# Phosphoinositide-dependent kinase 1 (PDK1) in cancer: molecular insights and therapeutic strategies

## TL;DR

This paper reviews the role of PDK1 in cancer signaling and explores new drug development strategies to target this underused therapeutic hub.

## Contribution

The paper provides updated insights into PDK1's structure and function, and proposes novel therapeutic strategies to overcome its druggability challenges.

## Key findings

- PDK1 is a central regulator of AGC kinases and plays a key role in cancer progression.
- Current drug development faces challenges due to PDK1's conserved ATP-binding site and dynamic structure.
- New approaches like allosteric inhibition and biomarker-based patient selection are being explored.

## Abstract

3-Phosphoinositide-dependent protein kinase 1 (PDK1) has emerged as one of the most strategically positioned and paradoxically underexploited regulators within Pl3K. It is the main controller of the AGC kinase family, which includes AKT, S6K, SGK, and PKC isoforms. PDK1 is a central signaling hub downstream of the PI3K signaling pathway. It controls key cellular processes such as proliferation, metabolism, and survival by orchestrating activation-loop phosphorylation. Aberrant activation of PDK1 facilitates tumor initiation, progression, and therapeutic resistance in various cancer types. Scientists have not been able to develop small-molecule inhibitors that are as selective and work as well in the clinic as they do for other kinases. This is mostly because the ATP-binding site is highly conserved, while PDK1’s structure is very dynamic. This review summarizes recent progress in comprehending PDK1’s structure, regulation, and its function in oncogenic (cancer-promoting) signaling. We discuss medicinal chemistry strategies like ATP-competitive, allosteric, and dual-site inhibition, as well as rational polypharmacology and combination approaches to overcome pathway redundancy. We also discuss how far we have come in identifying biomarkers to help us select patients and monitor their responses. These efforts make PDK1 a promising but underused target for therapy. New opportunities are emerging to use it for diseases beyond cancer, such as inflammatory, metabolic, and neurological diseases.