Therapeutically exploiting STAT3 activity in cancer - using tissue repair as a road map

Inhibition of STAT3: A promising approach to enhancing the efficacy of chemotherapy in medulloblastoma

Medulloblastoma is a type of brain cancer that primarily affects children. While chemotherapy has been shown to be effective in treating medulloblastoma, the development of chemotherapy resistance remains a challenge. One potential therapeutic approach is to selectively inhibit the inducible transcription factor called STAT3, which is known to play a crucial role in the survival and growth of tumor cells. The activation of STAT3 has been linked to the growth and progression of various cancers, including medulloblastoma. Inhibition of STAT3 has been shown to sensitize medulloblastoma cells to chemotherapy, leading to improved treatment outcomes. Different approaches to STAT3 inhibition have been developed, including small-molecule inhibitors and RNA interference. Preclinical studies have shown the efficacy of STAT3 inhibitors in medulloblastoma, and clinical trials are currently ongoing to evaluate their safety and effectiveness in patients with various solid tumors, including medulloblastoma. In addition, researchers are also exploring ways to optimize the use of STAT3 inhibitors in combination with chemotherapy and identify biomarkers that can predict treatment that will help to develop personalized treatment strategies. This review highlights the potential of selective inhibition of STAT3 as a novel approach for the treatment of medulloblastoma and suggests that further research into the development of STAT3 inhibitors could lead to improved outcomes for patients with aggressive cancer.

Research progress of multi-target HDAC inhibitors blocking the BRD4-LIFR-JAK1-STAT3 signaling pathway in the treatment of cancer

Histone deacetylase inhibitors (HDACis) show beneficial effects on different hematological malignancy subtypes. However, their impacts on treating solid tumors are still limited due to diverse resistance mechanisms. Recent studies have found that the feedback activation of BRD4-LIFR-JAK1-STAT3 pathway after HDACi incubation is a vital mechanism inducing resistance of specific solid tumor cells to HDACis. This review summarizes the recent development of multi-target HDACis that can concurrently block BRD4-LIFR-JAK1-STAT3 pathway. Moreover, our findings hope to shed novel lights on developing novel multi-target HDACis with reduced BRD4-LIFR-JAK1-STAT3-mediated drug resistance in some tumors.

Biomineralization-Tuned Nanounits Reprogram the Signal Transducer and Activator of Transcription 3 Signaling for Ferroptosis-Immunotherapy in Cancer Stem Cells

Cancer stem cells (CSCs) are promising targets for improving anticancer treatment outcomes while eliminating recurrence, but their treatment remains a major challenge. Here, we report a nanointegrative strategy to realize CSC-targeted ferroptosis-immunotherapy through spatiotemporally controlled reprogramming of STAT3-regulated signaling circuits. Specifically, STAT3 inhibitor niclosamide (Ni) and an experimental ferroptosis drug (1S, 3R)-RSL3 (RSL3) are integrated into hyaluronic acid-modified amorphous calcium phosphate (ACP) nanounits through biomineralization (CaP-PEG-HA@Ni/RSL3), which could be recognized by CD44-overexpressing CSCs and released in a synchronized manner. Ni inhibits the CSC-intrinsic STAT3-PD-L1 axis to stimulate adaptive immunity and enhance interferon gamma (IFNγ) secretion by CD8+ T cells to downregulate SLC7A11 and SLC3A2 for blocking glutathione biosynthesis. Meanwhile, Ni-dependent STAT3 inhibition also upregulates ACSL4 through downstream signaling and IFNγ feedback. These effects cooperate with RSL3-mediated GPX4 deactivation to induce pronounced ferroptosis. Furthermore, CaP-PEG-HA@Ni/RSL3 also impairs the immunosuppressive M2-like tumor-associated macrophages, while Ca2+ ions released from degraded ACP could chelate with lipid peroxides in ferroptotic CSCs to avoid CD8+ T-cell inhibition, thus boosting the effector function of activated CD8+ T cells. This study offers a cooperative ferroptosis-immunotherapeutic approach for the treatment of refractory cancer.

Baitouweng decoction suppresses growth of esophageal carcinoma cells through miR-495-3p/BUB1/STAT3 axis

BACKGROUND

Esophageal carcinoma (EC) is one of the most prevalent cancers in human populations worldwide. Baitouweng decoction is one of the most important Chinese medicine formulas, with the potential to treat cancer.

AIM

To investigate the role and mechanism of Baitouweng decoction on EC cells.

METHODS

Differentially expressed genes (DEGs) in EC tissues and normal tissues were screened by the cDNA microarray technique and by bioinformatics methods. The target genes of microRNAs were predicted based on the TargetScan database and verified by dual luciferase gene reporter assay. We used Baitouweng decoction to intervene EC cells, and detected the activity of EC9706 and KYSE150 cells by the MTT method. Cell cycle and apoptosis were measured by flow cytometry. The expression of BUB1 mRNA and miR-495-3p was measured by qRT-PCR. The protein levels of BUB1, STAT3, p-STAT3, CCNB1, CDK1, Bax, Caspase3, and Caspase9 were measured by Western blot analysis. The migration and invasion abilities of the cells were measured by wound-healing assay and Transwell invasion assay, respectively.

RESULTS

DEGs identified are involved in biological processes, signaling pathways, and network construction, which are mainly related to mitosis. BUB1 was the key hub gene, and it is also a target gene of miR-495-3p. Baitouweng decoction could upregulate miR-495-3p and inhibit BUB1 expression. In vitro experiments showed that Baitouweng decoction significantly inhibited the migration and invasion of EC cells and induced apoptosis and G2/M phase arrest. After treatment with Baitouweng decoction, the expression of Bax, Caspase 3, and Caspase 9 in EC cells increased significantly, while the expression of BUB1, CCNB1, and CDK1 decreased significantly. Moreover, the STAT3 signaling pathway may play an important role in this process.

CONCLUSION

Baitouweng decoction has a significant inhibitory effect on EC cell growth. BUB1 is a potential therapeutic target for EC. Further analysis showed that Baitouweng decoction may inhibit the growth of EC cells by upregulating miR-495-3p targeting the BUB1-mediated STAT3 signal pathway.

TET2-STAT3-CXCL5 nexus promotes neutrophil lipid transfer to fuel lung adeno-to-squamous transition

Phenotypic plasticity is a rising cancer hallmark, and lung adeno-to-squamous transition (AST) triggered by LKB1 inactivation is significantly associated with drug resistance. Mechanistic insights into AST are urgently needed to identify therapeutic vulnerability in LKB1-deficient lung cancer. Here, we find that ten-eleven translocation (TET)-mediated DNA demethylation is elevated during AST in KrasLSL-G12D/+; Lkb1L/L (KL) mice, and knockout of individual Tet genes reveals that Tet2 is required for squamous transition. TET2 promotes neutrophil infiltration through STAT3-mediated CXCL5 expression. Targeting the STAT3-CXCL5 nexus effectively inhibits squamous transition through reducing neutrophil infiltration. Interestingly, tumor-infiltrating neutrophils are laden with triglycerides and can transfer the lipid to tumor cells to promote cell proliferation and squamous transition. Pharmacological inhibition of macropinocytosis dramatically inhibits neutrophil-to-cancer cell lipid transfer and blocks squamous transition. These data uncover an epigenetic mechanism orchestrating phenotypic plasticity through regulating immune microenvironment and metabolic communication, and identify therapeutic strategies to inhibit AST.

Targeting STAT3 potentiates CDK4/6 inhibitors therapy in head and neck squamous cell carcinoma

Anti-CDK4/6 therapy has been employed for the treatment for head and neck squamous cell carcinoma (HNSCC) with CDK4/6 hyperactivation, but the response rate is relatively low. In this study, we first showed that CDK4 and CDK6 was over-expressed and conferred poor prognosis in HNSCC. Moreover, in RB-positive HNSCC, STAT3 signaling was activated induced by CDK4/6 inhibition and STAT3 promotes RB deficiency by upregulation of MYC. Thirdly, the combination of Stattic and CDK4/6 inhibitor results in striking anti-tumor effect in vitro and in Cal27 derived animal models. Additionally, phospho-STAT3 level negatively correlates with RB expression and predicts poor prognosis in patients with HNSCC. Taken together, our findings suggest an unrecognized function of STAT3 confers to CDK4/6 inhibitors resistance and presenting a promising combination strategy for patients with HNSCC.

Amino acid metabolic reprogramming in the tumor microenvironment and its implication for cancer therapy

Amino acids are essential building blocks for proteins, crucial energy sources for cell survival, and key signaling molecules supporting the resistant growth of tumor cells. In tumor cells, amino acid metabolic reprogramming is characterized by the enhanced uptake of amino acids as well as their aberrant synthesis, breakdown, and transport, leading to immune evasion and malignant progression of tumor cells. This article reviews the altered amino acid metabolism in tumor cells and its impact on tumor microenvironment, and also provides an overview of the current clinical applications of amino acid metabolism. Innovative drugs targeting amino acid metabolism hold great promise for precision and personalized cancer therapy.

Hawthorn with "homology of medicine and food": a review of anticancer effects and mechanisms

Over the past few years, there has been a gradual increase in the incidence of cancer, affecting individuals at younger ages. With its refractory nature and substantial fatality rate, cancer presents a notable peril to human existence and wellbeing. Hawthorn, a medicinal food homology plant belonging to the Crataegus genus in the Rosaceae family, holds great value in various applications. Due to its long history of medicinal use, notable effects, and high safety profile, hawthorn has garnered considerable attention and plays a crucial role in cancer treatment. Through the integration of modern network pharmacology technology and traditional Chinese medicine (TCM), a range of anticancer active ingredients in hawthorn have been predicted, identified, and analyzed. Studies have shown that ingredients such as vitexin, isoorientin, ursolic acid, and maslinic acid, along with hawthorn extracts, can effectively modulate cancer-related signaling pathways and manifest anticancer properties via diverse mechanisms. This review employs network pharmacology to excavate the potential anticancer properties of hawthorn. By systematically integrating literature across databases such as PubMed and CNKI, the review explores the bioactive ingredients with anticancer effects, underlying mechanisms and pathways, the synergistic effects of drug combinations, advancements in novel drug delivery systems, and ongoing clinical trials concerning hawthorn's anticancer properties. Furthermore, the review highlights the preventive health benefits of hawthorn in cancer prevention, offering valuable insights for clinical cancer treatment and the development of TCM with anticancer properties that can be used for both medicinal and edible purposes.

The Traces of Dysregulated lncRNAs-Associated ceRNA Axes in Retinoblastoma: A Systematic Scope Review

PURPOSE

Long non-coding RNAs are an essential component of competing endogenous RNA regulatory axes and play their role by sponging microRNAs and interfering with the regulation of gene expression. Because of the broadness of competing endogenous RNA interaction networks, they may help investigate treatment targets in complicated disorders.

METHODS

This study performed a systematic scoping review to assess verified loops of competing endogenous RNAs in retinoblastoma, emphasizing the competing endogenous RNAs axis related to long non-coding RNAs. We used a six-stage approach framework and the PRISMA guidelines. A systematic search of seven databases was done to locate suitable papers published before February 2022. Two reviewers worked independently to screen articles and collect data.

RESULTS

Out of 363 records, fifty-one articles met the inclusion criteria, and sixty-three axes were identified in desired articles. The majority of the research reported several long non-coding RNAs that were experimentally verified to act as competing endogenous RNAs in retinoblastoma: XIST/NEAT1/MALAT1/SNHG16/KCNQ1OT1, respectively. At the same time, around half of the studies investigated unique long non-coding RNAs.

CONCLUSIONS

Understanding the many features of this regulatory system may aid in elucidating the unknown etiology of Retinoblastoma and providing novel molecular targets for therapeutic and clinical applications.

STAT3 activation of SCAP-SREBP-1 signaling upregulates fatty acid synthesis to promote tumor growth

SCAP plays a central role in controlling lipid homeostasis by activating SREBP-1, a master transcription factor in controlling fatty acid (FA) synthesis. However, how SCAP expression is regulated in human cancer cells remains unknown. Here, we revealed that STAT3 binds to the promoter of SCAP to activate its expression across multiple cancer cell types. Moreover, we identified that STAT3 also concurrently interacts with the promoter of SREBF1 gene (encoding SREBP-1), amplifying its expression. This dual action by STAT3 collaboratively heightens FA synthesis. Pharmacological inhibition of STAT3 significantly reduces the levels of unsaturated FAs and phospholipids bearing unsaturated FA chains by reducing the SCAP-SREBP-1 signaling axis and its downstream effector SCD1. Examination of clinical samples from patients with glioblastoma, the most lethal brain tumor, demonstrates a substantial co-expression of STAT3, SCAP, SREBP-1, and SCD1. These findings unveil STAT3 directly regulates the expression of SCAP and SREBP-1 to promote FA synthesis, ultimately fueling tumor progression.

Asymmetric post-translational modifications regulate the nuclear translocation of STAT3 homodimers in response to leukemia inhibitory factor

STAT3 is a pleiotropic transcription factor overactivated in 70% of solid tumours. We have recently reported that inactivating mutations on residues susceptible to post-translational modifications (PTMs) in only one of the monomers (i.e. asymmetric) caused changes in the cellular distribution of STAT3 homodimers. Here, we used more controlled experimental conditions, i.e. without the interference of endogenous STAT3 (STAT3-/- HeLa cells) and in the presence of a defined cytokine stimulus (Leukemia Inhibitory Factor, LIF), to provide further evidence that asymmetric PTMs affect the nuclear translocation of STAT3 homodimers. Time-lapse microscopy for 20 min after LIF stimulation showed that S727 dephosphorylation (S727A) and K685 inactivation (K685R) slightly enhanced the nuclear translocation of STAT3 homodimers, while K49 inactivation (K49R) delayed STAT3 nuclear translocation. Our findings suggest that asymmetrically modified STAT3 homodimers could be a new level of STAT3 regulation and, therefore, a potential target for cancer therapy.

A novel function of STAT3β in suppressing interferon response improves outcome in acute myeloid leukemia

Signal transducer and activator of transcription 3 (STAT3) is frequently overexpressed in patients with acute myeloid leukemia (AML). STAT3 exists in two distinct alternatively spliced isoforms, the full-length isoform STAT3α and the C-terminally truncated isoform STAT3β. While STAT3α is predominantly described as an oncogenic driver, STAT3β has been suggested to act as a tumor suppressor. To elucidate the role of STAT3β in AML, we established a mouse model of STAT3β-deficient, MLL-AF9-driven AML. STAT3β deficiency significantly shortened survival of leukemic mice confirming its role as a tumor suppressor. Furthermore, RNA sequencing revealed enhanced STAT1 expression and interferon (IFN) signaling upon loss of STAT3β. Accordingly, STAT3β-deficient leukemia cells displayed enhanced sensitivity to blockade of IFN signaling through both an IFNAR1 blocking antibody and the JAK1/2 inhibitor Ruxolitinib. Analysis of human AML patient samples confirmed that elevated expression of IFN-inducible genes correlated with poor overall survival and low STAT3β expression. Together, our data corroborate the tumor suppressive role of STAT3β in a mouse model in vivo. Moreover, they provide evidence that its tumor suppressive function is linked to repression of the STAT1-mediated IFN response. These findings suggest that the STAT3β/α mRNA ratio is a significant prognostic marker in AML and holds crucial information for targeted treatment approaches. Patients displaying a low STAT3β/α mRNA ratio and unfavorable prognosis could benefit from therapeutic interventions directed at STAT1/IFN signaling.

PRMT5-mediated methylation of STAT3 is required for lung cancer stem cell maintenance and tumour growth

STAT3 is constitutively activated in many cancer types, including lung cancer, and can induce cancer cell proliferation and cancer stem cell (CSC) maintenance. STAT3 is activated by tyrosine kinases, such as JAK and SRC, but the mechanism by which STAT3 maintains its activated state in cancer cells remains unclear. Here, we show that PRMT5 directly methylates STAT3 and enhances its activated tyrosine phosphorylation in non-small cell lung cancer (NSCLC) cells. PRMT5 expression is also induced by STAT3, suggesting the presence of a positive feedback loop in cancer cells. Furthermore, methylation of STAT3 at arginine 609 by PRMT5 is important for its transcriptional activity and support of tumour growth and CSC maintenance. Indeed, NSCLC cells expressing the STAT3 mutant which R609 was replaced to alanine (R609K) show significantly impaired tumour growth in nude mice. Overall, our study reveals a mechanism by which STAT3 remains activated in NSCLC and provides a new target for cancer therapeutic approaches.

Update on the development of TGR5 agonists for human diseases

The G protein-coupled bile acid receptor 1 (GPBAR1) or TGR5 is widely distributed across organs, including the small intestine, stomach, liver, spleen, and gallbladder. Many studies have established strong correlations between TGR5 and glucose homeostasis, energy metabolism, immune-inflammatory responses, and gastrointestinal functions. These results indicate that TGR5 has a significant impact on the progression of tumor development and metabolic disorders such as diabetes mellitus and obesity. Targeting TGR5 represents an encouraging therapeutic approach for treating associated human ailments. Notably, the GLP-1 receptor has shown exceptional efficacy in clinical settings for diabetes management and weight loss promotion. Currently, numerous TGR5 agonists have been identified through natural product-based approaches and virtual screening methods, with some successfully progressing to clinical trials. This review summarizes the intricate relationships between TGR5 and various diseases emphasizing recent advancements in research on TGR5 agonists, including their structural characteristics, design tactics, and biological activities. We anticipate that this meticulous review could facilitate the expedited discovery and optimization of novel TGR5 agonists.

A Natural Peptide from A Traditional Chinese Medicine Has the Potential to Treat Chronic Atrophic Gastritis by Activating Gastric Stem Cells

Chronic atrophic gastritis (AG) is initiated mainly by Helicobacter pylori infection, which may progress to stomach cancer following the Correa's cascade. The current treatment regimen is H. pylori eradication, yet evidence is lacking that this treatment is effective on later stages of AG especially gastric gland atrophy. Here, using AG mouse model, patient samples, gastric organoids, and lineage tracing, this study unraveled gastric stem cell (GSC) defect as a crucial pathogenic factor in AG in mouse and human. Moreover, a natural peptide is isolated from a traditional Chinese medicine that activated GSCs to regenerate gastric epithelia in experimental AG models and revitalized the atrophic gastric organoids derived from patients. It is further shown that the peptide exerts its functions by stabilizing the EGF-EGFR complex and specifically activating the downstream ERK and Stat1 signaling. Overall, these findings advance the understanding of AG pathogenesis and open a new avenue for AG treatment.

Stat3 Regulates Developmental Hematopoiesis and Impacts Myeloid Cell Function via Canonical and Non-Canonical Modalities

INTRODUCTION

Signal transducer and activator of transcription (STAT) 3 is extensively involved in the development, homeostasis, and function of immune cells, with STAT3 disruption associated with human immune-related disorders. The roles ascribed to STAT3 have been assumed to be due to its canonical mode of action as an inducible transcription factor downstream of multiple cytokines, although alternative noncanonical functional modalities have also been identified. The relative involvement of each mode was further explored in relevant zebrafish models.

METHODS

Genome editing with CRISPR/Cas9 was used to generate mutants of the conserved zebrafish Stat3 protein: a loss of function knockout (KO) mutant and a mutant lacking C-terminal sequences including the transactivation domain (ΔTAD). Lines harboring these mutations were analyzed with respect to blood and immune cell development and function in comparison to wild-type zebrafish.

RESULTS

The Stat3 KO mutant showed perturbation of hematopoietic lineages throughout primitive and early definitive hematopoiesis. Neutrophil numbers did not increase in response to lipopolysaccharide (LPS) or granulocyte colony-stimulating factor (G-CSF) and their migration was significantly diminished, the latter correlating with abrogation of the Cxcl8b/Cxcr2 pathway, with macrophage responses perturbed. Intriguingly, many of these phenotypes were not shared by the Stat3 ΔTAD mutant. Indeed, only neutrophil and macrophage development were disrupted in these mutants with responsiveness to LPS and G-CSF maintained, and neutrophil migration actually increased.

CONCLUSION

This study has identified roles for zebrafish Stat3 within hematopoietic stem cells impacting multiple lineages throughout primitive and early definitive hematopoiesis, myeloid cell responses to G-CSF and LPS and neutrophil migration. Many of these roles showed conservation, but notably several involved noncanonical modalities, providing additional insights for relevant diseases.

Zeolitic imidazolate framework-8: a versatile nanoplatform for tissue regeneration

Extensive research on zeolitic imidazolate framework (ZIF-8) and its derivatives has highlighted their unique properties in nanomedicine. ZIF-8 exhibits advantages such as pH-responsive dissolution, easy surface functionalization, and efficient drug loading, making it an ideal nanosystem for intelligent drug delivery and phototherapy. These characteristics have sparked significant interest in its potential applications in tissue regeneration, particularly in bone, skin, and nerve regeneration. This review provides a comprehensive assessment of ZIF-8's feasibility in tissue engineering, encompassing material synthesis, performance testing, and the development of multifunctional nanosystems. Furthermore, the latest advancements in the field, as well as potential limitations and future prospects, are discussed. Overall, this review emphasizes the latest developments in ZIF-8 in tissue engineering and highlights the potential of its multifunctional nanoplatforms for effective complex tissue repair.

STAT3 is a genetic modifier of TGF-beta induced EMT in KRAS mutant pancreatic cancer

Oncogenic mutations in KRAS are among the most common in cancer. Classical models suggest that loss of epithelial characteristics and the acquisition of mesenchymal traits are associated with cancer aggressiveness and therapy resistance. However, the mechanistic link between these phenotypes and mutant KRAS biology remains to be established. Here, we identify STAT3 as a genetic modifier of TGF-beta-induced epithelial to mesenchymal transition. Gene expression profiling of pancreatic cancer cells identifies more than 200 genes commonly regulated by STAT3 and oncogenic KRAS. Functional classification of the STAT3-responsive program reveals its major role in tumor maintenance and epithelial homeostasis. The signatures of STAT3-activated cell states can be projected onto human KRAS mutant tumors, suggesting that they faithfully reflect characteristics of human disease. These observations have implications for therapeutic intervention and tumor aggressiveness.

Discovery of the Highly Selective and Potent STAT3 Inhibitor for Pancreatic Cancer Treatment

Signal transducer and activator of transcription 3 (STAT3) is an attractive cancer therapeutic target. Unfortunately, targeting STAT3 with small molecules has proven to be very challenging, and for full activation of STAT3, the cooperative phosphorylation of both tyrosine 705 (Tyr705) and serine 727 (Ser727) is needed. Further, a selective inhibitor of STAT3 dual phosphorylation has not been developed. Here, we identified a low nanomolar potency and highly selective small-molecule STAT3 inhibitor that simultaneously inhibits both STAT3 Tyr705 and Ser727 phosphorylation. YY002 potently inhibited STAT3-dependent tumor cell growth in vitro and achieved potent suppression of tumor growth and metastasis in vivo. More importantly, YY002 exhibited favorable pharmacokinetics, an acceptable safety profile, and superior antitumor efficacy compared to BBI608 (STAT3 inhibitor that has advanced into phase III trials). For the mechanism, YY002 is selectively bound to the STAT3 Src Homology 2 (SH2) domain over other STAT members, which strongly suppressed STAT3 nuclear and mitochondrial functions in STAT3-dependent cells. Collectively, this study suggests the potential of small-molecule STAT3 inhibitors as possible anticancer therapeutic agents.

RSK4 promotes the macrophage recruitment and M2 polarization in esophageal squamous cell carcinoma

High infiltration of tumor-associated macrophages (TAMs) participates in host immunity and tumor progression in patients with esophageal squamous cell carcinoma (ESCC). Ribosomal s6 kinase 4 (RSK4) has been shown to be aberrantly overexpressed in ESCC. The role of RSK4 in cytokine secretion and its impact on macrophage recruitment and M2 polarization remains unclear. Therefore, a thorough understanding of RSK4 is needed to expand our knowledge of its therapeutic potential. Herein, RSK4 expression in human ESCC tissues and a xenograft mouse model was positively correlated with high infiltration of M0 and M2 macrophages which is positively associated with unfavorable overall survival outcomes and treatment resistance in patients with ESCC. In vitro experiments revealed that RSK4 derived from ESCC cells promoted macrophage recruitment and M2 polarization by enhancingsoluble intercellular adhesion molecule-1 (sICAM-1) secretion via direct and indirect STAT3 phosphorylation. Furthermore, RSK4-induced macrophages enhanced tumor proliferation, migration, and invasion by secreting C-C motif chemokine ligand 22 (CCL22). We further showed that patients with elevated CD68 and CD206 expression had unfavorable overall survival. Collectively, these results demonstrate that RSK4 promotes the macrophage recruitment and M2 polarization by regulating the STAT3/ICAM-1 axis in ESCC, influencing tumor progression primarily in a CCL22-dependent manner. These data also offer valuable insights for developing novel agents for the treatment of ESCC.

JAK/STAT3 represents a therapeutic target for colorectal cancer patients with stromal-rich tumors

Colorectal cancer (CRC) is a heterogenous malignancy underpinned by dysregulation of cellular signaling pathways. Previous literature has implicated aberrant JAK/STAT3 signal transduction in the development and progression of solid tumors. In this study we investigate the effectiveness of inhibiting JAK/STAT3 in diverse CRC models, establish in which contexts high pathway expression is prognostic and perform in depth analysis underlying phenotypes. In this study we investigated the use of JAK inhibitors for anti-cancer activity in CRC cell lines, mouse model organoids and patient-derived organoids. Immunohistochemical staining of the TransSCOT clinical trial cohort, and 2 independent large retrospective CRC patient cohorts was performed to assess the prognostic value of JAK/STAT3 expression. We performed mutational profiling, bulk RNASeq and NanoString GeoMx® spatial transcriptomics to unravel the underlying biology of aberrant signaling. Inhibition of signal transduction with JAK1/2 but not JAK2/3 inhibitors reduced cell viability in CRC cell lines, mouse, and patient derived organoids (PDOs). In PDOs, reduced Ki67 expression was observed post-treatment. A highly significant association between high JAK/STAT3 expression within tumor cells and reduced cancer-specific survival in patients with high stromal invasion (TSPhigh) was identified across 3 independent CRC patient cohorts, including the TrasnSCOT clinical trial cohort. Patients with high phosphorylated STAT3 (pSTAT3) within the TSPhigh group had higher influx of CD66b + cells and higher tumoral expression of PDL1. Bulk RNAseq of full section tumors showed enrichment of NFκB signaling and hypoxia in these cases. Spatial deconvolution through GeoMx® demonstrated higher expression of checkpoint and hypoxia-associated genes in the tumor (pan-cytokeratin positive) regions, and reduced lymphocyte receptor signaling in the TME (pan-cytokeratin- and αSMA-) and αSMA (pan-cytokeratin- and αSMA +) areas. Non-classical fibroblast signatures were detected across αSMA + regions in cases with high pSTAT3. Therefore, in this study we have shown that inhibition of JAK/STAT3 represents a promising therapeutic strategy for patients with stromal-rich CRC tumors. High expression of JAK/STAT3 proteins within both tumor and stromal cells predicts poor outcomes in CRC, and aberrant signaling is associated with distinct spatially-dependant differential gene expression.

Development of Platinum Complexes for Tumor Chemoimmunotherapy

Platinum complexes are potential antitumor drugs in chemotherapy. Their impact on tumor treatment could be greatly strengthened by combining with immunotherapy. Increasing evidences indicate that the antitumor activity of platinum complexes is not limited to chemical killing effects, but also extends to immunomodulatory actions. This review introduced the general concept of chemoimmunotherapy and summarized the progress of platinum complexes as chemoimmunotherapeutic agents in recent years. Platinum complexes could be developed into inducers of immunogenic cell death, blockers of immune checkpoint, regulators of immune signaling pathway, and modulators of tumor immune microenvironment, etc. The synergy between chemotherapeutic and immunomodulatory effects reinforces the antitumor activity of platinum complexes, and helps them circumvent the drug resistance and systemic toxicity. The exploration of platinum complexes for chemoimmunotherapy may create new opportunities to revive the discovery of metal anticancer drugs.

IL-8 activates fibroblasts to promote the invasion of HNSCC cells via STAT3-MMP1

Matrix metalloproteinase-1 (MMP1) has an aberrant expression relevant to various behaviors of cancers. As dominant components of the tumor stroma, fibroblasts constitute an important source of Matrix metalloproteinase (MMPs) including mainly MMP1. The impacts of MMP1 derived from fibroblasts in tumor microenvironment, however, is not well defined. In this study, we demonstrated a part of crosstalk between fibroblasts and cancer cells that enhanced the invasiveness of cancer cells, IL8-induced activation of STAT3 signaling pathway as a key promoter to elevated MMP1 level in fibroblasts that supports the migration and invasion of head and neck squamous cell carcinoma (HNSCC) cells by extracellular matrix degradation. Importantly, once exposed to the inhibitor of STAT3 phosphorylation (TPCA-1), the enhanced induction of HNSCC cells invasion triggered by fibroblasts was significantly impaired.

Cyclometalated iridium(III) complexes as anti-breast cancer and anti-metastasis agents via STAT3 inhibition

Breast cancer is the most commonly diagnosed cancer and second‑leading cause of cancer deaths in women. Signal transducer and activator of transcription 3 (STAT3) plays a critical role in promoting breast cancer cell proliferation, invasion, angiogenesis, and metastasis, and the high expression of STAT3 is related to the occurrence and poor chemotherapy sensitivity of breast cancer. Iridium(III) complexes Ir-PTS-1- 4 containing a pterostilbene-derived ligand were synthesized to inhibit the STAT3 pathway in breast cancer. Ir-PTS-4 inhibited the proliferation of breast cancer cells by suppressing the expression of phosphorylated STAT3 and STAT3-related cyclin D1, arresting cell cycle in the S-phase, inducing DNA damage and reactive oxygen species (ROS) generation, eventually leading to autophagic cell death. The cell metastasis and invasion were also inhibited after Ir-PTS-4 treatment. Besides, Ir-PTS-4 exhibited excellent anti-proliferation activity in 3D multicellular tumor spheroids, showing potential for the treatment of solid tumors. This work presents the rational design of metal-based anticancer agents to block the STAT3 pathway for simultaneously inhibiting breast cancer proliferation and metastasis.

Network pharmacology study to explore the multiple molecular mechanism of SH003 in the treatment of non-small cell lung cancer

BACKGROUND

Non-small cell lung cancer (NSCLC) is one of the leading causes of human death worldwide. Herbal prescription SH003 has been developed to treat several cancers including NSCLC. Due to the multi-component nature of SH003 with multiple targets and pathways, a network pharmacology study was conducted to analyze its active compounds, potential targets, and pathways for the treatment of NSCLC.

METHODS

We systematically identified oral active compounds within SH003, employing ADME criteria-based screening from TM-MC, OASIS, and TCMSP databases. Concurrently, SH003-related and NSCLC-associated targets were amalgamated from various databases. Overlapping targets were deemed anti-NSCLC entities of SH003. Protein-protein interaction networks were constructed using the STRING database, allowing the identification of pivotal proteins through node centrality measures. Empirical validation was pursued through LC-MS analysis of active compounds. Additionally, in vitro experiments, such as MTT cell viability assays and western blot analyses, were conducted to corroborate network pharmacology findings.

RESULTS

We discerned 20 oral active compounds within SH003 and identified 239 core targets shared between SH003 and NSCLC-related genes. Network analyses spotlighted 79 hub genes, including TP53, JUN, AKT1, STAT3, and MAPK3, crucial in NSCLC treatment. GO and KEGG analyses underscored SH003's multifaceted anti-NSCLC effects from a genetic perspective. Experimental validations verified SH003's impact on NSCLC cell viability and the downregulation of hub genes. LC-MS analysis confirmed the presence of four active compounds, namely hispidulin, luteolin, baicalein, and chrysoeriol, among the eight compounds with a median of > 10 degrees in the herb-compounds-targets network in SH003. Previously unidentified targets like CASP9, MAPK9, and MCL1 were unveiled, supported by existing NSCLC literature, enhancing the pivotal role of empirical validation in network pharmacology.

CONCLUSION

Our study pioneers the harmonization of theoretical predictions with practical validations. Empirical validation illuminates specific SH003 compounds within NSCLC, simultaneously uncovering novel targets for NSCLC treatment. This integrated strategy, accentuating empirical validation, establishes a paradigm for in-depth herbal medicine exploration. Furthermore, our network pharmacology study unveils fresh insights into SH003's multifaceted molecular mechanisms combating NSCLC. Through this approach, we delineate active compounds of SH003 and target pathways, reshaping our understanding of its therapeutic mechanisms in NSCLC treatment.

AKT2S128/CCTαS315/319/323-positive cancer-associated fibroblasts (CAFs) mediate focal adhesion kinase (FAK) inhibitors resistance via secreting phosphatidylcholines (PCs)

Abnormal metabolism is regarded as an oncogenic hallmark related to tumor progression and therapeutic resistance. Present study employed multi-omics, including phosphoproteomics, untargeted metabolomics and lipidomics, to demonstrate that the pAKT2 Ser128 and pCCTα Ser315/319/323-positive cancer-associated fibroblasts (CAFs) substantially release phosphatidylcholines (PCs), contributing to the resistance of focal adhesion kinase (FAK) inhibitors in esophageal squamous cell carcinoma (ESCC) treatment. Additionally, we observed extremely low levels of FAK Tyr397 expression in CAFs, potentially offering no available target for FAK inhibitors playing their anti-growth role in CAFs. Consequently, FAK inhibitor increased the intracellular concentration of Ca2+ in CAFs, promoting the formation of AKT2/CCTα complex, leading to phosphorylation of CCTα Ser315/319/323 sites and eventually enhancing stromal PC production. This activation could stimulate the intratumoral Janus kinase 2 (JAK2)/Signal transducer and activator of transcription 3 (STAT3) pathway, triggering resistance to FAK inhibition. Analysis of clinical samples demonstrated that stromal pAKT2 Ser128 and pCCTα Ser315/319/323 are related to the tumor malignancy and reduced patient survival. Pseudo-targeted lipidomics and further validation cohort quantitatively showed that plasma PCs enable to distinguish the malignant extent of ESCC patients. In conclusion, inhibition of stroma-derived PCs and related pathway could be possible therapeutic strategies for tumor therapy.

STAT3 Decoy Oligodeoxynucleotides Suppress Liver Inflammation and Fibrosis in Liver Cancer Cells and a DDC-Induced Liver Injury Mouse Model

Liver damage caused by various factors results in fibrosis and inflammation, leading to cirrhosis and cancer. Fibrosis results in the accumulation of extracellular matrix components. The role of STAT proteins in mediating liver inflammation and fibrosis has been well documented; however, approved therapies targeting STAT3 inhibition against liver disease are lacking. This study investigated the anti-fibrotic and anti-inflammatory effects of STAT3 decoy oligodeoxynucleotides (ODN) in hepatocytes and liver fibrosis mouse models. STAT3 decoy ODN were delivered into cells using liposomes and hydrodynamic tail vein injection into 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC)-fed mice in which liver injury was induced. STAT3 target gene expression changes were verified using qPCR and Western blotting. Liver tissue fibrosis and bile duct proliferation were assessed in animal experiments using staining techniques, and macrophage and inflammatory cytokine distribution was verified using immunohistochemistry. STAT3 decoy ODN reduced fibrosis and inflammatory factors in liver cancer cell lines and DDC-induced liver injury mouse model. These results suggest that STAT3 decoy ODN may effectively treat liver fibrosis and must be clinically investigated.

Unraveling the complexity of STAT3 in cancer: molecular understanding and drug discovery

Signal transducer and activator of transcription 3 (STAT3) is a transcriptional factor involved in almost all cancer hallmark features including tumor proliferation, metastasis, angiogenesis, immunosuppression, tumor inflammation, metabolism reprogramming, drug resistance, cancer stemness. Therefore, STAT3 has become a promising therapeutic target in a wide range of cancers. This review focuses on the up-to-date knowledge of STAT3 signaling in cancer. We summarize both the positive and negative modulators of STAT3 together with the cancer hallmarks involving activities regulated by STAT3 and highlight its extremely sophisticated regulation on immunosuppression in tumor microenvironment and metabolic reprogramming. Direct and indirect inhibitors of STAT3 in preclinical and clinical studies also have been summarized and discussed. Additionally, we highlight and propose new strategies of targeting STAT3 and STAT3-based combinations with established chemotherapy, targeted therapy, immunotherapy and combination therapy. These efforts may provide new perspectives for STAT3-based target therapy in cancer.

Inhibiting anti-angiogenic VEGF165b activates a miR-17-20a-Calcipressin-3 pathway that revascularizes ischemic muscle in peripheral artery disease

BACKGROUND

VEGF165a increases the expression of the microRNA-17-92 cluster, promoting developmental, retinal, and tumor angiogenesis. We have previously shown that VEGF165b, an alternatively spliced anti-angiogenic VEGF-A isoform, inhibits the VEGFR-STAT3 pathway in ischemic endothelial cells (ECs) to decrease their angiogenic capacity. In ischemic macrophages (Møs), VEGF165b inhibits VEGFR1 to induce S100A8/A9 expression, which drives M1-like polarization. Our current study aims to determine whether VEGF165b inhibition promotes perfusion recovery by regulating the microRNA(miR)-17-92 cluster in preclinical PAD.

METHODS

Femoral artery ligation and resection was used as a preclinical PAD model. Hypoxia serum starvation (HSS) was used as an in vitro PAD model. VEGF165b was inhibited/neutralized by an isoform-specific VEGF165b antibody.

RESULTS

Here, we show that VEGF165b-inhibition induces the expression of miR-17-20a (within miR-17-92 (miR-17-18a-19a-19b-20a-92) cluster) in HSS-ECs and HSS-Møs vs. respective normal and/or isotype-matched IgG controls to enhance perfusion recovery. Consistent with the bioinformatics analysis that revealed RCAN3 as a common target of miR-17 and miR-20a, Argonaute-2 pull-down assays showed decreased miR-17-20a expression and higher RCAN3 expression in the RNA-induced silencing complex of HSS-ECs and HSS-Møs vs. respective controls. Inhibiting miR-17-20a induced RCAN3 levels to decrease ischemic angiogenesis and promoted M1-like polarization to impair perfusion recovery. Finally, using STAT3 inhibitors, S100A8/A9 silencers, and VEGFR1-deficient ECs and Møs, we show that VEGF165b-inhibition activates the miR-17-20a-RCAN3 pathway independent of VEGFR1-STAT3 or VEGFR1-S100A8/A9 in ischemic-ECs and ischemic-Møs respectively.

CONCLUSIONS

Our data revealed a hereunto unrecognized therapeutic 'miR-17-20a-RCAN3' pathway in the ischemic vasculature that is VEGFR1-STAT3/S100A8/A9 independent and is activated only upon VEGF165b-inhibition in PAD.

Zinc finger protein 831 promotes apoptosis and enhances chemosensitivity in breast cancer by acting as a novel transcriptional repressor targeting the STAT3/Bcl2 signaling pathway

Emerging evidence suggested that zinc finger protein 831 (ZNF831) was associated with immune activity and stem cell regulation in breast cancer. Whereas, the roles and molecular mechanisms of ZNF831 in oncogenesis remain unclear. ZNF831 expression was significantly diminished in breast cancer which was associated with promoter CpG methylation but not mutation. Ectopic over-expression of ZNF831 suppressed breast cancer cell proliferation and colony formation and promoted apoptosis in vitro, while knockdown of ZNF831 resulted in an opposite phenotype. Anti-proliferation effect of ZNF831 was verified in vivo. Bioinformatic analysis of public databases and transcriptome sequencing both showed that ZNF831 could enhance apoptosis through transcriptional regulation of the JAK/STAT pathway. ChIP and luciferase report assays demonstrated that ZNF831 could directly bind to one specific region of STAT3 promoter and induce the transcriptional inhibition of STAT3. As a result, the attenuation of STAT3 led to a restraint of the transcription of Bcl2 and thus accelerated the apoptotic progression. Augmentation of STAT3 diminished the apoptosis-promoting effect of ZNF831 in breast cancer cell lines. Furthermore, ZNF831 could ameliorate the anti-proliferation effect of capecitabine and gemcitabine in breast cancer cell lines. Our findings demonstrate for the first time that ZNF831 is a novel transcriptional suppressor through inhibiting the expression of STAT3/Bcl2 and promoting the apoptosis process in breast cancer, suggesting ZNF831 as a novel biomarker and potential therapeutic target for breast cancer patients.

Long noncoding RNA H19 in ovarian biology and placenta development

As the first long noncoding RNA to be discovered, H19 has gained substantial attention as a key regulator of several biological processes and its roles in female reproductive biology are gradually getting revealed. Herein, we have summarized the current evidence regarding H19 expression pattern and involvement in the developmental and pathological processes associated with the ovary and the placenta. The findings indicate that within the ovaries, H19 is expressed in the antral and cystic atretic follicles as well as in the corpora lutea but absent in the primordial, primary, and secondary follicles. Its normal expression promotes the maturation of antral follicles and prevents their premature selection for the ovulatory journey while its aberrant induction promotes polycystic ovary syndrome development and ovarian cancer metastasis. In the placenta, H19 is highly expressed in the cytotrophoblasts and extravillous trophoblasts but weakly expressed in the syncytiotrophoblast layer and potentially controls trophoblast cell fate decisions during placenta development. Abnormal expression of H19 is observed in the placental villi of pregnancies affected by pre-eclampsia and fetal growth restriction. Therefore, dysregulated H19 is a candidate biomarker and therapeutic target for the mitigation of ovarian and placenta-associated diseases.

Integrated transcriptomic and proteomic analysis reveals Guizhi-Fuling Wan inhibiting STAT3-EMT in ovarian cancer progression

BACKGROUND

Ovarian cancer (OC) is the most lethal gynecological malignancy. Frequent peritoneal dissemination is the main cause of low survival rate. Guizhi-Fuling Wan (GZFL) is a classical traditional Chinese herbal formula that has been clinically used for treating ovarian cancer with good outcome. However, its therapeutic mechanism for treating OC has not been clearly elucidated.

PURPOSE

We aim to elucidate the potential mechanisms of GZFL in treating OC with a focus on STAT3 signaling pathway.

METHODS

In vivo efficacy of GZFL was assessed using an OC xenograft mouse model. Proteomics analysis in OC cells and RNA-seq analysis in mice tumors were performed to fully capture the translational and transcriptional signature of GZFL. Effects of GZFL on proliferation, spheroid formation and reactive oxygen species (ROS) were assessed using wildtype and STAT3 knockout OC cells in vitro. STAT3 activation and transcription activity, hypoxia and EMT-related protein expression were assessed to validate the biological activity of GZFL.

RESULTS

GZFL suppresses tumor growth with a safety profile in mice, while prevents cell growth, spheroid formation and accumulates ROS in a STAT3-dependent manner in vitro. GZFL transcriptionally and translationally affects genes involved in inflammatory signaling, EMT, cell migration, and cellular hypoxic stress response. In depth molecular study confirmed that GZFL-induced cytotoxicity and EMT suppression in OC cells are directly corelated to inhibition of STAT3 activation and transcription activity.

CONCLUSION

Our study provides the first evidence that GZFL inhibits OC progression through suppressing STAT3-EMT signaling. These results will further support its potential clinical use in OC.

IL20RB signaling enhances stemness and chemotherapy resistance in pancreatic cancer

OBJECTIVE

Pancreatic cancer is an aggressive malignancy with high mortality, and cancer cell stemness and related drug resistance are considered important contributors to its poor prognosis. The objective of this study was to identify regulatory targets associated with the maintenance of pancreatic cancer stemness.

MATERIALS AND METHODS

Pancreatic tumor samples were collected from patients at Sun Yat-sen University Cancer Center, followed by immunofluorescence analysis. Pancreatic cancer cell lines with Interleukin-20 receptor subunit beta (IL20RB) overexpression and knockdown were established, and clonal formation, spheroid formation and side population cell analysis were conducted. The effects of IL20RB knockdown on the tumor-forming ability of pancreatic cancer cells and chemotherapy resistance in vivo were explored.

RESULTS

IL20RB expression was significantly upregulated in pancreatic cancer tissues, and was correlated with unfavorable prognosis. The IL20RB receptor promotes stemness and chemoresistance in both in vitro and in vivo models of pancreatic cancer. Mechanistically, IL20RB enhances the stemness and chemoresistance of pancreatic cancer by promoting STAT3 phosphorylation, an effect that can be counteracted by a STAT3 phosphorylation inhibitors. Additionally, Interleukin-19 derived from the microenvironment is identified as the primary ligand for IL20RB in mediating these effects.

CONCLUSION

Our findings demonstrate that IL20RB plays a crucial role in promoting stemness in pancreatic cancer. This discovery provides a potential therapeutic target for this lethal disease.

New perspectives in cancer immunotherapy: targeting IL-6 cytokine family

Chronic inflammation has been recognized as a canonical cancer hallmark. It is orchestrated by cytokines, which are master regulators of the tumor microenvironment (TME) as they represent the main communication bridge between cancer cells, the tumor stroma, and the immune system. Interleukin (IL)-6 represents a keystone cytokine in the link between inflammation and cancer. Many cytokines from the IL-6 family, which includes IL-6, oncostatin M, leukemia inhibitory factor, IL-11, IL-27, IL-31, ciliary neurotrophic factor, cardiotrophin 1, and cardiotrophin-like cytokine factor 1, have been shown to elicit tumor-promoting roles by modulating the TME, making them attractive therapeutic targets for cancer treatment.The development of immune checkpoint blockade (ICB) immunotherapies has radically changed the outcome of some cancers including melanoma, lung, and renal, although not without hurdles. However, ICB shows limited efficacy in other solid tumors. Recent reports support that chronic inflammation and IL-6 cytokine signaling are involved in resistance to immunotherapy. This review summarizes the available preclinical and clinical data regarding the implication of IL-6-related cytokines in regulating the immune TME and the response to ICB. Moreover, the potential clinical benefit of combining ICB with therapies targeting IL-6 cytokine members for cancer treatment is discussed.

JAK/STAT signaling and cellular iron metabolism in hepatocellular carcinoma: therapeutic implications

Iron metabolism plays a crucial role in the development and progression of hepatocellular carcinoma (HCC), the most common type of primary liver cancer. Iron is an essential micronutrient that is involved in many physiological processes, including oxygen transport, DNA synthesis, and cellular growth and differentiation. However, excessive iron accumulation in the liver has been linked to oxidative stress, inflammation, and DNA damage, which can increase the risk of HCC. Studies have shown that iron overload is common in patients with HCC and that it is associated with a poor prognosis and reduced survival rates. Various iron metabolism-related proteins and signaling pathways such as the JAK/STAT pathway are dysregulated in HCC. Moreover, reduced hepcidin expression was reported to promote HCC in a JAK/STAT pathway-dependent manner. Therefore, it is important to understand the crosstalk between iron metabolism and the JAK/STAT pathway to prevent or treat iron overload in HCC. Iron chelators can bind to iron and remove it from the body, but its effect on JAK/STAT pathway is unclear. Also, HCC can be targeted by using the JAK/STAT pathway inhibitors, but their effect on hepatic iron metabolism is not known. In this review, for the first time, we focus on the role of the JAK/STAT signaling pathway in regulating cellular iron metabolism and its association with the development of HCC. We also discuss novel pharmacological agents and their therapeutic potential in manipulating iron metabolism and JAK/STAT signaling in HCC.

Zwitterionic polymer on silicone implants inhibits the bacteria-driven pathogenic mechanism and progress of breast implant-associated anaplastic large cell lymphoma

Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) occurs in the capsule surrounding breast implants. Malignant transformation of T cells by bacteria-driven chronic inflammation may be underlying BIA-ALCL mechanism. Here, we covalently grafted 2-methacryloyloxyethyl phosphorylcholine (MPC)-based polymers on a silicone surface and examined its effects against BIA-ALCL pathogenesis. MPC grafting strongly inhibited the adhesion of bacteria and bacteria-causing inflammation. Additionally, cancer T cell proliferation and capsule-derived fibroblast-cancer cell communication were effectively inhibited by MPC grafting. We further demonstrated the effect of MPC against the immune responses causing BIA-ALCL around human silicone implants in micro-pigs. Finally, we generated a xenograft anaplastic T cell lymphoma mouse model around the silicone implants and demonstrated that MPC grafting could effectively inhibit the lymphoma progression. This study is the first to show that bacteria-driven induction and progression of BIA-ALCL can be effectively inhibited by surface modification of implants. STATEMENT OF SIGNIFICANCE: Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is a major concern in the field of plastic and reconstructive surgery. In this study, we demonstrate strong inhibitory effect of zwitterionic polymer grafting on BIA-ALCL pathogenesis and progression, induced by bacterial infection and inflammation, both in vitro and in vivo. This study provides a molecular basis for the development of novel breast implants that can prevent various potential complications such as excessive capsular contracture, breast implant illness, and BIA-ALCL incidence, as well as for expanding the biomedical applications of zwitterionic polymers.

Methoxyhispolon Methyl Ether, a Hispolon Analog, Thwarts the SRC/STAT3/BCL-2 Axis to Provoke Human Triple-Negative Breast Cancer Cell Apoptosis In Vitro

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer with few treatment options. A promising TNBC treatment approach is targeting the oncogenic signaling pathways pivotal to TNBC initiation and progression. Deregulated activation of signal transducer and activator of transcription 3 (STAT3) is fundamental to driving TNBC malignant transformation, highlighting STAT3 as a promising TNBC therapeutic target. Methoxyhispolon Methyl Ether (MHME) is an analog of Hispolon, an anti-cancer polyphenol found in the medicinal mushroom Phellinus linteus. Still, MHME's anti-cancer effects and mechanisms remain unknown. Herein, we present the first report about MHME's anti-TNBC effect and its action mechanism. We first revealed that MHME is proapoptotic and cytotoxic against human TNBC cell lines HS578T, MDA-MB-231, and MDA-MB-463 and displayed a more potent cytotoxicity than Hispolon's. Mechanistically, MHME suppressed both constitutive and interleukin 6 (IL-6)-induced activation of STAT3 represented by the extent of tyrosine 705-phosphorylated STAT3 (p-STAT3). Notably, MHME-evoked apoptosis and clonogenicity impairment were abrogated in TNBC cells overexpressing a dominant-active mutant of STAT3 (STAT3-C); supporting the blockade of STAT3 activation is an integral mechanism of MHME's cytotoxic action on TNBC cells. Moreover, MHME downregulated BCL-2 in a STAT3-dependent manner, and TNBC cells overexpressing BCL-2 were refractory to MHME-induced apoptosis, indicating that BCL-2 downregulation is responsible for MHME's proapoptotic effect on TNBC cells. Finally, MHME suppressed SRC activation, while v-src overexpression rescued p-STAT3 levels and downregulated apoptosis in MHME-treated TNBC cells. Collectively, we conclude that MHME provokes TNBC cell apoptosis through the blockade of the SRC/STAT3/BCL-2 pro-survival axis. Our findings suggest the potential of applying MHME as a TNBC chemotherapy agent.

A STAT3 protein complex required for mitochondrial mRNA stability and cancer

Signal transducer and activator of transcription 3 (STAT3) is a potent transcription factor necessary for life whose activity is corrupted in diverse diseases, including cancer. STAT3 biology was presumed to be entirely dependent on its activity as a transcription factor until the discovery of a mitochondrial pool of STAT3, which is necessary for normal tissue function and tumorigenesis. However, the mechanism of this mitochondrial activity remained elusive. This study uses immunoprecipitation and mass spectrometry to identify a complex containing STAT3, leucine-rich pentatricopeptide repeat containing (LRPPRC), and SRA stem-loop-interacting RNA-binding protein (SLIRP) that is required for the stability of mature mitochondrially encoded mRNAs and transport to the mitochondrial ribosome. Moreover, we show that this complex is enriched in patients with lung adenocarcinoma and that its deletion inhibits the growth of lung cancer in vivo, providing therapeutic opportunities through the specific targeting of the mitochondrial activity of STAT3.

Mechanism of Bazhen decoction in the treatment of colorectal cancer based on network pharmacology, molecular docking, and experimental validation

Objective

Bazhen Decoction (BZD) is a common adjuvant therapy drug for colorectal cancer (CRC), although its anti-tumor mechanism is unknown. This study aims to explore the core components, key targets, and potential mechanisms of BZD treatment for CRC.

Methods

The Traditional Chinese Medicine Systems Pharmacology (TCMSP) was employed to acquire the BZD's active ingredient and targets. Meanwhile, the Drugbank, Therapeutic Target Database (TTD), DisGeNET, and GeneCards databases were used to retrieve pertinent targets for CRC. The Venn plot was used to obtain intersection targets. Cytoscape software was used to construct an "herb-ingredient-target" network and identify core targets. GO and KEGG pathway enrichment analyses were conducted using R language software. Molecular docking of key ingredients and core targets of drugs was accomplished using PyMol and Autodock Vina software. Cell and animal research confirmed Bazhen Decoction efficacy and mechanism in treating colorectal cancer.

Results

BZD comprises 173 effective active ingredients. Using four databases, 761 targets related to CRC were identified. The intersection of BZD and CRC yielded 98 targets, which were utilized to construct the "herb-ingredient-target" network. The four key effector components with the most targets were quercetin, kaempferol, licochalcone A, and naringenin. Protein-protein interaction (PPI) analysis revealed that the core targets of BZD in treating CRC were AKT1, MYC, CASP3, ESR1, EGFR, HIF-1A, VEGFR, JUN, INS, and STAT3. The findings from molecular docking suggest that the core ingredient exhibits favorable binding potential with the core target. Furthermore, the GO and KEGG enrichment analysis demonstrates that BZD can modulate multiple signaling pathways related to CRC, like the T cell receptor, PI3K-Akt, apoptosis, P53, and VEGF signaling pathway. In vitro, studies have shown that BZD dose-dependently inhibits colon cancer cell growth and invasion and promotes apoptosis. Animal experiments have shown that BZD treatment can reverse abnormal expression of PI3K, AKT, MYC, EGFR, HIF-1A, VEGFR, JUN, STAT3, CASP3, and TP53 genes. BZD also increases the ratio of CD4+ T cells to CD8+ T cells in the spleen and tumor tissues, boosting IFN-γ expression, essential for anti-tumor immunity. Furthermore, BZD has the potential to downregulate the PD-1 expression on T cell surfaces, indicating its ability to effectively restore T cell function by inhibiting immune checkpoints. The results of HE staining suggest that BZD exhibits favorable safety profiles.

Conclusion

BZD treats CRC through multiple components, targets, and metabolic pathways. BZD can reverse the abnormal expression of genes such as PI3K, AKT, MYC, EGFR, HIF-1A, VEGFR, JUN, STAT3, CASP3, and TP53, and suppresses the progression of colorectal cancer by regulating signaling pathways such as PI3K-AKT, P53, and VEGF. Furthermore, BZD can increase the number of T cells and promote T cell activation in tumor-bearing mice, enhancing the immune function against colorectal cancer. Among them, quercetin, kaempferol, licochalcone A, naringenin, and formaronetin are more highly predictive components related to the T cell activation in colorectal cancer mice. This study is of great significance for the development of novel anti-cancer drugs. It highlights the importance of network pharmacology-based approaches in studying complex traditional Chinese medicine formulations.

A pan-cancer analysis of STAT3 expression and genetic alterations in human tumors

Combined cancer immunotherapy and targeted therapy have proven to be effective against various cancers and therefore have recently become the focus of cancer research. Signal transducer and activator of transcription 3 (STAT3) is a member of the STAT protein family of transcription factors. Several studies have shown that STAT3 can affect the prognosis of cancer patients by regulating immune microenvironment (IME). Therefore, STAT3 may have high research value for the development of combined immunotherapy/targeted therapy approaches for the treatment of cancer patients. We found differences in STAT3 expression between tumor and normal tissues. Kaplan-Meier survival and Cox regression analyses showed that high expression of STAT3 is associated with poor prognosis in low-grade glioma (LGG) patients. The results of the analysis of the area under the curve of the receiver operating characteristic curve further suggested that the expression of STAT3 is an effective way to evaluate the prognosis of patients with glioma. The results of the IME analysis revealed that the immune and matrix scores of LGGs were positively correlated with the expression of STAT3 (P < 0.05). The results of immune cell infiltration analysis showed that STAT3 was positively correlated with resting dendritic cells, eosinophils, neutrophils, M0 macrophages, M1 macrophages, CD4 memory resting T cells, and CD8 T cells in LGG patients, but negatively correlated with activated mast cells and M2 macrophages (P < 0.05). Our gene set enrichment analysis identified 384 enriched pathways. According to the enrichment scores, the top ten most significantly upregulated pathways were related to immune response. The top ten most significantly downregulated pathways were related to cell signal transduction and the regulation of cell survival, proliferation, and metabolism. Genetic alteration analysis showed that missense mutations in STAT3 account for the majority of mutations, and STAT3 mutations mostly occur in the Src homology domain. In conclusion overexpression of STAT3 can promote the development and growth of tumors by regulating IME, which is significantly related to the poor prognosis of cancer patients. Therefore, targeted inhibition of STAT3 expression may have high research value for the development of combined immunotherapy/targeted therapy approaches for the treatment of cancer patients.

Blockade of the SRC/STAT3/BCL-2 Signaling Axis Sustains the Cytotoxicity in Human Colorectal Cancer Cell Lines Induced by Dehydroxyhispolon Methyl Ether

Colorectal cancer (CRC) is the third most prevalent human cancer globally. 5-Fluorouracil (5-FU)-based systemic chemotherapy is the primary strategy for advanced CRC treatment, yet is limited by poor response rate. Deregulated activation of signal transducer and activator of transcription 3 (STAT3) is fundamental to driving CRC malignant transformation and a poor prognostic marker for CRC, underscoring STAT3 as a promising CRC drug target. Dehydroxyhispolon methyl ether (DHME) is an analog of Hispolon, an anticancer polyphenol abundant in the medicinal mushroom Phellinus linteus. Previously, we have established DHME's cytotoxic effect on human CRC cell lines by eliciting apoptosis through the blockade of WNT/β-catenin signaling, a preeminent CRC oncogenic pathway. Herein, we unraveled that compared with 5-FU, DHME is a more potent killer of CRC cells while being much less toxic to normal colon epithelial cells. DHME suppressed both constitutive and interleukin 6 (IL-6)-induced STAT3 activation represented by tyrosine 705 phosphorylation of STAT3 (p-STAT3 (Y705)); notably, DHME-induced CRC apoptosis and clonogenicity limitation were abrogated by ectopic expression of STAT3-C, a dominant-active STAT3 mutant. Additionally, we proved that BCL-2 downregulation caused by DHME-mediated STAT3 blockage is responsible for DHME-induced CRC cell apoptosis. Lastly, DHME inhibited SRC activation, and v-src overexpression restored p-STAT3 (Y705) levels along with lowering the levels of apoptosis in DHME-treated CRC cells. We conclude DHME provokes CRC cell apoptosis by blocking the SRC/STAT3/BCL-2 axis besides thwarting WNT/β-catenin signaling. The notion that DHME targets two fundamental CRC signaling pathways underpins the potential of DHME as a CRC chemotherapy agent.

STAT3 is a genetic modifier of TGF-beta induced EMT in KRAS mutant pancreatic cancer

Oncogenic mutations in KRAS are among the most common in cancer. Classical models suggest that loss of epithelial characteristics and the acquisition of mesenchymal traits are associated with cancer aggressiveness and therapy resistance. However, the mechanistic link between these phenotypes and mutant KRAS biology remains to be established. Here we identify STAT3 as a genetic modifier of TGF-beta-induced epithelial to mesenchymal transition. Gene expression profiling of pancreatic cancer cells identifies more than 200 genes commonly regulated by STAT3 and oncogenic KRAS. Functional classification of STAT3 responsive program reveals its major role in tumor maintenance and epithelial homeostasis. The signatures of STAT3-activated cell states can be projected onto human KRAS mutant tumors, suggesting that they faithfully reflect characteristics of human disease. These observations have implications for therapeutic intervention and tumor aggressiveness.

Neural stem cell-derived extracellular vesicles: The light of central nervous system diseases

Central nervous system (CNS) diseases are the leading cause of death worldwide. By performing compensatory functions and improving the inflammatory microenvironment, the transplantation of neural stem cells (NSCs) can promote functional recovery from brain injury, aging, brain tumours, and other diseases. However, the ability of NSCs to differentiate into neurons is limited, and they are associated with a risk of tumourigenicity. NSC-derived extracellular vesicles (NSC-EVs) can modulate the local microenvironment of the nervous system as well as distant neuronal functions. Thus, cell-free therapy may be a novel remedy for CNS disorders. This article reviews the characteristics, contents, and mechanisms of action of NSC-EVs as well as their roles and application prospects in various CNS diseases.

Acetyl-cinobufagin suppresses triple-negative breast cancer progression by inhibiting the STAT3 pathway

BACKGROUND

The incidence of breast cancer (BC) worldwide has increased substantially in recent years. Epithelial-mesenchymal transition (EMT) refers to a crucial event impacting tumor heterogeneity. Although cinobufagin acts as an effective anticancer agent, the clinical use of cinobufagin is limited due to its strong toxicity. Acetyl-cinobufagin, a pre-drug of cinobufagin, was developed and prepared with greater efficacy and lower toxicity.

METHODS

A heterograft mouse model using triple negative breast cancer (TNBC) cell lines, was used to evaluate the potency of acetyl-cinobufagin. Signal transducer and stimulator of transcription 3 (STAT3)/EMT involvement was investigated by gene knockout experiments using siRNA and Western blot analysis.

RESULTS

Acetyl-cinobufagin inhibited proliferation, migration, and cell cycle S/G2 transition and promoted apoptosis in TNBC cells in vitro. In general, IL6 triggered the phosphorylation of the transcription factor STAT3 thereby activating the STAT3 pathway and inducing EMT. Mechanistically, acetyl-cinobufagin suppressed the phosphorylation of the transcription factor STAT3 and blocked the interleukin (IL6)-triggered translocation of STAT3 to the cell nucleus. In addition, acetyl-cinobufagin suppressed EMT in TNBC by inhibiting the STAT3 pathway. Experiments in an animal model of breast cancer clearly showed that acetyl-cinobufagin was able to reduce tumor growth.

CONCLUSIONS

The findings of this study support the potential clinical use of acetyl-cinobufagin as a STAT3 inhibitor in TNBC adjuvant therapy.

Precise and efficient C-to-U RNA base editing with SNAP-CDAR-S

Site-directed RNA base editing enables the transient and dosable change of genetic information and represents a recent strategy to manipulate cellular processes, paving ways to novel therapeutic modalities. While tools to introduce adenosine-to-inosine changes have been explored quite intensively, the engineering of precise and programmable tools for cytidine-to-uridine editing is somewhat lacking behind. Here we demonstrate that the cytidine deaminase domain evolved from the ADAR2 adenosine deaminase, taken from the RESCUE-S tool, provides very efficient and highly programmable editing when changing the RNA targeting mechanism from Cas13-based to SNAP-tag-based. Optimization of the guide RNA chemistry further allowed to dramatically improve editing yields in the difficult-to-edit 5'-CCN sequence context thus improving the substrate scope of the tool. Regarding editing efficiency, SNAP-CDAR-S outcompeted the RESCUE-S tool clearly on all tested targets, and was highly superior in perturbing the β-catenin pathway. NGS analysis showed similar, moderate global off-target A-to-I and C-to-U editing for both tools.

Platinum(IV) Complexes as Inhibitors of STAT3 and Regulators of the Tumor Microenvironment To Control Breast Cancer

Interplay between breast cancer (BC) cells and the tumor microenvironment (TME) influences the outcome of cancer treatment. Aberrant activation of signal transducer and activator of transcription 3 (STAT3) promotes the interaction and causes immunosuppression and drug resistance. Platinum(IV) complexes SPP and DPP bearing pterostilbene-derived axial ligand(s) were synthesized to inhibit the JAK2-STAT3 pathway in BC cells and regulate the TME. These complexes exerted remarkable antiproliferative activity against the triple-negative BC cells, suppressed the expression of phosphorylated STAT3 and STAT3-related cyclooxygenase-2 and IL-6, and activated caspase-3 and cleaved poly ADP-ribose polymerase, preventing the repair of DNA lesions and inducing apoptosis. Furthermore, DPP promoted the maturation and antigen presentation of dendritic cells, repressed the proliferation and differentiation of myeloid-derived suppressor cells and regulatory T cells, and facilitated the expansion of T cells. As a consequence, DPP showed excellent anticancer activity against BC with almost no general toxicity in vivo as a potential chemoimmunotherapeutic agent.

RUNX1-Regulated Signaling Pathways in Ovarian Cancer

Ovarian cancer is the leading cause of gynecological death worldwide, and its poor prognosis and high mortality seriously affect the life of ovarian cancer patients. Runt-related transcription factor 1 (RUNX1) has been widely studied in hematological diseases and plays an important role in the occurrence and development of hematological diseases. In recent years, studies have reported the roles of RUNX1 in solid tumors, including the significantly increased expression of RUNX1 in ovarian cancer. In ovarian cancer, the dysregulation of the RUNX1 signaling pathway has been implicated in tumor progression, metastasis, and response to therapy. At the same time, the decreased expression of RUNX1 in ovarian cancer can significantly improve the sensitivity of clinical chemotherapy and provide theoretical support for the subsequent diagnosis and treatment target of ovarian cancer, providing prognosis and treatment options to patients with ovarian cancer. However, the role of RUNX1 in ovarian cancer remains unclear. Therefore, this article reviews the relationship between RUNX1 and the occurrence and development of ovarian cancer, as well as the closely regulated signaling pathways, to provide some inspiration and theoretical support for future research on RUNX1 in ovarian cancer and other diseases.

Reduced DEFA5 Expression and STAT3 Activation Underlie the Submucosal Invasion of Early Gastric Cancers

INTRODUCTION

Submucosal invasion is a core hallmark of early gastric cancer (EGC) with poor prognosis. However, the molecular mechanism of the progression from intramucosal gastric cancer (IMGC) to early submucosal-invasive gastric cancer (SMGC) is not fully understood. The objective of this study was to identify genes and pathways involved in the submucosal invasion in EGC using comprehensive gene expression analysis.

METHODS

Gene expression profiling was performed for eight cases of IMGC and eight cases of early SMGC with submucosal invasion ≥500 μm. To validate the findings of gene expression analysis and to examine the gene expression pattern in tissues, immunohistochemical (IHC) staining was performed for 50 cases of IMGC and SMGC each.

RESULTS

Gene expression analysis demonstrated that the expression levels of small intestine-specific genes were significantly decreased in SMGC. Among them, defensin alpha 5 (DEFA5) was the most downregulated gene in SMGC, which was further validated in SMGC tissues by IHC staining. Gene set enrichment analysis showed a strong association between SMGC, the JAK-STAT signaling pathway, and the upregulation of STAT3-activating cytokines. The expression of phosphorylated STAT3 was significant in the nucleus of tumor cells in SMGC tissues but not in areas expressing DEFA5.

CONCLUSION

The results of this study strongly suggest that the downregulation of DEFA5 and the activation of STAT3 play a significant role in the submucosal invasion of EGC.

PKCι induces differential phosphorylation of STAT3 to modify STAT3-related signaling pathways in pancreatic cancer cells

An increasing number of studies have documented atypical protein kinase C isoform ι (PKCι) as an oncoprotein playing multifaceted roles in pancreatic carcinogenesis, including sustaining the transformed growth, prohibiting apoptosis, strengthening invasiveness, facilitating autophagy, as well as promoting the immunosuppressive tumor microenvironment of pancreatic tumors. In this study, we present novel evidence that PKCι overexpression increases STAT3 phosphorylation at the Y705 residue while decreasing STAT3 phosphorylation at the S727 residue in pancreatic cancer cells. We further demonstrate that STAT3 phosphorylation at Y705 and S727 residues is mutually antagonistic, and that STAT3 Y705 phosphorylation is positively related to the transcriptional activity of STAT3 in pancreatic cancer cells. Furthermore, we discover that PKCι inhibition attenuates STAT3 transcriptional activity via Y705 dephosphorylation, which appears to be resulted from enhanced phosphorylation of S727 in pancreatic cancer cells. Finally, we investigate and prove that by modulating the STAT3 activity, the PKCι inhibitor can synergistically enhance the antitumor effects of pharmacological STAT3 inhibitors or reverse the anti-apoptotic side effects incited by the MEK inhibitor, thereby posing as a prospective sensitizer in the treatment of pancreatic cancer cells.

Mechanisms of alkaliptosis

Malignant tumors represent a major threat to global health and the search for effective treatments is imperative. While various treatments exist, including surgery, radiotherapy, chemotherapy, immunotherapy and combination therapies, there remains a need to develop therapies that target regulated cell death pathways to eliminate cancer cells while preserving normal cells. Alkaliptosis, a pH-dependent cell death process triggered by the small molecular compound JTC801, has been identified as a novel approach for malignant tumor treatment, particularly in pancreatic cancer. Two major signaling pathways, the NF-κB-CA9 pathway and the ATP6V0D1-STAT3 pathway, contribute to the induction of alkaliptosis. This review summarizes recent developments in our understanding of alkaliptosis signals, mechanisms, and modulation, and explores its context-dependent effects on drug resistance, inflammation, and immunity. By providing a deeper understanding of the heterogeneity and plasticity of cell death mechanisms, this information holds promise for informing the design of more effective anti-tumor therapies.