TGFβ signaling sensitizes MEKi-resistant human melanoma to targeted therapy-induced apoptosis

Area of Science:

• Oncology
• Molecular Biology
• Cell Signaling

Background:

• The TGFβ signaling pathway has diverse roles, promoting melanoma invasion and metastasis.
• Its role in melanoma therapy response is controversial, with conflicting reports on resistance versus enhanced cell death.
• The dose-dependent effects of TGFβ signaling in melanoma treatment remain unclear.

Purpose of the Study:

• To investigate the dose-dependent effect of TGFβ signaling on melanoma response to targeted therapy.
• To elucidate the molecular mechanisms by which TGFβ signaling influences therapeutic outcomes.
• To explore the potential of combined TGFβ activation and MAPK inhibition as a therapeutic strategy.

Main Methods:

• Transcriptomic analyses to identify gene expression changes.
• Genomic target identification of SMAD4, a key TGFβ effector.
• Functional validation of apoptosis-related genes, including BCL2L11 (BIM).
• In vitro studies using melanoma cell lines and in vivo studies with synthetic TGFB1 mRNA.

Main Results:

• High doses of TGFβ signaling, combined with MAPK pathway inhibition, induce apoptosis in targeted therapy-resistant melanoma cells.
• TGFβ signaling activation switches target gene expression from pro-invasive to pro-apoptotic functions.
• A novel apoptosis-inducing gene signature was identified, with BCL2L11 (BIM) playing a crucial role.

Conclusions:

• TGFβ signaling's outcome in melanoma targeted therapy is dose-dependent.
• High-dose TGFβ activation synergizes with MAPK inhibition to promote apoptosis via a specific gene signature.
• Targeted activation of TGFβ signaling, potentially via synthetic mRNA, offers a promising therapeutic avenue for melanoma.