Resistance to venetoclax and hypomethylating agents in acute myeloid leukemia

Despite the success of the combination of venetoclax with the hypomethylating agents(HMA)decitabine or azacitidine in inducing remission in older,previously untreated patients with acute myeloid leukemia(AML),resistance-primary or secondary-still constitutes a significant roadblock in the quest to prolong the duration of response.Here we review the proposed and proven mechanisms of resistance to venetoclax monotherapy,HMA monotherapy,and the doublet of venetoclax and HMA for the treatment of AML.We approach the mechanisms of resistance to HMAs and venetoclax in the light of the agents’mechanisms of action.We briefly describe potential therapeutic strategies to circumvent resistance to this promising combination,including alternative scheduling or the addition of other agents to the HMA and venetoclax backbone.Understanding the mechanisms of action and evolving resistance in AML remains a priority in order to maximize the benefit from novel drugs and combinations,identify new therapeutic targets,define potential prognostic markers,and avoid treatment failure.

Revolutionizing Non-Invasive Biomarker Discoveries: The Power of Methylation Screening Analysis in Cell-Free DNA Liquid Biopsy

Epigenetic changes of DNA, including methylation, have long been recognized as key indicators of various diseases, including aging, cancer, and neurological disorders. Biomarker discoveries based on distinct methylation patterns for both hypermethylation and hypomethylation lead the way in discovery of novel diagnosis and treatment targets. Many different approaches are present to detect the level of methylation in whole genome (whole genome bisulfite sequencing, microarray) as well as at specific loci (methylation specific PCR). Cell-free DNA (cf-DNA) found in body fluids like blood provides information about DNA methylation and serves as a less invasive approach for genetic screening. Cell-free DNA and methylation screening technologies, when combined, have the potential to transform the way we approach genetic screening and personalized therapy. These technologies can help enhance disease diagnostic accuracy and inform the development of targeted therapeutics by providing a non-invasive way for acquiring genomic information and identifying disease-associated methylation patterns. We highlight the clinical benefits of using cell-free DNA (cf-DNA) liquid biopsy analysis and available methylation screening technologies that have been crucial in identifying biomarkers for disease from patients using a non-invasive way. Powering such biomarker discoveries are various methods of cf-DNA methylation analysis such as Bisulfite Sequencing and most recently, Methylation-Specific Restriction Enzyme (MSRE-seq) Analysis, paving the way for novel epigenetic biomarker discoveries for more robust diagnosis such as early disease detection, prognosis, monitoring of disease progression and treatment response as well as discovery of novel drug targets.

Relapsed/refractory classical Hodgkin lymphoma effectively treated with low-dose decitabine plus tislelizumab:A case report

BACKGROUND Academic studies have proved that anti-programmed death-1(PD-1)monoclonal antibodies demonstrated remarkable activity in relapsed/refractory classical Hodgkin lymphoma(cHL).However,most patients ultimately experienced failure or resistance.It is urgent and necessary to develop a novel strategy for relapsed/refractory cHL.The aim of this case report is to evaluate the combination approach of low-dose decitabine plus a PD-1 inhibitor in relapsed/refractory cHL patients with prior PD-1 inhibitor exposure.CASE SUMMARY The patient was a 27-year-old man who complained of enlarged right-sided cervical lymph nodes and progressive pain aggravation of the right shoulder over the past 3 mo before admission.Histological analysis of lymph node biopsy was suggestive of cHL.The patient experienced failure of eight lines of therapy,including multiple cycles of chemotherapy,PD-1 blockade,and anti-CD47 antibody therapy.Contrast-enhanced CT showed that the tumors of the chest and abdomen significantly shrunk or disappeared after three cycles of treatment with decitabine plus tislelizumab.The patient had been followed for 11.5 mo until March 2,2021,and no progressive enlargement of the tumor was observed.CONCLUSION The strategy of combining low-dose decitabine with tislelizumab could reverse the resistance to PD-1 inhibitors in patients with heavily pretreated relapsed/refractory cHL.The therapeutic effect of this strategy needs to be further assessed.

Promoter hypomethylation and reactivation of MAGE-A1 and MAGE-A3 genes in colorectal cancer cell lines and cancer tissues

AIM： To verify the expression and methylation status of the MAGE-A1 and MAGE-A3 genes in colorectal cancer tissues and cancer cell lines. METHODS： We evaluated promoter demethylation status of the MAGE-A1 and MAGE-A3 genes by RT-PCR analysis and methylation-specific PCR （MS-PCR）, as well as sequencing analysis, after sodium bisulfite modification in 32 colorectal cancer cell lines and 87 cancer tissues. RESULTS： Of the 32 cell lines, MAGE-A1 and MAGE-A3 expressions were observed in 59% and 66%, respectively. Subsequent to sodium bisulfite modification and MSPCR analysis, the promoter hypomethylation of MAGE-A1 and MAGE-A3 was confirmed in both at 81% each. Promoter hypomethylation of MAGE-A1 and MAGE-A3 in colorectal cancer tissues was observed in 43% and 77%, respectively. Hypomethylation of MAGE-A1 and MAGE-A3 genes in corresponding normal tissues were observed in 2% and 6%, respectively. CONCLUSION： The promoter hypomethylation of MAGE genes up-regulates its expression in colorectal carcinomas as well as in gastric cancers and might play a significant role in the development and progression of human colorectal carcinomas.

LncRNA DPP10-AS1 promotes malignant processes through epigenetically activating its cognate gene DPP10 and predicts poor prognosis in lung cancer patients

Objective:The purpose of this study was to explore the function and gene expression regulation of the newly identified lnc RNA DPP10-AS1 in lung cancer,and its potential value as a prognostic biomarker.Methods:q RT-PCR and Western blot were conducted to detect the expression of DDP10-AS1 and DPP10 in lung cancer cell lines and tissues.The effects of DDP10-AS1 on DPP10 expression,cell growth,invasion,apoptosis,and in vivo tumor growth were investigated in lung cancer cells by Western blot,rescue experiments,colony formation,flow cytometry,and xenograft animal experiments.Results:The novel antisense lnc RNA DPP10-AS1 was found to be highly expressed in cancer tissues(P<0.0001),and its upregulation predicted poor prognosis in patients with lung cancer(P=0.0025).Notably,DPP10-AS1 promoted lung cancer cell growth,colony formation,and cell cycle progression,and repressed apoptosis in lung cancer cells by upregulating DPP10 expression.Additionally,DPP10-AS1 facilitated lung tumor growth via upregulation of DPP10 protein in a xenograft mouse model.Importantly,DPP10-AS1 positively regulated DPP10 gene expression,and both were coordinately upregulated in lung cancer tissues.Mechanically,DPP10-AS1 was found to associate with DPP10 m RNA but did not enhance DPP10 m RNA stability.Hypomethylation of DPP10-AS1 and DPP10 contributed to their coordinate upregulation in lung cancer.Conclusions:These findings indicated that the upregulation of the antisense lnc RNA DPP10-AS1 promotes lung cancer malignant processes and facilitates tumorigenesis by epigenetically regulating its cognate sense gene DPP10.DPP10-AS1 may serve as a candidate prognostic biomarker and a potential therapeutic target in lung cancer.

Alteration of oncogenic IGF-II gene methylation status associates with hepatocyte malignant transformation

Background: Oncogenic insulin-like growth factor-II(IGF-II) is overexpressed in hepatocellular carcinoma(HCC). The present study aimed to analyze the dynamic alteration of IGF-II CpG site methylation status and its molecular mechanism in HCC progression. Methods: IGF-II alterations were observed in rat hepatocarcinogenesis models induced by 2-acetylaminofluorene. Liver IGF-II expression was compared by immunohistochemistry or tissue IGF-II specific concentration(nmol/mg protein). Status of human IGF-II promoter 3(P3) or rat IGF-II P2 CpG site methylation was amplified by methylation-specific polymerase chain reaction(MSP). Serum IGF-II levels were quantitatively detected by an enzyme-linked immunosorbent assay. Results: The levels of hepatic IGF-II expression were significantly elevated in the HCC group( P < 0.001). The unmethylation rate of IGF-II P3 CpG sites was 100% in the HCC-, 52.5% in the paracancerous-, and none(0%) in the distal noncancerous-tissues. Abnormal IGF-II expression was related to differentiation degree, tumor invasion, and positive HBV-DNA(all P < 0.001), with a negative correlation between P3 methylation degree and IGF-II expression. There was a positive correlation between liver IGF-II specific concentration and circulating IGF-II level( r = 0.97, P < 0.001). Significantly negative correlation was found between IGF-II P2 CpG site methylation and circulating IGF-II( r s =-0.89, P < 0.001) or liver IGF-II level( r s =-0.84, P < 0.001). Conclusions: The increase of serum IGF-II and the alteration of oncogenic gene IGF-II methylation may be biomarkers for HCC diagnosis and DNA methylation may be the therapeutic target of HCC.

Dietary betaine activates hepatic VTGⅡexpression in laying hens associated with hypomethylation of GR gene promoter and enhanced GR expression

Background: Vitellogenin(VTG) is a precursor of egg yolk proteins synthesized within the liver of oviparous vertebrates. Betaine is an important methyl donor that is reported to improve egg production of laying hens with an unclear mechanism. In the present study, we fed betaine-supplemented diet(0.5%) to laying hens for 4 wk and investigated its effect on VTGII expression in the liver.Results: Betaine did not affect chicken weight, but significantly(P < 0.05) increased egg laying rate accompanied with a significant(P < 0.05) increase in hepatic concentration and plasma level of VTGI. Plasma estrogen level did not change,but the hepatic expression of estrogen receptor α(ERα) mR NA was significantly(P < 0.05) up-regulated. Betaine did not affect the protein content of ERα, but significantly(P < 0.05) increased hepatic expression of glucocorticoid receptor(GR)at both mR NA and protein levels. Also, ERα/GR interaction tended to be enhanced in the liver nuclear lysates of betainesupplemented hens as determined by co-immunoprecipitation. Furthermore, dietary betaine supplementation significantly increased(P < 0.05) the hepatic expression of methyl-transfer enzymes, such as BHMT, GNMT, and DNMT1,which was associated with higher SAM/SAH ratio and hypomethylation of GR promoter regions.Conclusions: Betaine activates hepatic VTGII expression in association with modified DNA methylation of GR gene promoter, GR expression and ERα/GR interaction. Activation of hepatic VTGII expression may contribute, at least partly, to improved egg production in betaine-supplemented hens.

Global hypomethylation in hepatocellular carcinoma and its relationship to aflatoxin B_1 exposure

AIM:To determine global DNA methylation in paired hepatocellular carcinoma(HCC) samples using several different assays and explore the correlations between hypomethylation and clinical parameters and biomarkers,including that of aflatoxin B 1 exposure.METHODS:Using the radio labeled methyl acceptance assay as a measure of global hypomethylation,as well as two repetitive elements,including satellite 2(Sat2) by MethyLight and long interspersed nucleotide elements(LINE1),by pyrosequencing.RESULTS:By all three assays,mean methylation levels in tumor tissues were significantly lower than that in adjacent tissues.Methyl acceptance assay log(mean ± SD) disintegrations/min/ng DNA are 70.0 ± 54.8 and 32.4 ± 15.6,respectively,P = 0.040;percent methylation of Sat2 42.2 ± 55.1 and 117.9 ± 88.8,respectively,P < 0.0001 and percent methylation LINE1 48.6 ± 14.8 and 71.7 ± 1.4,respectively,P < 0.0001.Aflatoxin B 1 albumin(AFB 1-Alb) adducts,a measure of exposure to this dietary carcinogen,were inversely correlated with LINE1 methylation(r =-0.36,P = 0.034).CONCLUSION:Consistent hypomethylation in tumor compared to adjacent tissue was found by the three different methods.AFB 1 exposure is associated with DNA global hypomethylation,suggesting that chemical carcinogens may influence epigenetic changes in humans.

Promoter hypomethylation regulates CD133 expression in human gliomas

Brain tumor-initiating cells （BTICs） have been enriched using antibodies against the cell surface protein CD133; however, the biological relevance and the regulatory mechanism of CD133 expression in human gliomas are not yet understood. In this study, we initially demonstrated that CD133 was overexpressed in high-grade human glioblastomas where CD133-positive cells were focally observed as a micro-cluster. In addition, CD133 transcripts with exon 1A, 1B, or 1C were predominantly expressed in glioblastomas. To elucidate the mechanism regulating this aberrant expression of CD133, three proximal promoters （P1, P2, and P3） containing a CpG island were isolated. In U251MG and T98G glioblastoma cells, the P1 region flanking exon 1A exhibited the highest activity among the three promoters, and this activity was significantly inactivated by in vitro methylation. After treatment with the demethylating agent 5-azacytidine and/or the histone deacetylase inhibitor valproic acid, the expression level of CD133 mRNA was significantly restored in glioma cells. Importantly, hypomethylation of CpG sites within the P1, P2, and P3 regions was observed by bisulfite sequencing in human glioblastoma tissues with abundant CD133 mRNA. Taken together, our results indicate that DNA hypomethylation is an important determinant of CD133 expression in glioblastomas, and this epigenetic event may be associated with the development of BTICs expressing CD133.

Phase Ⅲ Clinical Trials of the Cell Differentiation Agent-2 （CDA-2）： Therapeutic Efficacy on Breast Cancer, Non-Small Cell Lung Cancer and Primary Hepatoma

OBJECTIVE The objective of this study was to explore the effect of CDA-2, a selective inhibitor of abnormal methylation enzymes in cancer cells, on the therapeutic efficacy of cytotoxic chemotherapy. METHODS Advanced cancer patients, all of whom had previously undergone chemotherapy, were randomly divided into 2 groups, one receiving chemotherapy only as the control group, and the other receiving CDA-2 in addition to chemotherapy as the combination group. The therapeutic efficacies and the toxic maniestations of the 2 groups were compared based on the WHO criteria. RESULTS Of 454 cancer patients enrolled in phase Ⅲ clinical trials of CDA-2, 80, 188, and 186 were breast cancer, NSCLC, and primary hepatoma patients, respectively. Among them 378 patients completed treatments according to the protocols. The results showed that the overall effective rate of the combination group was 2.6 fold that of the control group, 4.8 fold in the case of breast cancer, 2.3 fold in the case of primary hepatoma, and 2.2 fold in the case of NSCLC. Surprisingly, the combination therapy appeared to work better for stage Ⅳ than stage Ⅲ patients. CDA-2 did not contribute additional toxicity. On the contrary, it reduced toxic manifestations of chemotherapy, particularly regarding white blood cells, nausea and vomiting. CONCLUSION Modulation of abnormal methylation enzymes by CDA-2 is definitely helpful to supplement chemotherapy. It significantly increased the therapeutic efficacy and reduced the toxic manifestation of cytotoxic chemotherapy on breast cancer and NSCLC.

Eagles report:Developing cancer biomarkers from genomewide DNA methylation analyses

Analyses of DNA methylation in human cancers have identified hypermethylation of individual genes and diminished methylation at repeat elements as common alterations,and have thereby provided important mechanistic insights into cancer biology as well as biomarkers for cancer detection,prognosis and prediction of therapy responses.The techniques available in the past were best suited for investigations of individual candidate genes and sequences,whereas recently developed high-throughput techniques promise to generate unbiased and comprehensive surveys of DNA methylation states across entire genomes.In this minireview we give a short overview of established and novel techniques and outline some major questions that can now be addressed to develop further cancer biomarkers and therapies based on DNA methylation.

Regulation of P1-450 Gene Expression by Dimethylbenzanthracene in Human Lung Tumor Cells in Culture

Polycyclic aromatic hydrocarbons(PAHs),dimethyl beazanthracene(DMBA)and benzo-(a)-pyrene(BaP),stimulate the expression of the P1-450 gene in human lung tumor cells(ChaGo)in culture.A concentration-and time-dependent increase in the level of P1-450 specific mRNA sequences hasbeen observed in ChaGo cells treated with sublethal concentrations of DMBA.Results presentedsuggest that the parent compound causes the induction of P1-450 gene expression.The methylationpattern of the internal“-C-” residues of the “-CCGG-” sequence has been studied in a stretch ofabout 8000 base pairs(bp)of DNA sequence in and around the P1-450 gene in the control andDMBA-treated ChaGo cells.A comparative Southern blot analysis of the Msp Ⅰ/Hpa Ⅱ digestedDNA of the control and DMBA-treated ChaGo cells followed by hybridization with ^(32)P-labelledregion-specific probes,revealed that i)the internal “-C-” residues of the “-CCGG-” sequences ofdifferent regions of P1-450 gene were methylated to different degrees;ii)DMBA treatment of thecells induced hypomethylation of only the 5' end “-CCGG-” sequences of the gene;and iii)themethylation patterns of “-CCGG-” sequences of most of the coding region and of the 3' end regionof P1-450 gene were not affected by such DMBA treatment.

Pre-transplantation cytoreduction does not benefit advancedmyelodysplastic syndrome patients after myeloablative transplantation with grafts from family donors

Background:The role of pre-hematopoietic stem cell transplantation(HSCT)cytoreduction with either induction chemotherapy(IC)or hypomethylating agents(HMAs)in treating advanced myelodysplastic syndrome(MDS)remains debatable.We aimed to evaluate pre-HSCT strategies by comparing the endpoints related to disease control between advanced MDS patients with pre-HSCT cytoreduction and those with best supportive care.Methods:We described 228 consecutive advanced MDS patients who received HSCT from a haploidentical donor(HID,n=162)or matched related donor(MSD,n=66)with uniform myeloablative conditioning regimens between January 2015 and December 2018.Of these 228 patients,131(57.5%)were treated exclusively with pre-HSCT best supportive care(BSC),49(22.5%)were given HMA,and 48(21.1%)received both IC and HMA.Propensity score-matching analysis,multivariate analyses,and subgroup analyses were performed to elucidate the impact of pre-HSCT strategies on transplant outcomes.Results:The 3-year relapse-free survival(RFS)rates were 78.2% and 70.0% for the BSC and cytoreduction cohorts(P=0.189)and were 78.2%,66.7%,and 73.2% for the BSC,HMA,and HMA+IC groups,respectively(P=0.269).A propensity score-matching analysis confirmed that the 3-year RFS rates were 81.9%,87.5%,and 66.9% for BSC,cytoreduction complete remission(CR),and cytoreduction non-CRgroups,respectively(P=0.051).Multivariate analyses demonstrated that pre-HSCT cytoreduction,older patient age,monosomal karyotype,and interval between diagnosis and HSCT were poor prognostic factors for RFS.In the subgroup analyses,BSC was associated with longer RFS compared to cytoreduction among the younger patients,those with international prognostic scoring system intermediate-2/high risk at diagnosis,and those with intermediate/poor cytogenetics.Conclusions:Different pre-HSCT therapies did not yield discrepant post-HSCT outcomes.No benefit in terms of post-HSCT outcomes were correlated with pre-HSCT cytoreduction in advanced MDS even for cytoreduction CR patients.Early referral to HSCT is essential for advanced MDS patients.

The evolving landscape in the therapy of acute myeloid leukemia

Acute myeloid leukemia(AML)is a heterogeneous clonal disorder of myeloid precursors arrested in their matura-tion,creating a diverse disease entity with a wide range of responses to historically standard treatment approaches.While signifi cant progress has been made in character-izing and individualizing the disease at diagnosis to op-timally inform those affected,progress in treatment to reduce relapse and induce remission has been limited thus far.In addition to a brief summary of the factors that shape prognostication at diagnosis,this review attempts to expand on the current therapies under investigation that have shown promise in treating AML,including hy-pomethylating agents,gemtuzumab ozogamicin,FLT3 ty-rosine kinase inhibitors,antisense oligonucleotides,and other novel therapies,including aurora kinases,mTOR and PI3 kinase inhibitors,PIM kinase inhibitors,HDAC inhibitors,and IDH targeted therapies.With these,and undoubtedly many others in the future,it is the hope that by combining more accurate prognostication with more effective therapies,patients will begin to have a different,and more complete,outlook on their disease that allows for safer and more successful treatment strategies.

Venetoclax resistance:mechanistic insights and future strategies

Acute myeloid leukemia(AML)is historically associated with poor prognosis,especially in older AML patients unfit for intensive chemotherapy.The development of Venetoclax,a potent oral BH3(BCL-2 homology domain 3)mimetic,has transformed the AML treatment.However,the short duration of response and development of resistance remain major concerns.Understanding mechanisms of resistance is pivotal to devising new strategies and designing rational drug combination regimens.In this review,we will provide a comprehensive summary of the known mechanisms of resistance to Venetoclax and discuss Venetoclax-based combination therapies.Key contributing factors to Venetoclax resistance include dependencies on alternative anti-apoptotic BCL-2 family proteins and selection of the activating kinase mutations.Mutational landscape governing response to Venetoclax and strategic approaches developed considering current knowledge of mechanisms of resistance will be addressed.

Association between Long Interspersed Nuclear Element-1 Methylation and Relative Telomere Length in Wilms Tumor

Background： DNA hypomethylation of long interspersed nuclear elements- 1 （LINEs- 1 ） occurs during carcinogenesis, whereas intbmaation addressing LINE-1 methylation in Wilms tumor （WT） is limited. The main purpose of our study was to quantity, LINE-1 methylation levels and evaluate their relationship with relative telomere length （TL） in WT. Methods： We investigated LINE-1 methylation and relative TL using bisulfite-polymerase chain reaction （PCR） pyrosequencing and quantitative PCR, respectively, in 20 WT tissues, 10 normal kidney tissues and a WT cell line. Significant changes were analyzed by t-tests. Results： LINE-1 methylation levels were significantly lower （P 〈 0.05） and relative TLs were sigmificantly shorter （P 〈 0.05） in WT compared with normal kidney. There was a significant positive relationship between LINE- 1 methylation and relative TL in WT （r = 0.671, P = 0.001 ）. LINE- 1 Methylation levels were significantly associated with global DNA methylation （r = 0.332, P 〈 0.01 ）. In addition, relative TL was shortened and LINE- 1 methylation was decreased in a WT cell line treated with the hypomethylating agent 5-aza-2＇-deoxycytidine compared with untreated WT cell line. Conclusion： These results suggest that LINE-1 hypomethylation is common and may be linked to telomere shortening in WT.

Association of hypomethylation of LINE-1 repetitive element in blood leukocyte DNA with an increased risk of hepatocellular carcinoma

Global DNA hypomethylation has been associated with increased risk for cancers of the colorectum,bladder,breast,head and neck,and testicular germ cells.The aim of this study was to examine whether global hypomethylation in blood leukocyte DNA is associated with the risk of hepatocellular carcinoma (HCC).A total of 315 HCC cases and 356 age-,sex-and HBsAg status-matched controls were included.Global methylation in blood leukocyte DNA was estimated by analyzing long interspersed element-1 (LINE-1) repeats using bisulfite-polymerase chain reaction (PCR) and pyrosequencing.We observed that the median methylation level in HCC cases (percentage of 5-methylcytosine (5mC)=77.7%) was significantly lower than that in controls (79.5% 5mC) (P=0.004,Wilcoxon rank-sum test).The odds ratios (ORs) of HCC for individuals in the third,second,and first (lowest) quartiles of LINE-1 methylation were 1.1 (95% confidence interval (CI) 0.7-1.8),1.4 (95% CI 0.8-2.2),and 2.6 (95% CI 1.7-4.1) (P for trend <0.001),respectively,compared to individuals in the fourth (highest) quartile.A 1.9-fold (95% CI 1.4-2.6) increased risk of HCC was observed among individuals with LINE-1 methylation below the median compared to individuals with higher (>median) LINE-1 methylation.Our results demonstrate for the first time that individuals with global hypomethylation measured in LINE-1 repeats in blood leukocyte DNA have an increased risk for HCC.Our data provide the evidence that global hypomethylation detected in the easily obtainable DNA source of blood leukocytes may help identify individuals at risk of HCC.