Tumor-neutrophil cross talk orchestrates the tumor microenvironment to determine the bladder cancer progression.

The immune landscape of bladder cancer progression is not fully understood, and effective therapies are lacking in advanced bladder cancer. Here, we visualized that bladder cancer cells recruited neutrophils by secreting interleukin-8 (IL-8); in turn, neutrophils played dual functions in bladder cancer, including hepatocyte growth factor (HGF) release and CCL3highPD-L1high super-immunosuppressive subset formation. Mechanistically, c-Fos was identified as the mediator of HGF up-regulating IL-8 transcription in bladder cancer cells, which was central to the positive feedback of neutrophil recruitment. Clinically, compared with serum IL-8, urine IL-8 was a better biomarker for bladder cancer prognosis and clinical benefit of immune checkpoint blockade (ICB). Additionally, targeting neutrophils or hepatocyte growth factor receptor (MET) signaling combined with ICB inhibited bladder cancer progression and boosted the antitumor effect of CD8+ T cells in mice. These findings reveal the mechanism by which tumor-neutrophil cross talk orchestrates the bladder cancer microenvironment and provide combination strategies, which may have broad impacts on patients suffering from malignancies enriched with neutrophils.

Promotion of hair growth by a conditioned medium from human umbilical cord mesenchymal stem cells cultivated in a 3D scaffold of gelatin sponge.

BACKGROUND: This study aims to investigate the effects of a conditioned medium (CM) from human umbilical cord mesenchymal stem cells (HuMSCs) cultivated in gelatin sponge (GS-HuMSCs-CM) on hair growth in a mouse model. METHODS: CM was collected from the HuMSCs cultivated in a monolayer or in a gelatin sponge. Vascular endothelial growth factor (VEGF), insulin-like growth factor-1 (IGF-1), keratinocyte growth factor (KGF), and hepatocyte growth factor (HGF) levels in CMs were measured by enzyme-linked immunosorbent assays (ELISAs). A hair loss model by a C57 BL/6J mouse was prepared. The effects of GS-HuMSCs-CM and HuMSCs on hair regrowth in mice were investigated by intradermal injection in the depilated back skin with normal saline (NS) as the control. The time for hair regrowth and full covering in depilated areas was observed, and the hair growth was evaluated histologically and by grossly measuring hair length and diameter. RESULTS: Compared with monolayer cultured cells, the three-dimensional (3D) culture of HuMSCs in gelatin sponge drastically increased VEGF, IGF-1, KGF, and HGF production. GS-HuMSCs-CM and HuMSCs injection both promoted hair regeneration in mice, while GS-HuMSCs-CM presented more enhanced effects in hair length, hair diameter, and growth rate. GS-HuMSCs-CM significantly promoted angiogenesis in injected skin areas, which might also contribute to faster hair regrowth. CONCLUSION: GS-HuMSCs-CM exerted significant effects on inducing hair growth and promoted skin angiogenesis in C57BL/6J mice.

Deficiency of the HGF/Met pathway leads to thyroid dysgenesis by impeding late thyroid expansion.

The mechanisms of bifurcation, a key step in thyroid development, are largely unknown. Here we find three zebrafish lines from a forward genetic screening with similar thyroid dysgenesis phenotypes and identify a stop-gain mutation in hgfa and two missense mutations in met by positional cloning from these zebrafish lines. The elongation of the thyroid primordium along the pharyngeal midline was dramatically disrupted in these zebrafish lines carrying a mutation in hgfa or met. Further studies show that MAPK inhibitor U0126 could mimic thyroid dysgenesis in zebrafish, and the phenotypes are rescued by overexpression of constitutively active MEK or Snail, downstream molecules of the HGF/Met pathway, in thyrocytes. Moreover, HGF promotes thyrocyte migration, which is probably mediated by downregulation of E-cadherin expression. The delayed bifurcation of the thyroid primordium is also observed in thyroid-specific Met knockout mice. Together, our findings reveal that HGF/Met is indispensable for the bifurcation of the thyroid primordium during thyroid development mediated by downregulation of E-cadherin in thyrocytes via MAPK-snail pathway.

Mimicking the cellular environment does not cause monocyte-derived macrophages to become phenotypically similar to Kupffer cells.

Resident macrophages of various mammalian organs are characterized by several distinctive features in their gene expression profile and phenotype, including involvement in the regulation of organ functions, as well as reduced sensitivity to proinflammatory activation factors. The reasons for the formation of such a specific phenotype remain the subject of intensive research. Some papers emphasize the role of the origin of organ macrophages. Other studies indicate that monocytes that develop in the red bone marrow are also able to form resident macrophages with a phenotype characteristic of a particular organ, but this requires appropriate microenvironmental conditions. In this article, we studied the possibility of differentiation of monocyte-derived macrophages into cells with a Kupffer-like phenotype under the influence of the main stromal components of Kupffer cells macrophage niche: Ito cells, liver sinusoid endotheliocytes and hepatocyte growth factor (HGF). It was found that Kupffer cells are characterized by several features, including increased expression of transcription factors Spic and Id3, as well as MUP family genes, Clusterin and Ngp genes. In addition, Kupffer cells were characterized by a higher proliferative activity. The expression of marker genes of Kupffer cells (i.e. Id3, Spic, Marco and Timd4) increased in monocyte-derived macrophages during coculture with Ito cells, liver sinusoid endothelial cells, macrophage colony-stimulating factor and HGF cells only by 3 days. However, the expression level of these genes was always higher in Kupffer cells. In addition, a complete coincidence of the expressed gene profile in monocyte-derived macrophages and Kupffer cells did not occur even after 3 days of culturing.

Exploring the association of POSTN+ cancer-associated fibroblasts with triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is a subtype of breast cancer with a poor prognosis. Cancer-associated fibroblasts (CAFs) play a critical role in regulating TNBC tumor development. This study aimed to identify and characterize a specific subtype of CAFs associated with TNBC. Initially, using high-throughput bulk transcriptomic data in two cohorts, we identified three CAF-related subtypes (CS1, CS2, CS3) in TNBC samples. These three CAFs subtypes were closely linked to the tumor microenvironment. The CS1 subtype exhibited a relatively immune-rich microenvironment and a favourable prognosis, whereas the CS3 subtype displayed an immune-deprived tumor microenvironment and an unfavourable prognosis. Through WGCNA analysis, POSTN was identified as a key biomarker for CAFs associated with TNBC. Then, POSTN+CAFs was identified and characterized. Both POSTN and POSTN+CAFs showed significant positive correlations with stromal molecules HGF and MET at both the transcriptional and protein levels. Specifically co-localized with CAFs in the tumor stromal area, POSTN, produced by POSTN+CAFs, could modulate the HGF-MET axis, serving as a bypass activation pathway to regulate tumor cell proliferation in response to EGFR inhibitor and MET inhibitor. This study underscores the significance of POSTN and POSTN+CAFs as crucial targets for the diagnosis and treatment of TNBC.

Inhibiting Hippo pathway kinases releases WWC1 to promote AMPAR-dependent synaptic plasticity and long-term memory in mice.

The localization, number, and function of postsynaptic AMPA-type glutamate receptors (AMPARs) are crucial for synaptic plasticity, a cellular correlate for learning and memory. The Hippo pathway member WWC1 is an important component of AMPAR-containing protein complexes. However, the availability of WWC1 is constrained by its interaction with the Hippo pathway kinases LATS1 and LATS2 (LATS1/2). Here, we explored the biochemical regulation of this interaction and found that it is pharmacologically targetable in vivo. In primary hippocampal neurons, phosphorylation of LATS1/2 by the upstream kinases MST1 and MST2 (MST1/2) enhanced the interaction between WWC1 and LATS1/2, which sequestered WWC1. Pharmacologically inhibiting MST1/2 in male mice and in human brain-derived organoids promoted the dissociation of WWC1 from LATS1/2, leading to an increase in WWC1 in AMPAR-containing complexes. MST1/2 inhibition enhanced synaptic transmission in mouse hippocampal brain slices and improved cognition in healthy male mice and in male mouse models of Alzheimer's disease and aging. Thus, compounds that disrupt the interaction between WWC1 and LATS1/2 might be explored for development as cognitive enhancers.

Cold-shock Domain Protein A (CSDA) Influences Hepatocyte Growth Factor-medicated Cell Proliferation and Metastasis in Gastric Cancer Cells.

BACKGROUND/AIM: A role for cold-shock domain (CSD) proteins in abnormal cell proliferation has been suggested in the literature. The aim of this study was to investigate the effect of hepatocyte growth factor (HGF)-induced up-regulation of CSD protein A (CSDA) expression on vascular endothelial growth factor (VEGF) expression and its role in gastric cancer cell invasion and proliferation. MATERIALS AND METHODS: We assessed effects on two gastric cancer cell lines using reverse transcription-polymerase chain reaction, western blotting, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays, and CSDA knockdown with short hairpin RNA. RESULTS: Hepatocyte growth factor (HGF) elevates CSDA levels in gastric cancer cell lines. To elucidate the mechanism by which HGF prompts CSDA expression and its impact on vascular endothelial growth factor (VEGF), we applied the Mitogen Activated Protein Kinase (MAPK) inhibitor PD098059 and conducted analyses using western blot. Following the administration of PD098059, a reduction in the protein levels of HGF-stimulated VEGF was observed. Additionally, silencing of CSDA resulted in diminished levels of both VEGF and phosphorylated extracellular signal-regulated kinase (ERK). The suppression of CSDA also led to reduced HGF-induced cell proliferation and diminished invasive capabilities in vitro. Furthermore, our research pinpointed a potential activator protein-1 (AP-1) binding site within the VEGF promoter zone, validating its activity via chromatin immunoprecipitation assays. Electrophoretic mobility shift assays further disclosed that HGF-induced CSDA augmentation correlates with an increase in AP-1 binding to VEGF. CONCLUSION: CSDA is crucial for the proliferation of gastric cancer cells, and the inhibition of this protein could impede the advancement of gastric cancer.

Endocytic activation and exosomal secretion of matriptase stimulate the second wave of EGF signaling to promote skin and breast cancer invasion.

The dysfunction of matriptase, a membrane-anchored protease, is highly related to the progression of skin and breast cancers. Epidermal growth factor (EGF)-induced matriptase activation and cancer invasion are known but with obscure mechanisms. Here, we demonstrate a vesicular-trafficking-mediated interplay between matriptase and EGF signaling in cancer promotion. We found that EGF induces matriptase to undergo endocytosis together with the EGF receptor, followed by acid-induced activation in endosomes. Activated matriptase is then secreted extracellularly on exosomes to catalyze hepatocyte growth factor precursor (pro-HGF) cleavage, resulting in autocrine HGF/c-Met signaling. Matriptase-induced HGF/c-Met signaling represents the second signal wave of EGF, which promotes cancer cell scattering, migration, and invasion. These findings demonstrate a role of vesicular trafficking in efficient activation and secretion of membrane matriptase and a reciprocal regulation of matriptase and EGF signaling in cancer promotion, providing insights into the physiological functions of vesicular trafficking and the molecular pathological mechanisms of skin and breast cancers.

Unlocking c-MET: A comprehensive journey into targeted therapies for breast cancer.

Breast cancer is the most common malignancy among women, posing a formidable health challenge worldwide. In this complex landscape, the c-MET (cellular-mesenchymal epithelial transition factor) receptor tyrosine kinase (RTK), also recognized as the hepatocyte growth factor (HGF) receptor (HGFR), emerges as a prominent protagonist, displaying overexpression in nearly 50% of breast cancer cases. Activation of c-MET by its ligand, HGF, secreted by neighboring mesenchymal cells, contributes to a cascade of tumorigenic processes, including cell proliferation, metastasis, angiogenesis, and immunosuppression. While c-MET inhibitors such as crizotinib, capmatinib, tepotinib and cabozantinib have garnered FDA approval for non-small cell lung cancer (NSCLC), their potential within breast cancer therapy is still undetermined. This comprehensive review embarks on a journey through structural biology, multifaceted functions, and intricate signaling pathways orchestrated by c-MET across cancer types. Furthermore, we highlight the pivotal role of c-MET-targeted therapies in breast cancer, offering a clinical perspective on this promising avenue of intervention. In this pursuit, we strive to unravel the potential of c-MET as a beacon of hope in the fight against breast cancer, unveiling new horizons for therapeutic innovation.

TWIST1 is a critical downstream target of the HGF/MET pathway and is required for MET driven acquired resistance in oncogene driven lung cancer.

MET amplification/mutations are important targetable oncogenic drivers in NSCLC, however, acquired resistance is inevitable and the majority of patients with targetable MET alterations fail to respond to MET tyrosine kinase inhibitors (TKIs). Furthermore, MET amplification is among the most common mediators of TKI resistance. As such, novel therapies to target MET pathway and overcome MET TKI resistance are clearly needed. Here we show that the epithelial-mesenchymal transition (EMT) transcription factor, TWIST1 is a key downstream mediator of HGF/MET induced resistance through suppression of p27 and targeting TWIST1 can overcome resistance. We found that TWIST1 is overexpressed at the time of TKI resistance in multiple MET-dependent TKI acquired resistance PDX models. We have shown for the first time that MET directly stabilized the TWIST protein leading to TKI resistance and that TWIST1 was required for MET-driven lung tumorigenesis as well as could induce MET TKI resistance when overexpressed. TWIST1 mediated MET TKI resistance through suppression of p27 expression and genetic or pharmacologic inhibition of TWIST1 overcame TKI resistance in vitro and in vivo. Our findings suggest that targeting TWIST1 may be an effective therapeutic strategy to overcome resistance in MET-driven NSCLC as well as in other oncogene driven subtypes in which MET amplification is the resistance mechanism.

Hypoxia preconditioning of human amniotic mesenchymal stem cells enhances proliferation and migration and promotes their homing via the HGF/C-MET signaling axis to augment the repair of acute liver failure.

BACKGROUND: Transplantation of mesenchymal stem cells (MSCs) is a newly developed strategy for treating acute liver failure (ALF). Nonetheless, the low survival rate of MSCs after transplantation and their poor homing to damaged tissues limit the clinical application of MSCs. The research assessed whether hypoxic preconditioning (HPC) can improve the biological activity of human amniotic mesenchymal stem cells (hA-MSCs), promote their homing ability to the liver of mice with ALF, and influence liver tissue repair. METHODS: Flow cytometry, CCK8, Transwell, and Western blotting assays were conducted to assess the effects of hypoxic preconditioning on the phenotype, proliferation, and migration of hA-MSCs and the changes in the c-Met and CXCR4 gene expression levels were studied. To evaluate the effects of the transplantation of hypoxic preconditioning of hA-MSCs on the homing and repair of D-galactosamine (D-GalN)/LPS-induced ALF, the mechanism was elucidated by adding c-Met, CXCR4-specific blockers (SU11274 and AMD3100). RESULTS: After hypoxia pretreatment (1% oxygen volume fraction), hA-MSCs maintained the morphological characteristics of adherence and vortex colony growth and showed high CD44, CD90, and CD105 and low CD31, CD34, and CD45 expression levels. Hypoxic preconditioning of hA-MSCs significantly increased their proliferation and migration and highly expressed the c-Met and CXCR4 genes. In vivo and in vitro, this migration-promoting effect was suppressed by the c-Met specific blocker SU11274. In the acute liver failure mouse model, the HGF expression level was considerably elevated in the liver than that in the serum, lungs and kidneys. The transplantation of hypoxic preconditioned hA-MSCs introduced a remarkable improvement in the liver function and survival rate of mice with ALF and enhanced the anti-apoptosis ability of liver cells. The anti-apoptotic enhancing effect of hypoxic preconditioning was suppressed by the c-Met specific blocker SU11274. Hypoxic hA-MSCs administration was observed to have considerably increased the fluorescent cells in the liver than that recorded after administering normal oxygen-hA-MSCs. The number of hepatic fluorescent cells decreased remarkably after adding the c-Met inhibitor SU11274, compared to that recorded after hypoxic pretreatment, whereas the effect of c-Met inhibitor SU11274 on normal oxygen-hA-MSCs was not significant. CONCLUSIONS: Hypoxic preconditioning depicted no impact on the morphology and phenotype features of the human amniotic mesenchymal stem cells, but it can promote their proliferation, migration, anti-apoptotic effect, and homing rate and improve the repair of acute liver failure, which might be mediated by the HGF/c-Met signaling axis.

Androgen deprivation induces double-null prostate cancer via aberrant nuclear export and ribosomal biogenesis through HGF and Wnt activation.

Androgen deprivation therapy (ADT) targeting androgen/androgen receptor (AR)- signaling pathways is the main therapy for advanced prostate cancer (PCa). However, ADT eventually fails in most patients who consequently develop castration-resistant prostate cancer (CRPC). While more potent AR antagonists and blockers for androgen synthesis were developed to improve clinical outcomes, they also show to induce more diverse CRPC phenotypes. Specifically, the AR- and neuroendocrine-null PCa, DNPC, occurs in abiraterone and enzalutamide-treated patients. Here, we uncover that current ADT induces aberrant HGF/MET signaling activation that further elevates Wnt/ß-catenin signaling in human DNPC samples. Co-activation of HGF/MET and Wnt/ß-catenin axes in mouse prostates induces DNPC-like lesions. Single-cell RNA sequencing analyses identify increased expression and activity of XPO1 and ribosomal proteins in mouse DNPC-like cells. Elevated expression of XPO1 and ribosomal proteins is also identified in clinical DNPC specimens. Inhibition of XPO1 and ribosomal pathways represses DNPC growth in both in vivo and ex vivo conditions, evidencing future therapeutic targets.

Hepatocyte growth factor as indicator for subclinical atherosclerosis.

Background: Hepatocyte growth factor (HGF) is a pleiotropic cytokine mainly produced by mesenchymal cells. After endothelial damage by oxidized low-density lipoprotein (LDL), HGF is produced and released into the circulation in response. Due to this mechanism HGF has been proposed as possible clinical biomarker for clinical as well as subclinical atherosclerosis. Patients and methods: The conducted study is an observational, single centre, cohort study, including 171 patients with at least one cardiovascular risk factor or already established cardiovascular disease (CVD). Each patient underwent 3D plaque volumetry of the carotid and femoral arteries as well as physical examination and record of the medical history. Additionally, plasma HGF and further laboratory parameters like high sensitivity C-reactive protein and LDL-cholesterol were determined. Results: 169 patients were available for statistical analysis. In bivariate correlation, HGF showed a highly significant correlation with total plaque volume (TPV, r=0.48; p<0.001). In receiver operating characteristic (ROC) analysis for high TPV, HGF showed an area under the curve (AUC) of 0.68 (CI 95%: 0.59-0.77, p<0.001) with a sensitivity of 78% and a specificity of 52% to predict high TPV at a cut-off of 959 ng/ml. In the ROC-analysis for the presence of CVD, HGF demonstrated an AUC of 0.65 (95% CI 0.55-0.73; p=0.01) with a sensitivity of 77% and a specificity of 52%. Conclusions: Higher plasma levels of HGF are associated with higher atherosclerotic plaque volume as measured by 3D-ultrasound.

Inhibition of autocrine HGF maturation overcomes cetuximab resistance in colorectal cancer.

Although amplifications and mutations in receptor tyrosine kinases (RTKs) act as bona fide oncogenes, in most cancers, RTKs maintain moderate expression and remain wild-type. Consequently, cognate ligands control many facets of tumorigenesis, including resistance to anti-RTK therapies. Herein, we show that the ligands for the RTKs MET and RON, HGF and HGFL, respectively, are synthesized as inactive precursors that are activated by cellular proteases. Our newly generated HGF/HGFL protease inhibitors could overcome both de novo and acquired cetuximab resistance in colorectal cancer (CRC). Conversely, HGF overexpression was necessary and sufficient to induce cetuximab resistance and loss of polarity. Moreover, HGF-induced cetuximab resistance could be overcome by the downstream MET inhibitor, crizotinib, and upstream protease inhibitors. Additionally, HAI-1, an endogenous inhibitor of HGF proteases, (i) was downregulated in CRC, (ii) exhibited increased genomic methylation that correlated with poor prognosis, (iii) HAI-1 expression correlated with cetuximab response in a panel of cancer cell lines, and (iv) exogenous addition of recombinant HAI-1 overcame cetuximab resistance in CC-HGF cells. Thus, we describe a targetable, autocrine HAI-1/Protease/HGF/MET axis in cetuximab resistance in CRC.

Basal MET phosphorylation is an indicator of hepatocyte dysregulation in liver disease.

Chronic liver diseases are worldwide on the rise. Due to the rapidly increasing incidence, in particular in Western countries, metabolic dysfunction-associated steatotic liver disease (MASLD) is gaining importance as the disease can develop into hepatocellular carcinoma. Lipid accumulation in hepatocytes has been identified as the characteristic structural change in MASLD development, but molecular mechanisms responsible for disease progression remained unresolved. Here, we uncover in primary hepatocytes from a preclinical model fed with a Western diet (WD) an increased basal MET phosphorylation and a strong downregulation of the PI3K-AKT pathway. Dynamic pathway modeling of hepatocyte growth factor (HGF) signal transduction combined with global proteomics identifies that an elevated basal MET phosphorylation rate is the main driver of altered signaling leading to increased proliferation of WD-hepatocytes. Model-adaptation to patient-derived hepatocytes reveal patient-specific variability in basal MET phosphorylation, which correlates with patient outcome after liver surgery. Thus, dysregulated basal MET phosphorylation could be an indicator for the health status of the liver and thereby inform on the risk of a patient to suffer from liver failure after surgery.

Thrombin Priming Promotes the Neuroprotective Effects of Human Wharton's Jelly-Derived Mesenchymal Stem Cells Via the HGF/AKT/STAT3 Signaling Pathway.

Mesenchymal stem cells (MSCs) directly differentiate into neurons and endothelial cells after transplantation, and their secretome has considerable potential for treating brain injuries. Previous studies have suggested that the effects of MSCs priming with exposure to hypoxia, cytokines, growth factors, or chemical agents could optimize the paracrine potency and therapeutic potential of MSCs. Studies have suggested that thrombin-primed Wharton's Jelly-derived mesenchymal stem cells (Th.WJ-MSCs) significantly enhance the neuroprotective beneficial effects of naive MSCs in brain injury such as hypoxic-ischemic brain injury (HIE) and intraventricular hemorrhage (IVH). This study aimed to characterize WJ-MSCs in terms of stem cell markers, differentiation, cell proliferation, and paracrine factors by comparing naive and Th.WJ-MSCs. We demonstrated that compared with naive MSCs, Th.MSCs significantly enhanced the neuroprotective effects in vitro. Moreover, we identified differentially expressed proteins in the conditioned media of naive and Th.WJ-MSCs by liquid chromatography-tandem mass spectrometry analysis. Secretome analysis of the conditioned medium of WJ-MSCs revealed that such neuroprotective effects were mediated by paracrine effects with secretomes of Th.WJ-MSCs, and hepatocyte growth factor was identified as a key paracrine mediator. These results can be applied further in the preclinical and clinical development of effective and safe cell therapeutics for brain injuries such as HIE and IVH.

HGF facilitates methylation of MEG3, potentially implicated in vemurafenib resistance in melanoma.

BACKGROUND: Melanoma, a frequently encountered cutaneous malignancy characterized by a poor prognosis, persists in presenting formidable challenges despite the advancement in molecularly targeted drugs designed to improve survival rates significantly. Unfortunately, as more therapeutic choices have developed over time, the gradual emergence of drug resistance has become a notable impediment to the effectiveness of these therapeutic interventions. The hepatocyte growth factor (HGF)/c-met signaling pathway has attracted considerable attention, associated with drug resistance stemming from multiple potential mutations within the c-met gene. The activation of the HGF/c-met pathway operates in an autocrine manner in melanoma. Notably, a key player in the regulatory orchestration of HGF/c-met activation is the long non-coding RNA MEG3. METHODS: Melanoma tissues were collected to measure MEG3 expression. In vitro validation was performed on MEG3 to prove its oncogenic roles. Bioinformatic analyses were conducted on the TCGA database to build the MEG3-related score. The immune characteristics and mutation features of the MEG3-related score were explored. RESULTS: We revealed a negative correlation between HGF and MEG3. In melanoma cells, HGF inhibited MEG3 expression by augmenting the methylation of the MEG3 promoter. Significantly, MEG3 exhibits a suppressive impact on the proliferation and migration of melanoma cells, concurrently inhibiting c-met expression. Moreover, a predictive model centered around MEG3 demonstrates notable efficacy in forecasting critical prognostic indicators, immunological profiles, and mutation statuses among melanoma patients. CONCLUSIONS: The present study highlights the potential of MEG3 as a pivotal regulator of c-met, establishing it as a promising candidate for targeted drug development in the ongoing pursuit of effective therapeutic interventions.

Tumor-associated Macrophages Mediate Gefitinib Resistance in Lung Cancer through HGF/c-met Signaling Pathway.

BACKGROUND: The biological behavior of cells changes after they develop drug resistance, and the degree of resistance will be affected by the tumor microenvironment. In this study, we aimed to study the effects of M2 macrophages on gefitinib resistance. METHODS: We polarized THP-1 cells into M0 and M2 macrophages, and conducted various experiments to investigate the effects of M2 macrophages on gefitinib resistance in lung cancer. RESULTS: We found that M2 macrophages promote gefitinib resistance in HCC827 and PC9 cells. In addition, we used ELISA to measure the secretion level of HGF. HGF secretion levels were significantly increased in M2 macrophages. Exogenous HGF remarkably increased the proliferation and invasion in HCC827 and PC9 cells. However, the addition of anti-HGF antibodies abolished the proliferation and invasion of both HCC827 and PC9 cells promoted by M2 macrophages. Furthermore, M2 macrophages or exogenous HGF significantly increased the expression of p-met and p-ERK in HCC827 and PC9 cells, while anti-HGF antibodies diminished the expression of p-met and p-ERK by neutralizing HGF in M2 macrophages. CONCLUSION: Our results revealed that M2 macrophages promote gefitinib resistance by activating ERK and HGF/c-met signaling pathways in HCC827 and PC9 cells. Our findings provide a new therapeutic strategy for gefitinib resistance in lung cancer.

USP11 potentiates HGF/AKT signaling and drives metastasis in hepatocellular carcinoma.

USP11 is a member of the ubiquitin-specific protease family and plays a crucial role in tumor progression in various cancers. However, the precise mechanism by which USP11 promotes EMT and metastasis in hepatocellular carcinoma (HCC) is not fully understood. In this study, we demonstrated that the USP11 expression was dramatically upregulated in HCC tissues and cell lines. Increased USP11 expression was closely associated with tumor number, vascular invasion, and poor prognosis. Functional experiments demonstrated that USP11 markedly promoted metastasis and EMT in HCC via induction of the transcription factor Snail. Mechanistically, USP11 interacted with and deubiquitinated eEF1A1 on Lys439, thereby inhibiting its ubiquitin-mediated degradation. Subsequently, the elevated expression of eEF1A1 resulted in its binding to SP1, which in turn drove the binding of SP1 to its target HGF gene promoter to increase its transcription. This led to an enhanced expression of HGF and the activation of the downstream PI3K/AKT signaling pathway. We demonstrated that USP11 promotes EMT and metastasis in HCC via eEF1A1/SP1/HGF dependent-EMT. Our findings suggest that the USP11/ eEF1A1/SP1/HGF axis contributes to metastasis in HCC, and therefore, could be considered as a potential therapeutic target for the treatment of HCC.

Intercellular Interactions Mediated by HGF And TGF-Β Promote the 3D Spherical and Xenograft Growth of Liver Cancer Cells.

BACKGROUND: Recently, the importance of the interactions between liver cancer cells and fibroblasts has been increasingly recognized; however, many details remain to be explored. METHODS: In this work, we first studied their intercellular interactions using conditioned medium from mouse embryonic fibroblasts (MEFs), then through a previously established coculture model. RESULTS: Culturing in a conditioned medium from MEFs could significantly increase the growth, migration, and invasion of liver cancer cells. The coculture model further demonstrated that a positive feedback loop was formed between transforming growth factor-ß (TGF-ß) from HepG2 cells and mHGF (mouse hepatocyte growth factor) from MEFs during coculture. In this feedback loop, c-Met expression in HepG2 cells was significantly increased, and its downstream signaling pathways, such as Src/FAK, PI3K/AKT, and RAF/MEK/ERK, were activated. Moreover, the proportion of activated MEFs was also increased. More importantly, the growth-promoting effects caused by the interaction of these two cell types were validated in vitro by a 3D spheroid growth assay and in vivo by a xenograft mouse model. CONCLUSION: Collectively, these findings provide valuable insights into the interactions between fibroblasts and liver cancer cells, which may have therapeutic implications for the treatment of liver cancer.