MKK4 activates non-canonical NFκB signaling by promoting NFκB2-p100 processing

Navigating the Cytokine Seas: Targeting Cytokine Signaling Pathways in Cancer Therapy

Cancer remains one of the leading causes of morbidity and mortality worldwide, necessitating continuous efforts to develop effective therapeutic strategies. Over the years, advancements in our understanding of the complex interplay between the immune system and cancer cells have led to the development of immunotherapies that revolutionize cancer treatment. Cytokines, as key regulators of the immune response, are involved in both the initiation and progression of cancer by affecting inflammation and manipulating multiple intracellular signaling pathways that regulate cell growth, proliferation, and migration. Cytokines, as key regulators of inflammation, have emerged as promising candidates for cancer therapy. This review article aims to provide an overview of the significance of cytokines in cancer development and therapy by highlighting the importance of targeting cytokine signaling pathways as a potential therapeutic approach.

MKK4 Inhibitors-Recent Development Status and Therapeutic Potential

MKK4 (mitogen-activated protein kinase kinase 4; also referred to as MEK4) is a dual-specificity protein kinase that phosphorylates and regulates both JNK (c-Jun N-terminal kinase) and p38 MAPK (p38 mitogen-activated protein kinase) signaling pathways and therefore has a great impact on cell proliferation, differentiation and apoptosis. Overexpression of MKK4 has been associated with aggressive cancer types, including metastatic prostate and ovarian cancer and triple-negative breast cancer. In addition, MKK4 has been identified as a key regulator in liver regeneration. Therefore, MKK4 is a promising target both for cancer therapeutics and for the treatment of liver-associated diseases, offering an alternative to liver transplantation. The recent reports on new inhibitors, as well as the formation of a startup company investigating an inhibitor in clinical trials, show the importance and interest of MKK4 in drug discovery. In this review, we highlight the significance of MKK4 in cancer development and other diseases, as well as its unique role in liver regeneration. Furthermore, we present the most recent progress in MKK4 drug discovery and future challenges in the development of MKK4-targeting drugs.

p52 signaling promotes cellular senescence

Background

Nuclear factor-κB is a multi-subunit transcription factor that plays a central role in cellular senescence. We previously reported that an increase in the p52 subunit is seen in senescent cells and aged tissue. In the current work, we examined the mechanism by which p52 is activated and whether the increase in p52 promotes senescence.

Results

Using both primary mouse embryonic fibroblasts (MEFs) and WI-38 human lung fibroblasts, we examined cells after serial passage and following prolonged culture. An increase in p52 was found in the nucleus relative to pre-senescent cells. The increase in p52 protein was not reflected by an increase in NFKB2 mRNA or by an increase in the abundance of upstream activating kinases, IKKα and NIK. To examine whether p52 promotes senescence, we over-expressed mature p52 in primary MEFs. Significantly more senescence was seen compared to control, a finding not seen with p52 mutated at critical DNA binding residues. In addition, blocking p52 nuclear translocation with the peptide inhibitor, SN52, decreased β-galactosidase (β-gal) formation. Subsequent filtration studies demonstrated that proteins in conditioned media (CM) were necessary for the increase in p52 and mass spectrometry identified S100A4 and cyclophilin A (CYPA) as potential factors in CM necessary for induction of p52. The requirement of these proteins in CM for induction of p52 was confirmed using depletion and supplementation studies. In addition, we found that activation of STAT3 signaling was required for the increase in p52. Finally, genome wide ChIP-sequencing analysis confirmed that there is an increase in p52 chromatin enrichment with senescence and identified several downstream factors whose expression is regulated by increased p52 binding.

Conclusions

These results demonstrate that p52 nuclear translocation is increased in senescent cells by factors in conditioned media and that mature p52 induces cellular senescence. The data are consistent with the prior observation that p52 is elevated in aged tissue and support the hypothesis that p52 contributes to organismal aging.

Supplementary information

The online version contains supplementary material available at 10.1186/s13578-022-00779-6.

miR520a-3p suppresses cell proliferation and metastasis by inhibiting the p65-NFκB pathway in glioblastoma

Background

miR520a-3p has previously had its antitumorigenic role in various types of cancers revealed, and been predicted as a posttranscriptional regulator of the NFκB-subunit RELA gene. Thus, miR520a-3p could function in carcinogenesis through suppressing RELA.

Methods

Expression of miR520a-3p and RELA mRNA was quantified in glioma and normal tissue, and the correlation between them was analyzed statistically. Also, receiver-operating characteristic (ROC)–curve analysis was performed. Effects of miR520a-3p on cell viability, colony formation, migration, and invasion wereexplored in vitro. Whether RELA was a direct target of miR520a-3p or not was analyzed. Finally, restoration of RELA on the effect of miR520a-3p overexpression on proliferation of glioblastoma cells was detected.

Results

Data showed that miR520a-3p expression was aberrantly downregulated and associated with malignance in glioma tissue. Areas under ROC curves of miR520a-3p and RELA mRNA expression were 0.9483 and 0.5967, respectively. Also, miR520a-3p expression was statistically correlated with RELA mRNA level in grade III–IV glioma tissue. Transfection of miR520a-3p mimic significantly increased miR520a-3p expression, and resulted in significant suppression of proliferation, migration, and invasion of glioblastoma cells in vitro. miR520a-3p overexpression resulted in statistical downregulation of RELA, both in mRNA and protein levels. RELA was direct target of miR520a-3p. In addition, restoration of RELA significantly weakened the inhibitory effect of miR520a-3p overexpression on viability and EdU-labeled glioblastoma cells.

Conclusion

These findings suggest that miR520a-3p should be helpful in auxiliary glioma diagnosis and can attenuate the proliferation and metastasis of glioblastoma through suppressing RELA, and thus could be an attractive therapeutic target to eliminate glioblastoma.

Evaluation of the association between the -1304T>G polymorphism in the promoter of the MKK4 gene and the risk of colorectal cancer: a PRISMA-compliant meta-analysis

Background

Colorectal cancer (CRC) is one of the most common cancers in China. Mitogen-activated protein kinase kinase 4 (MKK4) regulates tumorigenesis as a component of the MKK4 pathway. A number of studies have suggested a correlation between the MKK4 -1304T>G polymorphism and the risk of CRC. However, the results are still controversial. Therefore, we conducted a meta-analysis to obtain a more accurate assessment of the association between the MKK4 -1304T>G polymorphism and the risk of CRC.

Methods

Systematic literature searches were performed using PubMed, Embase, Cochrane Library, and CNKI. Four trials, including 1,255 cancer cases and 1,181 controls, were recruited in our study to assess the relationship of the MKK4 -1304T>G polymorphism with the risk of CRC.

Results

Four studies met our inclusion criteria and were finally included in the analysis, involving 1,255 cancer patients and 1,181 controls. Our meta-analysis revealed that the MKK4 -1304T>G polymorphism could reduce the risk of CRC (G vs. T: OR, 0.60, 95% CI: 0.48-0.76, P<0.0001; GG vs. TT: OR, 0.43, 95% CI: 0.29-0.62, P<0.0001; GG vs. TT + TG: OR, 0.50, 95% CI: 0.34-0.72, P=0.0003; TG + GG vs. TT: OR, 0.62, 95% CI: 0.53-0.73, P<0.0001; and TG vs. TT + GG: OR, 0.70, 95% CI: 0.59-0.82, P<0.0001).

Conclusions

In conclusion, our meta-analysis showed that the MKK4 -1304T>G polymorphism was associated with the susceptibility to CRC. In the future, large and well-designed case-control studies are needed to validate our findings.

Role of the NFκB-signaling pathway in cancer

Cancer is a group of cells that malignantly grow and proliferate uncontrollably. At present, treatment modes for cancer mainly comprise surgery, chemotherapy, radiotherapy, molecularly targeted therapy, gene therapy, and immunotherapy. However, the curative effects of these treatments have been limited thus far by specific characteristics of tumors. Abnormal activation of signaling pathways is involved in tumor pathogenesis and plays critical roles in growth, progression, and relapse of cancers. Targeted therapies against effectors in oncogenic signaling have improved the outcomes of cancer patients. NFκB is an important signaling pathway involved in pathogenesis and treatment of cancers. Excessive activation of the NFκB-signaling pathway has been documented in various tumor tissues, and studies on this signaling pathway for targeted cancer therapy have become a hot topic. In this review, we update current understanding of the NFκB-signaling pathway in cancer.