Evaluation of the PIK3 pathway in peripheral T‐cell lymphoma and NK/T‐cell lymphoma
Dachuan Huang, Tammy Song, Maarja‐Liisa Nairismägi, Yurike Laurensia, Wan‐Lu Pang, Daryl Cheah Ming Zhe, Esther Kam Yin Wong, Giovani Giovani‐Clarest Wijaya, Jing Tan, Sze Huey Tan, Jing Quan Lim, Burton Kuan Hui Chia, Jason Yongsheng Chan, Tiffany Tang, Nagavalli Somasundaram, Chee Leong Cheng, Oliver Politz, Ningshu Liu, Soon Thye Lim, Choon Kiat Ong
Abstract
Summary Peripheral T‐cell lymphomas (PTCL) and natural killer (NK)/T‐cell lymphomas (NKTCL) are a heterogeneous group of aggressive malignancies with dismal outcomes and limited treatment options. While the phosphatidylinositol 3‐kinase (PIK3) pathway has been shown to be highly activated in many B‐cell lymphomas, its therapeutic relevance in PTCL and NKTCL remains unclear. The aim of this study is to investigate the expression of PIK3 and phosphatase and tensin homolog (PTEN) in these subtypes of lymphoma and to identify potential therapeutic targets for clinical testing. Therefore, the expression of PIK3α, PIK3β, PIK3γ, PIK3δ and PTEN was analyzed in 88 cases of PTCL and NKTCL samples by immunohistochemistry. All PTCL and NKTCL samples demonstrated high expression of PIK3 isoforms. In particular, high PIK3α expression was significantly associated with poor survival, even after adjustment for age, International Prognostic Index (IPI) score and anthracycline‐based chemotherapy in first line. Notably, copanlisib, a pan‐class I inhibitor with predominant activities towards PIK3α and PIK3δ isoforms, effectively inhibited phosphorylation of AKT, 4E‐BP‐1 and STAT3, causing G 0 /G 1 cell cycle arrest and resulting in suppression of tumour cell growth in vitro and in vivo . This study provides evidence that targeting the PIK3 pathway, particularly simultaneous inhibition of PIK3α and δ, could be a promising approach for the treatment of PTCL and NKTCL.