Researchers Develop Protein-Based Delivery System to Boost Anticancer Drug Solubility by 3,600-Fold

Osaka Metropolitan University researchers use the L-PGDS protein to deliver Paclitaxel, improving drug absorption and tumor suppression in cancer models.

By: AXL Media

Published: Mar 16, 2026, 6:58 AM EDT

Source: Information for this report was sourced from Osaka Metropolitan University.

Overcoming the Solubility Barrier in Drug Discovery

Modern medicine has produced a vast array of potent drug candidates, yet many remain sidelined due to poor water solubility and high molecular weights. These "difficult-to-handle" compounds often struggle to be absorbed by the body, leading to weak therapeutic effects and a tendency to distribute into healthy tissue, causing severe side effects. To address this, a research group led by Professor Takashi Inui at Osaka Metropolitan University has developed a novel drug delivery system (DDS) specifically designed to transport Paclitaxel (PTX), a widely used but poorly soluble anticancer agent.

The L-PGDS "Beta-Barrel" Carrier

The researchers utilized the lipocalin-type prostaglandin D synthase (L-PGDS) enzyme as a transport vehicle. Through advanced docking simulations, the team discovered that Paclitaxel molecules bind primarily via hydrophobic interactions to the upper region of the L-PGDS "β-barrel"—a cup-like protein structure. This binding mechanism effectively shields the drug from the aqueous environment of the body. Solubility testing confirmed that this protein-binding approach increased PTX solubility approximately 3,600-fold compared to standard saline suspensions, effectively solving the primary barrier to the drug's absorption.

Targeted Delivery via CRGDK Peptides

To ensure the drug reached cancerous tissues rather than healthy ones, the team modified the carrier by attaching a specific targeting peptide called CRGDK to its C-terminus. This peptide is designed to seek out and bind to the neuropilin-1 receptor, which is heavily expressed on the surface of many cancer cells. The resulting complex, L-PGDS-CRGDK, acts as a molecular "GPS," guiding the high-weight anticancer drug directly to the tumor site. This dual-action system—improving solubility while providing selective targeting—represents a significant shift in pharmaceutical delivery strategies.