MAPK Pathway Components Research Articles

A Novel Lipid Nanoparticle NBF-006 Encapsulating Glutathione S-Transferase P siRNA for the Treatment of KRAS-driven Non-small Cell Lung Cancer.

Non-small cell lung cancer (NSCLC) accounts for approximately 85% of lung cancers, and KRAS mutations occur in 25-30% of NSCLC. Our approach to developing a therapeutic with the potential to target KRAS mutant NSCLC was to identify a new target involved in modulating signaling proteins in the RAS pathway. Glutathione S-Transferase P (GSTP) known as a Phase II detoxification enzyme has more recently been identified as a modulator of MAP kinase-related cell-signaling pathways. Therefore, developing a GSTP siRNA may be an effective therapeutic approach to treat KRAS mutant NSCLC. The lead drug product candidate (NBF-006) is a proprietary siRNA-based lipid nanoparticle (LNP) comprising GSTP siRNA (NDT-05-1040). Here, studies using a panel of KRAS mutant NSCLC cell lines demonstrated that NDT-05-1040 is a very potent and selective GSTP siRNA inhibitor. Our Western blot analysis showed that NDT-05-1040 effectively decreased the phosphorylation of MAPK and PI3K pathway components while upregulating apoptotic signaling cascade. Our in vivo studies revealed statistically significant higher distribution of NBF-006 to the lungs and tumor as compared to liver. In the subcutaneous and orthotopic tumor models, NBF-006 led to a statistically significant and dose dependent anti-tumor growth inhibition. Further, quantitative image analysis of PCNA and PARP staining showed that NBF-006 decreased proliferation and induced apoptosis, respectively, in tumors. Additionally, in a surgically implanted orthotopic lung tumor model, the survival rate of the NBF-006 treatment group was significantly prolonged (P <0.005) as compared to the vehicle control group. Together, these preclinical studies supported advancement of NBF-006 into clinical studies.

Abstract 944: Pre-clinical activity of the Wnt pathway inhibitor RXC004 in combination with MAPK pathway inhibitors in GI cancer models

Abstract Background: Gastrointestinal (GI) cancers cause more cancer deaths than any other body system, with 3.4 million related deaths in 2018. Wnt pathway activation is common in GI cancers, with the pathogenic upstream Wnt pathway variant sub-population (RNF43 loss of function/RSPO gain of function) showing a combined prevalence of 4.7% in GI cancer patients; pre-clinically this sub-population shows exquisite sensitivity to RXC004, a small molecule Porcupine inhibitor. A striking co-occurrence of upstream Wnt pathway variants with MAPK pathway driver mutations (KRAS, BRAF, NRAS) was detected in 77% of Microsatellite stable (MSS) GI cancers, suggesting co-inhibiting these pathways could enhance clinical activity in these patients. Methods: In vitro proliferation assays were performed in pre-clinical models of upstream Wnt pathway mutated MSS GI cancer (SNU-1411, HPAF-II and AsPC-1) using Wnt (RXC004) or MAPK (Trametinib) pathway inhibitors at multiple concentrations as single agents or in combination. Control cells with downstream Wnt pathway mutations (WiDr and HCT116) were also tested. Synergistic combination effects were detected by BLISS scores. RXC004 (1.5mg/kg QD) and Trametinib (0.3mg/kg QD) were evaluated in an RSPO-fusion xenograft model (SNU-1411) as single agents or in combination. Efficacy was measured by tumour volume and weight; PD markers were assessed in end of study tumour samples. Relative AXIN2 and DUSP6 gene expression changes were determined upon inhibitor treatment by quantitative Polymerase Chain Reaction (qPCR). Results: RXC004 in combination with Trametinib demonstrated strong anti-proliferative synergy in SNU-1411 cells and moderate synergy/additivity in HPAF-II and AsPC-1 cells; no synergy was observed in control cells. In vivo, RXC004 and Trametinib monotherapy led to significant moderate tumour growth control (p&amp;lt;0.05) at the doses tested, whereas their combination led to significantly enhanced efficacy (p&amp;lt;0.05). Gene expression analysis demonstrated a reciprocal Wnt/MAPK signaling mechanism; RXC004 strongly suppressed Wnt signaling (AXIN2) but increased MAPK signaling (DUSP6), whilst Trametinib strongly suppressed MAPK signaling (DUSP6) but increased Wnt signaling (AXIN2). Combination of RXC004 and Trametinib sustained inhibition of both Wnt and MAPK signalling. Similar effects were observed with inhibitors of other MAPK pathway components. Conclusion: Wnt and MAPK pathways are frequently co-activated in GI cancers, particularly in the upstream Wnt pathway mutated sub-population. Pre-clinically we show that Wnt and MAPK pathways act as potential reciprocal resistance mechanisms following single agent inhibition of either pathway; co-inhibition of these pathways leads to synergistic effects in vitro and enhanced efficacy in vivo. This provides a clear rationale to assess this combination approach in the clinic. Citation Format: Simon A. Woodcock, Dorottya Keppel, Catherine Eagle, James Kelly, Eimear Flanagan, Emma Bishop, Inder Bhamra, Clifford D. Jones, Richard Armer, Jane Robertson, Caroline Phillips. Pre-clinical activity of the Wnt pathway inhibitor RXC004 in combination with MAPK pathway inhibitors in GI cancer models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 944.

Oleic acid attenuates asthma pathogenesis via Th1/Th2 immune cell modulation, TLR3/4-NF-κB-related inflammation suppression, and intrinsic apoptotic pathway induction.

WHO reported that asthma was responsible for 455,000 deaths in 2019 and asthma patients was evaluated 262 million in May 2023. The incidence is expected to increase as the average life expectancy increases, highlighting asthma as a significant health challenge in an aging society. The etiology of asthma is linked to an imbalance of Th1 and Th2 cells, respiratory inflammation, and pulmonary cell proliferation. The purpose of this study is to investigate the anti-asthmatic effect and potential mechanism of oleic acid. The anti-inflammatory effect of oleic acid was evaluated in an LPS-induced RAW 264.7 cell model, and immune modulation and the anti-apoptotic effect were measured in an ovalbumin-induced BALB/c mouse model. A variety of analytical procedures, such as MTT, qPCR, ELISA, Western blotting, immunofluorescence, gene transfection, immunohistochemistry, and several staining methods (Diff Quik, H&E, PAS), were used to evaluate the effectiveness and mechanisms of these methods. The results from in vitro experiments showed that oleic acid could reduce the levels of inflammatory cytokines (TNF-α, IL-6, and IL-1β), and molecular docking studies suggested that oleic acid could interact with TLR3 and TLR4 proteins to form ligand-protein complexes, showing good binding affinity. Additionally, oleic acid attenuated the expression of MAPK pathway components (JNK, p38 MAPK) and NF-κB pathway constituents (IκB, NF-κB, COX-2, PGE2). In vivo results indicated that oleic acid reduced the levels of inflammatory cells (WBCs and eosinophils) and IgE activity, reduced the expression of the Th2 cell transcription factor GATA-3, and decreased the levels of Th2/Th17-related cytokines (IL-4, TNF-α, and IL-6). Oleic acid also alleviated OVA-induced pathological changes in the lung, such as epithelial cell proliferation, inflammatory cell infiltration, and mucus hypersecretion. OVA restored apoptosis in lung epithelial cells by modulating the expression of Bcl-2 and Bax. In summary, oleic acid has potential as a novel candidate for asthma treatment through its ability to regulate immune cells, exert anti-inflammatory effects, and promote apoptosis, thereby ameliorating asthma manifestations.

IKK/NF-κB and ROS signal axes are involved in Tenacissoside H mediated inhibitory effects on LPS-induced inflammatory osteolysis.

Periodontal disease and arthroplasty prosthesis loosening and destabilization are both associated with osteolysis, which is predominantly caused by abnormal bone resorption triggered by pro-inflammatory cytokines. Osteoclasts (OCs) are critical players in the process. Concerns regarding the long-term efficacy and side effects of current frontline therapies, however, remain. Alternative therapies are still required. The aim of this work was to investigate the involvement of Tenacissoside H (TDH) in RANKL-mediated OC differentiation, as well as inflammatory osteolysis and associated processes. In vitro, bone marrow-derived macrophages (BMMs) cultured with RANKL and M-CSF were used to detect TDH in the differentiation and function of OCs. Real-time quantitative PCR was used to measure the expression of specific genes and inflammatory factors in OCs. Western blot was used to identify NFATc1, IKK, NF-κB, MAPK pathway, and oxidative stress-related components. Finally, an LPS-mediated calvarial osteolysis mouse model was employed to explore TDH's role in inflammatory osteolysis. The results showed that in vivo TDH inhibited the differentiation and resorption functions of OCs and down-regulated the transcription of osteoclast-specific genes, as well as Il-1β, Il-6 and Tnf-α. In addition, TDH inhibited the IKK and NF-κB signalling pathways and down-regulated the level of ROS. In vivo studies revealed that TDH improves the bone loss caused by LPS. TDH may be a new candidate or treatment for osteoclast-associated inflammatory osteolytic disease.

In Silico Analysis of miR-181a and miR-155 and Their Target Genes in the Pathogenesis of Acute Lymphoblastic Leukaemia

Acute lymphoblastic leukaemia (ALL) represents 80% of acute leukaemia in children and 20% in adults. In most cases, the cause remains unknown; however, genetic predisposition is found in most patients. Clinically, a patient is diagnosed with ALL when peripheral blood smear or bone marrow aspirate is overpopulated with lymphoblasts. Although the 5-year overall survival rate exceeds 90% using available treatments, the life-threatening effects still affect some patients [1]. Therefore, further improvement in clinical outcomes and reduction of adverse effects require novel therapeutic approaches such as microRNAs (miRNAs) biomarkers. In addition, miRNAs have demonstrated distinct expression profiles in classifying the ALL subtypes and involved in various cancers [2].&#x0D; &#x0D; Previously, miR-181a and miR-155 have been discussed, either acting as oncogenic or tumour suppressive miRNAs in carcinogenesis. The study aims to investigate the role of miR-181a and miR-155 and their predicted target genes in the pathogenesis of ALL. Hence, in silico analysis was conducted using miRDB 6.0 software to identify the predicted target genes and GeneCodis 4.0 software to identify signalling pathways regulated by miR-181a and miR-155. As presented in Table 1, miR-181a was found to be downregulated whereas miR-155 was significantly upregulated in ALL groups as compared to control groups [3].&#x0D; Analysis of target expression was conducted to identify predicted target genes in ALL cell line, DND-41. In this study, the predicted target genes are regulated by miR-181a and miR-155 (with target score ≥ 80 and target expression ≥ 20) revealed 57 genes and 29 genes, respectively. The most significant genes regulated by miR-181a and miR- 155 were DUSP6 and H3F3A, respectively. DUSP6 is a regulator for hyperactivation of the extracellular signal- regulated kinase (ERK) in relapsed pre-B ALL patients. Thus, this reaction caused lesions in the RAS pathway and oncogenic tyrosine kinases (e.g., BCR-ABL1).&#x0D; &#x0D; Additionally, a complete transformation of pre-B ALL clones was done by BCR-ABL1 and correlated with the activity of other MAPKs such as MAPK14 and MAP2K1. Therefore, ERK was identified as a negative feedback regulator of the RAS-ERK pathway [4].&#x0D; &#x0D; H3F3A was reported to be involved in the pathogenesis of paediatric leukaemia caused by mutated genes that encoded proteins during epigenetic regulation. The mutation in H3F3A led to the inability of this residue to undergo periodic regulatory post-translational modifications and blocked trimethylation of all H3 during T-ALL pathogenesis. Specifically, the recurrent T-ALL patients found the lysine-to-arginine mutations at H3K27 and H3K36. Hence, the reduced expression of H3 proteins was associated with unfavourable prognosis [5].&#x0D; &#x0D; The functional enrichment analysis of KEGG pathway was conducted by using GeneCodis 4.0 software. The most significant pathway targeted by miR-181a and miR-155 was p53 signalling pathway and MAPK pathway, respectively.&#x0D; &#x0D; SESN3 was mainly responsive to p53 protein by inducing its expression upon oxidative stress and strictly associated with the antioxidant response during p53 signalling pathway. Hence, SESN3 could be a potential therapeutic drug for anticancer therapy, such as decreased mTORC1 mechanism in leukaemia patients [6]. Besides that, FOS was disrupted the MAPK pathway components, specifically MEK1 and MEK2 which could increase sensitivity to chemotherapy in relapsed ALL patients. These components were involved in ERK phosphorylation that critically drives chemoresistance during MAPK/ERK signalling pathway [7].&#x0D; &#x0D; In conclusion, differentially expressed miRNAs have promising roles and can be used as effective biomarkers for diagnostic, prognostic, predictive and therapeutic effects in ALL patients.

Ningmitai capsules have anti-inflammatory and pain-relieving effects in the chronic prostatitis/chronic pelvic pain syndrome mouse model through systemic immunity.

Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) seriously affects the physical and mental health of approximately 90% of males. Due to its complex and unclear etiology, the treatment methods that are currently available for chronic prostatitis/chronic pelvic pain syndrome are controversial, and their efficacy is unsatisfactory. At present, most researchers believe that this kind of prostatitis is caused by autoimmune inflammation. Chinese herbs, which are the essence of traditional Chinese medicine (TCM), are emerging treatment options for inflammation and immune diseases. In this experiment, we investigated the effect of Ningmitai capsules (a kind of traditional Chinese medicine widely used to treat lower urinary tract inflammation and pain in males) on chronic prostatitis/chronic pelvic pain syndrome in a non-obese diabetes-experimental autoimmune prostatitis (NOD-EAP) mouse model. First, by using bioinformatics analysis of data from the Encyclopedia of Traditional Chinese Medicine (ETCM) database, we found that quercetin, which is one of the main components of Ningmitai capsules, could reduce the secretion of CCL2 by inhibiting the MAPK pathway. In animal experiments, it was found that after Ningmitai treatment, the inflammation in mouse prostates was alleviated, the expression of CCL2, which is related to pain, and MAPK pathway components were downregulated, and the activation of the inflammatory NF–κB and STAT3 pathways was reduced. Pelvic pain and inflammation were relieved in mice with EAP. Due to the presence of the blood–prostate barrier, the drug may not completely reach the prostate directly and take effect locally. However, we found that after Ningmitai treatment, the proportions of proinflammatory CD11b+Ly6Chigh immune cells in the spleen, bloodstream (systemic immunity), and prostate (local immunity) were reduced. The infiltration of CD11b+ immune cells into the spleen and prostate was decreased. These findings suggested that Ningmitai can treat chronic prostatitis/chronic pelvic pain syndrome by affecting systemic and local immunities through the CCL2–MAPK pathway.

Disentangling ERBB Signaling in Breast Cancer Subtypes-A Model-Based Analysis.

Simple SummaryBreast cancer subtypes are characterized by the expression and activity of estrogen-, progesterone- and HER2-receptors and differ by the treatment as well as patient prognosis. Tumors of the HER2-subtype overexpress this receptor and are successfully targeted with anti-HER2 therapies. We wanted to know if the HER2-receptor and the downstream signaling network act similarly also in the other subtypes and if this network could potentially be a therapeutic target beyond the HER2-positive subtype. To this end, we quantitatively assessed the wiring of signaling events in the individual subtypes to unravel the characteristics of HER-signaling. Our data along with a model-based analysis suggest that major parts of the intracellular signal transduction network are unchanged between the different breast cancer subtypes and that the clinical differences mostly come from the different levels at which these receptors are present in tumor cells as well as from the particular mutations that are present in individual tumors.Targeted therapies have shown striking success in the treatment of cancer over the last years. However, their specific effects on an individual tumor appear to be varying and difficult to predict. Using an integrative modeling approach that combines mechanistic and regression modeling, we gained insights into the response mechanisms of breast cancer cells due to different ligand–drug combinations. The multi-pathway model, capturing ERBB receptor signaling as well as downstream MAPK and PI3K pathways was calibrated on time-resolved data of the luminal breast cancer cell lines MCF7 and T47D across an array of four ligands and five drugs. The same model was then successfully applied to triple negative and HER2-positive breast cancer cell lines, requiring adjustments mostly for the respective receptor compositions within these cell lines. The additional relevance of cell-line-specific mutations in the MAPK and PI3K pathway components was identified via L1 regularization, where the impact of these mutations on pathway activation was uncovered. Finally, we predicted and experimentally validated the proliferation response of cells to drug co-treatments. We developed a unified mathematical model that can describe the ERBB receptor and downstream signaling in response to therapeutic drugs targeting this clinically relevant signaling network in cell line that represent three major subtypes of breast cancer. Our data and model suggest that alterations in this network could render anti-HER therapies relevant beyond the HER2-positive subtype.

Advances in Biomarker-Driven Targeted Therapies in Thyroid Cancer.

Simple SummaryThis article reviews current treatment practices for thyroid cancer with a focus on novel targeted molecular therapy. Rapidly expanding knowledge of the molecular biology of these cancers coupled with the increased availability of genetic testing has led to exciting paradigm shifts in treatment strategies for these tumor types. We aim to provide up-to-date information on these state-of-the-art therapies as a guide for clinicians who specialize in the treatments of thyroid cancer.Thyroid cancer is the most common type of endocrine malignancy comprising 2–3% of all cancers, with a constant rise in the incidence rate. The standard first-line treatments for thyroid cancer include surgery and radioactive iodine ablation, and a majority of patients show a good response to these therapies. Despite a better response and outcome, approximately twenty percent of patients develop disease recurrence and distant metastasis. With improved knowledge of molecular dysregulation and biological characteristics of thyroid cancer, the development of new treatment strategies comprising novel targets has accelerated. Biomarker-driven targeted therapies have now emerged as a trend for personalized treatments in patients with advanced cancers, and several multiple receptor kinase inhibitors have entered clinical trials (phase I/II/III) to evaluate their safety and efficacy. Most extensively investigated and clinically approved targeted therapies in thyroid cancer include the tyrosine receptor kinase inhibitors that target antiangiogenic markers, BRAF mutation, PI3K/AKT, and MAPK pathway components. In this review, we focus on the current advances in targeted mono- and combination therapies for various types of thyroid cancer.

Methylglyoxal Drives a Distinct, Nonclassical Macrophage Activation Status.

Metabolic complications in diabetic patients are driven by a combination of increased levels of nutrients and the presence of a proinflammatory environment. Methylglyoxal (MG) is a toxic byproduct of catabolism and has been strongly associated with the development of such complications. Macrophages are key mediators of inflammatory processes and their contribution to the development of metabolic complications has been demonstrated. However, a direct link between reactive metabolites and macrophage activation has not been demonstrated yet. Here, we show that acute MG treatment activated components of the p38 MAPK pathway and enhanced glycolysis in primary murine macrophages. MG induced a distinct gene expression profile sharing similarities with classically activated proinflammatory macrophages as well as metabolically activated macrophages usually found in obese patients. Transcriptomic analysis revealed a set of 15 surface markers specifically upregulated in MG-treated macrophages, thereby establishing a new set of targets for diagnostic or therapeutic purposes under high MG conditions, including diabetes. Overall, our study defines a new polarization state of macrophages that may specifically link aberrant macrophage activation to reactive metabolites in diabetes.

Many Distinct Ways Lead to Drug Resistance in BRAF- and NRAS-Mutated Melanomas.

Advanced melanoma is a relentless tumor with a high metastatic potential. The combat of melanoma by using the targeted therapy is impeded because several major driver mutations fuel its growth (predominantly BRAF and NRAS). Both these mutated oncogenes strongly activate the MAPK (MEK/ERK) pathway. Therefore, specific inhibitors of these oncoproteins or MAPK pathway components or their combination have been used for tumor eradication. After a good initial response, resistant cells develop almost universally and need the drug for further expansion. Multiple mechanisms, sometimes very distant from the MAPK pathway, are responsible for the development of resistance. Here, we review many of the mechanisms causing resistance and leading to the dismal final outcome of mutated BRAF and NRAS therapy. Very heterogeneous events lead to drug resistance. Due to this, each individual mechanism would be in fact needed to be determined for a personalized therapy to treat patients more efficiently and causally according to molecular findings. This procedure is practically impossible in the clinic. Other approaches are therefore needed, such as combined treatment with more drugs simultaneously from the beginning of the therapy. This could eradicate tumor cells more rapidly and greatly diminish the possibility of emerging mechanisms that allow the evolution of drug resistance.

Differentially expressed genes involved in immune pathways from yellowhead catfish (Tachysurus fulvidraco) after poly (I:C) challenge

Yellowhead catfish (Tachysurus fulvidraco) is an important aquaculture fish species in China with a high market value. Infectious diseases pose serious threats in farmed fish species, and although vaccines can prevent certain infections, they rely on potent adjuvants. In this study, we analyzed the transcriptomic profiles of spleens from poly (I:C)-treated T. fulvidraco. We obtained 46,362,922 reads corresponding to 490,926 transcripts and 318,059 genes. Gene annotation using different databases and subsequent differential gene expression analyses led to the identification of 5587 differentially expressed genes (DEGs), of which 2473 were up-regulated and 3114 were down-regulated in poly (I:C)-treated fish. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses of DEGs revealed the significant dysregulation of immune- and cancer-related genes in the spleens of poly (I:C)-treated fish. Notably, several components of JAK-STAT, MAPK, and p53 signaling pathways were significantly dysregulated in response to poly (I:C) treatment. Quantitative real-time PCR (qRT-PCR) analysis of 11 randomly selected immune response genes confirmed the reliability of our findings. In conclusion, our findings provide novel insight into the immune responses of T. fulvidraco and suggest that poly (I:C) may represent a promising adjuvant of fish vaccines.

The GUL-1 Protein Binds Multiple RNAs Involved in Cell Wall Remodeling and Affects the MAK-1 Pathway in Neurospora crassa.

The Neurospora crassa GUL-1 is part of the COT-1 pathway, which plays key roles in regulating polar hyphal growth and cell wall remodeling. We show that GUL-1 is a bona fide RNA-binding protein (RBP) that can associate with 828 "core" mRNA species. When cell wall integrity (CWI) is challenged, expression of over 25% of genomic RNA species are modulated (2,628 mRNAs, including the GUL-1 mRNA). GUL-1 binds mRNAs of genes related to translation, cell wall remodeling, circadian clock, endoplasmic reticulum (ER), as well as CWI and MAPK pathway components. GUL-1 interacts with over 100 different proteins, including stress-granule and P-body proteins, ER components and components of the MAPK, COT-1, and STRIPAK complexes. Several additional RBPs were also shown to physically interact with GUL-1. Under stress conditions, GUL-1 can localize to the ER and affect the CWI pathway-evident via altered phosphorylation levels of MAK-1, interaction with mak-1 transcript, and involvement in the expression level of the transcription factor adv-1. We conclude that GUL-1 functions in multiple cellular processes, including the regulation of cell wall remodeling, via a mechanism associated with the MAK-1 pathway and stress-response.

Screening of binding proteins that interact with two components of the HOG MAPK pathway by the yeast two-hybrid method in Colletotrichum siamense

In phytopathogenic fungi, the Hog1 MAPK pathway plays roles in osmoregulation, oxidation responses, fungicide sensitivity, among others. However, how fungi depend on the HOG MAPK pathway to regulate their functions is poorly understood. To further elucidate the molecular mechanisms of the HOG MAPK pathway, a yeast two-hybrid (Y2H) system was adopted to screen interacting proteins of two key components (CsPbs2 and CsHog1) of the HOG MAPK pathway in a cDNA library of Colletotrichum siamense. The results showed that 19 proteins may interact with CsPbs2, including cytochrome P450 4F5, ceramide very-long-chain fatty acid hydroxylase SCS7, the oxidative stress response two-component system protein SSK1, and other proteins. Twenty-one proteins may interact with CsHog1, including the cell wall protein PhiA, acriflavine sensitivity control protein acr-2, arachidonate 15-lipoxygenase, respiratory supercomplex factor 2-like protein, and others. Five proteins interact with both CsHog1 and CsPbs2: antigenic thaumatin-like protein, aspirochlorine biosynthesis protein N, secreted beta-glucosidase sun 1, alcohol dehydrogenase 1, and hypothetical protein GQ607_005106. Furthermore, the interaction of CsSCS7 and CsCytP450 4F5 with CsPbs2 was verified by His pull-down. qPCR revealed significantly upregulated CsPbs2, CsHog1, CsSCS7 and CsCytP450 4F5 expression in Colletotrichum treated with 50 μg/mL fludioxonil for 2 h. This research identified candidate CsHog1- and CsPbs2-interacting proteins via a Y2H system and confirmed the interactions of CsSCS7 and CsCytP450 4F5 with CsPbs2. The findings lay the foundation for further studies of HOG MAPK pathway function and regulatory mechanisms, especially regarding fungicide sensitivity.

H2O2 mediated FLIP and XIAP down-regulation involves increased ITCH expression and ERK-Akt crosstalk in imatinib resistant Chronic Myeloid Leukemia cell line K562

Regulation of anti-apoptotic protein FLICE-like inhibitory protein (FLIP) and X-linked inhibitor of apoptosis protein (XIAP) remains a crucial step in the cell fate determination and thus targeting these anti-apoptotic proteins could be a viable strategy for the treatment of cancer. However the regulation of FLIP and XIAP is not very well established till date. Here we have shown that ROS decreased XIAP and FLIP by activation of ubiquitin-proteasomal pathway in imatinib resistant K562 cells. Activation of the components of MAPK pathway, ERK and JNK, played a crucial role in XIAP and FLIP degradation because ectopic expression or knock down of ERK and JNK changed the pattern of ROS mediated down-regulation of these two proteins. We have also found that JNK and ERK differentially regulates FLIP and XIAP, respectively. Moreover, our data suggests that activated ERK decreased Akt phosphorylation and thus its binding to and stabilization of XIAP. On the other hand, JNK activation increased E3 ubiquitin ligase ITCH expression and its binding to FLIP which leads to its degradation. Thus, we have, for the first time elucidated that ROS mediated ERK-Akt crosstalk regulates XIAP. We have also shown for the first time that ROS regulates ITCH expression which controls FLIP degradation.

Insight into Cisplatin-Resistance Signaling of W1 Ovarian Cancer Cells Emerges mTOR and HSP27 as Targets for Sensitization Strategies.

The microenvironment possesses a strong impact on the tumor chemoresistance when cells bind to components of the extracellular matrix. Here we elucidate the signaling pathways of cisplatin resistance in W1 ovarian cancer cells binding to collagen type 1 (COL1) and signaling interference with constitutive cisplatin resistance in W1CR cells to discover the targets for sensitization. Proteome kinase arrays and Western blots were used to identify the signaling components, their impact on cisplatin resistance was evaluated by inhibitory or knockdown approaches. W1 cell binding to COL1 upregulates integrin-associated signals via FAK/PRAS40/mTOR, confirmed by β1-integrin (ITGB1) knockdown. mTOR appears as key for resistance, its blockade reversed COL1 effects on W1 cell resistance completely. W1CR cells compensate ITGB1-knockdown by upregulation of discoidin domain receptor 1 (DDR1) as alternative COL1 sensor. COL1 binding via DDR1 activates the MAPK pathway, of which JNK1/2 appears critical for COL1-mediated resistance. JNK1/2 inhibition inverts COL1 effects in W1CR cells, whereas intrinsic cisplatin resistance remained unaffected. Remarkably, knockdown of HSP27, another downstream MAPK pathway component overcomes intrinsic resistance completely sensitizing W1CR cells to the level of W1 cells for cisplatin cytotoxicity. Our data confirm the independent regulation of matrix-induced and intrinsic chemoresistance in W1 ovarian cancer cells and offer novel targets for sensitization.

Abstract LB-063: ARID1A mutations induce an EGFR-like gene expression signature and confer intrinsic and acquired resistance to cetuximab treatment in first line metastatic CRC

Abstract Extensive biological and clinical evidence supports the notion many CRC tumors are addicted to EGFR/KRAS/MAPK signaling. For example, mutations in KRAS, BRAF and other MAPK pathway components confer intrinsic or acquired resistance to anti-EGFR therapy. However, a significant proportion of acquired resistance cases have remained unexplained. ARID1A mutations are found in approximately 11% of CRC tumors, but a connection between ARID1A mutations and EGFR/MAPK signaling activation in CRC has not been previously suspected. By leveraging the genomic biomarker data collected from 333 patients at baseline and at progression who participated in the CALGB/SWOG 80405 trial, we found that mutations in ARID1A, a key component of SWI/SNF complex, were enriched in the cell free DNA of 6/16 of the patients whose tumors had become resistant to anti-EGFR therapy with ARID1A mutations detected at either timepoint (adj. p = 0.03, OR = 0.09, two-tailed fisher's exact test). In contrast, there was no evidence of enriched ARID1A mutations in patients treated with bevacizumab. To investigate the potential role of a broader ARID1A deficiency phenotype in resistance to cetuximab therapy, we developed an ARID1A mutant-like signature from TCGA that captures the transcriptional profile characteristic of ARID1A mutants. Using this signature to stratify CALGB patients based on gene expression data collected on tissue at diagnosis, we also found patients with an ARID1A mutant-like gene expression profile had worst outcome in patients treated with cetuximab than bevacizumab with adjustment for established clinical variables for both OS [p = 0.0002, hazard ratio (HR) 6.2, 95% confidence interval (CI) 2.4-16], and PFS [p = 0.0008, HR 4.7 (1.9 -12)], suggesting that ARID1A mutations may be also a mechanism of intrinsic resistance to anti-EGFR therapies. Gene expression analysis demonstrated that ARID1A deficiency leads to re-activation of an EGFR-like signature, suggesting reactivation of this pathway as a possible mechanism of resistance. Furthermore, CRISPR knockout of ARID1A in the cetuximab-sensitive CRC cell line NCI-H508 conferred elevated MAPK signaling relative to parental line and resistance to cetuximab in culture. Consistent with these findings, we also observed strong mutual exclusivity between ARID1A mutations and mutations in the EGFR/MAPK signaling pathway in more than 40,000 lung and colorectal cancer patients profiled in the FoundationCore® database. Strikingly, in lung cancers where EGFR mutations structural variants (SV) are more prevalent, EGFR SV was the top mutually exclusive alteration with ARID1A mutations in lung cancers. Of 5980 lung cancer patients with ARID1A and/or EGFR SVs, only 100 patients (1.7%) had both SVs. Taken together, our data suggest that ARID1A loss-of-function mutations may promote resistance to cetuximab by driving an EGFR-like transcription program in the absence of ligand-dependent activation of EGFR. Our results suggest that ARID1A defects could be potentially used as an exclusion biomarker for cetuximab treatment decisions, and they provide a rationale for exploring therapeutic MAPK inhibition in ARID1A mutant CRC patients. Citation Format: Radia Marie Johnson, Xueping Qu, Joshua Thomas, Yvonne Kschonsak, Ling-Yuh Huw, Fang-Shu Ou, Ethan Sokol, Nnamdi Ihuegbu, Oliver Zill, Omar Kabbarah, Anneleen Daemen, Richard Bourgon, Alan Venook, Federico Innocenti, Heinz-Josef Lenz, Felipe de Sousa e Melo, Carlos Bais. ARID1A mutations induce an EGFR-like gene expression signature and confer intrinsic and acquired resistance to cetuximab treatment in first line metastatic CRC [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr LB-063.

The role of vegetative cell fusions in the development and asexual reproduction of the wheat fungal pathogen Zymoseptoria tritici

BackgroundThe ability of fungal cells to undergo cell-to-cell communication and anastomosis, the process of vegetative hyphal fusion, allows them to maximize their overall fitness. Previous studies in a number of fungal species have identified the requirement of several signaling pathways for anastomosis, including the so far best characterized soft (So) gene, and the MAPK pathway components MAK-1 and MAK-2 of Neurospora crassa. Despite the observations of hyphal fusions’ involvement in pathogenicity and host adhesion, the connection between cell fusion and fungal lifestyles is still unclear. Here, we address the role of anastomosis in fungal development and asexual reproduction in Zymoseptoria tritici, the most important fungal pathogen of wheat in Europe.ResultsWe show that Z. tritici undergoes self-fusion between distinct cellular structures, and its mechanism is dependent on the initial cell density. Contrary to other fungi, cell fusion in Z. tritici only resulted in cytoplasmic mixing but not in multinucleated cell formation. The deletion of the So orthologous ZtSof1 disrupted cell-to-cell communication affecting both hyphal and germling fusion. We show that Z. tritici mutants for MAPK-encoding ZtSlt2 (orthologous to MAK-1) and ZtFus3 (orthologous to MAK-2) genes also failed to undergo anastomosis, demonstrating the functional conservation of this signaling mechanism across species. Additionally, the ΔZtSof1 mutant was severely impaired in melanization, suggesting that the So gene function is related to melanization. Finally, we demonstrated that anastomosis is dispensable for pathogenicity, but essential for the pycnidium development, and its absence abolishes the asexual reproduction of Z. tritici.ConclusionsWe demonstrate the role for ZtSof1, ZtSlt2, and ZtFus3 in cell fusions of Z. tritici. Cell fusions are essential for different aspects of the Z. tritici biology, and the ZtSof1 gene is a potential target to control septoria tritici blotch (STB) disease.

Dehydrodieugenol improved lung inflammation in an asthma model by inhibiting the STAT3/SOCS3 and MAPK pathways

BackgroundEugenol, a common phenylpropanoid derivative found in different plant species, has well-described anti-inflammatory effects associated with the development of occupational hypersensitive asthma. Dehydrodieugenol, a dimeric eugenol derivative, exhibits anti-inflammatory and antioxidant activities and can be found in the Brazilian plant species Nectandra leucantha (Lauraceae). The biological effects of dehydrodieugenol on lung inflammation remain unclear. PurposeThis study aimed to investigate the effects of eugenol and dehydrodieugenol isolated from N. leucantha in an experimental model of asthma. MethodsIn the present work, the toxic effects of eugenol and dehydrodieugenol on RAW 264.7 cells and their oxidant and inflammatory effects before lipopolysaccharide (LPS) exposure were tested. Then, male BALB/c mice were sensitized with ovalbumin through a 29-day protocol and treated with vehicle, eugenol, dehydrodieugenol or dexamethasone for eight days beginning on the 22nd day until the end of the protocol. Lung function; the inflammatory profile; and the protein expression of ERK1/2, JNK, p38, VAChT, STAT3, and SOCS3 in the lung were evaluated by immunoblotting. ResultsEugenol and dehydrodieugenol were nontoxic to cells. Both compounds inhibited NO release and the gene expression of IL-1β and IL-6 in LPS-stimulated RAW 264.7 cells. In OVA-sensitized animals, dehydrodieugenol reduced lung inflammatory cell numbers and the lung concentrations of IL-4, IL-13, IL-17, and IL-10. These anti-inflammatory effects were associated with inhibition of the JNK, p38 and ERK1/2, VAChT and STAT3/SOCS3 pathways. Moreover, treatment with dehydrodieugenol effectively attenuated airway hyperresponsiveness. Conclusion: The obtained data demonstrate, for the first time, that dehydrodieugenol was more effective than eugenol in counteracting allergic airway inflammation in mice, especially its inhibition of the JNK, p38 and ERK1/2, components of MAPK pathway. Therefore, dehydrodieugenol can be considered a prototype for the development of new and effective agents for the treatment of asthmatic patients.

Reduced replication origin licensing selectively kills KRAS-mutant colorectal cancer cells via mitotic catastrophe

To unravel vulnerabilities of KRAS-mutant CRC cells, a shRNA-based screen specifically inhibiting MAPK pathway components and targets was performed in CaCo2 cells harboring conditional oncogenic KRASG12V. The custom-designed shRNA library comprised 121 selected genes, which were previously identified to be strongly regulated in response to MEK inhibition. The screen showed that CaCo2 cells expressing KRASG12V were sensitive to the suppression of the DNA replication licensing factor minichromosome maintenance complex component 7 (MCM7), whereas KRASwt CaCo2 cells were largely resistant to MCM7 suppression. Similar results were obtained in an isogenic DLD-1 cell culture model. Knockdown of MCM7 in a KRAS-mutant background led to replication stress as indicated by increased nuclear RPA focalization. Further investigation showed a significant increase in mitotic cells after simultaneous MCM7 knockdown and KRASG12V expression. The increased percentage of mitotic cells coincided with strongly increased DNA damage in mitosis. Taken together, the accumulation of DNA damage in mitotic cells is due to replication stress that remained unresolved, which results in mitotic catastrophe and cell death. In summary, the data show a vulnerability of KRAS-mutant cells towards suppression of MCM7 and suggest that inhibiting DNA replication licensing might be a viable strategy to target KRAS-mutant cancers.

Anti-Breast Cancer Effect of 2-Dodecyl-6-Methoxycyclohexa-2,5-Diene-1,4-Dione in vivo and in vitro Through MAPK Signaling Pathway.

Background2-Dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione (DMDD) has been reported to inhibit a variety of cancer cell lines. The purpose of this study was to investigate the effects of DMDD on 4T1 breast cancer cells and the effects of DMDD on 4T1 breast cancer in mice and its molecular mechanisms.Methods4T1 breast cancer cells were treated with different concentrations of DMDD, and their proliferation, apoptosis, cell-cycle distribution, migration, and invasion were detected by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT, Acridine orange and ethidium bromide dual staining analysis (AO/EB) dual staining, flow cytometry, scratch test, and the Transwell assay. Relative quantitative real-time qPCR analysis and Western blot were applied to examine the expression levels of related genes and proteins. In animal experiments, we established a xenograft model to assess the anti-breast cancer effects of DMDD by evaluating the inhibition rate. The apoptotic activity of DMDD was evaluated by hematoxylin-eosin (HE) staining, transmission electron microscope (TEM) analysis and TdT-mediated dUTP nick end labeling (TUNEL) assays. The mRNA expression levels of MAPK pathway components were detected by relative quantitative real-time qPCR. In addition, the protein expression levels of MAPK pathway components were assessed through immunohistochemical assays and Western blotting.ResultsExperiments showed that DMDD could inhibit the proliferation, migration, invasion of 4T1 cells and induce cellular apoptosis and G1 cell cycle arrest. Moreover, DMDD down-regulated the mRNA expressions of raf1, mek1, mek2, erk1, erk2, bcl2, and up-regulated the mRNA expression of bax. DMDD reduced the protein expressions of p-raf1, p-mek, p-erk, p-p38, Bcl2, MMP2, MMP9 and increased the protein expressions of Bax and p-JNK. The results showed that DMDD can effectively reduce the tumor volume and weight of breast cancer in vivo, up-regulate the expression of IL-2, down-regulate the expression of IL-4 and IL-10, induce the apoptosis of breast cancer cells in mice, and regulate the expression of genes and proteins of the MAPK pathway.ConclusionOur study indicates that DMDD can inhibit proliferation, migration, and invasion and induces apoptosis and cell-cycle arrest of 4T1 breast cancer cells. Also, our findings indicate that DMDD induces the apoptosis of breast cancer cells and inhibits the growth in mice. Its mechanism may be related to the MAPK pathway.