p38γ overexpression in gliomas and its role in proliferation and apoptosis

Identification of Key Immune and Cell Cycle Modules and Prognostic Genes for Glioma Patients through Transcriptome Analysis

BACKGROUND

Gliomas, the most prevalent type of primary brain tumor, stand out as one of the most aggressive and lethal types of human cancer.

METHODS & RESULTS

To uncover potential prognostic markers, we employed the weighted correlation network analysis (WGCNA) on the Chinese Glioma Genome Atlas (CGGA) 693 dataset to reveal four modules significantly associated with glioma clinical traits, primarily involved in immune function, cell cycle regulation, and ribosome biogenesis. Using the least absolute shrinkage and selection operator (LASSO) regression algorithm, we identified 11 key genes and developed a prognostic risk score model, which exhibits precise prognostic prediction in the CGGA 325 dataset. More importantly, we also validated the model in 12 glioma patients with overall survival (OS) ranging from 4 to 132 months using mRNA sequencing and immunohistochemical analysis. The analysis of immune infiltration revealed that patients with high-risk scores exhibit a heightened immune infiltration, particularly immune suppression cells, along with increased expression of immune checkpoints. Furthermore, we explored potentially effective drugs targeting 11 key genes for gliomas using the library of integrated network-based cellular signatures (LINCS) L1000 database, identifying that in vitro, both torin-1 and clofarabine exhibit promising anti-glioma activity and inhibitory effect on the cell cycle, a significant pathway enriched in the identified glioma modules.

CONCLUSIONS

In conclusion, our study provides valuable insights into molecular mechanisms and identifying potential therapeutic targets for gliomas.

The levels of immunosuppressive checkpoint protein PD-L1 and tumor-infiltrating lymphocytes were integrated to reveal the glioma tumor microenvironment

In spite of significant strides in the realm of cancer biology and therapeutic interventions, the clinical prognosis for patients afflicted with glioblastoma (GBM) remains distressingly dismal. The tumor immune microenvironment (TIME), a crucial player in the progression, treatment response, and prognostic trajectory of glioma, warrants thorough exploration. Within this intricate microcosm, the immunosuppressive checkpoint protein PD-L1 and tumor-infiltrating lymphocytes (TILs) emerge as pivotal constituents, underscoring their potential role in deciphering glioma biology and informing treatment strategies. However, prognostic models based on the association between PD-L1 expression and TIL infiltration in the tumor immune microenvironment have not been established. The aim of this study was to explore TIME genes associated with PD-L1 expression and TIL invasion and to construct a risk score for predicting the overall survival (OS) of GBM patients based on these genes. The samples were separately classified according to the PD-L1 expression level and TIL score and TIME-related genes were identified using differential expression and weighted gene co-expression network analysis. The DEGs were subjected to least absolute contraction and selection operator (LASSO) -Cox regression to construct TIME associated risk score (TIMErisk). A TIMErisk was developed based on STEAP3 and CXCL13 genes. The STLEAP3 was demonstrated to be involved in glioma progression. The results showed that the patients in the high TIMErisk group had poor OS compared with subjects in the low TIMErisk group. The biological phenotypes associated with TIMErisk were analyzed in terms of functional enrichment, tumor immune profile, and tumor mutation profile. The results on tumor immune dysfunction and exclusion dysfunction (TIDE) score and immune surface score (IPS) showed that GBM patients with different TIME risks had different responses to immunotherapy. Tumor purity analysis indicated that PD-L1 and TIL scores were positively correlated with TIMErisk score and negatively correlated with tumor purity. These results show that the TIMErisk-based prognostic model had high predictive value for the prognosis and immune characteristics of GBM patients. Immunohistochemical staining images of patients in the high and low TIMErisk groups were analyzed, showing that the degree of immune cell infiltration was higher in the high TIMErisk group relative to the low TIMErisk group. The present study provides a basis for understanding glioma tumor microenvironment and a foundation for conducting comprehensive immunogenomic analysis.

P38 kinase in gastrointestinal cancers

Gastrointestinal cancers are a leading cause of cancer morbidity and mortality worldwide with 4.2 million new cases and 3.2 million deaths estimated in 2020. Despite the advances in primary and adjuvant therapies, patients still develop distant metastases and require novel therapies. Mitogen‑activated protein kinase (MAPK) cascades are crucial signaling pathways that regulate many cellular processes, including proliferation, differentiation, apoptosis, stress responses and cancer development. p38 Mitogen Activated Protein Kinases (p38 MAPKs) includes four isoforms: p38α (MAPK14), p38β (MAPK11), p38γ (MAPK12), and p38δ (MAPK13). p38 MAPK was first identified as a stress response protein kinase that phosphorylates different transcriptional factors. Dysregulation of p38 pathways, in particular p38γ, are associated with cancer development, metastasis, autophagy and tumor microenvironment. In this article, we provide an overview of p38 and p38γ with respect to gastrointestinal cancers. Furthermore, targeting p38γ is also discussed as a potential therapy for gastrointestinal cancers.

Anticancer Mechanism of Flavonoids on High-Grade Adult-Type Diffuse Gliomas

High-grade adult-type diffuse gliomas are the most common and deadliest malignant adult tumors of the central nervous system. Despite the advancements in the multimodality treatment of high-grade adult-type diffuse gliomas, the five-year survival rates still remain poor. The biggest challenge in treating high-grade adult-type diffuse gliomas is the intra-tumor heterogeneity feature of the glioma tumors. Introducing dietary flavonoids to the current high-grade adult-type diffuse glioma treatment strategies is crucial to overcome this challenge, as flavonoids can target several molecular targets. This review discusses the anticancer mechanism of flavonoids (quercetin, rutin, chrysin, apigenin, naringenin, silibinin, EGCG, genistein, biochanin A and C3G) through targeting molecules associated with high-grade adult-type diffuse glioma cell proliferation, apoptosis, oxidative stress, cell cycle arrest, migration, invasion, autophagy and DNA repair. In addition, the common molecules targeted by the flavonoids such as Bax, Bcl-2, MMP-2, MMP-9, caspase-8, caspase-3, p53, p38, Erk, JNK, p38, beclin-1 and LC3B were also discussed. Moreover, the clinical relevance of flavonoid molecular targets in high-grade adult-type diffuse gliomas is discussed with comparison to small molecules inhibitors: ralimetinib, AMG232, marimastat, hydroxychloroquine and chloroquine. Despite the positive pre-clinical results, further investigations in clinical studies are warranted to substantiate the efficacy and safety of the use of flavonoids on high-grade adult-type diffuse glioma patients.

The functional role of p38 MAPK pathway in malignant brain tumors

Gliomas are extremely debilitating malignant brain tumors with very limited response to therapies. The initiation and progression of gliomas can be attributed to several molecular abnormalities, such as mutations in important regulatory networks. In this regard, the mitogen-activated protein kinases (MAPKs) arise as key signaling pathways involved in cell proliferation, survival, and differentiation. MAPK pathway has been altered in most glial tumors. In glioma cells, the activation of p38 MAPK contributes to tumor invasion and metastasis and is positively correlated with tumor grade, being considered a potential oncogenic factor contributing to brain tumorigenesis and chemotherapy resistance. Hence, a better understanding of glioma pathogenesis is essential to the advancement of therapies that provide extended life expectancy for glioma patients. This review aims to explore the role of the p38 MAPK pathway in the genesis and progression of malignant brain tumors.

Mechanisms of Cell Cycle Arrest and Apoptosis in Glioblastoma

Cells of glioblastoma, the most frequent primary malignant brain tumor, are characterized by their rapid growth and infiltration of adjacent healthy brain parenchyma, which reflects their aggressive biological behavior. In order to maintain their excessive proliferation and invasion, glioblastomas exploit the innate biological capacities of the patients suffering from this tumor. The pathways involved in cell cycle regulation and apoptosis are the mechanisms most commonly affected. The following work reviews the regulatory pathways of cell growth in general as well as the dysregulated cell cycle and apoptosis relevant mechanisms observed in glioblastomas. We then describe the molecular targeting of the current established adjuvant therapy and present ongoing trials or completed studies on specific promising therapeutic agents that induce cell cycle arrest and apoptosis of glioblastoma cells.

The p38 MAPK Components and Modulators as Biomarkers and Molecular Targets in Cancer

The mitogen-activated protein kinase (MAPK) family is an important bridge in the transduction of extracellular and intracellular signals in different responses at the cellular level. Within this MAPK family, the p38 kinases can be found altered in various diseases, including cancer, where these kinases play a fundamental role, sometimes with antagonistic mechanisms of action, depending on several factors. In fact, this family has an immense number of functionalities, many of them yet to be discovered in terms of regulation and action in different types of cancer, being directly involved in the response to cancer therapies. To date, three main groups of MAPKs have been identified in mammals: the extracellular signal-regulated kinases (ERK), Jun N-terminal kinase (JNK), and the different isoforms of p38 (α, β, γ, δ). In this review, we highlight the mechanism of action of these kinases, taking into account their extensive regulation at the cellular level through various modifications and modulations, including a wide variety of microRNAs. We also analyze the importance of the different isoforms expressed in the different tissues and their possible role as biomarkers and molecular targets. In addition, we include the latest preclinical and clinical trials with different p38-related drugs that are ongoing with hopeful expectations in the present/future of developing precision medicine in cancer.

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.

A comprehensive prognostic signature for glioblastoma patients based on transcriptomics and single cell sequencing

PURPOSE

Glioblastoma (GBM) is the most common and deadly brain tumor. We aimed to reveal potential prognostic GBM marker genes, elaborate their functions, and build an effective a prognostic model for GBM patients.

METHODS

Through data mining of The Cancer Genome Atlas (TCGA) and the Chinese Glioma Genome Atlas (CGGA), we screened for significantly differentially expressed genes (DEGs) to calculate risk scores for individual patients. Published data of somatic mutation and copy number variation profiles were analyzed for distinct genomic alterations associated with risk scores. In addition, single-cell sequencing was used to explore the biological functions of the identified prognostic marker genes. By combining risk scores and other clinical features, we built a comprehensive prognostic GBM model.

RESULTS

Seven DEGs (CLEC5A, HOXC6, HOXA5, CCL2, GPRASP1, BSCL2 and PTX3) were identified as being prognostic for GBM. Expression of these genes was confirmed in different GBM cell lines using real-time PCR. Risk scores calculated from the seven DEGs revealed prognostic value irrespective of other clinical factors, including IDH mutation status, and were negatively correlated with TP53 expression. The prognostic genes were found to be associated with tumor proliferation and progression based on pseudo-time analysis in neoplastic cells. A final prognostic model was developed and validated with a good performance, especially in geriatric GBM patients.

CONCLUSIONS

Using genetic profiles, age, IDH mutation status, and chemotherapy and radiotherapy, we constructed a comprehensive prognostic model for GBM patients. The model has a good performance, especially in geriatric GBM patients.

Anticancer Mechanism of Curcumin on Human Glioblastoma

Glioblastoma (GBM) is the most malignant brain tumor and accounts for most adult brain tumors. Current available treatment options for GBM are multimodal, which include surgical resection, radiation, and chemotherapy. Despite the significant advances in diagnostic and therapeutic approaches, GBM remains largely resistant to treatment, with a poor median survival rate between 12 and 18 months. With increasing drug resistance, the introduction of phytochemicals into current GBM treatment has become a potential strategy to combat GBM. Phytochemicals possess multifarious bioactivities with multitarget sites and comparatively marginal toxicity. Among them, curcumin is the most studied compound described as a potential anticancer agent due to its multi-targeted signaling/molecular pathways properties. Curcumin possesses the ability to modulate the core pathways involved in GBM cell proliferation, apoptosis, cell cycle arrest, autophagy, paraptosis, oxidative stress, and tumor cell motility. This review discusses curcumin’s anticancer mechanism through modulation of Rb, p53, MAPK, P13K/Akt, JAK/STAT, Shh, and NF-κB pathways, which are commonly involved and dysregulated in preclinical and clinical GBM models. In addition, limitation issues such as bioavailability, pharmacokinetics perspectives strategies, and clinical trials were discussed.

p38γ overexpression promotes osteosarcoma cell progression

Osteosarcoma (OS) is the most common primary bone malignancy in the adolescent population. Recent studies demonstrate that p38 gamma (p38γ) phosphorylates retinoblastoma (Rb) to promote cyclin expression, cell-cycle entry and tumorigenesis. Studying the potential function of p38γ in human OS, we show that p38γ mRNA and protein expression are significantly elevated in OS tissues and OS cells, whereas its expression is relatively low in normal bone tissue and in human osteoblasts/osteoblastic cells. Knockdown of p38γ in established (U2OS) and primary human OS cells potently inhibited cell growth, proliferation, migration and invasion, while promoting cell apoptosis. Furthermore, CRISPR/Cas9-induced p38γ knockout inhibited human OS cell progression in vitro. Conversely, ectopic overexpression of p38γ in primary human OS cells augmented cell growth, proliferation and migration. Signaling studies show that retinoblastoma (Rb) phosphorylation and cyclin E1/cyclin A expression were decreased following p38γ shRNA knockdown and knockout, but increased after ectopic p38γ overexpression. Collectively, these results show that p38γ overexpression promotes human OS cell progression.

Functions of p38 MAP Kinases in the Central Nervous System

Mitogen-activated protein (MAP) kinases are a central component in signaling networks in a multitude of mammalian cell types. This review covers recent advances on specific functions of p38 MAP kinases in cells of the central nervous system. Unique and specific functions of the four mammalian p38 kinases are found in all major cell types in the brain. Mechanisms of p38 activation and downstream phosphorylation substrates in these different contexts are outlined and how they contribute to functions of p38 in physiological and under disease conditions. Results in different model organisms demonstrated that p38 kinases are involved in cognitive functions, including functions related to anxiety, addiction behavior, neurotoxicity, neurodegeneration, and decision making. Finally, the role of p38 kinases in psychiatric and neurological conditions and the current progress on therapeutic inhibitors targeting p38 kinases are covered and implicate p38 kinases in a multitude of CNS-related physiological and disease states.

α-Hispanolol Induces Apoptosis and Suppresses Migration and Invasion of Glioblastoma Cells Likely via Downregulation of MMP-2/9 Expression and p38MAPK Attenuation

α-Hispanolol (α-H) is a labdane diterpenoid that has been shown to induce apoptosis in several human cancer cells. However, the effect of α-H in human glioblastoma cells has not been described. In the present work, we have investigated the effects of α-H on apoptosis, migration, and invasion of human glioblastoma cells with the aim of identifying the molecular targets underlying its mechanism of action. The results revealed that α-H showed significant cytotoxicity against human glioma cancer cell lines U87 and U373 in a concentration- and time-dependent manner. This effect was higher in U87 cells and linked to apoptosis, as revealed the increased percentage of sub-G₁ population by cell cycle analysis and acquisition of typical features of apoptotic cell morphology. Apoptosis was also confirmed by significant presence of annexin V-positive cells and caspase activation. Pretreatment with caspase inhibitors diminishes the activities of caspase 8, 9, and 3 and maintains the percentage of viable glioblastoma cells, indicating that α-H induced cell apoptosis through both the extrinsic and the intrinsic pathways. Moreover, we also found that α-H downregulated the anti-apoptotic Bcl-2 and Bcl-xL proteins and activated the pro-apoptotic Bid and Bax proteins. On the other hand, α-H exhibited inhibitory effects on the migration and invasion of U87 cells in a concentration-dependent manner. Furthermore, additional experiments showed that α-H treatment reduced the enzymatic activities and protein levels of matrix metalloproteinase MMP-2 and MMP-9 and increased the expression of TIMP-1 inhibitor, probably via p38MAPK regulation. Finally, xenograft assays confirmed the anti-glioma efficacy of α-H. Taken together, these findings suggest that α-H may exert anti-tumoral effects in vitro and in vivo through the inhibition of cell proliferation and invasion as well as by the induction of apoptosis in human glioblastoma cells. This research describes α-H as a new drug that may improve the therapeutic efficacy against glioblastoma tumors.

Targeting p38γ to inhibit human colorectal cancer cell progression

Colorectal cancer (CRC) is a common malignancy globally causing significant cancer-related mortality. Recent studies have proposed p38gamma (p38γ) as a novel cyclin-dependent kinase (CDK)-like kinase, promoting tumorigenesis and cancer progression. The current study evaluates p38γ expression and potential role in CRC. In HT-29 cells and primary human colon cancer cells, shRNA-induced p38γ silencing or CRISPR/Cas9-mediated p38γ knockout inhibited cell growth, proliferation, and migration, and induced significant apoptosis. Conversely, ectopic overexpression of p38γ further promoted the growth, proliferation, and migration of HT-29 cells and primary colon cancer cells. Retinoblastoma (Rb) phosphorylation and cyclins (E1/A) expression were decreased by p38γ silencing or KO, but increased with p38γ overexpression. p38γ mRNA and protein levels are significantly upregulated in human colon cancer tissues, when compared to levels in surrounding colon epithelial tissues. These results demonstrate that overexpression of p38γ can promote human CRC cell progression, and identify p38γ as a novel therapeutic target.

Melatonin Modulates the Microenvironment of Glioblastoma Multiforme by Targeting Sirtuin 1

Natural products have historically been regarded as an important resource of therapeutic agents. Resveratrol and melatonin have been shown to increase SIRT1 activity and stimulate deacetylation. Glioblastoma multiforme (GBM) is the deadliest of malignant types of tumor in the central nervous system (CNS) and their biological features make treatment difficult. In the glioma microenvironment, infiltrating immune cells has been shown to possess beneficial effects for tumor progression. We analyzed SIRT1, CCL2, VCAM-1 and ICAM-1 in human glioma cell lines by immunoblotting. The correlation between those markers and clinico-pathological grade of glioma patients were assessed by the Gene Expression Omnibus (GEO) datasets analysis. We also used monocyte-binding assay to study the effects of melatonin on monocyte adhesion to GBM. Importantly, overexpression of SIRT1 by genetic modification or treatment of melatonin significantly downregulated the adhesion molecular VCAM-1 and ICAM-1 expression in GBM. CCL2-mediated monocyte adhesion and expression of VCAM-1 and ICAM-1 were regulated through SIRT1 signaling. SIRT1 is an important modulator of monocytes interaction with GBM that gives the possibility of improved therapies for GBM. Hence, this study provides a novel treatment strategy for the understanding of microenvironment changes in tumor progression.

Impact of p38γ mitogen-activated protein kinase (MAPK) on MDA-MB-231 breast cancer cells using metabolomic approach

BACKGROUND

The expression of p38 MAPK is high in breast cancer while its subunit p38γ had been rarely reported. We aimed to explain the effect of p38γ in breast cancer from the perspective of metabolomics.

METHODS

In this study, we detected the expression of p38γ in 28 breast carcinoma and para-tumor samples. Following MDA-MB-231 cell transfection with p38γ siRNAs and pc-DNA-3.1, cell viability, apoptosis, metastasis were determined through CCK-8, the cytometry analysis, transwell assay and wound healing assay. Finally, gas chromatograph-mass spectrometer (GC-MS) was used for analysis the differential metabolites.

RESULTS

The expression of p38γ was significantly up-regulated in breast cancer tissues. The transfection of si-p38γs could inhibit MDA-MB-231 cell propagation, metastasis, and induced cell apoptosis while overexpressed p38γ could promote the cell propagation, metastasis, and inhibit cell apoptosis. A total of 238 metabolites were identified and 72 of them differentially expressed in three groups (all P < 0.05, FDR < 0.05). Then the metabolites were enriched in the metabolism pathway, 85 pathways were included and 27 were significant (all P < 0.05, FDR < 0.05).

CONCLUSIONS

p38γ was up-regulated in breast cancer, which exerts a great influence on the cell growth, cell mobility, invasiveness, and apoptosis of MDA-MB-231 cells and also affected the metabolism.

Role of p38γ MAPK in regulation of EMT and cancer stem cells

p38γ is a member of p38 MAPK family which contains four isoforms p38α, p38β, p38γ, and p38δ. p38γ MAPK has unique function and is less investigated. Recent studies revealed that p38γ MAPK may be involved in tumorigenesis and cancer aggressiveness. However, the underlying cellular/molecular mechanisms remain unclear. Epithelial-mesenchymal transition (EMT) is a process that epithelial cancer cells transform to facilitate the loss of epithelial features and gain of mesenchymal phenotype. EMT promotes cancer cell progression and metastasis, and is involved in the regulation of cancer stem cells (CSCs) which have self-renewal capacity and are resistant to chemotherapy and target therapy. We showed that p38γ MAPK significantly increased EMT in breast cancer cells; over-expression of p38γ MAPK enhanced EMT while its down-regulation inhibited EMT. Meanwhile, p38γ MAPK augmented CSC population while knock down of p38γ MAPK decreased CSC ratio in breast cancer cells. MicroRNA-200b (miR-200b) was down-stream of p38γ MAPK and inhibited by p38γ MAPK; miR-200b mimics blocked p38γ MAPK-induced EMT while miR-200b inhibitors promoted EMT. p38γ MAPK regulated miR-200b through inhibiting GATA3. p38γ MAPK induced GATA3 ubiquitination, leading to its proteasome-dependent degradation. Suz12, a Polycomb group protein, was down-stream of miR-200b and involved in miR-200b regulation of EMT. Thus, our study established an important role of p38γ MAPK in EMT and identified a novel signaling pathway for p38γ MAPK-mediated tumor promotion.

Inhibition of p38 MAPK activity leads to cell type-specific effects on the molecular circadian clock and time-dependent reduction of glioma cell invasiveness

BACKGROUND

The circadian clock is the basis for biological time keeping in eukaryotic organisms. The clock mechanism relies on biochemical signaling pathways to detect environmental stimuli and to regulate the expression of clock-controlled genes throughout the body. MAPK signaling pathways function in both circadian input and output pathways in mammals depending on the tissue; however, little is known about the role of p38 MAPK, an established tumor suppressor, in the mammalian circadian system. Increased expression and activity of p38 MAPK is correlated with poor prognosis in cancer, including glioblastoma multiforme; however, the toxicity of p38 MAPK inhibitors limits their clinical use. Here, we test if timed application of the specific p38 MAPK inhibitor VX-745 reduces glioma cell invasive properties in vitro.

METHODS

The levels and rhythmic accumulation of active phosphorylated p38 MAPK in different cell lines were determined by western blots. Rhythmic luciferase activity from clock gene luciferase reporter cells lines was used to test the effect of p38 MAPK inhibition on clock properties as determined using the damped sine fit and Levenberg-Marquardt algorithm. Nonlinear regression and Akaike's information criteria were used to establish rhythmicity. Boyden chamber assays were used to measure glioma cell invasiveness following time-of-day-specific treatment with VX-745. Significant differences were established using t-tests.

RESULTS

We demonstrate the activity of p38 MAPK cycles under control of the clock in mouse fibroblast and SCN cell lines. The levels of phosphorylated p38 MAPK were significantly reduced in clock-deficient cells, indicating that the circadian clock plays an important role in activation of this pathway. Inhibition of p38 MAPK activity with VX-745 led to cell-type-specific period changes in the molecular clock. In addition, phosphorylated p38 MAPK levels were rhythmic in HA glial cells, and high and arrhythmic in invasive IM3 glioma cells. We show that inhibition of p38 MAPK activity in IM3 cells at the time of day when the levels are normally low in HA cells under control of the circadian clock, significantly reduced IM3 invasiveness.

CONCLUSIONS

Glioma treatment with p38 MAPK inhibitors may be more effective and less toxic if administered at the appropriate time of the day.

Evaluating the potential of circulating hTERT levels in glioma: can plasma levels serve as an independent prognostic marker?

Glioma is an aggressive primary Neuro-epithelial tumor with dismal prognosis, since there is a lack of molecular work-up during routine radiological monitoring of the disease. Currently, a number of potential molecular prognostic and predictive biomarkers are being characterized in line with structured diagnosis defined in World Health Organization guidelines 2016. Human-telomerase reverse-transcriptase (hTERT), a marker of proliferation and maintenance of genomic integrity has thus been investigated for its clinical relevance as an independent prognosticator in glioma. Expression of the protein in tumor tissue and in plasma of 72 diffuse glioma patients (astrocytoma) grade II-IV was determined and compared with relevant controls using immunofluorescence-immunohistochemistry and enzyme-linked immuno-sorbent assay. Appropriate statistical tests were applied to establish a correlation between on-site tumor and circulating levels of the marker and its independence of covariates. Expression of the marker in glioma tissues was significantly different from controls (p < 0.0001) and could discriminate within grades with ≥80% sensitivity. The tissue and plasma levels were positively associated with grades (r = 0.8845, p < 0.0001) and (r = 0.2834, p = 0.0158) respectively, while an inverse correlation with overall survival (r = -0.6558, p < 0.0001) and (r = -0.3941, p = 0.0006) respectively, was recorded. Plasma hTERT was significantly correlated with corresponding intra-tumor expression of hTERT (r = 0.2794, p = 0.0175). Multivariate Cox-regression identified plasma hTERT (p < 0.0005) as a prognostic factor; not associated with age, site or extent of resection (p > 0.05). This is the first experimental evidence for association of higher plasma levels of hTERT with overall survival in both low and high grade glioma.

p38γ and p38δ: From Spectators to Key Physiological Players

Although the physiological roles of p38γ and p38δ signalling pathways are largely unknown, new genetic and pharmacological tools are providing groundbreaking information on the function of these two stress-activated protein kinases. Recent studies show the importance of p38γ and p38δ in the regulation of processes as diverse as cytokine production, protein synthesis, exocytosis, cell migration, gene expression, and neuron activity, which have an acute impact on the development of pathologies related to inflammation, diabetes, neurodegeneration, and cancer. These recent breakthroughs are resolving some of the questions that have long been asked regarding the function of p38γ and p38δ in biology and pathology.

Unique case of oligoastrocytoma with recurrence and grade progression: Exhibiting differential expression of high mobility group-A1 and human telomerase reverse transcriptase

Mixed gliomas, primarily oligoastrocytomas, account for about 5%-10% of all gliomas. Distinguishing oligoastrocytoma based on histological features alone has limitations in predicting the exact biological behavior, necessitating ancillary markers for greater specificity. In this case report, human telomerase reverse transcriptase (hTERT) and high mobility group-A1 (HMGA1); markers of proliferation and stemness, have been quantitatively analyzed in formalin-fixed paraffin-embedded tissue samples of a 34 years old patient with oligoastrocytoma. Customized florescence-based immunohistochemistry protocol with enhanced sensitivity and specificity is used in the study. The patient presented with a history of generalized seizures and his magnetic resonance imaging scans revealed infiltrative ill-defined mass lesion with calcified foci within the left frontal white matter, suggestive of glioma. He was surgically treated at our center for four consecutive clinical events. Histopathologically, the tumor was identified as oligoastrocytoma-grade II followed by two recurrence events and final progression to grade III. Overall survival of the patient without adjuvant therapy was more than 9 years. Glial fibrillary acidic protein, p53, Ki-67, nuclear atypia index, pre-operative neutrophil-lymphocyte ratio, are the other parameters assessed. Findings suggest that hTERT and HMGA1 are linked to tumor recurrence and progression. Established markers can assist in defining precise histopathological grade in conjuction with conventional markers in clinical setup.

Combined deletion of p38γ and p38δ reduces skin inflammation and protects from carcinogenesis

The contribution of chronic skin inflammation to the development of squamous cell carcinoma (SCC) is poorly understood. While the mitogen-activated protein kinase p38α regulates inflammatory responses and tumour development, little is known about the role of p38γ and p38δ in these processes. Here we show that combined p38γ and p38δ (p38γ/δ) deletion blocked skin tumour development in a chemically induced carcinogenesis model. p38γ/δ deletion reduced TPA-induced epidermal hyperproliferation and inflammation; it inhibited expression of proinflammatory cytokines and chemokines in keratinocytes in vitro and in whole skin in vivo, resulting in decreased neutrophil recruitment to skin. Our data indicate that p38γ/δ in keratinocytes promote carcinogenesis by enabling formation of a proinflammatory microenvironment that fosters epidermal hyperproliferation and tumourigenesis. These findings provide genetic evidence that p38γ and p38δ have essential roles in skin tumour development, and suggest that targeting inflammation through p38γ/δ offers a therapeutic strategy for SCC treatment and prevention.

Clinicopathological significance of p38β, p38γ, and p38δ and its biological roles in esophageal squamous cell carcinoma

P38β, p38γ, and p38δ have been sporadically and scarcely reported to be involved in the carcinogenesis of cancers, compared with p38α isoform. However, little has been known regarding their clinicopathological significance and biological roles in esophageal squamous cell carcinoma (ESCC). Expression status of p38β, p38γ, and p38δ was assayed using immunohistochemistry with ESCC tissue microarray; ensuing clinicopathological significance was statistically analyzed. To define its biological roles on proliferation, migration and invasion of ESCC cell line Eca109 in vitro, MTT, wound healing, and Transwell assays were employed, respectively. As confirmation, athymic nude mice were taken to verify the effect over proliferation in vivo. It was found that both p38β and p38δ expression, other than p38γ, were significantly higher in ESCC tissues compared with paired normal controls. In terms of prognosis, only p38β expression was observed to be significantly associated with overall prognosis. Clinicopathologically, there was significant association between p38γ expression and clinical stage, lymph nodes metastases, and tumor volume. No significant association was found for p38β and p38δ between its expression and other clinicopathological parameters other than significant difference of expression between ESCC versus normal control. In Eca109, it was observed that p38β, p38γ, and p38δ can promote the cell growth and motility. As verification, over-expression of p38δ can promote, whereas knockdown of p38γ can prevent, the tumorigenesis in nude mice model xenografted with Eca109 cells whose basal level of p38δ was stably over-expressed and p38γ was stably knocked down. Together, our results demonstrate that p38β, p38γ, and p38δ played oncogenic roles in ESCC.

p38γ MAPK is required for inflammation-associated colon tumorigenesis

Chronic inflammation has long been considered to causatively link to colon cancer development. However, signal transduction pathways involved remain largely unidentified. Here, we report that p38γ mitogen-activated protein kinase mediates inflammatory signaling to promote colon tumorigenesis. Inflammation activates p38γ in mouse colon tissues and intestinal epithelial cell-specific p38γ knockout (KO) attenuates colitis and inhibits pro-inflammatory cytokine expression. Significantly, p38γ KO inhibits tumorigenesis in a colitis-associated mouse model. The specific p38γ pharmacological inhibitor pirfenidone also suppresses pro-inflammatory cytokine expression and colon tumorigenesis. The tumor-promoting activity of epithelial p38γ was further demonstrated by xenograft studies. In addition, p38γ is required for β-catenin/Wnt activities and p38γ stimulates Wnt transcription by phosphorylating β-catenin at Ser605. These results show that p38γ activation links inflammation and colon tumorigenesis. Targeting p38γ may be a novel strategy for colon cancer prevention and treatment.

Identification of a ternary protein-complex as a therapeutic target for K-Ras-dependent colon cancer

A cancer phenotype is driven by several proteins and targeting a cluster of functionally interdependent molecules should be more effective for therapeutic intervention. This is specifically important for Ras-dependent cancer, as mutated (MT) Ras is non-druggable and targeting its interaction with effectors may be essential for therapeutic intervention. Here, we report that a protein-complex activated by the Ras effector p38γ MAPK is a novel therapeutic target for K-Ras-dependent colon cancer. Unbiased proteomic screening and immune-precipitation analyses identified p38γ interaction with heat shock protein 90 (Hsp90) and K-Ras in K-Ras MT, but not wild-type (WT), colon cancer cells, indicating a role of this complex in Ras-dependent growth. Further experiments showed that this complex requires p38γ and Hsp90 activity to maintain MT, but not WT, K-Ras protein expression. Additional studies demonstrated that this complex is activated by p38γ-induced Hsp90 phosphorylation at S595, which is important for MT K-Ras stability and for K-Ras dependent growth. Of most important, pharmacologically inhibition of Hsp90 or p38γ activity disrupts the complex, decreases K-Ras expression, and selectively inhibits the growth of K-Ras MT colon cancer in vitro and in vivo. These results demonstrated that the p38γ-activated ternary complex is a novel therapeutic target for K-Ras-dependent colon cancer.