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Study breakdown

Combining GHRH Antagonist Peptides With PI3K Inhibitors Kills More Prostate Cancer Cells

In VitroLow evidence
The takeaway

GHRH antagonist peptides combined with PI3K inhibitors significantly enhanced cell death across all prostate cancer types, including androgen-resistant cancers.

All prostate cancer types responded

GHRH antagonist plus PI3K inhibitor combination killed cells across all prostate cancer subtypes including androgen-resistant disease

What the researchers found

PI3Kα and PI3Kβ inhibitors consistently increased cell death when combined with GHRH antagonist peptides MIA-602/690 across all prostate cancer types including androgen-resistant disease.

Why it matters

Advanced prostate cancer resistant to hormone therapy has limited treatment options. This peptide-drug combination could provide a new therapeutic strategy for these difficult-to-treat cancers.

The numbers in context

MIA-602/690 decreased androgen receptors and likely enhanced PI3K (negative feedback). Adding PI3K alpha or beta inhibitors countered this. Affected apoptosis (Mcl-1L to Mcl-1S switch), proliferation (E2F1, cyclin A), AKT, and ERK.

How the study worked

In vitro drug combination screening testing GHRH antagonists (MIA-602, MIA-690) with PI3K isoform inhibitors against multiple prostate cancer cell lines.

Who was studied

Prostate cancer cell lines

What this study cannot tell us

In vitro cell line study — drug combinations effective in culture may not translate to clinical efficacy. Dosing, timing, and toxicity in living organisms need to be assessed.

How to read the evidence

In vitro combination study — demonstrates drug synergy in cell cultures but requires in vivo validation before clinical translation.

When this study was published

Published in 2025, advancing peptide-based combination strategies for prostate cancer.

The bigger picture

Combining peptide therapies with targeted small molecule drugs is an emerging strategy in oncology that could overcome single-agent limitations and resistance mechanisms.

Questions still open

  • What is the mechanism of synergy between GHRH antagonists and PI3K inhibitors?
  • Would this combination work in prostate cancer animal models and eventually in patients?

Common questions

What are GHRH antagonists?
GHRH antagonist peptides block growth hormone-releasing hormone signaling, which many cancers use to fuel their growth. While they show anticancer activity alone, they work better when combined with other drugs.
Why is androgen-resistant prostate cancer so hard to treat?
Most prostate cancers initially respond to hormone therapy, but many eventually become resistant. These resistant cancers have limited treatment options, making new combination strategies like GHRH antagonists plus PI3K inhibitors important to explore.

Read the original research

Growth Hormone-Releasing Hormone (GHRH) Antagonist Peptides Combined with PI3K Isoform Inhibitors Enhance Cell Death in Prostate Cancer.

Cancers, 17(10)

Citation

Perez-Stable, Carlos; de Las Pozas, Alicia; Wangpaichitr, Medhi; Sha, Wei; Wang, Haibo; Cai, Renzhi; Schally, Andrew V. (2025). Growth Hormone-Releasing Hormone (GHRH) Antagonist Peptides Combined with PI3K Isoform Inhibitors Enhance Cell Death in Prostate Cancer.. Cancers, 17(10). https://doi.org/10.3390/cancers17101643