Heparanase (HPSE) gene polymorphism (rs12503843) contributes as a risk factor for hepatocellular carcinoma (HCC): a pilot study among Egyptian patients.

BACKGROUND: Heparanase activity was found to be included in human cancer development and growth. Heparanase (HPSE) gene single nucleotide polymorphisms (SNPs) have been found to be correlated with different human cancers. In the current study, we investigated whether HPSE SNPs were a hepatocellular carcinoma (HCC) risk factor by carrying out a comprehensive case-control pilot study. HPSE rs12331678 and rs12503843 were genotyped in 70 HCC-diagnosed patients and 30 healthy controls by modified amplification refractory mutation system (ARMS PCR) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. RESULTS: HPSE rs12331678 distributions showed that there were no statistically significant differences between both cohorts either in genotypic or allelic distribution but there was a significant correlation between the rs12503843 (T allele) and the HCC risk in the whole samples (P = 0.042). No significant association was observed between the HPSE rs12331678 and rs12503843 gene polymorphisms and all clinicopathologic markers or with SNP stratification based on HCV carrier in HCC groups. CONCLUSION: Our findings suggest for the first time the HPSE gene SNP characterization in HCC Egyptian patients, and our findings reveal there were associations between the HPSE rs12503843 (T allele) and the susceptibility to HCC.

Efficient role of IgH 3' regulatory region deficient B-cells in the development of oil granulomas.

Functional B-cells are essential for the formation of oil granulomas. The IgH 3' regulatory region (3'RR) activates important check-points during B-cell maturation. We investigated if 3'RR-deficient B-cells remain efficient to develop oil granulomas in response to pristine. B-cells expressing an IgH 3'RR-deficient allele were similarly recruited to wild type allele expressing B-cells in the granuloma. No differences were observed between 3'RR-deficient mice and control mice for granuloma numbers, cellular composition and ability to express mRNA transcripts for several pro- and anti-inflammatory cytokines. Altogether these results suggest a normal role for 3'RR-deficient B-cells in the development of an acute B-cell-mediated inflammatory response.

Elucidation of IgH 3' region regulatory role during class switch recombination via germline deletion.

In mature B cells, class switch recombination (CSR) replaces the expressed constant Cµ gene with a downstream C(H) gene. How the four transcriptional enhancers of the IgH 3' regulatory region (3'RR) control CSR remains an open question. We have investigated IgG1 CSR in 3'RR-deficient mice. Here we show that the 3'RR enhancers target the S(γ1) acceptor region (and poorly the S(µ) donor region) by acting on epigenetic marks, germline transcription, paused RNA Pol II recruitment, R loop formation, AID targeting and double-strand break generation. In contrast, location and diversity of S(µ)-S(γ1) junctions are not affected by deletion of the 3'RR enhancers. Thus, the 3'RR controls the first steps of CSR by priming the S acceptor region but is not implicated in the choice of the end-joining pathway.

The IgH 3' regulatory region influences lymphomagenesis in Igλ-Myc mice.

The IgH 3'regulatory region (3'RR), encompassing the four transcriptional enhancers hs3a-hs1,2-hs3b-hs4, has a key role on class switch recombination, somatic hypermutation, IgH transcription and B-cell fate. In plasma cells, transcribed IgH and IgL loci often colocalized in transcription factories and an IgL transcription defect might translate into lowered IgH transcription. We explored whether the 3'RR would affect lymphomagenesis in Igλ-Myc transgenic mice prone to lymphoproliferations. Breeding Igλ-Myc transgenics in a background deficient for the 3'RR influences lymphomagenesis toward less mature lymphomas (16% vs 54%, p = 0.01, Z test for two population proportions). In a 3'RR-deficient background mature tumors less often expressed the CD43 antigen (54% vs 0%, p = 0.02), a membrane glycoprotein expressed on activated mature B-cells. In contrast, in a 3'RR-deficient background tumors more often expressed the CD5 antigen (32% vs 12%, p = 0.05) that may serve to control autoimmunity and that is suspected to play a role in leukemic transformation. Lymphoma myc transcript levels, the Ki67 index of proliferation, the clonality, the usage of V(D)J segments, and their somatic hypermutation status were not affected in the 3'RR-deficient background. In conclusion, most probably through its action during the maturation process, the 3'RR can influence lymphomagenesis even when not linked with an oncogene.

The IgH 3' regulatory region governs µ chain transcription in mature B lymphocytes and the B cell fate.

We report that the IgH 3' regulatory region (3'RR) has no role on µ chain transcription and pre-BCR expression in B cell progenitors. In contrast, analysis of heterozygous IgH aΔ3'RR/bwt mice indicated that the 3'RR controls µ chain transcripts in mature splenocytes and impacts membrane IgM density without obvious effect on BCR signals (colocalisation with lipid rafts and phosphorylation of Erk and Akt after BCR crosslinking). Deletion of the 3'RR modulates the B cell fate to less marginal zone B cells. In conclusion, the 3'RR is dispensable for pre-BCR expression and necessary for optimal commitments toward the marginal zone B cell fate. These results reinforce the concept of a dual regulation of the IgH locus transcription and accessibility by 5' elements at immature B cell stages, and by the 3'RR as early as the resting mature B cell stage and then along further activation and differentiation.

Elucidation of the enigmatic IgD class-switch recombination via germline deletion of the IgH 3' regulatory region.

Classical class-switch recombination (cCSR) substitutes the Cµ gene with Cγ, Cε, or Cα, thereby generating IgG, IgE, or IgA classes, respectively. This activation-induced deaminase (AID)-driven process is controlled by the IgH 3' regulatory region (3'RR). Regulation of rare IgD CSR events has been enigmatic. We show that µÎ´CSR occurs in mouse mesenteric lymph node (MLN) B cells and is AID-dependent. AID attacks differ from those in cCSR because they are not accompanied by extensive somatic hypermutation (SHM) of targeted regions and because repaired junctions exhibit features of the alternative end-joining (A-EJ) pathway. In contrast to cCSR and SHM, µÎ´CSR is 3'RR-independent, as its absence affects neither breakpoint locations in Sµ- and Sδ-like (σ(δ)) nor mutation patterns at Sµ-σ(δ) junctions. Although mutations occur in the immediate proximity of the µÎ´ junctions, SHM is absent distal to the junctions within both Sµ and rearranged VDJ regions. In conclusion, µÎ´CSR is active in MLNs, occurs independently of 3'RR-driven assembly, and is even dramatically increased in 3'RR-deficient mice, further showing that its regulation differs from cCSR.

Targeting the oncogene B lymphoma deregulator IgH 3' regulatory region does not impede the in vivo inflammatory response in mice.

The IgH 3' regulatory region (3'RR), encompassing the four transcriptional enhancers hs3a-hs1,2-hs3b-hs4, is a potent lymphoma oncogene deregulator but its role in B cell-mediated inflammatory responses is unknown. We investigated the 3'RR involvement in the in vivo pristane-induced inflammatory response in BALB/c mice. The lack of the 3'RR in BALB/c mice had no wide effect on the incidence, the kinetic of development and the cellular composition of peritoneal ascites. Ascite pro-inflammatory cytokines levels (IL-6, IL-21, IL-12/23, TNF-α) were unchanged while anti-inflammatory cytokines levels (IL-10, interferon-γ) were slightly increased in 3'RR-deficient BALB/c mice as compared to wt BALB/c mice. In conclusion, the 3'RR is dispensable for the efficient recruitment of immune cells and the normal development of an inflammatory response in the in vivo pristane-induced inflammatory model. The 3'RR might be considered as a potential suitable target for anti-lymphoma pharmacological therapy without potent adverse effect on normal immune and inflammatory responses.