Overcoming MITF-conferred drug resistance through dual AURKA/MAPK targeting in human melanoma cells

Abstract

MITF (microphthalmia-associated transcription factor) is a frequently amplified lineage-specific oncogene in human melanoma, whose role in intrinsic drug resistance has not been systematically investigated. Utilizing chemical inhibitors for major signaling pathways/cellular processes, we witness MITF as an elicitor of intrinsic drug resistance. To search kinase(s) targets able to bypass MITF-conferred drug resistance, we employed a multi-kinase inhibitor-directed chemical proteomics-based differential affinity screen in human melanocytes carrying ectopic MITF overexpression. A subsequent methodical interrogation informed mitotic Ser/Thr kinase Aurora Kinase A (AURKA) as a crucial regulator of melanoma cell proliferation and migration, independent of the underlying molecular alterations, including TP53 functional status and MITF levels. Crucially, assessing the efficacy of investigational AURKA inhibitor MLN8237, we pre-emptively witness the procurement of a molecular program consistent with acquired drug resistance. This involved induction of multiple MAPK (mitogen-activated protein kinase) signaling pathway components and their downstream proliferation effectors (Cyclin D1 and c-JUN) and apoptotic regulators (MITF and Bcl-2). A concomitant AURKA/BRAF and AURKA/MEK targeting overcame MAPK signaling activation-associated resistance signature in BRAF- and NRAS-mutated melanomas, respectively, and elicited heightened anti-proliferative activity and apoptotic cell death. These findings reveal a previously unreported MAPK signaling-mediated mechanism of immediate resistance to AURKA inhibitors. These findings could bear significant implications for the application and the success of anti-AURKA approaches that have already entered phase-II clinical trials for human melanoma.

AURKA Overexpression Is Driven by FOXM1 and MAPK/ERK Activation in Melanoma Cells Harboring BRAF or NRAS Mutations: Impact on Melanoma Prognosis and Therapy

“…Accordingly, Vilgelm et al (2015) have shown that combined MDM2 and AURKA inhibition prolongs p53 activation and results in proliferation arrest, increased apoptosis, and immune clearance of melanoma cells. A promising therapeutic approach is the dual targeting of AURKA and MAPK inhibitors that leverages antiproliferative and apoptotic activities overcoming microphthalmia-associated transcription factor (MITF)econferred resistance to AURKA inhibitors (Pathria et al, 2016).…”

“…AURKA encodes Aurora kinase A, which is a serine/threonine kinase involved in mitotic spindle formation, centrosome separation, and G2/M phase transition during the cell cycle (D'Assoro et al 2016). Increased AURKA expression has been reported from nevi to primary and metastatic melanoma (Pathria et al, 2016;Wang et al, 2010), and its inhibition impairs cell proliferation and migration (Xie and Meyskens, 2013). Aurora kinase A overexpression is associated with either occurrence of metastasis (Reiter et al, 2006;Weier and Mao, 2013) or with shorter overall survival in nonmelanoma patients (Zhang et al, 2015).…”

Insights into the non-mitotic functions of Aurora kinase A: more than just cell division

“…The association of AURKA inhibitors with microtubule stabilisers (taxanes) showed promising results [138][139][140][141]. The AURKA inhibitor MLN8054 (a precursor of Alisertib) or Alisertib itself, in combination with the BRAF inhibitor GSK2118436 and the MEK inhibitor GSK1120212, was shown to have a supplementary anti-proliferative effect in 2D and 3D in cellulo models of melanoma [142,143]. However, cell proliferation was not totally abolished and a small fraction of actively proliferating cells were retrieved in the dermal stratum of 3D cultures, indicating their resistance to drugs.…”

Molecular Pathways in Melanomagenesis: What We Learned from Next-Generation Sequencing Approaches

“…However, the mechanism of action of MITF is rather complex: low or absent levels of this protein predispose cells to apoptosis; intermediate MITF expression levels promote cell proliferation and survival; high concentration of intracellular MITF proteins induces antiproliferative effects [ 85 ]. An association was reported between MITF overexpression, partially regulated by AurkA, and MAPK pathway activation in controlling melanoma cell proliferation and migration [ 86 ]. MITF amplification was found in 5.0% of CMs, regardless of the BRAF/RAS mutational status (Table 3 ).…”