Angioimmunoblastic T cell lymphoma (AITL) is a distinct subtype of peripheral T cell lymphoma and associated with poor outcomes. The activation status of T cell receptor (TCR) signaling has recently become a focus of attention in terms of the therapeutic targets. However, the molecular pathogenesis mechanisms and novel therapeutic targets are largely unknown. Antibodies specific to phosphorylated ZAP70, ITK and PLCγ1 were used to identify the activation status of intracellular proteins involved in TCR signaling in AITL patients. Malignant T cell lymphoma cells were transduced with a lentiviral construct containing ITK shRNA for cellular and functional assays. The antitumor effects of the selective ITK inhibitor BMS-509744 were determined in vitro and in vivo. Immunohistochemistry staining showed that more than half of the AITL patients (n = 38) exhibited continuously activated intracellular TCR signaling pathway. Patients positive for phosphorylated ITK showed a lower rate of complete response (20% vs. 75%, P = 0.004) and a shorter progression-free survival (5.17 months vs. 25.1 months, P = 0.022) than patients negative for phosphorylated ITK. Genetic and pharmacological cellular ITK inhibition significantly compromised the proliferation, invasion and migration of malignant T cells. The selective ITK inhibitor BMS-509744 also induced the pro-apoptotic effects and G2/M phase cell cycle arrest in vitro and in vivo. Finally, inhibition of ITK synergistically enhanced the antitumor effect of vincristine and doxorubicin on malignant T cell lymphoma cell lines. Our findings suggest that ITK may be a novel candidate therapeutic target for the treatment of patients with ITK-expressing malignant T-cell lymphomas.

Diffuse large B cell lymphoma (DLBCL) is the most common form of lymphoma. Although durable remissions can be achieved in more than half of these patients, DLBCL remains a significant clinical challenge, with approximately 30% of patients not being cured. BCR-associated kinases (SYK, BTK, and PI3K) inhibitors have exhibited encouraging pre-clinical and clinical effects, as reported by many researchers. Early studies demonstrated that protein kinase C-β (PKCβ) inhibitors alter phosphorylation level the Bruton’s tyrosine kinase (BTK), which leads to enhanced BTK signaling. Here, for the first time, we investigate whether the combination of PKCβ inhibitor enzastaurin and BTK inhibitor ibrutinib has synergistic anti-tumor effects in DLBCL. In vitro cell proliferation was analyzed using Cell Titer-Glo Luminescent Cell Viability Assay. Induction of apoptosis and cell cycle arrest were measured by flow cytometry. Western Blotting analysis was used to detect the essential regulatory enzymes in related signaling pathways. RNA-seq was conducted to evaluate the whole transcriptome changes brought by co-treatment with low doses of enzastaurin and ibrutinib. The synergistic anti-tumor effects of enzastaurin and ibrutinib were also evaluated in vivo. Combination of enzastaurin and ibrutinib produced a lasting synergistic effect on the survival and proliferation of DLBCL cells, including reduction of proliferation, promoting apoptosis, inducting G1 phase arrest, preventing cell invasion and migration, and down-regulating activation of downstream signaling. More importantly, whole-transcriptome changes results showed that combination therapy worked synergistically to regulate whole-transcriptome expression compared with enzastaurin and ibrutinib alone. Co-treatment with low doses of enzastaurin and ibrutinib could effectively downregulate BCR, NF-κB, JAK and MAPK related signaling pathway. Furthermore, the mRNA expression analysis further indicated that co-treatment significantly decreased the mRNA levels of NOTCH1. The combination effect in inhibiting proliferation of DLBCL cells probably was realized through suppression of NOTCH1 expression. Finally, the anti-tumor activity of co-treatment also was demonstrated in vivo. Combination of enzastaurin and ibrutinib had synergistic anti-tumor effects in DLBCL, independent of molecular subtype. These results provided a sound foundation for an attractive therapeutic treatment, and the simultaneous suppression of BTK and PKCβ might be a new treatment strategy for DLBCL.

Mantle cell lymphoma (MCL) is an incurable B cell-derived malignant tumor with a median overall survival of 4–5 years. Mer tyrosine kinase (MerTK) has been reported to be aberrantly expressed in leukemia, melanoma, and gastric cancer, and plays a pivotal role in the process of oncogenesis. This study assessed the role of MerTK in MCL for the first time. Immunohistochemistry and western blot were performed to figure out expression of MerTK in MCL. MerTK inhibition by either shRNA or treatment with UNC2250 (a MerTK-selective small molecular inhibitor) was conducted in MCL cell lines. MCL-cell-derived xenograft models were established to evaluate the anti-tumor effects of UNC2250 in vivo. MerTK was ectopically expressed in four of six MCL cell lines. Sixty-five of 132 (48.9%) MCL patients showed positive expression of MerTK. MerTK inhibition by either shRNA or treatment with UNC2250 decreased activation of downstream AKT and p38, inhibited proliferation and invasion in MCL cells, and sensitized MCL cells to treatment with vincristine in vitro and doxorubicin in vitro and in vivo. UNC2250 induced G2/M phase arrest and prompted apoptosis in MCL cells, accompanied by increased expression of Bax, cleaved caspase 3 and poly (ADP-ribose) polymerase, and decreased expression of Bcl-2, Mcl-1 and Bcl-xL. Moreover, UNC2250 delayed disease progression in MCL-cell-derived xenograft models. Our data prove that ectopic MerTK may be a novel therapeutic target in MCL, and further pre-clinical or even clinical studies of UNC2250 or new MerTK inhibitors are essential and of great significance.

TP53 Arg72Pro (SNP rs1042522) is associated with risk of non-Hodgkin lymphoma (NHL). Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of NHL. However, the relationship between this SNP and prognosis of DLBCL in Asians is unknown. Genotyping of TP53 Arg72Pro was done in 425 Chinese DLBCL patients. Two hundred and eighty-nine patients were treated with R-CHOP, and 136 patients received CHOP or CHOP-like as frontline regimen. Three hundred and ninety-six patients were assessable for the efficacy. Patients with Arg/Arg and Arg/Pro at codon 72 of TP53 had a higher complete response rate (61% vs. 44%, P = 0.007) than those with Pro/Pro. In the subgroup treated with CHOP or CHOP-like therapy, patients with Arg/Arg and Arg/Pro showed a higher 5-year overall survival (OS) rate than those with Pro/Pro (68.8% vs. 23.2%, P = 0.001). Multivariate Cox regression analysis revealed TP53 Arg72 as a favorable prognostic factor in this group. However, the combination of rituximab with CHOP significantly increased the 5-year OS rate of patients with Pro/Pro to 63%. This study revealed TP53 Arg72 as a favorable prognostic factor for Chinese DLBCL patients treated with CHOP or CHOP-like as frontline therapy.

Rituximab combined with cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP) is used as standard frontline regimen for diffuse large B-cell lymphoma (DLBCL). The landscape of somatic mutations in DLBCL revealed that inactivation of EP300 plays an important role in lymphomagenesis. A common EP300 single nucleotide polymorphism (SNP) rs20551 results in the substitution of valine for isoleucine at codon 997 close to the Bromodomain. However, the association between SNP rs20551 and clinical prognosis in DLBCL patients treated with R-CHOP is unknown. In this study we analyzed the EP300 SNP rs20551 and prognosis of 226 DLBCL patients who treated with R-CHOP or R-CHOP-like regimes from 2002 to 2013. Determination of the EP300 SNP rs20551 from genomic DNA was obtained by Sanger chain termination sequencing. In this study, the frequency of the A and G allele of the EP300 SNP rs20551 in 226 patients were 92.5 and 7.5%, respectively. We did not observe obvious correlation between patients’ disease features and the EP300 SNP rs20551. But the patients with genotype AA had a higher 5-year overall survival rate than those with genotype GA (77.0% vs. 64.7%, p = 0.045). Furthermore, multivariate Cox regression analysis showed that the GA genotype of EP300 SNP rs20551 was an independent poor prognostic factor for DLBCL patients treated with Rituximab-chemotherapy (p = 0.009, HR 2.956, 95% CI 1.315–6.645). This study suggests that EP300 SNP rs20551 might be a useful biomarker to predict the long-term outcome of R-CHOP in DLBCL patients.