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The yin yang of sunitinib: One drug, two doses, and multiple outcomes
1Department of Microbiology and Immunobiology, Max F. Perutz Laboratories, University of Vienna , Vienna, Austria.
Abstract:
Our recent work showed that sunitinib exerts dual effect on cancer cells in different dose ranges. In clinically relevant doses, cancer cells tolerate sunitinb cytotoxicity by upregulating pro-survival MCL-1 and activating mTORC1 signaling. Inhibition of MCL-1 or mTORC1 sensitized cancer cells to sunitinib. Analysis of tissues from patients correlated MCL-1/mTORC1 induction with resistance to sunitinib.
Insights
Sunitinib has a dual effect on cancer cells. In clinical doses, cancer cells upregulate MCL-1 and mTORC1 to resist sunitinib, but inhibiting these pathways sensitizes them to the drug.
Area of Science:
- Oncology
- Molecular Biology
- Cancer Therapeutics
Background:
- Sunitinib is a tyrosine kinase inhibitor used in cancer therapy.
- Cancer cells can develop resistance to chemotherapy drugs.
- MCL-1 and mTORC1 signaling pathways are implicated in cell survival and drug resistance.
Purpose of the Study:
- To investigate the mechanisms by which cancer cells develop resistance to sunitinib.
- To explore the role of MCL-1 and mTORC1 signaling in sunitinib resistance.
- To evaluate the therapeutic potential of combining sunitinib with MCL-1 or mTORC1 inhibitors.
Main Methods:
- In vitro studies using cancer cell lines treated with varying doses of sunitinib.
- Western blot analysis to assess protein expression levels of MCL-1 and components of the mTORC1 pathway.
- Pharmacological inhibition of MCL-1 and mTORC1 signaling.
- Analysis of patient tumor tissues to correlate biomarker expression with clinical response.
Main Results:
- Sunitinib exhibited a dose-dependent effect on cancer cells.
- Clinically relevant doses of sunitinib led to increased expression of pro-survival MCL-1 and activation of mTORC1 signaling.
- Inhibition of MCL-1 or mTORC1 resensitized resistant cancer cells to sunitinib.
- Patient data confirmed a correlation between elevated MCL-1/mTORC1 signaling and resistance to sunitinib.
Conclusions:
- Upregulation of MCL-1 and activation of mTORC1 signaling are key mechanisms of sunitinib resistance in cancer cells.
- Targeting MCL-1 or mTORC1 in combination with sunitinib may overcome drug resistance.
- These findings provide a rationale for clinical trials investigating combination therapies.