Constitutively nuclear FOXO3a localization predicts poor survival and promotes Akt phosphorylation in breast cancer.

BACKGROUND: The PI3K-Akt signal pathway plays a key role in tumorigenesis and the development of drug-resistance. Cytotoxic chemotherapy resistance is linked to limited therapeutic options and poor prognosis. METHODOLOGY/PRINCIPAL FINDINGS: Examination of FOXO3a and phosphorylated-Akt (P-Akt) expression in breast cancer tissue microarrays showed nuclear FOXO3a was associated with lymph node positivity (p = 0.052), poor prognosis (p = 0.014), and P-Akt expression in invasive ductal carcinoma. Using tamoxifen and doxorubicin-sensitive and -resistant breast cancer cell lines as models, we found that doxorubicin- but not tamoxifen-resistance is associated with nuclear accumulation of FOXO3a, consistent with the finding that sustained nuclear FOXO3a is associated with poor prognosis. We also established that doxorubicin treatment induces proliferation arrest and FOXO3a nuclear relocation in sensitive breast cancer cells. Induction of FOXO3a activity in doxorubicin-sensitive MCF-7 cells was sufficient to promote Akt phosphorylation and arrest cell proliferation. Conversely, knockdown of endogenous FOXO3a expression reduced PI3K/Akt activity. Using MDA-MB-231 cells, in which FOXO3a activity can be induced by 4-hydroxytamoxifen, we showed that FOXO3a induction up-regulates PI3K-Akt activity and enhanced doxorubicin resistance. However FOXO3a induction has little effect on cell proliferation, indicating that FOXO3a or its downstream activity is deregulated in the cytotoxic drug resistant breast cancer cells. Thus, our results suggest that sustained FOXO3a activation can enhance hyperactivation of the PI3K/Akt pathway. CONCLUSIONS/SIGNIFICANCE: Together these data suggest that lymph node metastasis and poor survival in invasive ductal breast carcinoma are linked to an uncoupling of the Akt-FOXO3a signaling axis. In these breast cancers activated Akt fails to inactivate and re-localize FOXO3a to the cytoplasm, and nuclear-targeted FOXO3a does not induce cell death or cell cycle arrest. As such, sustained nuclear FOXO3a expression in breast cancer may culminate in cancer progression and the development of an aggressive phenotype similar to that observed in cytotoxic chemotherapy resistant breast cancer cell models.

Granulin-epithelin precursor as a therapeutic target for hepatocellular carcinoma.

UNLABELLED: Primary liver cancer, hepatocellular carcinoma (HCC), is the fifth most common cancer and the third leading cancer killer in the world. There is no effective therapeutic option for most HCC patients. A new therapeutic strategy is essential. Granulin-epithelin precursor (GEP, also called progranulin, acrogranin, or PC-derived growth factor) was identified as a potential therapeutic target for HCC from our earlier genome-wide expression profiles. We aimed to conduct a detailed investigation with in vitro and animal experiments. We developed the anti-GEP monoclonal antibody (mAb), and examined its effect on hepatoma cells and normal liver cells in vitro. A nude mice model transplanted with human HCC was used to investigate if anti-GEP mAb can inhibit tumor growth in vivo. We demonstrated that anti-GEP mAb inhibited the growth of hepatoma cells but revealed no significant effect on normal liver cells. In the nude mice model transplanted with human HCC, anti-GEP mAb decreased the serum GEP level and inhibited the growth of established tumors in a dose-dependent manner. The anti-GEP mAb reduced tumor cell proliferation via the p44/42 MAPK and Akt pathways, and reduced tumor angiogenesis to deprive the nutrient supply with reduced microvessel density and tumor vascular endothelial growth factor level. CONCLUSION: We have shown that anti-GEP antibody can inhibit HCC growth, providing evidence that GEP is a therapeutic target for HCC treatment.

Inhibition of hepatocellular carcinoma invasion by suppression of claudin-10 in HLE cells.

Previously, we showed that down-regulation of claudin-10 (CLDN-10) in hepatocellular carcinoma is associated with prolonged disease-free survival after curative surgery. Claudins are important tight junction components. Increasing evidence shows that claudins are involved in cancer progression but each member of claudins is specifically expressed in a variety of malignancies. The biological role of CLDN-10 in hepatocellular carcinoma is unexplored. In the current study, we investigated the CLDN-10 function in two different hepatocellular carcinoma cell lines by in vitro assays with the CLDN-10 overexpression and small interfering RNA-mediated knockdown transfectants. We observed that overexpression of CLDN-10 conferred malignant phenotypes to hepatocellular carcinoma cells, Hep3B, which lack CLDN-10 expression, by promoting cancer cell survival, motility, and invasiveness. More importantly, matrix metalloproteinase 2 (MMP2) was up-regulated. Increase in mRNA transcription and protein expression of membrane type 1-MMP (MT1-MMP) was also observed in the CLDN-10 transfectants, where MT1-MMP was a protease shown to promote intrahepatic metastasis in hepatocellular carcinoma in our earlier study. In addition, CLDN-1, CLDN-2, and CLDN-4 was up-regulated in CLDN-10 overexpression transfectants, indicating that the expression of CLDN-10 in cancer cells might affect the expression levels of its family members. On the contrary, small interfering RNA-based knockdown of CLDN-10 in HLE, an invasive cell line with high level of CLDN-10 expression, abolished invasion and strongly decreased activation of MMPs and claudin members expression. These findings showed that CLDN-10 is functionally involved in hepatocellular carcinoma invasion and is a potential target for hepatocellular carcinoma therapy.

Atypical localization of membrane type 1-matrix metalloproteinase in the nucleus is associated with aggressive features of hepatocellular carcinoma.

Membrane type 1-matrix metalloproteinase (MT1-MMP) is a versatile proteinase and recent studies indicated it could be internalized. Our earlier study found that it is overexpressed in hepatocellular carcinoma (HCC) and could promote intrahepatic metastasis. The present study was conducted to examine its subcellular localization and its clinicopathological significance in HCC after curative partial hepatectomy. Localization of MT1-MMP in 101 pairs of HCCs and their adjacent liver tissues, and 8 normal liver tissues was examined by the immunohistochemical method. MT1-MMP protein was localized at membrane and cytoplasm of hepatocytes in the normal and tumor adjacent liver tissues. In contrast, the HCCs were highly heterogeneous with variable degrees of membrane, cytoplasmic, and even nuclear staining. Interestingly, patients with presence of nuclear MT1-MMP were associated with poor overall survival (log-rank test, P=0.043) and large tumor size (>5 cm) (Fisher's exact test, P=0.031). Subcellular distribution was further demonstrated by Western blotting and immunofluorescence with Hep3B stable transfectant overexpressing MT1-MMP. Western blot analyses of subcellular fractions confirmed a differential partitioning of various post-translationally modified MT1-MMP in these fractions. Different antibodies corroborated the presence of MT1-MMP in the nuclear fraction. Concomitant nuclear presence of MMP2 with MT1-MMP further indicated its potential involvement in the nuclear functions. MT1-MMP co-localized with caveolin-1 at the perinuclear region, suggesting nuclear translocation of MT1-MMP via caveolae-mediated endocytosis. In summary, the association of nuclear MT1-MMP with aggressive tumor features including poor prognosis and large tumor expands its functional repertoire and further indicates a new functional role of MMPs within nuclei of tumor cells.

Preoperative plasma transcript AA454543 level is an independent prognostic factor for hepatocellular carcinoma after partial hepatectomy.

BACKGROUND: We have previously reported that tissue expression levels of transcript AA454543 in hepatocellular carcinoma (HCC) are significantly higher than those of normal livers, livers with cirrhosis, and livers with hepatitis. In addition, a higher level of transcript AA454543 in tumor tissues is associated with poor prognosis. We aim to examine whether quantitative measurement of preoperative plasma transcript AA454543 can provide similar prognostic information. PATIENTS AND METHODS: Blood samples were obtained from 84 HCC patients before surgery. Real-time quantitative reverse transcription-polymerase chain reaction, using TaqMan system, was employed to measure plasma transcript AA454543 and alpha-fetoprotein (AFP) RNA levels. We assessed their prediction power in prognosis using univariate and multivariate analyses. RESULTS: High plasma transcript AA454543 RNA levels were associated with poor overall survival (log-rank test, P < .01). Patients with different plasma AFP RNA levels revealed no difference in overall survival (log-rank test, P = .88). By multivariate Cox regression analysis, plasma transcript AA454543 RNA level (hazard ratio = 4.8, P < .01) and tumor stage (hazard ratio = 1.7, P < .01) were determined to be independent risk factors for the prediction of overall survival. CONCLUSION: Preoperative plasma transcript AA454543 RNA level can provide prognostic information for HCC patients receiving curative partial hepatectomy.

Claudin-10 expression level is associated with recurrence of primary hepatocellular carcinoma.

PURPOSE: Hepatocellular carcinoma (HCC) patients with the same clinicopathologic features can have remarkably different disease outcomes after curative hepatectomy. To address this issue, we evaluated the cDNA microarray gene expression profiles of HCCs and identified claudin-10 expression level was associated with disease recurrence. The aim of the current study is to validate the microarray data by an alternative research method applicable for routine practice. EXPERIMENTAL DESIGN: Quantitative reverse transcription-PCR (RT-PCR) was used to validate the microarray data on claudin-10 expression level. The assay was repeated on a separate HCC sample set to consolidate the prognostic significance of claudin-10. RESULTS: Claudin-10 expression level by quantitative RT-PCR and by microarray measurement showed a high concordance (r = 0.602, P < 0.001). Quantitative RT-PCR was repeated on a separate HCC sample set and the association of claudin-10 expression with recurrence was again confirmed (hazard ratio, 1.2; 95% confidence interval, 1.0-1.4; P = 0.011). By multivariable Cox regression analysis, claudin-10 expression and pathologic tumor-node-metastasis stage were independent factors for prediction of disease recurrence. CONCLUSION: Claudin-10 expression of HCC can be used as a molecular marker for disease recurrence after curative hepatectomy.

Mechanism of metastasis by membrane type 1-matrix metalloproteinase in hepatocellular carcinoma.

AIM: To investigate the precise role of membrane type 1-matrix metalloproteinase (MT1-MMP) in hepatocellular carcinoma (HCC) metastasis. METHODS: Human HCC cells Hep3B with overexpression of MT1-MMP were established by stable transfection, and compared with control cells carrying the empty vector. Cells were examined in vivo for their differences in the metastatic ability of athymic nude mice, and analyzed in vitro for their differences in invasion ability by invasion chamber coated with Matrigel, adhesion towards collagen I and migration through culture chamber. Cell proliferation and apoptosis in adherent and suspension status were evaluated by MTT and flow cytometry analysis. RESULTS: We found that overexpression of MT1-MMP could increase intrahepatic metastasis in nude mice with orthotopic implantation of HCC cells (incidence of 100% [MT1-MMP transfectants] vs 40% [vector control transfectants], P<0.05). MT1-MMP could also enhance cell invasion through Matrigel (107.7 vs 39.3 cells/field, P<0.001), adhesion towards matrix (0.30 vs 0.12 absorbance unit at 540 nm, P<0.001), cell migration (89.3 vs 39.0 cells/field, P<0.001), and cell proliferation (24.3 vs 40.5 h/doubling, P<0.001). We also observed that MT1-MMP supported cell survival (71.4% vs 23.9%, P<0.001) with reduced apoptosis (43.7% vs 51.0%, P<0.05) in an attachment-free environment. CONCLUSION: MT1-MMP overexpression could enhance metastasis. In addition to its active role in matrix degradation during tumor invasion, MT1-MMP enhances tumor cell survival upon challenge of detachment, which is important during metastasis when cells enter the circulation.

Liver as an ideal target for gene therapy: expression of CTLA4Ig by retroviral gene transfer.

BACKGROUND AND AIMS: Liver has been a target organ for gene therapy as it plays a central role in metabolism and production of serum proteins. Many metabolic disorders result from a deficiency of liver-derived protein products. In transplantation settings, modulation of the immune responses caused by CTLA4Ig protein has been shown to be an attractive direction. In this study, we investigated the efficacy of hepatocyte transduction via introduction of the exogenous CTLA4Ig gene to the rat liver graft by retrovirus vector, and examined the presence of target serum protein after gene transfers. METHODS: We constructed a replication defective retroviral vector that contained the CTLA4Ig gene. The liver graft regeneration index was first examined by 5-bromo-2-deoxyuridine, Ki-67 and proliferating cell nuclear antigen antibodies to determine the optimal time of gene transduction. The liver graft was then perfused with the retroviral vector, and animals were killed at constant time points to examine for the presence of CTLA4 protein in the graft and peripheral blood. RESULTS: CTLA4 protein was detected on postoperative days 5, 9 and 14, with liver graft tissue transduction indexes of 7.2, 10.9 and 1.8, respectively. Blood protein levels were at 151.6, 26.5 and 21.4 rhog/mL, respectively. A transduction index reaching 22.1 was observed in the graft with the most rapid liver regeneration. CONCLUSIONS: We had established the gene delivery model in rat with auxiliary partial liver transplantation. Expression of the exogenous gene delivered by retrovirus was demonstrated in the liver with secretion of diffusible protein in the bloodstream. The present study provides important information for gene transfer using the liver to produce the target protein in situ and as serum protein. This will also be applicable to the treatment of other metabolic diseases.