Abstract
Ras-driven tumorigenesis is assumed to depend on Raf for ERK activation and proliferation; yet, an in vivo requirement for Raf as MEK/ERK activator in this setting has not been demonstrated to date. Here, we show that epidermis-restricted B-Raf ablation restrains the onset and stops the progression of established Ras-driven tumors by limiting MEK/ERK activation and proliferation. Concomitant elimination of B-Raf and Raf-1 enforces the abrupt regression of established tumors owing to the decrease in ERK activation and proliferation caused by B-Raf ablation combined with the ERK-independent increase in Rho-dependent kinase (Rok) signaling and differentiation triggered by Raf-1 inactivation. Thus, B-Raf and Raf-1 have non-redundant functions in Ras-driven tumorigenesis. Of note, Raf kinase inhibitors achieve impressive results in melanomas harboring oncogenic BRAF, but are ineffective against Ras-driven tumors; moreover, therapy-related skin tumors driven by a paradox ERK activation as well as primary and acquired resistance have been reported. Our results suggest that therapies targeting both Raf kinase-dependent and -independent pathways may be effective against a broader range of malignancies and reduce the risks of adverse effects and/or resistance.
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References
Kern F, Niault T, Baccarini M . Ras and Raf pathways in epidermis development and carcinogenesis. Br J Cancer 2011; 104: 229–234.
Khavari TA, Rinn J . Ras/Erk MAPK signaling in epidermal homeostasis and neoplasia. Cell Cycle 2007; 6: 2928–2931.
Oki-Idouchi CE, Lorenzo PS . Transgenic overexpression of RasGRP1 in mouse epidermis results in spontaneous tumors of the skin. Cancer Res 2007; 67: 276–280.
Vitale-Cross L, Amornphimoltham P, Fisher G, Molinolo AA, Gutkind JS . Conditional expression of K-ras in an epithelial compartment that includes the stem cells is sufficient to promote squamous cell carcinogenesis. Cancer Res 2004; 64: 8804–8807.
Sibilia M, Fleischmann A, Behrens A, Stingl L, Carroll J, Watt FM et al. The EGF receptor provides an essential survival signal for SOS- dependent skin tumor development. Cell 2000; 102: 211–220.
Wang Z, Pedersen E, Basse A, Lefever T, Peyrollier K, Kapoor S et al. Rac1 is crucial for Ras-dependent skin tumor formation by controlling Pak1-Mek-Erk hyperactivation and hyperproliferation in vivo. Oncogene 2010.
Murayama K, Kimura T, Tarutani M, Tomooka M, Hayashi R, Okabe M et al. Akt activation induces epidermal hyperplasia and proliferation of epidermal progenitors. Oncogene 2007; 26: 4882–4888.
Malliri A, van der Kammen RA, Clark K, van der Valk M, Michiels F, Collard JG . Mice deficient in the Rac activator Tiam1 are resistant to Ras-induced skin tumours. Nature 2002; 417: 867–871.
Gupta S, Ramjaun AR, Haiko P, Wang Y, Warne PH, Nicke B et al. Binding of ras to phosphoinositide 3-kinase p110alpha is required for ras-driven tumorigenesis in mice. Cell 2007; 129: 957–968.
Gonzalez-Garcia A, Pritchard CA, Paterson HF, Mavria G, Stamp G, Marshall CJ . RalGDS is required for tumor formation in a model of skin carcinogenesis. Cancer Cell 2005; 7: 219–226.
Galabova-Kovacs G, Matzen D, Piazzolla D, Meissl K, Plyushch T, Chen AP et al. Essential role of B-Raf in ERK activation during extraembryonic development. Proc Natl Acad Sci USA. 2006; 103: 1325–1330.
Ehrenreiter K, Piazzolla D, Velamoor V, Sobczak I, Small JV, Takeda J et al. Raf-1 regulates Rho signaling and cell migration. J Cell Biol 2005; 168: 955–964.
Scholl FA, Dumesic PA, Barragan DI, Harada K, Bissonauth V, Charron J et al. Mek1/2 MAPK kinases are essential for Mammalian development, homeostasis, and Raf-induced hyperplasia. Dev Cell 2007; 12: 615–629.
Dumesic PA, Scholl FA, Barragan DI, Khavari PA, Erk1/2 MAP . kinases are required for epidermal G2/M progression. J Cell Biol 2009; 185: 409–422.
Scholl FA, Dumesic PA, Barragan DI, Charron J, Khavari PA . Mek1/2 gene dosage determines tissue response to oncogenic Ras signaling in the skin. Oncogene 2009; 28: 1485–1495.
Scholl FA, Dumesic PA, Barragan DI, Harada K, Charron J, Khavari PA . Selective role for Mek1 but not Mek2 in the induction of epidermal neoplasia. Cancer Res 2009; 69: 3772–3778.
Bourcier C, Jacquel A, Hess J, Peyrottes I, Angel P, Hofman P et al. p44 mitogen-activated protein kinase (extracellular signal-regulated kinase 1)-dependent signaling contributes to epithelial skin carcinogenesis. Cancer Res 2006; 66: 2700–2707.
Ehrenreiter K, Kern F, Velamoor V, Meissl K, Galabova-Kovacs G, Sibilia M et al. Raf-1 addiction in Ras-induced skin carcinogenesis. Cancer Cell 2009; 16: 149–160.
Riva C, Lavieille JP, Reyt E, Brambilla E, Lunardi J, Brambilla C . Differential c-myc, c-jun, c-raf and p53 expression in squamous cell carcinoma of the head and neck: Implication in drug and radioresistance. Eur J Cancer B Oral Oncol 1995; 31: 384–391.
Wimmer R, Baccarini M . Partner exchange: protein-protein interactions in the Raf pathway. Trends Biochem Sci 2010; 35: 660–668.
Niault TS, Baccarini M . Targets of Raf in tumorigenesis. Carcinogenesis 2010; 31: 1165–1174.
Flaherty KT, Puzanov I, Kim KB, Ribas A, McArthur GA, Sosman JA et al. Inhibition of mutated, activated BRAF in metastatic melanoma. N Engl J Med 2010; 363: 809–819.
Bollag G, Hirth P, Tsai J, Zhang J, Ibrahim PN, Cho H et al. Clinical efficacy of a RAF inhibitor needs broad target blockade in BRAF-mutant melanoma. Nature 2010; 467: 596–599.
Cichowski K, Janne PA . Drug discovery: Inhibitors that activate. Nature 2010; 464: 358–359.
Brower V . BRAF inhibitors: research accelerates in wake of positive findings. J Natl Cancer Inst 2010; 102: 214–215.
Poulikakos PI, Zhang C, Bollag G, Shokat KM, Rosen N . RAF inhibitors transactivate RAF dimers and ERK signalling in cells with wild-type BRAF. Nature 2010; 464: 427–430.
Hatzivassiliou G, Song K, Yen I, Brandhuber BJ, Anderson DJ, Alvarado R et al. RAF inhibitors prime wild-type RAF to activate the MAPK pathway and enhance growth. Nature 2010; 464: 431–435.
Su F, Viros A, Milagre C, Trunzer K, Bollag G, Spleiss O et al. RAS mutations in cutaneous squamous-cell carcinomas in patients treated with BRAF inhibitors. N Engl J Med 2012; 366: 207–215.
Indra AK, Warot X, Brocard J, Bornert JM, Xiao JH, Chambon P et al. Temporally-controlled site-specific mutagenesis in the basal layer of the epidermis: comparison of the recombinase activity of the tamoxifen-inducible Cre-ER(T) and Cre-ER(T2) recombinases. Nucleic Acids Res 1999; 27: 4324–4327.
Ise K, Nakamura K, Nakao K, Shimizu S, Harada H, Ichise T et al. Targeted deletion of the H-ras gene decreases tumor formation in mouse skin carcinogenesis. Oncogene 2000; 19: 2951–2956.
Dajee M, Lazarov M, Zhang JY, Cai T, Green CL, Russell AJ et al. NF-kappaB blockade and oncogenic Ras trigger invasive human epidermal neoplasia. Nature 2003; 421: 639–643.
Quintanilla M, Brown K, Ramsden M, Balmain A . Carcinogen-specific mutation and amplification of Ha-ras during mouse skin carcinogenesis. Nature 1986; 322: 78–80.
Lichtenberger BM, Tan PK, Niederleithner H, Ferrara N, Petzelbauer P, Sibilia M . Autocrine VEGF signaling synergizes with EGFR in tumor cells to promote epithelial cancer development. Cell 2010; 140: 268–279.
Maurer G, Tarkowski B, Baccarini M . Raf kinases in cancer-roles and therapeutic opportunities. Oncogene 2011; 30: 3477–3488.
Lock FE, Hotchin NA . Distinct roles for ROCK1 and ROCK2 in the regulation of keratinocyte differentiation. PLoS ONE 2009; 4: e8190.
McMullan R, Lax S, Robertson VH, Radford DJ, Broad S, Watt FM et al. Keratinocyte differentiation is regulated by the Rho and ROCK signaling pathway. Curr Biol 2003; 13: 2185–2189.
Honma M, Benitah SA, Watt FM . Role of LIM kinases in normal and psoriatic human epidermis. Mol Biol Cell 2006; 17: 1888–1896.
Karreth FA, Frese KK, Denicola GM, Baccarini M, Tuveson DA . C-Raf is required for the initiation of lung cancer by K-Ras. Cancer Discov 2011; 1: 128–136.
Blasco RB, Francoz S, Santamaria D, Canamero M, Dubus P, Charron J et al. c-Raf, but not B-Raf, is essential for development of K-Ras oncogene-driven non-small cell lung carcinoma. Cancer Cell 2011; 19: 652–663.
Ridky TW, Khavari PA . Pathways sufficient to induce epidermal carcinogenesis. Cell Cycle 2004; 3: 621–624.
Solit DB, Rosen N . Resistance to BRAF inhibition in melanomas. N Engl J Med 2011; 364: 772–774.
Downward J . Targeting RAF: trials and tribulations. Nat Med 2011; 17: 286–288.
Montagut C, Sharma SV, Shioda T, McDermott U, Ulman M, Ulkus LE et al. Elevated CRAF as a potential mechanism of acquired resistance to BRAF inhibition in melanoma. Cancer Res 2008; 68: 4853–4861.
Heidorn SJ, Milagre C, Whittaker S, Nourry A, Niculescu-Duvas I, Dhomen N et al. Kinase-dead BRAF and oncogenic RAS cooperate to drive tumor progression through CRAF. Cell 2010; 140: 209–221.
Acknowledgements
We thank Karin Ehrenreiter and the animal house team for excellent technical help, M Sibilia for the K5-SOS-F mice and P Chambon for the K5-Cre-er(T) animals. This work was supported by European Commission grant LSH-CT-2003–506803 and by Austrian Research Fund grant P19530-B11 (to MB).
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Kern, F., Doma, E., Rupp, C. et al. Essential, non-redundant roles of B-Raf and Raf-1 in Ras-driven skin tumorigenesis. Oncogene 32, 2483–2492 (2013). https://doi.org/10.1038/onc.2012.254
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DOI: https://doi.org/10.1038/onc.2012.254
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