Functional analysis of aortic endothelial cells expressing mutant PDGF receptors with respect to expression of matrix metalloproteinase-3

Metastasis and basement membrane-related signature enhances hepatocellular carcinoma prognosis and diagnosis by integrating single-cell RNA sequencing analysis and immune microenvironment assessment

BACKGROUND

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer and second leading cause of cancer-related deaths worldwide. The heightened mortality associated with HCC is largely attributed to its propensity for metastasis, which cannot be achieved without remodeling or loss of the basement membrane (BM). Despite advancements in targeted therapies and immunotherapies, resistance and limited efficacy in late-stage HCC underscore the urgent need for better therapeutic options and early diagnostic biomarkers. Our study aimed to address these gaps by investigating and evaluating potential biomarkers to improve survival outcomes and treatment efficacy in patients with HCC.

METHOD

In this study, we collected the transcriptome sequencing, clinical, and mutation data of 424 patients with HCC from The Cancer Genome Atlas (TCGA) and 240 from the International Cancer Genome Consortium (ICGC) databases. We then constructed and validated a prognostic model based on metastasis and basement membrane-related genes (MBRGs) using univariate and multivariate Cox regression analyses. Five immune-related algorithms (CIBERSORT, QUANTISEQ, MCP counter, ssGSEA, and TIMER) were then utilized to examine the immune landscape and activity across high- and low-risk groups. We also analyzed Tumor Mutation Burden (TMB) values, Tumor Immune Dysfunction and Exclusion (TIDE) scores, mutation frequency, and immune checkpoint gene expression to evaluate immune treatment sensitivity. We analyzed integrin subunit alpha 3 (ITGA3) expression in HCC by performing single-cell RNA sequencing (scRNA-seq) analysis using the TISCH 2.0 database. Lastly, wound healing and transwell assays were conducted to elucidate the role of ITGA3 in tumor metastasis.

RESULTS

Patients with HCC were categorized into high- and low-risk groups based on the median values, with higher risk scores indicating worse overall survival. Five immune-related algorithms revealed that the abundance of immune cells, particularly T cells, was greater in the high-risk group than in the low-risk group. The high-risk group also exhibited a higher TMB value, mutation frequency, and immune checkpoint gene expression and a lower tumor TIDE score, suggesting the potential for better immunotherapy outcomes. Additionally, scRNA-seq analysis revealed higher ITGA3 expression in tumor cells compared with normal hepatocytes. Wound healing scratch and transwell cell migration assays revealed that overexpression of the MBRG ITGA3 enhanced migration of HCC HepG2 cells.

CONCLUSION

This study established a direct molecular correlation between metastasis and BM, encompassing clinical features, tumor microenvironment, and immune response, thereby offering valuable insights for predicting clinical outcomes and immunotherapy responses in HCC.

Targeting PI3K/Akt signal transduction for cancer therapy

The phosphatidylinositol 3-kinase (PI3K)/Akt pathway plays a crucial role in various cellular processes and is aberrantly activated in cancers, contributing to the occurrence and progression of tumors. Examining the upstream and downstream nodes of this pathway could allow full elucidation of its function. Based on accumulating evidence, strategies targeting major components of the pathway might provide new insights for cancer drug discovery. Researchers have explored the use of some inhibitors targeting this pathway to block survival pathways. However, because oncogenic PI3K pathway activation occurs through various mechanisms, the clinical efficacies of these inhibitors are limited. Moreover, pathway activation is accompanied by the development of therapeutic resistance. Therefore, strategies involving pathway inhibitors and other cancer treatments in combination might solve the therapeutic dilemma. In this review, we discuss the roles of the PI3K/Akt pathway in various cancer phenotypes, review the current statuses of different PI3K/Akt inhibitors, and introduce combination therapies consisting of signaling inhibitors and conventional cancer therapies. The information presented herein suggests that cascading inhibitors of the PI3K/Akt signaling pathway, either alone or in combination with other therapies, are the most effective treatment strategy for cancer.

The interaction between dietary inflammatory index and 6 P21 rs2010963 gene variants in metabolic syndrome

BACKGROUND

The Vascular endothelial growth factor (VEGF) regulates endothelial cell proliferation, migration and angiogenesis, promotes vascular and capillary permeability and also is involved in inflammation. VEGF gene has been suggested to play an important role in the pathogenesis of metabolic syndrome. The aim of this study was to investigate the association between inflammatory potential of a diet and + 405 VEGF C/G (rs2010963) polymorphism and metabolic components in patients with metabolic syndrome.

METHODS

One hundred fifty patients with metabolic syndrome and fifty healthy individuals were enrolled. A semi-quantitative food-frequency questionnaire (FFQ) was used for dietary assessments and dietary inflammatory index (DII) calculation. Biochemical assays including fasting serum glucose (FSG), serum insulin, matrix metalloproteinase-3 (MMP-3), liver enzymes and lipid profile were measured. Polymerase chain reaction-restriction fragments length polymorphism (PCR-RFLP) method was used for the determination of gene polymorphism.

RESULTS

In the current study, patients with metabolic syndrome had higher serum low density lipoprotein (LDL) and lower high density lipoprotein (HDL) concentrations compared with healthy subjects. Patients with lower DII quartiles and lower inflammatory potential of the diet had lower waist to hip ratio (WHR) and lower diastolic blood pressure (DBP) compared with patients in higher DII quartiles (P < 0.05). Moreover, patients and healthy subjects in second quartile of DII had significantly higher aspartate aminotransferase (AST) and alanine aminotransferase (ALT) concentrations compared with subjects in the first quartile; also healthy subjects in third quartile had significantly higher triglyceride (TG) and total cholesterol (TC) concentrations compared with subjects in second quartile (P < 0.05). Among different genotypes of 6 P21 rs2010963 gene variants in patients with metabolic syndrome, CC genotype indicated the highest DII compared with other genotypes (P < 0.05).

CONCLUSION

The current study revealed the association between DII and metabolic risk factors of metabolic syndrome.

LEVEL OF EVIDENCE

Level III, case-control analytic study.

Fibroblast activation protein α-positive pancreatic stellate cells promote the migration and invasion of pancreatic cancer by CXCL1-mediated Akt phosphorylation

Background

Pancreatic stellate cells (PSCs) is a highly heterogeneic stroma cell population in pancreatic cancer tissue. Interaction between PSCs and pancreatic cancer cells has not been well elucidated. This research was aimed to study the relationship between fibroblast activation protein α (FAPα)-positive (FAPα+) PSCs and the pathological features and prognosis of pancreatic cancer. The effects and mechanisms of FAPα + PSCs in pancreatic cancer were also explored.

Methods

Tissue microarray analysis was used to detect FAPα expression in tumor and adjacent tissues. The relationship between FAPα expression and pancreatic pathological features and prognosis were analyzed. The effects of FAPα+ PSCs on the proliferation, migration and invasion of pancreatic cancer were detected in vitro and in vivo. A cytokine chip was used to detect the differential expression of cytokines in FAPα-positive (FAPα+) and FAPα-negative (FAPα-) PSCs. Phosphorylated tyrosine kinase receptors were detected by a human phosphotyrosine kinase receptor protein chip. The interaction between differential cytokine and tyrosine kinase receptors was detected by immunoprecipitation.

Results

Compared with the adjacent tissues, pancreatic cancer stromal tissues showed high FAPα expression. FAPα was mainly expressed in the PSCs. FAPα+ PSCs were associated with lymph node metastasis. Higher numbers of FAPα+ PSCs predicted shorter survival. Pancreatic cancer cells released TGFβ1 and induced PSCs to express FAPα. FAPα+ PSCs released the chemokine CXCL1 and promoted the phosphorylation of the tyrosine kinase receptors EphB1 and EphB3 in pancreatic cancer cells. CXCL1, EphrinB1, and EphrinB3 worked together to promote the migration and invasion of pancreatic cancer cells by Akt phosphorylation. Talabostat (PT100), an FAPα inhibitor, inhibited the roles of FAPα+ PSCs.

Conclusions

FAPα+ PSCs can promote the migration, invasion, and metastasis of pancreatic cancer by the Akt signaling pathway. This interaction of FAPα+ PSCs with pancreatic cancer cells may become a new strategy for the comprehensive treatment of pancreatic cancer.

Fangchinoline targets PI3K and suppresses PI3K/AKT signaling pathway in SGC7901 cells

Fangchinoline, an important compound in Stephania tetrandra S. Moore, as a novel antitumor agent, has been implicated in several types of cancers cells except gastric cancer. To investigate whether fangchinoline affects gastric cancer cells, we detected the signaling pathway by which fangchinoline plays a role in different human gastric cancer cells lines. We found that fangchinoline effectively suppressed proliferation and invasion of SGC7901 cell lines, but not MKN45 cell lines by inhibiting the expression of PI3K and its downstream pathway. All of the Akt/MMP2/MMP9 pathway, Akt/Bad pathway, and Akt/Gsk3β/CDK2 pathway could be inhibited by fangchinoline through inhibition of PI3K. Taken together, these results suggest that fangchinoline targets PI3K in tumor cells that express PI3K abundantly and inhibits the growth and invasive ability of the tumor cells.

Disruption of phosphoinositide-specific phospholipases Cγ1 contributes to extracellular matrix synthesis of human osteoarthritis chondrocytes

Osteoarthritis (OA) is a degenerative joint disease characterized by articular cartilage degradation including extracellular matrix (ECM) degradation and cell loss. It is known that phosphoinositide-specific phospholipase γ1 (PLCγ1) can trigger several signaling pathways to regulate cell metabolism. However, whether this kinase is expressive and active in human OA chondrocytes and its role in the pathological progression of OA have not been investigated. The current study was designed to investigate the PLCγ1 expression in human OA cartilage, and whether PLCγ1 was involved in the ECM synthesis had been further explored using cultured human OA chondrocytes. Our results indicated that PLCγ1 was highly expressed in human OA chondrocytes. In our further study using the cultured human OA chondrocytes, the results demonstrated that the disruption of PLCγ1 by its inhibitor, U73122, and siRNA contributed to the ECM synthesis of human OA chondrocytes through regulating the expression of ECM-related signaling molecules, including MMP-13, Col II, TIMP1, Sox-9, and AGG. Furthermore, PLCγ1/IP3/Ca2+/CaMK II signaling axis regulated the ECM synthesis of human chondrocytes through triggering mTOR/P70S6K/S6 pathway. In summary, our results suggested that PLC-γ1 activities played an important role in the ECM synthesis of human OA chondrocytes, and may serve as a therapeutic target for treating OA.

Src and fibroblast growth factor 2 independently regulate signaling and gene expression induced by experimental injury to intact articular cartilage

OBJECTIVE

To investigate whether cartilage injury activates protein tyrosine kinases distinct from fibroblast growth factor (FGF)-related signaling, and whether they contribute to injury-induced gene responses.

METHODS

Phosphokinases and protein tyrosine phosphorylation were assayed by Western blotting of cartilage lysates. Immunoprecipitation and Western blotting with 4G10 antibody and immunoprecipitation kinase assay were carried out. Tyrosine-phosphorylated proteins on silver-stained gels of injured cartilage lysates were identified by mass spectrometry. Messenger RNA induction in cartilage explants was assessed by quantitative reverse transcriptase-polymerase chain reaction.

RESULTS

Protein tyrosine phosphorylation occurred within seconds of injury to the surface of intact articular cartilage, as did activation of MAPKs and IKK. Activation did not reoccur upon reinjury of cultured explants. The prominent tyrosine-phosphorylated proteins focal adhesion kinase, paxillin, and cortactin were identified as substrates of Src family kinases. The Src family kinase inhibitor PP2 blocked injury-induced tyrosine phosphorylation. It did not prevent activation of the MAPKs and IKK but differentially inhibited 8 of 10 inflammatory response genes that were induced by injury. In contrast, FGF signaling blockade with PD173074 reduced all MAPK and IKK activation by ∼50% and inhibited a different subset of genes but had no effect on Src-like signaling.

CONCLUSION

Injury to the surface of intact articular cartilage activates Src-like kinases as well as MAPKs and IKK (implying NF-κB activation). FGF-2 contributes to MAPK/IKK activation but not to Src-like signaling, suggesting that the latter is a parallel pathway that also regulates the injury-induced inflammatory gene response.

[The study of PI3K/AKT pathway in lung cancer metastasis and drug resistance]

磷脂酰肌醇-3-激酶/丝苏氨酸蛋白激酶（phosphatidyl-inositol 3-kinase/serine-threonine kinase, PI3K/ AKT）信号通路是细胞内重要信号转导通路之一，通过影响下游多种效应分子的活化状态，在细胞内发挥抑制凋亡、促进增殖的关键作用，与人类多种肿瘤的发生发展密切相关。研究表明PI3K/AKT信号通路在恶性肿瘤细胞的增殖、血管新生和转移及对放化疗的拮抗中都起着重要作用。对PI3K/AKT信号通路的深入研究有望找到肿瘤预防和药物治疗的新靶点。本文简要介绍了PI3K/AKT信号通路的组成与功能调节，并着重阐述了其在肺癌转移和耐药中的作用。

Expression of platelet-derived growth factor ligand and receptor in cerebral arteriovenous and cavernous malformations

The aim of this study was to investigate the expression of platelet-derived growth factor (PDGF) ligands A and B and receptors α and β in cerebral arteriovenous and cavernous malformations. Fifteen arteriovenous malformation (AVM) and 15 cerebral cavernous malformation (CCM) tissue samples were immunostained for PDGF ligands A and B, PDGF receptors (PDGFR) α and β, and vascular endothelial growth factor. Tissues were compared in terms of expression levels within various vascular layers, and the results were confirmed using western blotting. AVM had higher levels of PDGF-A expression than CCM (p = 0.004, 0.009, 0.001, and 0.027, for endothelium, media, adventitia, and perilesional tissue, respectively) and western blotting showed that there was higher expression of PDGFR-α in AVM tissues. In contrast, CCM endothelium, media, and adventitia had higher PDGF-B expression compared with AVM (p = 0.007, 0.001, and 0.039, respectively). PDGFR-β expression was also significantly higher in the endothelium of CCM tissue (p = 0.007). Overexpression of PDGF ligands and receptors in AVM and CCM may mean that therapeutic strategies targeting the PDGF pathway could be useful in the treatment of these two malformations.

CREG inhibits migration of human vascular smooth muscle cells by mediating IGF-II endocytosis

We previously determined that the cellular repressor of E1A-stimulated genes, (CREG) plays a role in the maintenance of the mature phenotype of vascular smooth muscle cells (SMCs). This study aimed to identify the role of CREG in modulating the migration of SMCs. Recombinant virus-mediated CREG expression inhibited the cellular migration of cultured SMCs associated with down-regulated activity of matrix metalloproteinase-9 (MMP-9). In contrast, CREG knockdown via the retroviral transfer of short hairpin RNAs promoted cellular migration. Enzyme-linked immunosorbent assay and endocytosis analysis revealed that CREG knockdown attenuated the internalization and increased secretion of insulin-like growth factor (IGF)-II. Western blot analysis demonstrated that both phosphoinositide 3-kinase (PI3K) and phosphatase Akt were enhanced in CREG knockdown SMCs. Furthermore, the effect of CREG knockdown on SMC migration was abrogated in a dose-dependent manner by the addition of either IGF-II neutralizing antibody or the PI3K inhibitor, LY294002. These results indicate that the CREG knockdown-mediated increase in IGF-II secretion promoted cellular migration in SMCs via the PI3K/Akt signal pathway. Additionally, blockage of IGF-II binding to the mannose-6-phosphate/IGF-II receptor (M6P/IGF2R) by IGF2R antibody or recombinant IGF2R fragment attenuated the endocytosis of IGF-II in cells overexpressing CREG. This indicates that M6P/IGF2R is involved in the regulation of CREG-mediated IGF-II endocytosis. In summary, these data demonstrate for the first time that CREG plays a critical role in the inhibition of SMC migration, as well as maintaining SMCs in a mature phenotype. These results may provide a new therapeutic target for vascular disease associated with neointimal hyperplasia.

The genetic basis for altered blood vessel function in disease: large artery stiffening

The progressive stiffening of the large arteries in humans that occurs during aging constitutes a potential risk factor for increased cardiovascular morbidity and mortality, and is accompanied by an elevation in systolic blood pressure and pulse pressure. While the underlying basis for these changes remains to be fully elucidated, factors that are able to influence the structure and composition of the extracellular matrix and the way it interacts with arterial smooth muscle cells could profoundly affect the properties of the large arteries. Thus, while age and sex represent important factors contributing to large artery stiffening, the variation in growth-stimulating factors and those that modulate extracellular production and homeostasis are also being increasingly recognized to play a key role in the process. Therefore, elucidating the contribution that genetic variation makes to large artery stiffening could ultimately provide the basis for clinical strategies designed to regulate the process for therapeutic benefit.

Mitogen-activated protein kinase (MAPK) and phosphatidylinositol-3 kinase (PI3K) pathways differently regulate retinal pigment epithelial cell-mediated collagen gel contraction

Retinal pigment epithelial (RPE) cell-mediated extracellular matrix contraction is believed to contribute to developing proliferative vitreoretinopathy. It has been shown that platelet-derived growth factor (PDGF) and its intracellular signaling pathway, including mitogen-activated protein kinase (MAPK) and phosphatidylinositol-3 kinase (PI3K), are mainly involved in this process. The aim of this study is to investigate how these downstream signaling pathways are related to RPE-mediated collagen gel contraction. We performed the gel contraction assay to evaluate the effect of PDGF in cultured ARPE-19 cells under the presence or absence of PD98059, MAPK inhibitor or wortmannin, PI3K inhibitor. Experiments treated with neutralizing antibody for various subtypes of integrin were also performed and the effect on PDGF-induced gel contraction was investigated. Expression changes of integrin alpha1, alpha2 and beta1 after PDGF stimulation was evaluated using quantitative real-time PCR and flow cytometry. The results showed that PDGF up-regulated ARPE-19 cell-mediated gel contractile activity. PDGF-induced collagen gel contraction was attenuated under presence of PD98059, wortmannin, or neutralizing antibody for integrin alpha1, alpha2, or beta1, all of which are critical subset for binding with type I collagen. The expression of integrin alpha1 and alpha2 was increased after PDGF stimulation in both real-time PCR and flow cytometry, however beta1 expression was not increased. PD98059 significantly attenuated integrin alpha1 and alpha2 expressions. However, wortmannin did not have the same effect. In conclusion, PDGF promotes ARPE-19 cell-mediated gel contraction via both MAPK and PI3K. This was probably due to an increased expression of integrin alpha1 and alpha2, which is mediated by MAPK, but not by PI3K. PI3K may regulate collagen gel contraction by another mechanism other than the up-regulation of integrin expression.

Decreased Production of Collagen Type III in Cultured Smooth Muscle Cells from Varicose Vein Patients Is due to a Degradation by MMPs: Possible Implication of MMP-3

An alteration of extracellular matrix is involved in varicose veins. We have previously shown that collagen III production, but not its mRNA expression, is decreased in cultured smooth muscle cells (SMC) from varicose veins, involving an over-production of collagen I. In this study, the mechanisms involved in this collagen III reduction are explored. Steady state levels of collagen III mRNA and its ability to translate a protein were evaluated. Neither stability nor functionality of the alpha1(III) coding mRNA were affected in cells from varicose veins. Potential intracellular degradations of collagen III were investigated with inhibitors of intracellular proteases but the production was unaffected. The level of N-terminal propeptides of collagen III in the extracellular medium was determined and was similar in SMC from control and varicose veins. The stability of collagen III was determined by time-course experiments and a degradation of the protein was observed in cells from varicose veins. The production of collagen III was partially restored in cells from varicose veins in the presence of Marimastat, a matrix metalloproteinase (MMP) inhibitor. The mRNA expression and protein production of MMP3 were increased in cells from varicose veins. Fibronectin, a potential substrate of MMP3, was decreased in SMC from varicose veins. In conclusion, collagen III, and probably fibronectin, are degraded extracellularly in SMC from varicose veins by a mechanism involving MMPs, and maybe MMP3 by a direct or an indirect pathway. The degradation of collagen III and fibronectin may have repercussions for the mechanical properties of the venous wall.

Activation of MMP-2 in response to vascular injury is mediated by phosphatidylinositol 3-kinase-dependent expression of MT1-MMP

Phosphatidylinositol 3-kinase (PI3K) is required for smooth muscle cell (SMC) proliferation. This study reports that inhibitors of PI3K also prevent SMC migration and block neointimal hyperplasia in an organ culture model of restenosis. Inhibition of neointimal formation by LY-294002 was concentration and time dependent, with 10 muM yielding the maximal effect. Continuous exposure for at least the first 4-7 days of culture was essential for significant inhibition. To assess the role of matrix metalloproteinases (MMPs) in this process, we monitored MMP secretion by injured vessels in culture. Treatment with LY-294002 selectively reduced active MMP-2 in media samples according to zymography and Western blot analysis without concomitant changes in latent MMP-2. Parallel results with wortmannin indicate that MMP-2 activation is PI3K dependent. Previous research has shown a role for both furin and membrane-type 1 (MT1)-MMP (MMP-14) in the activation of MMP-2. The furin inhibitor decanoyl-Arg-Val-Lys-Arg-chloromethylketone did not prevent MMP-2 activation after balloon angioplasty. In contrast, balloon angioplasty induced a significant increase in the levels of MT1-MMP, which was suppressed by LY-294002. No change in MT1-MMP mRNA was observed with LY-294002, because equivalent amounts of this mRNA were present in both injured and noninjured vessels. These results implicate PI3K-dependent regulation of MT1-MMP protein synthesis and subsequent activation of latent MMP-2 as critical events in neointimal hyperplasia after vascular injury.

Elevated serum vascular endothelial growth factor is associated with visceral fat accumulation in human obese subjects

AIMS/HYPOTHESIS

Adipose tissue expresses some bioactive molecules, which may be involved in the development of obesity-associated metabolic disorders and cardiovascular diseases. Vascular endothelial growth factor (VEGF) an important angiogenic factor is implicated in normal and pathological vessel formation. The aim of this study is to investigate clinically the association between blood serum VEGF concentrations and body fat accumulation as well as distribution. The study also aims to show the effect of serum VEGF protein on gene expression of transcriptional factor E26 transformation-specific-1 (Ets-1) and matrix metalloproteinase (MMP)-3.

METHODS

Serum VEGF concentrations were measured in 38 overweight or obese subjects. Fat distribution in the abdominal subcutaneous as well as visceral fat areas was assessed by computed tomography scans at umbilical level. Furthermore, the changes of serum VEGF concentrations following body weight reduction therapy were analyzed in eight subjects recruited from the original pool of subjects. Semi-purified circulating VEGF proteins were obtained by heparin-sepharose and its biological activities were shown to alter gene expressions in human aortic endothelial cells.

RESULTS

Serum VEGF concentrations were positively correlated with BMI (r=0.433, p=0.007) and visceral fat area (r=0.488, p=0.002). Stepwise regression analysis showed the visceral fat area as the most important determinant factor for VEGF circulating levels. Following body weight reduction therapy, VEGF concentrations as well as visceral fat area were decreased. The serum semi-purified VEGF protein enhanced expressions of Ets-1 and MMP-3 in human aortic endothelial cells.

CONCLUSION/INTERPRETATION

Increased serum VEGF concentrations associated with visceral fat accumulation could influence vascular endothelial function.

Influence of inflammatory cytokines on arteriogenesis

Blood vessel growth after birth is limited to two major processes. Angiogenesis is the growth of new capillaries by sprouting or intussusception. The major stimulus for angiogenesis is ischemia. In contrast, arteriogenesis describes the remodeling and growth of collateral arteries from a preexisting arteriolar network. Arteriogenesis is induced after the occlusion of a major artery which induces hemodynamic and mechanical effects on the collateral vessel wall which occur with increasing blood flow velocity due to the low pressure at the reentrant site of the collateral vessel. A variety of different cytokines that act by stimulating endothelial and smooth muscle cell proliferation and migration or recruitment and activation of monocytes have been identified to stimulate angiogenesis and/or arteriogenesis (i.e., MCP-1, FGF-2, TGF-beta, VEGF, and GM-CSF). Several clinical trials have been published in that field to suggest the feasibility and safety of treatment with such cytokines or their genes. However, the results indicate that further studies are needed before proangiogenic and proarteriogenic therapies are ready for clinical application.