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Published on: July 17, 2020
Targeting SHP2 Reverses BRAF Inhibitor Tolerance in Anaplastic Thyroid Carcinoma
Tao Tang1, Jie Zhou2, Li-Xin Zhang2
1The General Surgery, Langzhong Hospital Affiliated to North Sichuan Medical College, Langzhong, 637400, P.R. China.
Background:
To explore the possibility of a combination of dabrafenib and SHP2 inhibitor in the treatment of anaplastic thyroid carcinoma and to provide a new therapeutic strategy for the treatment of anaplastic thyroid cancer.
Methods:
Firstly, a drug resistance model was established, and the expression levels of related RTK were detected by qPCR. Western blot was used to detect the protein expression levels of Akt and MAPK signaling pathways in the control group, single-drug group and two-drug combination group. The gene silencing of SHP2 was achieved by transfection of siRNA and verified by Western blot. CCK8 kit and clone formation assay were used to detect cell proliferation activity. In vivo model of mutant thyroid cancer cells was established by subcutaneous injection of mice and then divided into four groups. Tumor diameter was measured every two days. Immunohistochemistry was used to evaluate the expression of p-ERK, p-AKT and Ki67 in mouse tumors.
Results:
In this study, dabrafenib-resistant ATC cells were first constructed, and the response of RTKs in drugresistant cells was upregulated to activate Akt and MER/ERK pathways. The activation of Akt and MEK/ERK pathways in the combination group was significantly inhibited, and the proliferation ability of tumor cells was significantly reduced compared with Dabrafenib, SHP099 group and DMSO group. To verify that SHP099 was not off-target, we also silenced SHP2 expression by transfection with siRNA and obtained the same results. Finally, by building a mouse drug resistance model, we confirmed that dabrafenib and SHP099 can also play a powerful anti-cancer effect in vivo.
Conclusion:
The SHP2 inhibitor SHP099 can effectively reverse the drug resistance of dabrafenib through inhibiting the reactivated RAS signaling pathway in anaplastic thyroid cancer.The combination of dabrafenib with SHP2 inhibitor has shown significant tumor suppressive effects for dabrafenib-resistant cells and it may be a new therapeutic strategy with longer lasting therapeutic benefits.
Insights
Combining dabrafenib with a SHP2 inhibitor (SHP099) effectively overcomes drug resistance in anaplastic thyroid cancer. This combination therapy shows significant tumor suppression, offering a promising new strategy for treating resistant thyroid cancer.
Area of Science:
- Oncology
- Molecular Biology
- Pharmacology
Background:
- Anaplastic thyroid carcinoma (ATC) often develops resistance to targeted therapies like dabrafenib.
- Reactivation of signaling pathways, such as Akt and MAPK/ERK, contributes to drug resistance in ATC.
- SHP2 plays a crucial role in mediating these resistance pathways.
Purpose of the Study:
- To investigate the efficacy of combining dabrafenib with a SHP2 inhibitor (SHP099) for treating anaplastic thyroid carcinoma.
- To explore a novel therapeutic strategy for overcoming dabrafenib resistance in ATC.
- To elucidate the molecular mechanisms underlying the combination therapy's effects.
Main Methods:
- Established dabrafenib-resistant ATC cell and mouse models.
- Utilized qPCR and Western blot to analyze RTK expression and signaling pathway activation (Akt, MAPK/ERK).
- Employed siRNA to silence SHP2, CCK8 assays, clone formation assays, and immunohistochemistry to assess cell proliferation and in vivo tumor growth.
Main Results:
- Dabrafenib resistance in ATC was associated with upregulated RTK expression and activated Akt/MAPK pathways.
- The combination of dabrafenib and SHP099 significantly inhibited these pathways and reduced tumor cell proliferation.
- In vivo studies confirmed that the combination therapy suppressed tumor growth in a drug-resistant mouse model.
- SHP2 gene silencing mimicked the effects of SHP099, confirming its on-target activity.
Conclusions:
- SHP099, a SHP2 inhibitor, effectively reverses dabrafenib resistance in anaplastic thyroid cancer by inhibiting the reactivated RAS signaling pathway.
- The combination of dabrafenib and SHP099 demonstrates significant tumor suppressive effects in dabrafenib-resistant ATC cells.
- This combination therapy represents a promising new strategy with potential for longer-lasting therapeutic benefits in treating resistant anaplastic thyroid cancer.
