# ΔNp63α drives serine synthesis to promote carboplatin resistance in NSCLC

## TL;DR

A protein called ΔNp63α helps lung cancer cells resist chemotherapy by boosting serine production, suggesting new treatment strategies.

## Contribution

Identifies ΔNp63α as a master regulator of serine biosynthesis that promotes carboplatin resistance in LUSC.

## Key findings

- Overexpression of serine synthesis enzymes correlates with poor prognosis in lung cancer.
- ΔNp63α directly activates serine biosynthesis genes to enhance antioxidant defense and DNA repair.
- Blocking serine synthesis and intake overcomes chemotherapy resistance in ΔNp63α-driven LUSC.

## Abstract

Serine metabolism is a critical vulnerability in cancer; however, its role in mediating therapeutic resistance in non-small cell lung cancer (NSCLC) remains incompletely understood. In this study, we identify key enzymes in the serine synthesis pathway (SSP), namely PHGDH, PSAT1 and PSPH, as well as the serine transporter SLC1A4, which are significantly overexpressed in lung cancer and correlate with poor patient prognosis. We show that serine contributes to carboplatin resistance in NSCLC, particularly in lung squamous cell carcinoma (LUSC). Notably, the LUSC lineage-specific oncogene ΔNp63α serves as a master transcriptional regulator of serine biosynthesis, directly transactivating the expression of PHGDH, PSAT1, PSPH, and SLC1A4. ΔNp63α-driven serine biosynthesis supports nucleotide synthesis and enhances antioxidant defense, enabling cancer cells to survive carboplatin-induced DNA damage and oxidative stress, thereby promoting therapeutic resistance. The combined inhibition of endogenous serine synthesis and restriction of exogenous serine/glycine significantly overcomes ΔNp63α-mediated carboplatin resistance. Our findings establish the ΔNp63α-SSP axis as a critical mechanism driving carboplatin resistance in LUSC. These results highlight dual-targeted disruption of serine availability as a promising therapeutic strategy to overcome chemotherapy resistance in ΔNp63α-driven LUSC. This study underscores the importance of lineage-specific metabolic dependencies as essential targets for precision oncology in NSCLC.