑制其表达。
PDAC TAFs 中的 miR-21 表达与总生存率降低有关，并促进 TC 侵袭。抗 miR-21 可能代表一种新的治疗策略，用于双重靶向 PDAC 中的肿瘤和基质。
