Semaphorin 3A Suppresses Tumor Growth and Metastasis in Mice Melanoma Model Goutam Chakraborty1¤, Santosh Kumar1., Rosalin Mishra1., Tushar V. Patil2, Gopal C. Kundu 1 * 1 National Center for Cell Science (NCCS), NCCS Complex, Pune, India, 2 Department of Histopathology, YCM Hospital, Pune, India Abstract Background: Recent understanding on cancer therapy indicated that targeting metastatic signature or angiogenic switch could be a promising and rational approach to combat cancer. Advancement in cancer research has demonstrated the potential role of various tumor suppressor proteins in inhibition of cancer progression. Current studies have shown that axonal sprouting inhibitor, semaphorin 3A (Sema 3A) acts as a potent suppressor of tumor angiogenesis in various cancer models. However, the function of Sema 3A in regulation of melanoma progression is not well studied, and yet to be the subject of intense investigation. Methodology/Principal Findings: In this study, using multiple in vitro and in vivo approaches we have demonstrated that Sema 3A acts as a potent tumor suppressor in vitro and in vivo mice (C57BL/6) models. Mouse melanoma (B16F10) cells overexpressed with Sema 3A resulted in significant inhibition of cell motility, invasiveness and proliferation as well as suppression of in vivo tumor growth, angiogenesis and metastasis in mice models. Moreover, we have observed that Sema 3A overexpressed melanoma clone showed increased sensitivity towards curcumin and Dacarbazine, anti-cancer agents. Conclusions: Our results demonstrate, at least in part, the functional approach underlying Sema 3A mediated inhibition of tumorigenesis and angiogenesis and a clear understanding of such a process may facilitate the development of novel therapeutic strategy for the treatment of cancer. Citation: Chakraborty G, Kumar S, Mishra R, Patil TV, Kundu GC (2012) Semaphorin 3A Suppresses Tumor Growth and Metastasis in Mice Melanoma Model. PLoS ONE 7(3): e33633. doi:10.1371/journal.pone.0033633 Editor: Irina V. Lebedeva, Enzo Life Sciences, Inc., United States of America Received October 8, 2011; Accepted February 16, 2012; Published March 20, 2012 Copyright: 2012 Chakraborty et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: The fellowships of G.C. and R.M. were supported by the Council of Scientific and Industrial Research, Government of India, and the fellowship of S.K. was supported by the University Grant Commission, Government of India. The cost of the reagents/consumables was supported by the NCCS Core fund. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. * E-mail: kundu@nccs.res.in . These authors contributed equally to this work. ¤ Current address: Cell Biology Division, Sloan-Kettering Institute, Memorial Sloan-Kettering, New York, New York, United States of America Introduction Melanoma or malignancies of melanocytic tissues have been identified as one of the most malignant cancer in the United States and around the world. In the year 2010, more than 68,130 new cases of melanoma have been reported in the United States with a result of 8,700 deaths [1]. Malignant progression of cancer cells depends on intrinsic crosstalk between several factors, overexpres- sion of various oncogenic molecules and loss of function of tumor suppressor genes. Therefore, understanding the mechanisms of various tumor suppressor genes in regulation of cancer progression and their possible role in cancer therapeutics is under intense investigation. Semaphorins have been originally known as a large family of evolutionary conserved axonal guidance molecules [2,3]. The role of semaphorins in various physiological as well as pathophysiological processes including cell migration, regulation of immune response, angiogenesis and cancer have recently been studied [4]. Among various semaphorins, selected members of semaphorin 3 (Sema 3) family are involved in suppression of tumor progression and have been considered as potent tumor suppressors [5]. Loss of expressions of Sema 3B and Sema 3F gene (deletion of chromosome 3p21.3 in human) have been shown to associate with lung cancer progression [6–8]. On the other hand, overexpression of these molecules inhibits tumor cell proliferation and in vivo tumor growth [9–12]. Moreover, Semaphorin 3A (Sema 3A), another member of this family is shown to inhibit angiogenesis and acts as tumor suppressor [13–16]. Sema 3A is originally described as a secretory protein with potent axonal repulsive activity [17,18]. Polleux et al have identified the chemoattractive effect of Sema 3A on cortical apical dendrites [19] and shown that Sema 3A acts as a crucial regulatory molecule for neuronal development. However, Serini et al have observed a significant vascular defect in Sema 3A mice [16]. In this study, we have deciphered the function of Sema 3A beyond brain, and demonstrated that this protein could play an important role in melanoma growth. Knockdown of endogenous Sema 3A significantly induce in vitro migration of human breast cancer cell and indicated that Sema 3A may act as a potent tumor suppressor [20]. Overexpression of Sema 3A attenuates invasion and matrigel adhesion of human prostate cancer cells [21]. Moreover, loss of Sema 3A inhibitory loop in hormone-refractory human prostatic cancer has been recently identified by tissue microarray analysis PLoS ONE | www.plosone.org 1 March 2012 | Volume 7 | Issue 3 | e33633