We have previously demonstrated that Rad6 and β-catenin enhance each other's expression through a positive feedback loop to promote breast cancer development/progression. While β-catenin has been implicated in melanoma pathogenesis, Rad6 function has not been investigated. Here, we examined the relationship between Rad6 and β-catenin in melanoma development and progression. Eighty-eight cutaneous tumors, 30 nevi, 29 primary melanoma, and 29 metastatic melanomas, were immunostained with anti-β-catenin and anti-Rad6 antibodies. Strong expression of Rad6 was observed in only 27% of nevi as compared to 100% of primary and 96% of metastatic melanomas. β-Catenin was strongly expressed in 97% of primary and 93% of metastatic melanomas, and unlike Rad6, in 93% of nevi. None of the tumors expressed nuclear β-catenin. β-Catenin was exclusively localized on the cell membrane of 55% of primary, 62% of metastatic melanomas, and only 10% of nevi. Cytoplasmic β-catenin was detected in 90% of nevi, 17% of primary, and 8% of metastatic melanoma, whereas 28% of primary and 30% of metastatic melanomas exhibited β-catenin at both locations. These data suggest that melanoma development and progression are associated with Rad6 upregulation and membranous redistribution of β-catenin and that β-catenin and Rad6 play independent roles in melanoma development. 1. Introduction The Wnt/β-catenin pathway has been implicated in the development and progression of melanoma and a wide range of cancer types, including colorectal cancer, breast cancer, esophageal carcinoma, and liver cancer [1–3]. Under normal conditions, intracellular β-catenin levels are kept low through a multiprotein system that mediates β-catenin degradation [4]. Increases in expression and binding of certain Wnt ligands to Frizzled receptor or mutations in specific components of the β-catenin degradation assembly deactivate this regulatory mechanism. Consequently, β-catenin accumulates in the cytoplasm and translocates to the nucleus. Nuclear β-catenin stimulates transcription of a large number of TCF/β-catenin responsive genes that include cyclin D1, c-myc [5, 6], and the melanocyte-specific gene, microphthalmia-associated transcription factor MITF-M [7]. Thus, accumulation of nuclear β-catenin as observed in several cancer types is considered a marker of canonical Wnt/β-catenin pathway deregulation and unfavorable prognosis [3, 8]. Previous studies have reported an association between nuclear β-catenin accumulation and melanoma progression and suggested nuclear β-catenin to be a marker of poor prognosis [1, 7].
References
[1]
D. L. Rimm, K. Caca, G. Hu, F. B. Harrison, and E. R. Fearon, “Frequent nuclear/cytoplasmic localization of β-catenin without exon 3 mutations in malignant melanoma,” American Journal of Pathology, vol. 154, no. 2, pp. 325–329, 1999.
[2]
C.-T. Yeh, C.-J. Yao, J.-L. Yan et al., “Apoptotic cell death and inhibition of Wnt/β-catenin signaling pathway in human colon cancer cells by an active fraction (hs7) from taiwanofungus camphoratus,” Evidence-based Complementary and Alternative Medicine, vol. 2011, Article ID 750230, 2011.
[3]
G. Zulehner, M. Mikula, D. Schneller et al., “Nuclear β-catenin induces an early liver progenitor phenotype in hepatocellular carcinoma and promotes tumor recurrence,” American Journal of Pathology, vol. 176, no. 1, pp. 472–481, 2010.
[4]
B. Bellei, A. Pitisci, C. Catricalà, L. Larue, and M. Picardo, “Wnt/β-catenin signaling is stimulated by α-melanocyte-stimulating hormone in melanoma and melanocyte cells: Implication in cell differentiation,” Pigment Cell and Melanoma Research, vol. 24, no. 2, pp. 309–325, 2011.
[5]
L. Larue and V. Delmas, “Secrets to developing Wnt-age melanoma revealed,” Pigment Cell and Melanoma Research, vol. 22, no. 5, pp. 520–521, 2009.
[6]
T. Yaguchi, Y. Goto, K. Kido et al., “Immune suppression and resistance mediated by constitutive activation of Wnt/β-catenin signaling in human melanoma cells,” The Journal of Immunology, vol. 189, no. 5, pp. 2110–2117, 2012.
[7]
H. R. Widlund, M. A. Horstmann, E. Roydon Price et al., “β-Catenin-induced melanoma growth requires the downstream target Microphthalmia-associated transcription factor,” Journal of Cell Biology, vol. 158, no. 6, pp. 1079–1087, 2002.
[8]
S. C. C. Wong, E. S. F. Lo, K. C. Lee, J. K. C. Chan, and W. L. W. Hsiao, “Prognostic and diagnostic significance of β-catenin nuclear Immunostaining in colorectal cancer,” Clinical Cancer Research, vol. 10, no. 4, pp. 1401–1408, 2004.
[9]
T. Kageshita, C. V. Hamby, T. Ishihara, K. Matsumoto, T. Saida, and T. Ono, “Loss of β-catenin expression associated with disease progression in malignant melanoma,” British Journal of Dermatology, vol. 145, no. 2, pp. 210–216, 2001.
[10]
A. Demunter, L. Libbrecht, H. Degreef, C. De Wolf-Peeters, and J. J. Van den Oord, “Loss of membranous expression β-catenin is associated with tumor progression in cutaneous melanoma and rarely caused by exon 3 mutations,” Modern Pathology, vol. 15, no. 4, pp. 454–461, 2002.
[11]
O. M. Lucero, D. W. Dawson, R. T. Moon, and A. J. Chien, “A re-evaluation of the “oncogenic” nature of Wnt/β-catenin signaling in melanoma and other cancers,” Current Oncology Reports, vol. 12, no. 5, pp. 314–318, 2010.
[12]
B. E. G. Rothberg, A. J. Berger, A. M. Molinaro et al., “Melanoma prognostic model using tissue microarrays and genetic algorithms,” Journal of Clinical Oncology, vol. 27, no. 34, pp. 5772–5780, 2009.
[13]
I. Arozarena, H. Bischof, D. Gilby, B. Belloni, R. Dummer, and C. Wellbrock, “In melanoma, beta-catenin is a suppressor of invasion,” Oncogene, vol. 30, no. 45, pp. 4531–4543, 2011.
[14]
A. J. Chien, E. C. Moore, A. S. Lonsdorf et al., “Activated Wnt/β-catenin signaling in melanoma is associated with decreased proliferation in patient tumors and a murine melanoma model,” Proceedings of the National Academy of Sciences of the United States of America, vol. 106, no. 4, pp. 1193–1198, 2009.
[15]
M. P. V. Shekhar, A. Lyakhovich, D. W. Visscher, H. Heng, and N. Kondrat, “Rad6 overexpression induces multinucleation, centrosome amplification, abnormal mitosis, aneuploidy, and transformation,” Cancer Research, vol. 62, no. 7, pp. 2115–2124, 2002.
[16]
M. P. V. Shekhar, B. Gerard, R. J. Pauley, B. O. Williams, and L. Tait, “Rad6B is a positive regulator of β-catenin stabilization,” Cancer Research, vol. 68, no. 6, pp. 1741–1750, 2008.
[17]
M. P. V. Shekhar, L. Tait, and B. Gerard, “Essential role of T-cell factor/β-catenin in regulation of Rad6B: a potential mechanism for Rad6B overexpression in breast cancer cells,” Molecular Cancer Research, vol. 4, no. 10, pp. 729–745, 2006.
[18]
B. Gerard, L. Tait, P. Nangia-Makker, and M. P. V. Shekhar, “Rad6B acts downstream of Wnt signaling to stabilize β-catenin: implications for a novel Wnt/β-catenin target,” Journal of Molecular Signaling, vol. 6, article 6, 2011.
[19]
M. P. V. Shekhar, L. A. Biernat, N. Pernick, L. Tait, J. Abrams, and D. W. Visscher, “Utility of DNA postreplication repair protein Rad6B in neoadjuvant chemotherapy response,” Medical Oncology, vol. 27, no. 2, pp. 466–473, 2010.
[20]
S. Dihlmann and M. Von Knebel Doeberitz, “Wnt/β-catenin-pathway as a molecular target for future anti-cancer therapeutics,” International Journal of Cancer, vol. 113, no. 4, pp. 515–524, 2005.
[21]
G. M. M？landsmo, R. Holm, J. M. Nesland, ？. Fodstad, and V. A. Fl？renes, “Reduced β-catenin expression in the cytoplasm of advanced-stage superficial spreading malignant melanoma,” Clinical Cancer Research, vol. 9, no. 9, pp. 3383–3388, 2003.
[22]
I. M. Bachmann, O. Straume, H. E. Puntervoll, M. B. Kalvenes, and L. A. Akslen, “Importance of P-cadherin, β-catenin, and Wnt5a/Frizzled for progression of melanocytic tumors and prognosis in cutaneous melanoma,” Clinical Cancer Research, vol. 11, no. 24, pp. 8606–8614, 2005.
[23]
M. E. Roth, J. M. Grant-Kels, A. B. Ackerman et al., “The histopathology of dysplastic nevi: continued controversy,” American Journal of Dermatopathology, vol. 13, no. 1, pp. 38–51, 1991.
[24]
A. Lyakhovich and M. P. V. Shekhar, “RAD6B overexpression confers chemoresistance: RAD6 expression during cell cycle and its redistribution to chromatin during DNA damage-induced response,” Oncogene, vol. 23, no. 17, pp. 3097–3106, 2004.
[25]
K. Rosner, D. R. Mehregan, D. Moussai, J. Abrams, G. Tromp, and D. A. Mehregan, “WT1 marker is not sufficient for distinguishing between melanoma and melanocytic nevi,” Journal of Cutaneous Pathology, vol. 36, no. 10, pp. 1077–1082, 2009.
[26]
H. Mineta, K. Miura, S. Takebayashi et al., “Cyclin D1 overexpression correlates with poor prognosis in patients with tongue squamous cell carcinoma,” Oral Oncology, vol. 36, no. 2, pp. 194–198, 2000.
[27]
D. C. Whiteman, W. J. Pavan, and B. C. Bastian, “The melanomas: a synthesis of epidemiological, clinical, histopathological, genetic, and biological aspects, supporting distinct subtypes, causal pathways, and cells of origin,” Pigment Cell and Melanoma Research, vol. 24, no. 5, pp. 879–897, 2011.
[28]
B. Gerard, M. A. Sanders, D. W. Visscher, L. Tait, and M. P. Shekhar, “Lysine 394 is a novel RAD6B-induced ubiquitination site on beta-catenin,” Biochimica et Biophysica Acta, vol. 1823, no. 10, pp. 1686–1696, 2012.
[29]
T. Oyama, Y. Yamada, K. Hata et al., “Further upregulation of β-catenin/Tcf transcription is involved in the development of macroscopic tumors in the colon of mice,” Carcinogenesis, vol. 29, no. 3, pp. 666–672, 2008.
[30]
P. J. Morin, A. B. Sparks, V. Korinek et al., “Activation of β-catenin-Tcf signaling in colon cancer by mutations in β-catenin or APC,” Science, vol. 275, no. 5307, pp. 1787–1790, 1997.
[31]
J. Palacios and C. Gamallo, “Mutations in the β-catenin gene (CTNNB1) in endometrioid ovarian carcinomas,” Cancer Research, vol. 58, no. 7, pp. 1344–1347, 1998.
[32]
T. Sinnberg, M. Menzel, D. Ewerth et al., “β-catenin signaling increases during melanoma progression and promotes tumor cell survival and chemoresistance,” PLoS ONE, vol. 6, no. 8, Article ID e23429, 2011.
[33]
X. Zhang, C. Morrissey, S. Sun et al., “Androgen receptor variants occur frequently in castration resistant prostate cancer metastases,” PLoS ONE, vol. 6, no. 11, Article ID e27970, 2011.
[34]
C. G. J. M. Hilders, I. M. Munoz, Y. Nooyen, and G. J. Fleuren, “Altered HLA expression by metastatic cervical carcinoma cells as a factor in impaired immune surveillance,” Gynecologic Oncology, vol. 57, no. 3, pp. 366–375, 1995.
[35]
D. S. A. Sanders, K. Blessing, G. A. R. Hassan, R. Bruton, J. R. Marsden, and J. Jankowski, “Alterations in cadherin and catenin expression during the biological progression of melanocytic tumours,” Journal of Clinical Pathology, Molecular Pathology, vol. 52, no. 3, pp. 151–157, 1999.
[36]
R. Silye, A. J. Karayiannakis, K. N. Syrigos et al., “E-cadherin/catenin complex in benign and malignant melanocytic lesions.,” The Journal of Pathology, vol. 186, no. 4, pp. 350–355, 1998.
[37]
S. Kuphal and A. K. Bosserhoff, “Phosphorylation of β-catenin results in lack of β-catenin signaling in melanoma,” International Journal of Oncology, vol. 39, no. 1, pp. 235–243, 2011.
[38]
G. De Panfilis, D. Ferrari, S. Santoro et al., “Cytoplasmic β-catenin is lacking in a subset of melanoma-associated naevi, but is detectable in naevus-associated melanomas: potential implications for melanoma tumorigenesis?” British Journal of Dermatology, vol. 160, no. 3, pp. 600–608, 2009.
[39]
N. Pe？ina-Slaus, M. Zigmund, V. Kusec, T. N. Marti？, M. Caci？, and M. Slaus, “E-cadherin and β-catenin expression patterns in malignant melanoma assessed by image analysis,” Journal of Cutaneous Pathology, vol. 34, no. 3, pp. 239–246, 2007.
[40]
S. Kuphal, I. Poser, C. Jobin, C. Hellerbrand, and A. K. Bosserhoff, “Loss of E-cadherin leads to upregulation of NFκB activity in malignant melanoma,” Oncogene, vol. 23, no. 52, pp. 8509–8519, 2004.
[41]
P. Bernard, A. Fleming, A. Lacombe, V. R. Harley, and E. Vilain, “Wnt4 inhibits β-catenin/TCF signalling by redirecting β-catenin to the cell membrane,” Biology of the Cell, vol. 100, no. 3, pp. 167–177, 2008.
[42]
P. Kavakebi, B. Hausott, A. Tomasino, S. Ingorokva, and L. Klimaschewski, “The N-end rule ubiquitin-conjugating enzyme, HR6B, is up-regulated by nerve growth factor and required for neurite outgrowth,” Molecular and Cellular Neuroscience, vol. 29, no. 4, pp. 559–568, 2005.
