Dissanayake Samudra K, Weeraratna Ashani T
Laboratory of Immunology, National Institutes of Health, National Institute of Aging, Gerontology Research Center, Baltimore, MD, USA.
Methods Mol Biol. 2008;468:157-72. doi: 10.1007/978-1-59745-249-6_12.
Signaling networks play crucial roles in the changes leading to malignancy. In melanoma, increased Wnt5A expression increases melanoma cell motility via activation of protein kinase C (PKC). PKC isoforms comprise a family ofserine/threonine kinases that are involved in the transduction of signals for cell proliferation, differentiation, and metastasis. The important role of PKC in processes leading to carcinogenesis and tumor cell invasion would render PKC a suitable target for cancer therapy, if not for its ubiquitous nature. Thus, targeting pathways leading to PKC activation that are more tumor specific, such as the non-canonical Wnt pathway, may prove to be the key to targeting PKC in cancer. Here we summarize the current understanding of the Wnt/calcium pathway and discuss methods of detecting activated/phosphorylated PKC as a result of Wnt signaling in malignant melanoma. We have shown that overexpression of Wnt5A results in the activation of PKC, while inhibition of Wnt5A via small interfering RNA (siRNA) treatment results in its inactivation. In addition, the use of PKC activators and inhibitors has allowed us to study Wnt5A effects on downstream genes that may prove to be key targets for molecular therapy.
信号网络在导致恶性肿瘤的变化中起着关键作用。在黑色素瘤中，Wnt5A表达增加通过激活蛋白激酶C（PKC）来增加黑色素瘤细胞的运动性。PKC同工型构成了一个丝氨酸/苏氨酸激酶家族，它们参与细胞增殖、分化和转移信号的转导。如果不是因为PKC的普遍存在，PKC在导致致癌作用和肿瘤细胞侵袭的过程中的重要作用将使其成为癌症治疗的合适靶点。因此，靶向导致PKC激活的更具肿瘤特异性的途径，如非经典Wnt途径，可能是在癌症中靶向PKC的关键。在这里，我们总结了目前对Wnt/钙途径的理解，并讨论了检测恶性黑色素瘤中Wnt信号导致的激活/磷酸化PKC的方法。我们已经表明，Wnt5A的过表达导致PKC的激活，而通过小干扰RNA（siRNA）处理抑制Wnt5A则导致其失活。此外，使用PKC激活剂和抑制剂使我们能够研究Wnt5A对下游基因的影响，这些基因可能被证明是分子治疗的关键靶点。
