# Drivers of MAPK-redundant resistance to BRAF inhibition in melanoma

> **NIH NIH F30** · UNIVERSITY OF IOWA · 2022 · $43,600

## Abstract

PROJECT SUMMARY
Cutaneous melanoma is an aggressive form of skin cancer. In the US alone, approximately 90,000 new cases
and 9,000 deaths due to melanoma were reported in 2017. Selective inhibitors of BRAFV600E/K work potently
against melanomas driven by oncogenic BRAF. Unfortunately, drug resistance is ubiquitous, and most patients
will progress within two years of therapy. Large-scale genome- and transcriptome- profiling reveal that resistance
to MAPK inhibition (MAPKi) is either MAPK- dependent or redundant. MAPK-dependent (resistance ~50%)
resistance is characterized by the reactivation of MAPK typically through mutations that augment MAPK
signaling. These MAPKi-resistant melanomas are nearly identical at the transcriptome level to their respective
parental cancers, which further support these cancers simply restore MAPK. By contrast, MAPK-redundant
resistance (remaining 50%) is characterized by extensive transcriptional reprogramming and is often devoid of
recurrent mutations. Mechanistically, MAPK-dependent resistance is centered on the formation of Raf homo- or
heter- dimers that are resistant to current generation Raf inhibitors but sensitive to next-generation Raf inhibitors
that have dimer activity. However, MAPK-redundant resistance is not uniform, not well-understood, and lacks a
common therapeutic target. This knowledge is important as there are no current treatment options for
melanomas with MAPK-redundant resistance.
 To address this critical gap, we performed a forward genetic screen to identify novel mechanisms that
drive resistance to MAPKi. This screen was performed using our well-established Sleeping Beauty Transposon
system. The outcome of this screen was that SFKs and PDGFRβ were the preferred MAPK-redundant
mechanisms of resistance for BRAFV600E melanomas A375 and SKMEL28. However the precise mechanisms by
which SFKs and PDGFRβ drive MAPK-redundant resistance are unknown. In Aim 1, I will elucidate the
mechanism of SFKs- and PDGFRβ- driven resistance to MAPKi by testing the hypothesis that actin remodeling
is central to MAPKi resistance that is driven by both SFKs or PDGFRβ and that integrins are critical upstream of
the SFKs resistance program and Akt is a critical downstream meditator of the PDGFR resistance program. In
Aim 2 I will test the hypothesis that SFKs and PDGFRβ promotes MAPKi resistance by activating the
Yap/Taz/TEAD/AP-1 transcriptional complex. The central hypothesis is that actin remodeling and the
YAP/TAZ/AP-1 complex are critical mediators of the SFKs- and PDGFRβ- resistance programs.

## Key facts

- **NIH application ID:** 10302290
- **Project number:** 5F30CA247102-03
- **Recipient organization:** UNIVERSITY OF IOWA
- **Principal Investigator:** Eliot Zhu
- **Activity code:** F30 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $43,600
- **Award type:** 5
- **Project period:** 2019-12-01 → 2023-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10302290

## Citation

> US National Institutes of Health, RePORTER application 10302290, Drivers of MAPK-redundant resistance to BRAF inhibition in melanoma (5F30CA247102-03). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10302290. Licensed CC0.

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