Alpha-fetoprotein stimulated the expression of some oncogenes in human hepatocellular carcinoma Bel 7402 cells

Alpha-fetoprotein: Past, present, and future

Alpha-fetoprotein (AFP) is a glycoprotein that plays an important role in immune regulation with critical involvement in early human development and maintaining the immune balance during pregnancy. Postfetal development, the regulatory mechanisms controlling AFP undergo a shift and AFP gene transcription is suppressed. Instead, these enhancers refocus their activity to maintain albumin gene transcription throughout adulthood. During the postnatal period, AFP expression can increase in the setting of hepatocyte injury, regeneration, and malignant transformation. It is the first oncoprotein discovered and is routinely used as part of a screening strategy for HCC. AFP has been shown to be a powerful prognostic biomarker, and multiple HCC prognosis models confirmed the independent prognostic utility of AFP. AFP is also a useful predictive biomarker for monitoring the treatment response of HCC. In addition to its role as a biomarker, AFP plays important roles in immune modulation to promote tumorigenesis and thus has been investigated as a therapeutic target in HCC. In this review article, we aim to provide an overview of AFP, encompassing the discovery, biological role, and utility as an HCC biomarker in combination with other biomarkers and how it impacts clinical practice and future direction.

The role of alpha-fetoprotein in the tumor microenvironment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a prevalent malignant cancer worldwide, characterized by high morbidity and mortality rates. Alpha-fetoprotein (AFP) is a glycoprotein synthesized by the liver and yolk sac during fetal development. However, the serum levels of AFP exhibit a significant correlation with the onset and progression of HCC in adults. Extensive research has demonstrated that the tumor microenvironment (TME) plays a crucial role in the malignant transformation of HCC, and AFP is a key factor in the TME, promoting HCC development. The objective of this review was to analyze the existing knowledge regarding the role of AFP in the TME. Specifically, this review focused on the effect of AFP on various cells in the TME, tumor immune evasion, and clinical application of AFP in the diagnosis and treatment of HCC. These findings offer valuable insights into the clinical treatment of HCC.

Rationale for Tailoring an Alternative Oncology Trial Using a Novel Gallium-Based Nanocomplex: Mechanistic Insights and Preclinical Challenges

Introduction: In the fight against cancer, cisplatin is most widely used as a clinical mainstay for the chemotherapy of various human cancers. Meanwhile, its cytotoxic profile, as well as drug resistance, limits its widespread application. The goal of precision medicine is to tailor an optimized therapeutic program based on the biology of the disease. Recently, nanotechnology has been demonstrated to be promising in this scenario. Objective: The current work provides a rationale for the design of an alternative oncology trial for the treatment of hepatocarcinogenesis using a novel eco-friendly nanocomplex, namely gallic acid-coated gallium nanoparticles. Moreover, the study tests whether the antineoplastic efficacy of gallic acid-coated gallium nanoparticles could be enhanced or not when it is administrated together with cisplatin. Methods: The work comprised a series of both in vitro and in vivo investigations. The in vivo therapeutic efficacy of such treatments, against diethylnitrosamine-induced hepatocarcinogenesis, was strictly evaluated by tracking target genes expressions, iron homeostasis, diverse biomarkers alterations, and lastly, routine paraclinical investigations were also assessed. Results: The in vitro biological evaluation of gallic acid-coated gallium nanoparticles in a HepG-2 cancer cell line established its superior cytotoxicity. Else more, the results of the in vivo experiment highlighted that gallic acid-coated gallium nanoparticles could diminish key hallmarks of cancer by ameliorating most of the investigated parameters. This was well-appreciated with the histopathological findings of the liver architectures of the treated groups. Conclusions: Our findings suggest that novel biogenic Ga-based nanocomplexes may potentially present new hope for the development of alternative liver cancer therapeutics, which should attract further scientific interest.

The Emerging Influences of Alpha-Fetoprotein in the Tumorigenesis and Progression of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the sixth most common cancer worldwide, and its mortality rate is the third-highest, after lung cancer and colorectal cancer. Currently, systematic targeted therapies for HCC mainly include multiple kinase inhibitors and immunotherapy. However, these drugs carry a black-box warning about the potential for inducing severe toxicity, and they do not significantly prolong the survival period of patients due to the highly heterogeneous characteristics of HCC etiology. In order to improve the prediction, effective treatment and prognosis of HCC, the tools and different biomarkers in clinical practices are recommended. Alpha-fetoprotein (AFP) is the earliest and the most widely used serum marker in the detection of HCC. Interestingly, serum AFP and cytoplasmic AFP show different, even opposite, roles in the cancer progression of HCC. This review focuses on biological characteristics, regulatory mechanisms for gene expression, emerging influences of AFP in HCC and its possible implications in HCC-targeted therapy.

TCP10L negatively regulates alpha-fetoprotein expression in hepatocellular carcinoma

Alpha-fetoprotein (AFP) is one of the most commonly used and reliable biomarkers for Hepatocellular carcinoma（HCC). However, the underlying mechanism of AFP expression in HCC is poorly understood. In this study, we found that TCP10L, a gene specifically expressed in the liver, is down-regulated in HCC and that its expression inversely correlates with AFP expression. Moreover, overexpression of TCP10L suppresses AFP expression whereas knockdown of TCP10L increases AFP ex-pression, suggesting that TCP10L might be a negative regulator of AFP. We found that TCP10L is associated with the AFP promoter and inhibits AFP promoter-driven transcriptional acti-vity. Taken together, these results indicate that TCP10L nega-tively regulates AFP expression in HCC and that it could be a potential prognostic marker and therapeutic target for HCC.

Role of Alpha-Fetoprotein in Hepatocellular Carcinoma Drug Resistance

Hepatocellular carcinoma (HCC) is a major type of primary liver cancer and a major cause of cancer-related deaths worldwide because of its high recurrence rate and poor prognosis. Surgical resection is currently the major treatment measure for patients in the early and middle stages of the disease. Because due to late diagnosis, most patients already miss the opportunity for surgery upon disease confirmation, conservative chemotherapy (drug treatment) remains an important method of comprehensive treatment for patients with middle- and late-stage liver cancer. However, multidrug resistance (MDR) in patients with HCC severely reduces the treatment effect and is an important obstacle to chemotherapeutic success. Alpha-fetoprotein (AFP) is an important biomarker for the diagnosis of HCC. The serum expression levels of AFP in many patients with HCC are increased, and a persistently increased AFP level is a risk factor for HCC progression. Many studies have indicated that AFP functions as an immune suppressor, and AFP can promote malignant transformation during HCC development and might be involved in the process of MDR in patients with liver cancer. This review describes drug resistance mechanisms during HCC drug treatment and reviews the relationship between the mechanism of AFP in HCC development and progression and HCC drug resistance.

AFP-Inhibiting Fragments for Drug Delivery: The Promise and Challenges of Targeting Therapeutics to Cancers

Alpha fetoprotein (AFP) plays a key role in stimulating the growth, metastasis and drug resistance of hepatocellular carcinoma (HCC). AFP is an important target molecule in the treatment of HCC. The application of AFP-derived peptides, AFP fragments and recombinant AFP (AFP-inhibiting fragments, AIFs) to inhibit the binding of AFP to intracellular proteins or its receptors is the basis of a new strategy for the treatment of HCC and other cancers. In addition, AIFs can be combined with drugs and delivery agents to target treatments to cancer. AIFs conjugated to anticancer drugs not only destroy cancer cells with these drugs but also activate immune cells to kill cancer cells. Furthermore, AIF delivery of drugs relieves immunosuppression and enhances chemotherapy effects. The synergism of immunotherapy and targeted chemotherapy is expected to play an important role in enhancing the treatment effect of patients with cancer. AIF delivery of drugs will be an available strategy for the targeted treatment of cancer in the future.

Biomarkers in Hepatocellular Carcinoma: Current Status and Future Perspectives

Hepatocellular carcinoma (HCC) is the most common primary liver cancer and one of the leading causes of cancer-related death worldwide. HCC is highly heterogeneous, both within the tumor and among individuals, which is closely related to the HCC surveillance, diagnosis, prognosis, and treatment response. With the advances of next-generation sequencing, the genomic landscape of HCC has been identified which vastly improves our understanding of genetic and epigenetic changes and their interaction during HCC development. In particular, gene mutations, epigenetic modifications, aberrant expression of coding and non-coding RNAs have been extensively explored and many of them are considered as biomarkers for HCC. Most recently, the gut microbiome has been proposed as potential non-invasive biomarkers for HCC diagnosis. In this review, we summarize the current development of HCC biomarkers studies and provide insights on further steps towards precision medicine of HCC.

AFP promotes HCC progression by suppressing the HuR-mediated Fas/FADD apoptotic pathway

Hepatocellular carcinoma (HCC) is a major leading cause of cancer-related death worldwide. Alpha fetoprotein (AFP) is reactivated in a majority of hepatocellular carcinoma (HCC) and associated with poor patient outcomes. Although increasing evidence has shown that AFP can regulate HCC cell growth, the precise functions of AFP in hepatocarcinogenesis and the associated underlying mechanism remain incompletely understood. In this study, we demostrated that depleting AFP significantly suppressed diethylnitrosamine (DEN)-induced liver tumor progression in an AFP gene-deficient mouse model. Similarly, knocking down AFP expression inhibited human HCC cell proliferation and tumor growth by inducing apoptosis. AFP expression level was inversely associated with the apoptotic rate in mouse and human HCC specimens. Investigation of potential cross-talk between AFP and apoptotic signaling revealed that AFP exerted its growth-promoting effect by suppressing the Fas/FADD-mediated extrinsic apoptotic pathway. Mechanistically, AFP bound to the RNA-binding protein HuR, increasing the accumulation of HuR in the cytoplasm and subsequent inhibition of Fas mRNA translation. In addition, we found that inhibiting AFP enhanced the cytotoxicity of therapeutics to AFP-positive HCC cells by activating HuR-mediated Fas/FADD apoptotic signaling. Conclusion: Our study defined the pro-oncogenic role of AFP in HCC progression and uncovered a novel antiapoptotic mechanism connecting AFP to HuR-mediated Fas translation. Our findings suggest that AFP is involved in the pathogenesis and chemosensitivity of HCC and that blockade of AFP may be a promising strategy to treat advanced HCC.

Post-treatment alpha-fetoprotein response predicts prognosis of patients with hepatocellular carcinoma: A meta-analysis

BACKGROUND

Post-treatment alpha-fetoprotein (AFP) response has been reported to be associated with prognosis of hepatocellular carcinoma (HCC) patients, but the results were not consistent. This meta-analysis aimed to explore the relationship between AFP response and clinical outcomes of HCC.

METHODS

PubMed, Embase, Medline and Cochrane library were searched for relevant articles published before March 20, 2019. The data were analyzed using RevMan5.3 software.

RESULTS

Twenty-nine articles with 4726 HCC patients were finally included for analysis. The pooled results showed that post-treatment AFP response was significantly associated with overall survival (OS) (hazard ratio (HR) = 0.41, 95% confidence interval (CI): 0.35-0.47, P <.001), progression free survival (PFS) (HR = 0.46, 95% CI: 0.39-0.54, P <.001) and recurrence free survival (RFS) (HR = 0.41, 95% CI: 0.29-0.56, P <.001) of HCC patients.

CONCLUSION

post-treatment AFP response might be a useful prognostic marker for HCC patients.

More Than a Tumor Marker…A Potential Role for Alpha-Feto Protein in Inflammatory Bowel Disease

BACKGROUND

Human alpha-fetoprotein (hAFP) is a glycoprotein derived from the gut entoderm and expressed sequentially by cells of the yolk sac, fetal liver, and gastrointestinal tract. By adulthood, serum levels of alpha-fetoprotein (AFP) are undetectable in healthy, nonpregnant adults. Despite the clinical utilities of AFP monitoring in pregnancy and malignancy, much remains to be determined regarding its potential physiological functions.

METHODS

We focused on literature related to AFP's immunoregulatory role and its ability to modulate disease activity both in animal models of autoimmune disorders and in human clinical studies.

RESULTS

Evidence suggests that AFP plays an important role in immunoregulation by inducing T-cell suppressor activity, downregulating dendritic-like cell antigen expression, and impairing the function of macrophages. Studies evaluating AFP and its effects in rodent models of autoimmune diseases have shown that AFP is associated with downregulation of inflammation. Observations in studies of pregnant patients with immune-mediated inflammatory diseases have also described potential correlations between AFP expression and disease activity during different stages of pregnancy and postpartum.

CONCLUSIONS

We propose further prospective evaluations of AFP expression during pregnancy in inflammatory bowel disease patients to further correlate with disease activity and consider the potential of AFP as a novel therapeutic agent.

Drug-eluting bead transarterial chemoembolization is efficient and well-tolerated in treating elderly Chinese hepatocellular carcinoma patients

This study aimed to evaluate the efficacy and safety of drug-eluting bead transarterial chemoembolization (DEB-TACE), and to explore its prognostic factors in elderly Chinese hepatocellular carcinoma (HCC) patients. 93 elderly HCC patients undergoing DEB-TACE were prospectively enrolled. Treatment response was assessed by mRECIST criteriaat1 month post DEB-TACE treatment, and progression free survival (PFS) and overall survival (OS) were calculated. Liver function and adverse events (AEs) within 1 month post DEB-TACE were documented. Complete response (CR) rate and objective response rate (ORR) were 18.3% and 87.1%, respectively. Additionally, medians of PFS and OS were 9.0 months and 21.0 months, respectively. Multivariate logistic regression revealed that no factor independently predicted CR achievement, while tumor size ≥5.0 cm and AFP abnormal were independent factors for predicting both shorter PFS and OS, and higher BCLC stage was an independent predictive factor for unfavorable OS. As to safety profiles, the percentages of patients with abnormal TBIL, ALT, AST, and ALP were increased at 1 week, while they were not different at 1 month post DEB-TACE treatment compared with baseline. Most frequent AEs were pain, fever, nausea or vomiting; skin discolorations, myelosuppression, and other AEs were relatively rare. In conclusion, DEB-TACE was efficient and well tolerated in elderly HCC patients, and increased tumor size, abnormal AFP, as well as higher BCLC stage could be independent markers for predicting worse prognosis.

Alpha-Fetoprotein and Hepatocellular Carcinoma Immunity

Hepatocarcinoma is one of the most prevalent gastroenterological cancers in the world with less effective therapy. As an oncofetal antigen and diagnostic marker for liver cancer, alpha-fetoprotein (AFP) possesses a variety of biological functions. Except for its diagnosis in liver cancer, AFP has become a target for liver cancer immunotherapy. Although the immunogenicity of AFP is weak and it could induce the immune escapes through inhibiting the function of dendritic cells, natural killer cells, and T lymphocytes, AFP has attracted more attention in liver cancer immunotherapy. By in vitro modification, the immunogenicity and immune response of AFP could be enhanced. AFP-modified immune cell vaccine or peptide vaccine has displayed the specific antitumor immunity against AFP-positive tumor cells and laid a better foundation for the immunotherapy of liver cancer.

Binding characterization of the targeting drug AIMPILA to AFP receptors in human tumor xenografts

The main objective of this study was the characterization of preclinical tumor models based on their expression of alpha-fetoprotein receptor (RECAF) for targeting cancer cells with a new non-covalent complex (AIMPILA) containing alpha-fetoprotein as the carrier and Atractyloside as an apoptosis-inducing agent. For that purpose, we measured the amount of RECAF in the homogenates of the grafted tumors T47D and SW620 and in HepG2 cell extracts. We also determined the alpha-fetoprotein binding specificity of the targeting drug AIMPILA using a solid-phase chemiluminescent assay with AIMPILA-Acrdidinium. We found that RECAF is practically absent from healthy mice tissues (100 Units/mg) where in malignant cells, the amount of alpha-fetoprotein receptors follows this order: T47D (9152 Units/mg) > HepG2 (4865 Units/mg) > SW620 (2839 Units/mg). This agrees with our findings regarding AIMPILA-induced tumor growth inhibition (T47D (T/C = 22%) > HepG2 (T/C = 51%) > SW620 (T/C = 70%), where T/C is the ratio of tumor volume in treated vs control animals). Our results demonstrate that the therapeutic response to the targeting drug AIMPILA strongly depends on the RECAF expression by human tumors and confirms the choice of the tumor models used for an AIMPILA preclinical study.

Changes of alpha-fetoprotein levels could predict recurrent hepatocellular carcinoma survival after trans-arterial chemoembolization

Background

There is paucity of information concerning whether AFP change is a predictor of prognosis for recurrent hepatocellular carcinoma (RHCC) patients after trans-arterial chemoembolization (TACE).

Methods

A total of 177 RHCC patients who received TACE as first-line therapy were retrospectively analyzed. The patients were classified into three groups according to their pre-TACE and post-TACE AFP levels (group A: AFP decreased, group B: AFP consistent normal, and group C: AFP increased). The recurrence to death survival (RTDS) and overall survival (OS) were estimated by the Kaplan-Meier method, and compared by the log-rank test. Multivariate analyses were performed to identify prognostic factors for OS and RTDS.

Results

There was no significant difference among the three groups concerning the baseline characteristics. The median overall survival (OS) was 74.5 months in group A (95% confidence interval (CI): 63.5, 85.6), 64.0 months in group B (95% CI: 52.3, 75.7) and 29.0 months in group C (95% CI: 24.1, 33.9; P<0.001). The median recurrence to death survival (RTDS) was 66.5 months (95% CI: 53.4, 79.6) in group A, 50.4 months (95% CI: 39.5, 61.4) in group B and 17.7 months (95% CI: 13.4, 22.1; P<0.001) in group C. Multivariate analysis revealed that tumor size at resection stage, tumor number at recurrent stage, cycles of TACE, mRECIST response and AFP change after TACE were significant independent risk factors for RTDS and OS.

Conclusions

AFP change could predict the prognoses of patients with RHCC who received trans-arterial chemoembolization, which may help clinicians make subsequent treatment decision.

Expression of β-catenin protein in hepatocellular carcinoma and its relationship with alpha-fetoprotein

This study aimed to investigate the expression of β-catenin in hepatocellular carcinoma (HCC) tissues and its relationship with α-fetoprotein (AFP) in HCC. Immunohistochemistry was used to determine the expression of β-catenin in normal liver tissues (n=10), liver cirrhosis tissues (n=20), and primary HCC tissues (n=60). The relationship between β-catenin expression and clinical parameters of HCC was investigated. Real-time PCR and Western blotting were used to detect the mRNA and protein expression levels of β-catenin in the liver cancer cell line SMMC-7721 transfected with a plasmid encoding AFP, and also the mRNA and protein expression levels of β-catenin were measured in the liver cancer cell line Huh7 before and after the transfection with AFP shRNA plasmids. The results showed that β-catenin was only expressed on the cell membrane in normal liver tissues. Its localization to the cytoplasm and nucleus of cells was observed in a small proportion of cirrhotic tissues or adjacent HCC tissues, and such ectopic expression of β-catenin was predominant in HCC tissues. The abnormal expression of β-catenin was correlated with serum AFP levels, cancer cell differentiation and vascular invasion (P<0.05). Additionally, the increased expression of AFP resulted in the upregulation of β-catenin mRNA and protein levels, while knockdown of AFP with AFP shRNA led to significantly decreased β-catenin mRNA and protein levels (P<0.05). It was suggested that the abnormal expression of β-catenin is implicated in hepatic carcinogenesis and development. AFP can lead to increased expression of β-catenin, which may account for the poor prognosis of AFP-associated HCC patients.

Physiology of Alpha-Fetoprotein as a Biomarker for Perinatal Distress: Relevance to Adverse Pregnancy Outcome

The many physiologic roles of human alpha-fetoprotein (HAFP) and its correlation with perinatal distress/pregnancy outcome are rarely addressed together in the biomedical literature, even though HAFP has long been used as a biomarker for fetal birth defects. Although the well being of the fetus can be monitored by the measurement of gestational age–dependent HAFP in biologic fluid levels (serum, amniotic fluid, urine, and vaginal fluids) throughout pregnancy, the majority of clinical reports reflect largely second trimester and (less likely) first trimester testing due to regulatory clinical restrictions. However, reports of third-trimester and pregnancy term measurement of HAFP levels performed in clinical research and/or investigational settings have gradually increased over the years and have expanded our base knowledge of AFP-associated pregnancy disorders during these stages. The different structural forms of HAFP (isoforms, epitopes, molecular variants, etc.) detected in the various biologic fluid compartments have been limited by antibody recognition of specific epitopic sites developed by the kit manufacturers based on antibody specificity, sensitivity, and precision. Concomitantly, the advances in elucidating the various biologic actions of AFP are opening new vistas toward understanding the physiologic roles of AFP during pregnancy. The present review surveys HAFP as a biomarker for fetal distress during the perinatal period in view of its structural and functional properties. An attempt is then made to relate the AFP fluid levels to adverse pregnancy complications and outcomes. Hence, the present review was divided into two major sections: (I) AFP structure and function considerations and (II) the relationship of AFP levels to the distressed fetus during the third trimester and at term.

Paclitaxel induces apoptosis and reduces proliferation by targeting epidermal growth factor receptor signaling pathway in oral cavity squamous cell carcinoma

Oral cavity cancer is common worldwide. Furthermore, the epidermal growth factor receptor (EGFR) signaling pathway is considered to be constitutively activated in oral cancers. Paclitaxel is widely accepted as an antitumor drug as it effectively inhibits the cell cycle. This study predominantly explores the possible molecule mechanism of paclitaxel on oral cancer treatment. Cell viability was first detected using an MTT assay. Cell apoptosis was examined by Hoechst staining and flow cytometry using an annexin-V and propidium iodide kit. Specific EGFR signaling pathways were further explored through western blot analysis. Abnormal protein expression levels were determined via immunofluoresence. Additionally, the protein levels of matrix metalloproteinase (MMP)-2 and 9 were determined using ELISA. Paclitaxel significantly inhibited oral cancer cell viability in a time- and dose-dependent manner. Paclitaxel also enhanced oral cancer cell apoptosis via increased Bim and Bid protein expression. Furthermore, paclitaxel was observed to inhibit oral cancer cell proliferation through increased MMP-2 and MMP-9 protein levels. Paclitaxel inhibited the growth of the oral cancer cell line, tea8113 malignant proliferation and enhanced tea8113 cell apoptosis through inhibiting the EGFR signaling pathway.

HBx induced AFP receptor expressed to activate PI3K/AKT signal to promote expression of Src in liver cells and hepatoma cells

BACKGROUND

Hepatitis B virus (HBV)-X protein(HBx) is a transactivator of host several cellular genes including alpha-fetoprotein(AFP) and AFP receptor(AFPR) which contributes to HBV-associated tumor development. The expression of AFP/AFPR are correlated with hepatocellular carcinoma(HCC)-initial cells. But the role of AFP and AFPR in promoting occurrence of HBV-related HCC were still unclear.

METHODS

A total of 71 clinical patients' liver specimens, normal human liver cells L-02 and HCC cell lines, PLC/PRF/5 were selected for analyzing the effects of HBx on expression of AFP, AFPR and Src. The expression of goal proteins were detected by Immunohistochemical stained and Western blotting; HBx-expressed vectors were constructed and transfected into L-02 cells, laser confocal microscopy was applied to observe expression and location of AFP, AFPR and Src in the normal liver cells and HCC cells, soft agar colony formation assay was used to observe colonies formed of the cells.

RESULTS

We confirmed HBx gives preference to promote the expression of AFP and AFPR; HBx priors to up-regulate the expression of AFPR and AFP in L-02 cells and in normal liver specimens; AFPR signal been able to stimulate Src expression. The results also indicated that phosphatidylinositol 3-kinase(PI3K) inhibitors Ly294002 and GDC0941 effectively suppress AFPR mediated up-regulation expression of Src in AFPR positive HCC lines.

CONCLUSIONS

HBx priors to drive the expression of AFP and AFPR to promote expression of Src in normal liver cells and hepatoma cells; AFP and AFPR maybe play pivotal role in HBV-related hepatocarcinogenesis; Targeting AFPR is an available therapeutic strategy of HCC.

Telomerase inhibition decreases alpha-fetoprotein expression and secretion by hepatocellular carcinoma cell lines: in vitro and in vivo study

Alpha-fetoprotein (AFP) is a diagnostic marker for hepatocellular carcinoma (HCC). A direct relationship between poor prognosis and the concentration of serum AFP has been observed. Telomerase, an enzyme that stabilizes the telomere length, is expressed by 90% of HCC. The aim of this study was to investigate the effect of telomerase inhibition on AFP secretion and the involvement of the PI3K/Akt/mTOR signaling pathway. Proliferation and viability tests were performed using tetrazolium salt. Apoptosis was determined through the Annexin V assay using flow cytometry. The concentrations of AFP were measured using ELISA kits. The AFP mRNA expression was evaluated using RT-PCR, and cell migration was evaluated using a Boyden chamber assay. The in vivo effect of costunolide on AFP production was tested in NSG mice. Telomerase inhibition by costunolide and BIBR 1532 at 5 and 10 μM decreased AFP mRNA expression and protein secretion by HepG2/C3A cells. The same pattern was obtained with cells treated with hTERT siRNA. This treatment exhibited no apoptotic effect. The AFP mRNA expression and protein secretion by PLC/PRF/5 was decreased after treatment with BIBR1532 at 10 μM. In contrast, no effect was obtained for PLC/PRF/5 cells treated with costunolide at 5 or 10 μM. Inhibition of the PI3K/Akt/mTOR signaling pathway decreased the AFP concentration. In contrast, the MAPK/ERK pathway appeared to not be involved in HepG2/C3A cells, whereas ERK inhibition decreased the AFP concentration in PLC/PRF/5 cells. Modulation of the AFP concentration was also obtained after the inhibition or activation of PKC. Costunolide (30 mg/kg) significantly decreased the AFP serum concentration of NSG mice bearing HepG2/C3A cells. Both the inhibition of telomerase and the inhibition of the PI3K/Akt/mTOR signaling pathway decreased the AFP production of HepG2/C3A and PLC/PRF/5 cells, suggesting a relationship between telomerase and AFP expression through the PI3K/Akt/mTOR pathway.

Alpha-fetoprotein activates AKT/mTOR signaling to promote CXCR4 expression and migration of hepatoma cells

CXCR4, stromal cell-derived factor-1α(SDF 1α) receptor, stimulates growth and metastasis of hepatocellular carcinoma (HCC). Alpha-fetoprotein(AFP) governs the expression of some metastasis-related genes. Here we report that AFP and CXCR4 levels correlated in HCC tissues. AFP-expressing vectors induced CXCR4. In agreement, AFP depletion by siRNA decreased CXCR4. AFP co-localized and interacted with PTEN, thus inducing CXCR4 by activating AKT(Ser473) phosphorylation. In turn, phospho-mTOR(Ser2448) entered the nucleus and bound the CXCR4 gene promoter. Thus, AFP promoted migration of HCC cells. In concusion, AFP induced CXCR4 by activating the AKT/mTOR signal pathway.

Effect of pre- and post-treatment α-fetoprotein levels and tumor size on survival of patients with hepatocellular carcinoma treated by resection, transarterial chemoembolization or radiofrequency ablation: a retrospective study

Background

We evaluated treatment modalities and survival in patients with hepatocellular carcinoma (HCC), by pre-treatment and 3-month post-treatment serum alpha-fetoprotein (AFP) levels and pre-treatment tumor diameters.

Methods

We retrospectively reviewed 57 patients treated for HCC in our department from January 2002 to December 2012, including their sex, type of hepatitis, Child class, pre-treatment tumor size, pre-treatment levels of albumin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyltransferase (GGT), red blood cells, hemoglobin, and total bilirubin, pre- and 3-month post-treatment serum AFP, and treatment modality (transarterial chemoembolization, resection or radiofrequency ablation). Survival was analyzed at 1, 3, and 5 years after treatment.

Results

The 57 patients included 44 men and 13 women, of whom 44 had hepatitis C virus (HCV) infection, 3 had hepatitis B virus (HBV) infection, 3 had both HBV and HCV infection, 1 had both HBV and hepatitis D virus infection, and 3 had alcohol-related liver cirrhosis. Both pre- and post-treatment serum AFP levels significantly correlated with recurrent tumor size (P < 0.05 for both). Pre-treatment tumor size did not correlate with recurrent tumor size. Patients who underwent hepatic resection survived significantly longer than those who underwent transarterial chemoembolization or radiofrequency ablation (P < 0.05).

Conclusions

Serum AFP level is useful in diagnosing tumor recurrence and predicting prognosis in HCC patients treated by hepatic resection, transarterial chemoembolization, and radiofrequency ablation. Hepatic resection remains the treatment of choice for HCC in suitable patients.

Two-stage model of chemically induced hepatocellular carcinoma in mouse

The aim of this study was to develop an efficient and reproducible mouse model for hepatocellular carcinoma (HCC) research and assess the expression of two proto-oncogenes (c-myc and N-ras) and tumor suppressor gene p53 in the carcinogenic process. In this study, we found that diethylnitrosamine initiation with CCl4 and ethanol promotion could induce a short-term, two-stage liver carcinogenesis model in male BALB/c mice, the process of hepatocarcinogenesis including liver damage, liver necrosis/cell death, liver inflammation, liver proliferation, liver hyperplasia, liver steatosis, and liver cirrhosis and hepatocellular nodules, which mimicked the usual sequence of events observed in human HCC. We also identified that the increase in expression of the p53 gene is related to the proliferation of hepatocytes, whereas overexpression of the c-myc and N-ras genes is associated with hepatocarcinogenesis. This animal model may serve as a basis for recapitulating the molecular pathogenesis of HCC seen in humans.

Silencing alpha-fetoprotein inhibits VEGF and MMP-2/9 production in human hepatocellular carcinoma cell

Alpha-fetoprotein not only serves as a diagnostic marker for liver cancer, but also posses a variety of biological functions. However, the role of Alpha-fetoprotein on tumor angiogenesis and cell invasion remains incompletely understood. In this study, we aimed to evaluate if Alpha-fetoprotein can regulate the major angiogenic factors and matrix metalloproteinases in human liver cancer cells. Alpha-fetoprotein silencing was achieved by Stealth RNAi. Expression of Alpha-fetoprotein was examined by a full-automatic electrochemistry luminescence immunity analyzer. Expression of VEGF, VEGFR-2, MMP-9, and MMP-2 was examined by Western blot and immunocytochemistry. Apoptosis was detected by TUNEL assay. Angiogenesis was detected by in vitro angiogenesis assay kit. Silencing of Alpha-fetoprotein led to an increased apoptosis, which was associated with a decreased expression of vascular endothelial growth factor, vascular endothelial growth factor receptor 2, matrix metalloproteinases-2/9. These results suggest that Alpha-fetoprotein may play a regulatory role on angiogenesis and cell invasion during liver cancer development.

Effects of AFP-activated PI3K/Akt signaling pathway on cell proliferation of liver cancer

This study aims to investigate effects of alpha-fetoprotein (AFP)-activated phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling pathway on hepatocellular carcinoma cell proliferation. Active cirrhosis patients after hepatitis B infection (n = 20) and viral hepatitis patients with hepatocellular carcinoma (HCC) (n = 20) were selected as the subjects of the present study. Another 20 healthy subjects were selected as the control group. The serum AFP expression and liver tissue PI3K and Akt gene mRNA expression were detected. The hepatoma cell model HepG2 which had a stable expression of AFP gene was used. Real-time quantitative PCR and Western blot and other methods were used to analyze the intracellular PI3K and Akt protein levels. Compared with control group and cirrhosis group, the serum AFP levels in HCC group significantly increased, and the tissue PI3K and Akt mRNA expression also significantly increased. HepG2 cells were intervened using AFP, in which the PIK and Akt protein expression significantly increased. After intervention by use of AFP monoclonal antibodies or LY294002 inhibitor, the PIK and Akt protein expression in HepG2 cell was significantly decreased (P < 0.05). AFP can promote the proliferation of hepatoma cells via activation of PI3K/Akt signaling pathway.

Clinical significance of the thymidylate synthase, dihydropyrimidine dehydrogenase, and thymidine phosphorylase mRNA expressions in hepatocellular carcinoma patients receiving 5-fluorouracil-based transarterial chemoembolization treatment

Purpose

To determine whether 5-fluorouracil (5-FU) sensitivity is associated with the mRNA expressions of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), and thymidine phosphorylase (TP) in patients with hepatocellular carcinoma (HCC) treated with 5-FU-based transarterial chemoembolization (TACE).

Methods

Formalin-fixed, paraffin-embedded tumor specimens from 40 patients treated with 5-FU-based TACE were selected for the examination of TS, DPD, and TP expression level by a quantitative real-time reverse transcription- polymerase chain reaction (PCR) technique. Patients were categorized into high and low expression groups according to the median expression level of each enzyme. Associations between the mRNA expression levels of TS, DPD, and TP and clinical parameters including treatment efficacies, clinicopathological factors, and prognosis were assessed.

Results

High DPD expression was associated with worse treatment outcome, including intrahepatic disease progression rate (hazard ratio [HR] for high DPD versus low DPD, 2.212; 95% confidence interval [CI], 1.030–4.753; P = 0.042), extrahepatic disease progression rate (HR for high versus low DPD, 3.171; 95% CI, 1.003–10.023; P = 0.049), and progression-free survival (HR for high versus low DPD, 2.308; 95% CI, 1.102–4.836; P = 0.027). No correlation was found between the mRNA expression of TS/TP and treatment outcome.

Conclusion

DPD mRNA expression level was negatively correlated with the clinical outcomes of HCC patients treated with 5-FU-based TACE. These results provide indirect evidence that high DPD mRNA expression is a predictive marker of treatment resistance for 5-FU.

Alpha-fetoprotein: a renaissance

Alpha-fetoprotein (AFP) is a major mammalian embryo-specific and tumor-associated protein that is also present in small quantities in adults at normal conditions. Discovery of the phenomenon of AFP biosynthesis in carcinogenesis by G. Abelev and Yu. Tatarinov 50 years ago, in 1963, provoked intensive studies of this protein. AFPs of some mammalian species were isolated, purified and physico-chemically and immunochemically characterized. Despite the significant success in study of AFP, its three-dimensional structure, mechanisms of receptor binding along with a structure of the receptor itself and, what is the most important, its biological role in embryo- and carcinogenesis remain still obscure. Due to difficulties linked with methodological limitations, research of AFP was to some extent extinguished by the 1990 s. However, over the last decade a growing number of investigations of AFP and its usage as a tumor-specific biomarker have been observed. This was caused by the use of new technologies, primarily, computer-based and genetic engineering approaches in studying of this very important oncodevelopmental protein. Our review summarizes efforts of different scientific groups throughout the world in studying AFP for 50 years with emphasis on detailed description of recent achievements in this field.

Risk factors of poor prognosis and portal vein tumor thrombosis after curative resection of solitary hepatocellular carcinoma

BACKGROUND

Predictors of poor prognosis of solitary hepatocellular carcinoma (SHCC), a subgroup encompassing most patients with the malignancy, are still controversial. Hence, risk factors for portal vein tumor thrombosis (PVTT) in SHCC are obscure. The present study was designed to address this issue.

METHOD

Clinicopathological and follow-up data for 156 consecutive patients with SHCC following curative hepatic resection were analyzed using uni- and multi-variate analyses.

RESULTS

Univariate analysis showed that PVTT, tumor-node-metastasis (TNM) stage, Edmondson-Steiner grade and preoperative serum alpha-fetoprotein (AFP) level were associated with the overall and disease-free survival, whereas tumor size only influenced the overall survival. In multivariate Cox regression tests, Edmondson-Steiner grade and TNM stage were independent prognostic markers for both overall and disease-free survival. In addition, the Chi-square test showed that AFP level and Edmondson-Steiner grade were correlated with PVTT. Among them, only Edmondson-Steiner grade was shown to be of independent significance for PVTT in multi-variate logistic regression analysis. Additionally, AFP, the sole preoperative factor for PVTT, was not adequately sensitive and specific.

CONCLUSIONS

Factors relating to post-surgical prognosis and PVTT in SHCC are all tumor-related. Of these, Edmondson-Steiner grade and TNM stage might be of particular importance in survival analysis. In addition, accurate prediction of PVTT by clinicopathological parameters before surgery remains difficult.

Regression of hepatocarcinoma cells using RNA aptamer specific to alpha-fetoprotein

Alpha-fetoprotein (AFP) is a cancer-associated fetal protein and has long been utilized as a serum fetal defect/tumor marker to monitor distress/disease progression. In addition, AFP is closely associated with the proliferation of hepatocellular carcinoma. Thus, direct targeting of AFP has been recommended for a therapeutic strategy against hepatocellular carcinoma. In this study, we developed and characterized an RNA aptamer that specifically bound to the alpha-fetoprotein using SELEX technology. The aptamer interacted with the AFP with a K(D) of ∼33 nM. Importantly, the identified aptamer specifically and efficiently inhibited the AFP-mediated proliferation of hepatocarcinoma cells in a dose dependent manner. Moreover, the aptamer efficiently down-regulated AFP-induced expression of oncogenes in the cells. These results indicate that an AFP-specific RNA aptamer could be a useful therapeutic and diagnostic agent against AFP-related hepatocellular carcinoma.

Elevated serum alpha fetoprotein levels promote pathological progression of hepatocellular carcinoma

AIM: To investigate the biological role of alpha fetoprotein (AFP) and its clinical significance in carcinogenesis of hepatocellular carcinoma (HCC).

METHODS: Clinical analysis of HCC patients and immunohistochemical examination were conducted to evaluate the relationship between serum AFP level and patient mortality. Confocal microscopy, Western blotting, dimethylthiahzolyl-2,5-diphenyl-tetrazolium bromide, Cell Counting Kit-8 assays and flow cytometry were performed to explore the possible mechanism.

RESULTS: Among the 160 HCC patients enrolled in this study, 130 patients survived 2 years (81.25%), with a survival rate of 86.8% in AFP < 2 0 μg/L group, 88.9% in AFP 20-250 μg/L group, and 69.6% in AFP > 250 μg/L group, demonstrating a higher mortality rate in HCC patients with higher AFP levels. Surgical treatment was beneficial only in patients with low AFP levels. The mortality rate of HCC patients with high AFP levels who were treated surgically was apparently higher than those treated with conservative management. The results of immunohistochemistry showed that AFP and AFP receptor were merely expressed in tissues of HCC patients with positive serum AFP. Consistently, in vitro analysis showed that AFP and AFPS were expressed in HepG2 but not in HLE cells. AFP showed a capability to promote cell growth, and this was more apparent in HepG2 cells, in which the proliferation was increased by 3.5 folds. Cell cycle analysis showed that the percentage of HepG2 cells in S phase after exposure to AFP was modestly increased.

CONCLUSION: HCC patients with higher AFP levels show a higher mortality rate, which appears to be attributable to the growth promoting properties of AFP.

Global gene profiling of spontaneous hepatocellular carcinoma in B6C3F1 mice: similarities in the molecular landscape with human liver cancer

Hepatocellular carcinoma (HCC) is an important cause of morbidity and mortality worldwide. Although the risk factors of human HCC are well known, the molecular pathogenesis of this disease is complex, and in general, treatment options remain poor. The use of rodent models to study human cancer has been extensively pursued, both through genetically engineered rodents and rodent models used in carcinogenicity and toxicology studies. In particular, the B6C3F1 mouse used in the National Toxicology Program (NTP) two-year bioassay has been used to evaluate the carcinogenic effects of environmental and occupational chemicals, and other compounds. The high incidence of spontaneous HCC in the B6C3F1 mouse has challenged its use as a model for chemically induced HCC in terms of relevance to the human disease. Using global gene expression profiling, we identify the dysregulation of several mediators similarly altered in human HCC, including re-expression of fetal oncogenes, upregulation of protooncogenes, downregulation of tumor suppressor genes, and abnormal expression of cell cycle mediators, growth factors, apoptosis regulators, and angiogenesis and extracellular matrix remodeling factors. Although major differences in etiology and pathogenesis remain between human and mouse HCC, there are important similarities in global gene expression and molecular pathways dysregulated in mouse and human HCC. These data provide further support for the use of this model in hazard identification of compounds with potential human carcinogenicity risk, and may help in better understanding the mechanisms of tumorigenesis resulting from chemical exposure in the NTP two-year carcinogenicity bioassay.

Long-term outcome and hepatocellular carcinoma development in chronic hepatitis B or cirrhosis patients after nucleoside analog treatment with entecavir or lamivudine

AIM

  We conducted this prospective study to elucidate the long-term outcome and incidence of hepatocellular carcinoma (HCC) development after nucleos(t)ide analog (NA) treatment in patients with chronic hepatitis B (CHB) or cirrhosis.

METHODS

  CHB or cirrhosis patients without past NA treatment or HCC were started on entecavir (ETV) or lamivudine (LVD), and prospectively followed up with monthly blood tests, and with abdominal imaging every 6 months in CHB and every 3 months in cirrhosis patients.

RESULTS

  A total of 256 subjects with CHB (n = 194) or cirrhosis (n = 62) received ETV (n = 129) or LVD (n = 127) for 4.25 years (range: 0.41-10.0). After NA treatment, serum HBV DNA, alanine aminotransferase and α-fetoprotein (AFP) dropped significantly, along with significant increases in serum albumin and prothrombin time. Drug-resistance developed in 60 cases in the LVD group and in only one case in the ETV group. HCC developed in 35 patients, and the incidence at years 1, 3, 5, 7 and 10 was significantly higher in patients with cirrhosis (8.1%, 17.5%, 43.2%, 46.7% and 53.4%, respectively) than chronic hepatitis (1.6%, 3.5%, 3.5%, 7.1% and 29.6%, respectively), with no difference between ETV and LVD. After NA treatment, the sensitivity/specificity for HCC of AFP and des-γ-carboxy prothrombin (DCP) was 45.7%/97.3% and 33.3%/96.2%, respectively, with the specificity of AFP being higher than at baseline (64.4%), at the cut-off of 10 ng/mL.

CONCLUSION

  NA exerted a long-term efficacy and improved hepatic reservation in CHB and cirrhosis. After NA treatment, AFP dropped to lower than 10 ng/mL with marked elevation of specificity, leading to an earlier detection of HCC.

Alpha-fetoprotein: a new member of intracellular signal molecules in regulation of the PI3K/AKT signaling in human hepatoma cell lines

Despite its well-defined role as a serum growth factor during fetal liver development and hepatic oncogenesis, the biological significance of cytoplasmic alpha-fetoprotein (AFP) remains incompletely understood. Here, we provide evidence to illustrate that cytoplasmic AFP may function as a regulator in the phosphatidylinositol 3-kinase (PI3K)/AKT pathway in human hepatocellular carcinoma cells. The results demonstrated colocalization and interaction of AFP and phosphatase and tensin homolog deleted on chromosome 10 (PTEN) in the cytoplasm of AFP-producing Bel 7402 and HepG2 cells, with an interaction distance of 12.6 ± 2.7 Å as determined with the fluorescence resonance energy transfer technique. Knockdown of AFP mRNA or inhibition of AFP expression by all trans-retinoic acid resulted in enhancement of the PTEN level with a synchronous decrease in phosphorylated AKT. Transfection of the afp gene into HLE cells (originally AFP negative) led to a significant activation of AKT signaling. The inhibition of PI3K signaling by LY 294002 was simultaneously reversed by transfection, accompanied by diminution of all trans-retinoic acid-induced upregulation of PTEN and enhancement of cell growth. In conclusion, these results demonstrate that cytoplasmic AFP is involved in regulation of hepatocellular growth and tumorigenesis.

Serum alpha-fetoprotein levels during and after interferon therapy and the development of hepatocellular carcinoma in patients with chronic hepatitis C

The association between serum alpha-fetoprotein (AFP) levels during and after interferon (IFN) therapy and the development of hepatocellular carcinoma (HCC) was evaluated in patients with chronic hepatitis C (CHC). A total of 263 patients treated by IFN with or without ribavirin were enrolled in the study. Serum AFP levels during and after IFN therapy were investigated retrospectively, and statistical analysis was performed to identify the factors associated with HCC development. During IFN therapy, serum AFP levels significantly decreased, regardless of virologic response to treatment. Increased serum AFP levels (>or=10 ng/ml) at the end of IFN therapy (EOT) was a close-to-significant variable affecting the development of HCC (P = 0.057), and a significantly higher cumulative incidence of HCC was seen in patients with increased serum AFP levels at EOT (P = 0.021). Serum AFP level at EOT is a possible predictor of HCC in CHC patients after IFN therapy.

Cytoplasmic alpha-fetoprotein functions as a co-repressor in RA-RAR signaling to promote the growth of human hepatoma Bel 7402 cells

The role of AFP in the retinoic acid-RAR signaling pathway was investigated in human hepatoma Bel 7402 cells. The results showed that AFP and RAR-beta were co-localized and interacted in cytoplasm. AFP may inhibit translocation of RAR-beta into the nucleus via competitive binding to RAR-beta with ATRA, which was reversed by AFP-siRNA transfection. Our data suggest that the ATRA resistance of Bel 7402 cells is at least in part attributable to their high level of cytoplasmic AFP. Thus, by counteracting the effect of AFP, it may be possible to increase the sensitivity of tumor cells to ATRA.

Alpha fetoprotein is a novel protein-binding partner for caspase-3 and blocks the apoptotic signaling pathway in human hepatoma cells

Although there is increasing evidence that alpha fetoprotein (AFP) may function as regulatory factor in the growth of tumor cells, the precise mechanism is still unclear. In the current study, we investigated the role of the cytoplasmic AFP in caspase-3-mediated signaling of apoptosis. Our results showed that low doses of TNF-related apoptosis-inducing ligand (TRAIL) elevated the activity of caspase-8, but not caspase-3. Caspase-3 colocalized and interacted with AFP in the cytoplasm of Bel 7402 cells, and translocated into nuclei in association with the occurrence of apoptosis while cells were under cotreatment with all-trans retinoic acid (ATRA) or TRAIL. AFP was able to form complexes with caspase-3 and block onward transmission of signaling from caspase-8. Knockdown of AFP increased the sensitivity of Bel 7402 cells to TRAIL, and thereby, triggered caspase-3 signaling. No intermolecule interaction occurred between AFP and caspase-8, nor was caspase-8 activity altered after AFP knockdown, demonstrating the selectivity of AFP in interfering with the apoptotic signaling pathway. The effect of AFP on caspase-3 was further confirmed by transfection of the AFP gene into HLE cells (AFP negative). We conclude that ATRA or TRAIL resistance in AFP producing hepatoma is at least, in part, attributable to the high level of the cytoplasmic AFP. Therefore, it is possible that the combination of AFP gene silencing together with ATRA/TRAIL cotreatment will benefit the enhancement of the chemotherapeutic efficiency of these agents on tumors.

Silencing alpha-fetoprotein expression induces growth arrest and apoptosis in human hepatocellular cancer cell

The expression of alpha-fetoprotein (AFP), a tumor-associated antigen, is silenced in normal adult hepatocyte but reactivated in human hepatocellular carcinoma (HCC). To investigate the roles of AFP in the regulation of cell growth, we silenced AFP expression in the HCC cell line Huh7 by transfection of specific Stealth RNAi. After the transfection for 48 h, the expression of AFP gene was almost abolished, the cell proliferation was inhibited by 46.15%, and the number of cells undergoing early apoptosis was significantly increased to 63.93%. Inhibition of AFP expression also resulted in an increased in Bax/Bcl-2 ratio, the release of cytochrome c from mitochondria and activation of caspase-3. The results suggest that AFP may positively regulate cell proliferation by enhancing the apoptosis resistance via dysfunction of the p53/Bax/cytochrome c/caspase-3 signaling pathway in AFP-producing HCC cell line. As such, the knockdown of AFP gene should be further investigated in vivo as a novel approach to HCC treatment.

alpha-Fetoprotein shields hepatocellular carcinoma cells from apoptosis induced by tumor necrosis factor-related apoptosis-inducing ligand

The interference of alpha-fetoprotein (AFP) with the apoptosis induced by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in Bel 7402 cells was investigated in the current study. The results showed a moderate degree of drug-resistance of Bel 7402 cells to TRAIL. The caspase-3 cascade was the main pathway involved in TRAIL-induced apoptosis, which was virtually abolished in the presence of AFP. TRAIL together with antibody against AFP was able to accelerate the death of tumor cells. This study suggests the possibility a therapeutic strategy for improving clinical treatment of liver tumor with TRAIL could be effected through antagonizing the shelter effect of AFP.

Review of Growth Inhibitory Peptide as a biotherapeutic agent for tumor growth, adhesion, and metastasis

This review surveys the biological activities of an alpha-fetoprotein (AFP) derived peptide termed the Growth Inhibitory Peptide (GIP), which is a synthetic 34 amino acid segment produced from the full length 590 amino acid AFP molecule. The GIP has been shown to be growth-suppressive in both fetal and tumor cells but not in adult terminally-differentiated cells. The mechanism of action of this peptide has not been fully elucidated; however, GIP is highly interactive at the plasma membrane surface in cellular events such as endocytosis, cell contact inhibition and cytoskeleton-induced cell shape changes. The GIP was shown to be growth-suppressive in nine human tumor types and to suppress the spread of tumor infiltrates and metastases in human and mouse mammary cancers. The AFP-derived peptide and its subfragments were also shown to inhibit tumor cell adhesion to extracellular matrix (ECM) proteins and to block platelet aggregation; thus it was expected that the GIP would inhibit cell spreading/migration and metastatic infiltration into host tissues such as lung and pancreas. It was further found that the cyclic versus linear configuration of GIP determined its biological and anti-cancer efficacy. Genbank amino acid sequence identities with a variety of integrin alpha/beta chain proteins supported the GIP's linkage to inhibition of tumor cell adhesion and platelet aggregation. The combined properties of tumor growth suppression, prevention of tumor cell-to-ECM adhesion, and inhibition of platelet aggregation indicate that tumor-to-platelet interactions present promising targets for GIP as an anti-metastatic agent. Finally, based on cholinergic studies, it was proposed that GIP could influence the enzymatic activity of membrane acetylcholinesterases during tumor growth and metastasis. It was concluded that the GIP derived from full-length AFP represents a growth inhibitory motif possessing instrinsic properties that allow it to interfere in cell surface events such as adhesion, migration, metastasis, and aggregation of tumor cells.

Downregulation of alpha-fetoprotein siRNA inhibits proliferation of SMMC-7721 cells

AIM: To study the function of a-fetoprotein (AFP) in SMMC-7721 hepatoma cells.

METHODS: A hairpin siRNA expressing plasmid pSilencer3.0-H1-afp was constructed andtransfected into SMMC-7721 cells with Lipofectamine 2000. The expression of AFP was monitored by real-time RT-PCR and immunoassays, its effect on SMMC-7721 cell proliferation and cell death was detected by MTT and fluorescence- activated cell sorter (FACS).

RESULTS: The AFP-siRNA expressing plasmid downregulated the expression of AFP obviously (about 34%), and inhibited SMMC-7721 cell proliferation, but did not induce apoptosis.

CONCLUSION: Downregulation of AFP siRNA inhibits proliferation of SMMC-7721 cells, but cannot cause apoptosis.

Gene knockdown by large circular antisense for high-throughput functional genomics

Single-stranded genomic DNA of recombinant M13 phages was tested as an antisense molecule and examined for its usefulness in high-throughput functional genomics. cDNA fragments of various genes (TNF-alpha, c-myc, c-myb, cdk2 and cdk4) were independently cloned into phagemid vectors. Using the life cycle of M13 bacteriophages, large circular (LC)-molecules, antisense to their respective genes, were prepared from the culture supernatant of bacterial transformants. LC-antisense molecules exhibited enhanced stability, target specificity and no need for target-site searches. High-throughput functional genomics was then attempted with an LC-antisense library, which was generated by using a phagemid vector that incorporated a unidirectional subtracted cDNA library derived from liver cancer tissue. We identified 56 genes involved in the growth of these cells. These results indicate that an antisense sequence as a part of single-stranded LC-genomic DNA of recombinant M13 phages exhibits effective antisense activity, and may have potential for high-throughput functional genomics.