Cross-talk between integrins and oncogenes modulates chemosensitivity

Area of Science:

• Molecular oncology and cancer cell biology
• Integrin signaling and cancer therapeutics

Background:

• Chemotherapy effectiveness often hinges on inducing cancer cell death via DNA damage.
• The p53 tumor suppressor pathway, crucial for DNA damage response, is frequently lost in cancer.
• Cancer cell sensitivity to genotoxic agents is influenced by oncogenic signaling and microenvironment interactions.

Purpose of the Study:

• To investigate how oncogenes modulate cellular responses to genotoxic agents.
• To examine the role of integrin adhesion receptors in mediating chemoresistance or sensitization.
• To understand the interplay between specific oncogenes (c-Src, H-Ras) and integrins (beta1, beta3) in cancer cell death pathways.

Main Methods:

• Utilized epithelial cells with suppressed p53 activity expressing either beta1 or beta3 integrins.
• Treated cells with genotoxic agents like cisplatin.
• Assessed apoptosis, G(2) arrest, endoplasmic reticulum stress, and caspase-3 activation in response to oncogene and integrin expression profiles.

Main Results:

• Cells expressing beta1 integrins and the c-Src[Y530F] oncogene showed enhanced apoptosis upon genotoxic treatment.
• This sensitization was reduced in cells expressing beta3 integrins instead of beta1.
• The H-Ras[G12V] oncogene did not sensitize cells to genotoxicants, irrespective of integrin type.
• c-Src[Y530F]-mediated sensitization involved endoplasmic reticulum stress and caspase-3 activation, independent of p53.

Conclusions:

• Oncogene and integrin expression profiles significantly impact cancer cell response to genotoxic chemotherapy.
• The c-Src oncogene, in conjunction with beta1 integrins, can sensitize cancer cells to chemotherapy through non-p53 pathways.
• These findings suggest that targeting oncogene-integrin interactions could be a strategy to improve chemotherapy efficacy.