ABSTRACT
Targeting the programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) pathway represents a milestone in cancer therapy. However, the biologic features of diffuse large B-cell lymphoma (DLBCL) with PD-L1 expression remains unknown. We evaluated the correlation between pSYK and PD-L1 mRNA levels with RNAscope in situ hybridization and protein levels with immunohistochemistry in 108 cases of DLBCL, 25 of which featured loss of B-cell receptor (BCR), and investigated the effects of BCR signaling and MYC on PD-L1 mRNA and protein level with qPCR, immunoblotting and flow cytometery in DLBCL cell lines. PD-L1 amplification was detected with fluorescent in situ hybridization. Animal studies were applied to validate the in vitro findings. pSYK and MYC correlated with both PD-L1 mRNA and protein level. Genetic aberrations involving PD-L1 were rare in DLBCL. BCR signaling and MYC increased PD-L1 mRNA and protein expression. Inhibition of BCR signaling and BCR knockdown down-regulated PD-L1. DLBCL with a loss of loss of BCR showed low levels of PD-L1 mRNA and protein. PD-L1 was down-regulated by ibrutinib in a xenograft mouse model and correlated with slower tumor growth. In conclusion, this study demonstrates that DLBCL with PD-L1 expression features an activated B-cell receptor signal pathway, and that BCR inhibition and PD-L1 blockage may potentially synergize to targeting DLBCL.
Subject(s)
B7-H1 Antigen/metabolism , Lymphoma, Large B-Cell, Diffuse/metabolism , Proto-Oncogene Proteins c-myc/metabolism , Receptors, Antigen, B-Cell/metabolism , Adenine/analogs & derivatives , Adult , Aged , Aged, 80 and over , Animals , Female , Humans , Male , Mice, SCID , Middle Aged , Piperidines , Pyrazoles , Pyrimidines , Retrospective Studies , Signal Transduction , Syk Kinase/metabolism , Young AdultABSTRACT
PH domain leucine-rich repeat protein phosphatase 2 (PHLPP2) belongs to the phosphokinase family, that has been reported to play an important role in several cancers. However, the expression of PHLPP2 and its correlation with clinicopathologic characteristics in colorectal cancer (CRC) have yet to be determined. The aim of this study is to investigate the expression of PHLPP2 and explore its role in CRC. The expression of PHLPP2, PTEN, PI3KCA, and PI3KCB in 130 cases of CRC and normal tissues was assessed by immunohistochemistry. In addition, the expression of PHLPP2, PTEN, PI3KCA, and PI3KCB in 32 pairs of CRC tissues and their corresponding normal tissues was determined by RT-PCR and western blotting, respectively. PHLPP2 expression in CRC was significantly lower than that of normal tissues. However, PHLPP2 mRNA shows no significant difference between CRC and normal tissue. PTEN expression in left colorectal cancer (LCC) was absent, while PI3KCA and PI3KCB in right colorectal cancer (RCC) were significantly higher than those in LCC. PHLPP2 was negatively correlated with p-Akt1 in CRC. The expression of p-Akt1 in PHLPP2 (+)/PTEN (+) in CRC tissues was significantly lower than that in other groups. PHLPP2 expression was correlated with differentiation, invasion, and lymph node metastasis. Kaplan-Meier analysis and multivariate analysis reveal that PHLPP2 is closely related to prognosis; more importantly, it is an independent prognostic factor for CRC. In conclusion, PHLPP2 may play a major role in the development, metastasis, and prognosis of CRC.
