scholarly journals The MAPK hypothesis: immune-regulatory effects of MAPK-pathway genetic dysregulations and implications for breast cancer immunotherapy

2017 ◽  
Vol 1 (5) ◽  
pp. 429-445 ◽  
Author(s):  
Davide Bedognetti ◽  
Jessica Roelands ◽  
Julie Decock ◽  
Ena Wang ◽  
Wouter Hendrickx

With the advent of checkpoint inhibition, immunotherapy has revolutionized the clinical management of several cancers, but has demonstrated limited efficacy in mammary carcinoma. Transcriptomic profiling of cancer samples defined distinct immunophenotypic categories characterized by different prognostic and predictive connotations. In breast cancer, genomic alterations leading to the dysregulation of mitogen-activated protein kinase (MAPK) pathways have been linked to an immune-silent phenotype associated with poor outcome and treatment resistance. These aberrations include mutations of MAP3K1 and MAP2K4, amplification of KRAS, BRAF, and RAF1, and truncations of NF1. Anticancer therapies targeting MAPK signaling by BRAF and MEK inhibitors have demonstrated clear immunologic effects. These off-target properties could be exploited to convert the immune-silent tumor phenotype into an immune-active one. Preclinical evidence supports that MAPK-pathway inhibition can dramatically increase the efficacy of immunotherapy. In this review, we provide a detailed overview of the immunomodulatory impact of MAPK-pathway blockade through BRAF and MEK inhibitions. While BRAF inhibition might be relevant in melanoma only, MEK inhibition is potentially applicable to a wide range of tumors. Context-dependent similarities and differences of MAPK modulation will be dissected, in light of the complexity of the MAPK pathways. Therapeutic strategies combining the favorable effects of MAPK-oriented interventions on the tumor microenvironment while maintaining T-cell function will be presented. Finally, we will discuss recent studies highlighting the rationale for the implementation of MAPK-interference approaches in combination with checkpoint inhibitors and immune agonists in breast cancer.

PPAR Research ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Seung-Won Park ◽  
Chunghee Cho ◽  
Byung-Nam Cho ◽  
Youngchul Kim ◽  
Tae Won Goo ◽  
...  

15-Deoxy-Δ12,14-prostaglandin J2(15d-PGJ2) and activin are implicated in the control of apoptosis, cell proliferation, and inflammation in cells. We examined both the mechanism by which 15d-PGJ2regulates the transcription of activin-induced activin receptors (ActR) and Smads in HepG2 cells and the involvement of the nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) pathways in this regulation. Activin A (25 ng/mL) inhibited HepG2 cell proliferation, whereas 15d-PGJ2(2 μM and 5 μM) had no effect. Activin A and 15d-PGJ2showed different regulatory effects on ActR and Smad expression, NF-κB p65 activity and MEK/ERK phosphorylation, whereas they both decreased IL-6 production and increased IL-8 production. When co-stimulated with 15d-PGJ2and activin, 15d-PGJ2inhibited the activin-induced increases in ActR and Smad expression, and decreased activin-induced IL-6 production. However, it increased activin-induced IL-8 production. In addition, 15d-PGJ2inhibited activin-induced NF-κB p65 activity and activin-induced MEK/ERK phosphorylation. These results suggest that 15d-PGJ2suppresses activin-induced ActR and Smad expression, down-regulates IL-6 production, and up-regulates IL-8 production via suppression of NF-κB and MAPK signaling pathway in HepG2 cells. Regulation of ActR and Smad transcript expression and cytokine production involves NF-κB and the MAPK pathway via interaction with 15d-PGJ2/activin/Smad signaling.


2017 ◽  
Author(s):  
Helma Zecena ◽  
Daniel Tveit ◽  
Zi Wang ◽  
Ahmed Farhat ◽  
Parvita Panchal ◽  
...  

AbstractKinase inhibition in the mitogen activated protein kinase (MAPK) pathway is a standard therapy for cancer patients with activating BRAF mutations. However, the anti-tumorigenic effect and clinical benefit are only transient, and tumors are prone to treatment resistance and relapse. To elucidate mechanistic insights into drug resistance, we have established an in vitro cellular model of MAPK inhibitor resistance in malignant melanoma. The cellular model evolved in response to clinical dosage of BRAF inhibitor, vemurafenib, PLX4032. We conducted transcriptomic expression profiling using RNA-Seq and RT-qPCR arrays. Pathways of melanogenesis, MAPK signaling, cell cycle, and metabolism were significantly enriched among the set of differentially expressed genes of vemurafenib-resistant cells vs control. The underlying mechanism of treatment resistance and pathway rewiring based on non-genomic adaptation was validated in two distinct melanoma models, SK-MEL-28 and A375. Both cell lines have activating BRAF mutations and display metastatic potential. Downregulation of tumor suppressors and negative MAPK regulators, dual specific phosphatases, reengages mitogenic signaling. Upregulation of growth factors or cytokine receptors triggers signaling pathways circumventing BRAF blockage. Changes in amino acid and one-carbon metabolism support cellular proliferation despite MAPK inhibitor treatment. In addition, an upregulation of pigmentation in inhibitor resistant melanoma cells was observed. Cellular pathways utilized during inhibitor resistance promoted melanogenesis, a pathway which partially overlaps with MAPK signaling. Upstream regulator analysis suggested gene expression changes of forkhead box and hypoxia inducible factor family transcription factors. The established cellular models offer mechanistic insight into cellular changes and therapeutic targets under inhibitor resistance in malignant melanoma. At a systems biology level, the MAPK pathway undergoes major rewiring while acquiring inhibitor resistance. The outcome of this transcriptional plasticity is selection for a set of transcriptional master regulators, which circumvent upstream targeted kinases and provide alternative routes of mitogenic activation. A fine-woven network of redundant signals maintains similar effector genes allowing for tumor cell survival and malignant progression in therapy resistant cancer.


2016 ◽  
Vol 113 (11) ◽  
pp. 3030-3035 ◽  
Author(s):  
Saya H. Ebbesen ◽  
Maurizio Scaltriti ◽  
Carl U. Bialucha ◽  
Natasha Morse ◽  
Edward R. Kastenhuber ◽  
...  

Loss of the tumor suppressor gene PTEN is implicated in breast cancer progression and resistance to targeted therapies, and is thought to promote tumorigenesis by activating PI3K signaling. In a transgenic model of breast cancer, Pten suppression using a tetracycline-regulatable short hairpin (sh)RNA cooperates with human epidermal growth factor receptor 2 (HER2/neu), leading to aggressive and metastatic disease with elevated signaling through PI3K and, surprisingly, the mitogen-activated protein kinase (MAPK) pathway. Restoring Pten function is sufficient to down-regulate both PI3K and MAPK signaling and triggers dramatic tumor regression. Pharmacologic inhibition of MAPK signaling produces similar effects to Pten restoration, suggesting that the MAPK pathway contributes to the maintenance of advanced breast cancers harboring Pten loss.


2005 ◽  
Vol 23 (27) ◽  
pp. 6771-6790 ◽  
Author(s):  
Muralidhar Beeram ◽  
Amita Patnaik ◽  
Eric K. Rowinsky

The mitogen-activated protein kinase (MAPK) signaling pathway plays a critical role in transmitting proliferative signals generated by cell surface receptors and cytoplasmic signaling elements to the nucleus. Several important signaling elements of the MAPK pathway, particularly Ras and Raf, are encoded by oncogenes, and as such, their structures and functions can be modified, rendering them constitutively active. Because the MAPK pathway is dysregulated in a notable proportion of human malignancies, many of its aberrant and critical components represent strategic targets for therapeutic development against cancer. Raf, which is an essential serine/threonine kinase constituent of the MAPK pathway and a downstream effector of the central signal transduction mediator Ras, is activated in a wide range of human malignancies by aberrant signaling upstream of the protein (eg, growth factor receptors and mutant Ras) and activating mutations of the protein itself, both of which confer a proliferative advantage. Three isoforms of Raf have been identified, and therapeutics targeting Raf, including small-molecule inhibitors and antisense oligodeoxyribonucleotides (ASON), are undergoing clinical evaluation. The outcomes of these investigations may have far-reaching implications in the management of many types of human cancer. This review outlines the structure and diverse functions of Raf, the rationale for targeting Raf as a therapeutic strategy against cancer, and the present status of various therapeutic approaches including ASONs and small molecules, particularly sorafenib (BAY 43-9006).


2019 ◽  
Vol 20 (10) ◽  
pp. 2490 ◽  
Author(s):  
Wen-Chung Huang ◽  
Chun-Hsun Huang ◽  
Sindy Hu ◽  
Hui-Ling Peng ◽  
Shu-Ju Wu

Atopic dermatitis (AD) is a recurrent allergic skin disease caused by genetic and environmental factors. Patients with AD may experience immune imbalance, increased levels of mast cells, immunoglobulin (Ig) E and pro-inflammatory factors (Cyclooxygenase, COX-2 and inducible NO synthase, iNOS). While spilanthol (SP) has anti-inflammatory and analgesic activities, its effect on AD remains to be explored. To develop a new means of SP, inflammation-related symptoms of AD were alleviated, and 2,4-dinitrochlorobenzene (DNCB) was used to induce AD-like skin lesions in BALB/c mice. Histopathological analysis was used to examine mast cells and eosinophils infiltration in AD-like skin lesions. The levels of IgE, IgG1 and IgG2a were measured by enzyme-linked immunosorbent assay (ELISA) kits. Western blot was used for analysis of the mitogen-activated protein kinase (MAPK) pathways and COX-2 and iNOS protein expression. Topical SP treatment reduced serum IgE and IgG2a levels and suppressed COX-2 and iNOS expression via blocked mitogen-activated protein kinase (MAPK) pathways in DNCB-induced AD-like lesions. Histopathological examination revealed that SP reduced epidermal thickness and collagen accumulation and inhibited mast cells and eosinophils infiltration into the AD-like lesions skin. These results indicate that SP may protect against AD skin lesions through inhibited MAPK signaling pathways and may diminish the infiltration of inflammatory cells to block allergic inflammation.


2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 1034-1034
Author(s):  
Justin Wayne Wong Tiu-lim ◽  
Jun Yin ◽  
Joanne Xiu ◽  
Wolfgang Michael Korn ◽  
Heinz-Josef Lenz ◽  
...  

1034 Background: The Ras-MAPK pathway is a known driver of tumorigenesis and therapeutic target in a variety of cancers. Alterations in this pathway have been linked to decreased tumor immunogenicity. However, molecular alterations in the Ras-MAPK are rare in breast cancer (BC) and their clinical implications remain unclear. As mutational status does not accurately correlate with transcriptional activity, a MAPK pathway activity score (MPAS, Wagle et al., 2018, npj Precision Medicine) is indicative of MAPK activation and correlates with response to MEK (MEKi) or BRAF inhibition (BRAFi). Our goal was to determine the frequency of molecular alterations in the Ras-MAPK and correlate to MAPK pathway activation in MBC. Methods: A total of 6464 BC samples underwent comprehensive molecular profiling at Caris Life Sciences. Analyses included next generation sequencing of DNA (592 Gene Panel, NextSeq; whole exome sequencing, NovaSEQ), RNA (NovaSeq, whole transcriptome sequencing, WTS) and IHC. MPAS and immune cell fraction (ICF, Quantiseq) were assessed by mRNA analysis. Wilcoxon, Fisher’s exact, or Dunnett’s test was used. All results shown were statistically significant (p < 0.05). Results: The predominant alteration of RAS genes was mutation followed by amplification, no fusions were detected (Table). Only 0.17% of all tumors harbor KRAS G12c mutations. The highest MPAS scores were found in KRAS mutants (mut), HRAS mut (Q61, G1213), BRAF V600 (class 1) mut and NRAS Q61 mut (Table) and therefore used to define Genomic MAPK Activated Tumors (GMAT). GMAT compared to wild type (WT) had significantly higher PD-L1 expression, TMB and MSI/dMMR. GMAT had less B cells (3.4% vs 4.4%), more M1 Macrophages (4.4% vs 3.4%) and neutrophils (5.5% vs 2.7%) regardless of HR status but less NK cells (2.3% s 3.0%), MSDCs (0.9% vs 3.0%) only in HR- tumors with respect to WT. GMAT tumors showed more frequent mutation rate (mr) of PIK3CA (HR+: 57.3% vs 40%; HR-: 41.9% vs 17.9%). HR+ tumors had a higher mr of MSH3 (11.8% vs 0.6%) while HR- tumors had higher mr of PIK3R1 (9.6% vs 3.8%), RhoA (5.3% vs 0.5%), DNA repair genes (TERT, 18.2% vs 1.0%; ARID1A, 18.2% vs 5.9%; PRKDC, 3.9% vs 0) and lower TP53 mr (54.5% vs 85.8%) compared to WT. Conclusions: Our study demonstrates that RAS, BRAF and MEK1 mutations are associated with MAPK pathway activation indicative of benefit from MEKi or BRAFi. GMAT warrant further investigation for combinations targeting the RAS-MAPK pathway and immune checkpoint inhibitors.[Table: see text]


2011 ◽  
Vol 300 (1) ◽  
pp. E103-E110 ◽  
Author(s):  
Xiaoban Xin ◽  
Lijun Zhou ◽  
Caleb M. Reyes ◽  
Feng Liu ◽  
Lily Q. Dong

The adaptor protein APPL1 mediates the stimulatory effect of adiponectin on p38 mitogen-activated protein kinase (MAPK) signaling, yet the underlying mechanism remains unclear. Here we show that, in C2C12 cells, overexpression or suppression of APPL1 enhanced or suppressed, respectively, adiponectin-stimulated p38 MAPK upstream kinase cascade, consisting of transforming growth factor-β-activated kinase 1 (TAK1) and mitogen-activated protein kinase kinase 3 (MKK3). In vitro affinity binding and coimmunoprecipitation experiments revealed that TAK1 and MKK3 bind to different regions of APPL1, suggesting that APPL1 functions as a scaffolding protein to facilitate adiponectin-stimulated p38 MAPK activation. Interestingly, suppressing APPL1 had no effect on TNFα-stimulated p38 MAPK phosphorylation in C2C12 myotubes, indicating that the stimulatory effect of APPL1 on p38 MAPK activation is selective. Taken together, our study demonstrated that the TAK1-MKK3 cascade mediates adiponectin signaling and uncovers a scaffolding role of APPL1 in regulating the TAK1-MKK3-p38 MAPK pathway, specifically in response to adiponectin stimulation.


2019 ◽  
Author(s):  
Sukanya Basu ◽  
Beatriz González ◽  
Boyang Li ◽  
Garrett Kimble ◽  
Keith G. Kozminski ◽  
...  

ABSTRACTRho GTPases regulate cell polarity and signal transduction pathways to control morphogenetic responses in different settings. In yeast, the Rho GTPase Cdc42p regulates cell polarity, and through the p21-activated kinase Ste20p, Cdc42p also regulates mitogen-activated protein kinase (MAPK) pathways (mating, filamentous growth or fMAPK, and HOG). Although much is known about how Cdc42p regulates cell polarity and the mating pathway, how Cdc42p regulates the fMAPK pathway is not clear. To address this question, Cdc42p-dependent MAPK pathways were compared in the filamentous (∑1278b) strain background. Each MAPK pathway showed a unique activation profile, with the fMAPK pathway exhibiting slow activation kinetics compared to the mating and HOG pathways. A previously characterized version of Cdc42p, Cdc42pE100A, that is specifically defective for fMAPK pathway signaling, was defective for interaction with Bem4p, the pathway-specific adaptor for the fMAPK pathway. Corresponding residues in Bem4p were identified that were required for interaction with Cdc42p and fMAPK pathway signaling. The polarity adaptor Bem1p also regulated the fMAPK pathway. In the fMAPK pathway, Bem1p recruited Ste20p to the plasma membrane, cycled between an open and closed conformation, and interacted with the GEF for Cdc42, Cdc24p. Bem1p also regulated effector pathways in different ways, behaving as a multi-functional adaptor in some pathways and an inert scaffold in others. Genetic suppression tests showed that Bem4p and Bem1p regulate the fMAPK pathway in an ordered sequence. Collectively, the study demonstrates unique and sequential functions for Rho GTPase adaptors in regulating MAPK pathways.HIGHLIGHTSComparing Cdc42p-dependent MAPK pathways showed that the fMAPK pathway had slow activation kinetics compared to the mating and HOG pathways.A collection of cdc42 alleles was tested for MAPK pathway functions. § Cdc42pE100A, previously characterized as being specifically defective for fMAPK signaling, showed reduced interaction with the fMAPK pathway adaptor Bem4p.§ Corresponding residues in Bem4p were identified that were required for interaction with Cdc42p and fMAPK signaling.The polarity adaptor Bem1p regulated the fMAPK pathway. § Bem1p regulated the fMAPK pathway by recruiting Ste20p to the plasma membrane, cycling between an open and closed conformation, and interacting with the Cdc42p GEF, Cdc24p.Different domains of Bem1p had different roles in regulating effector pathways. § Bem1p may function as a multi-functional adaptor in some pathways and an inert scaffold in others.Bem4p and Bem1p regulated the fMAPK pathway in an ordered sequence. § The data support a model where Bem4p recruits Cdc24p to GDP-Cdc42p, and Bem1p directs GTP-Cdc42p to Ste20p at the plasma membrane.§ The bud-site GTPase Rsr1p regulates Cdc24p in the fMAPK pathway but does not initiate signaling.


2020 ◽  
Author(s):  
Sheida Jamalzadeh ◽  
Paul J. Cullen

ABSTRACTMAPK pathways regulate different responses yet can share a subset of common components. In this study, a genome-wide screen was performed to identify genes that, when overexpressed, induce a growth reporter (FUS1-HIS3) that responds to ERK-type MAPK pathways (Mating/filamentous growth or fMAPK) but not p38-type MAPK pathways (HOG) in yeast. Approximately 4,500 plasmids overexpressing individual yeast genes were introduced into strains containing the FUS1-HIS3 reporter by high-throughput transformation. Candidate genes were identified by measuring the degree of growth, which was a reflection of reporter activity. Of fourteen genes identified and validated by re-testing, two were metabolic controls (HIS3 and ATR1), five had established roles in regulating ERK-type pathways (STE4, STE7, BMH1, BMH2, MIG2) and seven represent potentially new regulators of MAPK signaling (RRN6, CIN5, MRS6, KAR2, TFA1, RSC3, RGT2). MRS6 encodes a Rab escort protein and effector of the TOR pathway that plays an established role in nutrient signaling. MRS6 overexpression stimulated filamentous/invasive growth and phosphorylation of the ERK-type fMAPK, Kss1. Overexpression of MRS6 reduced the osmotolerance of cells and phosphorylation of the p38/HOG pathway MAPK, Hog1. Mrs6 interacted with the PAK kinase Ste20 and MAPKK Ste7 by two-hybrid analysis. Collectively, the data indicate that Mrs6 may function to selectively propagate an ERK-dependent signal. Generally speaking, the identification of new MAPK pathway regulators by genetic screening in yeast may be a useful resource for understanding signaling pathway regulation.


2021 ◽  
Vol 16 (7) ◽  
pp. 231-239
Author(s):  
Muthu Kumar Thirunavukkarasu ◽  
Ramanathan Karuppasamy

Aberrant stimulation of MAPK (Mitogen-activated protein kinase) signaling pathway triggers the dysregulated cell growth and resistance to apoptosis in a wide variety of tumors especially in NSCLC (Nonsmall cell lung cancer). Most of the research is on treating lung cancer by targeting the MAPK pathway receptors. Nevertheless, it is essential to consider interconnections and mode of action to resolve the drug resistance ad feedback loops during the treatment with checkpoint inhibitors. Here we describe the overall mechanism of MAPK pathway, oncogenic mutations and precise information regarding the drug compounds for each receptor in this pathway. Further, in-depth insights into this review could be beneficial for the empathetic discovery of inhibitors for NSCLC against this pathway.


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