Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, Canada.
PLoS One. 2011 Apr 26;6(4):e19309. doi: 10.1371/journal.pone.0019309.
Src and signaling molecules downstream of Src, including signal transducer and activator of transcription 3 (Stat3) and cMyc, have been implicated in the development, maintenance and/or progression of several types of human cancers, including breast cancer. Here we report the ability of siRNA-mediated Src knock-down alone, and simultaneous knock-down of Src and Stat3 and/or cMyc to inhibit the neoplastic phenotype of a highly metastatic human model breast cancer cell line, MDA-MB-435S, a widely used model for breast cancer research.
METHODOLOGY/RESULTS: Src and its downstream signaling partners were specifically targeted and knocked-down using siRNA. Changes in the growth properties of the cultured cancer cells/tumors were documented using assays that included anchorage-dependent and -independent (in soft agar) cell growth, apoptosis, and both primary and metastatic tumor growth in the mouse tumor model. siRNA-mediated Src knock-down alone, and simultaneous knock-down of Src and Stat3 and/or cMyc inhibited the neoplastic phenotype of a highly metastatic human model breast cancer cell line, MDA-MB-435S. This knock-down resulted in reduced growth in monolayer and soft agar cultures, and a reduced ability to form primary tumors in NOD/SCID mice. In addition, direct intra-tumoral injection of siRNAs targeting these signaling molecules resulted in a substantial inhibition of tumor metastases as well as of primary tumor growth. Simultaneous knock-down of Src and Stat3, and/or Myc exhibited the greatest effects resulting in substantial inhibition of primary tumor growth and metastasis.
CONCLUSIONS/SIGNIFICANCE: These findings demonstrate the effectiveness of simultaneous targeting of Src and the downstream signaling partners Stat3 and/or cMyc to inhibit the growth and oncogenic properties of a human cancer cell line. This knowledge may be very useful in the development of future therapeutic approaches involving targeting of specific genes products involved in tumor growth and metastasis.
Src 及其下游信号分子，包括信号转导子和转录激活子 3（Stat3）和 cMyc，已被牵涉到几种类型的人类癌症的发展、维持和/或进展中，包括乳腺癌。在这里，我们报告了单独使用 siRNA 介导的 Src 敲低，以及同时敲低 Src 和 Stat3 和/或 cMyc，以抑制高度转移性人乳腺癌细胞系 MDA-MB-435S 的肿瘤表型的能力，MDA-MB-435S 是乳腺癌研究中广泛使用的模型。
方法/结果：使用 siRNA 特异性靶向和敲低 Src 和其下游信号伙伴。使用包括锚定依赖性和非依赖性（在软琼脂中）细胞生长、凋亡以及在小鼠肿瘤模型中的原发性和转移性肿瘤生长的测定来记录培养的癌细胞/肿瘤的生长特性的变化。单独使用 siRNA 介导的 Src 敲低，以及同时敲低 Src 和 Stat3 和/或 cMyc，抑制了高度转移性人乳腺癌细胞系 MDA-MB-435S 的肿瘤表型。这种敲低导致单层和软琼脂培养物中的生长减少，并且在 NOD/SCID 小鼠中形成原发性肿瘤的能力降低。此外，直接向肿瘤内注射针对这些信号分子的 siRNA 导致肿瘤转移以及原发性肿瘤生长的实质性抑制。同时敲低 Src 和 Stat3 和/或 Myc 表现出最大的效果，导致原发性肿瘤生长和转移的实质性抑制。
结论/意义：这些发现证明了同时靶向 Src 及其下游信号伙伴 Stat3 和/或 cMyc 以抑制人癌细胞系的生长和致癌特性的有效性。这些知识对于开发涉及靶向参与肿瘤生长和转移的特定基因产物的未来治疗方法可能非常有用。
