Synergistic anticancer effect of a combination of chidamide and etoposide against NK/T cell lymphoma

Chidamide Induces Epstein-Barr Virus (EBV) Lytic Infection and Acts Synergistically with Tenofovir to Eliminate EBV-Positive Burkitt Lymphoma

Epstein-Barr virus (EBV) is a type of human γ-herpesvirus, and its reactivation plays an important role in the development of EBV-driven Burkitt lymphoma (BL). Despite intensive chemotherapy, the prognosis of relapsed/refractory BL patients remains unfavorable, and a definitive method to completely eliminate latent EBV infection is lacking. Previous studies have demonstrated that histone deacetylase (HDAC) inhibitors can induce the transition of EBV from latency to the lytic phase. The lytic activation of EBV can be inhibited by tenofovir, a potent inhibitor of DNA replication. Herein, we explored the antitumor effect and EBV clearance potential of a novel HDAC inhibitor called chidamide, combined with tenofovir, in the treatment of EBV-positive BL. In the study, chidamide exhibited inhibitory activity against HDAC. Moreover, chidamide inhibited BL cell proliferation, arrested cell cycle progression, and induced BL cell apoptosis primarily by regulating the MAPK pathways. Additionally, chidamide promoted the transcription of lytic genes, including BZLF1, BMRF1, and BMLF1 Compared with chidamide alone, the addition of tenofovir further induced growth arrest and apoptosis in EBV-positive BL cells and inhibited the transcriptions of EBV lytic genes induced by chidamide alone. Furthermore, our in vivo data demonstrated that the combination of chidamide and tenofovir had superior tumor-suppressive effects in a mouse model of BL cell tumors. The aforementioned findings confirm the synergistic effect of chidamide combined with tenofovir in inducing growth inhibition and apoptosis in EBV-positive BL cells and provide an effective strategy for eliminating EBV and EBV-associated malignancies. SIGNIFICANCE STATEMENT: High levels of Epstein-Barr virus (EBV)-DNA have consistently been associated with unfavorable progression-free survival and overall survival in EBV-associated lymphomas. Therefore, identifying novel strategies to effectively eradicate tumor cells and eliminate EBV is crucial for lymphoma patients. This study confirmed, for the first time, the synergistic effect of chidamide combined with tenofovir in the treatment of Burkitt lymphoma and the eradication of EBV virus.

Chidamide: Targeting epigenetic regulation in the treatment of hematological malignancy

Epigenetic alterations frequently participate in the onset of hematological malignancies. Histone deacetylases (HDACs) are essential for regulating gene transcription and various signaling pathways. Targeting HDACs has become a novel treatment option for hematological malignancies. Chidamide is the first oral selective HDAC inhibitor for HDAC1, HDAC2, HDAC3, and HDAC10 and was first approved for the treatment of R/R peripheral T-cell lymphoma by the China Food and Drug Administration in 2014. Chidamide was also approved under the name Hiyasta (HBI-8000) in Japan in 2021. In vitro studies revealed that chidamide could inhibit proliferation and induce apoptosis via cell cycle arrest and the regulation of apoptotic proteins. In clinical studies, chidamide was also efficacious in multiple myeloma, acute leukemia and myelodysplastic syndrome. This review includes reported experimental and clinical data on chidamide monotherapy or chidamide treatment in combination with chemotherapy for various hematological malignancies, offering a rationale for the renewed exploration of this drug.

Etoposide, dexamethasone, and pegaspargase with sandwiched radiotherapy in early-stage natural killer/T-cell lymphoma: A randomized phase III study

Methotrexate, etoposide, dexamethasone, and pegaspargase (MESA) with sandwiched radiotherapy is known to be effective for early-stage extranodal natural killer/T-cell lymphoma, nasal type (NKTCL). We explored the efficacy and safety of reduced-intensity, non-intravenous etoposide, dexamethasone, and pegaspargase (ESA) with sandwiched radiotherapy. This multicenter, randomized, phase III trial enrolled patients aged between 14 and 70 years with newly diagnosed early-stage nasal NKTCL from 27 centers in China. Patients were randomly assigned (1:1) to receive ESA (pegaspargase 2,500 IU/m² intramuscularly on day 1, etoposide 200 mg orally, and dexamethasone 40 mg orally on days 2-4) or MESA (methotrexate 1 g/m² intravenously on day 1, etoposide 200 mg orally, and dexamethasone 40 mg orally on days 2-4, and pegaspargase 2,500 IU/m² intramuscularly on day 5) regimen (four cycles), combined with sandwiched radiotherapy. The primary endpoint was overall response rate (ORR). The non-inferiority margin was -10.0%. From March 16, 2016, to July 17, 2020, 256 patients underwent randomization, and 248 (ESA [n = 125] or MESA [n = 123]) made up the modified intention-to-treat population. The ORR was 88.8% (95% confidence interval [CI], 81.9-93.7) for ESA with sandwiched radiotherapy and 86.2% (95% CI, 78.8-91.7) for MESA with sandwiched radiotherapy, with an absolute rate difference of 2.6% (95% CI, -5.6-10.9), meeting the non-inferiority criteria. Per-protocol and sensitivity analysis supported this result. Adverse events of grade 3 or higher occurred in 42 (33.6%) patients in the ESA arm and 81 (65.9%) in the MESA arm. ESA with sandwiched radiotherapy is an effective, low toxicity, non-intravenous regimen with an outpatient design, and can be considered as a first-line treatment option in newly diagnosed early-stage nasal NKTCL.

Integrated driver mutations profile of chinese gastrointestinal-natural killer/T-cell lymphoma

Background

One of the most common nasal external sites in extranodal Natural Killer/T-cell lymphoma (NKTCL) is in the gastrointestinal (GI) system. Despite this, reports on gastrointestinal-Natural Killer/T-cell lymphoma (GI-NKTCL) are very few. To obtain a better understanding of this manifestation of NKTCL, we conducted a retrospective study on GI-NKTCL to analyze its clinical features, genomic changes and immune infiltration.

Methods

We retrospectively collected patients diagnosed with GI-NKTCL in the Sixth Affiliated Hospital of Sun Yat-sen University from 2010 to 2020. From this cohort we obtained mutation data via whole exome sequencing.

Results

Genomic analysis from 15 patients with GI-NKTCL showed that the most common driving mutations were ARID1B(14%, 2/15), ERBB3(14%, 2/15), POT1(14%, 2/15), and TP53(14%, 2/15). In addition, we found the most common gene mutation in patients with GI-NKTCL to be RETSAT(29%, 4/15) and SNRNP70(21%, 3/15), and the most common hallmark pathway mutations to be G2M checkpoint pathway (10/15, 66.7%), E2F targets (8/15, 53.3%), estrogen response late (7/15, 46.7%), estrogen response early (7/15, 46.7%), apoptosis (7/15, 46.7%) and TNFA signaling via NFKB (7/15, 46.7%). In the ICIs-Miao cohort, SNRNP7-wild-type (WT) melanoma patients had significantly prolonged overall survival (OS) time compared with SNRNP7 mutant type (MT) melanoma patients. In the TCGA-UCEC cohort, the patients with RETSAT-MT or SNRNP7-MT had significantly increased expression of immune checkpoint molecules and upregulation of inflammatory immune cells.

Conclusions

In this study, we explored GI-NKTCL by means of genomic analysis, and identified the most common mutant genes (RETSAT and SNRNP70), pathway mutations (G2M checkpoint and E2F targets) in GI-NKTCL patients. Also, we explored the association between the common mutant genes and immune infiltration. Our aim is that our exploration of these genomic changes will aid in the discovery of new biomarkers and therapeutic targets for those with GI-NKTCL, and finally provide a theoretical basis for improving the treatment and prognosis of patients with GI-NKTCL.