Scientists created a new cancer drug that attaches a targeting peptide to a PI3K inhibitor, making it work better against certain tumor cells while causing fewer side effects in mice, but it’s still early‑stage research and not something you can use yourself yet.

Phosphoinositide 3-kinase (PI3K) inhibitors have demonstrated efficacy in cancer therapy; yet, their clinical use is often restricted by off-target toxicity. Peptide-drug conjugates (PDCs) have emerged as a strategy to improve tumor selectivity by targeting receptors overexpressed in malignant cells. Luteinizing hormone-releasing hormone receptors (LHRHR), upregulated in several cancers, present an attractive target for such approaches. In this study, we obtained an LHRHR-targeting peptide IV-6, characterized by high receptor affinity and robust metabolic stability. IV-6 was then conjugated to the PI3K inhibitor buparlisib, forming the target PDC, DiWB-1. In Vitro, DiWB-1 exhibited superior antineoplastic effects against LHRHR-positive MDA-MB-231 cells, with an IC₅₀ of 1.8 μM, compared with 2.4 μM for buparlisib, and demonstrated reduced toxicity in normal cells. In Vivo, DiWB-1 showed considerable tumor-suppressive effects while minimizing systemic toxicity, avoiding the hepatic and renal damage, as well as hyperglycemia, observed with buparlisib treatment. Pharmacokinetic studies further indicated that DiWB-1 had favorable metabolic stability, with a half-life of 5.6 h, slightly exceeding that of triptorelin (4.2 h). These findings suggest that DiWB-1 holds promise as a selective, potent, and long-acting anticancer PDC, warranting further investigation.