Targeting PI3K in Cancer: Impact on Tumor Cells, Their Protective Stroma, Angiogenesis, and Immunotherapy

Area of Science:

• Oncology
• Immunology
• Molecular Biology

Background:

• The phosphoinositide 3-kinase (PI3K) pathway is frequently hyperactivated in various cancers.
• While PI3K inhibitors show promise, their capacity to directly induce tumor cell death is often limited.
• PI3K inhibition can also disrupt cancer cell communication with stromal signals, as seen with idelalisib in B-cell malignancies.

Purpose of the Study:

• To explore the broader therapeutic potential of PI3K inhibitors beyond direct cancer cell killing.
• To investigate the role of PI3K isoform-selective inhibitors in cancer immunotherapy and anti-angiogenesis.
• To understand how PI3K inhibition impacts the tumor microenvironment and immune responses.

Main Methods:

• Review of existing literature on PI3K pathway signaling in cancer.
• Analysis of the effects of PI3K isoform-specific inhibition (PI3Kδ, PI3Kγ) on immune cells.
• Exploration of PI3K inhibition's impact on tumor angiogenesis and drug delivery.

Main Results:

• PI3K inhibition can impair cancer cell survival and proliferation.
• Targeting leukocyte-enriched PI3K isoforms (PI3Kδ, PI3Kγ) may enhance antitumor T-cell responses by modulating regulatory T cells and myeloid-derived suppressor cells.
• PI3K inhibitors have the potential to target tumor angiogenesis, improving the delivery of therapeutics.

Conclusions:

• PI3K inhibitors offer multifaceted therapeutic strategies by impacting cancer cells, the tumor microenvironment, and immune responses.
• Exploiting PI3K isoform-selective inhibitors in combination with immunotherapy and anti-angiogenesis treatments holds significant promise.
• Future research should focus on the effects of PI3K inhibitors on the tumor stroma to fully leverage their therapeutic potential.