Overexpression of osteopontin is associated with intrahepatic metastasis, early recurrence, and poorer prognosis of surgically resected hepatocellular carcinoma

Osteopontin: regulation in tumor metastasis

Osteopontin is a secreted phosphoprotein that has been implicated as an important mediator of tumor metastasis and has been investigated for use as a biomarker for advanced disease and as a potential therapeutic target in the regulation of cancer metastasis. The OPN DNA sequence is highly conserved and the protein contains several important functional domains including alpha(v)beta integrin and CD44 binding sites. High levels of OPN expression correlate with tumor invasion, progression or metastasis in multiple cancer. Studies demonstrate that osteopontin mediates the molecular mechanisms which determine metastatic spread, such as prevention of apoptosis, extracellular matrix proteolysis and remodeling, cell migration, evasion of host-immune cells and neovascularization. Transcriptional regulation of OPN is complex and involves multiple pathways, including AP-1, Myc, v-Src, Runx/CBF, TGF-B/BMPs/Smad/Hox, and Wnt/ss-catenin/APC/GSK-3ss/Tcf-4. The current state of knowledge of OPN biology suggests that it is an attractive target for therapeutic modulation of metastatic disease.

Molecular mapping of human hepatocellular carcinoma provides deeper biological insight from genomic data

DNA microarray analysis of human cancer has resulted in considerable accumulation of global gene profiles. However, extraction and understanding the underlying biology of cancer progression remains a significant challenge. This study applied a novel integrative computational and analytical approach to this challenge in human hepatocellular carcinoma (HCC) with the aim of identifying potential molecular markers or novel therapeutic targets. We analysed 100 HCC tissue samples by human 30K DNA microarray. The gene expression data were uploaded into the network analysis tool, and the biological networks were displayed graphically. We identified several activated 'hotspot' regions harbouring a concentration of upregulated genes. Several 'hotspot' regions revealed integrin and Akt/NF-kappaB signalling. We identified key members linked to these signalling pathways including osteopontin (SPP1), glypican-3 (GPC3), annexin 2 (ANXA2), S100A10 and vimentin (VIM). Our integrative approach should significantly enhance the power of microarray data in identifying novel potential targets in human cancer.

Small integrin-binding ligand N-linked glycoproteins (SIBLINGs): multifunctional proteins in cancer

Numerous components and pathways are involved in the complex interplay between cancer cells and their environment. The family of glycophosphoproteins comprising osteopontin, bone sialoprotein, dentin matrix protein 1, dentin sialophosphoprotein and matrix extracellular phosphoglycoprotein - small integrin-binding ligand N-linked glycoproteins (SIBLINGs) - are emerging as important players in many stages of cancer progression. From their detection in various human cancers to the demonstration of their key functional roles during malignant transformation, invasion and metastasis, the SIBLINGs are proteins with potential as diagnostic and prognostic tools, as well as new therapeutic targets.

Overexpression of KIAA0101 predicts high stage, early tumor recurrence, and poor prognosis of hepatocellular carcinoma

PURPOSE

KIAA0101 is a proliferating cell nuclear antigen-associated factor and involved in cell proliferation. This study is to elucidate its role in the progression, early tumor recurrence (ETR), and prognosis of hepatocellular carcinoma (HCC).

EXPERIMENTAL DESIGN

KIAA0101 mRNA was measured by reverse transcription-PCR in 216 resected, unifocal, primary HCCs and its protein in 164 cases by immunohistochemistry.

RESULTS

KIAA0101 mRNA was overexpressed in 131 (61%) HCCs, and protein was detected in 105 (64%). KIAA0101 mRNA overexpression correlated with higher tumor grade (P = 0.0001), higher tumor stage with vascular invasion and various extents of intrahepatic spread (P = 1 x 10(-8)), ETR (P = 1.8 x 10(-6)), and lower 5-year survival (P = 0.0026). Multivariate analysis confirmed that KIAA0101 overexpression was an independent risk factor associated with high-grade tumor (P = 0.0001), high-stage tumor (P < 0.0001), and ETR (P = 0.0052) and thus contributed to poor prognosis. KIAA0101 protein-positive tumor cells accumulated at the borders of tumor macro-trabeculae and were more abundant in tumor thrombi than in the main tumors. Hence, KIAA0101 may contribute to growth advantage and resistance to hypoxic insult. In this series, p53 mutation was detected in 93 of 184 (51%) HCCs. In both p53-mutated and non-p53-mutated HCCs, KIAA0101 overexpression correlated with higher vascular invasion (stages IIIA to IV; all Ps < 0.0001) and, accordingly, led to lower 5-year survival rates (P = 0.011 and 0.029, respectively).

CONCLUSION

KIAA0101 correlates with enhanced metastatic potential and is a significant prognostic factor of HCC.

Osteopontin expression in normal skin and non-melanoma skin tumors

Osteopontin (OPN) is an adhesive, matricellular glycoprotein, whose expression is elevated in many types of cancer and has been shown to facilitate tumorigenesis in vivo. To understand the role of OPN in human skin cancer, this study is designed to determine whether OPN is expressed in premalignant [solar/actinic keratosis (AK)] and in malignant skin lesions such as squamous cell carcinomas (SCC) and basal cell carcinomas (BCC), as well as in normal skin exposed or not exposed to sunlight. Immunohistochemical analyses showed that OPN is expressed in SCC (20/20 cases) and in AK (16/16 cases), which are precursors to SCC, but is absent or minimally expressed in solid BCC (17 cases). However, positive staining for OPN was observed in those BCC that manifest differentiation toward epidermal appendages such as keratotic BCC. In sunlight-exposed normal skin, OPN is minimally expressed in the basal cell layer, but in contrast to those not exposed to sunlight, OPN is more prominent in the spinous cell layer with increasing intensity toward the granular cell layer. Additionally, OPN is expressed in the hair follicles, sebaceous glands, and sweat glands of normal skin. In conclusion, these data suggest that OPN is associated with keratinocyte differentiation and that it is expressed in AK and SCC, which have metastatic potential, but minimally expressed in solid BCC.

Prognostic significance of osteopontin expression in human gastric carcinoma

BACKGROUND

Osteopontin (OPN) is a secreted, integrin-binding glycophosphoprotein that has been implicated in the progression of various solid tumors. To evaluate the clinical significance of OPN in gastric carcinoma, we investigated OPN expression in resected tumors.

METHODS

Expression of OPN protein by gastric cancer cells was evaluated using western blot analysis. OPN messenger RNA (mRNA) expression in 18 gastric cancers was compared with that in the corresponding normal gastric epithelium by semiquantitative reverse transcription polymerase chain reaction (RT-PCR). Paraffin sections of tumors from 295 patients with gastric cancer were also investigated using immunohistochemistry.

RESULTS

All four gastric cancer cell lines analyzed using western blotting had almost the same level of OPN protein expression as the positive control (HeLa cells). OPN mRNA was upregulated in 83% (15/18) of the tumors studied. On immunohistochemical staining, 90 tumors were classified as negative (-), whereas 205 were classified as positive (1+, 2+, or 3+). The level of OPN protein expression was significantly associated with the patient's age (p = 0.04), tumor depth (p = 0.03), histological grade (p = 0.008), and hematogenous metastasis (p = 0.007). Kaplan-Meier analysis showed that OPN positivity was significantly associated with a shorter survival time (p = 0.027). Furthermore, multivariate analysis revealed that OPN positivity was an independent risk factor for hematogenous metastasis (p = 0.034).

CONCLUSIONS

The present findings suggest that increased tumor expression of OPN is an important determinant of shorter survival time and that OPN positivity may be useful for predicting the risk of hematogenous metastasis in gastric cancer patients.

Pathophysiological role of osteopontin in hepatic inflammation, toxicity, and cancer

Osteopontin (OPN) is a highly modified integrin-binding extracellular matrix glycophosphoprotein produced by cells of the immune system, epithelial tissue, smooth muscle cells, osteoblasts, and tumor cells. Extensive research has elucidated the pivotal role of OPN in cell signaling that controls inflammation, tumor progression, and metastasis. OPN interaction with the integrin receptors expressed on inflammatory cells through its arginine-glycine-aspartate (RGD) and non-RGD motifs promote migration and adhesion of cells. In the liver, it has been reported that hepatic Kupffer cells secrete OPN facilitating macrophage infiltration into necrotic areas following carbon tetrachloride liver toxicity. Recent work has highlighted the role of OPN in inflammatory liver diseases such as alcoholic and nonalcoholic liver disease and T-cell-mediated hepatitis. The role of OPN in hepatocellular carcinoma (HCC) has also generated significant interest, especially with regards to its role as a prognostic factor. OPN therefore appears to play an important role during liver inflammation and cancer. In this review we will present data to demonstrate the key role played by OPN in mediating hepatic inflammation (neutrophils, monocytes/macrophages, and lymphocytes) and its role in HCC. Greater understanding of the pathophysiologic role of OPN in hepatic inflammation and cancer may enable development of novel inflammation and cancer treatment strategies.

The potential role of intrinsic hypoxia markers as prognostic variables in cancer

Tumor hypoxia is related to tumor progression and therapy resistance, which leads to poor patient outcome. It has been suggested that measuring the hypoxic status of a tumor helps to predict patient outcome and to select more targeted treatment. However, current methods using needle electrodes or exogenous markers have limitations due to their invasiveness or necessity for preinjection. Recent studies showed that hypoxia-regulated genes could be alternatively used as endogenous hypoxia markers. This is a review of 15 hypoxia-regulated genes, including hypoxia-inducible factor-1 and its targets, and their correlation with tumor hypoxia and patient outcome from 213 studies. Though most of the studies showed significance of these genes in predicting prognosis, there was no definitive prognostic and hypoxia marker. In conclusion, this review suggests the need for further studies with standardized methods to examine gene expression, as well as the use of multiple gene expressions.

Human macrophages promote the motility and invasiveness of osteopontin-knockdown tumor cells

Increasing evidence indicates that macrophages in tumor stroma can significantly modify the malignant phenotypes of tumors. Osteopontin (OPN) is frequently overexpressed in cancers with high metastatic capacity and, thus, has been considered as a potential therapeutic target. To find out whether macrophages can affect the outcome of OPN-knockdown tumor cells, we used RNA interference (RNAi) to stably silence the OPN expression in the highly invasive human hepatoma cell line SK-Hep-1. Silencing of OPN markedly decreased the motility and invasiveness of the SK-Hep-1 cells. Further studies using this cell model revealed that coculture with human macrophages or macrophage-conditioned medium largely restored the migration and invasion potential of OPN-knockdown tumor cells. Moreover, such macrophage-promoted motility can be effectively blocked either by the addition of OPN-neutralizing antibody to the cocultured medium or by silencing OPN expression in macrophages. These results indicate that macrophage-derived OPN can compensate for the decrease of OPN and thereby restore the metastatic potential of OPN-knockdown tumor cells. Further characterization of the underlying mechanisms disclosed that macrophage-derived OPN exerted its function independently of the actin cytoskeleton rearrangement or the activation of matrix metalloproteinase and Rho families. Our results suggest that there are fine-tuned complex interactions between cancer cells and stroma cells, which may modify the outcome of cancer therapy, and therefore should be considered for the rational design of anticancer strategy.

An osteopontin fragment is essential for tumor cell invasion in hepatocellular carcinoma

Tumor cell invasion is a primary event in the metastatic progression of hepatocellular carcinoma (HCC). Our recent results indicate a concordant elevated expression of osteopontin (OPN) and matrix metalloproteinase-9 (MMP-9) in primary metastatic HCC. This study hypothesizes an MMP-9-directed cleavage of OPN that biologically contributes to HCC metastasis. We found that MMP-9 cleaved OPN into specific fragments in vitro, of which three could be identified by Edman degradation amino-acid sequencing. One of these fragments (OPN-5 kDa, residues 167-210) induced low-metastatic HCC cellular invasion via CD44 receptors, which was effectively blocked by the addition of small peptides within the region of OPN-5 kDa. Increased expression of an OPN splice variant (OPN-c) was associated with clinical metastatic HCC. Overexpression of OPN-c with physiological levels of MMP-9 enhanced cellular invasion and coincided with elevated OPN-5 kDa levels. Our data suggest that an alternative splicing event (OPN-c) promotes extracellular cleavage of OPN by MMP-9, thus releasing a distinct region of OPN (OPN-5 kDa) that is essential for HCC cellular invasion and appears to correlate with metastatic potential. The findings of this study may help to improve advanced-stage HCC prognosis and suggest the utility of small peptides for novel therapies.

Osteopontin promotes integrin activation through outside-in and inside-out mechanisms: OPN-CD44V interaction enhances survival in gastrointestinal cancer cells

Osteopontin (OPN) and splice variants of CD44 (CD44(V)) have independently been identified as markers for tumor progression. In this study, we show that both OPN and CD44(V) are frequently overexpressed in human gastric cancer and that OPN-engaged CD44(V) ligation confers cells an increased survival mediated through integrin activation. First, we show that OPN treatment confers cells an increased resistance to UV-induced apoptosis. The OPN-mediated antiapoptosis is dependent on the expression of the variant exon 6 (V6)- or V7-containing CD44 as shown by overexpression of individual CD44(V) in gastric AZ521 cells that express no or very low level of endogenous CD44 and by knockdown of the constitutively expressed V6-containing CD44 isoforms in colon HT29 cells. Although OPN also interacts with RGD integrins, OPN-RGD sequence is dispensable for OPN-mediated antiapoptosis. OPN-induced antiapoptosis is mainly attributed to the engagement of CD44(V) isoforms and the relay of an inside-out signaling via Src activity, leading to robust integrin activation. Furthermore, OPN-elicited antiapoptosis was observed when cells were plated on fibronectin but not on poly-D-lysin, and preincubation of cells with anti-integrin beta(1) antibody to block integrin-extracellular matrix (ECM) interaction or ectopic expression of the dominant-negative forms of focal adhesion kinase to block ECM-derived signal abolished OPN-induced survival, suggesting that OPN-elicited antiapoptotic function is propagated from matrix transduced by integrin. Taken together, we showed that OPN-CD44(V) interaction promotes ECM-derived survival signal mediated through integrin activation, which may play an important role in the pathogenic development and progression of gastric cancer.

Prognostic significance of osteopontin in hepatitis B virus-related hepatocellular carcinoma

BACKGROUND AND AIMS

Osteopontin (OPN) is known to be associated with metastasis in many types of cancers. Since OPN is a highly phosphorylated and glycosylated protein, the modification after transcription is very important to its function. In hepatocellular carcinoma (HCC), the elevated expression of OPN at mRNA levels and its relationship with metastasis and poorer prognosis of the patients have been reported. However, the prognostic impact of OPN at protein levels on the patients with hepatitis B virus (HBV)-related HCC after hepatectomy is still limited.

PATIENTS AND METHODS

The expression of OPN was examined at protein level by using immunohistochemistry in 72 patients who underwent hepatectomy for HBV-related HCC, and its prognostic significance in disease-free and overall survival of the patients was also analyzed by log-rank test and multivariate Cox regression analyses.

RESULTS

Thirty-nine of 72 (54.17%) HBV-related HCC specimens were positive for OPN with cytoplasmic staining. OPN was highly expressed in the specimens with capsular infiltration compared to those without (P<0.05), and also was significantly related with portal vein invasion (P<0.01) and lymph node invasion (P<0.01). The mean disease-free survival (DFS) was only 13.55+/-14.77 months when the HBV-related HCC specimens highly expressed OPN compared to 36.00+/-18.68 months for those with low expression (P<0.001). The overall survival (OS) of the patients was 18.63+/-17.28 months when the HCC over-expressed OPN compared to 42.59+/-16.85 months for HCC with the low expressed OPN (P<0.001). Multivariate analysis showed that OPN over-expression was the strongest independent adverse prognostic factor for both DFS (P=0.01) and OS (P=0.014).

CONCLUSIONS

OPN over-expression was closely related to capsular infiltration, venous invasion, lymph node metastasis, and also with worse prognosis, suggesting that OPN might be deemed as a useful molecular marker for predicting the prognosis of HCC.

Overexpression of tumour-associated trypsin inhibitor (TATI) enhances tumour growth and is associated with portal vein invasion, early recurrence and a stage-independent prognostic factor of hepatocellular carcinoma

Tumour-associated trypsin inhibitor (TATI) overexpresses in various tumours, but its clinicopathological significance in hepatocellular carcinoma (HCC) is unclear. Differential display analysis revealed expression of TATI in HCC. By RT-PCR in the linear range, TATI was found to be overexpressed in 176 of 258 unifocal primary HCCs (68%). TATI overexpression correlated with high-stage HCC (stage IIIB to IV) with portal vein (PV) invasion (p=0.00014), early tumour recurrence (ETR; p=0.00002), and a lower 5-year survival (p=0.000001), in both low- and high-stage HCC (p=0.033 and p=0.00036, respectively). Ectopic expression of TATI led to enhanced anchorage-independent tumour cell growth in vitro. To determine its potential as a part of a group of combined diagnostic markers, we analysed 235 HCCs for three genes encoding secretory proteins known to be overexpressed in HCC; these were TATI, AFP and osteopontin; 202 of the tumours (86%) overexpressed one or more of these genes. Further, HCC with a greater number of gene overexpressions produced bigger tumours (p=0.0024), had a higher rate of PV invasion (p= 1x10(-8)), had a higher ETR (p=1x10(-8)), and showed a lower 5-year survival (p=0.000001). We conclude that TATI overexpression contributes to cell growth advantage, enhances the metastatic potential of tumours and leads to advanced HCC with PV invasion. Thus, it is a stage-independent prognostic factor for HCC and a useful predictor for ETR. Moreover, it should be possible to use TATI, AFP and osteopontin as combined markers for molecular staging, the detection of HCC and for the prediction of ETR.

Osteopontin in metastatic lesions as a prognostic marker in ovarian cancers

Osteopontin (OPN) is expressed in various human cancers and associated with tumor progression, invasion and metastasis in many manners. The purpose of this study is to investigate the clinical significance of OPN expression in metastatic lesions of ovarian cancers, since the prognosis of the patients with peritoneal dissemination is extremely poor. In primary tumors and peritoneal metastatic lesions from 40 patients with stage III ovarian cancers, the protein levels of OPN and histoscores were determined by enzyme immunoassay and immunohistochemistry, respectively. Immunohistochemical staining revealed OPN was distributed in the cytoplasm and nuclear compartments of the cancer and stromal cells within and around the tumor. The OPN level was significantly (p < 0.05) increased in 32 of 40 metastatic lesions of ovarian cancers. The OPN increased cases identified by immunohistochemical staining were consistent with those identified by the sandwich immunoassay. The prognosis of the 32 patients with significant increase of OPN in ovarian cancers was extremely poor, whereas the 36-month survival rate of the 8 patients with no increase of OPN was 75%. Multivariate analysis revealed that the levels of OPN were independent predictors of prognosis from clinical characteristics (age, lesion size, histological types). OPN might be associated with peritoneal metastasis and its advancement, and that the OPN level in metastatic lesion may be a prognostic indicator in ovarian cancers.

L2dtl Is Essential for Cell Survival and Nuclear Division in Early Mouse Embryonic Development

l(2)dtl (lethal (2) denticleless), is an embryonic lethal homozygous mutation initially identified in Drosophila melanogaster that produces embryos that lack ventral denticle belts. In addition to nucleotide sequence, bioinformatic analysis has revealed a conservation of critical functional motifs among the human L2DTL, mouse L2dtl, and Drosophila l(2)dtl proteins. The function of the L2DTL protein in the development of mammalian embryos was studied using targeted disruption of the L2dtl gene in mice. The knock-out resulted in early embryonic lethality. L2dtl-/- embryos were deformed and terminated development at the 4-8-cell stage. Microinjection of a small interfering RNA (siRNA) vector (siRNA-L2dtl) into the two-cell stage nuclei of wild-type mouse embryos led to cell cycle progression failure, termination of cell division, and, eventually, embryonic death during the preimplantation stage. Morphological studies of the embryos 54 h after injection showed fragmentation of mitotic chromosomes and chromosomal lagging, hallmarks of mitotic catastrophe. The siRNA-L2dtl-treated embryos eventually lysed and failed to develop into blastocysts after 72 h of in vitro culturing. However, the embryos developed normally after they were microinjected into one nucleus of the two-celled embryos. The siRNA studies in HeLa cells showed that L2dtl protein depletion results in multinucleation and down-regulation of phosphatidylinositol 3-kinase, proliferating cell nuclear antigen, and PTTG1/securin, which might partially explain the mitotic catastrophe observed in L2dtl-depleted mouse embryos. Based on these findings, we conclude that L2dtl gene expression is essential for very early mouse embryonic development.

Plasma osteopontin is an independent prognostic marker for head and neck cancers

PURPOSE

To confirm the relationship between plasma osteopontin (OPN) levels and treatment outcomes in head and neck squamous cell carcinoma (HNSCC) patients in an expanded study.

PATIENTS AND METHODS

One hundred forty patients with newly diagnosed HNSCC were enrolled onto this study, 54 previously reported and 86 new patients. Pretreatment plasma OPN levels were assessed in all patients by an enzyme-linked immunosorbent assay method. OPN levels were correlated to treatment outcomes in the new group of patients. Detailed analyses were also performed on the relationship between OPN and tumor control rate, event-free survival (EFS), and postrelapse survival for the entire group.

RESULTS

Using a previously defined cut off point of 450 ng/mL, there was a significant correlation between OPN and freedom-from-relapse (P = .047), overall survival (P = .019), and EFS (P = .023) in the new, independent patient cohort (n = 86). Sequence of event analyses using the entire group (N = 140) revealed that OPN was an independent prognostic factor for initial tumor control, EFS in those who have achieved tumor control, and postrelapse survival.

CONCLUSION

In this expanded study, we were able to replicate the prognostic significance of OPN using a predefined cut off point in an independent patient group and demonstrated that plasma OPN is an independent prognostic marker for HNSCC.

The hepatic transcriptome in human liver disease

The transcriptome is the mRNA transcript pool in a cell, organ or tissue with the liver transcriptome being amongst the most complex of any organ. Functional genomics methodologies are now being widely utilized to study transcriptomes including the hepatic transcriptome. This review outlines commonly used methods of transcriptome analysis, especially gene array analysis, focusing on publications utilizing these methods to understand human liver disease. Additionally, we have outlined the relationship between transcript and protein expressions as well as summarizing what is known about the variability of the transcriptome in non-diseased liver tissue. The approaches covered include gene array analysis, serial analysis of gene expression, subtractive hybridization and differential display. The discussion focuses on primate whole organ studies and in-vitro cell culture systems utilized. It is now clear that there are a vast number research opportunities for transcriptome analysis of human liver disease as we attempt to better understand both non-diseased and disease hepatic mRNA expression. We conclude that hepatic transcriptome analysis has already made significant contributions to the understanding of human liver pathobiology.

Stathmin overexpression cooperates with p53 mutation and osteopontin overexpression, and is associated with tumour progression, early recurrence, and poor prognosis in hepatocellular carcinoma

Stathmin, a major microtubule-depolymerizing protein, is involved in cell cycle progression and cell motility. This study aimed to elucidate its role in the progression, early tumour recurrence (ETR), and prognosis of hepatocellular carcinoma (HCC). Stathmin mRNA was overexpressed in 88/156 (56%) resected, unifocal, primary HCCs, while p53 mutation was present in 72 (46%) and osteopontin mRNA overexpression in 79 (51%). Stathmin mRNA expression exhibited high concordance (93%) with protein expression in 107 cases examined by immunohistochemistry. Stathmin overexpression correlated with high alpha-fetoprotein (>200 ng/ml, p = 0.02), larger tumour size (>5 cm, p = 0.012), high tumour grade (p < 0.0002), high tumour stage (stage IIIA-IV) with vascular invasion and various degrees of intrahepatic metastasis (p < 1 x 10(-8)), ETR (p = 0.003), and lower 5-year survival (p = 0.0007). Stathmin protein expression was often more intense in the peripheral regions of tumour trabeculae, tumour borders, and portal vein tumour thrombi. Stathmin overexpression correlated with p53 mutation (p = 0.017) and osteopontin overexpression (p = 1 x 10(-8)), both of which were associated with vascular invasion (both p < 0.0001) and poorer prognosis (p < 0.0004 and p = 0.0004, respectively). Regardless of the status of p53 mutation or osteopontin expression, stathmin overexpression was associated with higher vascular invasion (all p < 0.0001). Approximately 90% of HCCs harbouring stathmin overexpression with concomitant p53 mutation or osteopontin overexpression exhibited vascular invasion, and hence the lowest 5-year survival, p = 0.00018 and p = 0.0009, respectively. However, we did not find that stathmin overexpression exerted prognostic impact independent of tumour stage. In conclusion, stathmin expression correlates with metastatic potential, is an important prognostic factor for HCC, and may serve as a useful marker to predict ETR.

Effects of THBS3, SPARC and SPP1 expression on biological behavior and survival in patients with osteosarcoma

BACKGROUND

Osteosarcoma is a very aggressive tumor with a propensity to metastasize and invade surrounding tissue. Identification of the molecular determinants of invasion and metastatic potential may guide the development of a rational strategy for devising specific therapies that target the pathways leading to osteosarcoma.

METHODS

In this study, we used pathway-focused low density expression cDNA arrays to screen for candidate genes related to tumor progression. Expression patterns of the selected genes were validated by real time PCR on osteosarcoma patient tumor samples and correlated with clinical and pathological data.

RESULTS

THBS3, SPARC and SPP1 were identified as genes differentially expressed in osteosarcoma. In particular, THBS3 was expressed at significantly high levels (p = 0.0001) in biopsies from patients with metastasis at diagnosis, which is a predictor of worse overall survival, event-free survival and relapse free survival at diagnosis. After chemotherapy, patients with tumors over-expressing THBS3 have worse relapse free survival. High SPARC expression was found in 51/55 (96.3%) osteosarcoma samples derived from 43 patients, and correlated with the worst event-free survival (p = 0.03) and relapse free survival (p = 0.07). Overexpression of SPP1 was found in 47 of 53 (89%) osteosarcomas correlating with better overall survival, event-free survival and relapse free survival at diagnosis.

CONCLUSION

In this study three genes were identified with pattern of differential gene expression associated with a phenotypic role in metastasis and invasion. Interestingly all encode for proteins involved in extracellular remodeling suggesting potential roles in osteosarcoma progression. This is the first report on the THBS3 gene working as a stimulator of tumor progression. Higher levels of THBS3 maintain the capacity of angiogenesis. High levels of SPARC are not required for tumor progression but are necessary for tumor growth and maintenance. SPP1 is not necessary for tumor progression in osteosarcoma and may be associated with inflammatory response and bone remodeling, functioning as a good biomarker.

Elevated plasma osteopontin levels in patients with hepatocellular carcinoma

OBJECTIVES

Osteopontin (OPN) is a secreted glycoprotein, frequently associated with various tumors. We investigated the usefulness of plasma OPN level as a biomarker for hepatocellular carcinoma (HCC).

METHODS

We determined plasma levels of OPN, alpha-fetoprotein (AFP), and prothrombin induced by vitamin K absence II (PIVKA II) in a group of 62 HCC patients, in 60 patients with chronic liver diseases, and in 60 healthy control individuals using a standardized ELISA kit. To determine the source of elevated plasma level of OPN, immunohistochemical analysis of 285 HCC samples on tissue microarray was performed.

RESULTS

Plasma OPN levels in the HCC patients (median 954 ng/mL, range 168-5,742) were significantly higher (p-value < 0.001) than those patients with chronic liver diseases (381 ng/mL, 29-1,688) or of a healthy control group (155 ng/mL, 10-766). Within the HCC patient group, plasma OPN level increased significantly with advancing degree of Child-Pugh class and of tumor stage. Diagnostic sensitivity and specificity of OPN for HCC was 87% and 82%, respectively (cut-off value: 617.6 ng/mL). OPN had a greater area under curve value (0.898) than AFP (0.745) or PIVKA II (0.578), suggesting superior diagnostic accuracy of OPN. Immunohistochemistry of 285 samples of HCC showed that OPN was expressed in 92 of 285 tumors (32.3%). OPN expression was found in the malignant hepatocytes and cancer-infiltrating macrophages, not in the noncancerous hepatocytes or Kupffer cells.

CONCLUSIONS

These data propose elevated plasma OPN levels as a potential biomarker for HCC.

Role of the integrin-binding protein osteopontin in lymphatic metastasis of breast cancer

Although a primary route of breast cancer metastasis is believed to be via lymphatics, the molecular factors involved are poorly understood. We hypothesized that one such factor may be the integrin-binding protein osteopontin (OPN), and we investigated this clinically and experimentally. In breast cancer patients undergoing sentinel lymph node biopsy, OPN levels were significantly higher in lymph node metastases than in the primary tumor (P < 0.001). To test the functional contribution of OPN to lymphatic metastasis and to determine whether the RGD (Arg-Gly-Asp) integrin-binding sequence of OPN is important for this process, we transfected wild-type OPN or mutant OPN (lacking the RGD sequence) into MDA-MB-468 human breast cancer cells. In vitro, cells overexpressing OPN demonstrated increased anchorage-independent growth in soft agar (P = 0.001) and increased RGD-dependent adhesion (P = 0.045). Following mammary fat pad injection of nude mice, cells overexpressing OPN showed increased lymphovascular invasion, lymph node metastases, and lung micrometastases at earlier time points (P = 0.024). Loss of the RGD region partially abrogated this effect in the lymphatics (P = 0.038). These novel findings indicate that OPN is a key molecular player involved in lymphatic metastasis of breast cancer, potentially by affecting RGD-mediated adhesive interactions and by enhancing the establishment/persistence of tumor cells in the lymphatics.

Liver transplantation and recurrent hepatocellular carcinoma: predictive value of nodule size in a retrospective and explant study

BACKGROUND

Recurrence of hepatocellular carcinoma (HCC) after liver transplantation (LT) remains a major cause of post-LT death.

METHODS

To assess which preoperative and postoperative variables were related to recurrence of HCC after LT in patients with cirrhosis and HCC, we evaluated 96 patients with cirrhosis (74 with known HCC and 22 with incidental HCC) who survived more than 1 month after LT.

RESULTS

The median waiting list time was 36 days (range 1-370 days), and the median interval from detection to transplant was 180 days (range 14-1460 days). The size of largest nodule on imaging was strongly associated with recurrence (odds ratio 1.03; 95% confidence interval 0.99-1.06; P=0.064) when transplantation was performed for known HCC. Among postoperative variables, only the largest nodule diameter (independently of the number of smaller nodules) was multivariately associated with recurrence (odds ratio 1.05; 95% confidence interval 1.01-1.08; P=0.005). The best predictive cutoff was 35 mm in diameter, based on a receiver operating curve with 1-, 3-, and 5-year recurrence-free survival of 90%, 73%, and 49%, respectively, for patients with a nodule 35 mm in diameter or more compared with 96%, 93%, and 89% (P=0.0005), respectively, for patients with smaller nodules.

CONCLUSIONS

In our cohort with a short waiting list time, only the largest nodule diameter, especially in the explant, predicted recurrence after LT independently of the number of nodules. New proposals for increasing the diameter of the largest nodule as a selection criteria for LT do not agree with our data, which on the contrary indicate the optimal nodule diameter should be 35 mm or less.

The prognostic significance of preoperative plasma levels of osteopontin in patients with hepatocellular carcinoma

We aimed to evaluate the prognostic value of preoperative plasma osteopontin (OPN) levels in 101 patients with hepatocellular carcinoma (HCC) who underwent liver resection. Plasma OPN levels were detected by ELISA. The association of plasma OPN levels of patients with clinicopathological characteristics, tumor recurrence, and survival was analyzed. The median plasma OPN level of patients was 176.90 ng/ml (range 13.73-780.00 ng/ml), which was significantly higher than that of 24 healthy volunteers (63.74 ng/ml, range 12.20-122.32 ng/ml). Plasma OPN levels were significantly different in patients with different numbers of tumor nodules (168.18 and 217.11 ng/ml for single and multiple nodules, respectively; P = 0.002), different Edmondson's grades (201.24, 168.36, and 503.58 ng/ml for grades I, II, and III/IV, respectively; P = 0.015), and different TNM stages (168.16, 167.54, and 216.18 ng/ml for stages I, II, and III/IV, respectively; P = 0.016). Significantly higher plasma OPN levels were found in patients with a recurrence of HCC after resection, compared with those without recurrence (213.55 versus 153.70 ng/ml; P = 0.0013). A higher plasma OPN level was a leading independent prognostic factor for both overall survival (OS) and disease-free survival (DFS) in univariate and multivariate Cox models. This suggests that the preoperative plasma OPN level can be used as a predictive marker for HCC recurrence and may be helpful to assess the prognosis of patients with HCC after surgery.

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Clinical implications of osteopontin in metastatic lesions of uterine cervical cancers

Osteopontin (OPN) is a glycophosphoprotein that has variety of physiological functions. OPN is expressed in various human cancers and associated with tumor progression, invasion and metastasis in many manners. The purpose of this study is to investigate the clinical significance of OPN expression in metastatic lymph node of uterine cervical cancers, since the prognosis of the patients with lymph node metastasis is extremely poor. Immunohistochemical staining revealed OPN was distributed in the cytoplasm and nuclear compartments of the cancer and stromal cells within and around the tumor. In 25 of the 40 cases, stronger staining for OPN was found in the cancer cells or stromal cells of the metastatic lymph node lesion than in those of the primary tumor. The OPN level was significantly (P<0.05) increased in 25 of 40 metastatic lymph node lesions of uterine cervical cancers. The OPN increased cases identified by immunohistochemical staining were consistent with those identified by the sandwich immunoassay. The prognosis of the 25 patients with significant increase of OPN in uterine cervical cancers was extremely poor, whereas the 24-month survival rate of the 15 patients with no increase of OPN was 67%. This indicates that OPN may contribute to lymph node metastasis and its advancement, and that the OPN level in metastatic lesion may be a prognostic indicator in uterine cervical cancers.

Ets-1 and runx2 regulate transcription of a metastatic gene, osteopontin, in murine colorectal cancer cells

Osteopontin (OPN) is a sialic acid-rich phosphoprotein secreted by a wide variety of cancers. We have shown previously that OPN is necessary for mediating hepatic metastasis in CT26 colorectal cancer cells. Although a variety of stimuli can induce OPN, the molecular mechanisms that regulate OPN gene transcription in colorectal cancer are unknown. We hypothesized that cis- and trans-regulatory elements determine OPN transcription in CT26 cells. OPN transcription was analyzed in CT26 cancer cells and compared with YAMC (young adult mouse colon) epithelial cells. Clonal deletion analysis of OPN promoter-luciferase constructs identified cis-regulatory regions. A specific promoter region, nucleotide (nt) -107 to -174, demonstrated a >8.0-fold increase in luciferase activity in CT26 compared with YAMC. Gel-shift assays sublocalized two cis-regulatory regions, nt -101 to -123 and nt -121 to -145, which specifically bind CT26 nuclear proteins. Competition with unlabeled mutant oligonucleotides revealed that the regions nt -115 to -118 and nt -129 to -134 were essential for protein binding. Subsequent supershift and chromatin immunoprecipitation assays confirmed the corresponding nuclear proteins to be Ets-1 and Runx2. Functional relevance was demonstrated through mutations in the Ets-1 and Runx2 consensus binding sites resulting in >60% decrease in OPN transcription. Ets-1 and Runx2 protein expression in CT26 was ablated using antisense oligonucleotides and resulted in a >7-fold decrease in OPN protein expression. Ets-1 and Runx2 are critical transcriptional regulators of OPN expression in CT26 colorectal cancer cells. Suppression of these transcription factors results in significant down-regulation of the OPN metastasis protein.

Loss of E-cadherin mRNA and gain of osteopontin mRNA are useful markers for detecting early recurrence of HCV-related hepatocellular carcinoma

BACKGROUND AND OBJECTIVES

We investigated whether expression of E-cadherin (E-cad) and osteopontin (OPN) mRNAs could predict the early recurrence of HCV-associated hepatocellular carcinoma (HCV-HCC) after curative surgery.

METHODS

Forty-four HCV-HCC patients who underwent curative hepatectomy were divided into three categories: category 1--recurrence (3 mR+: n = 6) or non-recurrence (3 mR-: n = 38) within 3 months; category 2--recurrence (6 mR+: n = 4) or non-recurrence (6 mR-: n = 34) between 3-6 months; category 3--recurrence (1 yR+: n = 4) or non-recurrence (1 yR-: n = 30) between 6-12 months. Levels of expression of E-cad and OPN mRNAs were analyzed quantitatively by real-time PCR and calculated using the formula: t = (copy of E-cad or OPN/copy of GAPDH) x 1,000.

RESULTS

The t-value for E-cad was significantly lower in 3 mR+ than in 3 mR- (0.4 and 28.1, P < 0.05), in 6 mR+ than in 6 mR- (4.0 and 30.6, P < 0.05), and in 1 yR+ than in 1 yR- (9.2 and 32.9, respectively, P < 0.05). The t-value for OPN was higher in 3 mR+ than in 3 mR- (92.6 and 65.7, P = 0.57), in 6 mR+ than in 6 mR- (457.1 and 58.15, respectively, P = 0.24), and in 1 yR+ than in 1 yR- (221.8 and 53.5, respectively, P = 0.06).

CONCLUSIONS

Low expression of E-cad mRNA and high expression of OPN mRNA are associated with a higher likelihood of early recurrence of HCV-HCC.

Osteopontin expression correlates with prognostic variables and survival in clear cell renal cell carcinoma

BACKGROUND AND OBJECTIVES

Osteopontin (OPN) is a phosphorylated glycoprotein with diverse functions including tumorigenesis and tumor cell metastasis. Recently, it has been detected in a growing number of human tumors, and assessed as a potential prognostic marker. The aim of this study was to analyze the expression of OPN in normal renal tissue and clear cell renal cell carcinomas (CRCCs), and to assess its prognostic significance.

METHODS

The expression of OPN protein was immunohistochemically analyzed in 171 CRCCs and compared to usual clinicopathological parameters such as tumor size, nuclear grade, pathological stage, Ki-67 proliferation index, and cancer-specific survival.

RESULTS

In normal renal parenchyma, the expression of OPN was seen in distal tubular epithelial cells, calcifications, and some stromal cells. The upregulation of OPN was observed in 61 CRCCs (35.7%) in the form of cytoplasmic granular staining of various intensities. Statistical analysis showed correlation of the OPN expression with tumor size (P < 0.001), Fuhrman nuclear grade (P < 0.001), pathological stage (P = 0.011), and Ki-67 proliferation index (P < 0.001). Moreover, patients with OPN-positive tumors had significantly worse prognosis in comparison to patients with tumors lacking OPN protein (P = 0.004).

CONCLUSION

Our results suggest that overexpression of OPN is involved in the progression of CRCC.

Nitric oxide-dependent osteopontin expression induces metastatic behavior in HepG2 cells

Our objective was to delineate the role of nitric oxide (NO) in osteopontin (OPN)-associated metastatic properties in HepG2 cells. OPN is the major phosphoprotein secreted by malignant cells in patients with advanced metastatic cancer, is frequently overexpressed in human tumors, and has been implicated as a key mediator of tumor cell metastasis. OPN is significantly overexpressed in hepatocellular cancer (HCC) and correlates with capsular infiltration and behavior. In addition, significantly increased inducible nitric oxide synthase (iNOS) and NO expression are found in HCC. In archived human samples of normal, cirrhotic, and HCC livers, we demonstrate that iNOS and OPN protein are strongly coexpressed in hepatoma cells. In the setting of cirrhosis, hepatocytes express iNOS, but not OPN. Further in vitro studies performed with HepG2 hepatocellular cancer cells demonstrate that exogenous NO transcriptionally upregulates OPN expression. Enhanced expression of OPN in this setting is associated with increased in vitro cell adhesion and invasion. These data suggest that NO enhances HCC expression of OPN and, as a result, conveys a metastatic phenotype.

Microarray data analysis of mouse neoplasia

Microarray gene expression analysis offers great promise to help us understand the molecular events of experimental carcinogenesis, but have such promises been fulfilled? Studies of gene expression profiles of rodent are being published and demonstrate that yes, indeed, gene array data is furthering our understanding of tumor biology. Recent studies have identified differentially expressed genes in rodent mammary, colon, lung, and liver tumors. Although relatively few genes on the rodent arrays have been fully characterized, information has been generated to better identify signatures of histologic type and grade, understand invasion and metastasis, identify candidate biomarkers of early development, identify gene networks in carcinogenesis, understand responses to therapy, and decifer overlap with molecular events in human cancers. Data from mouse lung, mammary gland, and liver tumor studies are reviewed as examples of how to approach and interpret gene array data. Methods of gene array data analysis were also applied for discovery of genes involved in the regression of mouse liver tumors induced by chlordane, a nongenotoxic murine hepatocarcinogen. Promises are beginning to be fulfilled and it is clear that pathologists and toxicologists, in collaboration with molecular biologists, bioinformatists,and other scientists are making great strides in the design, analysis, and interpretation of microarray data for cancer studies.

Osteopontin expression correlates with melanoma invasion

Melanoma is one of the most aggressive cancers affecting humans. Although early melanomas are curable with surgical excision, metastatic melanomas are associated with high mortality. The mechanism of melanoma development, progression, and metastasis is largely unknown. In order to uncover genes unique to melanoma cells, we used high-density DNA microarrays to examine the gene expression profiles of metastatic melanoma nodules using benign nevi as controls. Over 190 genes were significantly overexpressed in metastatic melanomas compared with normal nevi by at least 2-fold. One of the most abundantly expressed genes in metastatic melanoma nodules is osteopontin (OPN). Immunohistochemistry staining on tissue microarrays and individual skin biopsies representing different stages of melanoma progression revealed that OPN expression is first acquired at the step of melanoma tissue invasion. In addition, blocking of OPN expression by RNA interference reduced melanoma cell numbers in vitro. Our observations suggest that OPN may be acquired early in melanoma development and progression, and may enhance tumor cell growth in invasive melanoma.

Expression of osteopontin correlates with portal biliary proliferation and fibrosis in biliary atresia

The acquired or perinatal form of biliary atresia is a Th1 fibro-inflammatory disease affecting both the extrahepatic and intrahepatic bile ducts. Osteopontin (OPN) is a Th1 cytokine implicated in several fibro-inflammatory and autoimmune diseases. We examined the expression of OPN in acquired biliary atresia in comparison to normal liver and several pediatric cholestatic liver diseases. We also assessed OPN expression by cultured human bile duct epithelial cells. We found that liver OPN mRNA and protein expression were significantly increased in biliary atresia versus normal and other cholestatic diseases. OPN expression in biliary atresia was localized to epithelium of proliferating biliary structures (ductules and/or ducts) and bile plugs contained therein. No portal biliary OPN expression could be demonstrated in normal liver, syndromic biliary atresia, biliary obstruction not due to biliary atresia, and idiopathic neonatal hepatitis. OPN expression by human bile duct epithelial cells in culture was responsive to IL-2 and TNF-alpha. Our results demonstrate an up-regulation of OPN expression by interlobular biliary epithelium in biliary atresia, which correlates with biliary proliferation and portal fibrosis. These findings suggest a role for OPN in the pathogenesis of biliary atresia.

Optimization of liver biopsy RNA sampling and use of reference RNA for cDNA microarray analysis

In this study, we used the rat liver as a model system to optimize the conditions for extracting RNA from liver biopsies for use in cDNA microarrays. We found that a 5-mm biopsy with a 16-gauge needle and storage in RNA later at 4 degrees C were optimal conditions for RNA extraction. The most important factor for the quantity and quality of RNA extraction was the sample diameter. Using the optimized sampling conditions and a cDNA microarray, we compared the expression of genes in the normal and the fibrotic tissues of the LEC rat liver, a model of liver tumorigenesis, with SD rat liver RNA as a reference. We found 29 genes that were up-regulated and 33 genes that were down-regulated in the fibrotic part of the liver. Furthermore, with the help of the reference RNA, we were able to classify the expression profiles into five groups without complex mathematical analyses; without the reference RNA, the genes could be classified into only two groups. Finally, we found that osteopontin was expressed at a very high level in the fibrotic portion of the LEC rat liver. This cDNA microarray result was validated by immunohistochemistry, which showed an elevated expression of osteopontin in the region of cholangiocarcinoma and a lack of expression in normal tissues. With optimized conditions, we should be able to apply the microarray system for routine practice.

Molecular profiling of hepatocellular carcinomas by cDNA microarray

Hepatocellular carcinoma (HCC) is one of the most common cancers in the world. Conventional diagnosis and treatment of this malignancy have been dismal and should be complemented by novel tools. The development and progress of HCC are believed to be caused by the accumulation of genetic changes resulting in altered expression of thousands of cancer-related genes, which can be measured by globe genetic analysis. Gene expression profiling of HCC has been employed to elucidate hepatocarcinogenesis and disclose molecular mechanisms underlying complex clinical features. Identifying phenotype-associated genes/profiles has impacts on current diagnosis and management strategy of HCC. In spite of some pitfalls of this technology and challenges in improving the research process, scrutinous validation of profiling data of HCC combined with other approaches will eventually benefit the patients.

Expression of osteopontin and CD44 molecule in papillary renal cell tumors

The aim of the study was to analyze the expression of CD44 adhesion molecule and its ligand osteopontin in papillary renal cell tumors, and to assess the possible prognostic significance of CD44 and osteopontin expression in papillary renal cell carcinomas. The expression of the standard and v6 exon containing isoforms of CD44 molecule, as well as of its ligand osteopontin, was immunohistochemically evaluated in 43 papillary renal cell tumors, which included 5 adenomas and 38 carcinomas. In order to assess their prognostic significance, the results obtained in papillary renal cell carcinomas were compared to usual clinicopathological parameters such as tumor size, histological grade, pathological stage, and Ki-67 proliferation index. Normal renal tissue was negative for CD44s and v6 isoforms, while the expression of osteopontin was found in distal tubular epithelial cells in the form of cytoplasmic granular positivity. CD44s and v6 isoforms were upregulated in 22 (58%) and 12 (32%) out of 38 carcinomas, respectively. Among all clinicopathological parameters examined, we only found significant association of CD44s-positive carcinomas with lower pathological stage (p=0.026). Papillary renal cell adenomas were generally negative for CD44s, except for focal positivity found in one sample. The osteopontin protein was detected in all adenomas and all papillary renal cell carcinomas, except one. Our results show constitutive expression of osteopontin in papillary renal tumors, including papillary renal cell adenomas. The upregulation of CD44s and v6 isoforms, although found in a considerable number of papillary renal cell carcinomas, does not appear to have any prognostic value in this type of renal cancer.

Osteopontin regulates multiple functions contributing to human colon cancer development and progression

Osteopontin (OPN) is a secreted phosphoglycoprotein known to interact with a number of integrin receptors. While increased OPN expression has been reported in a number of human cancers, and its cognate receptors (alphav-beta3, alphav-beta5, and alphav-beta1 integrins and CD44) have been identified, its role in colon cancer development and progression has not been extensively studied. We previously identified, using a combination of gene expression and tissue microarrays, that increased OPN expression is concordant with tumor stage. The current study examined the functional role of OPN in colon cancer progression and metastatic potential. The principal findings of this study were that both endogenous OPN expression (via stable transfection) as well as exogenous OPN (added to culture medium) enhanced the motility and invasive capacity of human colon cancer cells in vitro. OPN appeared to regulate motility though interaction with CD44. OPN expression also reduced intercellular (homotypic) adhesion, an important characteristic of metastatic cancer cells. Stable transfection of four poorly tumorigenic human colon cancer cell lines with OPN also resulted in enhanced tumorigenicity in vivo with increased proliferation and increased CD31 positive microvessel counts, concordant with the degree of OPN expression. Collectively, these results suggest that OPN may affect multiple functional components contributing to human colon cancer progression and solidifies its role in this process.

The role of Osteopontin in tumor metastasis

Osteopontin (OPN) is a glyco-phosphoprotein that is expressed and secreted by numerous human cancers. OPN functions in cell adhesion, chemotaxis, macrophage-directed interleukin-10 (IL-10) suppression, stress-dependent angiogenesis, prevention of apoptosis, and anchorage-independent growth of tumor cells by regulating cell-matrix interactions and cellular signaling through binding with integrin and CD44 receptors. While constitutive expression of OPN exists in several cell types, induced expression has been detected in T-lymphocytes, epidermal cells, bone cells, macrophages, and tumor cells in remodeling processes such as inflammation, ischemia-reperfusion, bone resorption, and tumor progression. Recently, substantial evidence has linked OPN with the regulation of metastatic spread by tumor cells. However, the molecular mechanisms that define the role of OPN in tumor metastasis are incompletely understood. Transcriptional regulators that contribute to the induction of OPN expression have received significant attention as potential modulators of the OPN-mediated metastatic phenotype. The following review will discuss the molecular structure of OPN, the evidence for its functional role in tumor cell metastasis, the downstream signals that activate invasive mechanisms, and the recent reports concerning regulation of OPN transcription.

A transcriptional repressor of osteopontin expression in the 4T1 murine breast cancer cell line

Osteopontin (OPN) is a highly hydrophilic and negatively charged sialoprotein of approximately 298 amino acids which is an important mediator of tumor metastatic behavior. We have previously demonstrated that endotoxin-dependent OPN gene transcription is regulated by a constitutive transcriptional repressor protein, heterogeneous nuclear ribonucleoprotein A/B (hnRNP-A/B). However, in the context of cancer, the role of hnRNP-A/B in the transcriptional regulation of OPN and its metastasis-promoting functions has not been previously studied. We examined hnRNP-A/B in the 4T1 murine mammary epithelial tumor cell line, a thioguanine resistant subline which closely mimics stage IV breast cancer in humans. Our data indicate that hnRNP-A/B p37 binds to the OPN promoter, significantly decreases OPN promoter activity and mRNA levels, ablates OPN protein expression, and inhibits OPN dependent in vitro correlates of metastatic behavior, motility, and invasion. These results are unique and may suggest new therapies to re-establish loco-regional control of cancers.

Recent progress in predictive biomarkers for metastatic recurrence of human hepatocellular carcinoma: a review of the literature

Molecular markers (biomarkers) for hepatocellular carcinoma (HCC) metastasis and recurrence could provide additional information to that gained from traditional histopathological features. A large number of biomarkers have been shown to have potential predictive significance. One important aspect of this is to detect the transcripts of tumor-associated antigens (such as AFP, MAGEs, and CK19), which are proposed as predictive markers of HCC cells disseminated into the circulation and for metastatic recurrence. Another important aspect is to analyze the molecular markers for cellular malignancy phenotype, including DNA ploidy, cellular proliferation index, cell cycle regulators, oncogenes, and tumor suppressors (especially p53 gene), as well as telomerase activity. Molecular factors involved in the process of HCC invasion and metastasis, including adhesion molecules (E-cadherin, catenins, ICAM-1, laminin-5, CD44 variants, osteopontin), proteinases responsible for the degradation of extracellular matrix (MMPs, uPA system), as well as angiogenesis regulators (such as VEGF, intratumor MVD), have also been shown to be potential predictors for HCC metastatic recurrence and clinical outcomes. One important new trend is to widely delineate biomarkers with genomic and proteomic expression with reference to predicting metastatic recurrence, molecular diagnosis, and classification, which has been drawing more attention recently. Body fluid (particularly blood and urine) testing for biomarkers is easily accessible and more useful in clinical patients. The prognostic significance of circulating DNA in plasma or serum and its genetic alterations is another important direction. More attention should be paid to these areas in the future. As understanding of tumor biology deepens, more and more new biomarkers with high sensitivity and specificity for HCC metastatic recurrence could be found and routinely used in clinical assays. However, the combination of the pathological features and some of the biomarkers mentioned above seems to be more practical up to now.

Role of osteopontin in tumour progression

Since its first identification as a transformation-associated protein, osteopontin (OPN) has been recognised as important in the processes of tumorigenicity and metastasis. Here, we review the evidence that OPN might be considered as a candidate prognostic marker in human cancer. In animal systems, evidence from cell injection experiments and genetically manipulated mice suggest an important but complex role for the protein in tumour progression. Moreover, studies in a variety of human cancers associate high levels of OPN expression in tumours or in blood with more advanced cancers. The mechanism of action of OPN in promoting cancer is still unclear, and we consider aspects of OPN biology that can complicate interpretation of human studies. Nevertheless, growing evidence supports a role for OPN as a potential prognostic factor for various human cancers.

A decade's studies on metastasis of hepatocellular carcinoma

Metastasis remains one of the major challenges before hepatocellular carcinoma (HCC) is finally conquered. This paper summarized a decade's studies on HCC metastasis at the Liver Cancer Institute of Fudan University. We have established a stepwise metastatic human HCC model system, which included a metastatic HCC model in nude mice (LCI-D20), a HCC cell line with high metastatic potential (MHCC97), a relatively low metastatic potential cell clone (MHCC97L) and several stepwise high metastatic potential cell clones (MHCC97H, HCCLM3, and HCCLM6) from their parent MHCC97 cell. Endeavors have been made for searching human HCC metastasis-related chromosomes/proteins/genes. Monogene-based studies revealed that HCC invasion/metastasis was similar to that of other solid tumors, and the biological characteristics of small HCC were only slightly better than that of large HCC. Using comparative genomic hybridization (CGH), fluorescence in situ hybridization (FISH), genotyping, cDNA microarray, and 2-dimensional gel electrophoresis, we obtained some interesting results. In particular, in collaboration with the National Institute of Health (NIH) in the United States, we generated a molecular signature that can classify metastatic HCC patients, identified osteopontin as a lead gene in the signature, and found that genes favoring metastasis progression were initiated in the primary tumors. We also found that chromosome 8p deletion, particularly in the region of 8p23, was associated with HCC metastasis. Cytokeratin 19 was identified as one of the proteins, which was found in MHCC97H, but not in MHCC97L cells. Experimental interventions using the high metastatic nude mice model have provided clues for the prevention of HCC metastasis. Translation from workbench to bedside demonstrated that serum VEGF, microvessel density, and p53 scoring may be of value for the prediction of postoperative metastatic recurrence. Interferon alpha proved effective for the prevention of recurrence both experimentally and clinically. In conclusion, HCC metastasis that probably initiated in the primary tumor is a multigene-involved, multistep, and changing process. The further elucidation of the mechanism underlying HCC metastasis will provide a more solid basis for the prediction and prevention of the metastatic recurrence of HCC.