Genomic analysis has revealed that approximately 40% of bladder cancer (BLCA) tumors harbor alterations in the PI3K/AKT pathway, with PIK3CA mutations occurring in 15-25% of cases. PIK3CA, which encodes the catalytic p110α subunit of PI3K, plays a critical role in regulating cell survival, proliferation, and metabolism. However, the metabolic and functional consequences of PIK3CA mutations in BLCA remain poorly defined.
To investigate the role of PIK3CA mutations in BLCA, we performed targeted sequencing on tumors from patients, identifying recurrent alterations. Using CRISPR/Cas9 knock-in models in SCaBER and UM-UC-3 cell lines, we introduced the PIK3CA E545K mutation to study its effects. We conducted transcriptomic profiling, targeted metabolomics, and stable isotope tracing to assess metabolic reprogramming. Functional assays measured proliferation, mitochondrial complex I activity, and glutaminolysis. Orthotopic xenografts in mice were used to evaluate in vivo tumor growth and metabolism.
PIK3CA mutations were present in 20% of cases, consistent with TCGA data. The E545K and E545Q hotspots accounted for 70% of these mutations. PIK3CA E545K strongly activated PI3K/AKT signaling. Transcriptomic analysis revealed enrichment of OXPHOS, fatty acid metabolism, and mTORC1 signaling. Metabolomics indicated changes in TCA cycle metabolites and enhanced reductive carboxylation of glutamine to citrate, driving fatty acid synthesis. Mutant cells showed increased expression of GLS1 and FASN, higher proliferation rates, and elevated mitochondrial complex I activity. In vivo, PIK3CA-mutant xenografts displayed significantly increased tumor growth.
PIK3CA mutations are frequent drivers of metabolic reprogramming in BLCA, leading to increased glutamine flux, elevated OXPHOS activity, and enhanced fatty acid synthesis, all of which contribute to tumor progression. These findings provide the first comprehensive evidence that PIK3CA-driven metabolic alterations are both biomarkers of aggressive disease and actionable therapeutic targets. The efficacy of PI3Kα inhibition in combination with metabolic targets may support its potential in precision medicine for PIK3CA-mutant BLCA and highlights the value of integrating metabolic biomarkers into treatment strategies for advanced BLCA.
Cell communication and signaling : CCS. 2026 Jul 14 [Epub ahead of print]
Karthik Reddy Kami Reddy, Vasanta Putluri, Danthasinghe Waduge Badrajee Piyarathna, Jun Hyoung Park, Aaditya Krishna Arun, Sachin B Jorvekar, Yongchao Dou, Mohammed Khurshidul Hassan, Chandra Sekhar Amara, Abu Hena Mostafa Kamal, Chandra Shekar R Ambati, Jun Xu, Daniel Kraushaar, Adriana Langer Gramer, Allison C Bellman, Leomar Y Ballester, Yuan Xu, Robert Taylor Ripley, Seth P Lerner, Roni J Bollag, Martha K Terris, Chong-Xian Pan, Benny Abraham Kaipparettu, Yair Lotan, Nagireddy Putluri
Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, USA. ., Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, Texas, USA., Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, USA., Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA., Advanced Technology Cores, Baylor College of Medicine, Houston, Texas, USA., Georgia Cancer Center, Augusta University, Augusta, Georgia, USA., Division of Pathology and Laboratory Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA., Division of Thoracic Surgery, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, Texas, USA., Scott Department of Urology, Baylor College of Medicine, Houston, Texas, USA., Department of Urology, Medical College of Georgia, Augusta, Georgia, USA., Department of Medicine, Harvard Medical School, Veterans Affairs Boston Healthcare System, Boston, Massachusetts, USA., Department of Urology, University of Texas Southwestern Medical Center, Dallas, Texas, USA., Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, USA. .