Synergy of DNA methylation and histone deacetylase inhibitors in the re-expression of RASSF1A and P16 genes silenced in QBC cells

Objective: To investigate the effects of DNA methylation and histone deacetylase inhibitors in the re-expression of P16 and RASSIF1A of QBC939. Methods: The QBC939 cells were treated with hydralazine and valproate either alone or combined, and the control group was added with RPIM-1640 culture medium. After 48 h, the expression of P16 and RASSF1A genes were evaluated by reverse transcription-PCR, Western blot, and the methylation status of the two genes were detected with MSP (methylation specific PCR). Results: Hydralazine and valproate could induce demethylation of the promoter region of the two genes, and could make them re-active. The expressions of P16 and RASSF1A of cells treated with both drugs were higher than that of the cells treated with either hydralazine or valproate (P < 0.01). There was no RASSF1A gene, and few P16 gene expressing in the control group. The demethylation effect could be found in the groups treated with hydralazine or both drugs, whereas no demethylation effect happened in the valproate group. Conclusion: The two drugs could synergistically re-express P16 and RASSF1A genes silenced in QBC939, and they exerted a great anti-tumour effect on QBC cells.

Chidamide,Decitabine,Cytarabine,Aclarubicin,and Granulocyte Colony-stimulating Factor Therapy for Patients with Relapsed/Refractory Acute Myeloid Leukemia:A Retrospective Study from a Single-Center

Objective Preclinical evidence and clinical trials have suggested synergistic effects of epigenetic modifiers in combination with cytotoxic agents for the treatment of leukemia.However,their efficacy in patients with relapsed/refractory acute myeloid leukemia(R/R AML)remains unclear.Methods Clinical data of R/R AML patients who received a CDCAG regimen(chidamide,decitabine,cytarabine,aclarubicin,and granulocyte colony-stimulating factor)from July 1,2018 to October 31,2021 at our center were retrospectively assessed,and the safety and efficacy of the CDCAG regimen were evaluated.Patients were followed up until November 30,2021,with a median follow-up of 21.6 months(95%CI:10.0–33.2 months).Results A total of 67 patients were enrolled.Two patients died within 3 weeks after the initiation,and therefore only 65 patients underwent the assement for clinical response and survival.It was found that 56.9%patients achieved complete remission with a median overall survival(OS)of 9.6 months.The median OS of responders was 25.9 months,while that of non-responders was 5.0 months(P<0.0001).Patients with gene mutations had a superior overall response rate(ORR)(80.4%vs.45.5%,P=0.043)compared to those without gene mutations.The presence of DNA methyltransferase 3 A(DNMT3A),ten-eleven translocation-2(TET2),and isocitrate dehydrogenase 1/2(IDH1/2)mutations did not affect the response rate(88.2%vs.68.9%,P=0.220)and reflected a better OS(not attained vs.9.0 months,P=0.05).The most common non-hematologic adverse events were pulmonary infection(73.1%),followed by febrile neutropenia(23.9%)and sepsis(19.4%).Conclusions The CDCAG regimen was effective and well-tolerated in R/R AML patients,increasing the potential for allogeneic hematopoietic stem cell transplantation.Moreover,patients with DNMT3A,TET2,and IDH1/2 mutations might benefit from this regimen.

Epigenetic modulators for brain cancer stem cells: Implications for anticancer treatment

Primary malignant brain tumors are a major cause of morbidity and mortality in both adults and children,with a dismal prognosis despite multimodal therapeutic approaches.In the last years,a specific subpopulation of cells within the tumor bulk,named cancer stem cells(CSCs)or tumor-initiating cells,have been identified in brain tumors as responsible for cancer growth and disease progression.Stemness features of tumor cells strongly affect treatment response,leading to the escape from conventional therapeutic approaches and subsequently causing tumor relapse.Recent research efforts have focused at identifying new therapeutic strategies capable of specifically targeting CSCs in cancers by taking into consideration their complex nature.Aberrant epigenetic machinery plays a key role in the genesis and progression of brain tumors as well as inducing CSC reprogramming and preserving CSC characteristics.Thus,reverting the cancer epigenome can be considered a promising therapeutic strategy.Three main epigenetic mechanisms have been described:DNA methylation,histone modifications,and non-coding RNA,particularly microRNAs.Each of these mechanisms has been proven to be targetable by chemical compounds,known as epigeneticbased drugs or epidrugs,that specifically target epigenetic marks.We review here recent advances in the study of epigenetic modulators promoting and sustaining brain tumor stem-like cells.We focus on their potential role in cancer therapy.

Epigenetic regulation of dental pulp stem cells and its potential in regenerative endodontics

Regenerative endodontics(RE)therapy means physiologically replacing damaged pulp tissue and regaining functional dentin–pulp complex.Current clinical RE procedures recruit endogenous stem cells from the apical papilla,periodontal tissue,bone marrow and peripheral blood,with or without application of scaffolds and growth factors in the root canal space,resulting in cementum-like and bone-like tissue formation.Without the involvement of dental pulp stem cells(DPSCs),it is unlikely that functional pulp regeneration can be achieved,even though acceptable repair can be acquired.DPSCs,due to their specific odontogenic potential,high proliferation,neurovascular property,and easy accessibility,are considered as the most eligible cell source for dentin–pulp regeneration.The regenerative potential of DPSCs has been demonstrated by recent clinical progress.DPSC transplantation following pulpectomy has successfully reconstructed neurovascularized pulp that simulates the physiological structure of natural pulp.The self-renewal,proliferation,and odontogenic differentiation of DPSCs are under the control of a cascade of transcription factors.Over recent decades,epigenetic modulations implicating histone modifications,DNA methylation,and noncoding(nc)RNAs have manifested as a new layer of gene regulation.These modulations exhibit a profound effect on the cellular activities of DPSCs.In this review,we offer an overview about epigenetic regulation of the fate of DPSCs;in particular,on the proliferation,odontogenic differentiation,angiogenesis,and neurogenesis.We emphasize recent discoveries of epigenetic molecules that can alter DPSC status and promote pulp regeneration through manipulation over epigenetic profiles.