Exploring Prima-1MET as a single agent or in combination with tamoxifen in breast cancer cells in vitro
Ali Haider Alhammer1, Shahad Ali Mudhafar1, Shaimaa Yousif Abdulfattah1
1Medical and Molecular Biotechnology Department, Biotechnology Research Center, Al-Nahrain University, Jadriya, Baghdad, Iraq.
Abstract:
The mutant tumor suppressor p53 (p53-mut) is expressed in approximately 1/3 of breast cancer cases and 2/3 of triple-negative breast cancer (TNBC). It is linked to metastasis and resistance to various cancer therapies. A p53 reactivator, Prima-1MET (or APR-246), has shown potential synergy with certain conventional therapies against cancer cells with various p53 statuses across a range of cancer types. Moreover, the clinical form eprenetapopt is showing promise in clinical trials. Thus, we examined the cytotoxic effects of Prima-1MET against a TNBC-derived p53-mut cell line (MDA-MB231) and an estrogen receptor-positive (ER+) cell line (MCF7) that expresses wild-type p53 (p53-wt), either as a monotherapy or in combination with tamoxifen (Tam). Viability, migration, morphology, apoptosis, and expression of the cell cycle gene CCND1 were detected via standard in vitro methods. With CalcuSyn, the combination index (CI) was calculated to assess synergy. Both MDA-MB231 and MCF7 cells cocultured with Prima-1MET alone exhibited an antiproliferative effect, which was linked to apoptosis and reduced migratory potential. Furthermore, upon exposure to the combination of 10 μM Prima-1MET and 10 μM Tam, synergistic effects were detected, reflected by decreased viability, migration, altered morphology, and induction of apoptosis, along with downregulation of CCND1. Hence, these results emphasize the attractiveness of the combination of Prima-1MET and Tam as a therapeutic approach for TNBC and ER + breast cancer, irrespective of p53 mutational status; therefore, these results encourage further preclinical and clinical studies, considering that the effective dose of Prima-1MET is less than the reported clinically achievable plasma level (∼80 μg/ml).
Insights
Mutant p53 is common in breast cancer. Prima-1MET combined with tamoxifen showed synergistic effects against triple-negative breast cancer (TNBC) and ER+ cells, reducing viability and migration.
Area of Science:
- Oncology
- Molecular Biology
- Pharmacology
Background:
- Mutant tumor suppressor p53 (p53-mut) is prevalent in breast cancer, particularly triple-negative breast cancer (TNBC), and is associated with metastasis and treatment resistance.
- p53 reactivators, such as Prima-1MET (eprenetapopt), show promise in restoring p53 function and exhibit synergistic potential with conventional therapies.
Purpose of the Study:
- To investigate the cytotoxic effects of Prima-1MET, alone and in combination with tamoxifen (Tam), on p53-mut TNBC (MDA-MB231) and wild-type p53 (p53-wt) estrogen receptor-positive (ER+) (MCF7) breast cancer cell lines.
- To evaluate the impact of this combination therapy on cell viability, migration, morphology, apoptosis, and CCND1 gene expression.
Main Methods:
- Standard in vitro assays were used to assess cell viability, migration, morphology, and apoptosis.
- The expression of the cell cycle gene CCND1 was analyzed.
- Synergy was quantified using the combination index (CI) calculated with CalcuSyn software.
Main Results:
- Prima-1MET monotherapy demonstrated antiproliferative effects, inducing apoptosis and reducing migration in both MDA-MB231 and MCF7 cells.
- The combination of 10 μM Prima-1MET and 10 μM Tam exhibited synergistic effects, significantly decreasing cell viability and migration.
- Combined treatment led to altered cell morphology, increased apoptosis, and downregulation of CCND1 expression.
Conclusions:
- The combination of Prima-1MET and tamoxifen presents a promising therapeutic strategy for both TNBC and ER+ breast cancer, regardless of p53 mutational status.
- These findings support further preclinical and clinical investigation of this synergistic combination therapy.
- The effective dose of Prima-1MET used in vitro is below the clinically achievable plasma levels, suggesting therapeutic potential.
