In chronic lymphocytic leukemia (CLL), the role of complex karyotype (CK) for prognostic stratification remains a topic of debate, and the impact of specific cytogenetic abnormalities is still unclear. This study aims to investigate the clinical and biological features of CLL with t(14;19)(q32;q13) (tCLL) involving the BCL3 gene. Patients with tCLL were younger and more commonly presented unmutated IGHV gene, subset #8 stereotypy, trisomy of chromosome 12, and complex karyotype than other patients without t(14;19) (oCLL). The presence of t(14;19) was associated with a shorter time to treatment and overall survival compared to oCLL. Gene expression analysis revealed a unique transcriptome profile in tCLL, characterized by the upregulation of BCL3 and the activation of B-cell receptor, PI3K-Akt. Conversely, apoptosis-related pathways were suppressed in tCLL. While the BTK gene was upregulated, the BCL2L11 gene, coding for the pro-apoptotic protein BIM, was downregulated. Notably, patients with tCLL were characterized by a trend (p = 0.058) for a longer time to the next treatment with BTK inhibitors (BTKi) compared to those treated with a venetoclax-based (Ven-based) regimen. We underscore the adverse outcomes of tCLL, its distinct molecular features and gene expression patterns. Therefore, our data suggest that identifying tCLL could help tailor therapeutic approaches.

• Publikační typ
• časopisecké články MeSH

The TP63 gene encodes two major protein variants; TAp63 contains a p53-like transcription domain and consequently has tumor suppressor activities whereas ΔNp63 lacks this domain and acts as an oncogene. The two variants show distinct expression patterns in normal tissues and tumors, with lymphocytes and lymphomas/leukemias expressing TAp63, and basal epithelial cells and some carcinomas expressing high levels of ΔNp63, most notably squamous cell carcinomas (SCC). Whilst the transcriptional functions of TAp63 and ΔNp63 isoforms are known, the mechanisms involved in their regulation are poorly understood. Using squamous epithelial cells that contain high levels of ΔNp63 and low/undetectable TAp63, the DNA demethylating agent decitabine (5-aza-2'-deoxycytidine, 5-dAza) caused a dose-dependent increase in TAp63, with a simultaneous reduction in ΔNp63, indicating DNA methylation-dependent regulation at the isoform-specific promoters. The basal cytokeratin KRT5, a direct ΔNp63 transcriptional target, was also reduced, confirming functional alteration of p63 activity after DNA demethylation. We also showed high level methylation of three CpG sites in the TAP63 promoter in these cells, which was reduced by decitabine. DNMT1 depletion using inducible shRNAs partially replicated these effects, including an increase in the ratio of TAP63:ΔNP63 mRNAs, a reduction in ΔNp63 protein and reduced KRT5 mRNA levels. Finally, high DNA methylation levels were found at the TAP63 promoter in clinical SCC samples and matched normal tissues. We conclude that DNA methylation at the TAP63 promoter normally silences transcription in squamous epithelial cells, indicating DNA methylation as a therapeutic approach to induce this tumor suppressor in cancer. That decitabine simultaneously reduced the oncogenic activity of ΔNp63 provides a "double whammy" for SCC and other p63-positive carcinomas. Whilst a variety of mechanisms may be involved in producing the opposite effects of DNA demethylation on TAp63 and ΔNp63, we propose an "either or" mechanism in which TAP63 transcription physically interferes with the ability to initiate transcription from the downstream ΔNP63 promoter on the same DNA strand. This mechanism can explain the observed inverse expression of p63 isoforms in normal cells and cancer.

• Klíčová slova
• DNA methylation, TAp63, alternative promoter usage, decitabine, keratinocytes, squamous cell carcinoma, ΔNp63,
• Publikační typ
• časopisecké články MeSH

Chronic lymphocytic leukemia (CLL) is characterized by the existence of subsets of patients with (quasi)identical, stereotyped B-cell receptor (BcR) immunoglobulins. Patients in certain major stereotyped subsets often display remarkably consistent clinicobiological profiles, suggesting that the study of BcR immunoglobulin stereotypy in CLL has important implications for understanding disease pathophysiology and refining clinical decision-making. Nevertheless, several issues remain open, especially pertaining to the actual frequency of BcR immunoglobulin stereotypy and major subsets, as well as the existence of higher-order connections between individual subsets. To address these issues, we investigated clonotypic IGHV-IGHD-IGHJ gene rearrangements in a series of 29 856 patients with CLL, by far the largest series worldwide. We report that the stereotyped fraction of CLL peaks at 41% of the entire cohort and that all 19 previously identified major subsets retained their relative size and ranking, while 10 new ones emerged; overall, major stereotyped subsets had a cumulative frequency of 13.5%. Higher-level relationships were evident between subsets, particularly for major stereotyped subsets with unmutated IGHV genes (U-CLL), for which close relations with other subsets, termed "satellites," were identified. Satellite subsets accounted for 3% of the entire cohort. These results confirm our previous notion that major subsets can be robustly identified and are consistent in relative size, hence representing distinct disease variants amenable to compartmentalized research with the potential of overcoming the pronounced heterogeneity of CLL. Furthermore, the existence of satellite subsets reveals a novel aspect of repertoire restriction with implications for refined molecular classification of CLL.

• MeSH
• chronická lymfatická leukemie genetika   MeSH
• frekvence genu MeSH
• genová přestavba MeSH
• lidé MeSH
• somatická hypermutace imunoglobulinových genů MeSH
• těžké řetězce imunoglobulinů genetika   MeSH
• variabilní oblast imunoglobulinu genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• těžké řetězce imunoglobulinů MeSH
• variabilní oblast imunoglobulinu MeSH

BACKGROUND: In order to gain insight into the contribution of DNA methylation to disease progression of chronic lymphocytic leukemia (CLL), using 450K Illumina arrays, we determined the DNA methylation profiles in paired pre-treatment/relapse samples from 34 CLL patients treated with chemoimmunotherapy, mostly (n = 31) with the fludarabine-cyclophosphamide-rituximab (FCR) regimen. RESULTS: The extent of identified changes in CLL cells versus memory B cells from healthy donors was termed "epigenetic burden" (EB) whereas the number of changes between the pre-treatment versus the relapse sample was termed "relapse changes" (RC). Significant (p < 0.05) associations were identified between (i) high EB and short time-to-first-treatment (TTFT); and, (ii) few RCs and short time-to-relapse. Both the EB and the RC clustered in specific genomic regions and chromatin states, including regulatory regions containing binding sites of transcription factors implicated in B cell and CLL biology. CONCLUSIONS: Overall, we show that DNA methylation in CLL follows different dynamics in response to chemoimmunotherapy. These epigenetic alterations were linked with specific clinical and biological features.

• Klíčová slova
• CLL, Chemoimmunotherapy, DNA methylation, Microarray analysis, Relapse,
• MeSH
• chronická lymfatická leukemie farmakoterapie   genetika   MeSH
• cyklofosfamid farmakologie   terapeutické užití   MeSH
• dospělí MeSH
• epigeneze genetická účinky léků   MeSH
• genové regulační sítě účinky léků   MeSH
• imunoterapie MeSH
• lidé středního věku MeSH
• lidé MeSH
• longitudinální studie MeSH
• metylace DNA účinky léků   MeSH
• progrese nemoci MeSH
• rituximab farmakologie   terapeutické užití   MeSH
• sekvenční analýza hybridizací s uspořádaným souborem oligonukleotidů MeSH
• senioři MeSH
• vidarabin analogy a deriváty   farmakologie   terapeutické užití   MeSH
• výsledek terapie MeSH
• vysoce účinné nukleotidové sekvenování metody   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• cyklofosfamid MeSH
• fludarabine MeSH Prohlížeč
• rituximab MeSH
• vidarabin MeSH