Identification of metastasis candidate proteins among HCC cell lines by comparative proteome and biological function analysis of S100A4 in metastasis in vitro

Prognostic value of S100A4 and Glypican-3 in hepatocellular carcinoma in cirrhotic HCV patients

AIMS

Both S100A4 and Glypican-3 have been known to be engaged in HCC development and progression. This study aimed to evaluate both S100A4 and GPC3 expression in HCC tissues as a prognostic markers.

METHODS

Tissues from 70 patients of HCC in cirrhotic HCV patients were evaluated by immunohistochemistry using antibodies against SA100A4 and GPC3 and compared with tumor-adjacent tissue (controls). All cases were followed for 40 months.

RESULTS

GPC3 was more expressed in HCC (79%) than S100A4 (21%). S100A4 was more significantly expressed in cases showing metastasis, microscopic vascular emboli, necrosis, and grade III tumors. There was no relationship between overall survival and both S100A4 and GPC3. The only significant independent predictor for recurrence was decompensation (OR 3.037), while metastasis was significantly predicted by S100A4 expression (OR 9.63) and necrosis (OR 8.33).

CONCLUSION

S100A4 might be used as a prognostic marker for HCC, while GPC3 is a reliable marker of HCC diagnosis.

S100 Proteins in Fatty Liver Disease and Hepatocellular Carcinoma

Non-alcoholic fatty liver disease (NAFLD) is a highly prevalent and slow progressing hepatic pathology characterized by different stages of increasing severity which can ultimately give rise to the development of hepatocellular carcinoma (HCC). Besides drastic lifestyle changes, few drugs are effective to some extent alleviate NAFLD and HCC remains a poorly curable cancer. Among the deregulated molecular mechanisms promoting NAFLD and HCC, several members of the S100 proteins family appear to play an important role in the development of hepatic steatosis, non-alcoholic steatohepatitis (NASH) and HCC. Specific members of this Ca²⁺-binding protein family are indeed significantly overexpressed in either parenchymal or non-parenchymal liver cells, where they exert pleiotropic pathological functions driving NAFLD/NASH to severe stages and/or cancer development. The aberrant activity of S100 specific isoforms has also been reported to drive malignancy in liver cancers. Herein, we discuss the implication of several key members of this family, e.g., S100A4, S100A6, S100A8, S100A9 and S100A11, in NAFLD and HCC, with a particular focus on their intracellular versus extracellular functions in different hepatic cell types. Their clinical relevance as non-invasive diagnostic/prognostic biomarkers for the different stages of NAFLD and HCC, or their pharmacological targeting for therapeutic purpose, is further debated.

MACROD2 deficiency promotes hepatocellular carcinoma growth and metastasis by activating GSK-3β/β-catenin signaling

Structural variations (SVs) influence the development and progression of multiple types of cancer. The genes affected by SVs in hepatocellular carcinoma (HCC) and their contribution to tumor growth and metastasis remain unknown. In this study, through whole-genome sequencing (WGS), we identified MACROD2 as the gene most frequently affected by SVs, which were associated with low MACROD2 expression levels. Low MACROD2 expression was predictive of tumor recurrence and poor overall survival. MACROD2 expression was decreased in HCC cell lines, especially those with high metastatic potential. MACROD2 knockdown in HCC cells markedly enhanced proliferation and invasiveness in vitro and tumor progression in vivo and promoted epithelial–mesenchymal transition (EMT). By contrast, MACROD2 overexpression reversed EMT and inhibited HCC growth and metastasis. Mechanistically, MACROD2 deficiency suppressed glycogen synthase kinase-3β (GSK-3β) activity and activated β-catenin signaling, which mediated the effect of MACROD2 on HCC. In clinical HCC samples, decreased MACROD2 expression was correlated with the activation of GSK-3β/β-catenin signaling and the EMT phenotype. Overall, our results revealed that MACROD2 is frequently affected by SVs in HCC, and its deficiency promotes tumor growth and metastasis by activating GSK-3β/β-catenin signaling.

Osterix promotes the migration and angiogenesis of breast cancer by upregulation of S100A4 expression

As a key transcription factor required for bone formation, osterix (OSX) has been reported to be overexpressed in various cancers, however, its roles in breast cancer progression remain poorly understood. In this study, we demonstrated that OSX was highly expressed in metastatic breast cancer cells. Moreover, it could upregulate the expression of S100 calcium binding protein A4 (S100A4) and potentiate breast cancer cell migration and tumor angiogenesis in vitro and in vivo. Importantly, inhibition of S100A4 impaired OSX-induced cell migration and capillary-like tube formation. Restored S100A4 expression rescued OSX-short hairpin RNA-suppressed cell migration and capillary-like tube formation. Moreover, the expression levels of OSX and S100A4 correlated significantly in human breast tumors. Our study suggested that OSX acts as an oncogenic driver in cell migration and tumor angiogenesis, and may serve as a potential therapeutic target for human breast cancer treatment.

LMO3 promotes hepatocellular carcinoma invasion, metastasis and anoikis inhibition by directly interacting with LATS1 and suppressing Hippo signaling

Background

In this research, we aimed to investigate the biological functions of LIM domain only 3 (LMO3) in hepatocellular carcinoma (HCC) and uncover the underlying molecular mechanism in it.

Methods

HCC tissue microarray (n = 180) was used to analyze the correlation between LMO3 expression and clinicopathological findings. In vitro transwell matrigel invasion assay and annexin V anoikis assay in HCC cells were conducted to investigate LMO3 related biological functions. In vivo intrahepatic and lung metastasis models were used to determine the role of LMO3 in HCC metastasis. Quantitative real-time PCR, western blotting and immunohistochemical staining were performed to investigate the expression and mechanism of LMO3 in HCC.

Results

We found that the expression of LMO3 was significantly upregulated in HCC tissues, and it was closely related to clinicopathological findings and patient prognoses. Knockdown of LMO3 suppressed the invasion and anoikis inhibition of HCC cells in vitro. Meanwhile, the metastasis of SMMC-7721 cells was also suppressed by LMO3 knockdown in vivo. Furthermore, we found that LMO3 knockdown increased the phosphorylation of YAP and LATS1, and decrease Rho GTPases activities. LMO3 directly interacted with LATS1, and thus suppressed Hippo signaling. Recombinant LMO3 (rLMO3) protein administration decreased the phosphorylation of YAP and LATS1, and increased Rho GTPases activities. The inhibitors of the Hippo pathway abrogated rLMO3 protein-induced HCC cell invasion and anoikis inhibition.

Conclusions

These results suggest that LMO3 promotes HCC cell invasion and anoikis inhibition by interacting with LATS1 and suppressing Hippo signaling. LMO3 may serve as a potential therapeutic target for HCC in future.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0903-3) contains supplementary material, which is available to authorized users.

Depletion of S100A4+ stromal cells does not prevent HCC development but reduces the stem cell-like phenotype of the tumors

There is a pressing need for the development of novel approaches to treat and prevent hepatocellular carcinoma (HCC). The S100 calcium-binding protein S100A4 is associated with poor prognosis and metastasis in several human cancers. In addition, a role for S100A4 in modulating cancer-initiating cells stemness properties was recently proposed in head and neck and gastric cancers. Whether S100A4⁺ stromal cells contribute to tumor onset remains, however, an unanswered question. To address that question, we generated a new mouse model allowing for the depletion of S100A4⁺ cells in a mouse model of HCC with stemness properties, by crossing mice with hepatic deletion of phosphatase and tensin homolog (PTEN) with mice expressing viral thymidine kinase under the control of S100A4 promoter. Depletion of S100A4⁺ cells by ganciclovir injection did not prevent the development of HCC but reduced the stemness phenotype of the tumor as measured by the expression of progenitor cell, biliary cell and hepatocyte markers. The results were further confirmed by histology analysis showing reduction of cholangiolar tumor components and degree of oval cell hyperplasia in the adjacent liver. Depletion of S100A4⁺ cells had also some beneficial effect on the underlying liver disease with a reduction of NAS score, largely due to the reduction of inflammation. In conclusion, this study demonstrated that S100A4⁺ cells do not contribute to HCC onset but maintain the stemness phenotype of the tumor. This study also suggests for the first time a crosstalk between inflammation and stemness.

NMI promotes hepatocellular carcinoma progression via BDKRB2 and MAPK/ERK pathway

Hepatocellular carcinoma (HCC) is one of the most prevalent and aggressive malignant tumors. The involvement of N-myc (and STAT) interactor (NMI) and its possible functional mechanisms in HCC progression still remain to be elucidated. In this study, we found that NMI was overexpressed in metastatic HCC cell lines compared with non-metastatic ones; and the expression levels of NMI in the HCC samples with metastasis were higher than that in the non-metastatic specimens. Furthermore, NMI depletion significantly decreased HCC cell proliferation and invasiveness in vitro, and also inhibited tumor growth and lung metastasis in vivo in nude mice models bearing human HCC. By contrast, NMI stable overexpression can enhance the malignant behaviors obviously. Moreover, we further verified that NMI promotes the expression of BDKRB2 and mediates the activation of MAPK/ERK signaling pathway according to the bidirectional perturbations of NMI expression in vivo or in vitro of HCC. Taken together, NMI is a pro-metastatic molecule and partially responsible for HCC tumor growth and motility. NMI could improve its downstream target BDKRB2 expression to induce ERK1/2 activation, and thereby further evoke malignant progression of HCC.

Palbociclib induces activation of AMPK and inhibits hepatocellular carcinoma in a CDK4/6-independent manner

Palbociclib, a CDK4/6 inhibitor, has recently been approved for hormone receptor‐positive breast cancer patients. The effects of palbociclib as a treatment for other malignancies, including hepatocellular carcinoma (HCC), are of great clinical interest and are under active investigation. Here, we report the effects and a novel mechanism of action of palbociclib in HCC. We found that palbociclib induced both autophagy and apoptosis in HCC cells through a mechanism involving 5′ AMP‐activated protein kinase (AMPK) activation and protein phosphatase 5 (PP5) inhibition. Blockade of AMPK signals or ectopic expression of PP5 counteracted the effect of palbociclib, confirming the involvement of the PP5/AMPK axis in palbociclib‐mediated HCC cell death. However, CDK4/6 inhibition by lentivirus‐mediated shRNA expression did not reproduce the effect of palbociclib‐treated cells, suggesting that the anti‐HCC effect of palbociclib is independent of CDK4/6. Moreover, two other CDK4/6 inhibitors (ribociclib and abemaciclib) had minimal effects on HCC cell viability and the PP5/AMPK axis. Palbociclib also demonstrated significant tumor‐suppressive activity in a HCC xenograft model, which was associated with upregulation of pAMPK and PP5 inhibition. Finally, we analyzed 153 HCC clinical samples and found that PP5 expression was highly tumor specific and was associated with poor clinical features. Taken together, we conclude that palbociclib exerted antitumor activity against HCC through the PP5/AMPK axis independent of CDK4/6. Our findings provide a novel mechanistic basis for palbociclib and reveal the therapeutic potential of targeting PP5/AMPK signaling with a PP5 inhibitor for the treatment of hepatocellular carcinoma.

Functional and clinical evidence that TAZ is a candidate oncogene in hepatocellular carcinoma

Transcriptional co-activator with PDZ-binding motif (TAZ) has been reported to be associated with carcinogenesis. However, the cellular function of TAZ in human hepatocellular carcinoma (HCC) remains elusive. In this study, an immunohistochemistry analysis revealed that the expression of TAZ in cancer tissue samples from 180 HCC patients was significantly higher than that in adjacent normal tissues. In addition, TAZ overexpression was significantly correlated with aggressive tumor characteristics such as tumor size, TNM stage, lymph node or distant metastasis, histological differentiation, and recurrent HCC (P < 0.05). The Kaplan-Meier test showed that TAZ-positive expression was related to a poor prognosis compared to TAZ-negative expression (P < 0.05). Furthermore, the expression level of TAZ was generally correlated with the invasiveness of cancer cells. The overexpression of TAZ in the Huh7 cell line, which endogenously expresses TAZ at low levels, significantly promoted cell proliferation, migration and invasion and inhibited apoptosis, whereas RNA interference-mediated knockdown of TAZ in the highly invasive cell line MHCC-97H significantly suppressed cell proliferation, migration and invasion in vitro and tumor formation in vivo.

Polycomb chromobox 4 enhances migration and pulmonary metastasis of hepatocellular carcinoma cell line MHCC97L

We recently report that the expression of polycomb chromobox 4 (Cbx4) is significantly correlated with the overall survival of a great cohort of hepatocellular carcinoma (HCC) patients and it enhances hypoxia-induced vascular endothelial growth factor (VEGF) expression and angiogenesis in HCC cells through enhancing sumoylation of hypoxia inducible factor-1alpha (HIF-1α). Here we continue to investigate the potential effects of Cbx4 on the migration and metastasis of the metastatic HCC cell line MHCC97L. Our results show that Cbx4 overexpression in the cell line increases the in vitro vessel formation of vascular endothelial cells in its SUMO interaction motifs-dependent manner, and promotes the in vitro migration of the cancer cell, which can be effectively abrogated by anti-VEGF antibody. Although Cbx4 expression does not impact the in vitro growth of MHCC97L cells, it still promotes the progression and metastasis of orthotopically transplanted tumors in nude mice. These results further support the role of Cbx4 as a SUMO E3 ligase in the progression and metastasis of HCC.

SERPINA5 inhibits tumor cell migration by modulating the fibronectin-integrin β1 signaling pathway in hepatocellular carcinoma

In our previous study, we identified 1241 loci with somatic copy number alterations in human hepatocellular carcinoma (HCC) using Affymetrix SNP 6.0 arrays, and a putative cancer gene SERPINA5 was uncovered in a novel chromosomal region with recurrent copy number loss at 14q31.1-32.13. The SERPINA5 was reported to be deregulated in renal, breast, prostate and ovarian cancers. However, the roles of SERPINA5 in cancer remain greatly elusive. In this study, we found that the DNA dosage and expression level of the SERPINA5 gene were significantly decreased in HCC by quantitative real-time PCR. Notably, the expression levels of SERPINA5 negatively correlated with malignant progression of HCC. The SERPINA5 gene was further observed to reduce in vitro and in vivo metastatic potential of HCC cells. Moreover, secreted SERPINA5 protein also could inhibit the metastatic ability of HCC cells. Finally, we discovered that one of the mechanisms explaining SERPINA5 inhibition of HCC metastasis is through direct interaction with fibronectin and disruption of the fibronectin-integrin signaling pathway. These findings highlight an important role of SERPINA5 in the regulation of migratory and metastatic potentials of HCC and suggest a potential application of SERPINA5 in cancer treatment.

Amplification of MPZL1/PZR promotes tumor cell migration through Src-mediated phosphorylation of cortactin in hepatocellular carcinoma

We have previously identified 1 241 regions of somatic copy number alterations (CNAs) in hepatocellular carcinoma (HCC). In the present study, we found that a novel recurrent focal amplicon, 1q24.1-24.2, targets the MPZL1 gene in HCC. Notably, there is a positive correlation between the expression levels of MPZL1 and intrahepatic metastasis of the HCC specimens. MPZL1 can significantly enhance the migratory and metastatic potential of the HCC cells. Moreover, we found that one of the mechanisms by which MPZL1 promotes HCC cell migration is by inducing the phosphorylation and activation of the pro-metastatic protein, cortactin. Additionally, we found that Src kinase mediates the phosphorylation and activation of cortactin induced by MPZL1 overexpression. Taken together, these findings suggest that MPZL1 is a novel pro-metastatic gene targeted by a recurrent region of copy number amplification at 1q24.1-24.2 in HCC.

Vascular endothelial cells facilitated HCC invasion and metastasis through the Akt and NF-κB pathways induced by paracrine cytokines

Background

It is well documented that cancer cells secrete angiogenic factors to recruit and sustain tumor vascular networks. However, little is known about the effects of endothelial cells on the behavior of tumor cells. The study here was to determine the roles of endothelial cells in HCC cell growth, migration and invasion.

Methods

A mixture of highly metastatic MHCC97H cells and HUVEC cells, as well as MHCC97H cells alone were subcutaneously injected into nude mice to observe the effects of HUVECs on HCC growth. The biological characteristics of MHCC97H cells respectively treated with conditioned medium (CM) derived from HUVECs and endothelial cell basal medium (EBM) in vitro, such as proliferation, migration and invasion, invasion/metastasis associated gene expression, were comparatively analyzed. Differential cytokines between CM and EBM were screened and identified using human cytokine array. Effects of the interested differential cytokine CCL2, IL-8 and CXCL16 and its related signaling pathways were further investigated in HCC cells.

Results

Subcutaneous tumorigenicity of MHCC97H cells in nude mice was promoted by HUVECs and its invasion/metastasis associated genes were significantly upregulated. The in vitro, proliferation, migration and invasion of HCC cells treated with CM were all significantly enhanced as compared to those with EBM stimulation. Simultaneously, PI3K/Akt and ERK1/2 pathway in HCC cells were activated by CM. Total of 25 differential cytokines were identified between CM and EBM such as angiopoietin-2, CCL2 (MCP-1), uPA, endostatin, CXCL16, IL-8, pentraxin 3 etc. The selected differential cytokines CCL2, IL-8 and CXCL16 all modulated the expressions of HCC invasion/metastasis genes, especially MMP2 and MMP9. In exposure to CCL2 or CXCL16 alone, upregulation in AKT phosphorylation but no change in ERK phosphorylation were found in MHCC97H cells, moreover the contents of nuclear transcription factor NF-κB were increased as compared to the control. However, no effects on the activation of Akt and ERK pathway in MHCC97H were found in exposure to IL-8.

Conclusion

This study expands the contribution of endothelial cells to the progression of HCC. It unveils a new paradigm in which endothelial cells function as initiators of molecular crosstalks that enhance survival, migration and invasion of HCC cells.

Aberrant expression of S100A6 and matrix metalloproteinase 9, but not S100A2, S100A4, and S100A7, is associated with epidermal carcinogenesis

BACKGROUND

S100 proteins belong to a family of calcium-binding proteins that regulate cell proliferation and differentiation. Despite our growing knowledge about the biology of S100 proteins in some human cancers, little is known about the expression of S100 family members in epidermal tumors and their clinical significance.

OBJECTIVE

To determine the expression of S100A2, S100A4, S100A6, S100A7, as well as matrix metalloproteinases 9 (MMP9) in a spectrum of epidermal tumors with benign and malignant characteristics.

METHODS

Immunohistological staining was performed for S100A2, S100A4, S100A6, S100A7, and MMP9 in 101 cases of various types of epidermal tumors, viz., squamous cell carcinoma (SCC), Bowen's disease (BD), actinic keratosis (AK), basal cell carcinoma (BCC), keratoacanthoma (KA), and seborrheic keratosis (SK). Thirteen specimens of normal skin (NS) served as control.

RESULTS

S100A2, S100A6, and S100A7 positive immunostaining was variably observed in different epidermal tumors. S100A4 staining was not observed in any epidermal tumors, but was clearly visible in dendritic cells. MMP9 immunostaining was positive only in 22/26 (84.62%) of SCC and 2/15 (13.33%) of BD cases. Expression of S100A2, S100A6, and S100A7 was increased in tumor cells compared to NS. However, only S100A6 expression was significantly associated with malignant transformation of epidermal tumors. Moreover, S100A6 expression was correlated with MMP9 expression in metastatic SCC.

CONCLUSIONS

Epidermal tumors show increased expression of S100A2 and S100A7 proteins. S100A4 may be a useful and distinct marker for epidermal dendritic cells. Expression of S100A6 and MMP9 in combination is associated with the development of SCC.

Metastasin leads to poor prognosis of hepatocellular carcinoma through partly inducing EMT

Hepatocellular carcinoma (HCC) is a common malignant cancer worldwide characterized by high metastatic potential and poor prognosis following radical resection. Metastasin is a Ca(2+)-binding protein associated with tumor metastasis. However, the expression and function of metastasin remain unknown. In the present study, we found that the expression of metastasin was upregulated in HCC tissues and positively correlated with poor prognosis following radical resection. Ectopic expression of metastasin in vitro induced typical epithelial-mesenchymal transition (EMT) in Hep3B cells including higher capacity of both migration and invasion, increased expression of both Vimentin and N-cadherin and decreased expression of E-cadherin. Knockdown of metastasin produced the opposite results in MHCC97H cells, which indicates that metastasin promotes HCC progression via induction of EMT. SNAI1 expression was upregulated by enforced expression of metastasin and, consequently, suppressing upregulation of SNAI1 secondary to metastasin overexpression abolished EMT. Collectively, the present results suggest that metastasin leads to HCC EMT partly through upregulating SNAI1 and contributes to poor prognosis following radical liver resection.

S100 proteins as diagnostic and prognostic markers in colorectal and hepatocellular carcinoma

CONTEXT

Clinical and experimental studies have suggested a link between S100 gene ex-pression and neoplastic disorders, however, the molecular mechanisms of this associa-tion are not well understood. The aim of this review was to conduct a comprehensive literature search in order to understand the possible underlying molecular mechanisms of this association. We also discuss their application as diagnostic and prognostic mark-ers in colorectal and hepatocellular carcinoma.

EVIDENCE ACQUISITIONS

We searched Pubmed (NLM) and Web of Science (ISI Web of Knowledge).

RESULTS

S100 genes display a complex expression pattern in colorectal and hepatocel- lular carcinoma. They are expressed in tumor and/or tumor stroma cells, and they exert both pro- and antitumorigenic actions. In view of this complexity, it becomes clear that S100 proteins might act as both friend and foe. The biological role of the S100 genes is predicted to depend on the relative contributions of the different cell types at specific stages of tumor progression.

CONCLUSIONS

Further research is required in order to uncover the functional role of S100 genes in tumorigenesis. Answers to this issue are needed before we can more fully un-derstand the clinical relevance of S100 protein expression within epithelial tumors, with regard to their potential applicability as biomarkers for diagnosis and therapy decisions.

Proteomic and systems biology analysis of monocytes exposed to securinine, a GABA(A) receptor antagonist and immune adjuvant

Securinine, a GABA(A) receptor antagonist, has been reported to enhance monocyte cell killing of Coxiella burnetii without obvious adverse effects in vivo. We employed multiplex 2D gel electrophoresis using Zdyes, a new generation of covalently linked fluorescent differential protein detection dyes to analyze changes in the monocyte proteome in response to Securinine. Securinine antagonism of GABA(A) receptors triggers the activation of p38. We used the differential protein expression results to guide a search of the literature and network analysis software to construct a systems biology model of the effect of Securinine on monocytes. The model suggests that various metabolic modulators (fatty acid binding protein 5, inosine 5'-monophosphate dehydrogenase, and thioredoxin) are at least partially reshaping the metabolic landscape within the monocytes. The actin bundling protein L-plastin, and the Ca(2+) binding protein S100A4 also appear to have important roles in the immune response stimulated by Securinine. Fatty acid binding protein 5 (FABP5) may be involved in effecting lipid raft composition, inflammation, and hormonal regulation of monocytes, and the model suggests that FABP5 may be a central regulator of metabolism in activated monocytes. The model also suggests that the heat shock proteins have a significant impact on the monocyte immune response. The model provides a framework to guide future investigations into the mechanisms of Securinine action and with elaboration may help guide development of new types of immune adjuvants.

Decreased selenium-binding protein 1 enhances glutathione peroxidase 1 activity and downregulates HIF-1α to promote hepatocellular carcinoma invasiveness

PURPOSE

We aimed to characterize the role of selenium-binding protein 1 (SBP1) in hepatocellular carcinoma (HCC) invasiveness and underlying clinical significance.

EXPERIMENTAL DESIGN

SBP1 expression was measured in stepwise metastatic HCC cell lines by Western blotting. The role of SBP1 in HCC was investigated using siRNA. Immunofluorescence analyses were used to detect the interaction between SBP1 and glutathione peroxidase 1 (GPX1). Nineteen fresh tumor tissues and 323 paraffin-embedded samples were used to validate in vitro findings and to detect the prognostic significance of SBP1, respectively.

RESULTS

Inhibition of SBP1 effectively increased cell motility, promoted cell proliferation, and inhibited apoptosis only under oxidative stress; it also greatly enhanced GPX1 activity without altering GPX1 expression and downregulated hypoxia-inducible factor-1α (HIF-1α) expression. SBP1 and GPX1 formed nuclear bodies and colocalized under oxidative stress. In freshly isolated clinical HCC tissues, decreased SBP1 was linked with increased GPX1 activity and correlated with vascular invasion. Tumor tissue microarrays indicated that SBP1 was an independent risk factor for overall survival and disease recurrence; patients with lower SBP1 expression experienced shorter overall survival periods and higher rates of disease recurrence (P < 0.001). Further analyses indicated that the predictive power of SBP1 was more significant for patients beyond the Milan criteria than patients within the Milan criteria.

CONCLUSIONS

Decreased expression of SBP1 could promote tumor invasiveness by increasing GPX1 activity and diminishing HIF-1α expression in HCC; SBP1 could be a novel biomarker for predicting prognosis and guiding personalized therapeutic strategies, especially in patients with advanced HCC.

Identification of transaldolase as a novel serum biomarker for hepatocellular carcinoma metastasis using xenografted mouse model and clinic samples

Hepatocellular carcinoma (HCC) is one of serious disorders with the highest morbidities and mortalities worldwide. Metastasis is the major concern that causes death in HCC. The goal of this study was to screen and identify potential serum proteins indicating HCC metastasis. Serum samples collected from control and HCCLM3-R metastatic HCC tumor model at specific stages of metastasis (1 wk, 3 wks and 6 wks) were subjected to iTRAQ labeling followed by 2DLC-ESI-MS/MS analysis. A total of 554 proteins were identified and 80 proteins were differential expressed at least between one adjacent time points. Among them, expression level of transaldolase (TALDO) was validated in mouse and human serum. The level of TALDO protein was found to be higher in metastatic mice serum compared to that of non-metastatic mice. Human specific TALDO was then identified in mouse serum through human specific peptides. Immunohistochemical and western blot analysis showed that the expression of TALDO in human HCC tissues and HCC cell lines was associated with its metastatic behavior. Subsequent screening of TALDO expression in 72 clinical serum samples (comprising 36 non-metastatic HCC and 36 metastatic HCC samples) revealed higher TALDO level in the serum of metastatic HCC patients. A receiver operating characteristic (ROC) curve estimated a maximal sensitivity of 77.8% and 86.1% specificity for TALDO in detection of HCC metastasis. The present results demonstrated that the nude mouse xenograft model is an efficient system for performing metastasis-related biomarker discovery. TALDO may be useful biomarkers for the detection of HCC metastasis.

A three-dimensional cell biology model of human hepatocellular carcinoma in vitro

We established an in vitro 3-D model of metastatic hepatocellular carcinoma (HCC) by culturing MHCC97H cells on molecular scaffolds within a rotating wall vessel bioreactor. Morphological and biochemical analyses revealed that the 3-D HCC model mirrored many clinical pathological features of HCC in vivo, including cancer cell morphology, tissue ultrastructure, protein production and secretion, glucose metabolism, tissue-specific gene expression, and apoptosis. Xenografts into livers of nude mice resulted in tumorigenesis and distant metastasis. This 3-D HCC spheroid is a promising model for HCC tumor biology, anticancer drug screening, and for the establishment of HCC animal models.

Up-regulation of Krüppel-like factor 8 promotes tumor invasion and indicates poor prognosis for hepatocellular carcinoma

BACKGROUND & AIMS

The transcription factor Krüppel-like factor 8 (KLF8) has a role in tumor development, growth, and metastasis, but its role in hepatocellular carcinoma (HCC) is not clear.

METHODS

KLF8 expression in human HCC cell lines and tumor tissues was measured by quantitative real-time polymerase chain reaction, immunoblot, and immunochemical analyses. The effects of KLF8 depletion or overexpression in HCC cells were observed in cultured cells and in mice. Changes in gene expression patterns in HCC cells in which levels of KLF8 were reduced using small interfering RNA were investigated by microarray analysis. The clinical significance of KLF8 expression levels were validated using tissue microarray analysis of surgical samples from 314 HCC patients.

RESULTS

KLF8 was overexpressed in highly metastatic HCC cell lines and in samples from patients with recurrent HCC. In cultured cells, KLF8 up-regulation promoted cell proliferation and invasion; inhibited apoptosis; down-regulated N-cadherin, vimentin, and fibronectin; and up-regulated E-cadherin. In mice, overexpression of KLF8 increased HCC progression and metastasis. Microarray analysis showed that reduction of KLF8 in HCC cells down-regulated expression of multiple genes involved in tumor progression and metastasis. KLF8 expression was a significant predictor of overall survival (P = .040) and time to HCC recurrence (P = .006) and was associated with early tumor recurrence (P = .001).

CONCLUSIONS

KLF8 promotes HCC cell proliferation and invasion, inhibits apoptosis, and induces the epithelial-to-mesenchymal transition. KLF8 up-regulation might be used to indicate poor prognosis or early recurrence of cancer in patients who have had surgery for HCC.

Expression and prognostic significance of osteopontin and caspase-3 in hepatocellular carcinoma patients after curative resection

Osteopontin (OPN) plays an important role in the development, invasion, and metastasis of malignancies. Recently, several studies have reported that OPN enhances chemoresistance in small-cell lung cancer and breast cancer by blocking caspase-9 and caspase-3-dependent cell apoptosis. The aim of this study was to assess the value of OPN and caspase-3 for predicting tumor recurrence after curative resection in hepatocellular carcinoma (HCC) patients. We found that OPN expression increased concordantly with increasing metastatic potential in human HCC cell lines, whereas caspase-3 expression declined. In a tumor tissue microarray immunohistochemical analysis, we found that patients with higher levels of OPN and lower levels of caspase-3 had a significantly poorer prognosis than patients with lower OPN and higher caspase-3 levels. The combination of OPN and caspase-3 expression thus served as an effective prognosticator. These findings suggest that OPN alone or in combination with caspase-3 may act as an independent indicator for HCC patients after curative resection.

Nanozeolite-driven approach for enrichment of secretory proteins in human hepatocellular carcinoma cells

Given the importance of secreted proteins as a source for early detection and diagnosis of disease, secreted proteins have been arousing considerable attention. However, the analysis of secreted proteins represents a challenge for current proteomic techniques. One of the difficulties in secretomic study is to concentrate proteins from large volume of growth media, particularly, the low abundant and low molecular weight proteins (molecular weight <30 kDa). Herein, we describe a novel strategy for harvesting secretory proteins. In this approach, proteins secreted from the human hepatocellular carcinoma cell line were enriched by zeolite LTL nanocrystals, followed by 1-D SDS-PAGE for protein fractionation and then by LC-ESI-MS/MS for protein identification. In total, 1474 unique proteins were confidently identified, including 505 low molecular weight proteins, and covered a broad range of pI and molecular weight. Furthermore, this study not only offered an efficient and powerful method for the enrichment of secretory proteins but also allowed in-depth study of secretome of hepatocellular carcinoma cells. The reported work is expected to represent one of the most comprehensive secretomic analyses so far.

Protein profile in HBx transfected cells: a comparative iTRAQ-coupled 2D LC-MS/MS analysis

The x protein of HBV (HBx) has been involved in the development of hepatocellular carcinoma (HCC), with a possible link to individual genotypes. Nevertheless, the underlying mechanism remains obscure. In this study, we aim to identify the HBx-induced protein profile in HepG2 cells by LC-MS/MS proteomics analysis. Our results indicated that proteins were differentially expressed in HepG2 cells transfected by HBx of various genotypes. Proteins associated with cytoskeleton were found to be either up-regulated (MACF1, HMGB1, Annexin A2) or down-regulated (Lamin A/C). These may in turn result in the decrease of focal adhesion and increase of cell migration in response to HBx. Levels of other cellular proteins with reported impact on the function of extracellular matrix (ECM) proteins and cell migration, including Ca(2+)-binding proteins (S100A11, S100A6, and S100A4) and proteasome protein (PSMA3), were affected by HBx. The differential protein profile identified in this study was also supported by our functional assay which indicated that cell migration was enhanced by HBx. Our preliminary study provided a new platform to establish a comprehensive cellular protein profile by LC-MS/MS proteomics analysis. Further downstream functional assays, including our reported cell migration assay, should provide new insights in the association between HCC and HBx.

JNK1 activation predicts the prognostic outcome of the human hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide with an extremely poor prognosis. The classification of HCC based on the molecular signature is not well-established.

RESULTS

In the present study, we reported HCC signature genes based on the JNK1 activation status in 31 HCC specimens relative to the matched distal noncancerous liver tissue from 31 patients. The HCCs with high JNK1 (H-JNK1) and low JNK1 (L-JNK1) were sub-grouped. Two different signature gene sets for both H-JNK1 and L-JNK1 HCC were identified through gene expression profiling. A striking overlap of signature genes was observed between the H-JNK1 HCC and the hepatoblastoma or hepatoblastoma-type HCC. Many established biomarkers for hepatic progenitor cells were over-expressed in H-JNK1 HCC, including AFP, TACSTD1, KRT19, KRT7, THY1, and PROM1. In addition, the majority of the most up-regulated genes were those associated with metastasis and earlier recurrence, whereas the genes for normal liver function were substantially down-regulated in H-JNK1 HCC tissue. A Kaplan-Meier plot demonstrated that the survival of the patients with H-JNK1 HCC was severely impaired.

CONCLUSION

Accordingly, we believe that the H-JNK1 HCC may originate from hepatic progenitor cells and is associated with poorer prognosis. The status of JNK1 activation in HCC tissue, thus, might be a new biomarker for HCC prognosis and therapeutic targeting.

Application of proteomics in the study of digestive system tumors

Proteomics is the study of all proteins present in a given organism, tissue, cell, and even organelle. Two-dimensional gel electrophoresis and mass spectrography are two core technologies in proteomics. Proteomic studies can help us understand the life as a whole. As a new platform for tumor research, proteomics is of important significance for early diagnosis, biomarker discovery, therapy and discovery of novel drug targets for esophageal carcinoma, gastric cancer, liver cancer, pancreatic cancer and colorectal cancer. Thus, it has potential broad application prospects.

JNK1, a potential therapeutic target for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the third leading cause of cancer death worldwide. Despite tremendous efforts to diagnose and institute new treatment regimens, the prognosis is still extremely poor. Therefore, knowledge of the molecular mechanisms governing the initiation, maintenance and progression of HCC is urgently needed. Recently, several groups have attributed an important role for c-Jun N-terminal kinase 1 (JNK1) in the pathogenesis of human HCC and its close association with the expression of HCC signature genes. In this review the various associations between JNK1 and HCC are discussed with the hope that targeting this pivotal kinase may lead to novel therapeutic approaches for this fatal disease.

Profiling distinct mechanisms of tumour invasion for drug discovery: imaging adhesion, signalling and matrix turnover

Recent advances in microscopic imaging technology, fluorescent reporter reagents, 3-dimensional (3D) cell models and multiparametric image analysis have enhanced our ability to model and understand complex cell physiology. Extension of these approaches to live cell, kinetic studies allows further spatial and temporal understanding of a multitude of dynamic functional events, including tumour cell invasion. Recent in vivo and 3D in vitro studies reveal how tumour cells utilize a diverse variety of mechanisms to permit invasion through 3D tissue environments. Such high degrees of diversity and plasticity between invasion mechanisms present a significant challenge to the successful treatment of malignant cancer. This review examines how advances in time-resolved imaging has contributed to the characterization of distinct modes of invasion and their associated molecular mechanisms. Specifically, we highlight the development of fluorescent reporter molecules and their incorporation into more predictive 3D in vitro and in vivo models, to enhance mechanistic analysis of tumour invasion. We also highlight the latest advances in kinetic imaging instrumentation applicable to in vitro and in vivo models of tumour invasion. We discuss how multiparametric image analysis can be used to interpret image data generated by these approaches. We further discuss how these approaches can be integrated into drug discovery pipelines to facilitate evaluation and selection of candidate drugs and novel pharmaceutical compositions, targeting multiple invasive mechanisms.

Cytokeratin 10 and cytokeratin 19: predictive markers for poor prognosis in hepatocellular carcinoma patients after curative resection

PURPOSE

Cytokeratin 10 (CK10) was found to be expressed differently in human hepatocellular carcinoma (HCC) cell lines with different metastatic potentials in our previous research. The aim of this study was to assess the value of CK10 alone or in combination with cytokeratin 19 (CK19) in predicting tumor recurrence after curative resection in HCC patients.

EXPERIMENTAL DESIGN

CK10 expression in stepwise metastatic HCC cell lines and tumor tissues from 50 HCC patients was investigated using immunofluorescence assay, quantitative real-time reverse transcription-PCR, and Western blot analyses. Tumor tissue microarrays of 300 HCC patients who underwent curative resection between 1997 and 2000 were used to detect the expressions of CK10 and CK19. Clinicopathologic data for these patients were evaluated. The prognostic significance was assessed using Kaplan-Meier survival estimates and log-rank tests.

RESULTS

CK10 was overexpressed in the high metastatic HCC cell line and in tumor tissues of recurrent patients. Both univariate and multivariate analyses revealed that CK10 was a significant predictor for overall survival (OS) and disease-free survival, and that CK19 was a significant predictor for OS. CK10 expression was correlated with poor prognosis regardless of alpha-fetoprotein, tumor-node-metastasis stage, and vascular invasion. The 7-year OS and disease-free survival rates in CK10+ and/or CK19+ patients were 30.0% and 37.6%, respectively, which were significantly lower than that of CK10-/CK19- patients (56.1% and 60.0%, respectively; P < 0.001).

CONCLUSION

CK10 is associated with HCC invasiveness. CK10 alone, or in combination with CK19, can be a novel predictor for poor prognosis of HCC patients after curative resection.

Advance in proteomic study of hepatocellular carcinoma

At present, studies of hepatocellular carcinoma focus on investigating the molecular mechanism of carcinogenesis, development, metastasis and reccurrence and seeking biological markers for early diagnosis and metastasis prediction and targets for interfering therapy. In the post-genome era, proteomics provides novel insights into the research of hepatocellular carcinoma, which is controlled by multi-genes and multi-proteins. In this paper we reviewed the recent progress in proteomic study of hepatocellular carcinoma.

Dysregulation of matrix metalloproteinases and their tissue inhibitors by S100A4

The S100A4 protein as well as the matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) are associated with diseases such as arthritis and cancer. This mini review focuses on in vitro and in vivo studies indicating S100A4 involvement in regulation of MMPs and TIMPs, and the biological and pathobiological consequences of this regulation.

Proteome analysis of hepatocellular carcinoma cell lines with different metastasis potentials by two-dimensional liquid chromatography

AIM: To analyze the proteome of hepatocellular carcinoma cell lines, MHCC97-H (high metastasis) and MHCC97-L (low metastasis), with different metastasis potentials by two-dimentional liquid phase chromatographic fractionation followed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS).

METHODS: Cell lysates of MHCC97-H and MHCC97-L were fractionated according to PI using chromatofocusing with analytical columns in the first dimension, followed by separation of the proteins in each PI fraction using nonporous reversed-phase high performance liquid chromatography (HPLC). A two-dimensional map of the protein content for each cell line based upon pI versus hydrophobicity as detected by UV absorption was generated and a differential display map indicating the presence of up- or down-regulated proteins was exhibited using ProteoVue and DltaVue software. The different proteins were digested by trypsin and MALDI-TOF/MS was performed.

RESULTS: Image analysis of two-dimensional map revealed 72 differentially expressed proteins between MHCC97-H and MHCC97-L cells, and 9 protein peaks (including M2 pyruvate kinase, α-subunit of ATP synthase, heat shock protein 60, Toll-like receptor 9, flavoprotein oxygenase, pro-calreticulin, manganese superoxide dismutase, nm23-H1, and G-protein-coupled receptor kinase 5) were further identified by tryptic digestion, peptide mass fingerprinting and mass spectrometry. Four proteins were up-regulated while 5 were down-regulated in MHCC97-H cells.

CONCLUSION: The identified differentially expressed proteins may play important roles in the metastasis of hepatocellular carcinoma.

Altered protein expression at early-stage rat hepatic neoplasia

Protein expression patterns were analyzed in a rat model of hepatic neoplasia to detect changes reflecting biological mechanism or potential therapeutic targets. The rat resistant hepatocyte model of carcinogenesis was studied, with a focus on the earliest preneoplastic lesion visible in the liver, the preneoplastic hyperplastic nodule. Expression differences were shown by two-dimensional polyacrylamide gel electrophoresis and image analysis. Polypeptide masses were measured by peptide mass fingerprinting using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF) and their sequences were obtained by tandem mass spectrometry. Alterations in expression of cytoskeletal and functional proteins were demonstrated, consistent with biological changes known to occur in the preneoplastic cells. Of particular interest was the differential expression of a serine protease inhibitor (serpin) with a role implicated in angiogenesis. Serpin, implicated in the inhibition of angiogenesis, is present in normal liver but has greatly reduced expression at the preneoplastic stage of liver cancer development. Immunofluorescence microscopy with antibodies to this serpin, kallistatin, supports the proteomic identification. Immunofluorescence microscopy with antibodies to the blood vessel marker von Willebrand factor provides evidence for neovascularization in the liver containing multiple preneoplastic nodules. These observations suggest that at an early stage of liver carcinogenesis reduction or loss of angiogenesis inhibitors may contribute to initiation of neoangiogenesis. A number of other identified proteins known to be associated with hepatomas are also present at early-stage neoplasia.

Toward the discovery of new biomarkers of hepatocellular carcinoma by proteomics

Primary liver cancer is the fifth most frequent neoplasm and the third most common cause of cancer-related death, with more than 500,000 new cases diagnosed yearly. The outcome for hepatocellular carcinoma (HCC) patients still remains dismal, partly because of our limited knowledge of its molecular pathogenesis and the difficulty in detecting the disease at its early stages. Therefore, studies aimed at the definition of the mechanisms associated with HCC progression and the identification of new biomarkers leading to early diagnosis and more effective therapeutic interventions are urgently needed. Proteomics is a rapidly expanding discipline that is expected to change the way in which diseases will be diagnosed, treated, and monitored in the near future. In the last few years, HCC has been extensively investigated using different proteomic approaches on HCC cell lines, animal models, and human tumor tissues. In this review, state-of-the-art technology on proteomics is overviewed, and recent advances in liver cancer proteomics and their clinical projections are discussed.