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Synergistic targeting of the PI3K/mTOR and MAPK/ERK pathways in Merkel cell carcinoma

Arturo Temblador1, Dimitrios Topalis1, Graciela Andrei1

  • 1Rega Institute for Medical Research, Department of Microbiology, Immunology and Transplantation, Laboratory of Virology and Chemotherapy, KU Leuven, 3000, Leuven, Belgium.

Tumour Virus Research
|August 25, 2022
PubMed

Insights

Combining MLN0128, an mTOR inhibitor, with trametinib, a MEK inhibitor, shows synergistic effects in Merkel cell carcinoma (MCC) treatment. This combination therapy offers a promising strategy to improve MCC management and overcome resistance to single-agent treatments.

Area of Science:

  • Oncology
  • Dermatology
  • Molecular Biology

Background:

  • Merkel cell carcinoma (MCC) is an aggressive skin cancer linked to Merkel cell polyomavirus (MCPyV) or UV mutations.
  • Current treatments like immune-checkpoint inhibitors have limited efficacy, necessitating novel therapeutic strategies.
  • The PI3K/mTOR and MAPK/ERK pathways are frequently dysregulated in cancer, presenting therapeutic targets.

Purpose of the Study:

  • To investigate the synergistic potential of combining MLN0128 (a dual mTOR1/2 inhibitor) with trametinib (a MEK1/2 inhibitor) in MCC.
  • To evaluate the impact of this combination therapy on MCC cell lines and xenografts.
  • To explore a new therapeutic approach for MCC to overcome drug resistance and toxicity.

Main Methods:

  • Utilized MCC cell lines and xenografts for in vitro and in vivo studies.
  • Administered MLN0128 as a dual mTOR1/2 inhibitor and trametinib as a MEK1/2 inhibitor.
  • Assessed synergistic effects and alterations in downstream signaling pathway proteins.

Main Results:

  • The combination of MLN0128 and trametinib demonstrated synergistic activity in MCC cell lines.
  • Combined targeting led to significant alterations in the protein levels of downstream elements within the PI3K/mTOR and MAPK/ERK pathways.
  • Synergistic effects suggest a potential for reduced individual drug doses, mitigating toxicity and resistance.

Conclusions:

  • The combination of MLN0128 and trametinib is a promising therapeutic strategy for Merkel cell carcinoma.
  • This synergistic approach may improve clinical outcomes by enhancing efficacy and reducing side effects compared to single-agent therapies.
  • Further investigation into this combination therapy could lead to improved treatment protocols for MCC patients.
Keywords:
Combined targetingMerkel cell carcinomaMerkel cell polyomavirusPathway inhibitionSynergism

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