p38γ overexpression promotes osteosarcoma cell progression

Targeting the senescence-related genes MAPK12 and FOS to alleviate osteoarthritis

Background

The mechanism by which chondrocyte senescence aggravate OA progression has not yet been well elucidated. The aim of this study was to investigate the chondrocyte senescence related gene biosignatures in OA, and to analyze on the underlying mechanisms of senescence in OA.

Materials and methods

We intersected osteoarthritis dataset GSE82107 from GEO database and senescence dataset from CellAge database of human senescence-associated genes based on genetic manipulations experiments plus gene expression profilin, and screened out 4 overlapping genes. The hub genes were verified in vitro and in human OA cartilage tissues by qRT-PCR. We further confirmed the function of mitogen-activated protein kinase 12 (MAPK12) and Fos proto-oncogene (FOS) in OA in vitro and in vivo by qRT-PCR, western blotting, Edu staining, immunofluorescence, SA-β-gal staining, HE, IHC, von frey test, and hot plate.

Results

1458 downregulated and 218 upregulated DEGs were determined from GSE82107, and 279 human senescence-associated genes were downloaded from CellAge database. After intersection assay, we screened out 4 overlapping genes, of which FOS, CYR61 and TNFSF15 were upregulated, MAPK12 was downregulated. The expression of MAPK12 was obviously downregulated, whereas the expression profiles of FOS, CYR61 and TNFSF15 were remarkedly upregulated in H2O2- or IL-1β-stimulated C28/I2 cells, human OA cartilage tissues, and knee cartilage of aging mice. Furthermore, both MAPK12 over-expression and FOS knock-down can promote cell proliferation and cartilage anabolism, inhibit cell senescence and cartilage catabolism, relieve joint pain in H2O2- or IL-1β-stimulated C28/I2 cells and mouse primary chondrocytes, destabilization of the medial meniscus (DMM) mice.

Conclusion

This study explored that MAPK12 and FOS are involved in the occurrence and development of OA through modulating chondrocyte senescence. They might be biomarkers of OA chondrocyte senescence, and provides some evidence as subsequent possible therapeutic targets for OA.

The translational potential of this article

The translation potential of this article is that we revealed MAPK12 and FOS can effectively alleviate OA by regulating chondrocyte senescence, and thus provided potential therapeutic targets for prevention or treatment of OA in the future.

A retrospective analysis of the clinicopathological features and prognostic value of MAPK12 protein expression in diffuse large B-cell lymphoma

PURPOSE

Mitogen-activated protein kinase 12 (MAPK12), also known as p38γ, is a member of the p38 MAPK family and plays a crucial role in tumor occurrence and invasion. However, there is still uncertainty regarding MAPK12 involvement in diffuse large B-cell lymphoma (DLBCL).

METHODS

Our study investigated the expression of MAPK12 mRNA in various types of cancer using bioinformatic analysis. Furthermore, we performed immunohistochemistry (IHC) to detect the expression of MAPK12 in patients with DLBCL and compared clinical indicators and survival rates.

RESULTS

We found that the high expression rate of MAPK12 was 43.1% in DLBCL patients. Several clinical indicators, including IPI scores, Hans classifications, LDH levels, and Ki-67 expression were closely associated with MAPK12 expression. Survival analysis revealed that higher expression of MAPK12 was significantly correlated with shorter progression-free survival (PFS) and overall survival (OS) in DLBCL patients. In addition, both univariate and multivariate analyses revealed IPI score, MAPK12 expression, and rituximab use as the independent OS risk factors (P < 0.05). To explore the functional role of MAPK12 in DLBCL, weighted gene co-expression network analysis (WGCNA) and gene ontology (GO) were used to confirm the involvement of MAPK12 in the regulation of type II interferon production, positive regulation of lymphocyte proliferation, and other related biological processes.

CONCLUSION

DLBCL patients have poor prognoses when MAPK12 levels are high, which is expected to be a therapeutic target and prognostic factor.

Targeting the mitochondrial protein YME1L to inhibit osteosarcoma cell growth in vitro and in vivo

Exploring novel diagnostic and therapeutic biomarkers is extremely important for osteosarcoma. YME1 Like 1 ATPase (YME1L), locating in the mitochondrial inner membrane, is key in regulating mitochondrial plasticity and metabolic activity. Its expression and potential functions in osteosarcoma are studied in the present study. We show that YME1L mRNA and protein expression is significantly elevated in osteosarcoma tissues derived from different human patients. Moreover, its expression is upregulated in various primary and immortalized osteosarcoma cells. The Cancer Genome Atlas database results revealed that YME1L overexpression was correlated with poor overall survival and poor disease-specific survival in sarcoma patients. In primary and immortalized osteosarcoma cells, silencing of YME1L through lentiviral shRNA robustly inhibited cell viability, proliferation, and migration. Moreover, cell cycle arrest and apoptosis were detected in YME1L-silenced osteosarcoma cells. YME1L silencing impaired mitochondrial functions in osteosarcoma cells, causing mitochondrial depolarization, oxidative injury, lipid peroxidation and DNA damage as well as mitochondrial respiratory chain complex I activity inhibition and ATP depletion. Contrarily, forced YME1L overexpression exerted pro-cancerous activity and strengthened primary osteosarcoma cell proliferation and migration. YME1L is important for Akt-S6K activation in osteosarcoma cells. Phosphorylation of Akt and S6K was inhibited after YME1L silencing in primary osteosarcoma cells, but was strengthened with YME1L overexpression. Restoring Akt-mTOR activation by S473D constitutively active Akt1 mitigated YME1L shRNA-induced anti-osteosarcoma cell activity. Lastly, intratumoral injection of YME1L shRNA adeno-associated virus inhibited subcutaneous osteosarcoma xenograft growth in nude mice. YME1L depletion, mitochondrial dysfunction, oxidative injury, Akt-S6K inactivation, and apoptosis were detected in YME1L shRNA-treated osteosarcoma xenografts. Together, overexpressed YME1L promotes osteosarcoma cell growth, possibly by maintaining mitochondrial function and Akt-mTOR activation.

Identification of Potential p38γ Inhibitors via In Silico Screening, In Vitro Bioassay and Molecular Dynamics Simulation Studies

Protein kinase p38γ is an attractive target against cancer because it plays a pivotal role in cancer cell proliferation by phosphorylating the retinoblastoma tumour suppressor protein. Therefore, inhibition of p38γ with active small molecules represents an attractive alternative for developing anti-cancer drugs. In this work, we present a rigorous and systematic virtual screening framework to identify potential p38γ inhibitors against cancer. We combined the use of machine learning-based quantitative structure activity relationship modelling with conventional computer-aided drug discovery techniques, namely molecular docking and ligand-based methods, to identify potential p38γ inhibitors. The hit compounds were filtered using negative design techniques and then assessed for their binding stability with p38γ through molecular dynamics simulations. To this end, we identified a promising compound that inhibits p38γ activity at nanomolar concentrations and hepatocellular carcinoma cell growth in vitro in the low micromolar range. This hit compound could serve as a potential scaffold for further development of a potent p38γ inhibitor against cancer.

The pro-tumorigenic activity of p38γ overexpression in nasopharyngeal carcinoma

It is urgent to identify and validate biomarkers for early diagnosis and efficient treatment of nasopharyngeal carcinoma (NPC). Recent studies have proposed p38 gamma (p38γ) as a cyclin-dependent kinase (CDK)-like kinase that phosphorylates retinoblastoma (Rb) to promote cyclins expression and tumorigenesis. Here the Gene Expression Profiling Interactive Analysis (GEPIA) database and results from the local NPC tissues demonstrate that p38γ is significantly upregulated in NPC tissues, correlating with poor overall survival. Furthermore, p38γ mRNA and protein expression is elevated in established NPC cell lines (CNE-1 HONE-1 and CNE-2) and primary human NPC cells, but low expression detected in human nasal epithelial cells. In established and primary NPC cells, p38γ depletion, using the shRNA strategy or the CRISPR/Cas9 gene-editing method, largely inhibited cell growth, proliferation and migration, and induced significant apoptosis activation. Contrarily, ectopic p38γ overexpression exerted opposite activity and promoted NPC cell proliferation and migration. Retinoblastoma (Rb) phosphorylation and cyclin E1/A expression were decreased in NPC cells with p38γ silencing or knockout, but increased after p38γ overexpression. Moreover, mitochondrial subcellular p38γ localization was detected in NPC cells. Significantly, p38γ depletion disrupted mitochondrial functions, causing mitochondrial depolarization, reactive oxygen species production, oxidative injury and ATP depletion in NPC cells. In vivo, intratumoral injection of adeno-associated virus-packed p38γ shRNA potently inhibited primary human NPC xenograft growth in nude mice. In p38γ shRNA virus-injected NPC xenograft tissues, p38γ expression, Rb phosphorylation, cyclin E1/A expression and ATP levels were dramatically decreased. Taken together, we conclude that p38γ overexpression is required for NPC cell growth, acting as a promising therapeutic target of NPC.

Transcriptome Analysis Reveals the Anti-cancerous Mechanism of Licochalcone A on Human Hepatoma Cell HepG2

Hepatocellular carcinoma is a malignancy with a low survival rate globally, and there is imperative to unearth novel natural phytochemicals as effective therapeutic strategies. Licochalcone A is a chalcone from Glycyrrhiza that displayed various pharmacological efficacy. A globally transcriptome analysis was carried out to reveal the gene expression profiling to explore Licochalcone A's function as an anti-cancer phytochemical on HepG2 cells and investigate its potential mechanisms. Altogether, 6,061 dysregulated genes were detected (3,414 up-regulated and 2,647 down-regulated). SP1 was expected as the transcription factor that regulates the functions of most screened genes. GO and KEGG analysis was conducted, and the MAPK signaling pathway and the FoxO signaling pathway were two critical signal pathways. Protein-protein interaction (PPI) network analysis based on STRING platform to discover the hub genes (MAPK1, ATF4, BDNF, CASP3, etc.) in the MAPK signaling pathway and (AKT3, GADD45A, IL6, CDK2, CDKN1A, etc.) the FoxO signaling pathway. The protein level of essential genes that participated in significant pathways was consistent with the transcriptome data. This study will provide an inclusive understanding of the potential anti-cancer mechanism of Licochalcone A on hepatocellular, signifying Licochalcone A as a promising candidate for cancer therapy.

The Role of p38γ in Cancer: From review to outlook

p38γ is a member of the p38 Mitogen Activated Protein Kinases (p38 MAPKs). It contains four subtypes in mammalian cells encoded by different genes including p38α (MAPK14), p38β (MAPK11), p38γ (MAPK12), and p38δ (MAPK13). Recent studies revealed that p38γ may exhibit a crucial role in tumorigenesis and cancer aggressiveness. Despite the large number of published literatures, further researches are demanded to clarify its role in cancer development, the tissue-specific function and associated novel treatment strategies. In this article, we provide the latest view on the connection between p38γ and malignant tumors, highlighting the function of p38γ. The clinical value of p38γ is also discussed, helping the translation into the remarkable therapeutic strategy in tumor diseases.