Rottlerin induces apoptosis of HT29 colon carcinoma cells through NAG-1 upregulation via an ERK and p38 MAPK-dependent and PKC δ-independent mechanism

Growth differentiation factor-15 overexpression promotes cell proliferation and predicts poor prognosis in cerebral lower-grade gliomas correlated with hypoxia and glycolysis signature

AIMS

Growth differentiation factor-15 (GDF15) plays complex and controversial roles in cancer. In this study, the prognostic value and the exact biological function of GDF15 in cerebral lower-grade gliomas (LGGs) and its potential molecular targets were examined.

MAIN METHODS

Wilcoxon signed-rank test and logistic regression were applied to analyze associations between GDF15 expression and clinical characteristics using the Cancer Genome Atlas (TCGA) database. Overall survival was analyzed using Kaplan-Meier and Cox analyses. Gene set enrichment analysis (GSEA) and the hypoxia risk model was conducted to identify the potential molecular mechanisms underlying the effects of GDF15 on LGGs tumorigenesis. The biological function of GDF15 was examined using gain- and loss-of-function experiments, and a recombinant hGDF15 protein in LGG SW1783 cells in vitro.

KEY FINDINGS

We found that higher GDF15 expression is associated with poor clinical features in LGG patients, and an independent risk factor for overall survival among LGG patients. GSEA results showed that the poor prognostic role of GDF15 in LGGs is related to hypoxia and glycolysis signatures, which was further validated using the hypoxia risk model. Furthermore, GDF15 overexpression facilitated cell proliferation, while GDF15 siRNA inhibits cell proliferation in LGG SW1783 cells. In addition, GDF15 was upregulated upon CoCl2 treatment which induces hypoxia, correlating with the upregulation of the expressions of HIF-1α and glycolysis-related key genes in SW1783 cells.

SIGNIFICANCE

GDF15 may promote LGG tumorigenesis that is associated with the hypoxia and glycolysis pathways, and thus could serve as a promising molecular target for LGG prevention and therapy.

Preclinical Drug Discovery in Colorectal Cancer: A Focus on Natural Compounds

BACKGROUND

Colorectal cancer (CRC) is considered one of the most predominant and deadly cancer globally. Nowadays, the main clinical management for this cancer includes chemotherapy and surgery; however, these treatments result in the occurrence of drug resistance and severe side effects, and thus it is a crucial requirement to discover an alternative and potential therapy for CRC treatment. Numerous therapeutic cancers were initially recognized from natural metabolites utilized in traditional medicine, and several recent types of research have shown that many natural products own potential effects against CRC and may assist the action of chemotherapy for the treatment of CRC. It has been indicated that most patients are well tolerated by natural compounds without showing any toxicity signs even at high doses. Conventional chemotherapeutics interaction with natural medicinal compounds presents a new feature in cancer exploration and treatment. Most of the natural compounds overwhelm malignant cell propagation by apoptosis initiation of CRC cells and arresting of the cell cycle (especially at G, S, and G2/M phase) that result in inhibition of tumor growth.

OBJECTIVE

This mini-review aimed to focus on natural compounds (alkaloids, flavonoids, polysaccharides, polyphenols, terpenoids, lactones, quinones, etc.) that were identified to have anti- CRC activity in vitro on CRC cell lines and/or in vivo experiments on animal models.

CONCLUSION

Most of the studied active natural compounds possess anti-CRC activity via different mechanisms and pathways in vitro and in vivo that might be used as assistance by clinicians to support chemotherapy therapeutic strategy and treatment doses for cancer patients.

Progress in the Development of Eukaryotic Elongation Factor 2 Kinase (eEF2K) Natural Product and Synthetic Small Molecule Inhibitors for Cancer Chemotherapy

Eukaryotic elongation factor 2 kinase (eEF2K or Ca2+/calmodulin-dependent protein kinase, CAMKIII) is a new member of an atypical α-kinase family different from conventional protein kinases that is now considered as a potential target for the treatment of cancer. This protein regulates the phosphorylation of eukaryotic elongation factor 2 (eEF2) to restrain activity and inhibit the elongation stage of protein synthesis. Mounting evidence shows that eEF2K regulates the cell cycle, autophagy, apoptosis, angiogenesis, invasion, and metastasis in several types of cancers. The expression of eEF2K promotes survival of cancer cells, and the level of this protein is increased in many cancer cells to adapt them to the microenvironment conditions including hypoxia, nutrient depletion, and acidosis. The physiological function of eEF2K and its role in the development and progression of cancer are here reviewed in detail. In addition, a summary of progress for in vitro eEF2K inhibitors from anti-cancer drug discovery research in recent years, along with their structure-activity relationships (SARs) and synthetic routes or natural sources, is also described. Special attention is given to those inhibitors that have been already validated in vivo, with the overall aim to provide reference context for the further development of new first-in-class anti-cancer drugs that target eEF2K.

Grape Seed Proanthocyanidins Induce Apoptosis and Cell Cycle Arrest of HepG2 Cells Accompanied by Induction of the MAPK Pathway and NAG-1

Hepatocellular carcinoma (HCC) is one of the common malignancies leading to death. Although radiotherapy and chemotherapy have certain effects, their side effects limit their therapeutic effect. Phytochemicals have recently been given more attention as promising resources for cancer chemoprevention or chemotherapy due to their safety. In this study, the effects of grape seed proanthocyanidins (GSPs) on the apoptosis, cell cycle, and mitogen-activated protein kinase (MAPK) pathway-related proteins and non-steroidal anti-inflammatory drug-activated gene-1 (NAG-1) expression of HepG2 cells were investigated. The results showed that GSPs inhibited the viability of HepG2 cells in a time- and dose-dependent manner, induced apoptosis and G2/M phase cell cycle arrest, and regulated cell cycle-related proteins, cyclin B1, cyclin-dependent kinase 1, and p21. GSPs also increased reactive oxygen species production and caspase-3 activity. In addition, GSPs also increased the expression of p-ERK, p-JNK, p-p38 MAPK and NAG-1, and GSPs-induced NAG-1 expression was related to the MAPK pathway-related proteins. These data suggest that GSPs may be promising phytochemicals for HCC chemoprevention or chemotherapy.

Drug repositioning in head and neck squamous cell carcinoma: An integrated pathway analysis based on connectivity map and differential gene expression

The severe damage to health and social burden caused by head and neck squamous cell carcinoma (HNSCC) generated an urgent need to develop novel anti-cancer therapy. Currently, drug repositioning has risen in responses to the proper time as an efficient approach to invention of new anti-cancer therapies. In the present study, we aimed to screen candidate drugs for HNSCC by integrating HNSCC-related pathways from differentially expressed genes (DEGs) and drug-affected pathways from connectivity map (CMAP). We also endeavored to unveil the molecular mechanism of HNSCC through creating drug-target network and protein-to-protein (PPI) network of component DEGs in key overlapping pathways. As a result, a total of 401 DEGs were obtained from TCGA and GTEx mRNA-seq data. Taking the intersection part of 27 HNSCC-related Kyoto Encyclopedia of Genes and Genomes pathways and 33 drug-affected pathways, we retained 22 candidate drugs corresponding to two key pathways (cell cycle and p53 signaling pathways) of the five overlapping pathways. Two of the hub genes (PCNA and CCND1) identified from the PPI network of component DEGs in cell cycle and p53 signaling pathways were defined as the critical targets of candidate drugs with increased protein expression in HNSCC tissues, which was reported by the human protein atlas (HPA) database and cBioPortal. Finally, we validated via molecular docking analysis that two drugs with unknown effects in HNSCC: MG-262 and bepridil might perturb the development of HNSCC through targeting PCNA. These candidate drugs possessed broad application prospect as medication for HNSCC.

Rottlerin inhibits cell growth and invasion via down-regulation of EZH2 in prostate cancer

Rottlerin as a natural agent, which is isolated from Mallotus philippinensis, has been identified to play a critical role in tumor inhibition. However, the molecular mechanism of rottlerin-mediated anti-tumor activity is still ambiguous. It has been reported that EZH2 exhibits oncogenic functions in a variety of human cancers. Therefore, inhibition of EZH2 could be a promising strategy for the treatment of human cancers. In this study, we aim to explore whether rottlerin could inhibit tumorigenesis via suppression of EZH2 in prostate cancer cells. Multiple approaches such as FACS, Transwell invasion assay, RT-PCR, Western blotting, and transfection were performed to determine our aim. We found that rottlerin treatment led to inhibition of cell growth, migration and invasion, but induction of apoptosis in prostate cancer cells. Importantly, we defined that rottlerin decreased the expression of EZH2 and H3K27me3 in prostate cancer cells. Moreover, overexpression of EZH2 abrogated the rottlerin-induced inhibition of cell growth, migration, and invasion in prostate cancer cells. Consistently, down-regulation of EZH2 enhanced rottlerin-triggered anti-tumor function. Collectively, our work demonstrated that rottlerin exerted its tumor suppressive function via inhibition of EZH2 expression in prostate cancer cells. Our findings indicated that rottlerin might be a potential therapeutic compound for treating patients with prostate cancer.

Rottlerin inhibits cell growth, induces apoptosis and cell cycle arrest, and inhibits cell invasion in human hepatocellular carcinoma

Rottlerin, a polyphenolic compound, has been demonstrated to exhibit antitumor activity in various types of human cancer. Several studies have revealed that rottlerin exerts its anticancer function through PKC‑dependent and independent pathways. The transcriptional co‑activator with PDZ‑binding motif (TAZ) oncopreotein is an important molecule in regulation of the Hippo pathway in human cancer. The present study investigated whether rottlerin has a tumor suppressive role via inhibiting the expression of TAZ, using cell viability assay, apoptosis and cell cycle analyses, western blot analysis and Tanswell invasion assay. The results demonstrated that rottlerin suppressed cell growth, triggered cell apoptosis and induced cell cycle arrest. In addition, rottlerin inhibited cell migration and invasion in hepatocellular carcinoma (HCC) cells. Mechanistically, the results demonstrated that rottlerin exerted its antitumor activity partly through the inhibition of TAZ. In addition, the depletion of TAZ led to inhibited cell growth and invasion, whereas the overexpression of TAZ enhanced cell growth and invasion in the HCC cells. Taken together, these findings indicated that the inhibition of TAZ by rottlerin may be a novel strategy for treating HCC.

Inhibition of Notch-1 pathway is involved in rottlerin-induced tumor suppressive function in nasopharyngeal carcinoma cells

Recent studies have revealed that rottlerin is a natural chemical drug to exert its anti-cancer activity. However, the molecular mechanisms of rottlerin-induced tumor suppressive function have not been fully elucidated. Notch signaling pathway has been characterized to play a crucial role in tumorigenesis. Therefore, regulation of Notch pathway could be beneficial for the treatment of human cancer. The aims of our current study were to explore whether rottlerin could suppress Notch-1 expression, which leads to inhibition of cell proliferation, migration and invasion in nasopharyngeal carcinoma cells. We performed several approaches, such as CTG, Flow cytometry, scratch healing assay, transwell and Western blotting. Our results showed that rottlerin treatment inhibited cell growth, migration and invasion, and triggered apoptosis, and arrested cell cycle to G1 phase. Moreover, the expression of Notch-1 was obvious decreased in nasopharyngeal carcinoma cells after rottlerin treatment. Importantly, overexpression of Notch-1 promoted cell growth and invasion, whereas down-regulation of Notch-1 inhibited cell growth and invasion in nasopharyngeal carcinoma cells. Notably, we found the over-expression of Notch-1 could abrogate the anti-cancer function induced by rottlerin. Strikingly, our study implied that Notch-1 could be a useful target of rottlerin for the prevention and treatment of human nasopharyngeal carcinoma.

Isochaihulactone-induced DDIT3 causes ER stress-PERK independent apoptosis in glioblastoma multiforme cells

The endoplasmic reticulum (ER) is a major site of cellular homeostasis regulation. Under the ER stress condition, Glioblastoma multiform (GBM) cells activate the unfolded protein response. In this study, we discovered isochaihulactone, a natural compound extracted from the Chinese traditional herb Nan-Chai-Hu, which can disrupt ER homeostasis in GBM cell lines. It can induce DNA damage inducible transcript 3 (DDIT3) expression which is independent of 78 kDa glucose-regulated protein (GRP78) and protein kinase RNA-like endoplasmic reticulum kinase (PERK) expression. Flow cytometry results revealed that isochaihulactone trigger the cell cycle arrest at G2/M phase and apoptosis in GBM cells. Isochaihulactone induced DDIT3 led to the expression of NAG-1. The in vivo study showed that isochaihulactone suppressed tumor growth, and DDIT3 and Caspase3 overexpressed in the xenograft model, which is consistent with the in vitro study. Overall, the data revealed that isochaihulactone disrupted ER homeostasis in cancer cells by increasing DDIT3 and NAG-1 expression. Our finding also provides a therapeutic strategy by using isochaihulactone for GBM treatment.

Tolfenamic Acid Inhibits the Proliferation, Migration, and Invasion of Nasopharyngeal Carcinoma: Involvement of p38-Mediated Down-Regulation of Slug

PURPOSE

Tolfenamic acid (TA), a non-steroidal anti-inflammatory drug, is known to exhibit antitumor effects in various cancers apart from nasopharyngeal cancer (NPC). NPC exhibits high invasiveness, as well as metastatic potential, and patients continue to suffer from residual, recurrent, or metastatic disease even after chemoradiation therapy. Therefore, new treatment strategies are needed for NPC. In this study, we investigated the efficacy and molecular mechanisms of TA in NPC treatment.

MATERIALS AND METHODS

TA-induced cell death was detected by cell viability assay in the NPC cell lines, HNE1 and HONE1. Wound healing assay, invasion assay, and Western blot analysis were used to evaluate the antitumor effects of TA in NPC cell lines.

RESULTS

Treatment with TA suppressed the migration and invasion of HNE1 and HONE1 cells. Hepatocyte growth factor enhanced the proliferation, migration, and invasion abilities of NPC cells. This enhancement was successfully inhibited by TA treatment. Treatment with TA increased phosphorylation of p38, and the inhibition of p38 with SB203580 reversed the cytotoxic, anti-invasive, and anti-migratory effects of TA treatment in NPC cell lines. Moreover, inhibition of p38 also reversed the decrease in expression of Slug that was induced by TA treatment.

CONCLUSION

In conclusion, the activation of p38 plays a role in mediating TA-induced cytotoxicity and inhibition of invasion and migration via down-regulation of Slug.

FTY720 enhances TRAIL-mediated apoptosis by up-regulating DR5 and down-regulating Mcl-1 in cancer cells

FTY720, Fingolimod, is a functional antagonist to the sphingosine-1-phosphate (S1P) receptor and an inhibitor of sphingosine kinase 1. Here, we showed that a combination of FTY720 and TRAIL induced apoptosis in human renal, breast, and colon carcinoma cells. Most importantly, this combination had no effect on normal cells. Furthermore, the combined treatment with FTY720 and TRAIL reduced tumor growth in xenograft models. FTY720 up-regulated death receptor (DR)5 at post-translational level. Knockdown of DR5 markedly blocked apoptosis induced by the combined treatment. FTY720 also inhibited Mcl-1 expression at the post-translational level. Over-expression of Mcl-1 blocked apoptosis induced by FTY720 and TRAIL. Interestingly, phospho-FTY720 and inhibitors of sphingosine kinase failed to enhance TRAIL-induced apoptosis. Thus, FTY720 enables TRAIL-induced apoptosis through up-regulation of DR5 and down-regulation of Mcl-1 in human cancer cells.

Disruptive environmental chemicals and cellular mechanisms that confer resistance to cell death

Cell death is a process of dying within biological cells that are ceasing to function. This process is essential in regulating organism development, tissue homeostasis, and to eliminate cells in the body that are irreparably damaged. In general, dysfunction in normal cellular death is tightly linked to cancer progression. Specifically, the up-regulation of pro-survival factors, including oncogenic factors and antiapoptotic signaling pathways, and the down-regulation of pro-apoptotic factors, including tumor suppressive factors, confers resistance to cell death in tumor cells, which supports the emergence of a fully immortalized cellular phenotype. This review considers the potential relevance of ubiquitous environmental chemical exposures that have been shown to disrupt key pathways and mechanisms associated with this sort of dysfunction. Specifically, bisphenol A, chlorothalonil, dibutyl phthalate, dichlorvos, lindane, linuron, methoxychlor and oxyfluorfen are discussed as prototypical chemical disruptors; as their effects relate to resistance to cell death, as constituents within environmental mixtures and as potential contributors to environmental carcinogenesis.

The H6D genetic variation of GDF15 is associated with genesis, progress and prognosis in colorectal cancer

BACKGROUND

Growth differentiation factor 15 (GDF15) plays important roles in the carcinogenesis of many types of tumors. The aim of this study was to investigate whether H6D polymorphism is contributed to the genesis, progress and prognosis of colorectal cancer (CRC) in Chinese population.

METHODS

Pyrosequencing was used to determine the H6D genotypes. The relationship between the genotypes and clinical characteristics was analyzed.

RESULTS

The frequency of CG+GG genotype in the GDF15 H6D polymorphism was significantly increased in CRC patients when compared with controls [odds ratio (OR), 1.543; 95% confidence interval (95% CI), 1.138-2.094, P=0.005]. We also found that the patients with CG+GG genotype had an increased risk of death from colon cancer than those carrying homozygote CC [hazard ratio (HR), 2.472; 95% CI, 1.172-5.214; P=0.017] and the patients with CG+GG genotype of colon cancer also have a positive correlation with distant metastasis than those carrying homozygote CC (χ(2)=4.087, P=0.043). For the first time, H6D was also identified as somatic mutation when compared the H6D genotype in tumor tissues and their matched normal tissues, and the mutation rate is 7.2%. The male CRC patients with the H6D mutation were susceptible to distant metastasis (P=0.028, χ(2)=4.820) and had a relatively poor prognosis.

CONCLUSION

Our results suggest that the H6D genetic variant may be considered as a biomarker of tumorgenesis, metastasis and prognosis in colorectal cancer in Chinese population.

The oncogene EVI1 enhances transcriptional and biological responses of human myeloid cells to all-trans retinoic acid

The product of the ecotropic virus integration site 1 (EVI1) gene, whose overexpression is associated with a poor prognosis in myeloid leukemias and some epithelial tumors, regulates gene transcription both through direct DNA binding and through modulation of the activity of other sequence specific transcription factors. Previous results from our laboratory have shown that EVI1 influenced transcription regulation in response to the myeloid differentiation inducing agent, all-trans retinoic acid (ATRA), in a dual manner: it enhanced ATRA induced transcription of the RARβ gene, but repressed the ATRA induction of the EVI1 gene itself. In the present study, we asked whether EVI1 would modulate the ATRA regulation of a larger number of genes, as well as biological responses to this agent, in human myeloid cells. U937 and HL-60 cells ectopically expressing EVI1 through retroviral transduction were subjected to microarray based gene expression analysis, and to assays measuring cellular proliferation, differentiation, and apoptosis. These experiments showed that EVI1 modulated the ATRA response of several dozens of genes, and in fact reinforced it in the vast majority of cases. A particularly strong synergy between EVI1 and ATRA was observed for GDF15, which codes for a member of the TGF-β superfamily of cytokines. In line with the gene expression results, EVI1 enhanced cell cycle arrest, differentiation, and apoptosis in response to ATRA, and knockdown of GDF15 counteracted some of these effects. The potential clinical implications of these findings are discussed.

Phosphorylation-independent mTORC1 inhibition by the autophagy inducer Rottlerin

We recently found that Rottlerin not only inhibits proliferation but also causes Bcl-2- and Beclin 1-independent autophagic death in apoptosis-resistant breast adenocarcinoma MCF-7 cells. Having excluded a role for canonical signaling pathways, the current study was aimed to investigate the contribution of the AMPK/mTOR axis in autophagy induction and to search for the upstream signaling molecules potentially targeted by Rottlerin. Using several enzyme inhibitors, Western blotting analysis, mTOR siRNA and pull down assay, we demonstrate that the Rottlerin-triggered autophagy is mediated by inhibition of mTORC1 activity through a novel AMPK and mTORC1 phosphorylation-independent mechanism, likely mediated by the direct interaction between Rottlerin and mTOR.

Integrative Pathway Analysis Using Graph-Based Learning with Applications to TCGA Colon and Ovarian Data

Recent method development has included multi-dimensional genomic data algorithms because such methods have more accurately predicted clinical phenotypes related to disease. This study is the first to conduct an integrative genomic pathway-based analysis with a graph-based learning algorithm. The methodology of this analysis, graph-based semi-supervised learning, detects pathways that improve prediction of a dichotomous variable, which in this study is cancer stage. This analysis integrates genome-level gene expression, methylation, and single nucleotide polymorphism (SNP) data in serous cystadenocarcinoma (OV) and colon adenocarcinoma (COAD). The top 10 ranked predictive pathways in COAD and OV were biologically relevant to their respective cancer stages and significantly enhanced prediction accuracy and area under the ROC curve (AUC) when compared to single data-type analyses. This method is an effective way to simultaneously predict binary clinical phenotypes and discover their biological mechanisms.

FZD1 activates protein kinase C delta-mediated drug-resistance in multidrug-resistant MES-SA/Dx5 cancer cells

Multidrug-resistant (MDR) cancer is a major clinical problem in chemotherapy of cancer patients. We have noted inappropriate PKCδ hypomethylation and overexpression of genes in the PKCδ/AP-1 pathway in the human uterus sarcoma drug-resistant cell line, MES-SA/Dx5 cells, which also overexpress p-glycoprotein (ABCB1). Recent studies have indicated that FZD1 is overexpressed in both multidrug-resistant cancer cell lines and in clinical tumor samples. These data have led us to hypothesize that the FZD1-mediated PKCδ signal-transduction pathway may play an important role in drug resistance in MES-SA/Dx5 cells. In this work, the PKCδ inhibitor Rottlerin was found to reduce ABCB1 expression and to inhibit the MDR drug pumping ability in the MES-SA/Dx5 cells when compared with the doxorubicin-sensitive parental cell line, MES-SA. PKCδ was up-regulated with concurrent up-regulation of the mRNA levels of the AP-1-related factors, c-JUN and c-FOS. Activation of AP-1 also correlated with up-regulation of the AP-1 downstream genes HGF and EGR1. Furthermore, AP-1 activities were reduced and the AP-1 downstream genes were down-regulated in Rottlerin-treated or PKCδ shRNA-transfected cells. MES-SA/Dx5 cells were resensitized to doxorubicin-induced toxicity by co-treatment with doxorubicin and Rottlerin or PKCδ shRNA. In addition, cell viability and drug pump-out ability were significantly reduced in the FZD1 inhibitor curcumin-treated and FZD1 shRNA-knockdown MES-SA/Dx5 cells, indicating involvement of PKCδ in FZD1-modulated ABCB1 expression pathway. Taken together, our data demonstrate that FZD1 regulates PKCδ, and the PKCδ/AP-1 signalling transduction pathway plays an important role in drug resistance in MES-SA/Dx5 cells.

Rottlerin induces Wnt co-receptor LRP6 degradation and suppresses both Wnt/β-catenin and mTORC1 signaling in prostate and breast cancer cells

Activation of Wnt/β-catenin signaling can result in up-regulation of mTORC1 signaling in cancer cells. The low density lipoprotein receptor-related protein-6 (LRP6) is an essential Wnt co-receptor for Wnt/β-catenin signaling. We found that rottlerin, a natural plant polyphenol, suppressed LRP6 expression and phosphorylation, and inhibited Wnt/β-catenin signaling in HEK293 cells. Furthermore, the inhibitory effects of rottlerin on LRP6 expression/phosphorylation and Wnt/β-catenin signaling were confirmed in human prostate cancer PC-3 and DU145 cells and breast cancer MDA-MB-231 and T-47D cells. Mechanistically, rottlerin promoted LRP6 degradation, but had no effects on LRP6 transcriptional activity. In addition, rottlerin-mediated LRP6 down-regulation was unrelated to activation of 5'-AMP-activated protein kinase (AMPK). Importantly, we also found that rottlerin inhibited mTORC1 signaling in prostate and breast cancer cells. Finally, we demonstrated that rottlerin was able to suppress the expression of cyclin D1 and survivin, two targets of both Wnt/β-catenin and mTORC1 signaling, in prostate and breast cancer cells, and displayed remarkable anticancer activity with IC(50) values between 0.7 and 1.7 μM for prostate cancer PC-3 and DU145 cells and breast cancer MDA-MB-231 and T-47D cells. The IC(50) values are comparable to those shown to suppress the activities of Wnt/β-catenin and mTORC1 signaling in prostate and breast cancer cells. Our data indicate that rottlerin is a novel LRP6 inhibitor and suppresses both Wnt/β-catenin and mTORC1 signaling in prostate and breast cancer cells, and that LRP6 represents a potential therapeutic target for cancers.

p38 and JNK MAPK pathways control the balance of apoptosis and autophagy in response to chemotherapeutic agents

The Mitogen Activated Protein Kinase (MAPK) signaling plays a critical role in the outcome and the sensitivity to anticancer therapies. Activated MAPK can transmit extracellular signals to regulate cell growth, proliferation, differentiation, migration, apoptosis and so on. Apoptosis as well as macroautophagy (hereafter referred to as autophagy) can be induced by extracellular stimuli such the treatment of chemotherapeutic agents, resulting in different cell response to these drugs. However, the molecular mechanisms mediating these two cellular processes remain largely unknown. Recently, several studies provide new insights into p38 and JNK MAPK pathways function in the control of the balance of autophagy and apoptosis in response to genotoxic stress. Our increased understanding of the role of p38 and JNK MAPK pathways in regulating the balance of autophagy and apoptosis will hopefully provide prospective strategies for cancer therapy.