Irreversible JNK1-JUN inhibition by JNK-IN-8 sensitizes pancreatic cancer to 5-FU/FOLFOX chemotherapy

A focus on c-Jun-N-terminal kinase signaling in sepsis-associated multiple organ dysfunction: Mechanisms and therapeutic strategies

Sepsis is a life-threatening condition characterized by a widespread inflammatory response to infection, inevitably leading to multiple organ dysfunctions. Extensive research, both in vivo and in vitro, has revealed key factors contributing to sepsis, such as apoptosis, inflammation, cytokine release, oxidative stress, and systemic stress. The changes observed during sepsis-induced conditions are mainly attributed to altered signal transduction pathways, which play a critical role in cell proliferation, migration, and apoptosis. C-Jun N-terminal kinases, JNKs, and serine/threonine protein kinases in the mitogen-activated super family have gained considerable interest for their contribution to cellular events under sepsis conditions. JNK1 and JNK2 are present in various tissues like the lungs, liver, and intestine, while JNK3 is found in neurons. The JNK pathway plays a crucial role in the signal transduction of cytokines related to sepsis development, notably TNF-α and IL-1β. Activated JNK leads to apoptosis, causing tissue damage and organ dysfunction. Further, JNK activation is significant in several inflammatory conditions. Pharmacologically inhibiting JNK has been shown to prevent sepsis-associated damage across multiple organs, including the lungs, liver, intestines, heart, and kidneys. Multiple signaling pathways have been implicated in sepsis, including JNK/c-Myc, Mst1-JNK, MKK4-JNK, JNK-dependent autophagy, and Sirt1/FoxO3a. The review examines the role of JNK signaling in the development of sepsis-induced multiple-organ dysfunction through specific mechanisms. It also discusses different therapeutic approaches to target JNK. This review emphasizes the potential of JNKs as targets for the development of therapeutic agents for sepsis and the associated specific organ damage.

Inhibition of JNK signaling attenuates photoreceptor ferroptosis caused by all-trans-retinal

The disruption of the visual cycle leads to the accumulation of all-trans-retinal (atRAL) in the retina, a hallmark of autosomal recessive Stargardt disease (STGD1) and dry age-related macular degeneration (AMD), both of which cause retinal degeneration. Although our previous studies have shown that atRAL induces ferroptosis and activates c-Jun N-terminal kinase (JNK) signaling in the retina, the relationship between JNK signaling and ferroptosis in atRAL-mediated photoreceptor damage remains unclear. Here, we reported that JNK activation by atRAL drove photoreceptor ferroptosis through ferritinophagy. In photoreceptor cells loaded with atRAL, activated JNK phosphorylated c-Jun, which facilitated its nuclear translocation and promoted the expression of the nuclear receptor coactivator 4 (NCOA4). Elevated NCOA4 induced ferritin degradation via lysosomal processing, a process known as ferritinophagy, thereby releasing a large amount of labile iron. Iron overload led to the generation of reactive oxygen species (ROS) and lipid peroxidation, ultimately culminating in ferroptosis. Treatment with the JNK inhibitor JNK-IN-8, as well as the knockout of Jnk1 and Jnk2 genes, significantly rescued atRAL-loaded photoreceptor cells from ferritinophagy-induced ferroptosis. Abca4-/-Rdh8-/- mice, which exhibit atRAL accumulation in the retina following light exposure, are commonly used to study the pathological processes of STGD1 and dry AMD. In these mice, light exposure activated the JNK/c-Jun/NCOA4 axis, resulting in ferritinophagy in the neural retina. Importantly, intraperitoneal administration of JNK-IN-8 significantly rescued retinal function and photoreceptors from ferritinophagy-induced ferroptosis and effectively mitigated retinal degeneration in light-exposed Abca4-/-Rdh8-/- mice. This study underscores the critical role of the JNK/c-Jun/NCOA4 axis in mediating atRAL-induced ferritinophagy, which drives ferroptosis and retinal atrophy, suggesting that targeting this pathway may offer a potential therapeutic approach for STGD1 and dry AMD.

Beyond endocrine resistance: estrogen receptor (ESR1) activating mutations mediate chemotherapy resistance through the JNK/c-Jun MDR1 pathway in breast cancer

PURPOSE

All patients with metastatic breast cancer (MBC) expressing estrogen receptor-α (ESR1) will eventually develop resistance to endocrine therapies. In up to 40% of patients, this resistance is caused by activating mutations in the ligand-binding domain (LBD) of ESR1. Accumulating clinical evidence indicate adverse outcomes for these patients, beyond that expected by resistance to endocrine therapy. Here we aimed to study the role of ESR1 mutations in conferring chemoresistance in BC cells.

METHODS

MCF-7 cells harboring Y537S and D538G ESR1 mutations (mut-ER) were employed to study the response to chemotherapy drugs, paclitaxel and doxorubicin, using viability and apoptotic assay in vitro, and tumor growth in vivo. JNK/c-Jun/MDR1 pathway was studied using qRT-PCR, western-blot, gene-reporter and ChIP assays. MDR1 expression was analyzed in clinical samples using IHC.

RESULTS

 Cell harboring ESR1 mutations displayed relative chemoresistance compared to WT-ER, evidenced by higher viability and reduced apoptosis as well as resistance to paclitaxel in vivo. To elucidate the underlying mechanism, MDR1 expression was examined and elevated levels were observed in mut-ER cells, and in clinical BC samples. MDR1 is regulated by the c-Jun pathway, and we showed high correlation between these two genes in BC using TCGA databases. Accordingly, we detected higher JNK/c-Jun expression and activity in ESR1-mutated cells, as well as increased occupancy of c-Jun in MDR1 promoter. Importantly, JNK inhibition decreased MDR1 expression and restored sensitivity to chemotherapy.

CONCLUSIONS

Taken together, these data indicate that ESR1 mutations confer chemoresistance through activation of the JNK/MDR1 axis. These finding suggest a novel treatment option for BC tumors expressing ESR1 mutations.

Cell-specific models reveal conformation-specific RAF inhibitor combinations that synergistically inhibit ERK signaling in pancreatic cancer cells

Pancreatic ductal adenocarcinoma (PDAC) presents significant challenges for targeted clinical interventions due to prevalent KRAS mutations, rendering PDAC resistant to RAF and MEK inhibitors (RAFi and MEKi). In addition, responses to targeted therapies vary between patients. Here, we explored the differential sensitivities of PDAC cell lines to RAFi and MEKi and developed an isogenic pair comprising the most sensitive and resistant PDAC cells. To simulate patient- or tumor-specific variations, we constructed cell-line-specific mechanistic models based on protein expression profiling and differential properties of KRAS mutants. These models predicted synergy between two RAFi with different conformation specificity (type I½ and type II RAFi) in inhibiting phospho-ERK (ppERK) and reducing PDAC cell viability. This synergy was experimentally validated across all four studied PDAC cell lines. Our findings underscore the need for combination approaches to inhibit the ERK pathway in PDAC.

Kinome state is predictive of cell viability in pancreatic cancer tumor and cancer-associated fibroblast cell lines

Numerous aspects of cellular signaling are regulated by the kinome-the network of over 500 protein kinases that guides and modulates information transfer throughout the cell. The key role played by both individual kinases and assemblies of kinases organized into functional subnetworks leads to kinome dysregulation driving many diseases, particularly cancer. In the case of pancreatic ductal adenocarcinoma (PDAC), a variety of kinases and associated signaling pathways have been identified for their key role in the establishment of disease as well as its progression. However, the identification of additional relevant therapeutic targets has been slow and is further confounded by interactions between the tumor and the surrounding tumor microenvironment. In this work, we attempt to link the state of the human kinome, or kinotype, with cell viability in treated, patient-derived PDAC tumor and cancer-associated fibroblast cell lines. We applied classification models to independent kinome perturbation and kinase inhibitor cell screen data, and found that the inferred kinotype of a cell has a significant and predictive relationship with cell viability. We further find that models are able to identify a set of kinases whose behavior in response to perturbation drive the majority of viability responses in these cell lines, including the understudied kinases CSNK2A1/3, CAMKK2, and PIP4K2C. We next utilized these models to predict the response of new, clinical kinase inhibitors that were not present in the initial dataset for model devlopment and conducted a validation screen that confirmed the accuracy of the models. These results suggest that characterizing the perturbed state of the human protein kinome provides significant opportunity for better understanding of signaling behavior and downstream cell phenotypes, as well as providing insight into the broader design of potential therapeutic strategies for PDAC.

A Histone Methylation-MAPK Signaling Axis Drives Durable Epithelial-Mesenchymal Transition in Hypoxic Pancreatic Cancer

The tumor microenvironment in pancreatic ductal adenocarcinoma (PDAC) plays a key role in tumor progression and response to therapy. The dense PDAC stroma causes hypovascularity, which leads to hypoxia. Here, we showed that hypoxia drives long-lasting epithelial-mesenchymal transition (EMT) in PDAC primarily through a positive-feedback histone methylation-MAPK signaling axis. Transformed cells preferentially underwent EMT in hypoxic tumor regions in multiple model systems. Hypoxia drove a cell autonomous EMT in PDAC cells, which, unlike EMT in response to growth factors, could last for weeks. Furthermore, hypoxia reduced histone demethylase KDM2A activity, suppressed PP2 family phosphatase expression, and activated MAPKs to post-translationally stabilize histone methyltransferase NSD2, leading to an H3K36me2-dependent EMT in which hypoxia-inducible factors played only a supporting role. Hypoxia-driven EMT could be antagonized in vivo by combinations of MAPK inhibitors. Collectively, these results suggest that hypoxia promotes durable EMT in PDAC by inducing a histone methylation-MAPK axis that can be effectively targeted with multidrug therapies, providing a potential strategy for overcoming chemoresistance.

SIGNIFICANCE

Integrated regulation of histone methylation and MAPK signaling by the low-oxygen environment of pancreatic cancer drives long-lasting EMT that promotes chemoresistance and shortens patient survival and that can be pharmacologically inhibited. See related commentary by Wirth and Schneider, p. 1739.

Myofibroblastic cancer-associated fibroblast subtype heterogeneity in pancreatic cancer

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) has a fibrotic stroma that has both tumor-promoting and tumor-restraining properties. Different types of cancer-associated fibroblasts (CAFs) have been described. Here, we investigated whether CAFs within the same subtype exhibit heterogeneous functions.

METHODS

We evaluated the gene and protein expression differences in two myofibroblastic CAF (myCAF) lines using single-cell and bulk RNA-sequencing. We utilized proliferation and migration assays to determine the effect of different CAF lines on a tumor cell line.

RESULTS

We found that myCAF lines express an activated stroma subtype gene signature, which is associated with a shorter survival in patients. Although both myCAF lines expressed α-smooth muscle actin (α-SMA), platelet-derived growth factor-α (PDGFR-α), fibroblast-activated protein (FAP), and vimentin, we observed heterogeneity between the two lines. Similarly, despite being consistent with myCAF gene expression overall, heterogeneity within specific genes was observed. We found that these differences extended to the functional level where the two myCAF lines had different effects on the same tumor cell line. The myCAF216 line, which had slightly increased inflammatory CAF-like gene expression and higher protein expression of α-SMA, PDGFR-α, and FAP was found to restrain migration of tumor cells.

CONCLUSIONS

We found that two myCAF lines with globally similar expression characteristics had different effects on the same tumor cell line, one promoting and the other restraining migration. Our study highlights that there may be unappreciated heterogeneity within CAF subtypes. Further investigation and attention to specific genes or proteins that may drive this heterogeneity will be important.

Integrated single-dose kinome profiling data is predictive of cancer cell line sensitivity to kinase inhibitors

Protein kinase activity forms the backbone of cellular information transfer, acting both individually and as part of a broader network, the kinome. Their central role in signaling leads to kinome dysfunction being a common driver of disease, and in particular cancer, where numerous kinases have been identified as having a causal or modulating role in tumor development and progression. As a result, the development of therapies targeting kinases has rapidly grown, with over 70 kinase inhibitors approved for use in the clinic and over double this number currently in clinical trials. Understanding the relationship between kinase inhibitor treatment and their effects on downstream cellular phenotype is thus of clear importance for understanding treatment mechanisms and streamlining compound screening in therapy development. In this work, we combine two large-scale kinome profiling data sets and use them to link inhibitor-kinome interactions with cell line treatment responses (AUC/IC50). We then built computational models on this data set that achieve a high degree of prediction accuracy (R2 of 0.7 and RMSE of 0.9) and were able to identify a set of well-characterized and understudied kinases that significantly affect cell responses. We further validated these models experimentally by testing predicted effects in breast cancer cell lines and extended the model scope by performing additional validation in patient-derived pancreatic cancer cell lines. Overall, these results demonstrate that broad quantification of kinome inhibition state is highly predictive of downstream cellular phenotypes.

Proteomic Profiling of Chemotherapy Responses in FOLFOX-Resistant Colorectal Cancer Cells

Chemoresistance mechanisms of colorectal cancer remain largely elusive. We aim to compare the difference of chemotherapy responses between FOLFOX-resistant and wild-type colorectal cancer cells by proteomic profiling to suggest novel treatment targets. FOLFOX-resistant colorectal cancer cells DLD1-R and HCT116-R were developed by chronic exposure to progressive FOLFOX doses. Proteomic profiling of FOLFOX-resistant and wild-type cells under FOLFOX exposure were conducted by mass-spectrometry-based protein-analysis technology. Verification of selected KEGG pathways was conducted by Western blot. DLD1-R had significantly higher FOLFOX-chemoresistance (10.81 times) than its wild-type counterpart. A total of 309 and 90 differentially expressed proteins were identified in DLD1-R and HCT116-R, respectively. In terms of gene ontology molecular function, RNA binding and cadherin binding ranked first for DLD1 and HCT116 groups, respectively. For gene set enrichment analysis, ribosome pathway and DNA replication were significantly up-regulated and down-regulated in DLD1-R, respectively. The most significantly up-regulated pathway in HCT116-R was regulation of the actin cytoskeleton. Up-regulations in the ribosome pathway (DLD1-R) and actin cytoskeleton (HCT116-R) were verified by Western blot. There were several significantly altered signaling pathways in FOLFOX-resistant colorectal cancer cells under FOLFOX with notable up-regulations in the ribosomal process and actin cytoskeleton.

Silencing circPalm2 inhibits sepsis-induced acute lung injury by sponging miR-376b-3p and targeting MAP3K1

The apoptosis and inflammation of pulmonary epithelial cells are important pathogenic factors of sepsis-induced acute lung injury (ALI). Upregulation of circPalm2 (circ_0001212) expression levels has been previously detected in the lung tissue of ALI rats. Herein, the biological significance and detailed mechanism of circPalm2 in ALI pathogenesis were investigated. In vivo models of sepsis-induced ALI were established by treating C57BL/6 mice with cecal ligation and puncture (CLP) surgery. Murine pulmonary epithelial cells (MLE-12 cells) were stimulated with lipopolysaccharide (LPS) to establish in vitro septic ALI models. MLE-12 cell viability and apoptosis were evaluated by CCK-8 assay and flow cytometry analysis, respectively. The pathological alterations of the lung tissue were analysed based on hematoxylin-eosin (H&E) staining. Cell apoptosis in the lung tissue samples was examined by TUNEL staining assay. LPS administration suppressed the viability and accelerated the inflammation and apoptotic behaviours of MLE-12 cells. CircPalm2 displayed high expression in LPS-stimulated MLE-12 cells and possessed circular characteristics. The silencing of circPalm2 impeded apoptosis and inflammation in LPS-stimulated MLE-12 cells. Mechanistically, circPalm2 bound with miR-376b-3p, which targeted MAP3K1. In rescue assays, MAP3K1 enhancement reversed the repressive effects of circPalm2 depletion on LPS-triggered inflammatory injury and MLE-12 cell apoptosis. Furthermore, the lung tissue collected from CLP model mice displayed low miR-376b-3p expression and high levels of circPalm2 and MAP3K1. CircPalm2 positively regulated MAP3K1 expression by downregulating miR-376b-3p in murine lung tissues. Importantly, circPalm2 knockdown attenuated CLP-induced inflammation, apoptosis, and pathological alterations in lung tissues collected from mice. Silenced circPalm2 inhibits LPS-induced pulmonary epithelial cell dysfunction and mitigates abnormalities in lung tissues collected from CLP-stimulated mice via the miR-376b-3p/MAP3K1 axis in septic ALI.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43188-022-00169-7.

Interplay between MAP kinases and tumor microenvironment: Opportunity for immunotherapy in pancreatic cancer

Pancreatic Ductal Adenocarcinoma (PDAC), commonly called pancreatic cancer, is aggressive cancer usually detected at a late stage, limiting treatment options with modest clinical responses. It is projected that by 2030, PDAC will be the second most common cause of cancer-related mortality in the United States. Drug resistance in PDAC is common and significantly affects patients' overall survival (OS). Oncogenic KRAS mutations are nearly uniform in PDAC, affecting over 90% of patients. However, effective drugs directed to target prevalent KRAS mutants in pancreatic cancer are not in clinical practice. Accordingly, efforts are continued on identifying alternative druggable target(s) or approaches to improve patient outcomes with PDAC. In most PDAC cases, the KRAS mutations turn-on the RAF-MEK-MAPK pathways, leading to pancreatic tumorigenesis. The MAPK signaling cascade (MAP4K→MAP3K→MAP2K→MAPK) plays a central role in the pancreatic cancer tumor microenvironment (TME) and chemotherapy resistance. The immunosuppressive pancreatic cancer TME is another unfavorable factor affecting the therapeutic efficacy of chemotherapy and immunotherapy. The immune checkpoint proteins (ICPs), including CTLA-4, PD-1, PD-L1, and PD-L2, are critical players in T cell dysfunction and pancreatic tumor cell growth. Here, we review the activation of MAPKs, a molecular trait of KRAS mutations and their impact on pancreatic cancer TME, chemoresistance, and expression of ICPs that could influence the clinical outcomes in PDAC patients. Therefore, understanding the interplay between MAPK pathways and TME could help to design rational therapy combining immunotherapy and MAPK inhibitors for pancreatic cancer treatment.

Non-kinase targeting of oncogenic c-Jun N-terminal kinase (JNK) signaling: the future of clinically viable cancer treatments

c-Jun N-terminal Kinases (JNKs) have been identified as key disease drivers in a number of pathophysiological settings and central oncogenic signaling nodes in various cancers. Their roles in driving primary tumor growth, positively regulating cancer stem cell populations, promoting invasion and facilitating metastatic outgrowth have led JNKs to be considered attractive targets for anti-cancer therapies. However, the homeostatic, apoptotic and tumor-suppressive activities of JNK proteins limit the use of direct JNK inhibitors in a clinical setting. In this review, we will provide an overview of the different JNK targeting strategies developed to date, which include various ATP-competitive, non-kinase and substrate-competitive inhibitors. We aim to summarize their distinct mechanisms of action, review some of the insights they have provided regarding JNK-targeting in cancer, and outline the limitations as well as challenges of all strategies that target JNKs directly. Furthermore, we will highlight alternate drug targets within JNK signaling complexes, including recently identified scaffold proteins, and discuss how these findings may open up novel therapeutic options for targeting discrete oncogenic JNK signaling complexes in specific cancer settings.

JNK inhibitor IX restrains pancreatic cancer through p53 and p21

Novel treatment options for pancreatic cancer are desperately needed. De-regulated kinases can be regularly detected in pancreatic cancer. Multiple pathway inhibitors were developed to exploit these features, among them selective inhibitors of the c-Jun N-terminal kinase isoforms 1 and 2 (JNK1 and 2). We evaluated the effectiveness of four different JNK inhibitors on pancreatic cancer cell lines. Cell mobility and migration were evaluated in scratch assay and Boyden chamber assay. Mechanism of cell death was analyzed via apoptosis assays in FACS and immunoblotting as well as cell cycle analysis via FACS, and qPCR. JNK2 knockout cells were generated using siRNA transfection. Among the inhibitors, JNK inhibitor IX (JNK-in-IX), designed as specific inhibitor against JNK2 was proven highly effective in inhibiting cell growth, mobility and migration. We were able to show that JNK-in-IX caused DNA damage resulting in G2 arrest mediated through p53 and p21. Interestingly, JNK-in-IX acted independently of its primary target JNK2. In summary, JNK-in-IX was shown highly effective in pancreatic cancer. This study underlines the need for modeling systems in testing therapeutic options as JNK2 was previously not indicated as a potential target.

Curcumin Derivative C66 Suppresses Pancreatic Cancer Progression through the Inhibition of JNK-Mediated Inflammation

Pancreatic adenocarcinoma is by far the deadliest type of cancer. Inflammation is one of the important risk factors in tumor development. However, it is not yet clear whether deterioration in pancreatic cancer patients is related to inflammation, as well as the underlying mechanism. In addition, JNK is abnormally activated in pancreatic cancer cells and the JNK inhibitor C66 reduces the inflammatory microenvironment in the tumor. Therefore, the aim of this study was to evaluate the role of C66 in the proliferation and migration of pancreatic cancer. Our results showed that various inflammatory cytokines, such as IL-1β, IL-6, IL-8, and IL-15, were more expressed in pancreatic cancer than in the matching normal tissue. Furthermore, C66, a curcumin analogue with good anti-inflammatory activity, inhibited the proliferation and migration of pancreatic cancer cells in a dose-dependent manner, and effectively inhibited the expression of the above inflammatory factors. Our previous research demonstrated that C66 prevents the inflammatory response by targeting JNK. Therefore, in this study, JNK activity in pancreatic cancer cells was investigated, revealing that JNK was highly activated, and the treatment with C66 inhibited the phosphorylation of JNK. Next, shJNK was used to knockdown JNK expression in pancreatic cancer cells to further confirm the role of JNK in the proliferation and migration of this tumor, as well as in the inflammatory tumor microenvironment (TME). The results demonstrated that JNK knockdown could significantly inhibit the proliferation and migration of pancreatic cancer. Moreover, the low JNK expression in pancreatic cancer cells significantly inhibited the expression of various inflammatory factors. These results indicated that C66 inhibited the progression of pancreatic cancer through the inhibition of JNK-mediated inflammation.

Exploration of the System-Level Mechanisms of the Herbal Drug FDY003 for Pancreatic Cancer Treatment: A Network Pharmacological Investigation

Pancreatic cancer (PC) is the most lethal cancer with the lowest survival rate globally. Although the prescription of herbal drugs against PC is gaining increasing attention, their polypharmacological therapeutic mechanisms are yet to be fully understood. Based on network pharmacology, we explored the anti-PC properties and system-level mechanisms of the herbal drug FDY003. FDY003 decreased the viability of human PC cells and strengthened their chemosensitivity. Network pharmacological analysis of FDY003 indicated the presence of 16 active phytochemical components and 123 PC-related pharmacological targets. Functional enrichment analysis revealed that the PC-related targets of FDY003 participate in the regulation of cell growth and proliferation, cell cycle process, cell survival, and cell death. In addition, FDY003 was shown to target diverse key pathways associated with PC pathophysiology, namely, the PIK3-Akt, MAPK, FoxO, focal adhesion, TNF, p53, HIF-1, and Ras pathways. Our network pharmacological findings advance the mechanistic understanding of the anti-PC properties of FDY003 from a system perspective.

Assessment of drug-drug interactions of CC-90001, a potent and selective inhibitor of c-Jun N-terminal kinase

CC-90001 is predominantly metabolised via glucuronidation, while oxidative metabolism is a minor pathway in human hepatocytes and liver microsomes. In vitro, CC-90001 glucuronidation was catalysed by UGT1A9, UGT1A4, and UGT1A1, while oxidative metabolism was primarily mediated by CYP3A4/5 with minor contributions from CYP1A2, CYP2C9, CYP2B6, and CYP2D6.CC-90001 in vitro inhibits CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C19, and CYP3A4 ≤ 55% at 100 μM, and the inhibition was negligible at ≤30 μM. CC-90001 is not a time-dependent CYP inhibitor.In human hepatocytes CC-90001 is an inducer of CYP2B6 and CYP3A, with mRNA levels increased 34.4% to 52.8% relative to positive controls.In vitro CC-90001 is a substrate of P-gp, and an inhibitor of P-gp, BCRP, OAT3, OATP1B1, OATP1B3, OCT2, MATE1, and MATE2k with IC₅₀ values of 30.3, 25.8, 17.7, 0.417, 19.9, 0.605, 4.17, and 20 μM, respectively.A clinical study demonstrated that CC-90001 has no or little impact on the exposure of warfarin (CYP2C9), omeprazole (CYP2C19), midazolam (CYP3A) or metformin (OCT2, MATE1/2k). CC-90001 co-administration increases the AUC_t and C_max 176% and 339% for rosuvastatin (BCRP/OATP1B1/3), 116% and 171% for digoxin (P-gp), and 266% and 321% for nintedanib (CYP3A & P-gp), respectively.In conclusion, CC-90001 in unlikely to be a victim or perpetrator of clinically relevant interactions involving CYPs or UGTs. Weak to moderate interactions are expected in clinic with substrates of P-gp and OATP1B1 due to CC-90001 inhibition of these transporters.

TNF-α-producing macrophages determine subtype identity and prognosis via AP1 enhancer reprogramming in pancreatic cancer

Large-scale genomic profiling of pancreatic cancer (PDAC) has revealed two distinct subtypes: 'classical' and 'basal-like'. Their variable coexistence within the stromal immune microenvironment is linked to differential prognosis; however, the extent to which these neoplastic subtypes shape the stromal immune landscape and impact clinical outcome remains unclear. By combining preclinical models, patient-derived xenografts, as well as FACS-sorted PDAC patient biopsies, we show that the basal-like neoplastic state is sustained via BRD4-mediated cJUN/AP1 expression, which induces CCL2 to recruit tumor necrosis factor (TNF)-α-secreting macrophages. TNF-α+ macrophages force classical neoplastic cells into an aggressive phenotypic state via lineage reprogramming. Integration of ATAC-, ChIP- and RNA-seq data revealed distinct JUNB/AP1 (classical) and cJUN/AP1 (basal-like)-driven regulation of PDAC subtype identity. Pharmacological inhibition of BRD4 led to suppression of the BRD4-cJUN-CCL2-TNF-α axis, restoration of classical subtype identity and a favorable prognosis. Hence, patient-tailored therapy for a cJUNhigh/TNF-αhigh subtype is paramount in overcoming highly inflamed and aggressive PDAC states.

Stress-activated kinases as therapeutic targets in pancreatic cancer

Pancreatic cancer is a dismal disease with high incidence and poor survival rates. With the aim to improve overall survival of pancreatic cancer patients, new therapeutic approaches are urgently needed. Protein kinases are key regulatory players in basically all stages of development, maintaining physiologic functions but also being involved in pathogenic processes. c-Jun N-terminal kinases (JNK) and p38 kinases, representatives of the mitogen-activated protein kinases, as well as the casein kinase 1 (CK1) family of protein kinases are important mediators of adequate response to cellular stress following inflammatory and metabolic stressors, DNA damage, and others. In their physiologic roles, they are responsible for the regulation of cell cycle progression, cell proliferation and differentiation, and apoptosis. Dysregulation of the underlying pathways consequently has been identified in various cancer types, including pancreatic cancer. Pharmacological targeting of those pathways has been the field of interest for several years. While success in earlier studies was limited due to lacking specificity and off-target effects, more recent improvements in small molecule inhibitor design against stress-activated protein kinases and their use in combination therapies have shown promising in vitro results. Consequently, targeting of JNK, p38, and CK1 protein kinase family members may actually be of particular interest in the field of precision medicine in patients with highly deregulated kinase pathways related to these kinases. However, further studies are warranted, especially involving in vivo investigation and clinical trials, in order to advance inhibition of stress-activated kinases to the field of translational medicine.

Irreversible JNK blockade overcomes PD-L1-mediated resistance to chemotherapy in colorectal cancer

Colorectal cancer (CRC) cells have low or absent tumor cell PD-L1 expression that we previously demonstrated can confer chemotherapy resistance. Here, we demonstrate that PD-L1 depletion enhances JNK activity resulting in increased Bim^Thr116 phosphorylation and its sequestration by MCL-1 and BCL-2. Activated JNK signaling in PD-L1-depeted cells was due to reduced mRNA stability of the CYLD deubiquitinase. PD-L1 was found to compete with the ribonuclease EXOSC10 for binding to CYLD mRNA. Thus, loss of PD-L1 promoted binding and degradation of CYLD mRNA by EXOSC10 which enhanced JNK activity. An irreversible JNK inhibitor (JNK-IN-8) reduced Bim^Thr116 phosphorylation and unsequestered Bim from MCL-1 and BCL-2 to promote apoptosis. In cells lacking PD-L1, treatment with JNK-IN-8, an MCL-1 antagonist (AZD5991), or their combination promoted apoptosis and reduced long-term clonogenic survival by anticancer drugs. Similar effects of the JNK inhibitor on cell viability were observed in CRC organoids with suppression of PD-L1. These data indicate that JNK inhibition may represent a promising strategy to overcome drug resistance in CRC cells with low or absent PD-L1 expression.

Modeling pancreatic cancer in mice for experimental therapeutics

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy that is characterized by early metastasis, low resectability, high recurrence, and therapy resistance. The experimental mouse models have played a central role in understanding the pathobiology of PDAC and in the preclinical evaluation of various therapeutic modalities. Different mouse models with targetable pathological hallmarks have been developed and employed to address the unique challenges associated with PDAC progression, metastasis, and stromal heterogeneity. Over the years, mouse models have evolved from simple cell line-based heterotopic and orthotopic xenografts in immunocompromised mice to more complex and realistic genetically engineered mouse models (GEMMs) involving multi-gene manipulations. The GEMMs, mostly driven by KRAS mutation(s), have been widely accepted for therapeutic optimization due to their high penetrance and ability to recapitulate the histological, molecular, and pathological hallmarks of human PDAC, including comparable precursor lesions, extensive metastasis, desmoplasia, perineural invasion, and immunosuppressive tumor microenvironment. Advanced GEMMs modified to express fluorescent proteins have allowed cell lineage tracing to provide novel insights and a new understanding about the origin and contribution of various cell types in PDAC pathobiology. The syngeneic mouse models, GEMMs, and target-specific transgenic mice have been extensively used to evaluate immunotherapies and study therapy-induced immune modulation in PDAC yielding meaningful results to guide various clinical trials. The emerging mouse models for parabiosis, hepatic metastasis, cachexia, and image-guided implantation, are increasingly appreciated for their high translational significance. In this article, we describe the contribution of various experimental mouse models to the current understanding of PDAC pathobiology and their utility in evaluating and optimizing therapeutic modalities for this lethal malignancy.

DUSP16 promotes cancer chemoresistance through regulation of mitochondria-mediated cell death

Drug resistance is a major obstacle to the treatment of most human tumors. In this study, we find that dual-specificity phosphatase 16 (DUSP16) regulates resistance to chemotherapy in nasopharyngeal carcinoma, colorectal cancer, gastric and breast cancer. Cancer cells expressing higher DUSP16 are intrinsically more resistant to chemotherapy-induced cell death than cells with lower DUSP16 expression. Overexpression of DUSP16 in cancer cells leads to increased resistance to cell death upon chemotherapy treatment. In contrast, knockdown of DUSP16 in cancer cells increases their sensitivity to treatment. Mechanistically, DUSP16 inhibits JNK and p38 activation, thereby reducing BAX accumulation in mitochondria to reduce apoptosis. Analysis of patient survival in head & neck cancer and breast cancer patient cohorts supports DUSP16 as a marker for sensitivity to chemotherapy and therapeutic outcome. This study therefore identifies DUSP16 as a prognostic marker for the efficacy of chemotherapy, and as a therapeutic target for overcoming chemoresistance in cancer.

JNK signaling as a target for anticancer therapy

The JNKs are members of mitogen-activated protein kinases (MAPK) which regulate many physiological processes including inflammatory responses, macrophages, cell proliferation, differentiation, survival, and death. It is increasingly clear that the continuous activation of JNKs has a role in cancer development and progression. Therefore, JNKs represent attractive oncogenic targets for cancer therapy using small molecule kinase inhibitors. Studies showed that the two major JNK proteins JNK1 and JNK2 have opposite functions in different types of cancers, which need more specification in the design of JNK inhibitors. Some of ATP- competitive and ATP non-competitive inhibitors have been developed and widely used in vitro, but this type of inhibitors lack selectivity and inhibits phosphorylation of all JNK substrates and may lead to cellular toxicity. In this review, we summarized and discussed the strategies of JNK binding inhibitors and the role of JNK signaling in the pathogenesis of different solid and hematological malignancies.

CRTC1/MAML2 directs a PGC-1α-IGF-1 circuit that confers vulnerability to PPARγ inhibition

Mucoepidermoid carcinoma (MEC) is a life-threatening salivary gland cancer that is driven primarily by a transcriptional coactivator fusion composed of cyclic AMP-regulated transcriptional coactivator 1 (CRTC1) and mastermind-like 2 (MAML2). The mechanisms by which the chimeric CRTC1/MAML2 (C1/M2) oncoprotein rewires gene expression programs that promote tumorigenesis remain poorly understood. Here, we show that C1/M2 induces transcriptional activation of the non-canonical peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) splice variant PGC-1α4, which regulates peroxisome proliferator-activated receptor gamma (PPARγ)-mediated insulin-like growth factor 1 (IGF-1) expression. This mitogenic transcriptional circuitry is consistent across cell lines and primary tumors. C1/M2-positive tumors exhibit IGF-1 pathway activation, and small-molecule drug screens reveal that tumor cells harboring the fusion gene are selectively sensitive to IGF-1 receptor (IGF-1R) inhibition. Furthermore, this dependence on autocrine regulation of IGF-1 transcription renders MEC cells susceptible to PPARγ inhibition with inverse agonists. These results yield insights into the aberrant coregulatory functions of C1/M2 and identify a specific vulnerability that can be exploited for precision therapy.

TNF-α controls Lipocalin-2 expression in PC-3 prostate cancer cells

Prostate cancer (PCa) is one of the most common and deadly cancers in men worldwide. The surrounding tumor microenvironment (TME) is important in tumor progression, as cytokines and soluble mediators including tumor necrosis factor (TNF-α) or lipocalin-2 (LCN2) can influence tumor growth and formation of metastasis. The exact mechanisms on how these pleiotropic factors affect PCa are still unknown. In this study, we showed for the first time that LCN2 mRNA and protein expression are strongly inducible by TNF-α in the highly metastatic human PCa cell line PC-3. In addition, we observed higher levels of secreted LCN2 in cell culture medium of TNF-α-treated PC-3 cells. We found that different signaling pathways such as p38, NF-κB or JNK were activated shortly after TNF-α treatment. Moreover, the mRNA levels of IL-1β and IL-8 were also significantly increased after 24 h stimulation. Mechanistically, the NF-κB pathway and the JNK signaling axis are directly responsible for LCN2 upregulation. This was shown by the fact that pretreatment with the JNK inhibitors SP600125 or JNK-IN-8 strongly downregulated phosphorylation of c-Jun protein and markedly reduced TNF-α-mediated LCN2 upregulation in PC-3 cells. Likewise, the NF-κB inhibitor QNZ was able to repress TNF-α-induced LCN2 expression in PC-3 cells. Taking into consideration that LCN2 has been described as a tumor promoting factor in PCa, our results indicate that JNK regulates LCN2 expression and unmasks the JNK signaling axis as a possible therapeutic target for patients with PCa.