miR-1250-5p is a novel tumor suppressive intronic miRNA hypermethylated in non-Hodgkin's lymphoma: novel targets with impact on ERK signaling and cell migration.

BACKGROUND: miR-1250 is localised to the second intron of AATK at chromosome 17q25. As a CpG island is present at the putative promoter region of its host gene, AATK, we postulated that the intronic miR-1250-5p is a tumor suppressor miRNA co-regulated with its host gene, AATK, by promoter DNA methylation in non-Hodgkin's lymphoma (NHL). METHODS: AATK/miR-1250 methylation was studied in healthy controls, including ten normal peripheral blood buffy coats and eleven normal tonsils, ten lymphoma cell lines, and 120 primary lymphoma samples by methylation-specific PCR (MSP). The expression of miR-1250-5p and AATK was investigated by quantitative real-time PCR. Tumor suppressor properties of miR-1250-5p were demonstrated by over-expression of precursor miR-1250-5p in lymphoma cells. The target of miR-1250-5p was verified by luciferase reporter assay. RESULTS: AATK/miR-1250 methylation was absent in healthy peripheral blood and tonsils, but detected in five (50%) NHL cell lines. AATK/miR-1250 methylation correlated with repression of miR-1250-5p and AATK in NHL cell lines. In completely methylated SU-DHL-6 and SUP-T1 cells, treatment with 5-AzadC led to promoter demethylation and re-expression of both miR-1250-5p and AATK. In primary lymphoma samples, AATK/miR-1250 was frequently methylated in B-cell lymphoma (n = 41, 44.09%) and T-cell lymphoma (n = 9, 33.33%) with a comparable frequency (P = 0.318). In SU-DHL-6 and SU-DHL-1 cells, restoration of miR-1250-5p resulted in decreased cellular proliferation by MTS assay, increased cell death by trypan blue staining and enhanced apoptosis by annexin V-PI assay. Moreover, MAPK1 and WDR1 were verified as direct targets of miR-1250-5p by luciferase assay. In 39 primary NHLs, miR-1250-5p expression was shown to be inversely correlated with each of MAPK1 (P = 0.05) and WDR1 (P = 0.031) by qRT-PCR. Finally, in SU-DHL-1 cells, overexpression of miR-1250-5p led to repression of MAPK1 and WDR1 at both transcript and protein levels, with downregulation of phospho-ERK2 by Western-blotting and inhibition of SDF-1-dependent cell migration by transwell assay. CONCLUSIONS: miR-1250-5p is a novel tumor suppressive intronic miRNA co-regulated and silenced by promoter DNA methylation of its host gene AATK in NHL. MAPK1 and WDR1 are novel miR-1250-5p direct targets rendering inhibition of MAPK/ERK signaling and SDF-1-dependent cell migration, hence implicated in survival and dissemination of lymphoma. Video Abstract.

Epigenetic silencing of long non-coding RNA BM742401 in multiple myeloma: impact on prognosis and myeloma dissemination.

BACKGROUND: Long non-coding RNA (lncRNA) BM742401 is a tumor suppressor in gastric cancer and chronic lymphocytic leukemia. As the promoter and coding region of BM742401 are fully embedded in a CpG island, we hypothesized that BM742401 is a tumor suppressor lncRNA epigenetically silenced by promoter DNA methylation in multiple myeloma. METHODS: Methylation-specific PCR and quantitative bisulfite pyrosequencing were performed to detect the methylation of BM742401 in normal plasma cells, myeloma cell lines and primary myeloma samples. The expression of BM742401 was measured by qRT-PCR. The function of BM742401 in multiple myeloma cells was analyzed by lentivirus transduction followed by migration assay. RESULTS: BM742401 methylation was detected in 10 (66.7%) myeloma cell lines but not normal plasma cells, and inversely correlated with expression of BM742401. In primary samples, BM742401 methylation was detected in 3 (12.5%) monoclonal gammopathy of undetermined significance, 9 (15.8%) myeloma at diagnosis and 8 (17.0%) myeloma at relapse/progression. Moreover, BM742401 methylation at diagnosis was associated with inferior overall survival (median OS: 25 vs. 39 months; P = 0.0496). In myeloma cell line JJN-3, stable overexpression of BM742401 by lentivirus transduction resulted in reduced cell migration (P = 0.0001) but not impacting cell death or proliferation. CONCLUSIONS: This is the first report of tumor-specific methylation-mediated silencing of BM742401 in myeloma, which is likely an early event in myelomagenesis with adverse impact on overall survival. Moreover, BM742401 is a tumor suppressor lncRNA by inhibiting myeloma cell migration, hence implicated in myeloma plasma cell homing, metastasis and disease progression.

Low-dose pembrolizumab and nivolumab were efficacious and safe in relapsed and refractory classical Hodgkin lymphoma: Experience in a resource-constrained setting.

The efficacy and safety of low-dose anti-PD1 antibodies in relapsed/refractory classical Hodgkin lymphoma (cHL) require confirmation. Pembrolizumab (100 mg every 3 weeks, Q3W) or nivolumab (40 mg Q2W) were administered to patients with relapsed/refractory cHL. In the pembrolizumab cohort (N = 11), who had failed a median of three (1-6) therapies (brentuximab vedotin [BV]: 91%; autologous hematopoietic stem cell transplantation [auto-HSCT]: 18%), the overall response rate (ORR) by positron emission tomography-computed tomography was 100% (metabolic complete response [mCR]: 73%; partial response [PR]: 27%). Median cumulative dose for achieving best response was 400 (300-800) mg. Median progression-free survival (PFS) was 35 months. Median overall survival (OS) was not reached. Adverse events (AEs) of grade 1-2 were observed in three patients. In the nivolumab cohort (N = 6), who had failed a median of three (2-6) therapies (BV: 50%; auto-HSCT: 17%; allogeneic HSCT: 34%), the ORR was 100% (mCR: 67%; PR: 17%; indeterminate response: 17%). Median cumulative dose for achieving best response was 160 (160-360) mg. Median PFS was 33 months. Median OS was not reached. AEs of grade 1-2 were observed in four patients, two of whom had pre-existing autoimmune conditions. Five patients with Epstein-Barr virus (EBV) positive Reed-Sternberg cells underwent monitoring of plasma EBV DNA, which became negative in four mCR patients but remained positive in one PR patient who died ultimately from refractory lymphoma. Low-dose pembrolizumab and nivolumab were highly efficacious and safe in relapsed/refractory cHL. These observations have significant financial implications in resource-constrained settings.

Survival differences in multiple myeloma in Latin America and Asia: a comparison involving 3664 patients from regional registries.

In previous observational studies, we have separately characterized patients with multiple myeloma (MM) both from Latin America (LA) and from Asia. Here, we analyze these two datasets jointly, in order to assess the overall survival (OS) in these two world regions. Data were available from 3664 patients (1968 from LA and 1696 from Asia); all of whom diagnosed between 1998 and 2007. Approximately, 26% of patients in both world regions underwent transplantation. OS (from diagnosis of MM) was explored with Kaplan-Meier analyses and Cox proportional hazards models. Patients from LA were significantly younger and had hypercalcemia more often than Asian patients, who in turn had higher proportions of anemia and International Staging System (ISS) stage III disease. The median OS was 56 months in LA, and 47 months in Asia (hazard ratio [HR] = 0.83; 95% confidence interval [CI], 0.76 to 0.91; P < 0.001). In multivariable analysis, age, ISS stage III, anemia, hypercalcemia, and world region remained significantly associated with OS (P < 0.001 for all covariates). These results were largely driven by patients not undergoing transplantation, as no difference in OS emerged between the two world regions in univariable or multivariable analysis for transplanted patients. Despite adverse prognostic features differentially favoring each region, and adjusting for such differences, we found an OS advantage for patients from LA, in comparison with contemporaneous patients from Asia. Whether this is due to different biological features, differences in access to novel agents (especially thalidomide in earlier periods of the study), unmeasured confounders, or the play of chance, remain unknown.

Molecular detection of minimal residual disease in multiple myeloma.

Despite the significantly higher complete remission rates and improved survival achieved in the last decade, multiple myeloma (MM) patients continue to relapse due to persistence of minimal residual disease (MRD). Generally, MRD refers to persistence of low levels of disease in the order of one tumour cell in ≥105 normal cells. Currently, molecular and immunophenotypic techniques are employed for MRD detection. This review focuses on MRD detection by molecular techniques, including allele-specific oligonucleotide polymerase chain reaction (ASO-PCR), next-generation sequencing (NGS) and digital PCR (dPCR), in addition to a brief description of, and comparison with, multiparameter flow cytometry. The basic principles, technical advantages and limitations, and the clinical impact of all three molecular techniques are reviewed and compared. They all have a sensitivity of at least 10-5 , among which ASO real-time quantitative PCR is the most well-standardized, and NGS carries the highest sensitivity and applicability, while dPCR is still under investigation. Furthermore, molecular MRD negativity is a favourable prognostic factor for survival of patients with MM. However, several challenges inherent to molecular detection of MRD still remain to be overcome, particularly false negativity and failure to detect extramedullary disease. Finally, detection of MRD from peripheral blood remains challenging.

RANKL expression in myeloma cells is regulated by a network involving RANKL promoter methylation, DNMT1, microRNA and TNFα in the microenvironment.

We studied the regulation of RANKL expression in myeloma by promoter DNA methylation. Methylation-specific polymerase chain reaction showed complete methylation of RANKL promoter in WL-2 myeloma cells but partial methylation in eight other lines. 5-AzadC treatment of WL-2 cells led to demethylation and re-expression of RANKL. Transwell and contact co-culture of WL-2 cells with normal bone marrow-derived mesenchymal stromal cells (BMSCs) resulted in comparable repression of DNA methyltransferase-1 (DNMT1) and re-expression of RANKL in WL-2 cells. Moreover, treatment of WL-2 cells with TNFα led to repression of DNMT1 and re-expression of RANKL in association with upregulation of miR-140-3p and miR-126, which are partially offset by addition of anti-TNFα antibody to transwell-coculture of WL2 with BMSC. Taken together, our results showed that TNFα in the marrow microenvironment led to RANKL demethylation and re-expression in myeloma cells through DNMT1 repression and upregulation of miR-126-3p and miR-140, both known to repress DNMT1 translation.

Epigenetic silencing of a long non-coding RNA KIAA0495 in multiple myeloma.

In multiple myeloma, a long non-coding RNA, KIAA0495 (alias PDAM/TP73-AS1), had been found progressively downregulated from normal plasma cell to benign monoclonal gammopathy of undetermined significance to symptomatic myeloma. Herein, by methylation-specific PCR, the putative KIAA0495 promoter was found unmethylated in all healthy controls (N = 14) but methylated in 50 % of myeloma cell lines (N = 10). KIAA0495 methylation was shown inversely correlated with KIAA0495 expression. However, KIAA0495 methylation was detected in none of both primary myeloma samples at diagnosis (N = 61) and at relapse/progression (N = 16). Collectively, despite frequently methylated in cell lines, KIAA0495 methylation appeared unimportant in the pathogenesis or progression of myeloma.

LDH is an adverse prognostic factor independent of ISS in transplant-eligible myeloma patients receiving bortezomib-based induction regimens.

BACKGROUND: Serum lactate dehydrogenase (LDH) has been an adverse prognostic factor for myeloma but does not feature in the International Staging System (ISS). We examined whether elevated serum LDH at diagnosis remains an adverse risk factor independent of ISS for survivals transplant-eligible myeloma patients receiving early/frontline bortezomib-based induction, followed by autologous stem cell transplantation (ASCT). PATIENTS: Seventy-seven transplant-eligible Chinese patients received three induction regimens [staged approach (N = 25), PAD (N = 19), VTD (N = 33)], followed by ASCT and thalidomide maintenance. RESULTS: Five-year overall (OS) and event-free (EFS) survivals were 66.4% and 36.2%. There was no difference in demographics, complete remission/near complete remission (CR/nCR rates postinduction or ASCT, and survivals among patients induced by the three induction regimens. Elevated LDH was associated with male gender (P = 0.006), ISS III (P = 0.042) and serum ß2-microglobulin (P = 0.040). Univariate analysis showed that elevated LDH, ISS III, high ß2-microglobulin, and failure to attain CR/nCR post-ACST were risk factors adversely impacting both OS and EFS. Multivariate analysis showed that elevated LDH was the only factor impacting both OS (P = 0.007) and EFS (P = 0.008). CONCLUSION: In this uniformly treated cohort of transplant-eligible myeloma patients, elevated serum LDH is an adverse risk factor independent of ISS for both OS and EFS. Bortezomib-based induction/ASCT regimen had not abolished the adverse impact of elevated LDH.

Epigenetic inactivation of mir-34b/c in addition to mir-34a and DAPK1 in chronic lymphocytic leukemia.

BACKGROUND: TP53 mutation/deletion is uncommon in chronic lymphocytic leukemia (CLL). We postulated that components of TP53-centered tumor suppressor network, miR-34b/c, in addition to DAPK1 and miR-34a might be inactivated by DNA hypermethylation. Moreover, we tested if miR-34b/c methylation might correlate with miR-203 or miR-124-1 methylation in CLL. METHODS: miR-34b/c, miR-34a and DAPK1 methylation was studied in 11 normal controls, 7 CLL cell lines, and 78 diagnostic CLL samples by methylation-specific polymerase chain reaction. MEC-1 cells were treated with 5-Aza-2'-deoxycytidine for reversal of methylation-associated miRNA silencing. Tumor suppressor properties of miR-34b were demonstrated by over-expression of precursor miR-34b in MEC-1 cells. RESULTS: miR-34b/c promoter was unmethylated in normal controls, but completely methylated in 4 CLL cell lines. miR-34b/c expression was inversely correlated with miR-34b/c methylation. Different MSP statuses of miR-34b/c, including complete methylation and complete unmethylation, were verified by quantitative bisulfite pyrosequencing. 5-Aza-2'-deoxycytidine treatment resulted in promoter demethylation and miR-34b re-expression in MEC1 cells. Moreover, over-expression of miR-34b resulted in inhibition of cellular proliferation and increased cell death. In primary CLL samples, miR-34a, miR-34b/c and DAPK1 methylation was detected in 2.6%, 17.9% and 34.6% of patients at diagnosis respectively. Furthermore, 39.7%, 3.8% and 2.6% patients had methylation of one, two or all three genes respectively. Overall, 46.2% patients had methylation of at least one of these three genes. Besides, miR-34b/c methylation was associated with methylation of miR-34a (P = 0.03) and miR-203 (P = 0.012) in CLL. CONCLUSIONS: Taken together, miR-34b/c is a tumor suppressor miRNA frequently methylated, and hence silenced in CLL. Together with DAPK1 methylation, miR-34b/c methylation is implicated in the disruption of the TP53-centered tumor suppressor network. Moreover, the association of miRNA methylation warrants further study.

SMILE for natural killer/T-cell lymphoma: analysis of safety and efficacy from the Asia Lymphoma Study Group.

Natural killer/T-cell lymphoma is rare and aggressive, with poor outcome. Optimal treatment remains unclear. A novel regimen dexamethasone, methotrexate, ifosfamide, l-asparaginase, and etoposide (SMILE) showed promise in phase 1/2 studies with restrictive recruitment criteria. To define the general applicability of SMILE, 43 newly diagnosed and 44 relapsed/refractory patients (nasal, N = 60, nonnasal, N = 21; disseminated, N = 6; male, N = 59; female, N = 28) at a median age of 51 years (23-83 years) were treated. Poor-risk factors included stage III/IV disease (56%), international prognostic index of 3 to 5 (43%), and Korean prognostic scores of 3 to 4 (41%). A median of 3 (0-6; total = 315) courses of SMILE were administered. Significant toxicities included grade 3/4 neutropenia (N = 57; 5 sepsis-related deaths); grade 3/4 thrombocytopenia (N = 36); and nephrotoxicity (N = 15; 1 acute renal failure and death). Interim analysis after 2 to 3 cycles showed complete remission rate of 56%, partial remission rate of 22%, giving an overall response rate of 78%. On treatment completion, the overall-response rate became 81% (complete remission = 66%, partial remission = 15%). Response rates were similar for newly diagnosed or relapsed/refractory patients. At a median follow-up of 31 months (1-84 months), the 5-year overall survival was 50% and 4-year disease-free-survival was 64%. Multivariate analysis showed that international prognostic index was the most significant factor impacting on outcome and survivals.

Unsustained complete response of less than 24 months after autologous stem cell transplantation predicts aggressive myeloma with short survival.

Complete response (CR) predicts superior survivals in myeloma. To define the impact of duration of CR posttransplantation on survivals, 71 myeloma patients, who underwent an intended early (a staged approach) or frontline use of bortezomib-based induction, followed by autologous stem cell transplantation (ASCT) were studied. Achievement of CR was assessed every 4-weekly until maximal response after ASCT and then 6-weekly thereafter. All patients had follow-up time of ≥24 months from time of best response, of whom 27 failed to attain CR (non-CR) whereas 44 achieved CR. At 12, 18 and 24 months post-ASCT, 3 (4.2%), 6 (8.4%) and 11 (15.4%) patients lost CR, respectively, with maximal survival difference observed in the group with CR durations of ≥24 or <24 months. Patients with unsustained CR had survival inferior to those never achieving CR (p = 0.05). Unsustained CR of <24 months was associated with international staging system stage III (p = 0.007) and shorter postrelapse survival (p < 0.001). Both overall survival and event-free survival were superior in myeloma patients with CR of ≥24 months (p < 0.001). In multivariate analysis, international staging system stage I/II, CR/nCR post-ASCT and CR duration of ≥24 months remained favourable prognostic factors for both overall survival and event-free survival. In conclusion, CR of <24 months is an independent adverse risk factor for survival with a short postrelapse survival.

Breakthrough invasive fungal diseases during echinocandin treatment in high-risk hospitalized hematologic patients.

The frequency of breakthrough invasive fungal diseases (IFDs) during echinocandin therapy is unclear. We retrospectively analyzed 534 hematologic patients treated with echinocandin (caspofungin, N = 55; micafungin, N = 306; anidulafungin, N = 173). Four proven IFDs were found, caused by Candida parapsilosis (N = 2), C. parapsilosis and Candida glabrata (N = 1), and Fusarium species (N = 1). Four cases of possible IFDs were observed, all showing pulmonary infection. One case showed features suggestive of hepatosplenic candidiasis. Six of these eight cases had previously received the purine analog clofarabine. Breakthrough IFD during echinocandin treatment occurred infrequently (1.5 %), caused predominantly by Candida species. Clofarabine usage was an important risk factor.

Clinical profiles of multiple myeloma in Asia-An Asian Myeloma Network study.

The incidence of multiple myeloma (MM) is known to be variable according to ethnicity. However, the differences in clinical characteristics between ethnic groups are not well-defined. In Asian countries, although the incidence of MM has been lower than that of Western countries, there is growing evidence that MM is increasing rapidly. The Asian Myeloma Network decided to initiate the first multinational project to describe the clinical characteristics of MM and the clinical practices in Asia. Data were retrospectively collected from 23 centers in 7 countries and regions. The clinical characteristics at diagnosis, survival rates and initial treatment of 3,405 symptomatic MM patients were described. Median age was 62 years (range, 19-106), with 55.6% of being male. Median overall survival (OS) was 47 months (95% CI 44.0-50.0). Stem cell transplantation was performed in 666 patients who showed better survival rates (79 vs. 41 months, P < 0.001). The first-line treatments of 2,970 patients were analyzed. The overall response rate was 71% including very good partial response or better in 31% of the 2,660 patients those were able to be evaluated. New drugs including bortezomib, thalidomide, and lenalidomide were used in 36% of 2,970 patients and affected OS when used as a first-line treatment.

Management of multiple myeloma in Asia: resource-stratified guidelines.

Treatment of multiple myeloma has undergone substantial developments in the past 10 years. The introduction of novel drugs has changed the treatment of the disease and substantially improved survival outcomes. Clinical practice guidelines based on evidence have been developed to provide recommendations on standard treatment approaches. However, the guidelines do not take into account resource limitations encountered by developing countries. The huge disparities in economy, health-care infrastructure, and access to novel drugs in Asian countries hinder the delivery of optimum care to every patient with multiple myeloma in Asia. In this Review we outline the guidelines that correspond with different levels of health-care resources and expertise, with the aim to unify diagnostic and therapeutic guidelines and help with the design of future studies in Asia.

Prognostic factors in 448 newly diagnosed multiple myeloma receiving bortezomib-based induction: impact of ASCT, transplant refusal and high-risk MM.

In Hong Kong, newly diagnosed multiple myeloma (NDMM) receives bortezomib-based triplet induction. Upfront autologous stem cell transplant (ASCT) is offered to transplant eligible (TE) patients (NDMM ≤ 65 years of age), unless medically unfit (TE-unfit) or refused (TE-refused). Data was retrieved for 448 patients to assess outcomes. For the entire cohort, multivariate analysis showed that male gender (p = 0.006), international staging system (ISS) 3 (p = 0.003), high lactate dehydrogenase (LDH) (p = 7.6 × 10-7) were adverse predictors for overall survival (OS), while complete response/ near complete response (CR/nCR) post-induction (p = 2.7 × 10-5) and ASCT (p = 4.8 × 10-4) were favorable factors for OS. In TE group, upfront ASCT was conducted in 252 (76.1%). Failure to undergo ASCT in TE patients rendered an inferior OS (TE-unfit p = 1.06 × 10-8, TE-refused p = 0.002) and event free survival (EFS) (TE-unfit p = 0.00013, TE-refused p = 0.002). Among TE patients with ASCT, multivariate analysis showed that age ≥ 60 (p = 8.9 × 10-4), ISS 3 (p = 0.019) and high LDH (p = 2.6 × 10-4) were adverse factors for OS. In those with high-risk features (HR cytogenetics, ISS 3, R-ISS 3), ASCT appeared to mitigate their adverse impact. Our data reaffirmed the importance of ASCT. The poor survival inherent with refusal of ASCT should be recognized by clinicians. Finally, improved outcome with ASCT in those with high-risk features warrant further studies.

Methylation profiling of SOCS1, SOCS2, SOCS3, CISH and SHP1 in Philadelphia-negative myeloproliferative neoplasm.

Janus kinase-signal transducer and activator of transcription (JAK/STAT) signalling, pivotal in Philadelphia-negative (Ph-ve) myeloproliferative neoplasm (MPN), is negatively regulated by molecules including SOCSs, CISH and SHP1. SOCS1, SOCS2 and SOCS3 methylation have been studied in MPN with discordant results. Herein, we studied the methylation status of SOCS1, SOCS2 and SOCS3, CISH and SHP1 by methylation-specific polymerase chain reaction (MSP) in cell lines and 45 diagnostic marrow samples of Ph-ve MPN. Moreover, we attempted to explain the discordance of methylation frequency by mapping the studied MSP primers to the respective genes. Methylation was detected in normal controls using SOCS2 MSP primers in the 3'translated exonic sequence, but not primers around the transcription start site in the 5' untranslated regions (5'UTR). SOCS1, SOCS2, SOCS3 and CISH were completely unmethylated in primary MPN samples and cell lines. In contrast, methylation of SHP1 was detected in 8.9% primary marrow samples. Moreover, SHP1 was completely methylated in K562 cell line, leading to reversible SHP1 silencing. A review of methylation studies of SOCS1 and SOCS3 showed that spuriously high rates of SOCS methylation had been reported using MSP primers targeting CpG sites in the 3'translated exonic sequence, which is also methylated in normal controls. However, using MSP primers localized to the 5'UTR, methylation of SOCS1, SOCS2 and SOCS3 is infrequent across all studies. In summary, methylation of SOCS1, SOCS2, SOCS3 and CISH is infrequent in Ph-ve MPN. Appropriate MSP primers are important for accurate estimation of the methylation frequency. The role of SHP1 methylation in the pathogenesis of MPN warrants further investigation.

Epigenetic inactivation of miR-9 family microRNAs in chronic lymphocytic leukemia--implications on constitutive activation of NFκB pathway.

BACKGROUND: The miR-9 family microRNAs have been identified as a tumor suppressor miRNA in cancers. We postulated that miR-9-1, miR-9-2 and miR-9-3 might be inactivated by DNA hypermethylation in chronic lymphocytic leukemia (CLL). METHODS: Methylation of miR-9-1, miR-9-2 and miR-9-3 was studied in eight normal controls including normal bone marrow, buffy coat, and CD19-sorted peripheral blood B-cells from healthy individuals, seven CLL cell lines, and seventy-eight diagnostic CLL samples by methylation-specific polymerase chain reaction. RESULTS: The promoters of miR-9-3 and miR-9-1 were both unmethylated in normal controls, but methylated in five (71.4%) and one of seven CLL cell lines respectively. However, miR-9-2 promoter was methylated in normal controls including CD19 + ve B-cells, hence suggestive of a tissue-specific but not tumor-specific methylation, and thus not further studied. Different MSP statuses of miR-9-3, including complete methylation, partial methylation, and complete unmethylation, were verified by quantitative bisulfite methylation analysis. 5-Aza-2'-deoxycytidine treatment resulted in miR-9-3 promoter demethylation and re-expression of pri-miR-9-3 in I83-E95 and WAC3CD5+ cells, which were homozygously methylated for miR-9-3. Moreover, overexpression of miR-9 led to suppressed cell proliferation and enhanced apoptosis together with downregulation of NFκB1 in I83-E95 cells, supporting a tumor suppressor role of miR-9-3 in CLL. In primary CLL samples, miR-9-3 was detected in 17% and miR-9-1 methylation in none of the patients at diagnosis. Moreover, miR-9-3 methylation was associated with advanced Rai stage (≥ stage 2) (P = 0.04). CONCLUSIONS: Of the miR-9 family, miR-9-3 is a tumor suppressor miRNA relatively frequently methylated, and hence silenced in CLL; whereas miR-9-1 methylation is rare in CLL. The role of miR-9-3 methylation in the constitutive activation of NFκB signaling pathway in CLL warrants further study.

Epigenetic inactivation of the MIR34B/C in multiple myeloma.

We postulated that MIR34B/C, a direct transcriptional target of TP53, might be inactivated by promoter hypermethylation in multiple myeloma (MM). MIR34B/C promoter methylation was studied in 8 normal marrow controls, 8 MM cell lines, 95 diagnostic, and 23 relapsed/progressed MM samples by methylation-specific PCR. MIR34B/C was methylated in 6 (75.0%) MM cell lines but not normal controls. 5-Aza-2'-deoxycytidine led to MIR34B/C promoter demethylation and MIR34B reexpression. Moreover, restoration of MIR34B led to reduced cellular proliferation and enhanced apoptosis of myeloma cells. In primary samples, methylation of MIR34B/C occurred in 5.3% at diagnosis and 52.2% at relapse/disease progression (P < .001). In 12 MM patients with paired samples at diagnosis and relapse/progression, MIR34B/C methylation was acquired in 6 at relapse/progression. In conclusion, MIR34B/C is a tumor suppressor in myeloma. Hypermethylation of MIR34B/C is tumor-specific. Frequent MIR34B/C hypermethylation during relapse/progression but not at diagnosis implicated a role of MIR34B/C hypermethylation in myeloma relapse/progression.

Establishment of a bortezomib-resistant Chinese human multiple myeloma cell line: MMLAL.

BACKGROUND: A new human myeloma cell line, MMLAL, was established from the myelomatous pleural effusion of a 73-year-old Chinese patient suffering from symptomatic International stage III IgG/lambda myeloma. After a brief period of complete remission, he developed aggressive systemic relapse complicated by malignant pleural effusion with exclusive plasma cell infiltration. His disease remained chemo-refractory, and died six months after relapse. METHODS: Purified mononuclear cells from the pleural effusion of the patient were cultured in the presence of IL-6. Continually growing cells were characterized by morphological, immunophenotypic, cytogenetic, fluorescence in situ hybridization (FISH) and TP53 mutation analyses. Cell proliferation was measured and compared with other myeloma cell lines by cell counting at day 3, 6, 9, and 12. Drug resistance against bortezomib, a proteasome inhibitor approved as a frontline chemotherapy for eligible myeloma patients, was evaluated and compared with other myeloma cell lines by MTT assay. RESULTS: Immunophenotypic analysis of the myeloma cells confirmed strong expression of plasma cell markers CD38 and CD138 but not T-cell or natural killer-cell marker CD56. Cytogenetic analysis of the myeloma cells showed a hypodiploid composite karyotype including loss of chromosome 13 and 17 or deletion of the short arm of chromosome 17, i.e. del(17p), in the form of isochromosome 17q10. FISH confirmed a hypodiploid karyotype with TP53 deletion but absence of t(4;14). Sequencing analysis of the TP53 gene indicated absence of mutation. Cell counting revealed that the maximum viable cell density was about 2.5 X 106 cells/ml. Upon bortezomib treatment, MTT assay reported an IC50 of 72.17nM, suggesting a strong bortezomib resistance. CONCLUSION: A hypodiploid with loss of chromosome 13 and loss or del(17p) human myeloma cell line, MMLAL, was established from the pleural effusion of a Chinese myeloma patient.