Transforming growth factor-beta1 induces microvascular abnormalities through a down-modulation of neural cell adhesion molecule in human hepatocellular carcinoma

Tumor suppressor CLCA1 inhibits angiogenesis via TGFB1/SMAD/VEGF cascade and sensitizes hepatocellular carcinoma cells to Sorafenib

BACKGROUND

Hepatocellular carcinoma (HCC) is a highly vascularized tumor with a poor prognosis. Novel vascular-related therapeutic targets and prognostic markers remain urgently needed.

AIMS

To investigate the role and mechanism of CLCA1 in hepatocellular carcinoma.

METHODS

Immunofluorescence, Co-immunoprecipitation and rescue experiment were used to determine the specific mechanisms of CLCA1. Chemosensitivity assay was used to measure the impact of CLCA1 on Sorafenib.

RESULTS

CLCA1 was dramatically downregulated in hepatocellular carcinoma cell lines and tissues. Ectopic expression of CLCA1 induced cell apoptosis and G0/G1 phase arrest while suppressed cell growth, inhibited migration and invasion, reversal of epithelial mesenchymal transition in vitro and reduced xenograft tumor growth in vivo. Mechanistically, CLCA1 could co-localize and interact with TGFB1, thereby suppressing HCC angiogenesis through the TGFB1/SMAD/VEGF signaling cascade in vitro and in vivo. Moreover, CLCA1 also enhanced the sensitivity of HCC cells to the first-line targeted therapy, Sorafenib.

CONCLUSION

CLCA1 sensitizes HCC cells to Sorafenib and suppresses hepatocellular carcinoma angiogenesis through downregulating TGFB1 signaling cascade. This newly identified CLCA1 signaling pathway may help guide the anti-angiogenesis therapies for hepatocellular carcinoma. We also support the possibility of CLCA1 being a prognostic biomarker for hepatocellular carcinoma.

Deciphering the role of transforming growth factor-beta 1 as a diagnostic-prognostic-therapeutic candidate against hepatocellular carcinoma

Transforming growth factor-beta (TGF-β) is a multifunctional cytokine that performs a dual role as a tumor suppressor and tumor promoter during cancer progression. Among different ligands of the TGF-β family, TGF-β1 modulates most of its biological outcomes. Despite the abundant expression of TGF-β1 in the liver, steatosis to hepatocellular carcinoma (HCC) progression triggers elevated TGF-β1 levels, contributing to poor prognosis and survival. Additionally, elevated TGF-β1 levels in the tumor microenvironment create an immunosuppressive stage via various mechanisms. TGF-β1 has a prime role as a diagnostic and prognostic biomarker in HCC. Moreover, TGF-β1 is widely studied as a therapeutic target either as monotherapy or combined with immune checkpoint inhibitors. This review provides clinical relevance and up-to-date information regarding the potential of TGF-β1 in diagnosis, prognosis, and therapy against HCC.

CD146+ Pericytes Subset Isolated from Human Micro-Fragmented Fat Tissue Display a Strong Interaction with Endothelial Cells: A Potential Cell Target for Therapeutic Angiogenesis

Pericytes (PCs) are mesenchymal stromal cells (MSCs) that function as support cells and play a role in tissue regeneration and, in particular, vascular homeostasis. PCs promote endothelial cells (ECs) survival which is critical for vessel stabilization, maturation, and remodeling. In this study, PCs were isolated from human micro-fragmented adipose tissue (MFAT) obtained from fat lipoaspirate and were characterized as NG2+/PDGFRβ+/CD105+ cells. Here, we tested the fat-derived PCs for the dispensability of the CD146 marker with the aim of better understanding the role of these PC subpopulations on angiogenesis. Cells from both CD146-positive (CD146+) and negative (CD146−) populations were observed to interact with human umbilical vein ECs (HUVECs). In addition, fat-derived PCs were able to induce angiogenesis of ECs in spheroids assay; and conditioned medium (CM) from both PCs and fat tissue itself led to the proliferation of ECs, thereby marking their role in angiogenesis stimulation. However, we found that CD146+ cells were more responsive to PDGF-BB-stimulated migration, adhesion, and angiogenic interaction with ECs, possibly owing to their higher expression of NCAM/CD56 than the corresponding CD146− subpopulation. We conclude that in fat tissue, CD146-expressing cells may represent a more mature pericyte subpopulation that may have higher efficacy in controlling and stimulating vascular regeneration and stabilization than their CD146-negative counterpart.

CD105: tumor diagnosis, prognostic marker and future tumor therapeutic target

Cancer is one of the diseases with the highest morbidity and mortality rates worldwide, and its therapeutic options are inadequate. The endothelial glycoprotein, also known as CD105, is a type I transmembrane glycoprotein located on the surface of the cell membranes and it is one of the transforming growth factor-β (TGF-β) receptor complexes. It regulates the responses associated with binding to transforming growth factor β1 egg (Activin-A), bone morphogenetic protein 2 (BMP-2), and bone morphogenetic protein 7 (BMP-7). Additionally, it is involved in the regulation of angiogenesis. This glycoprotein is indispensable in the treatment of tumor angiogenesis, and it also plays a leading role in tumor angiogenesis therapy. Therefore, CD105 is considered to be a novel therapeutic target. In this study, we explored the significance of CD105 in the diagnosis, treatment and prognosis of various tumors, and provided evidence for the effect and mechanism of CD105 on tumors.

EP3 Receptor Deficiency Improves Vascular Remodeling and Cognitive Impairment in Cerebral Small Vessel Disease

Aging and hypertension are major risk factors for cerebral small vessel disease (CSVD). Anti-hypertensive therapy has achieved effective; however, incomplete results in treating CSVD, suggesting the need for additional treatments. Targeting abnormal inflammatory responses has become a topic of research interest. Small artery remodeling is the main pathological feature of CSVD. Inhibition of the E-prostanoid 3 (EP3) receptor has been shown to attenuate vascular remodeling in peripheral organs; however, little is known about its role in CSVD. Therefore, we investigated whether the deletion of EP3 attenuates the development of CSVD in an animal model-- stroke-prone renovascular hypertensive rat (RHRsp). We found that the cerebral small arteries of RHRsp exhibited increased EP3 expression. Despite no alleviation of hypertension, the deletion of EP3 still attenuated the cerebral small artery remodeling of RHRsp, as evidenced by reduced overexpression of extracellular matrix (ECM) in the vessel. In vitro experiments indicated that EP3 deletion regulated the expression of ECM by downregulating TGF-β1/Smad signaling. Furthermore, the Morris water maze test and magnetic resonance test demonstrated that EP3 knockout attenuated cognitive impairment of the RHRsp, possibly through increased cerebral blood flow. Together, our results indicate that the deletion of EP3 attenuates vascular remodeling and vascular cognitive impairment induced by hypertension, and blockade of the EP3 receptor may be a promising strategy for the treatment of CSVD.

The Curious Case of the HepG2 Cell Line: 40 Years of Expertise

Liver cancer is the third leading cause of cancer death worldwide. Representing such a dramatic impact on our lives, liver cancer is a significant public health concern. Sustainable and reliable methods for preventing and treating liver cancer require fundamental research on its molecular mechanisms. Cell lines are treated as in vitro equivalents of tumor tissues, making them a must-have for basic research on the nature of cancer. According to recent discoveries, certified cell lines retain most genetic properties of the original tumor and mimic its microenvironment. On the other hand, modern technologies allowing the deepest level of detail in omics landscapes have shown significant differences even between samples of the same cell line due to cross- and mycoplasma infection. This and other observations suggest that, in some cases, cell cultures are not suitable as cancer models, with limited predictive value for the effectiveness of new treatments. HepG2 is a popular hepatic cell line. It is used in a wide range of studies, from the oncogenesis to the cytotoxicity of substances on the liver. In this regard, we set out to collect up-to-date information on the HepG2 cell line to assess whether the level of heterogeneity of the cell line allows in vitro biomedical studies as a model with guaranteed production and quality.

The Curious Case of the HepG2 Cell Line: 40 Years of Expertise

Liver cancer is the third leading cause of cancer death worldwide. Representing such a dramatic impact on our lives, liver cancer is a significant public health concern. Sustainable and reliable methods for preventing and treating liver cancer require fundamental research on its molecular mechanisms. Cell lines are treated as in vitro equivalents of tumor tissues, making them a must-have for basic research on the nature of cancer. According to recent discoveries, certified cell lines retain most genetic properties of the original tumor and mimic its microenvironment. On the other hand, modern technologies allowing the deepest level of detail in omics landscapes have shown significant differences even between samples of the same cell line due to cross- and mycoplasma infection. This and other observations suggest that, in some cases, cell cultures are not suitable as cancer models, with limited predictive value for the effectiveness of new treatments. HepG2 is a popular hepatic cell line. It is used in a wide range of studies, from the oncogenesis to the cytotoxicity of substances on the liver. In this regard, we set out to collect up-to-date information on the HepG2 cell line to assess whether the level of heterogeneity of the cell line allows in vitro biomedical studies as a model with guaranteed production and quality.

The Curious Case of the HepG2 Cell Line: 40 Years of Expertise

Liver cancer is the third leading cause of cancer death worldwide. Representing such a dramatic impact on our lives, liver cancer is a significant public health concern. Sustainable and reliable methods for preventing and treating liver cancer require fundamental research on its molecular mechanisms. Cell lines are treated as in vitro equivalents of tumor tissues, making them a must-have for basic research on the nature of cancer. According to recent discoveries, certified cell lines retain most genetic properties of the original tumor and mimic its microenvironment. On the other hand, modern technologies allowing the deepest level of detail in omics landscapes have shown significant differences even between samples of the same cell line due to cross- and mycoplasma infection. This and other observations suggest that, in some cases, cell cultures are not suitable as cancer models, with limited predictive value for the effectiveness of new treatments. HepG2 is a popular hepatic cell line. It is used in a wide range of studies, from the oncogenesis to the cytotoxicity of substances on the liver. In this regard, we set out to collect up-to-date information on the HepG2 cell line to assess whether the level of heterogeneity of the cell line allows in vitro biomedical studies as a model with guaranteed production and quality.

The expression of neural cell adhesion molecule and the microenvironment of pituitary neuroendocrine tumours

The neural cell adhesion molecule (NCAM) has previously been studied in pituitary neuroendocrine tumours (PitNETs), but its role in tumour biology and aggressiveness remains controversial, and its relationship with the tumour microenvironment remains unknown. We aimed to characterise NCAM expression in PitNETs, to correlate this with clinico-pathological features, and to assess the role of various microenvironment components on NCAM expression. NCAM and immune cells were investigated by immunohistochemistry in 16 human non-functioning-PitNETs (NF-PitNETs) and eight somatotrophinomas, including macrophages (CD68, CD163, HLA-DR), cytotoxic (CD8) and T helper (CD4) lymphocytes, regulatory T cells (FOXP3), B cells (CD20), and neutrophils (neutrophil elastase). Five normal pituitaries were included for comparison. The cytokine secretome from these PitNETs and from PitNET-derived tumour-associated fibroblasts (TAFs) were assessed on culture supernatants using a multiplex immunoassay panel. There were no significant NCAM expression differences between PitNETs and normal pituitary, and no difference between types of pituitary tumours (NF-PitNETs vs. somatotrophinomas). There was no association between NCAM expression and different clinico-pathological features, including cavernous sinus invasion and Ki-67, nor with serum hormone levels. NCAM immunoreactivity correlated negatively with PitNET-derived CXCL10 (rho = -0.417; p = .042) and CX3CL1 (rho = -0.423; p = .040) levels. NCAM immunoreactivity was negatively correlated with TAF-derived fibroblast growth factor (FGF)-2 (rho = -0.632; p = .009), but not with other TAF-derived cytokines. Within the PitNET cohort, there were no correlations between NCAM immunoreactivity and immune infiltrates or ratios, although, within NF-PitNETs, NCAM expression was higher in tumours with more FOXP3+ cells. NCAM expression does not differ between PitNETs and normal pituitary, and does not appear to relate to tumour invasiveness or proliferation. However, our data suggest a possible role for cytokines in the modulation of NCAM expression in PitNETs, particularly CXCL10, CX3CL1 and FGF-2, but not for immune cell infiltrates.

Role and clinical significance of TGF‑β1 and TGF‑βR1 in malignant tumors (Review)

The appearance and growth of malignant tumors is a complicated process that is regulated by a number of genes. In recent years, studies have revealed that the transforming growth factor-β (TGF-β) signaling pathway serves an important role in cell cycle regulation, growth and development, differentiation, extracellular matrix synthesis and immune response. Notably, two members of the TGF-β signaling pathway, TGF-β1 and TGF-β receptor 1 (TGF-βR1), are highly expressed in a variety of tumors, such as breast cancer, colon cancer, gastric cancer and hepatocellular carcinoma. Moreover, an increasing number of studies have demonstrated that TGF-β1 and TGF-βR1 promote proliferation, migration and epithelial-mesenchymal transition of tumor cells by activating other signaling pathways, signaling molecules or microRNAs (miRs), such as the NF-κB signaling pathway and miR-133b. In addition, some inhibitors targeting TGF-β1 and TGF-βR1 have exhibited positive effects in in vitro experiments. The present review discusses the association between TGF-β1 or TGF-βR1 and tumors, and the development of some inhibitors, hoping to provide more approaches to help identify novel tumor markers to restrain and cure tumors.

TGF-β1 rs1800469 gene polymorphism in the development of cirrhosis & hepatocellular carcinoma in Pakistani HCV patients

Hepatocellular carcinoma (HCC) has been increasing among Pakistani males. Aim: The main objective of this study was to evaluate the role of TGF-β-1 gene polymorphism as a risk factor in chronic hepatitis C virus (HCV) infected HCC patients in Pakistan. Patients & methods: A total of 286 subjects were recruited into three different groups (Group I: 96 healthy controls, Group II: 96 HCV, Group III: 94 HCC). Results: A significant increase in genotype and allele frequencies of TGF-β-1 gene was observed in HCC, HCV with OR = 1.9; 95% CI: 1.275–2.871; p > 0.05, OR = 1.6; 95% CI: 1.12–2.51; p > 0.05 and OR = 1.7; 95% CI: 1.036–1.923; p > 0.05. Conclusion: A higher frequency of the TT genotype and T allele of the TGF-β-1 gene is observed in Pakistani HCV and HCC patients.

Transforming growth factor-β1 and lysophosphatidic acid activate integrin β6 gene promoter in Hep-3B cells

Although it is difficult to detect αvβ6 integrin (αvβ6) in normal epithelia cells, its expression is upregulated during wound healing and carcinogenesis. Overexpression of αvβ6 has been demonstrated in epithelial cell carcinomas, such as adenocarcinoma of the colon and ovary. However, the expression of αvβ6 has not been reported in hepatocellular carcinoma (HCC). We previously indicated that LPA may induce αvβ6-mediated TGF-β1 signaling mechanisms during the pathogenesis of lung injury and fibrosis. In addition, transforming growth factor-β1 (TGF-β1) and lysophosphatidic acid (LPA) have been demonstrated to participate in the progression of HCC. In the present study, we hypothesized that TGF-β1 and LPA would serve a key role in the subunit integrin β6 (Itgβ6) transcriptional regulatory mechanism in HCC. It was identified that human HCC tissues and Hep-3B cells expressed Itgβ6. Treatment of Hep-3B with TGF-β1 or LPA increased the expression of Itgβ6. Furthermore, truncation experiments indicated a positive regulatory region at -326 to -157 bp of the Itgβ6 promoter. TGF-β1 and LPA increased transcriptional activation at this regulatory region. To the best of our knowledge, the present study was the first to demonstrate Itgβ6 expression in HCC, and the data indicate that TGF-β1 and LPA regulate Itgβ6 expression through the Itgβ6 gene promoter, which is an important factor in the development of HCC.

TGF-β1 signaling pathway serves a role in HepG2 cell regulation by affecting the protein expression of PCNA, gankyrin, p115, XIAP and survivin

The transforming growth factor-β (TGF-β) signaling pathway serves a key role in the pathogenesis of liver cancer. To investigate the association between TGF-β1 and the following proteins: Proliferating cell nuclear antigen (PCNA), gankyrin, general vesicular transport factor p115 (p115), X-linked inhibitor of apoptosis protein (XIAP) and survivin, HepG2 liver cancer cells were transfected with small interfering RNA (siRNA) directed against TGF-β1, or were treated with exogenous TGF-β1. TGF-β1 protein expression levels were assessed at 72 and 96 h using western blotting, cell growth was evaluated using a Cell Counting kit-8 assay, and flow cytometry was used to examine cell cycle distribution and apoptosis. In addition, PCNA, gankyrin, p115, XIAP and survivin protein levels were evaluated using western blotting. TGF-β1 protein expression levels were decreased at 72 and 96 h following siRNA transfection, indicating that the siRNA against TGF-β1 was effective. In the TGF-β1-knockdown group, the HepG2 cells exhibited G₁ or S-phase cell cycle arrest; therefore, the number of G₂-phase cells was decreased, cell growth was inhibited and apoptotic peaks were observed. By contrast, no significant alteration in cell cycle distribution or apoptosis was observed in the cells treated with exogenous TGF-β1. In the exogenous TGF-β1 group, PCNA and XIAP protein expression levels were increased, whereas gankyrin, p115 and survivin protein expression was observed to be dependent on the duration of treatment. By contrast, PCNA, gankyrin, XIAP and survivin protein expression decreased following TGF-β1 knockdown; however, p115 protein expression increased. In conclusion, the TGF-β1 signaling pathway may affect cell growth, cell cycle distribution and apoptosis through the regulation of PCNA, gankyrin, p115, XIAP and survivin protein expression in liver cancer. The results of the present study may improve the current understanding of the role of the TGF-β signaling pathway during the pathogenesis of liver cancer.

Identification of hub genes and pathways associated with hepatocellular carcinoma based on network strategy

The objective of this study was to identify hub genes and pathways associated with hepatocellular carcinoma (HCC) by centrality analysis of a co-expression network. A co-expression network based on differentially expressed (DE) genes of HCC was constructed using the Differentially Co-expressed Genes and Links (DCGL) package. Centrality analyses, for centrality of degree, clustering coefficient, closeness, stress and betweenness for the co-expression network were performed to identify hub genes, and the hub genes were combined together to overcome inconsistent results. Enrichment analyses were conducted using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes databases. Finally, validation of hub genes was conducted utilizing reverse transcription-polymerase chain reaction (RT-PCR) analysis. In total, 260 DE genes between normal controls and HCC patients were obtained and a co-expression network with 154 nodes and 326 edges was constructed. From this, 13 hub genes were identified according to degree, clustering coefficient, closeness, stress and betweenness centrality analysis. It was found that reelin (RELN), potassium voltage-gated channel subfamily J member 10 (KCNJ10) and neural cell adhesion molecule 1 (NCAM1) were common hub genes across the five centralities, and the results of RT-PCR analysis for RELN, KCNJ10 and NCAM1 were consistent with the centrality analyses. Pathway enrichment analysis of DE genes showed that cell cycle, metabolism of xenobiotics by cytochrome P450 and p53 signaling pathway were the most significant pathways. This study may contribute to understanding the molecular pathogenesis of HCC and provide potential biomarkers for its early detection and effective therapies.

Identification of hepatocellular carcinoma related genes with k-th shortest paths in a protein-protein interaction network

Hepatocellular carcinoma (HCC) is the most common type of liver cancer worldwide and one of the deadliest cancers in Asia. But at present, effective targets for HCC clinical therapy are still limited. The "guilt by association" rule suggests that interacting proteins share the same or similar functions and hence may be involved in the same pathway. This assumption can be used to identify disease related genes from protein association networks constructed from existing PPI data. Given the close association between Hepatitis B virus and Hepatitis B which may lead to HCC, here we develop a computational method to identify hepatocellular carcinoma related genes based on k-th shortest paths in the protein-protein interaction (PPI) network (we set k=1, 2 in this study). Finally, we found 33 genes whose p-values were less than 0.05, and most of them have been reported to be involved in HCC tumorigenesis and development. The results also provide a new reference for research into HCC oncogenesis and for development of new strategies for HCC clinical therapies.

Variations of circulating endothelial progenitor cells and transforming growth factor-beta-1 (TGF-β1) during thoracic radiotherapy are predictive for radiation pneumonitis

Background

The vascular endothelial cells are important targets of radiotherapy, which may be involved in the pathogenesis of radiation pneumonitis (RP). This study investigated the variations of circulating endothelial progenitor cells (EPCs) and transforming growth factor-beta-1 (TGF-β1) during three-dimensional conformal radiation therapy (3D-CRT) in patients with non–small-cell lung cancer (NSCLC) and analyzed the correlation between these variations with the occurrence of RP.

Patients and methods

From November 2008 to November 2009, eighty-four consecutive patients receiving 3D-CRT for stage III disease were evaluated prospectively. Circulating EPCs and TGF-β1 levels were measured at baseline, every 2 weeks during, and at the end of treatment. RP was evaluated prospectively at 6 weeks after 3D-CRT.

Results

Thirty-eight patients (47.5%) experienced score 1 or more of RP. The baseline levels of EPCs and TGF-β1 were analyzed, no difference was found between patients with and without RP during and after 3D-CRT. By serial measurement of TGF-β1 and EPCs levels, we found that the mean levels of EPCs in the whole population remained stable during radiotherapy, but the mean levels of TGF-β1 increased slowly during radiotherapy. TGF-β1 and EPCs levels were all significantly higher at week 2, week 4 and week 6 in patients with RP than that in patients without RP, respectively. During the period of radiation treatment, TGF-β1 levels began to increase in the first 2 weeks and became significantly higher at week 6 (P < 0.01). EPCs levels also began to increase in the first 2 weeks and reached a peak at week 4. Using an ANOVA model for repeated-measures, we found significant associations between the levels of TGF-β1 and EPCs during the course of 3D-CRT and the risk of developing RP (P < 0.01). Most of the dosimetric factors showed a significant association with RP.

Conclusion

Early variations of TGF-β1 and EPCs levels during 3D-CRT are significantly associated with the risk of RP. Variations of circulating TGF-β1 and EPCs levels during 3D-CRT may serve as independent predictive factors for RP.

Trial registration

Trials registration number: 20070618

Tumor markers for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors with a high rate of morbidity and mortality. HCC affects approximately one million individuals annually worldwide, with the incidence equal to the mortality rate. In 2008, HCC was listed as the third most lethal cancer. Thus, early diagnosis is crucial for improving the survival rate for patients. α-fetoprotein (AFP) together with iconography and pathology detection are commonly used in the clinical early diagnosis of liver cancer. However, the specificity and sensitivity of AFP used in screening for liver cancer are not satisfactory. Athough the development of molecular biology has led to the identification of new tumor markers, including proteantigens, cytokines, enzymes and isoenzymes, as well as related genes that can be used in the treatment and prognosis of liver cancer, more tumor markers are required for effective early diagnosis of diseases and monitoring of the curative effect.

Identification of the genes chemosensitizing hepatocellular carcinoma cells to interferon-α/5-fluorouracil and their clinical significance

The incidence of advanced hepatocellular carcinoma (HCC) is increasing worldwide, and its prognosis is extremely poor. Interferon-alpha (IFN-α)/5-fluorouracil (5-FU) therapy is reportedly effective in some HCC patients. In the present study, to improve HCC prognosis, we identified the genes that are sensitizing to these agents. The screening strategy was dependent on the concentration of ribozymes that rendered HepG2 cells resistant to 5-FU by the repeated transfection of ribozymes into the cells. After 10 cycles of transfection, which was initiated by 5,902,875 sequences of a ribozyme library, three genes including protein kinase, adenosine monophosphate (AMP)-activated, gamma 2 non-catalytic subunit (PRKAG2); transforming growth factor-beta receptor II (TGFBR2); and exostosin 1 (EXT1) were identified as 5-FU-sensitizing genes. Adenovirus-mediated transfer of TGFBR2 and EXT1 enhanced IFN-α/5-FU-induced cytotoxicity as well as 5-FU, although the overexpression of these genes in the absence of IFN-α/5-FU did not induce cell death. This effect was also observed in a tumor xenograft model. The mechanisms of TGFBR2 and EXT1 include activation of the TGF-β signal and induction of endoplasmic reticulum stress, resulting in apoptosis. In HCC patients treated with IFN-α/5-FU therapy, the PRKAG2 mRNA level in HCC tissues was positively correlated with survival period, suggesting that PRKAG2 enhances the effect of IFN-α/5-FU and serves as a prognostic marker for IFN-α/5-FU therapy. In conclusion, we identified three genes that chemosensitize the effects of 5-FU and IFN-α/5-FU on HCC cells and demonstrated that PRKAG2 mRNA can serve as a prognostic marker for IFN-α/5-FU therapy.