A randomized, double-blind, placebo-controlled phase 1b/2 study of ralimetinib, a p38 MAPK inhibitor, plus gemcitabine and carboplatin versus gemcitabine and carboplatin for women with recurrent platinum-sensitive ovarian cancer

The interplay of p38 MAPK signaling and mitochondrial metabolism, a dynamic target in cancer and pathological contexts

Mitochondria play a crucial role in cellular metabolism and bioenergetics, orchestrating various cellular processes, including energy production, metabolism, adaptation to stress, and redox balance. Besides, mitochondria regulate cellular metabolic homeostasis through coordination with multiple signaling pathways. Importantly, the p38 mitogen-activated protein kinase (MAPK) signaling pathway is a key player in the intricate communication with mitochondria, influencing various functions. This review explores the multifaced interaction between the mitochondria and p38 MAPK signaling and the consequent impact on metabolic alterations. Overall, the p38 MAPK pathway governs the activities of key mitochondrial proteins, which are involved in mitochondrial biogenesis, oxidative phosphorylation, thermogenesis, and iron homeostasis. Additionally, p38 MAPK contributes to the regulation of mitochondrial responses to oxidative stress and apoptosis induced by cancer therapies or natural substances by coordinating with other pathways responsible for energy homeostasis. Therefore, dysregulation of these interconnected pathways can lead to various pathologies characterized by aberrant metabolism. Consequently, gaining a deeper understanding of the interaction between mitochondria and the p38 MAPK pathway and their implications presents exciting forecasts for novel therapeutic interventions in cancer and other disorders characterized by metabolic dysregulation.

Targeting the Cdc2-like kinase 2 for overcoming platinum resistance in ovarian cancer

Platinum resistance represents a major barrier to the survival of patients with ovarian cancer (OC). Cdc2-like kinase 2 (CLK2) is a major protein kinase associated with oncogenic phenotype and development in some solid tumors. However, the exact role and underlying mechanism of CLK2 in the progression of OC is currently unknown. Using microarray gene expression profiling and immunostaining on OC tissues, we found that CLK2 was upregulated in OC tissues and was associated with a short platinum-free interval in patients. Functional assays showed that CLK2 protected OC cells from platinum-induced apoptosis and allowed tumor xenografts to be more resistant to platinum. Mechanistically, CLK2 phosphorylated breast cancer gene 1 (BRCA1) at serine 1423 (Ser1423) to enhance DNA damage repair, resulting in platinum resistance in OC cells. Meanwhile, in OC cells treated with platinum, p38 stabilized CLK2 protein through phosphorylating at threonine 343 of CLK2. Consequently, the combination of CLK2 and poly ADP-ribose polymerase inhibitors achieved synergistic lethal effect to overcome platinum resistance in patient-derived xenografts, especially those with wild-type BRCA1. These findings provide evidence for a potential strategy to overcome platinum resistance in OC patients by targeting CLK2.

Paradigm Shift: A Comprehensive Review of Ovarian Cancer Management in an Era of Advancements

Ovarian cancer (OC) is the female genital malignancy with the highest lethality. Patients present a poor prognosis mainly due to the late clinical presentation allied with the common acquisition of chemoresistance and a high rate of tumour recurrence. Effective screening, accurate diagnosis, and personalised multidisciplinary treatments are crucial for improving patients' survival and quality of life. This comprehensive narrative review aims to describe the current knowledge on the aetiology, prevention, diagnosis, and treatment of OC, highlighting the latest significant advancements and future directions. Traditionally, OC treatment involves the combination of cytoreductive surgery and platinum-based chemotherapy. Although more therapeutical approaches have been developed, the lack of established predictive biomarkers to guide disease management has led to only marginal improvements in progression-free survival (PFS) while patients face an increasing level of toxicity. Fortunately, because of a better overall understanding of ovarian tumourigenesis and advancements in the disease's (epi)genetic and molecular profiling, a paradigm shift has emerged with the identification of new disease biomarkers and the proposal of targeted therapeutic approaches to postpone disease recurrence and decrease side effects, while increasing patients' survival. Despite this progress, several challenges in disease management, including disease heterogeneity and drug resistance, still need to be overcome.

Drug repurposing for the treatment of COVID-19: Targeting nafamostat to the lungs by a liposomal delivery system

Despite tremendous global efforts since the beginning of the COVID-19 pandemic, still only a limited number of prophylactic and therapeutic options are available. Although vaccination is the most effective measure in preventing morbidity and mortality, there is a need for safe and effective post-infection treatment medication. In this study, we explored a pipeline of 21 potential candidates, examined in the Calu-3 cell line for their antiviral efficacy, for drug repurposing. Ralimetinib and nafamostat, clinically used drugs, have emerged as attractive candidates. Due to the inherent limitations of the selected drugs, we formulated targeted liposomes suitable for both systemic and intranasal administration. Non-targeted and targeted nafamostat liposomes (LipNaf) decorated with an Apolipoprotein B peptide (ApoB-P) as a specific lung-targeting ligand were successfully developed. The developed liposomal formulations of nafamostat were found to possess favorable physicochemical properties including nano size (119-147 nm), long-term stability of the normally rapidly degrading compound in aqueous solution, negligible leakage from the liposomes upon storage, and a neutral surface charge with low polydispersity index (PDI). Both nafamostat and ralimetinib liposomes showed good cellular uptake and lack of cytotoxicity, and non-targeted LipNaf demonstrated enhanced accumulation in the lungs following intranasal (IN) administration in non-infected mice. LipNaf retained its anti-SARS-CoV 2 activity in Calu 3 cells with only a modest decrease, exhibiting complete inhibition at concentrations >100 nM. IN, but not intraperitoneal (IP) treatment with targeted LipNaf resulted in a trend to reduced viral load in the lungs of K18-hACE2 mice compared to targeted empty Lip. Nevertheless, upon removal of outlier data, a statistically significant 1.9-fold reduction in viral load was achieved. This observation further highlights the importance of a targeted delivery into the respiratory tract. In summary, we were able to demonstrate a proof-of-concept of drug repurposing by liposomal formulations with anti-SARS-CoV-2 activity. The biodistribution and bioactivity studies with LipNaf suggest an IN or inhalation route of administration for optimal therapeutic efficacy.

Inhibition of a lower potency target drives the anticancer activity of a clinical p38 inhibitor

The small-molecule drug ralimetinib was developed as an inhibitor of the p38α mitogen-activated protein kinase, and it has advanced to phase 2 clinical trials in oncology. Here, we demonstrate that ralimetinib resembles EGFR-targeting drugs in pharmacogenomic profiling experiments and that ralimetinib inhibits EGFR kinase activity in vitro and in cellulo. While ralimetinib sensitivity is unaffected by deletion of the genes encoding p38α and p38β, its effects are blocked by expression of the EGFR-T790M gatekeeper mutation. Finally, we solved the cocrystal structure of ralimetinib bound to EGFR, providing further evidence that this drug functions as an ATP-competitive EGFR inhibitor. We conclude that, though ralimetinib is >30-fold less potent against EGFR compared to p38α, its ability to inhibit EGFR drives its primary anticancer effects. Our results call into question the value of p38α as an anticancer target, and we describe a multi-modal approach that can be used to uncover a drug's mechanism-of-action.

Identification of ACHE as the hub gene targeting solasonine associated with non-small cell lung cancer (NSCLC) using integrated bioinformatics analysis

Background

Solasonine, as a major biological component of Solanum nigrum L., has demonstrated anticancer effects against several malignancies. However, little is understood regarding its biological target and mechanism in non-small cell lung cancer (NSCLC).

Methods

We conducted an analysis on transcriptomic data to identify differentially expressed genes (DEGs), and employed an artificial intelligence (AI) strategy to predict the target protein for solasonine. Subsequently, genetic dependency analysis and molecular docking were performed, with Acetylcholinesterase (ACHE) selected as a pivotal marker for solasonine. We then employed a range of bioinformatic approaches to explore the relationship between ACHE and solasonine. Furthermore, we investigated the impact of solasonine on A549 cells, a human lung cancer cell line. Cell inhibition of A549 cells following solasonine treatment was analyzed using the CCK8 assay. Additionally, we assessed the protein expression of ACHE, as well as markers associated with apoptosis and inflammation, using western blotting. To investigate their functions, we employed a plasmid-based ACHE overexpression system. Finally, we performed dynamics simulations to simulate the interaction mode between solasonine and ACHE.

Results

The results of the genetic dependency analysis revealed that ACHE could be identified as the pivotal target with the highest docking affinity. The cell experiments yielded significant findings, as evidenced by the negative regulatory effect of solasonine treatment on tumor cells, as demonstrated by the CCK8 assay. Western blotting analysis revealed that solasonine treatment resulted in the downregulation of the Bcl-2/Bax ratio and upregulation of cleaved caspase-3 protein expression levels. Moreover, we observed that ACHE overexpression promoted the expression of the Bcl-2/Bax ratio and decreased cleaved caspase-3 expression in the OE-ACHE group. Notably, solasonine treatment rescued the Bcl-2/Bax ratio and cleaved caspase-3 expression in OE-ACHE cells compared to OE-ACHE cells without solasonine treatment, suggesting that solasonine induces apoptosis. Besides, solasonine exhibited its anti-inflammatory effects by inhibiting P38 MAPK. This was supported by the decline in protein levels of IL-1β and TNF-α, as well as the phosphorylated forms of JNK and P38 MAPK. The results from the molecular docking and dynamics simulations further confirmed the potent binding affinity and effective inhibitory action between solasonine and ACHE.

Conclusions

The findings of the current investigation show that solasonine exerts its pro-apoptosis and anti-inflammatory effects by suppressing the expression of ACHE.

P38 kinase in gastrointestinal cancers

Gastrointestinal cancers are a leading cause of cancer morbidity and mortality worldwide with 4.2 million new cases and 3.2 million deaths estimated in 2020. Despite the advances in primary and adjuvant therapies, patients still develop distant metastases and require novel therapies. Mitogen‑activated protein kinase (MAPK) cascades are crucial signaling pathways that regulate many cellular processes, including proliferation, differentiation, apoptosis, stress responses and cancer development. p38 Mitogen Activated Protein Kinases (p38 MAPKs) includes four isoforms: p38α (MAPK14), p38β (MAPK11), p38γ (MAPK12), and p38δ (MAPK13). p38 MAPK was first identified as a stress response protein kinase that phosphorylates different transcriptional factors. Dysregulation of p38 pathways, in particular p38γ, are associated with cancer development, metastasis, autophagy and tumor microenvironment. In this article, we provide an overview of p38 and p38γ with respect to gastrointestinal cancers. Furthermore, targeting p38γ is also discussed as a potential therapy for gastrointestinal cancers.

Characterization of p38α autophosphorylation inhibitors that target the non-canonical activation pathway

p38α is a versatile protein kinase that can control numerous processes and plays important roles in the cellular responses to stress. Dysregulation of p38α signaling has been linked to several diseases including inflammation, immune disorders and cancer, suggesting that targeting p38α could be therapeutically beneficial. Over the last two decades, numerous p38α inhibitors have been developed, which showed promising effects in pre-clinical studies but results from clinical trials have been disappointing, fueling the interest in the generation of alternative mechanisms of p38α modulation. Here, we report the in silico identification of compounds that we refer to as non-canonical p38α inhibitors (NC-p38i). By combining biochemical and structural analyses, we show that NC-p38i efficiently inhibit p38α autophosphorylation but weakly affect the activity of the canonical pathway. Our results demonstrate how the structural plasticity of p38α can be leveraged to develop therapeutic opportunities targeting a subset of the functions regulated by this pathway.

Kinase Inhibitors in the Treatment of Ovarian Cancer: Current State and Future Promises

Ovarian cancer is the deadliest gynecological cancer, the high-grade serous ovarian carcinoma (HGSC) being its most common and most aggressive form. Despite the latest therapeutical advancements following the introduction of vascular endothelial growth factor receptor (VEGFR) targeting angiogenesis inhibitors and poly-ADP-ribose-polymerase (PARP) inhibitors to supplement the standard platinum- and taxane-based chemotherapy, the expected overall survival of HGSC patients has not improved significantly from the five-year rate of 42%. This calls for the development and testing of more efficient treatment options. Many oncogenic kinase-signaling pathways are dysregulated in HGSC. Since small-molecule kinase inhibitors have revolutionized the treatment of many solid cancers due to the generality of the increased activation of protein kinases in carcinomas, it is reasonable to evaluate their potential against HGSC. Here, we present the latest concluded and on-going clinical trials on kinase inhibitors in HGSC, as well as the recent work concerning ovarian cancer patient organoids and xenograft models. We discuss the potential of kinase inhibitors as personalized treatments, which would require comprehensive assessment of the biological mechanisms underlying tumor spread and chemoresistance in individual patients, and their connection to tumor genome and transcriptome to establish identifiable subgroups of patients who are most likely to benefit from a given therapy.

Prognostic biomarker MCP-4 triggers epithelial-mesenchymal transition via the p38 MAPK pathway in ovarian cancer

BACKGROUND

Monocyte chemoattractant protein-4 (MCP-4/CCL13) is a proinflammatory factor that is overexpressed in various malignant tumors and may play an important role in tumor progression and metastasis. However, its role and mechanism of action in ovarian cancer remains unknown.

METHODS

Immunohistochemistry (IHC) was performed to detect the expression of MCP-4 in ovarian cancer tissues, and the effect of MCP-4 on patient survival and prognosis was analyzed. Overexpression and suppression of MCP-4 in ovarian cancer cell lines were then established, and their effects on cell invasion, migration, and apoptosis were studied. ES-2 cell lines were employed to establish a peritoneal dissemination model in nude mice. Western blotting was performed to detect the expression of epithelial mesenchymal transition (EMT) markers and the p38 mitogen-activated protein kinase (p38 MAPK) signaling pathway.

RESULTS

MCP-4 was highly expressed in ovarian cancer tissues and its expression level was related to the prognosis of patients with ovarian cancer. MCP-4 overexpression promoted the migration and invasion of ovarian cancer cells but inhibited apoptosis. MCP-4 overexpression increased the expression of MMP-2, MMP-9, N-cadherin, vimentin and Bcl2/Bax and decreased the expression of E-cadherin. MCP-4 overexpression increased the phosphorylation of the p38 MAPK pathway. The inhibition of MCP-4 expression indicated an opposite trend. In vivo experiments have also confirmed that MCP-4 overexpression can promote metastasis of ovarian cancer.

CONCLUSION

MCP-4 promotes ovarian cancer progression through the p38 MAPK signaling pathway, and may be a potential biomarker and therapeutic target for ovarian cancer.

Molecular mechanisms underlying the action of carcinogens in gastric cancer with a glimpse into targeted therapy

BACKGROUND

Gastric cancer imposes a substantial global health burden despite its overall incidence decrease. A broad spectrum of inherited, environmental and infectious factors contributes to the development of gastric cancer. A profound understanding of the molecular underpinnings of gastric cancer has lagged compared to several other tumors with similar incidence and morbidity rates, owing to our limited knowledge of the role of carcinogens in this malignancy. The International Agency for Research on Cancer (IARC) has classified gastric carcinogenic agents into four groups based on scientific evidence from human and experimental animal studies. This review aims to explore the potential comprehensive molecular and biological impacts of carcinogens on gastric cancer development and their interactions and interferences with various cellular signaling pathways.

CONCLUSIONS

In this review, we highlight recent clinical trial data reported in the literature dealing with different ways to target various carcinogens in gastric cancer. Moreover, we touch upon other multidisciplinary therapeutic approaches such as surgery, adjuvant and neoadjuvant chemotherapy. Rational clinical trials focusing on identifying suitable patient populations are imperative to the success of single-agent therapeutics. Novel insights regarding signaling pathways that regulate gastric cancer can potentially improve treatment responses to targeted therapy alone or in combination with other/conventional treatments. Preventive strategies such as control of H. pylori infection through eradication or immunization as well as dietary habit and lifestyle changes may reduce the incidence of this multifactorial disease, especially in high prevalence areas. Further in-depth understanding of the molecular mechanisms involved in the role of carcinogenic agents in gastric cancer development may offer valuable information and update state-of-the-art resources for physicians and researchers to explore novel ways to combat this disease, from bench to bedside. A schematic outlining of the interaction between gastric carcinogenic agents and intracellular pathways in gastric cancer H. pylori stimulates multiple intracellular pathways, including PI3K/AKT, NF-κB, Wnt, Shh, Ras/Raf, c-MET, and JAK/STAT, leading to epithelial cell proliferation and differentiation, apoptosis, survival, motility, and inflammatory cytokine release. EBV can stimulate intracellular pathways such as the PI3K/Akt, RAS/RAF, JAK/STAT, Notch, TGF-β, and NF-κB, leading to cell survival and motility, proliferation, invasion, metastasis, and the transcription of anti-apoptotic genes and pro-inflammatory cytokines. Nicotine and alcohol can lead to angiogenesis, metastasis, survival, proliferation, pro-inflammatory, migration, and chemotactic by stimulating various intracellular signaling pathways such as PI3K/AKT, NF-κB, Ras/Raf, ROS, and JAK/STAT. Processed meat contains numerous carcinogenic compounds that affect multiple intracellular pathways such as sGC/cGMP, p38 MAPK, ERK, and PI3K/AKT, leading to anti-apoptosis, angiogenesis, metastasis, inflammatory responses, proliferation, and invasion. Lead compounds may interact with multiple signaling pathways such as PI3K/AKT, NF-κB, Ras/Raf, DNA methylation-dependent, and epigenetic-dependent, leading to tumorigenesis, carcinogenesis, malignancy, angiogenesis, DNA hypermethylation, cell survival, and cell proliferation. Stimulating signaling pathways such as PI3K/Akt, RAS/RAF, JAK/STAT, WNT, TGF-β, EGF, FGFR2, and E-cadherin through UV ionizing radiation leads to cell survival, proliferation, and immortalization in gastric cancer. The consequence of PI3K/AKT, NF-κB, Ras/Raf, ROS, JAK/STAT, and WNT signaling stimulation by the carcinogenic component of Pickled vegetables and salted fish is the Warburg effect, tumorigenesis, angiogenesis, proliferation, inflammatory response, and migration.

Blockades of effector T cell senescence and exhaustion synergistically enhance antitumor immunity and immunotherapy

BACKGROUND

Current immunotherapies still have limited successful rates among cancers. It is now recognized that T cell functional state in the tumor microenvironment (TME) is a key determinant for effective antitumor immunity and immunotherapy. In addition to exhaustion, cellular senescence in tumor-infiltrating T cells (TILs) has recently been identified as an important T cell dysfunctional state induced by various malignant tumors. Therefore, a better understanding of the molecular mechanism responsible for T cell senescence in the TME and development of novel strategies to prevent effector T cell senescence are urgently needed for cancer immunotherapy.

METHODS

Senescent T cell populations in the TMEs in mouse lung cancer, breast cancer, and melanoma tumor models were evaluated. Furthermore, T cell senescence induced by mouse tumor and regulatory T (Treg) cells in vitro was determined with multiple markers and assays, including real-time PCR, flow cytometry, and histochemistry staining. Loss-of-function strategies with pharmacological inhibitors and the knockout mouse model were used to identify the potential molecules and pathways involved in T cell senescence. In addition, melanoma mouse tumor immunotherapy models were performed to explore the synergistical efficacy of antitumor immunity via prevention of tumor-specific T cell senescence combined with anti-programmed death-ligand 1 (anti-PD-L1) checkpoint blockade therapy.

RESULTS

We report that both mouse malignant tumor cells and Treg cells can induce responder T cell senescence, similar as shown in human Treg and tumor cells. Accumulated senescent T cells also exist in the TME in tumor models of lung cancer, breast cancer and melanoma. Induction of ataxia-telangiectasia mutated protein (ATM)-associated DNA damage is the cause for T cell senescence induced by both mouse tumor cells and Treg cells, which is also regulated by mitogen-activated protein kinase (MAPK) signaling. Furthermore, blockages of ATM-associated DNA damage and/or MAPK signaling pathways in T cells can prevent T cell senescence mediated by tumor cells and Treg cells in vitro and enhance antitumor immunity and immunotherapy in vivo in adoptive transfer T cell therapy melanoma models. Importantly, prevention of tumor-specific T cell senescence via ATM and/or MAPK signaling inhibition combined with anti-PD-L1 checkpoint blockade can synergistically enhance antitumor immunity and immunotherapy in vivo.

CONCLUSIONS

These studies prove the novel concept that targeting both effector T cell senescence and exhaustion is an effective strategy and can synergistically enhance cancer immunotherapy.

The functional role of p38 MAPK pathway in malignant brain tumors

Gliomas are extremely debilitating malignant brain tumors with very limited response to therapies. The initiation and progression of gliomas can be attributed to several molecular abnormalities, such as mutations in important regulatory networks. In this regard, the mitogen-activated protein kinases (MAPKs) arise as key signaling pathways involved in cell proliferation, survival, and differentiation. MAPK pathway has been altered in most glial tumors. In glioma cells, the activation of p38 MAPK contributes to tumor invasion and metastasis and is positively correlated with tumor grade, being considered a potential oncogenic factor contributing to brain tumorigenesis and chemotherapy resistance. Hence, a better understanding of glioma pathogenesis is essential to the advancement of therapies that provide extended life expectancy for glioma patients. This review aims to explore the role of the p38 MAPK pathway in the genesis and progression of malignant brain tumors.

Targeting DUSP Activity as a Treatment for High-Grade Serous Ovarian Carcinoma

Identifying novel, durable treatments for high-grade serous ovarian cancer (HGSOC) is paramount to extend both progression-free survival (PFS) and overall survival (OS) in patients afflicted with this disease. Dual-specificity phosphatase 1 (DUSP1) was identified as one of seven genes that may significantly affect prognosis in patients with HGSOC; however, the role of DUSP inhibition (DUSPi) in the treatment of HGSOC remains largely unknown. In this study, we show that DUSP1 is highly expressed in HGSOC and confers worse PFS and OS. Further, we corroborate data that show DUSP1 expression is directly associated with therapy resistance. Using a tissue microarray of 137 different serous ovarian carcinomas, we demonstrate the high expression of DUSP1 in primary and recurrent serous ovarian cancer. In both acquired and de novo therapy HGSOC-resistant models, DUSPi both inhibited cellular proliferation and promoted cell death. RPPA analysis of HGSOC cells revealed DUSPi led to the differential regulation of several pathways, including AMPK and mTORC. Further, in a patient-derived xenograft HGSOC model, DUSPi significantly inhibited tumor progression.

Efficacy and Safety of Placebo During the Maintenance Therapy of Ovarian Cancer in Randomized Controlled Trials: A Systematic Review and Meta-analysis

Introduction

This meta-analysis evaluated the efficacy and safety of placebo during the maintenance therapy of ovarian cancer (OC) patients in randomized controlled trials (RCTs).

Methods

A comprehensive literature review was performed for RCTs published up to and including August 2020 from four electronic databases. We analyzed the efficacy and safety in the control arms of the maintenance therapy in advanced OC patients. Hazard ratios (HRs) and the corresponding 95% confidence intervals (CIs) of progression-free survival (PFS) and overall survival (OS) were estimated in the placebo arms and the observation arms, respectively, using the Frequency Framework method. We also calculated the incidences of common adverse effects (AEs) in the placebo arms.

Results

In total, 41 articles with 20,099 (4,787 in the placebo arms, 3,420 in the observation arms, and 11,892 in the experiment arms) patients were included in this meta-analysis. Compared with observation, placebo did not improve or reduce PFS (HR, 1.02; 95% CI, 0.87–1.20; P = 0.81) and OS (HR, 1.02; 95% CI, 0.89–1.16; P = 0.76) of OC patients, while other treatments, except for radiotherapy, significantly improved PFS and OS (all P < 0.05). The incidences of AEs produced by placebo were 94.03% in all grades and 20.22% in grade ≥3. The incidences of AEs were 29.75% in fatigue, 26.38% in nausea, 24.34% in abdominal pain, 18.92% in constipation, 16.65% in diarrhea, 14.55% in vomiting, 13.89% in hypertension, and 13.14% in headache.

Conclusions

Placebo did not improve or reduce the PFS and OS benefits of OC patients in RCTs but increased the incidences of AEs.

Role of p38 MAP kinase in cancer stem cells and metastasis

Therapeutic resistance and metastatic progression are responsible for the majority of cancer mortalities. In particular, the development of resistance is a significant barrier to the efficacy of cancer treatments such as chemotherapy, radiotherapy, targeted therapies, and immunotherapies. Cancer stem cells (CSCs) underlie treatment resistance and metastasis. p38 mitogen-activated protein kinase (p38 MAPK) is downstream of several CSC-specific signaling pathways, and it plays an important role in CSC development and maintenance and contributes to metastasis and chemoresistance. Therefore, the development of therapeutic approaches targeting p38 can sensitize tumors to chemotherapy and prevent metastatic progression.

Intra-epithelial non-canonical Activin A signaling safeguards prostate progenitor quiescence

The healthy prostate is a relatively quiescent tissue. Yet, prostate epithelium overgrowth is a common condition during aging, associated with urinary dysfunction and tumorigenesis. For over thirty years, TGF-β ligands have been known to induce cytostasis in a variety of epithelia, but the intracellular pathway mediating this signal in the prostate, and its relevance for quiescence, have remained elusive. Here, using mouse prostate organoids to model epithelial progenitors, we find that intra-epithelial non-canonical Activin A signaling inhibits cell proliferation in a Smad-independent manner. Mechanistically, Activin A triggers Tak1 and p38 ΜAPK activity, leading to p16 and p21 nuclear import. Spontaneous evasion from this quiescent state occurs upon prolonged culture, due to reduced Activin A secretion, a condition associated with DNA replication stress and aneuploidy. Organoids capable to escape quiescence in vitro are also able to implant with increased frequency into immunocompetent mice. This study demonstrates that non-canonical Activin A signaling safeguards epithelial quiescence in the healthy prostate, with potential implications for the understanding of cancer initiation, and the development of therapies targeting quiescent tumor progenitors.

Inhibitors and Activators of the p38 Mitogen- Activated MAP Kinase (MAPK) Family as Drugs to Treat Cancer and Inflammation

The p38 MAP kinases are a sub-family of the broad group of mitogen-activated serine-threonine protein kinases. The best-characterised, most widely expressed, and most targeted by drugs is p38α MAP kinase. This review briefly summarises the place of p38α MAP kinase in cellular signalling and discusses the structures and activity profiles of representative examples of the major classes of inhibitors and activators (both synthetic compounds and natural products) of this enzyme. Primary screening was primarily direct in vitro inhibition of isolated p38α enzyme.

Functional Roles of JNK and p38 MAPK Signaling in Nasopharyngeal Carcinoma

c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) family members integrate signals that affect proliferation, differentiation, survival, and migration in a cell context- and cell type-specific way. JNK and p38 MAPK activities are found upregulated in nasopharyngeal carcinoma (NPC). Studies have shown that activation of JNK and p38 MAPK signaling can promote NPC oncogenesis by mechanisms within the cancer cells and interactions with the tumor microenvironment. They regulate multiple transcription activities and contribute to tumor-promoting processes, ranging from cell proliferation to apoptosis, inflammation, metastasis, and angiogenesis. Current literature suggests that JNK and p38 MAPK activation may exert pro-tumorigenic functions in NPC, though the underlying mechanisms are not well documented and have yet to be fully explored. Here, we aim to provide a narrative review of JNK and p38 MAPK pathways in human cancers with a primary focus on NPC. We also discuss the potential therapeutic agents that could be used to target JNK and p38 MAPK signaling in NPC, along with perspectives for future works. We aim to inspire future studies further delineating JNK and p38 MAPK signaling in NPC oncogenesis which might offer important insights for better strategies in diagnosis, prognosis, and treatment decision-making in NPC patients.

Strategies for Improving Photodynamic Therapy Through Pharmacological Modulation of the Immediate Early Stress Response

Photodynamic therapy (PDT) is a minimally to noninvasive treatment modality that has emerged as a promising alternative to conventional cancer treatments. PDT induces hyperoxidative stress and disrupts cellular homeostasis in photosensitized cancer cells, resulting in cell death and ultimately removal of the tumor. However, various survival pathways can be activated in sublethally afflicted cancer cells following PDT. The acute stress response is one of the known survival pathways in PDT, which is activated by reactive oxygen species and signals via ASK-1 (directly) or via TNFR (indirectly). The acute stress response can activate various other survival pathways that may entail antioxidant, pro-inflammatory, angiogenic, and proteotoxic stress responses that culminate in the cancer cell's ability to cope with redox stress and oxidative damage. This review provides an overview of the immediate early stress response in the context of PDT, mechanisms of activation by PDT, and molecular intervention strategies aimed at inhibiting survival signaling and improving PDT outcome.

The p38 MAPK Components and Modulators as Biomarkers and Molecular Targets in Cancer

The mitogen-activated protein kinase (MAPK) family is an important bridge in the transduction of extracellular and intracellular signals in different responses at the cellular level. Within this MAPK family, the p38 kinases can be found altered in various diseases, including cancer, where these kinases play a fundamental role, sometimes with antagonistic mechanisms of action, depending on several factors. In fact, this family has an immense number of functionalities, many of them yet to be discovered in terms of regulation and action in different types of cancer, being directly involved in the response to cancer therapies. To date, three main groups of MAPKs have been identified in mammals: the extracellular signal-regulated kinases (ERK), Jun N-terminal kinase (JNK), and the different isoforms of p38 (α, β, γ, δ). In this review, we highlight the mechanism of action of these kinases, taking into account their extensive regulation at the cellular level through various modifications and modulations, including a wide variety of microRNAs. We also analyze the importance of the different isoforms expressed in the different tissues and their possible role as biomarkers and molecular targets. In addition, we include the latest preclinical and clinical trials with different p38-related drugs that are ongoing with hopeful expectations in the present/future of developing precision medicine in cancer.

Novel Pathways for Targeting Tumor Angiogenesis in Metastatic Breast Cancer

Breast cancer is the most common cancer affecting women and is the second leading cause of cancer related death worldwide. Angiogenesis, the process of new blood vessel development from pre-existing vasculature, has been implicated in the growth, progression, and metastasis of cancer. Tumor angiogenesis has been explored as a key therapeutic target for decades, as the blockade of this process holds the potential to reduce the oxygen and nutrient supplies that are required for tumor growth. However, many existing anti-angiogenic approaches, such as those targeting Vascular Endothelial Growth Factor, Notch, and Angiopoietin signaling, have been associated with severe side-effects, limited survival advantage, and enhanced cancer regrowth rates. To address these setbacks, alternative pathways involved in the regulation of tumor angiogenesis are being explored, including those involving Bone Morphogenetic Protein-9 signaling, the Sonic Hedgehog pathway, Cyclooxygenase-2, p38-mitogen-activated protein kinase, and Chemokine Ligand 18. This review article will introduce the concept of tumor angiogenesis in the context of breast cancer, followed by an overview of current anti-angiogenic therapies, associated resistance mechanisms and novel therapeutic targets.

Silencing of the lncRNA H19 enhances sensitivity to X-ray and carbon-ions through the miR-130a-3p /WNK3 signaling axis in NSCLC cells

Background

The lncRNA H19 is believed to act as an oncogene in various types of tumors and is considered to be a therapeutic target and diagnostic marker. However, the role of the lncRNA H19 in regulating the radiosensitivity of non-small cell lung cancer (NSCLC) cells is unknown.

Methods

The expression profiles of lncRNAs in NSCLC were explored via transcriptome sequencing. CCK-8, EdU incorporation and clonogenic survival assays were conducted to evaluate the proliferation and radiosensitivity of NSCLC cells. Flow cytometry and Western blotting were conducted to measure the level of apoptosis. The binding relationship between the lncRNA H19 and miR-130a-3p was determined by a dual-luciferase reporter assay. A binding relationship was also identified between miR-130a-3p and With-No-Lysine Kinase 3 (WNK3).

Results

Expression patterns of lncRNAs revealed that the lncRNA H19 was upregulated in radioresistant NSCLC (A549-R11) cells compared with A549 cells. Knockdown of the lncRNA H19 enhanced the sensitivity of NSCLC cell lines to X-ray and carbon ion irradiation. Mechanistically, the lncRNA H19 serves as a sponge of miR-130a-3p, which downregulates WNK3 expression. The lncRNA H19–miR-130a-3p–WNK3 axis modulates radiosensitivity by regulating apoptosis in NSCLC cell lines.

Conclusion

Knockdown of the lncRNA H19 promotes the sensitivity of NSCLC cells to X-ray and carbon ion irradiation. Hence, the lncRNA H19 might function as a potential therapeutic target that enhances the antitumor effects of radiotherapy in NSCLC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02268-1.

Impact of Value Frameworks on the Magnitude of Clinical Benefit: Evaluating a Decade of Randomized Trials for Systemic Therapy in Solid Malignancies

In the era of rapid development of new, expensive cancer therapies, value frameworks have been developed to quantify clinical benefit (CB). We assessed the evolution of CB since the 2015 introduction of The American Society of Clinical Oncology and The European Society of Medical Oncology value frameworks. Randomized clinical trials (RCTs) assessing systemic therapies for solid malignancies from 2010 to 2020 were evaluated and CB (Δ) in 2010–2014 (pre-value frameworks (PRE)) were compared to 2015–2020 (POST) for overall survival (OS), progression-free survival (PFS), response rate (RR), and quality of life (QoL). In the 485 studies analyzed (12% PRE and 88% POST), the most common primary endpoint was PFS (49%), followed by OS (20%), RR (12%), and QoL (6%), with a significant increase in OS and decrease in RR as primary endpoints in the POST era (p = 0.011). Multivariable analyses revealed significant improvement in ΔOS POST (OR 2.86, 95% CI 0.46 to 5.26, p = 0.02) while controlling for other variables. After the development of value frameworks, median ΔOS improved minimally. The impact of value frameworks has yet to be fully realized in RCTs. Efforts to include endpoints shown to impact value, such as QoL, into clinical trials are warranted.

MicroRNA-based signatures impacting clinical course and biology of ovarian cancer: a miRNOmics study

Background

In Western countries, ovarian cancer (OC) still represents the leading cause of gynecological cancer-related deaths, despite the remarkable gains in therapeutical options. Novel biomarkers of early diagnosis, prognosis definition and prediction of treatment outcomes are of pivotal importance. Prior studies have shown the potentials of micro-ribonucleic acids (miRNAs) as biomarkers for OC and other cancers.

Methods

We focused on the prognostic and/or predictive potential of miRNAs in OC by conducting a comprehensive array profiling of miRNA expression levels in ovarian tissue samples from 17 non-neoplastic controls, and 60 tumor samples from OC patients treated at the Regina Elena National Cancer Institute (IRE). A set of 54 miRNAs with differential expression in tumor versus normal samples (T/N-deregulated) was identified in the IRE cohort and validated against data from the Cancer Genoma Atlas (TCGA) related to 563 OC patients and 8 non-neoplastic controls. The prognostic/predictive role of the selected 54 biomarkers was tested in reference to survival endpoints and platinum resistance (P-res).

Results

In the IRE cohort, downregulation of the 2 miRNA-signature including miR-99a-5p and miR-320a held a negative prognostic relevance, while upregulation of miR-224-5p was predictive of less favorable event free survival (EFS) and P-res. Data from the TCGA showed that downregulation of 5 miRNAs, i.e., miR-150, miR-30d, miR-342, miR-424, and miR-502, was associated with more favorable EFS and overall survival outcomes, while miR-200a upregulation was predictive of P-res. The 9 miRNAs globally identified were all included into a single biologic signature, which was tested in enrichment analysis using predicted/validated miRNA target genes, followed by network representation of the miRNA-mRNA interactions.

Conclusions

Specific dysregulated microRNA sets in tumor tissue showed predictive/prognostic value in OC, and resulted in a promising biological signature for this disease.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40364-021-00289-6.

Integrating Proteomics for Facilitating Drug Identification and Repurposing During an Emerging Virus Pandemic

The coronavirus disease 2019 (COVID-19) pandemic has disrupted global healthcare and economic systems throughout 2020 with no clear end in sight. While the pandemic continues to have deleterious effects across the globe, mechanisms for disrupting disease transmission have relied on behavioral controls (e.g., social distancing, masks, and hygiene) as there are currently no vaccines approved for use and limited therapeutic options. As this pandemic has demonstrated our vulnerability to newly emerging viruses, there has been strong interest in utilizing proteomics approaches to identify targets for repurposed drugs as novel therapeutic candidates that could be fast-tracked for human use. Building on a previous discussion on the combination of proteomics technologies with clinical data for combating emerging viruses, we discuss how these technologies are being employed for COVID-19 and the current state of knowledge regarding repurposed drugs in these efforts.

Targeting cell cycle regulation via the G2-M checkpoint for synthetic lethality in melanoma

Disruption of cell cycle checkpoints has been well established as a hallmark of cancer. In particular, the G1-S transition mediated by the cyclin D-cyclin-dependent kinase 4/6 (CDK4/6) pathway is dysregulated in more than 90% of melanoma cases. Therefore, tumor cells mainly rely on the G2-M checkpoint to halt the cell cycle in order to repair DNA damage. Here, we review the promising method of cell cycle-mediated synthetic lethality for melanoma treatment, which entails exploiting somatically acquired mutations in the G1-S transition with inhibitors of the G2-M transition in order to specifically kill melanoma cells. The idea stems from the theory that melanoma cells lacking G1-S checkpoints are particularly vulnerable to mitotic catastrophe when presented with G2-M checkpoint inhibition in addition to DNA damage, whereas normal cells with intact G1-S checkpoints should theoretically be spared. This review explores the link between cell cycle dysregulation and synthetic lethality in melanoma cells and discusses potential future applications for this treatment.

p38 MAPK Inhibition Mitigates Hypoxia-Induced AR Signaling in Castration-Resistant Prostate Cancer

Simple Summary

Progression of prostate cancer to a castration-resistant state is associated with poor patient outcomes, and new therapeutic targeting approaches are needed. Poorly oxygenated (hypoxic) cancer cells are resistant to many treatment modalities, and it is therefore important that novel therapies also target these cells. Here we show that targeting the p38 MAPK protein kinase can inhibit growth and survival of both well-oxygenated and hypoxic castration resistant prostate cancer cells and prolong survival of tumor bearing mice. p38 MAPK targeting inhibited phosphorylation of the chaperone protein Hsp27 and activity of the androgen receptor. This demonstrates that prostate cancer cells can remain dependent on the p38 MAPK/Hsp27 signaling axis upon progression to castration-resistance, and that hypoxia does not offer protection against targeting this pathway.

Abstract

Background: Aberrant androgen receptor (AR) signaling is a major driver of castration-resistant prostate cancer (CRPC). Tumor hypoxia increases AR signaling and is associated with treatment resistance in prostate cancer. Heat shock protein 27 (Hsp27) is a molecular chaperone that is activated in response to heat shock and hypoxia. Hsp27 has previously been reported to facilitate AR nuclear translocation in a p38 mitogen-activated protein kinase (MAPK) dependent manner in castration-sensitive prostate cancer cell lines. Here, we evaluated the potential for inhibiting p38 MAPK/Hsp27 mediated AR signaling under normoxia and hypoxia in experimental models of CRPC. Methods: We inhibited p38 MAPK with SB203580 in prostate cancer cell lines and measured Hsp27 phosphorylation, AR activity, cell proliferation, and clonogenicity under normoxia and hypoxia. AR activity was measured using an androgen response element driven reporter assay and qPCR to measure expression of AR target genes. Xenograft-bearing mice were treated with SB203580 to measure tumor growth and serum prostate specific antigen (PSA). Results: Our results indicate that p38 MAPK and Hsp27 are activated under normoxia and hypoxia in response to androgens in CRPC cells. p38 MAPK inhibition diminished Hsp27 activation and the hypoxia-mediated increase in AR activity. Additionally, inhibition of p38 MAPK activity decreased proliferation and survival of CRPC cells in vitro and prolonged the survival of tumor-bearing mice. Conclusions: These results suggest that p38 MAPK inhibition may represent a therapeutic strategy to disrupt AR signaling in the heterogeneous CRPC tumor microenvironment.

Host-directed therapies against early-lineage SARS-CoV-2 retain efficacy against B.1.1.7 variant

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has resulted in millions of deaths worldwide and massive societal and economic burden. Recently, a new variant of SARS-CoV-2, known as B.1.1.7, was first detected in the United Kingdom and is spreading in several other countries, heightening public health concern and raising questions as to the resulting effectiveness of vaccines and therapeutic interventions. We and others previously identified host-directed therapies with antiviral efficacy against SARS-CoV-2 infection. Less prone to the development of therapy resistance, host-directed drugs represent promising therapeutic options to combat emerging viral variants as host genes possess a lower propensity to mutate compared to viral genes. Here, in the first study of the full-length B.1.1.7 variant virus , we find two host-directed drugs, plitidepsin (aplidin; inhibits translation elongation factor eEF1A) and ralimetinib (inhibits p38 MAP kinase cascade), as well as remdesivir, to possess similar antiviral activity against both the early-lineage SARS-CoV-2 and the B.1.1.7 variant, evaluated in both human gastrointestinal and lung epithelial cell lines. We find that plitidepsin is over an order of magnitude more potent than remdesivir against both viruses. These results highlight the importance of continued development of host-directed therapeutics to combat current and future coronavirus variant outbreaks.

Ovarian cancer: new strategies and emerging targets for the treatment of patients with advanced disease

Recently approved therapies have contributed to a significant progress in the management of ovarian cancer; yet, more options are needed to further improve outcomes in patients with advanced disease. Here we review the rationale and ongoing clinical trials of novel combination strategies involving chemotherapy, poly ADP ribose polymerase, programmed death 1 (PD-1)/PD-ligand 1 immune checkpoint and/or vascular endothelial growth factor receptor inhibitors. Further, we discuss novel agents aimed at targets associated with ovarian cancer growth or progression that are emerging as potential new treatment approaches. Among them, agents targeted to folate receptor α, tissue factor, and protein kinase-mediated pathways (WEE1 kinase, phosphatidylinositol-3 kinase α, cell cycle checkpoint kinase 1/2, ATR kinase) are currently in clinical development as mono- or combination therapies. If successful, findings from these extensive development efforts may further transform treatment of patients with advanced ovarian cancer.

Diversity and versatility of p38 kinase signalling in health and disease

The ability of cells to deal with different types of stressful situations in a precise and coordinated manner is key for survival and involves various signalling networks. Over the past 25 years, p38 kinases — in particular, p38α — have been implicated in the cellular response to stress at many levels. These span from environmental and intracellular stresses, such as hyperosmolarity, oxidative stress or DNA damage, to physiological situations that involve important cellular changes such as differentiation. Given that p38α controls a plethora of functions, dysregulation of this pathway has been linked to diseases such as inflammation, immune disorders or cancer, suggesting the possibility that targeting p38α could be of therapeutic interest. In this Review, we discuss the organization of this signalling pathway focusing on the diversity of p38α substrates, their mechanisms and their links to particular cellular functions. We then address how the different cellular responses can be generated depending on the signal received and the cell type, and highlight the roles of this kinase in human physiology and in pathological contexts.

p38α — the best-characterized member of the p38 kinase family — is a key mediator of cellular stress responses. p38α is activated by a plethora of signals and functions through a multitude of substrates to regulate different cellular behaviours. Understanding context-dependent p38α signalling provides important insights into p38α roles in physiology and pathology.

Phosphorylation of the Regulators, a Complex Facet of NF-κB Signaling in Cancer

The nuclear factor kappa B (NF-κB) is a ubiquitous transcription factor central to inflammation and various malignant diseases in humans. The regulation of NF-κB can be influenced by a myriad of post-translational modifications (PTMs), including phosphorylation, one of the most popular PTM formats in NF-κB signaling. The regulation by phosphorylation modification is not limited to NF-κB subunits, but it also encompasses the diverse regulators of NF-κB signaling. The differential site-specific phosphorylation of NF-κB itself or some NF-κB regulators can result in dysregulated NF-κB signaling, often culminating in events that induce cancer progression and other hyper NF-κB related diseases, such as inflammation, cardiovascular diseases, diabetes, as well as neurodegenerative diseases, etc. In this review, we discuss the regulatory role of phosphorylation in NF-κB signaling and the mechanisms through which they aid cancer progression. Additionally, we highlight some of the known and novel NF-κB regulators that are frequently subjected to phosphorylation. Finally, we provide some future perspectives in terms of drug development to target kinases that regulate NF-κB signaling for cancer therapeutic purposes.

Impact of Gastrointestinal Symptoms in COVID-19: a Molecular Approach

The pandemic of novel coronavirus disease (COVID-19) caused by the Severe Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) creates an immense menace to public health worldwide. Currently, the World Health Organization (WHO) has recognized the novel coronavirus as the main cause of global pandemic. Patients infected with this virus generally show fever, nausea, and respiratory illness, while some patients also manifest gastrointestinal symptoms such as abdominal pain, vomiting, and diarrhea. Traces of SARS-CoV-2 RNA have been found in gastrointestinal cells. Further angiotensin converting enzyme 2 (ACE2) the known receptor for the virus is extensively expressed in these cells. This implies that gastrointestinal tract can be infected and can also present them as a replication site for SARS-CoV-2, but since this infection may lead to multiple organ failure, therefore identification of another receptor is a plausible choice. This review aims to provide comprehensive information about probable receptors such as sialic acid and CD147 which may facilitate the virus entry. Several potential targets are mentioned which can be used as a therapeutic approach for COVID-19 and associated GI disorders. The gut microbiomes are responsible for high levels of interferon-gamma which causes hyper-inflammation and exacerbates the severity of the disease. Briefly, this article highlights the gut microbiome’s relation and provides potential diagnostic approaches like RDT and LC-MS for sensitive and specific identification of viral proteins. Altogether, this article reviews epidemiology, probable receptors and put forward the tentative ideas of the therapeutic targets and diagnostic methods for COVID-19 with gastrointestinal aspect of disease.

Phase 1 trial of ralimetinib (LY2228820) with radiotherapy plus concomitant temozolomide in the treatment of newly diagnosed glioblastoma

BACKGROUND AND PURPOSE

This phase 1 trial aimed to determine the maximum tolerated dose (MTD; primary objective) of a p38-MAPK inhibitor, ralimetinib, with radiotherapy (RT) and chemotherapy (TMZ), in the treatment of newly diagnosed glioblastoma (GBM) patients.

MATERIALS AND METHODS

The study was designed as an open-label dose-escalation study driven by a Tite-CRM design and followed by an expansion cohort. Ralimetinib was administered orally every 12 h, 7 days a week, for 2 cycles of 2 weeks at a dose of 100, 200 or 300 mg/12 h. Patients received ralimetinib added to standard concurrent RT (60 Gy in 30 fractions) with TMZ (75 mg/m²/day) and 6 cycles of adjuvant TMZ (150-200 mg/m² on days 1-5 every 28 days).

RESULTS

The MTD of ralimetinib was 100 mg/12 h with chemoradiotherapy. The three patients treated at 200 mg/12 h presented a dose-limiting toxicity: one patient had a grade 3 face edema, and two patients had a grade 3 rash and grade 3 hepatic cytolysis (66%). Of the 18 enrolled patients, 15 received the MTD of ralimetinib. At the MTD, the grade ≥ 3 adverse events during concomitant chemoradiotherapy were hepatic cytolysis (2/15 patients), dermatitis/rash (1/15), lymphopenia (1/15) and nausea/vomiting (1/15). No interaction of TMZ and ralimetinib when administrated concomitantly has been observed. Inhibition of pMAPKAP-K2 (-54%) was observed in peripheral blood mononuclear cells.

CONCLUSION

This phase 1 trial is the first trial to study the combination of a p38-MAPK inhibitor, ralimetinib, with radiotherapy (RT) and chemotherapy (TMZ), in the treatment of newly diagnosed glioblastoma (GBM) patients. The MTD of ralimetinib was 100 mg/12 h. The most frequent dose-limiting toxicities were hepatic cytolysis and rash.

Nuclear P38: Roles in Physiological and Pathological Processes and Regulation of Nuclear Translocation

The p38 mitogen-activated protein kinase (p38MAPK, termed here p38) cascade is a central signaling pathway that transmits stress and other signals to various intracellular targets in the cytoplasm and nucleus. More than 150 substrates of p38α/β have been identified, and this number is likely to increase. The phosphorylation of these substrates initiates or regulates a large number of cellular processes including transcription, translation, RNA processing and cell cycle progression, as well as degradation and the nuclear translocation of various proteins. Being such a central signaling cascade, its dysregulation is associated with many pathologies, particularly inflammation and cancer. One of the hallmarks of p38α/β signaling is its stimulated nuclear translocation, which occurs shortly after extracellular stimulation. Although p38α/β do not contain nuclear localization or nuclear export signals, they rapidly and robustly translocate to the nucleus, and they are exported back to the cytoplasm within minutes to hours. Here, we describe the physiological and pathological roles of p38α/β phosphorylation, concentrating mainly on the ill-reviewed regulation of p38α/β substrate degradation and nuclear translocation. In addition, we provide information on the p38α/β ’s substrates, concentrating mainly on the nuclear targets and their role in p38α/β functions. Finally, we also provide information on the mechanisms of nuclear p38α/β translocation and its use as a therapeutic target for p38α/β-dependent diseases.

Senescence in the Development and Response to Cancer with Immunotherapy: A Double-Edged Sword

Cellular senescence was first described as a physiological tumor cell suppressor mechanism that leads to cell growth arrest with production of the senescence-associated secretory phenotype known as SASP. The main role of SASP in physiological conditions is to attract immune cells to clear senescent cells avoiding tumor development. However, senescence can be damage-associated and, depending on the nature of these stimuli, additional types of senescence have been described. In the context of cancer, damage-associated senescence has been described as a consequence of chemotherapy treatments that were initially thought of as a tumor suppressor mechanism. However, in certain contexts, senescence after chemotherapy can promote cancer progression, especially when immune cells become senescent and cannot clear senescent tumor cells. Moreover, aging itself leads to continuous inflammaging and immunosenescence which are responsible for rewiring immune cells to become defective in their functionality. Here, we define different types of senescence, pathways that activate them, and functions of SASP in these events. Additionally, we describe the role of senescence in cancer and its treatments, including how aging and chemotherapy contribute to senescence in tumor cells, before focusing on immune cell senescence and its role in cancer. Finally, we discuss potential therapeutic interventions to reverse cell senescence.

The p38 Pathway: From Biology to Cancer Therapy

The p38 MAPK pathway is well known for its role in transducing stress signals from the environment. Many key players and regulatory mechanisms of this signaling cascade have been described to some extent. Nevertheless, p38 participates in a broad range of cellular activities, for many of which detailed molecular pictures are still lacking. Originally described as a tumor-suppressor kinase for its inhibitory role in RAS-dependent transformation, p38 can also function as a tumor promoter, as demonstrated by extensive experimental data. This finding has prompted the development of specific inhibitors that have been used in clinical trials to treat several human malignancies, although without much success to date. However, elucidating critical aspects of p38 biology, such as isoform-specific functions or its apparent dual nature during tumorigenesis, might open up new possibilities for therapy with unexpected potential. In this review, we provide an extensive description of the main biological functions of p38 and focus on recent studies that have addressed its role in cancer. Furthermore, we provide an updated overview of therapeutic strategies targeting p38 in cancer and promising alternatives currently being explored.