Hit-and-run lymphomagenesis by the Bcl6 oncogene

miR-339-5p inhibits lung adenocarcinoma invasion and migration by directly targeting BCL6

Lung adenocarcinoma (LA) is a common non-small cell lung cancer, but effective biomarkers to diagnose early LA are still lacking. Increasing evidence has indicated that the dysregulation of microRNAs (miRNAs) play crucial roles in LA progression. miR-339-5p has been recently confirmed to exert crucial functions in various cancers. Nevertheless, molecular mechanisms and effects of miR-339-5p on LA development still remain vague. In the present research, miR-339-5p expression was downregulated in human LA tissues. miR-339-5p overexpression in LA cells could remarkably suppress the LA cell invasion and migration. In addition, further studies indicated that miR-339-5p overexpression downregulated both the B-cell lymphoma 6 (BCL6) mRNA and protein expressions by targeting the BCL6 3′-UTR directly. Moreover, BCL6 knockdown could partially lessen the function of miR-339-5p in LA invasion and migration. In conclusion, the present data identified miR-339-5p as a novel LA suppressor which exerted its functions partly by negatively regulating BCL6.

NLRP3 inflammasome activation plays a carcinogenic role through effector cytokine IL-18 in lymphoma

Inflammasomes play important roles in the pathogenesis of tumors, but the roles of NLRP3 inflammasome in the lymphoma remain unclear. Activated NLRP3 inflammasome induces the maturation of its effector cytokine IL-18 which functions in the development of cancer. Here, we investigated the polymorphism and expression of NLRP3 inflammasome related genes and explored their function in lymphoma. We found that IL-18 (rs1946518) and NFκB94 ins/del (rs28362491) contributed to lymphoma susceptibility and allele G in IL-18 was significantly associated with the risk of lymphoma. The mRNA and plasma expression levels of IL-18 were significantly elevated in primary lymphoma patients and decreased after remission. NLRP3 inflammasome could be activated by ATP plus LPS in lymphoma cells accompanied with the increasing expression of NLRP3-related genes. NLRP3 inflammasome activation reduced the dexamethasone-induced proliferation-inhibiting effect by promoting cells into S phase. NLRP3 inflammasome activation promoted lymphoma cells proliferation and inhibited apoptosis through up-regulation of c-myc and bcl-2, and down-regulation of TP53 and bax, and then reduced the anti-tumor effect of dexamethasone. Similar with the activation of NLRP3, the effector cytokine IL-18 also had the proliferation-promoting, apoptosis-inhibiting and resistance-reducing effects on lymphoma cells via shifting the balance of c-myc/TP53 and bcl-2/bax. Moreover, neutralizing IL-18 has the opposite effects. In conclusion, NLRP3 inflammasome contributes to the susceptibility and plays a carcinogenic role through its effector cytokine IL-18 in lymphoma.

KRAS as a Therapeutic Target

KRAS proteins play a major role in human cancer, but have not yielded to therapeutic attack. New technologies in drug discovery and insights into signaling pathways that KRAS controls have promoted renewed efforts to develop therapies through direct targeting of KRAS itself, new ways of blocking KRAS processing, or by identifying targets that KRAS cancers depend on for survival. Although drugs that block the well-established downstream pathways, RAF-MAPK and PI3K, are being tested in the clinic, new efforts are under way to exploit previously unrecognized vulnerabilities, such as altered metabolic networks, or novel pathways identified through synthetic lethal screens. Furthermore, new ways of suppressing KRAS gene expression and of harnessing the immune system offer further hope that new ways of treating KRAS are finally coming into view. These issues are discussed in this edition of CCR Focus.

Inherited Inflammatory Response Genes Are Associated with B-Cell Non-Hodgkin's Lymphoma Risk and Survival

BACKGROUND

Malignant B-cell clones are affected by both acquired genetic alterations and by inherited genetic variations changing the inflammatory tumour microenvironment.

METHODS

We investigated 50 inflammatory response gene polymorphisms in 355 B-cell non-Hodgkin's lymphoma (B-NHL) samples encompassing 216 diffuse large B cell lymphoma (DLBCL) and 139 follicular lymphoma (FL) and 307 controls. The effect of single genes and haplotypes were investigated and gene-expression analysis was applied for selected genes. Since interaction between risk genes can have a large impact on phenotype, two-way gene-gene interaction analysis was included.

RESULTS

We found inherited SNPs in genes critical for inflammatory pathways; TLR9, IL4, TAP2, IL2RA, FCGR2A, TNFA, IL10RB, GALNT12, IL12A and IL1B were significantly associated with disease risk and SELE, IL1RN, TNFA, TAP2, MBL2, IL5, CX3CR1, CHI3L1 and IL12A were, associated with overall survival (OS) in specific diagnostic entities of B-NHL. We discovered noteworthy interactions between DLBCL risk alleles on IL10 and IL4RA and FL risk alleles on IL4RA and IL4. In relation to OS, a highly significant interaction was observed in DLBCL for IL4RA (rs1805010) * IL10 (rs1800890) (HR = 0.11 (0.02-0.50)). Finally, we explored the expression of risk genes from the gene-gene interaction analysis in normal B-cell subtypes showing a different expression of IL4RA, IL10, IL10RB genes supporting a pathogenetic effect of these interactions in the germinal center.

CONCLUSIONS

The present findings support the importance of inflammatory genes in B-cell lymphomas. We found association between polymorphic sites in inflammatory response genes and risk as well as outcome in B-NHL and suggest an effect of gene-gene interactions during the stepwise oncogenesis.

Inherited variation in immune response genes in follicular lymphoma and diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL) both depend on immune-mediated survival and proliferation signals from the tumor microenvironment. Inherited genetic variation influences this complex interaction. A total of 89 studies investigating immune-response genes in DLBCL and FL were critically reviewed. Relatively consistent association exists for variation in the tumor necrosis factor alpha (TNFA) and interleukin-10 loci and DLBCL risk; for DLBCL outcome association with the TNFA locus exists. Variations at chromosome 6p31-32 were associated with FL risk. Importantly, individual risk alleles have been shown to interact with each other. We suggest that the pathogenetic impact of polymorphic genes should include gene-gene interaction analysis and should be validated in preclinical model systems of normal B lymphopoiesis and B-cell malignancies. In the future, large cohort studies of interactions and genome-wide association studies are needed to extend the present findings and explore new risk alleles to be studied in preclinical models.