Prognostic significance of phosphorylated P38 mitogen-activated protein kinase and HER-2 expression in lymph node-positive breast carcinoma

Comprehensive analysis of MAPK genes in the prognosis, immune characteristics, and drug treatment of renal clear cell carcinoma using bioinformatic analysis and Mendelian randomization

Mitogen-activated protein kinase (MAPK) signalling is vitally important in tumour development and progression. This study is the first to comprehensively analyse the role of MAPK-family genes in the progression, prognosis, immune-cell infiltration, methylation, and potential therapeutic value drug candidates in ccRCC. We identified a novel prognostic panel of six MAPK-signature genes (MAP3K12, MAP3K1, MAP3K5, MAPK1, MAPK8, MAPK9), and introduced a robust MAPK-signature risk model for predicting ccRCC prognosis. Model construction, evaluation, and external validation using datasets from the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) database demonstrated its stability, as well as high sensitivity and specificity. Enrichment analysis suggested the participation of immune-mediated mechanism in MAPK dysregulation in ccRCC. Immune-infiltration analysis confirmed the relationship and revealed that the MAPK-signature risk model might stratify immunotherapy response in ccRCC, which was verified in drug sensitivity analysis and validated in external ccRCC immunotherapy dataset (GSE67501). Potential therapeutic drug predictions for key MAPKs using DSigDB, Network Analyst, CTD, and DGIdb were subsequently verified by molecular docking with AutoDock Vina and PyMol. Mendelian randomization further demonstrated the possibilities of the MAPK-signature genes as targets for therapeutic drugs in ccRCC. Methylation analysis using UALCAN and MethSurv revealed the participation of epigenetic modifications in dysregulation and survival difference of MAPK pathway in ccRCC. Among the key MAPKs, MAP3K12 exhibited the highest significance, indicating its independent prognostic value as single gene in ccRCC. Knockout and overexpression validation experiments in vitro and in vivo found that MAP3K12 acted as a promoter of tumour progression in RCC, suggesting a pivotal role for MAP3K12 in the proliferation, migration, and invasion of RCC cells. Our findings proposed the potential of MAPK-signature genes as biomarkers for prognosis and therapy response, as well as targets for therapeutic drugs in ccRCC.

Targeting ARNT attenuates chemoresistance through destabilizing p38α-MAPK signaling in glioblastoma

Glioblastoma (GBM) is the most aggressive and lethal brain tumor in adults. This study aimed to investigate the functional significance of aryl hydrocarbon receptor nuclear translocator (ARNT) in the pathogenesis of GBM. Analysis of public datasets revealed ARNT is upregulated in GBM tissues compared to lower grade gliomas or normal brain tissues. Higher ARNT expression correlated with the mesenchymal subtype and poorer survival in GBM patients. Silencing ARNT using lentiviral shRNAs attenuated the proliferative, invasive, and stem-like capabilities of GBM cell lines, while ARNT overexpression enhanced these malignant phenotypes. Single-cell RNA sequencing uncovered that ARNT is highly expressed in a stem-like subpopulation and is involved in regulating glycolysis, hypoxia response, and stress pathways. Mechanistic studies found ARNT activates p38 mitogen-activated protein kinase (MAPK) signaling to promote chemoresistance in GBM cells. Disrupting the ARNT/p38α protein interaction via the ARNT PAS-A domain restored temozolomide sensitivity. Overall, this study demonstrates ARNT functions as an oncogenic driver in GBM pathogenesis and represents a promising therapeutic target.

Suppressing MTERF3 inhibits proliferation of human hepatocellular carcinoma via ROS-mediated p38 MAPK activation

Mitochondrial transcription termination factor 3 (MTERF3) negatively regulates mitochondrial DNA transcription. However, its role in hepatocellular carcinoma (HCC) progression remains elusive. Here, we investigate the expression and function of MTERF3 in HCC. MTERF3 is overexpressed in HCC tumor tissues and higher expression of MTERF3 positively correlates with poor overall survival of HCC patients. Knockdown of MTERF3 induces mitochondrial dysfunction, S-G2/M cell cycle arrest and apoptosis, resulting in cell proliferation inhibition. In contrast, overexpression of MTERF3 promotes cell cycle progression and cell proliferation. Mechanistically, mitochondrial dysfunction induced by MTERF3 knockdown promotes ROS accumulation, activating p38 MAPK signaling pathway to suppress HCC cell proliferation. In conclusion, ROS accumulation induced by MTERF3 knockdown inhibits HCC cell proliferation via p38 MAPK signaling pathway suggesting a promising target in HCC patients.

Transcriptome of Lung Cancer Cells Resistant to the Cytotoxic Activity of Macrophages

The role of the immune system in tumor progression has been the subject of research for more than 100 years since Paul Ehrlich hypothesized that the presence of the immune system limits the occurrence of cancer. One of the mechanisms hindering the initiation and progression of the tumor is the cytotoxic activity of macrophages; however, in some cases, it is not sufficient to control tumorigenesis. This may be due to both the development of resistance of tumor cells to the antitumor activity of macrophages and the development of a tolerant phenotype of macrophages that do not have sufficient antitumor activity. In this work, the lung cancer cells resistant to the cytotoxic action of macrophages were obtained and characterized for the first time, and the genes associated with the observed changes were identified. Understanding the mechanisms of resistance of tumor cells to the cytotoxic activity of macrophages and the peculiarities of its manifestation in a tumor environment is critically important for improving the effectiveness of the existing methods of cancer treatment and developing novel methods for tumor immunotherapy.

Effects of thiostrepton alone or in combination with selumetinib on triple-negative breast cancer metastasis

OBJECTIVE

FoxM1 transcription factor contributes to tumor metastasis and poor prognosis in many cancers including triple-negative breast cancer (TNBC). In this study, we examined the effects of FoxM1 inhibitor Thiostrepton (THIO) alone or in combination with MEK inhibitor Selumetinib (SEL) on metastatic parameters in vitro and in vivo.

METHODS

Cell viability was determined by MTT assay. Immunoblotting and immunohistochemistry was used to assess metastasis-related protein expressions in 4T1 cells and its allograft tumor model in BALB/c mice. In vivo uPA activity was determined by enzymatic methods.

RESULTS

Both inhibitors were effective on the expressions of FoxM1, ERK, p-ERK, Twist, E-cadherin, and Vimentin alone or in combination in vitro. THIO significantly decreased 4T1 cell migration and changed the cell morphology from mesenchymal-like to epithelial-like structure. THIO was more effective than in combination with SEL in terms of metastatic protein expressions in vivo. THIO alone significantly inhibited mean tumor growth, decreased lung metastasis rate and tumor foci, however, no significant changes in these parameters were observed in the combined group. Immunohistochemically, FoxM1 expression intensity was decreased with THIO and its combination with SEL in the tumors.

CONCLUSIONS

This study suggests that inhibiting FoxM1 as a single target is more effective than combined treatment with MEK in theTNBC allograft model. The therapeutic efficacy of THIO should be investigated with further studies on appropriate drug delivery systems.

GFAT1-linked TAB1 glutamylation sustains p38 MAPK activation and promotes lung cancer cell survival under glucose starvation

Reprogrammed cell metabolism is deemed as one of the hallmarks of cancer. Hexosamine biosynthesis pathway (HBP) acts as an “energy sensor” in cells to regulate metabolic fluxes. Glutamine-fructose-6-phosphate amidotransferase 1 (GFAT1), the rate-limiting enzyme of HBP, is broadly found with elevated expression in human cancers though its exact and concrete role in tumorigenesis still remains unknown and needs further investigation. P38 mitogen-activated protein kinase (MAPK) is an important component of stress-signaling pathway and plays a critical role in cell fate decision, whereas the underlying mechanism of its activation under nutrient stress also remains elusive. In this study, we show that glucose deprivation induces the interaction of GFAT1 with transforming growth factor β-activated kinase 1 binding protein 1 (TAB1) in a TAB1 S438 phosphorylation-dependent manner. Subsequently, the binding of GFAT1 to TAB1 facilitates TTLL5–GFAT1–TAB1 complex formation, and the metabolic activity of GFAT1 for glutamate production further contributes to TTLL5-mediated TAB1 glutamylation. In consequence, TAB1 glutamylation promotes the recruitment of p38α MAPK and thus drives p38 MAPK activation. Physiologically, GFAT1-TAB1-p38 signaling promotes autophagy occurrence and thus protects tumor cell survival under glucose deficiency. Clinical analysis indicates that both GFAT1 and TAB1 S438 phosphorylation levels correlate with the poor prognosis of lung adenocarcinoma patients. These findings altogether uncover an unidentified mechanism underlying p38 MAPK signaling regulation by metabolic enzyme upon nutrient stress and provide theoretical rationality of targeting GFAT1 for cancer treatment.

Associations of genetic susceptibility to 16 cancers with risk of breast cancer overall and by intrinsic subtypes

Certain genetic variants are associated with risks of multiple cancers. We investigated breast cancer risk with overall genetic susceptibility to each of 16 other cancers. We constructed polygenic risk scores (PRS) for 16 cancers using risk variants identified by genome-wide association studies. We evaluated the associations of these PRSs with breast cancer risk (overall and by subtypes) using Breast Cancer Association Consortium data, including 106,278 cases and 91,477 controls of European ancestry. Odds ratios (OR) and 95% confidence intervals (CIs) were estimated to measure the association of each PRS with breast cancer risk. Data from the UK Biobank, including 4,337 cases and 209,983 non-cases, were used to replicate the findings. A 5%–8% significantly elevated risk of overall breast cancer was associated with per unit increase of the PRS for glioma and cancers of the corpus uteri, stomach, or colorectum. Analyses by subtype revealed that the PRS for corpus uteri cancer (OR = 1.09; 95% CI, 1.03–1.15) and stomach cancer (OR = 1.07; 95% CI, 1.03–1.12) were associated with estrogen receptor-positive breast cancer, while ovarian cancer PRS was associated with triple-negative breast cancer (OR = 1.25; 95% CI, 1.01–1.55). UK Biobank data supported the positive associations of overall breast cancer risk with PRS for melanoma and cancers of the stomach, colorectum, and ovary. Our study provides strong evidence for shared genetic susceptibility of breast cancer with several other cancers. Results from our study help uncover the genetic basis for breast and other cancers and identify individuals at high risk for multiple cancers.

Effects of radiofrequency radiation on colorectal cancer cell proliferation and inflammation

Objectives

The aim of this study is to investigate the effects of radiofrequency radiation (RFR) on apoptosis, proliferation, stress response, and inflammation markers in colorectal cancer cells.

Methods

We tested the effects of intermittent exposure to RFR at different frequencies on two different colorectal cancer cell lines; HCT-116 and DLD-1. Protein levels were subsequently analyzed by ELISA.

Results

RFR led to a decrease in P53, p-P53, p-P38, and p-IkB levels in HCT-116 cells, while leading to an increase in BAD, p-BAD, p-STAT3,NF-κB levels. Two thousand one hundred Megahertz of RFR altered the P53, BAD, and NF-ΚB expression in HCT-116 cells. P53, p-P53, BAD, p-BAD, NF-κB, p-NF-κB, p-P38, p-SAPK/JNK, p-STAT3, and p-IkB levels increased after exposure to RFR at 900 and 2,100 MHz in DLD-1 cells. Unlike HCT-116 cells, 1,800 MHz of RFR was reported to have no effect on DLD1 cells.

Conclusions

RFR increased apoptosis and inflammatory response in HCT116 cells, while lowering the active P38 and active P53 levels, which are indicators of poor prognosis in several cancers. Genetic differences, such as P53 mutation (DLD-1), are critical to the cell response to RFR, which explains the reason why scientific studies on the effects of RFR yield contradictory results.

Exposure to per- and polyfluoroalkyl substances and premature skin aging

Per- and polyfluoroalkyl substances (PFASs) are a ubiquitous group of persistent chemicals distributed globally in the environment. Skin aging is a notorious process that is prematurely induced by the interaction between endogenous and exogenous factors, including exposure to environmental chemicals. The existing evidence suggests that skin absorption of PFASs through dermal contact may be an important route of exposure to these chemicals in humans. On the other hand, PFASs intake by other routes may lead to PFASs bioaccumulation in the skin via tissue bio-distribution. Additionally, the presence of PFASs in consumer and cosmetic products combined with their daily close contact with the skin could render humans readily susceptible to dermal absorption. Therefore, chronic low-dose dermal exposure to PFASs can occur in the human population, representing another important route of exposure to these chemicals. Studies indicate that PFASs can threaten skin health and contribute to premature skin aging. Initiation of inflammatory-oxidative cascades, induction of DNA damage such as telomere shortening, dysregulation of genes engaged in dermal barrier integrity and its functions, signaling of the mitogen activated protein kinase (MAPK) pathway, and last but not least the down-regulation of extracellular matrix (ECM) components are among the most likely mechanisms by which PFASs can contribute to premature skin aging.

Identification of the anti-breast cancer targets of triterpenoids in Liquidambaris Fructus and the hints for its traditional applications

BACKGROUND

Liquidambaris Fructus is the infructescences of Liquidambar formosana Hance and it has been used to treat some breast disease in Traditional Chinese Medicine. In the previous study we found the anti-breast cancer effect of triterpenoid in Liquidambaris Fructus. This study is a further investigation of the triterpenoids in Liquidambaris Fructus and aims to identify their anti-breast cancer targets, meanwhile, to estimate the rationality of the traditional applications of Liquidambaris Fructus.

METHODS

Triterpenoids in Liquidambaris Fructus were isolated and their structures were identified by NMR spectrums. Potential targets of these triterpenoids were predicted using a reverse pharmacophore mapping strategy. Associations between these targets and the therapeutic targets of breast cancer were analyzed by constructing protein-protein interaction network, and targets played important roles in the network were identified using Molecular Complex Detection method. Binding affinity between the targets and triterpenoids was studied using molecular docking method. Gene ontology enrichment analysis was conducted to reveal the biological process and signaling pathways that the identified targets were involved in.

RESULTS

Thirteen triterpenoids were identified and 6 of them were the first time isolated from Liquidambaris Fructus. Predicted ADME properties revealed a good druggability of these triterpenoids. We identified 18 protein targets which were closely related to breast cancer progression, especially triple-negative, basal-like or advanced stage breast cancers. The triterpenoids could bind with these targets as their inhibitors: hydrophobic skeleton is a favorable factor for them to stabilize at binding site and polar C17- or C3- substituent was necessary for binding. GO enrichment analysis indicated that inhibition of protein tyrosine kinases autophosphorylation might be the primary mechanism for the anti-breast cancer effect of the triterpenoids, and ErbB4 and EGFR were the most relevant targets.

CONCLUSIONS

The study revealed that triterpenoids from Liquidambaris Fructus might exert anti-breast cancer effect by directly inhibit multiple protein targets and signaling pathways, especially ErbB4 and EGFR and related pathways. This study also brings up another hint that the traditional applications of Liquidambaris Fructus on hypogalactia should be reassessed systematically because it might suppress rather than promote lactation by inhibiting the activity of ErbB4.

CDK4/6 and MAPK-Crosstalk as Opportunity for Cancer Treatment

Despite the development of targeted therapies and novel inhibitors, cancer remains an undefeated disease. Resistance mechanisms arise quickly and alternative treatment options are urgently required, which may be partially met by drug combinations. Protein kinases as signaling switchboards are frequently deregulated in cancer and signify vulnerable nodes and potential therapeutic targets. We here focus on the cell cycle kinase CDK6 and on the MAPK pathway and on their interplay. We also provide an overview on clinical studies examining the effects of combinational treatments currently explored for several cancer types.

NRASQ61K melanoma tumor formation is reduced by p38-MAPK14 activation in zebrafish models and NRAS-mutated human melanoma cells

Oncogenic BRAF and NRAS mutations drive human melanoma initiation. We used transgenic zebrafish to model NRAS-mutant melanoma, and the rapid tumor onset allowed us to study candidate tumor suppressors. We identified P38α-MAPK14 as a potential tumor suppressor in The Cancer Genome Atlas melanoma cohort of NRAS-mutant melanomas, and overexpression significantly increased the time to tumor onset in transgenic zebrafish with NRAS-driven melanoma. Pharmacological activation of P38α-MAPK14 using anisomycin reduced in vitro viability of melanoma cultures, which we confirmed by stable overexpression of p38α. We observed that the viability of MEK inhibitor resistant melanoma cells could be reduced by combined treatment of anisomycin and MEK inhibition. Our study demonstrates that activating the p38α-MAPK14 pathway in the presence of oncogenic NRAS abrogates melanoma in vitro and in vivo. SIGNIFICANCE: The significance of our study is in the accountability of NRAS mutations in melanoma. We demonstrate here that activation of p38α-MAPK14 pathway can abrogate NRAS-mutant melanoma which is contrary to the previously published role of p38α-MAPK14 pathway in BRAF mutant melanoma. These results implicate that BRAF and NRAS-mutant melanoma may not be identical biologically. We also demonstrate the translational benefit of our study by using a small molecule compound-anisomycin (already in use for other diseases in clinical trials) to activate p38α-MAPK14 pathway.

Anti-Cancer Effects of 3, 3'-Diindolylmethane on Human Hepatocellular Carcinoma Cells Is Enhanced by Calcium Ionophore: The Role of Cytosolic Ca2+ and p38 MAPK

Purpose: 3,3'-Diindolylmethane (DIM), derived from indole-3-carbinol (I3C) in the Brassica species of cruciferous vegetables, has anticancer effects, but its exact underlying mechanism of action is unknown. We explored the roles of cytosolic free calcium ([Ca2+]i) and p38 MAPK in the anti-cancer effects of DIM in human hepatocellular carcinoma cells. Methods: Cell proliferation was measured with a Cell Counting Kit-8 (CCK-8) and the clonogenic formation assay. Cell apoptosis was examined by flow cytometric analysis and Hoechst dye staining. Cleaved-caspase3, cleaved-PARP, Bax, total, and phosphorylated p38 MAPK were assayed by western blotting. [Ca2+]i was measured with Fluo-3/AM by fluorescence microscopy. A23187, a calcium ionophore, was used to increase [Ca2+]i levels. Results: DIM inhibited cell proliferation in both SMMC-7721 and HepG2 cells in a concentration- and time-dependent manner. DIM also enhanced phosphorylation of p38 MAPK (p-p38), which was attenuated by SB203580. The proliferation inhibition and apoptosis induction by DIM were also blunted. In addition, DIM increased [Ca2+]i in HCC cells, and this effect was inhibited by the calcium chelator, BAPTA-AM, resulting in reduced p-p38 MAPK activation and apoptosis in DIM-treated cells, though the proliferation inhibition by DIM was unchanged. However, the DIM-induced cell proliferation inhibition and apoptosis were significantly enhanced by A23187, a selective calcium ionophore, which was attributed to exaggerated p-p38 MAPK. Conclusions: The calcium ionophore enhanced DIM-induced anti-cancer effects in hepatocellular carcinoma cells, secondary to [Ca2+]i-dependent activation of p38 MAPK. Treatment with a combination of DIM and calcium ionophore may offer a new approach to enhance the chemotherapeutic efficacy in liver cancer.

A Ruthenium(II) N-Heterocyclic Carbene (NHC) Complex with Naphthalimide Ligand Triggers Apoptosis in Colorectal Cancer Cells via Activating the ROS-p38 MAPK Pathway

The p38 MAPK pathway is known to influence the anti-tumor effects of several chemotherapeutics, including that of organometallic drugs. Previous studies have demonstrated the important role of p38 both as a regulator and a sensor of cellular reactive oxygen species (ROS) levels. Investigating the anti-cancer properties of novel 1,8-naphthalimide derivatives containing Rh(I) and Ru(II) N-heterocyclic carbene (NHC) ligands, we observed a profound induction of ROS by the complexes, which is most likely generated from mitochondria (mtROS). Further analyses revealed a rapid and consistent activation of p38 signaling by the naphthalimide-NHC conjugates, with the Ru(II) analogue—termed MC6—showing the strongest effect. In view of this, genetic as well as pharmacological inhibition of p38α, attenuated the anti-proliferative and pro-apoptotic effects of MC6 in HCT116 colon cancer cells, highlighting the involvement of this signaling molecule in the compound’s toxicity. Furthermore, the influence of MC6 on p38 signaling appeared to be dependent on ROS levels as treatment with general- and mitochondria-targeted anti-oxidants abrogated p38 activation in response to MC6 as well as the molecule’s cytotoxic- and apoptogenic response in HCT116 cells. Altogether, our results provide new insight into the molecular mechanisms of naphthalimide-metal NHC analogues via the ROS-induced activation of p38 MAPK, which may have therapeutic interest for the treatment of various cancer types.

Nephronectin mediates p38 MAPK-induced cell viability via its integrin-binding enhancer motif

Nephronectin (NPNT) is an extracellular matrix (ECM) protein involved in kidney development. We recently reported intracellular NPNT as a potential prognostic marker in breast cancer and that NPNT promotes metastasis in an integrin-dependent manner. Here, we used reverse-phase protein array (RPPA) to analyze NPNT-triggered intracellular signaling in the 66cl4 mouse breast cancer cell line. The results showed that the integrin-binding enhancer motif is important for the cellular effects upon NPNT interaction with its receptors, including phosphorylation of p38 mitogen-activated protein kinase (MAPK). Furthermore, analysis using prediction tools suggests involvement of NPNT in promoting cell viability. In conclusion, our results indicate that NPNT, via its integrin-binding motifs, promotes cell viability through phosphorylation of p38 MAPK.

Gossypetin is a novel MKK3 and MKK6 inhibitor that suppresses esophageal cancer growth in vitro and in vivo

Gossypetin as a hexahydroxylated flavonoid found in many flowers and Hibiscus. It exerts various pharmacological activities, including antioxidant, antibacterial and anticancer activities. However, the anticancer capacity of gossypetin has not been fully elucidated. In this study, gossypetin was found to inhibit anchorage-dependent and -independent growth of esophageal cancer cells. To identify the molecular target(s) of gossypetin, various signaling protein kinases were screened and results indicate that gossypetin strongly attenuates the MKK3/6-p38 signaling pathway by directly inhibiting MKK3 and MKK6 protein kinase activity in vitro. Mechanistic investigations showed that arginine-61 in MKK6 is critical for binding with gossypetin. Additionally, the inhibition of cell growth by gossypetin is dependent on the expression of MKK3 and MKK6. Gossypetin caused G2 phase cell cycle arrest and induced intrinsic apoptosis by activating caspases 3 and 7 and increasing the expression of BAX and cytochrome c. Notably, gossypetin suppressed patient-derived esophageal xenograft tumor growth in an in vivo mouse model. Our findings suggest that gossypetin is an MKK3 and MKK6 inhibitor that could be useful for preventing or treating esophageal cancer.

Co-expression of nuclear P38 and hormone receptors is prognostic of good long-term clinical outcome in primary breast cancer and is linked to upregulation of DNA repair

Background

P38 mitogen activated protein kinase is an intermediary signal transduction factor with context-specific roles in breast cancer. Recent mechanistic studies add to the growing consensus that P38 is a tumour suppressor, and it may represent a novel target for breast cancer treatment. The aim of this study is to add definitive data on the prognostic value of P38 and its link with biomarkers in primary breast cancer.

Methods

A large, well-characterised series of 1332 primary breast cancer patients with long-term clinical follow-up was assessed for P38 expression by immunohistochemistry. Association of clinicopathological factors and a panel of breast cancer biomarkers was determined by chi-squared test, and multivariate survival analysis was performed using Cox Proportional Hazards regression modelling.

Results

This study shows that nuclear P38 is co-expressed with nuclear hormone receptors (p < 0.001) and is an independent prognostic marker of good long-term clinical outcome in primary breast cancer (hazard ratio 0.796, 95% confidence interval 0.662–0.957, p = 0.015). Significant association was found between expression of P38 and markers of DNA repair including nuclear BRCA1 and RAD51, and cleaved PARP1 (all p < 0.001).

Conclusions

The findings support the proposed role for P38 as a tumour suppressor in breast cancer via upregulation of DNA repair proteins and provide novel hypothesis-generating information on the potential role of P38 in adjuvant therapy decision making.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4924-2) contains supplementary material, which is available to authorized users.

Id4 promotes cisplatin resistance in lung cancer through the p38 MAPK pathway

Inhibitor of differentiation 4 (Id4) plays an important role in tumorigenesis, but its role in cancer chemoresistance remains unclear. Our study showed that Id4 expression in cisplatin-resistant A549/DDP cells was higher than that in parental A549 cells. Moreover, overexpression of Id4 in A549 cells results in cisplatin resistance and apoptosis inhibition, while increasing the IC50 for cisplatin through activation of phospho-p38 MAPK. However, Id4 knockdown in A549/DDP cells was shown to resensitize A549/DDP cells to cisplatin and induce apoptosis, as well as decrease the IC50 for cisplatin through inactivation of phospho-p38 MAPK. In addition, a p38 MAPK inhibitor (SB202190) could partly reverse both Id4-reduced apoptosis and Id4-induced cisplatin resistance. These results suggest that Id4 inhibits cisplatin-induced apoptosis in human lung adenocarcinoma, partially through activation of the p38 MAPK pathway. Our research indicates that Id4 may be a new target for non-small-cell lung cancer treatment.

Expression and prognostic value of HER-2/neu in primary breast cancer with sentinel lymph node metastasis

The present study explores the correlation of human epidermal growth factor receptor-2 (HER-2) protein expression with sentinel lymph node (SLN) metastasis and prognosis of breast cancer. The breast cancer tissues and adjacent tissues were obtained from patients with primary breast cancer. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to detect the mRNA level of HER-2. Spearman correlation analysis was used to analyze the correlation of HER-2 expression with SLN metastasis. The disease-free survival (DFS) and overall survival (OS) of breast cancer patients were investigated. Univariate and multivariate analyses were performed to explore factors influencing SLN metastasis and prognosis of breast cancer. Compared with adjacent tissues, HER-2 expression was significantly up-regulated in breast cancer tissues. HER-2 expression was correlated with the pathological type, tumor node metastasis (TNM) staging, histological grade, blood vessel invasion, SLN metastasis, estrogen receptor (ER), and progesterone receptor (PR). The expression level of HER-2 was positively related to the SLN metastasis (r=0.548). Median DFS and OS were longer in patients with negative HER-2 expression than in patients with positive HER-2 expression. TNM staging, SLN metastasis, and expression levels of HER-2 and ER were independent factors for DFS of breast cancer patients, while TNM staging, blood vessel invasion, histological grade, SLN metastasis, and expression levels of HER-2 and PR were independent factors for OS of breast cancer patients. Our study suggests that high expression of HER-2 promoted SLN metastasis. HER-2 expression and SLN metastasis were the independent factors for the prognosis of breast cancer.

Osteoprotegerin mediates tumor-promoting effects of Interleukin-1beta in breast cancer cells

Background

It is widely recognized that inflammation promotes breast cancer invasion and metastasis. Given the complex nature of the breast tumor inflammatory microenvironment, much remains to be understood of the molecular mechanisms that govern these effects. We have previously shown that osteoprotegerin knockdown in breast cancer cells resulted in reduced invasion and metastasis. Here we present novel insight into the role of osteoprotegerin in inflammation-driven tumor progression in breast cancer by investigating the link between osteoprotegerin, macrophages and the potent pro-inflammatory cytokine Interleukin-1beta.

Methods

We used human breast cancer cell lines to investigate the effects of Interleukin-1beta treatment on osteoprotegerin secretion as measured by ELISA. We analyzed public datasets containing human breast cancer genome-wide mRNA expression data to reveal a significant and positive correlation between osteoprotegerin mRNA expression and the mRNA expression of Interleukin-1beta and of monocyte chemoattractant protein CC-chemokine ligand 2. Osteoprotegerin, Interleukin-1beta and CC-chemokine ligand 2 mRNA levels were also examined by qPCR on cDNA from normal and cancerous human breast tissue. We determined the effect of Interleukin-1beta–producing macrophages on osteoprotegerin expression by co-culturing breast cancer cells and differentiated THP-1 macrophages. Immunohistochemistry was performed on human breast tumor tissue microarrays to assess macrophage infiltration and osteoprotegerin expression. To demonstrate that osteoprotegerin mediated functional effects of Interleukin-1beta we performed cell invasion studies with control and OPG siRNA knockdown on Interleukin-1beta-treated breast cancer cells.

Results

We report that Interleukin-1beta induces osteoprotegerin secretion, independent of breast cancer subtype and basal osteoprotegerin levels. Co-culture of breast cancer cells with Interleukin-1beta-secreting macrophages resulted in a similar increase in osteoprotegerin secretion in breast cancer cells as Interleukin-1beta treatment. Macrophage infiltration correlates with osteoprotegerin secretion in human breast tumor tissue samples. We show that osteoprotegerin secretion is regulated by Interleukin-1beta in a p38- and p42/44-dependent manner. We also demonstrate that osteoprotegerin knockdown represses Interleukin-1beta expression, Interleukin-1beta-mediated breast cancer cell invasion and MMP3 expression.

Conclusions

These data indicate a novel role for osteoprotegerin as a mediator of inflammation- promoted breast cancer progression.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-017-0606-y) contains supplementary material, which is available to authorized users.

Alcohol promotes migration and invasion of triple-negative breast cancer cells through activation of p38 MAPK and JNK

Although alcohol is an established breast cancer risk factor, the underlying mechanisms remain unclear. Previous studies examined the general association between alcohol consumption and breast cancer risk; however, the risk for different breast cancer subtypes has been rarely reported. Triple-negative breast cancer (TNBC) is a subtype of breast cancer lacking hormone receptors and HER2 expression, and having poor prognosis. Understanding the molecular mechanisms of TNBC etiology remains a significant challenge. In this study, we investigated cellular responses to alcohol in two TNBC cell lines, MDA-MB-231 and MDA-MB-468. Our results showed that alcohol at low concentrations (0.025-0.1% v/v) induced cell proliferation, migration, and invasion in 1% FBS-containing medium. Molecular analysis indicated that these phenotypic changes were associated with alcohol-induced reactive oxygen species production and increased p38 and JNK phosphorylation. Likewise, p38 or JNK inhibition attenuated alcohol-induced cell migration and invasion. We revealed that alcohol treatment activated/phosphorylated NF-κB regulators and increased transcription of NF-κB-targeted genes. While examining the role of acetaldehyde, the major alcohol metabolite, in alcohol-associated responses in TNBC cells, we saw that acetaldehyde induced cell migration, invasion, and increased phospho-p38, phospho-JNK, and phospho-IκBα in a pattern similar to alcohol treatment. Taken together, we established that alcohol promotes TNBC cell proliferation, migration, and invasion in vitro. The underlying mechanisms involve the induction of oxidative stress and the activation of NF-κB signaling. In particular, the activation of p38 and JNK plays a pivotal role in alcohol-induced cellular responses. These results will advance our understanding of alcohol-mediated development and promotion of TNBC. © 2016 Wiley Periodicals, Inc.

Activation of Epidermal Growth Factor Receptor/p38/Hypoxia-inducible Factor-1α Is Pivotal for Angiogenesis and Tumorigenesis of Malignantly Transformed Cells Induced by Hexavalent Chromium

Hexavalent chromium (Cr(VI))-containing compounds are well established environmental carcinogens. Most mechanistic investigations of Cr(VI)-induced carcinogenesis focus on oxidative stress and various cellular responses, leading to malignant cell transformation or the first stage of metal-induced carcinogenesis. The development of malignantly transformed cells into tumors that require angiogenesis is the second stage. This study focuses on the second stage, in particular, the role of EGF receptor (EGFR) signaling in angiogenesis and tumorigenesis of Cr(VI)-transformed cells. Our preliminary studies have shown that EGFR is constitutively activated in Cr(VI)-transformed cells, in lung tissue from Cr(VI)-exposed animals, and in lung tumor tissue from a non-smoking worker occupationally exposed to Cr(VI) for 19 years. Using in vitro and in vivo models, the present study has investigated the role of EGFR in angiogenesis of Cr(VI)-transformed cells. The results show that Cr(VI)-transformed cells are angiogenic. Hypoxia-inducible factor-1α, pro-angiogenic protein matrix metalloproteinase 1, and VEGF are all highly expressed in Cr(VI)-transformed cells, in lung tissue from animals exposed to Cr(VI), and in lung tumor tissue from a non-smoking worker occupationally exposed to Cr(VI) for 19 years. p38 MAPK is also activated in Cr(VI)-transformed cells and in human lung tumor tissue. Inhibition of EGFR reduces p38 MAPK, resulting in decreased expression of hypoxia-inducible factor-1α, metalloproteinase 1, and VEGF, leading to suppressions of angiogenesis and tumorigenesis. Overall, the present study has demonstrated that EGFR plays an important role in angiogenesis and tumorigenesis of Cr(VI)-transformed cells.

Phosphorylated-p38 mitogen-activated protein kinase expression is associated with clinical factors in invasive breast cancer

Purpose

P38 mitogen-activated protein kinases (MAPK) level is an important prognostic factor in breast cancer. This study was performed to detect the expressions of P-p38 MAPK expression in breast cancer and explore their correlations with clinicopathological factors.

Experimental design

Tumor samples from 355 Chinese patients diagnosed with invasive breast cancer and adjacent non-cancerous tissue were collected between 2003 and 2010. The expression of P-p38 MAPK was analyzed using immunohistochemical staining. The correlations between P-p38 MAPK expression and clinicopathological findings including age, AJCC Stage, Histologic characters, ER, PR, and HER2 were analyzed using the parametric correlation method. P-p38 MAPK was selected as dependent variable to perform multivariate analysis respectively at last.

Results

Overall, 161 (45 %) and 183 (52 %) of the 355 specimens showed positive P-p38 MAPK staining in the cytoplasm and nucleus respectively, which were significant higher than that in the adjacent non-cancerous tissues in both the cytoplasm and the nucleus. High P-p38 MAPK expression of cytoplasm and nucleus were both associated with positive PR status in luminal A/B type of breast cancer, and were both associated with positive HER2 status in HER2-positive type of breast cancer. The result of multivariate analysis demonstrated that HER2 and PR were both significantly association with P-p38 MAPK expression of cytoplasm and nucleus.

Conclusions

Our study suggests that P-p38 MAPK expression were significantly associated with clinicopathological factors and PR/HER2 might association with phosphorylation of p38 MAPK in different types of breast cancer.

Proline isomerisation as a novel regulatory mechanism for p38MAPK activation and functions

The stress-induced p38 mitogen-activated protein kinase (MAPK) pathway plays an essential role in multiple physiological processes, including cancer. In turn, p38MAPK phosphorylation at Thr180 and Tyr182 is a key regulatory mechanism for its activation and functions. Here we show that this mechanism is actively regulated through isomerisation of Pro224. Different cyclophilins can isomerise this proline residue and modulate the ability of upstream kinases to phosphorylate Thr180 and Tyr182. In vivo mutation of Pro224 to Ile in endogenous p38MAPK significantly reduced its phosphorylation and activity. This resulted in attenuation of p38MAPK signalling, which in turn caused an enhanced apoptosis and sensitivity to a DNA-damaging drug, cisplatin. We further found a reduction in size and number of lesions in homozygous mice carrying the p38MAPK P224I substitution in a K-ras model of lung tumorigenesis. We propose that cyclophilin-dependent isomerisation of p38MAPK is an important novel mechanism in regulating p38MAPK phosphorylation and functions. Thus, inhibition of this process, including with drugs that are in clinical trials, may improve the efficacy of current anti-cancer therapeutic regimes.

MEK2 controls the activation of MKK3/MKK6-p38 axis involved in the MDA-MB-231 breast cancer cell survival: Correlation with cyclin D1 expression

The Ras-Raf-MEK-ERK1/2 signaling pathway regulates fundamental processes in malignant cells. However, the exact contributions of MEK1 and MEK2 to the development of cancer remain to be established. We studied the effects of MEK small-molecule inhibitors (PD98059 and U0126) and MEK1 and MEK2 knock-down on cell proliferation, apoptosis and MAPK activation. We showed a diminution of cell viability that was associated with a downregulation of cyclin D1 expression and an increase of apoptosis marker in MEK2 silenced cells; by contrast, a slight increase of cell survival was observed in the absence of MEK1 that correlated with an augment of cyclin D1 expression. These data indicate that MEK2 but not MEK1 is essential for MDA-MB-231 cell survival. Importantly, the role of MEK2 in cell survival appeared independent on ERK1/2 phosphorylation since its absence did not alter the level of activated ERK1/2. Indeed, we have reported an unrevealed link between MEK2 and MKK3/MKK6-p38 MAPK axis where MEK2 was essential for the phosphorylation of MKK3/MKK6 and p38 MAPK that directly impacted on cyclin D1 expression. Importantly, the MEK1 inhibitor PD98059, like MEK1 silencing, induced an augment of cyclin D1 expression that correlated with an increase of MDA-MB-231 cell proliferation suggesting that MEK1 may play a regulatory role in these cells. In sum, the crucial role of MEK2 in MDA-MB-231 cell viability and the unknown relationship between MEK2 and MKK3/MKK6-p38 axis here revealed may open new therapeutic strategies for aggressive breast cancer.

Modifications to glucocorticoid and progesterone receptors alter cell fate in breast cancer

Steroid hormone receptors (SRs) are heavily posttranslationally modified by the reversible addition of a variety of molecular moieties, including phosphorylation, acetylation, methylation, SUMOylation, and ubiquitination. These rapid and dynamic modifications may be combinatorial and interact (i.e. may be sequential, complement, or oppose each other), creating a vast array of uniquely modified receptor subspecies that allow for diverse receptor behaviors that enable highly sensitive and context-dependent hormone action. For example, in response to hormone or growth factor membrane-initiated signaling events, posttranslational modifications (PTMs) to SRs alter protein-protein interactions that govern the complex process of promoter or gene-set selection coupled to transcriptional repression or activation. Unique phosphorylation events allow SRs to associate or disassociate with specific cofactors that may include pioneer factors and other tethering partners, which specify the resulting transcriptome and ultimately change cell fate. The impact of PTMs on SR action is particularly profound in the context of breast tumorigenesis, in which frequent alterations in growth factor-initiated signaling pathways occur early and act as drivers of breast cancer progression toward endocrine resistance. In this article, with primary focus on breast cancer relevance, we review the mechanisms by which PTMs, including reversible phosphorylation events, regulate the closely related SRs, glucocorticoid receptor and progesterone receptor, allowing for precise biological responses to ever-changing hormonal stimuli.

Adipose-Derived Stem Cells for Tissue Engineering and Regenerative Medicine Applications

Adipose-derived stem cells (ASCs) are a mesenchymal stem cell source with properties of self-renewal and multipotential differentiation. Compared to bone marrow-derived stem cells (BMSCs), ASCs can be derived from more sources and are harvested more easily. Three-dimensional (3D) tissue engineering scaffolds are better able to mimic the in vivo cellular microenvironment, which benefits the localization, attachment, proliferation, and differentiation of ASCs. Therefore, tissue-engineered ASCs are recognized as an attractive substitute for tissue and organ transplantation. In this paper, we review the characteristics of ASCs, as well as the biomaterials and tissue engineering methods used to proliferate and differentiate ASCs in a 3D environment. Clinical applications of tissue-engineered ASCs are also discussed to reveal the potential and feasibility of using tissue-engineered ASCs in regenerative medicine.

The effects of anesthesia on the morphoproteomic expression of head and neck squamous cell carcinoma: a pilot study

The prognosis and disease-free survival rates for head and neck squamous cell carcinoma (HNSCC) have remained relatively stagnant for the last several decades. Moreover, as is the case with other malignancies, locoregional recurrence and distant metastasis are all too common even after seemingly successful oncologic surgery and adjuvant therapy. Recently, increased focus has been placed on understanding the influence of perioperative factors on tumor cell behavior and surgical outcomes. More specifically, emerging research suggests that anesthetic agents may play a role in cancer recurrence by interacting with prosurvival protein signaling pathways which harden tumor cells against oncologic treatments. In the present pilot study, we tested the hypothesis that inhalational anesthesia and total intravenous anesthesia (TIVA) exert differential effects on the proteomic expression of HNSCC. Ten patients with previously untreated oral cavity or oropharyngeal HNSCC were randomized to receive either sevoflurane and remifentanil or propofol and remifentanil for the duration of their respective surgeries. Morphoproteomic analysis using 10 pro-oncogenic protein markers was performed on both pre- and postanesthesia tumor samples to qualitatively grade changes in protein expression. The results of this analysis demonstrated differential expression of several protein markers. Specifically, the exposure to sevoflurane but not TIVA resulted in a statistically significant increase in the expression of cytoplasmic hypoxia-inducible factor-2alpha (P = 0.049) and nuclear p-p38 mitogenic-activated protein kinase (P = 0.041). This study represents one of the first to evaluate the effects of anesthesia on the molecular biology of HNSCC in vivo, and the results suggest that the exposure to sevoflurane may increase the expression of pro-oncogenic protein markers in HNSCC tumor cells.

P38 regulates the Wnt inhibitor Dickkopf-1 in breast cancer

Dickkopf-1 (DKK-1) is an inhibitor of canonical Wnt signalling and has been associated with the progression of osteolytic bone metastases by impairing osteoblast activity. In addition, there is growing evidence supporting a direct anti-tumour effect of DKK-1. The p38 mitogen-activated protein kinase (MAPK) regulates intracellular responses that have been linked to cell cycle, apoptosis and tumorigenesis. P38 inhibitors are currently under clinical evaluation for the treatment of malignancies. However, the influence of p38 on DKK-1 in breast cancer remains elusive. In this work, we show that p38 inhibition using SB202190 or LY2228820 potently suppressed DKK-1 expression by MDA-231 and MCF-7 breast cancer cell lines as well melanoma derived MDA-435 cells. Vice versa, activation of p38 signalling by anisomycin induced DKK-1 expression. Immunohistochemical analysis of DKK-1 expression in 97 breast cancer samples revealed that high expression of p38 was associated with a higher expression of DKK-1 compared to tumours with low p38 expression. In conclusion, these results support a role of p38 in the regulation of DKK-1 in osteolytic tumours and warrant further research on the potential of p38 inhibition for the treatment of malignant bone disease.

Butein sensitizes HeLa cells to cisplatin through the AKT and ERK/p38 MAPK pathways by targeting FoxO3a

Drug resistance remains a major challenge in cancer therapy. Butein, a polyphenolic compound, has been shown to exhibit anticancer activity through the inhibition of the activation of the protein kinase B (PKB/AKT) and mitogen-activated protein kinase (MAPK) pathways, which are two pathways known to be involved in resistance to cisplatin. Hence, we hypotheiszed that butein may be a chemosensitizer to cisplatin. In the present study, we demonstrated that butein synergistically enhanced the growth inhibitory and apoptosis-inducing effects of cisplatin on HeLa cells. Moreover, the combination of butein and cisplatin led to G1 phase arrest. We then aimed to explore the underlying mechanisms. We found that butein inhibited the activation of AKT, extracellular signal-regulated kinase (ERKs) and p38 kinases in the presence of cisplatin. The use of the AKT inhibitor, LY294002, in combination with cisplatin, induced an increase in apoptosis compared to treatment with cisplatin alone, although this effect was not as prominent as that exerted by butein in combination with cisplatin. Of note, the inhibition of ERK or p38 MAPK by U0126 or SB203580, respectively, decreased the apoptosis induced by cisplatin; however, enhanced apoptotic effects were observed with the use of ERK/p38 MAPK inhibitor in combination with butein. These data suggest that the AKT and ERK/p38 MAPK pathways are involved in the synergistic effects of butein and cisplatin. Furthermore, co-treatment with butein and cisplatin promoted the nuclear translocation and expression of forkhead box O3a (FoxO3 or FoxO3a). FoxO3a may be the key molecule on which these pathways converge and is thus implicated in the synergistic effects of butein and cisplatin. This was further confirmed by the RNAi-mediated suppression of FoxO3a. FoxO3a target genes involved in cell cycle progression and apoptosis were also investigated, and combined treatment with butein and cisplatin resulted in the downregulation of cyclin D1 and Bcl-2 and the upregulation of p27 and Bax. In addition, the combination of both agents markedly inhibited tumor growth and increased the expression of FoxO3a in mouse tumor xenograft models of cervical cancer. Taken together, to the best of our knowledge, our results reveal for the first time that butein sensitizes cervical cancer cells to cisplatin in vitro and in vivo, and these effects of butien may be related to the inhibition of the activation of the AKT and ERK/p38 MAPK pathways by targeting FoxO3a.

TGF-β1-induced EMT promotes targeted migration of breast cancer cells through the lymphatic system by the activation of CCR7/CCL21-mediated chemotaxis

Tumor cells frequently disseminate through the lymphatic system during metastatic spread of breast cancer and many other types of cancer. Yet it is not clear how tumor cells make their way into the lymphatic system and how they choose between lymphatic and blood vessels for migration. Here we report that mammary tumor cells undergoing epithelial–mesenchymal transition (EMT) in response to transforming growth factor-β (TGF-β1) become activated for targeted migration through the lymphatic system, similar to dendritic cells (DCs) during inflammation. EMT cells preferentially migrated toward lymphatic vessels compared with blood vessels, both in vivo and in 3D cultures. A mechanism of this targeted migration was traced to the capacity of TGF-β1 to promote CCR7/CCL21-mediated crosstalk between tumor cells and lymphatic endothelial cells. On one hand, TGF-β1 promoted CCR7 expression in EMT cells through p38 MAP kinase-mediated activation of the JunB transcription factor. Blockade of CCR7, or treatment with a p38 MAP kinase inhibitor, reduced lymphatic dissemination of EMT cells in syngeneic mice. On the other hand, TGF-β1 promoted CCL21 expression in lymphatic endothelial cells. CCL21 acted in a paracrine fashion to mediate chemotactic migration of EMT cells toward lymphatic endothelial cells. The results identify TGF-β1-induced EMT as a mechanism, which activates tumor cells for targeted, DC-like migration through the lymphatic system. Furthermore, it suggests that p38 MAP kinase inhibition may be a useful strategy to inhibit EMT and lymphogenic spread of tumor cells.

Glycyrrhetinic acid potently suppresses breast cancer invasion and metastasis by impairing the p38 MAPK-AP1 signaling axis

INTRODUCTION

Radix Glycyrrhiza has been used in China for thousand years to treat cancer. However, focus on its tumor-suppressing mechanism has been concentrated on its effect on tumor cell growth and apoptosis.

OBJECTIVES

With the aid of a panel of human breast cancer cell lines, we reveal that glycyrrhetinic acid (GA), a major component of Radix Glycyrrhiza, is actually a significantly more potent agent to suppress invasion than cell survival.

RESULTS

GA effectively inhibits breast cancer cell MMP-2/MMP-9 expression; GA-induced reduction in the MMP-2/9 expression is apparently mediated by GA's ability to specifically inhibit the p38 MAPK activity and its downstream AP1 activation. Moreover, we show that GA down regulates the levels of Fra-1 and c-Jun, two main components of AP1 transcription complex in invasive breast cancer cells and that AP1-specific inhibitor abrogates breast cancer cell invasion. These results suggest that GA impairs the p38 MAPK-AP1 signaling axis, leading to the repression of breast cancer cell invasion. Finally, we demonstrate that GA effectively suppresses breast tumor outgrowth and pulmonary metastasis without causing animal weight loss or eliciting liver/kidney toxicity to the recipient animals.

CONCLUSION

This study indicates that GA represents a good candidate compound for the potential development of therapeutic drug.

Roles of p38α mitogen-activated protein kinase in mouse models of inflammatory diseases and cancer

The p38α mitogen‐activated protein kinase pathway not only regulates the production of inflammatory mediators, but also controls processes related to tissue homeostasis, such as cell proliferation, differentiation and survival, which are often disrupted during malignant transformation. The versatility of this signaling pathway allows for the regulation of many specific functions depending on the cell type and context. Here, we discuss mouse models that have been used to identify in vivo functions of p38α signaling in the pathogenesis of inflammatory diseases and cancer. Experiments using genetically modified mice and pharmacological inhibitors support that targeting the p38α pathway could be therapeutically useful for some inflammatory diseases and tumor types.

Clinical significance of pAkt and pErk1/2 expression in early-stage breast cancer patients treated with anthracycline-based adjuvant chemotherapy

The expression of phosphorylated Akt (pAkt) and phosphorylated extracellular-regulated kinase 1/2 (pErk1/2) proteins may result in breast cancer progression and drug resistance in vitro, however, compelling evidence regarding the clinical significance of pAkt and pErk1/2 in early-stage breast cancer is currently lacking. Thus, the aim of the present study was to determine the prognostic value of pAkt and pErk1/2 expression in early-stage breast cancer patients treated with anthracycline-based adjuvant chemotherapy. Tumor specimens were obtained from 256 patients with early-stage breast cancer who had been treated with anthracycline-based adjuvant chemotherapy, and pAkt and pErk1/2 protein expression was immunohistochemically determined. The interactions between pAkt, pErk1/2 and clinical characteristics were assessed by performing χ² tests, and survival functions were estimated using the Kaplan-Meier method. It was identified that pAkt and pErk1/2 were expressed in 38.7 and 33.6% of patients, respectively, and that pAkt protein expression was correlated with pErk1/2 protein expression (P<0.001). In addition, after a median follow-up period of 52.5 months, the patients with pAkt- and pErk1/2-negative tumors experienced a significantly longer disease-free survival (DFS) time compared with pAkt- or pErk1/2-positive patients (P=0.028). pErk1/2 expression was associated with the decreased DFS time of the patients (P=0.049), and pAkt and pErk1/2 expression were associated with the decreased DFS time in human epidermal growth factor receptor (HER2)-positive patients (P=0.002). pErk1/2 expression was associated with chemotherapy resistance (P=0.016). Thus, the coexpression of pAkt and pErk1/2 was an independent factor for a poor prognosis in early-stage and HER2-positive breast cancer patients. By contrast, pErk1/2 expression alone may be a poor predictor for determining the efficacy of anthracycline-based chemotherapy.

JNK suppresses tumor formation via a gene-expression program mediated by ATF2

JNK and p38 phosphorylate a diverse set of substrates and, consequently, can act in a context-dependent manner to either promote or inhibit tumor growth. Elucidating the functions of specific substrates of JNK and p38 is therefore critical for our understanding of these kinases in cancer. ATF2 is a phosphorylation-dependent transcription factor and substrate of both JNK and p38. Here, we show ATF2 suppresses tumor formation in an orthotopic model of liver cancer and cellular transformation in vitro. Furthermore, we find that suppression of tumorigenesis by JNK requires ATF2. We identify a transcriptional program activated by JNK via ATF2 and provide examples of JNK- and ATF2-dependent genes that block cellular transformation. Significantly, we also show that ATF2-dependent gene expression is frequently downregulated in human cancers, indicating that amelioration of JNK-ATF2-mediated suppression may be a common event during tumor development.

P38 MAPK contributes to resistance and invasiveness of HER2- overexpressing breast cancer

Intrinsic or acquired resistance to the HER2-targeted therapy trastuzumab is a clinical concern in the treatment of patients with HER2-over-expressing metastatic breast cancers. We demonstrate here that multiple models of intrinsic and acquired resistance exhibit increased phosphorylation of p38 MAPK. Kinase inhibition of p38 rescued trastuzumab sensitivity in cells with acquired resistance. In addition, knockdown of p38 increased sensitivity to trastuzumab in an intrinsically resistant cell line. We previously reported that expression of growth differentiation factor 15 (GDF15) is increased in trastuzumab-resistant HER2-overexpressing breast cancer cells. In this study, we found that exogenous GDF15 or stable overexpression of GDF15 stimulated p38 phosphorylation in HER2-positive cells, suggesting a possible mechanism by which p38 is activated in resistant cells.GDF15 stable clones showed significantly increased invasiveness, which was rescued by p38 kinase inhibition, suggesting that p38 plays a role in the pro-invasive phenotype conferred by GDF15. Importantly, immunohistochemical analysis of a breast tumor tissue array indicated a significant (p=0.0053) correlation between HER2 and phosphorylated p38 specifically in GDF15-positive tissues. Our results suggest that p38 signaling drives trastuzumab resistance and invasiveness in HER2-overexpressing breast cancer. Upstream growth factor signals that have previously been implicated in trastuzumab resistance, such as GDF15, may contribute to the increased phosphorylation of p38 found in resistant cells.

Diet and lifestyle factors interact with MAPK genes to influence survival: the Breast Cancer Health Disparities Study

INTRODUCTION

MAPK genes are activated by a variety of factors related to growth factors, hormones, and environmental stress.

METHODS

We evaluated associations between 13 MAPK genes and survival among 1,187 nonHispanic White and 1,155 Hispanic/Native American (NA) women diagnosed with breast cancer. We assessed the influence of diet, lifestyle, and genetic ancestry on these associations. Percent NA ancestry was determined from 104 Ancestry Informative Markers. Adaptive rank truncation product (ARTP) was used to determine gene and pathway significance.

RESULTS

Associations were predominantly observed among women with lower NA ancestry. Specifically, the mitogen-activated protein kinases (MAPK) pathway was associated with all-cause mortality (P ARTP = 0.02), but not with breast cancer-specific mortality (P ARTP = 0.10). However, MAP2K1 and MAP3K9 were associated with both breast cancer-specific and all-cause mortality. MAPK12 (P ARTP = 0.05) was only associated with breast cancer-specific mortality, and MAP3K1 (P ARTP = 0.02) and MAPK1 (P ARTP = 0.05) were only associated with all-cause mortality. Among women with higher NA ancestry, MAP3K2 was significantly associated with all-cause mortality (P ARTP = 0.04). Several diet and lifestyle factors, including alcohol consumption, caloric intake, dietary folate, and cigarette smoking, significantly modified the associations with MAPK genes and all-cause mortality.

CONCLUSIONS

Our study supports an association between MAPK genes and survival after diagnosis with breast cancer, especially among women with low NA ancestry. The interaction between genetic variation in the MAPK pathway with diet and lifestyle factors for all women supports the important role of these factors for breast cancer survivorship.

p38α MAPK pathway: A key factor in colorectal cancer therapy and chemoresistance

Colorectal cancer (CRC) remains one of the most common malignancies in the world. Although surgical resection combined with adjuvant therapy is effective at the early stages of the disease, resistance to conventional therapies is frequently observed in advanced stages, where treatments become ineffective. Resistance to cisplatin, irinotecan and 5-fluorouracil chemotherapy has been shown to involve mitogen-activated protein kinase (MAPK) signaling and recent studies identified p38α MAPK as a mediator of resistance to various agents in CRC patients. Studies published in the last decade showed a dual role for the p38α pathway in mammals. Its role as a negative regulator of proliferation has been reported in both normal (including cardiomyocytes, hepatocytes, fibroblasts, hematopoietic and lung cells) and cancer cells (colon, prostate, breast, lung tumor cells). This function is mediated by the negative regulation of cell cycle progression and the transduction of some apoptotic stimuli. However, despite its anti-proliferative and tumor suppressor activity in some tissues, the p38α pathway may also acquire an oncogenic role involving cancer related-processes such as cell metabolism, invasion, inflammation and angiogenesis. In this review, we summarize current knowledge about the predominant role of the p38α MAPK pathway in CRC development and chemoresistance. In our view, this might help establish the therapeutic potential of the targeted manipulation of this pathway in clinical settings.

Phosphorylated p38, a negative prognostic biomarker, complements TNM staging prognostication in colorectal cancer

Phosphorylated p38 (p-p38) played a pivotal role in the regulation of disease progression and correlated with tumor prognosis. Here, we characterized the prognostic effect of p-p38 in colorectal cancer (CRC). Three hundred and sixteen CRC patients in stages I-III were recruited in this study. P-p38 expression was semi-quantitatively evaluated using tissue microarrays and immunohistochemistry staining. Overall survival (OS), disease-free survival (DFS), local failure-free survival (LFFS), and distant metastasis-free survival (DMFS) of patient subgroups, segregated by p-p38 expression level and clinical stage, were compared using Kaplan-Meier analysis. We found that p-p38 was overexpressed in 48.1 % (152/316) CRC tissues, whereas low or deficiently expressed in normal adjacent epithelia. Overexpression of p-p38 predicted poor OS (P < 0.001), DFS (P = 0.002), LFFS (P = 0.016), and DMFS (P = 0.025) in CRC. Importantly, patient subgroups in the early stage (stages I + II) and with low p-p38 had similar OS, PFS, LFFS, and DMFS probabilities to that of stage I, whereas those with high p-p38 were similar to stage III disease. In addition, for stage III disease, the subgroup with low p-p38 had a similar survival probability to that of stage I, whereas the subgroup with high p-p38 had the worst survival. Multivariate Cox analysis confirmed that p-p38 was indeed a significantly independent factor for death, recurrence, and distant metastases in CRC. Our results demonstrated that p-p38 was a negative independent prognostic factor for CRC. Complementing TNM staging with p-p38 might refine the risk definition more accurately for a subset of patients.

Role of p38 MAP Kinase Signal Transduction in Solid Tumors

Mitogen-activated protein kinases (MAPKs) mediate a wide variety of cellular behaviors in response to extracellular stimuli. One of the main subgroups, the p38 MAP kinases, has been implicated in a wide range of complex biologic processes, such as cell proliferation, cell differentiation, cell death, cell migration, and invasion. Dysregulation of p38 MAPK levels in patients are associated with advanced stages and short survival in cancer patients (e.g., prostate, breast, bladder, liver, and lung cancer). p38 MAPK plays a dual role as a regulator of cell death, and it can either mediate cell survival or cell death depending not only on the type of stimulus but also in a cell type specific manner. In addition to modulating cell survival, an essential role of p38 MAPK in modulation of cell migration and invasion offers a distinct opportunity to target this pathway with respect to tumor metastasis. The specific function of p38 MAPK appears to depend not only on the cell type but also on the stimuli and/or the isoform that is activated. p38 MAPK signaling pathway is activated in response to diverse stimuli and mediates its function by components downstream of p38. Extrapolation of the knowledge gained from laboratory findings is essential to address the clinical significance of p38 MAPK signaling pathways. The goal of this review is to provide an overview on recent progress made in defining the functions of p38 MAPK pathways with respect to solid tumor biology and generate testable hypothesis with respect to the role of p38 MAPK as an attractive target for intervention of solid tumors.

Characterization of antiproliferative activity constituents from Artocarpus heterophyllus

Artocarpus heterophyllus is an evergreen fruit tree cultivated in many tropical regions. Previous studies have shown that some of its compositions exhibited potential tyrosinase inhibition activities. This study indentified 8 new phenolic compounds, artoheterophyllins E-J (1-6), 4-geranyl-2',3,4',5-tetrahydroxy-cis-stilbene (7), and 5-methoxymorican M (8) and 2 new natural compounds (9 and 10), 2,3-dihydro-5,7-dihydroxy-2-(2-hydroxy-4-methoxyphenyl)-4H-benzopyran-4-one and 6-[(1S,2S)-1,2-dihydroxy-3-methylbutyl]-2-(2,4-dihydroxyphenyl)-5-hydroxy-7-methoxy-3-(3-methyl-2-buten-1-yl)-4H-1-benzopyran-4-one, together with 23 known compounds (11-33), from the ethanol extract of the wood of A. heterophyllus. The structures of the eight new compounds (1-8) and two new natural compounds were established by extensive 1D- and 2D-NMR experiments. The anticancer effects of the isolated compounds were examined in MCF-7, H460, and SMMC-7721 human cancer cell lines by MTT assay. Compounds 5, 11, 12, and 30 significantly reduced the cell viabilities of these cell lines. Especially, compounds 11 and 30 resulted in more potent cytotoxicity than the positive control, 5-fluorouracil (5-Fu), in SMMC-7721 cell line, with IC50 values of 15.85 and 12.06 μM, whereas compound 30 exhibited more potent cytotoxicity than 5-Fu in NCI-H460 cell line, with an IC50 value of 5.19 μM. In addition, this study suggests that compounds 11 and 30 from the wood of A. heterophyllus have anticancer potential via MAPK pathways.

The mitogen-activated protein (MAP) kinases p38 and extracellular signal-regulated kinase (ERK) are involved in hepatocyte-mediated phenotypic switching in prostate cancer cells

The greatest challenge for the seeding of cancer in metastatic sites is integration into the ectopic microenvironment despite the lack of an orthotopic supportive environment and presence of pro-death signals concomitant with a localized "foreign-body" inflammatory response. In this metastatic location, many carcinoma cells display a reversion of the epithelial-to-mesenchymal transition that marks dissemination in the primary tumor mass. This mesenchymal to epithelial reverting transition (MErT) is thought to help seeding and colonization by protecting against cell death. We have previously shown that hepatocyte coculture induces the re-expression of E-cadherin via abrogation of autocrine EGFR signaling pathway in prostate cancer (PCa) cells and that this confers a survival advantage. Herein, we show that hepatocytes educate PCa to undergo MErT by modulating the activity of p38 and ERK1/2. Hepatocytes inhibited p38 and ERK1/2 activity in prostate cancer cells, which allowed E-cadherin re-expression. Introduction of constitutively active MEK6 and MEK1 to DU145 cells cocultured with hepatocytes abrogated E-cadherin re-expression. At least a partial phenotypic reversion can be achieved by suppression of p38 and ERK1/2 activation in DU145 cells even in the absence of hepatocytes. Interestingly, these mitogen-activated protein kinase activities were also triggered by re-expressed E-cadherin leading to p38 and ERK1/2 activity in PCa cells; these signals provide protection to PCa cells upon challenge with chemotherapy and cell death-inducing cytokines. We propose that distinct p38/ERK pathways are related to E-cadherin levels and function downstream of E-cadherin allowing, respectively, for hepatocyte-mediated MErT and tumor cell survival in the face of death signals.

Characterization of LY2228820 dimesylate, a potent and selective inhibitor of p38 MAPK with antitumor activity

p38α mitogen-activated protein kinase (MAPK) is activated in cancer cells in response to environmental factors, oncogenic stress, radiation, and chemotherapy. p38α MAPK phosphorylates a number of substrates, including MAPKAP-K2 (MK2), and regulates the production of cytokines in the tumor microenvironment, such as TNF-α, interleukin-1β (IL-1β), IL-6, and CXCL8 (IL-8). p38α MAPK is highly expressed in human cancers and may play a role in tumor growth, invasion, metastasis, and drug resistance. LY2228820 dimesylate (hereafter LY2228820), a trisubstituted imidazole derivative, is a potent and selective, ATP-competitive inhibitor of the α- and β-isoforms of p38 MAPK in vitro (IC(50) = 5.3 and 3.2 nmol/L, respectively). In cell-based assays, LY2228820 potently and selectively inhibited phosphorylation of MK2 (Thr334) in anisomycin-stimulated HeLa cells (at 9.8 nmol/L by Western blot analysis) and anisomycin-induced mouse RAW264.7 macrophages (IC(50) = 35.3 nmol/L) with no changes in phosphorylation of p38α MAPK, JNK, ERK1/2, c-Jun, ATF2, or c-Myc ≤ 10 μmol/L. LY2228820 also reduced TNF-α secretion by lipopolysaccharide/IFN-γ-stimulated macrophages (IC(50) = 6.3 nmol/L). In mice transplanted with B16-F10 melanoma, tumor phospho-MK2 (p-MK2) was inhibited by LY2228820 in a dose-dependent manner [threshold effective dose (TED)(70) = 11.2 mg/kg]. Significant target inhibition (>40% reduction in p-MK2) was maintained for 4 to 8 hours following a single 10 mg/kg oral dose. LY2228820 produced significant tumor growth delay in multiple in vivo cancer models (melanoma, non-small cell lung cancer, ovarian, glioma, myeloma, breast). In summary, LY2228820 is a p38 MAPK inhibitor, which has been optimized for potency, selectivity, drug-like properties (such as oral bioavailability), and efficacy in animal models of human cancer.

Inhibition of p38 MAPK sensitizes tumour cells to cisplatin-induced apoptosis mediated by reactive oxygen species and JNK

The p38 MAPK pathway is an important regulator of many cellular responses. It is well established that p38 MAPK signalling negatively regulates epithelial cell transformation, but enhanced p38 MAPK activity has been also correlated with bad clinical prognosis in some tumour types. Here, we provide genetic and pharmacological evidence showing that p38 MAPK inhibition cooperates with the chemotherapeutic agent cisplatin to kill tumour cells. We show that p38 MAPK inhibition results in ROS upregulation, which in turn activates the JNK pathway via inactivation of phosphatases, sensitizing human tumour cells to cisplatin-induced apoptosis. Using a mouse model for breast cancer, we confirm that inhibition of p38 MAPK cooperates with cisplatin treatment to reduce tumour size and malignancy in vivo. Taken together, our results illustrate a new function of p38 MAPK that helps tumour cells to survive chemotherapeutic drug treatments, and reveal that the combination of p38 MAPK inhibitors with cisplatin can be potentially exploited for cancer therapy.

Expression and activation of P38 MAP kinase in invasive ductal breast cancers: correlation with expression of the estrogen receptor, HER2 and downstream signaling phosphorylated proteins

MAP kinase signaling proteins have major implications in the molecular oncogenesis of breast cancers and have been extensively investigated as putative targets for therapy. This study reports the investigation of the expression of P38 MAPK and its phosphorylated form (p-P38 MAPK) in clinical specimens of invasive breast carcinomas and their correlation with estrogen receptor (ER) and HER2 expression, as well as MAPK and PI3 kinase-AKT pathway signaling phosphorylated proteins. Expression levels of P38 MAPK and p-P38 MAPK as well as p-AKT, p-GSK3β, p-S6 kinase, p-MEK1 and p-ERK1/2 were quantitatively assessed using multiplex bead immunoassay in frozen specimens from 45 invasive ductal breast cancers. Twenty-nine specimens were ER+, 15 were HER2+ and 10 were triple‑negative breast cancers (TNBCs). P38 MAPK was found to be expressed in all tumor specimens and was significantly (P=0.002) overexpressed in ER+ tumors. P38 MAPK expression was lower in TNBCs than in all of the other tumors. The median expression of p-P38 MAPK was also higher in ER+ tumors while lower in the TNBCs. HER2 status had no effect on P38 MAPK and p-P38 MAPK expression. No variation in the phosphorylation rate of P38 MAPK was observed in relation with ER, HER2 or TNBC status. Significantly higher (P=0.0048) expression of p-AKT was observed in HER2+ tumors. No significant difference in p-MEK1, p-GSK3β and p-S6K expression was found in any other comparisons based on ER and HER2 expression subtypes. Investigation of the expression of multiple phosphorylated signaling proteins can be used for personalized targeted therapy. In invasive breast cancer, the overexpression of P38 MAPK may serve as a biomarker for the evaluation of P38 MAPK inhibitors.

Inhibitory Effects of PC-SPESII Herbal Extract on Human Breast Cancer Metastasis

Cancer metastasis is refractory to most forms of chemotherapy. Conventional and alternative drugs, such as Chinese herbal remedies, have been developed to target metastatic cancer cells. In this study, we investigated the effects of PC-SPESII, an herbal formulation, on the migration, invasion, and metastasis of an experimental human breast cancer cell line in vivo and in vitro. PC-SPESII suppressed pulmonary metastasis and tumor growth of MDA-MB-231 human breast cancer xenografts without affecting body weight, liver function, and kidney function. PC-SPESII also inhibited MDA-MB-231 cell migration and invasion in vitro in a dose-dependent manner. Based on ELISA analysis, secretion of MMP-2 and MMP-9, proteins associated with extracellular matrix degradation, was reduced in response to PC-SPESII treatment. Western blot analysis of whole-cell extracts revealed that the levels of proteolytic proteins associated with matrix and base membrane degradation (MMP-2, MMP-9, and uPA) were decreased and the levels of their endogenous inhibitors (TIMP1 and TIMP2) were increased. Moreover, the p38MAPK and SAPK/JNK signaling pathway, which stimulates proteolytic enzymes and matrix degradation, was inhibited by PC-PSESII. Remarkably, cotreatment with PC-PSESII and p38MAPK or SAPK/JNK inhibitors magnified the antimetastatic phenotype. Our results indicate that PC-PSESII impairs human breast cancer metastasis by regulating proteolytic enzymes and matrix dynamics through the p38MAPK and SAPK/JNK pathway.

Vandetanib combined with a p38 MAPK inhibitor synergistically reduces glioblastoma cell survival

The survival for patients with high-grade glioma is poor, and only a limited number of patients respond to the therapy. The aim of this study was to analyze the significance of using p38 MAPK phosphorylation as a prognostic marker in high-grade glioma patients and as a therapeutic target in combination chemotherapy with vandetanib. p38 MAPK phosphorylation was analyzed with immunohistochemistry in 90 high-grade glioma patients. Correlation between p38 MAPK phosphorylation and overall survival was analyzed with Mann-Whitney U test analysis. The effects on survival of glioblastoma cells of combining vandetanib with the p38 MAPK inhibitor SB 203580 were analyzed in vitro with the median-effect method with the fluorometric microculture cytotoxicity assay. Two patients had phosphorylated p38 MAPK in both the cytoplasm and nucleus, and these two presented with worse survival than patients with no detectable p38 MAPK phosphorylation or phosphorylated p38 MAPK only in the nucleus. This was true for both high-grade glioma patients (WHO grade III and IV, n = 90, difference in median survival: 6.1 months, 95 % CI [0.20, 23], p = 0.039) and for the subgroup with glioblastoma patients (WHO grade IV, n = 70, difference in median survival: 6.1 months, 95 % CI [0.066, 23], p = 0.043). The combination of vandetanib and the p38 MAPK inhibitor SB 203580 had synergistic effects on cell survival for glioblastoma-derived cells in vitro. In conclusion, p38 MAPK phosphorylation may be a prognostic marker for high-grade glioma patients, and vandetanib combined with a p38 MAPK inhibitor may be useful combination chemotherapy for glioma patients.