Molecular Mechanisms and Molecular Subtype-Specific Responses to Paclitaxel in Breast Cancer Cells

Area of Science:

• Oncology
• Molecular Biology
• Pharmacology

Background:

• Paclitaxel (PTX) is a key chemotherapeutic agent for breast cancer (BC), primarily acting via microtubule stabilization.
• Its efficacy is linked to cell-cycle disruption and apoptosis induction.
• Understanding PTX's molecular effects across diverse BC subtypes is crucial for optimizing treatment.

Purpose of the Study:

• To investigate the effects of Paclitaxel (PTX) on gene expression in four distinct breast cancer (BC) cell lines.
• To assess PTX's impact on cancer-related pathways, energy metabolism, and drug resistance.
• To evaluate PTX-induced alterations in cell viability, cell-cycle distribution, and apoptosis.

Main Methods:

• Cytotoxicity was assessed using MTT assays to determine PTX IC50 values in BC cell lines and a control cell line.
• Cells were treated with varying PTX concentrations for 24, 48, and 72 hours.
• Gene expression changes were analyzed using RT-qPCR, while cell-cycle and apoptosis were evaluated by flow cytometry.

Main Results:

• PTX treatment reduced cell viability and increased apoptosis in all tested BC cell lines at specific concentrations and time points.
• PTX significantly altered the expression of genes involved in apoptosis, cell-cycle regulation, angiogenesis, EMT, hypoxia, metabolism, telomere maintenance, and therapy resistance.
• Heterogeneous molecular and cellular responses to PTX were observed across the distinct BC cell lines.

Conclusions:

• Paclitaxel (PTX) elicits diverse responses in molecularly distinct breast cancer (BC) cell lines.
• Observed variations in cell viability, apoptosis, and gene expression suggest underlying mechanisms for differential PTX sensitivity.
• Further validation is required to translate these in vitro findings into clinical applications for breast cancer treatment.