Mitogen-Activated Protein Kinase Signaling Pathway in Cutaneous Melanoma: An Updated Review

Biological and metabolomics-guided isolation of tetrahydrofurofuran lignan from Croton spp. with antiproliferative activity against human melanoma cell line

The Croton genus (Euphorbiaceae) is recognized as a promising source for identifying bioactive compounds with antiproliferative activity. However, knowledge on the chemical composition and activity of Croton floribundus, Croton echinocarpus, and Croton zehntneri is limited. Thus, this study aimed to investigate the antiproliferative activity of these species on cells derived from tumoral breast, lung, and melanoma cells, and primary fibroblasts derived from human skin. Metabolomic strategies were applied via ultra-performance liquid chromatography coupled with high-resolution mass spectrometry and multivariate statistical analysis to target the main active compound. The C. floribundus leaf extract exhibited the highest activity, with an IC50 value lower than that of the reference drug - temozolomide - in the most responsive cell line - SK-MEL-147 - and in all the evaluated melanoma cell lines (SK-MEL-147, CHL-1 and WM-1366). Four tetrahydrofurofuran lignans were isolated for the first time from the most promising fraction of the C. floribundus extract. According to the metabolomic and multivariate statistical analyses, the isolated lignan epi-yangambin constituted the main antiproliferative compound against SK-MEL-147; furthermore, it exhibited selective antiproliferative activity for this cell line (IC50 = 13.09 μg/mL and selectivity index = 3.82; temozolomide, IC50 = 121.50 μg/mL) due to, at least in part, its ability to inhibit cell cycle progression at G2/M. This is especially relevant considering the high resistance of melanoma cells to available drugs. Thus, epi-yangambin can serve as a prototype for further antiproliferative investigations.

Oxidative Stress and Redox-Dependent Signaling in Prostate Cancer

Tumor emergence and progression is complicated by the dual role of reactive oxygen species (ROS). Low concentrations of ROS are essential for many intracellular metabolic processes and cell proliferation, while excessive ROS generation disrupts the mechanisms of cancer suppression, leading to the cell damage and death. A long-term imbalance in the ROS/antioxidant ratio and upregulation of the ROS generation due to the reduced efficacy of the antioxidant defense system cause chronic oxidative stress resulting in the damage of proteins, lipid, and DNA molecules and cancer development. Numerous data demonstrate that prostate cancer (the most common cancer in males) is associated with the development of oxidative stress. However, the reasons for the emergence of prostate cancer, as well as changes in the redox signaling and cellular redox homeostasis in this disease, are still poorly understood. The review examines the role of prooxidant and antioxidant enzyme systems, the imbalance in their activity leading to the oxidative stress development, changes in the key components of redox signaling, and the role of microRNAs in the modulation of redox status of cancer cells in prostate cancer.

Impact of the Protein Data Bank on antineoplastic approvals

Open access to 3D structure information from the Protein Data Bank (PDB) facilitated discovery and development of >90% of the 79 new antineoplastic agents (54 small molecules, 25 biologics) with known molecular targets approved by the FDA 2010-2018. Analyses of PDB holdings, the scientific literature and related documents for each drug-target combination revealed that the impact of public-domain 3D structure data was broad and substantial, ranging from understanding target biology (∼95% of all targets) to identifying a given target as probably druggable (∼95% of all targets) to structure-guided lead optimization (>70% of all small-molecule drugs). In addition to aggregate impact assessments, illustrative case studies are presented for three protein kinase inhibitors, an allosteric enzyme inhibitor and seven advanced-stage melanoma therapeutics.

Non-Thermal Atmospheric Pressure Bio-Compatible Plasma Stimulates Apoptosis via p38/MAPK Mechanism in U87 Malignant Glioblastoma

Nonthermal plasma is a promising novel therapy for the alteration of biological and clinical functions of cells and tissues, including apoptosis and inhibition of tumor progression. This therapy generates reactive oxygen and nitrogen species (RONS), which play a major role in anticancer effects. Previous research has verified that plasma jets can selectively induce apoptosis in various cancer cells, suggesting that it could be a potentially effective novel therapy in combination with or as an alternative to conventional therapeutic methods. In this study, we determined the effects of nonthermal air soft plasma jets on a U87 MG brain cancer cell line, including the dose- and time-dependent effects and the physicochemical and biological correlation between the RONS cascade and p38/mitogen-activated protein kinase (MAPK) signaling pathway, which contribute to apoptosis. The results indicated that soft plasma jets efficiently inhibit cell proliferation and induce apoptosis in U87 MG cells but have minimal effects on astrocytes. These findings revealed that soft plasma jets produce a potent cytotoxic effect via the initiation of cell cycle arrest and apoptosis. The production of reactive oxygen species (ROS) in cells was tested, and an intracellular ROS scavenger, N-acetyl cysteine (NAC), was examined. Our results suggested that soft plasma jets could potentially be used as an effective approach for anticancer therapy.

Construction and Validation of a Protein Prognostic Model for Lung Squamous Cell Carcinoma

Lung squamous cell carcinoma (LUSCC), as the major type of lung cancer, has high morbidity and mortality rates. The prognostic markers for LUSCC are much fewer than lung adenocarcinoma. Besides, protein biomarkers have advantages of economy, accuracy and stability. The aim of this study was to construct a protein prognostic model for LUSCC. The protein expression data of LUSCC were downloaded from The Cancer Protein Atlas (TCPA) database. Clinical data of LUSCC patients were downloaded from The Cancer Genome Atlas (TCGA) database. A total of 237 proteins were identified from 325 cases of LUSCC patients based on the TCPA and TCGA database. According to Kaplan-Meier survival analysis, univariate and multivariate Cox analysis, a prognostic prediction model was established which was consisted of 6 proteins (CHK1_pS345, CHK2, IRS1, PAXILLIN, BRCA2 and BRAF_pS445). After calculating the risk values of each patient according to the coefficient of each protein in the risk model, the LUSCC patients were divided into high risk group and low risk group. The survival analysis demonstrated that there was significant difference between these two groups (p= 4.877e-05). The area under the curve (AUC) value of the receiver operating characteristic (ROC) curve was 0.699, which suggesting that the prognostic risk model could effectively predict the survival of LUSCC patients. Univariate and multivariate analysis indicated that this prognostic model could be used as independent prognosis factors for LUSCC patients. Proteins co-expression analysis showed that there were 21 proteins co-expressed with the proteins in the risk model. In conclusion, our study constructed a protein prognostic model, which could effectively predict the prognosis of LUSCC patients.

Targeting BRAF mutations in non-small cell lung cancer

The management of non-small cell lung cancer (NSCLC) has changed significantly with the discovery of specific drug targets. These drugs have helped transform patient care and outcomes. BRAF mutated NSCLC is now recognised as a rare form of lung cancer. Data has begun to emerge supporting the use of BRAF/MEK inhibitors that target BRAF^V600E mutations in the mitogen-activated protein kinase (MAPK) pathway. Multiple phase 2 studies have been performed assessing the effectiveness of single agent BRAF inhibition and combination BRAF/MEK inhibition in pretreated and untreated patient populations. Consistently overall response rate (ORR) and progression free survival (PFS) are improved with the addition of a MEK inhibitor. A 2-cohort phase 2 study demonstrated an ORR of 33% vs. 67% and PFS of 5.5 vs. 10.2 months in those treated with single agent dabrafenib vs. dabrafenib and trametinib respectively. A similar ORR of 63% and PFS of 10.9 months was seen in a separate phase 2 study in patients treated with Dabrafenib and Trametinib in the first line setting. Immunotherapy is beginning to show promise as an active therapy in BRAF mutated NSCLC in both V600E and non-V600E subtypes; however, this requires further study and clarification. BRAF^V600E mutated NSCLC treated with chemotherapy have been widely reported to be associated with worse outcomes when compared to those without a mutation. With efficacy of combination BRAF/MEK established and early evidence of immune checkpoint inhibitor activity careful consideration should be given when choosing the most appropriate therapy in this select patient cohort.

Mechanism of miR-143-3p inhibiting proliferation, migration and invasion of osteosarcoma cells by targeting MAPK7

Objective: To investigate the effects of miR-143-3p and MAPK7 on the proliferation, migration, and invasion of U2OS human osteosarcoma (OS) cells. Methods: The expression of miR-143-3p and MAPK7 in U2OS cells were detected by qRT-PCR, and the protein level of MAPK7 was measured by western blot assay. The targeting relationship between miR-143-3p and MAPK7 was predicted by TargetScan and verified by dual luciferase reporter assay. MTT and Transwell assays were used to detect cell viability, migrated cells and invaded cells of U2OS cells. Results: Compared with hFOB1.19 cells, the expression of miR-143-3p was down-regulated and MAPK7 was up-regulated in U2OS cells. Cell viability, migration and invasion ability significantly decreased induced by miR-143-3p overexpression or MAPK7 knockdown in U2OS cells. The results of dual luciferase reporter assay indicated that miR-143-3p interacted with MAPK7. Furthermore, overexpression of MAPK7 could reverse the inhibitory effects on cell proliferation, migration and invasion in U2OS cells induced by miR-143-3p mimics. Conclusion: miR-143-3p could inhibit proliferation, migration and invasion of U2OS cells by targeting MAPK7.

Molecular Pathways in Melanomagenesis: What We Learned from Next-Generation Sequencing Approaches

PURPOSE OF REVIEW

Conventional clinico-pathological features in melanoma patients should be integrated with new molecular diagnostic, predictive, and prognostic factors coming from the expanding genomic profiles. Cutaneous melanoma (CM), even differing in biological behavior according to sun-exposure levels on the skin areas where it arises, is molecularly heterogeneous. The next-generation sequencing (NGS) approaches are providing data on mutation landscapes in driver genes that may account for distinct pathogenetic mechanisms and pathways. The purpose was to group and classify all somatic driver mutations observed in the main NGS-based studies.

RECENT FINDINGS

Whole exome and whole genome sequencing approaches have provided data on spectrum and distribution of genetic and genomic alterations as well as allowed to discover new cancer genes underlying CM pathogenesis. After evaluating the mutational status in a cohort of 686 CM cases from the most representative NGS studies, three molecular CM subtypes were proposed: BRAFmut, RASmut, and non-BRAFmut/non-RASmut.

Prenatal exposure to perfluorooctanoic acid induces nerve growth factor expression in cerebral cortex cells of mouse offspring

Previous studies have showed perfluorooctanoic acid (PFOA) inducing cytotoxicity in an organ. In addition, epidemiological data show that high level of PFOA in cord blood of a pregnant woman is detected. Therefore, we extrapolate that circulating PFOA may affect organogenesis in offspring, such as the brain. In this study, intrauterine exposure to PFOA in mice was used to characterize the potential impacts of prenatal PFOA exposure on cerebral cortex cells of postnatal 21 (PND21) offspring. In an ex vivo cell model, PND21-based cortex cells were exposed to PFOA or/and nerve growth factor (NGF)-specific inhibitor before further biochemical assays. As results, biochemical data showed increased trends of liver metabolic enzymes in sera of PFOA-treated PND21 mice. Interestingly, PFOA-treated PND21 mice resulted in increased levels of NGF in sera and cortex cells. In addition, PFOA-exposed cerebral cortex cells induced NGF and proliferating cell nuclear antigen (PCNA) expressions, while exposure to PFOA/NGF-specific inhibitor downregulated expressions of NGF and PCNA. In addition, Nissl-labeled, NGF-positive cells, and NGF protein expression in cortex cells of PFOA-treated PND21 mice were upregulated, respectively. Further, immunoblotting assays showed that intracephalic poly (ADP-ribose) polymerase (PARP) and p42/44 mitogen-activated protein kinase (MAPK) proliferation-regulated protein levels were elevated in PFOA-treated cortex cells. Taken together, our current findings indicate that the prenatal PFOA exposure may induce proliferation of cerebral cortex cells in PND21 mice through promoting intracephalic NGF expression in the cortex.

JMJD6 promotes melanoma carcinogenesis through regulation of the alternative splicing of PAK1, a key MAPK signaling component

Background

Melanoma, originated from melanocytes located on the basal membrane of the epithelial tissue, is the most aggressive form of skin cancer that accounts for 75% of skin cancer-related death. Although it is believed that BRAF mutation and the mitogen-activated protein kinase (MAPK) pathway play critical roles in the pathogenesis of melanoma, how the MAPK signaling is regulated in melanoma carcinogenesis is still not fully understood.

Methods

We characterized JMJD6 expression in melanoma tissue array by immunohistochemistry analysis. We used human melanoma A375, 451Lu and SK-MEL-1 cell lines for in vitro proliferation and invasion experiments, and xenograft transplanted mice using murine melanoma B16F10 cells by bioluminescence imaging for in vivo tumor growth and pulmonary metastasis assessments. Endothelial tube formation assay, chicken yolk sac membrane assay and matrigel plug assay were performed to test the effect of JMJD6 on the angiogenic potential in vitro and in vivo.

Results

Here we report that the jumonji C domain-containing demethylase/hydroxylase JMJD6 is markedly up-regulated in melanoma. We found that high expression of JMJD6 is closely correlated with advanced clinicopathologic stage, aggressiveness, and poor prognosis of melanoma. RNA-seq showed that knockdown of JMJD6 affects the alternative splicing of a panel of transcripts including that encoding for PAK1, a key component in MAPK signaling pathway. We demonstrated that JMJD6 enhances the MAPK signaling and promotes multiple cellular processes including melanogenesis, proliferation, invasion, and angiogenesis in melanoma cells. Interestingly, JMJD6 is transcriptionally activated by c-Jun, generating a feedforward loop to drive the development and progression of melanoma.

Conclusions

Our results indicate that JMJD6 is critically involved in melanoma carcinogenesis, supporting the pursuit of JMJD6 as a potential biomarker for melanoma aggressiveness and a target for melanoma intervention.

Electronic supplementary material

The online version of this article (10.1186/s12943-017-0744-2) contains supplementary material, which is available to authorized users.

Urban particulate matter triggers lung inflammation via the ROS-MAPK-NF-κB signaling pathway

Background

Particulate matter (PM) is a high risk factor for various respiratory diseases and triggers an inflammatory response in lung tissues. However, the molecular mechanism of the PM-induced inflammatory response is incompletely understood.

Methods

Human bronchial epithelial cells (HBECs) were treated with the urban PM 1649b for assessment of the inflammatory response. The intracellular level of reactive oxygen species (ROS) was measured by flow cytometry. PM-activated signaling pathways were addressed with specific inhibitors. In vivo, the C57 mice model of PM-induced acute lung inflammation was established with intratracheal instillation of PM for 2 consecutive days. The oxidant stress in lung tissues was assessed with dihydroethidium (DHE) staining, and malondialdehyde (MDA) activity and hydrogen peroxide (H₂O₂) assays. The histopathologic changes in lung tissues and number of inflammatory cells in bronchoalveolar lavage fluid (BALF) were examined. Expression of pro-inflammatory cytokines in BALF was measured by ELISA.

Results

PM increased the expression of interleukin (IL)-1β, IL-6, IL-8, matrix metalloproteinase (MMP)-9 and cyclooxygenase (COX)-2 in a dose-dependent manner. ROS generation and activation of MAPK (ERK, JNK, p38 MAPK) and NF-κB pathways were detected in PM-exposed HBECs. Pretreatment with N-acetylcysteine (NAC) led to the inflammatory response, ROS level and activation of the MAPK and NF-κB pathways to be attenuated. Blockade of ERK, JNK or p38 MAPK pathway with specific inhibitor prevented the release of pro-inflammatory cytokines and activation of the NF-κB pathway. Inhibition of the NF-κB pathway reduced the expression of pro-inflammatory cytokines. In vivo, PM exposure increased oxidant stress in lung tissues, infiltration of inflammatory cells around PM in lung tissues, the number of total cells and inflammatory cells in BALF, and the concentrations of IL-1β, IL-6, IL-8 and MMP-9 in BALF, all of which were reversed partially upon NAC treatment.

Conclusions

PM exposure enhanced the airway inflammatory response significantly through ROS-mediated activation of MAPK (ERK, JNK, p38 MAPK) and downstream NF-κB signaling pathways. Oxidative stress appeared to be the key regulator for PM-induced lung inflammation. These results suggested the molecular mechanism of lung inflammation caused by PM.