Yuqin Song

Different sensitivity of germinal center B cell-like diffuse large B cell lymphoma cells towards ibrutinib treatment

BackgroundAlthough rituximab in the combination of CHOP chemotherapy has been widely used as the standard treatment for several kinds of B-cell non-Hodgkin lymphoma (B-NHL), a great number of B-NHL patients treated with this immunotherapy still develop primary and secondary resistance. Recently Bruton’s tyrosine kinase (Btk) inhibitor ibrutinib showed promising therapeutic effect in relapsed/refractory CLL and B-cell NHL, which provided essential alternatives for these patients.MethodsThe proliferation and apoptosis induction of tumor cells were measured by cell viability assay and Annexin-V staining. Western Blotting analysis and real-time PCR were used to detect the expression level of target proteins and chemokines production.ResultsWe demonstrated that ibrutinib inhibited the proliferation and induced apoptosis of GCB-DLBCL cell lines through suppression of BCR signaling pathway and activation of caspase-3. Furthermore, the chemokines CCL3 and CCL4 production from tumor cells were also found to be attenuated by ibrutinib treatment. But different cell lines exhibited distinct sensitivity after ibrutinib treatment. Interestingly, the decreasing level of p-ERK after ibrutinib treatment, but not the basal expression level of Btk, correlated with different drug sensitivity.ConclusionsIbrutinib could be a potentially useful therapy for GCB-DLBCL and the decreasing level of p-ERK could become a useful biomarker to predict related therapeutic response.

Chidamide in relapsed or refractory peripheral T cell lymphoma: a multicenter real-world study in China

The efficacy and safety of chidamide, a new subtype-selective histone deacetylase (HDAC) inhibitor, have been demonstrated in a pivotal phase II clinical trial, and chidamide has been approved by the China Food and Drug Administration (CFDA) as a treatment for relapsed or refractory peripheral T cell lymphoma (PTCL). This study sought to further evaluate the real-world utilization of chidamide in 383 relapsed or refractory PTCL patients from April 2015 to February 2016 in mainland China. For patients receiving chidamide monotherapy (n = 256), the overall response rate (ORR) and disease control rate (DCR) were 39.06 and 64.45%, respectively. The ORR and DCR were 51.18 and 74.02%, respectively, for patients receiving chidamide combined with chemotherapy (n = 127). For patients receiving chidamide monotherapy and chidamide combined with chemotherapy, the median progression-free survival (PFS) was 129 (95% CI 82 to 194) days for the monotherapy group and 152 (95% CI 93 to 201) days for the combined therapy group (P = 0.3266). Most adverse events (AEs) were of grade 1 to 2. AEs of grade 3 or higher that occurred in ≥5% of patients receiving chidamide monotherapy included thrombocytopenia (10.2%) and neutropenia (6.2%). For patients receiving chidamide combined with chemotherapy, grade 3 to 4 AEs that occurred in ≥5% of patients included thrombocytopenia (18.1%), neutropenia (12.6%), anemia (7.1%), and fatigue (5.5%). This large real-world study demonstrates that chidamide has a favorable efficacy and an acceptable safety profile for refractory and relapsed PTCL patients. Chidamide combined with chemotherapy may be a new treatment choice for refractory and relapsed PTCL patients but requires further investigation.

FCGR3A 158V/F Polymorphism and Response to Frontline R-CHOP Therapy in Diffuse Large B-Cell Lymphoma

The influence of Fc gamma receptor IIIA (FCGR3A) 158V/F polymorphisms on the response to rituximab (R) plus CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone; R-CHOP) therapy in diffuse large B-cell lymphoma (DLBCL) is uncertain. Thus, a retrospective study and a meta-analysis were performed to examine the possible correlation between FCGR3A 158V/F polymorphism and the response rate of R-CHOP regimen in patients with newly diagnosed DLBCL. The genotypes of FCGR3A 158V/F in 164 newly diagnosed DLBCL patients treated with R-CHOP were determined in this retrospective study. Additionally, a meta-analysis of current and previously published studies was conducted. Overall response rate (complete and partial response, ORR) and complete response rate (CR) were evaluated. The results of our retrospective study showed lack of correlation between FCGR3A 158V/F polymorphism and ORR (p=0.78) or CR (p=0.76) with R-CHOP therapy. A meta-analysis of 731 cases also showed lack of significant association of ORR and CR in all genetic models with FCGR3A 158V/F polymorphism. In survival analysis, the homozygous F genotype correlated with a shorter progression-free survival than that of non-F/F genotype (p=0.05), this was significant for the non-GC subset of DLBCL (p=0.04), but no association was found between overall survival and FCGR3A 158V/F polymorphism. Further analysis with nonsuperiority test (p<0.0001) suggested that FCGR3A 158V/F polymorphism was not associated with better ORR or CR in newly diagnosed DLBCL patient treated with R-CHOP. No clear relationship was found between FCGR3A 158V/F polymorphism and response to frontline R-CHOP therapy in patients with DLBCL.

Histone deacetylase 6 activity is critical for the metastasis of Burkitt?s lymphoma cells

BackgroundBurkitt’s lymphoma is an aggressive malignancy with high risk of metastasis to extranodal sites, such as bone marrow and central nervous system. The prognosis of metastatic Burkitt’s lymphoma is poor. Here we sought to identify a role of histone deacetylase 6 (HDAC6) in the metastasis of Burkitt’s lymphoma cells.MethodsBurkitt’s lymphoma cells were pharmacologically treated with niltubacin, tubacin or sodium butyrate (NaB) or transfected with siRNAs to knock down the expression of HDAC6. Cell migration and invasion ability were measured by transwell assay, and cell cycle progression was analyzed by flow cytometry. Cell adhesion and proliferation was determined by CellTiter-Glo luminescent cell viability assay kit. Cell morphological alteration and microtubule stability were analyzed by immunofluorescence staining. Effect of niltubacin, tubacin and NaB on acetylated tubulin and siRNA efficacy were measured by western blotting.ResultsSuppression of histone deacetylase 6 activity significantly compromised the migration and invasion of Burkitt’s lymphoma cells, without affecting cell proliferation and cell cycle progression. Mechanistic study revealed that HDAC6 modulated chemokine induced cell shape elongation and cell adhesion probably through its action on microtubule dynamics.ConclusionsWe identified a critical role of HDAC6 in the metastasis of Burkitt’s lymphoma cells, suggesting that pharmacological inhibition of HDAC6 could be a promising strategy for the management of metastatic Burkitt’s lymphoma.

Pharmacokinetics of obinutuzumab in Chinese patients with B‐cell lymphomas

Aim The Phase Ib GERSHWIN study (NCT01680991) assessed the pharmacokinetic (PK) profile of obinutuzumab following multiple intravenous (i.v.) doses to Chinese patients with B‐cell lymphomas, and compared findings with previous obinutuzumab PK studies in mainly Caucasian (non‐Chinese) patients. Methods GERSHWIN was an open‐label, single‐arm intervention study. Patients aged >18 years with CD20+ relapsed/refractory chronic lymphocytic leukaemia (CLL), diffuse large B‐cell lymphoma (DLBCL) or follicular lymphoma (FL) were enrolled from four centres in China. The treatment period was 24 weeks; patients received obinutuzumab 1000 mg i.v. on Days (D)1, 8 and 15 of Cycle (C)1 (CLL patients: first infusion split over 2 days) and on D1 of C2–8 (all cycles: 21 days). PK parameters were estimated using non‐compartmental analysis (NCA), and a population PK analysis was used to determine whether observed GERSHWIN PK data were in accordance with previous obinutuzumab PK studies in non‐Chinese patients. Results The PK analysis population included 48 patients: 28 patients completed all treatment cycles. NCA showed a similar PK profile in Chinese patients with FL, DLBCL and CLL. Steady‐state concentrations of obinutuzumab appeared to be reached at the start of C2 irrespective of histology. There was no apparent relationship between body weight and systemic exposure. Most PK profiles observed in GERSHWIN lay within the 90% prediction interval of simulated profiles. Conclusions Obinutuzumab exposure was comparable in CLL, DLBCL and FL patients. NCA and population PK analysis indicate that PK characteristics of Chinese patients with B‐cell lymphomas are similar to those in non‐Chinese patients.

Safety and efficacy of bevacizumab combined with R-CHOP regimen in seven Chinese patients with untreated diffuse large B-cell lymphoma.

BackgroundRituximab plus CHOP (R-CHOP) significantly improved the outcome of diffuse large B cell lymphoma (DLBCL), a common sub-type of non-Hodgkin lymphoma. But 40% – 50% of DLBCL patients cannot be cured by this regimen. Some clinical trials showed that bevacizumab might be useful in the treatment of DLBCL. This study evaluated the safety and efficacy of bevacizumab combined with the R-CHOP (A-R-CHOP) regimen in Chinese patients with previously untreated DLBCL.MethodsPatients with previously untreated DLBCL received A-R-CHOP regimen therapy. All patients with complete response (CR)/ unconfirmed complete response(CRu) after 8 cycles of A-R-CHOP received the bevacizumab maintenance therapy once every 3 weeks. The remained bulky disease was treated with radiotherapy.ResultsSeven Chinese patients were treated. All of them had bulky diseases. One patient had progressive disease after 4 cycles of A-R-CHOP therapy. The rest six patients completed 8 cycles of A-R-CHOP treatment. All of these six patients reached CR/CRu (5 CR, 1 CRu). Bevacizumab maintenance therapy was given to 4 CR patients. All 7 patients experienced Grade 3/4 hematologic adverse events; additionally, one had Grade 3 gastrointestinal toxicity and one had Grade 1 epistaxis. During bevacizumab maintenance therapy, one patient had Grade 1 gingival bleeding, another experienced Grade 1 proteinuria and then Grade 3 congestive heart failure 4 months after completion of maintenance therapy. At the end of July 2013, the patient who had progressive disease after 4 cycles of A-R-CHOP died of progressive disease, the other six remained CR response.ConclusionsThe A-R-CHOP regimen is effective for untreated DLBCL, but may cause bevacizumab-specific toxicities, which should be monitored.

The mTOR kinase inhibitor everolimus synergistically enhances the anti-tumor effect of the Bruton's tyrosine kinase (BTK) inhibitor PLS-123 on Mantle cell lymphoma

Mantle cell lymphoma (MCL) is an aggressive and incurable malignant disease. Despite of general chemotherapy, relapse and mortality are common, highlighting the need for the development of novel targeted drugs or combination of therapeutic regimens. Recently, several drugs that target the B‐cell receptor (BCR) signaling pathway, especially the Brutons tyrosine kinase (BTK) inhibitor ibrutinib, have demonstrated notable therapeutic effects in relapsed/refractory patients, which indicate that pharmacological inhibition of BCR pathway holds promise in MCL treatment. Here, we have developed a novel irreversible BTK inhibitor, PLS‐123, that has more potent and selective anti‐tumor activity than ibrutinib in vitro and in vivo. Using in vitro screening, we discovered that the combination of PLS‐123 and the mammalian target of rapamycin (mTOR) inhibitor everolimus exert synergistic activity in attenuating proliferation and motility of MCL cell lines. Simultaneous inhibition of BTK and mTOR resulted in marked induction of apoptosis and cell cycle arrest in the G1 phase, which were accompanied by upregulation of pro‐apoptotic proteins (cleaved Caspase‐3, cleaved PARP and Bax), repression of anti‐apoptotic proteins (Mcl‐1, Bcl‐xl and XIAP), and downregulation of regulators of the G1/S phase transition (CDK2, CDK4, CDK6 and Cyclin D1). Gene expression profile analysis revealed simultaneous treatment with these agents led to inhibition of the JAK2/STAT3, AKT/mTOR signaling pathways and SGK1 expression. Finally, the anti‐tumor and pro‐apoptotic activities of combination strategy have also been demonstrated using xenograft mice models. Taken together, simultaneous suppression of BTK and mTOR may be indicated as a potential therapeutic modality for the treatment of MCL.

Genetic polymorphisms of STAT3 correlated with prognosis in diffuse large B-cell lymphoma patients treated with rituximab

BackgroundRituximab in the combination of CHOP chemotherapy has been widely used as the standard treatment for several kinds of B-cell non-Hodgkin lymphoma (B-NHL). Inactivation of phosphorylation of STAT3 plays an essential role in rituximab-induced anti-proliferative activity in B-cell lymphoma. However, the relationship between STAT3 genetic polymorphisms and clinical response to standard frontline treatment with rituximab has not been well illustrated yet.MethodsIn this study we analyzed the STAT3 polymorphisms and prognosis of 166 diffuse large B-cell lymphoma (DLBCL) patients who were treated with rituximab from 2007 to 2010. Determination of the STAT3 polymorphisms of rs2293152 from genomic DNA was achieved by Sanger chain termination sequencing.ResultsWe did not observe obvious correlation between patients’ disease features and STAT3 polymorphisms, but patients with homozygous genotypes at rs2293162 showed a trend of higher CR rate than those with the heterozygous genotype, especially in non-GCB subgroup (p = 0.011). Furthermore, homozygous genotypes GG and CC also showed advantages of long-term survival compared with heterozygous genotype patients (p = 0.022).ConclusionsThese results suggest that STAT3 polymorphisms could be a suitable biomarker related to clinical outcome of DLBCL patients treated with rituximab.

Thiamet-G-mediated inhibition of O-GlcNAcase sensitizes human leukemia cells to microtubule-stabilizing agent paclitaxel

Although the microtubule-stabilizing agent paclitaxel has been widely used for treatment of several cancer types, particularly for the malignancies of epithelia origin, it only shows limited efficacy on hematological malignancies. Emerging roles of O-GlcNAcylation modification of proteins in various cancer types have implicated the key enzymes catalyzing this reversible modification as targets for cancer therapy. Here, we show that the highly selective O-GlcNAcase (OGA) inhibitor thiamet-G significantly sensitized human leukemia cell lines to paclitaxel, with an approximate 10-fold leftward shift of IC50. Knockdown of OGA by siRNAs or inhibition of OGA by thiamet-G did not influence the cell viability. Furthermore, we demonstrated that thiamet-G binds to OGA in competition with 4-methylumbelliferyl N-acetyl-β-d-glucosaminide dehydrate, an analogue of O-GlcNAc UDP, thereby suppressing the activity of OGA. Importantly, inhibition of OGA by thiamet-G decreased the phosphorylation of microtubule-associated protein Tau and caused alterations of microtubule network in cells. It is noteworthy that paclitaxel combined with thiamet-G resulted in more profound perturbations on microtubule stability than did either one alone, which may implicate the underlying mechanism of thiamet-G-mediated sensitization of leukemia cells to paclitaxel. These findings thus suggest that a regimen of paclitaxel combined with OGA inhibitor might be more effective for the treatment of human leukemia.

Can the SUVmax-liver-based interpretation improve prognostic accuracy of interim and posttreatment 18F-FDG PET/CT in patients with diffuse large B-cell lymphoma?

Abstract In order to investigate whether the SUVmax-liver-based interpretation could improve prognostic accuracy of interim (PET-4) and posttreatment PET/CT (PET-end), 115 patients with newly diagnosed DLBCL were recruited in the study. ROC analysis revealed the optimal threshold is 1.6-fold of SUVmax-liver for PET-4 and 1.4-fold of SUVmax-liver for PET-end. The SUVmax-liver-based interpretation had a perfect interobserver agreement, higher prognostic accuracy and positive predictive value than 5-point scale and %ΔSUVmax criteria in both PET-4 and PET-end. Dramatic differences in the outcome between patients with positive and negative PET-4/PET-end were demonstrated using Kaplan–Meier survival curves (p < .05). Univariate and multifactor analysis found PET-4 and PET-end were independent prognostic factors for the outcome of DLBCL. In conclusion, the SUVmax-liver-based interpretation were superior to 5-point scale and %ΔSUVmax criteria in analyzing the PET-4 and PET-end for the prognosis of DLBCL patients.