Glycolysis Inhibition as a Strategy for Hepatocellular Carcinoma Treatment?

Hepatocellular carcinoma (HCC) is the most frequently detected primary malignant liver tumor, representing a worldwide public health problem due to its high morbidity and mortality rates. The HCC is commonly detected in advanced stage, precluding the use of treatments with curative intent. For this reason, it is crucial to find effective therapies for HCC. Cancer cells have a high dependence of glycolysis for ATP production, especially under hypoxic environment. Such dependence provides a reliable possible strategy to specifically target cancer cells based on the inhibition of glycolysis. HCC, such as other cancer types, presents a clinically well-known upregulation of several glycolytic key enzymes and proteins, including glucose transporters particularly glucose transporter 1 (GLUT1). Such enzymes and proteins constitute potential targets for therapy. Indeed, for some of these targets, several inhibitors were already reported, such as 2-Deoxyglucose, Imatinib or Flavonoids. Although the inhibition of glycolysis presents a great potential for an anticancer therapy, the development of glycolytic inhibitors as a new class of anticancer agents needs to be more explored. Herein, we propose to summarize, discuss and present an overview on the different approaches to inhibit the glycolytic metabolism in cancer cells, which may be very effective in the treatment of HCC.

Oxidative Stress, DNA, Cell Cycle/Cell Cycle Associated Proteins and Multidrug Resistance Proteins: Targets of Human Amniotic Membrane in Hepatocellular Carcinoma.

The anticancer effects of human amniotic membrane (hAM) have been studied over the last decade. However, the action mechanisms responsible for these effects are not fully understood until now. Previously results reported by our team proved that hAM is able to induce cytotoxicity and cell death in hepatocellular carcinoma (HCC), a worldwide high incident and mortal cancer. Therefore, this experimental study aimed to investigate the cellular targets of hAM protein extracts (hAMPE) in HCC through in vitro studies. Our results showed that hAMPE is able to modify oxidative stress environment in all HCC cell lines, as well as its cell cycle. hAMPE differently targets deoxyribonucleic acid (DNA), P21, P53, ß-catenin and multidrug resistance (MDR) proteins in HCC cell lines. In conclusion, hAMPE has several targets in HCC, being clear that the success of this treatment depends of a personalized therapy based on the biological and genetic characteristics of the tumor.

Selective cytotoxicity and cell death induced by human amniotic membrane in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) has a worldwide high incidence and mortality. For this reason, it is essential to invest in new therapies for this type of cancer. Our team already proved that human amniotic membrane (hAM) is able to inhibit the metabolic activity of several human cancer cell lines, including HCC cell lines. Taking into account the previously performed work, this experimental study aimed to investigate the pathways by which hAM protein extracts (hAMPEs) act on HCC. Our results showed that hAMPE reduce the metabolic activity, protein content and DNA content in a dose- and time-dependent manner in all HCC cell lines. This therapy presents selective cytotoxicity, since it was not able to inhibit a non-tumorigenic human cell line. In addition, hAMPE induced cell morphology alterations in all HCC cell lines, but death type is cell line dependent, as proved by in vitro and in vivo studies. In conclusion, hAMPE have a promising role in HCC therapy, since it is capable of inducing HCC cytotoxicity and cell death.

Beyond the limits of oxygen: effects of hypoxia in a hormone-independent prostate cancer cell line.

Prostate cancer (PCa) has a high incidence worldwide. One of the major causes of PCa resistance is intratumoral hypoxia. In solid tumors, hypoxia is strongly associated with malignant progression and resistance to therapy, which is an indicator of poor prognosis. The antiproliferative effect and induced death caused by doxorubicin, epirubicin, cisplatin, and flutamide in a hormone-independent PCa cell line will be evaluated. The hypoxia effect on drug resistance to these drugs, as well as cell proliferation and migration, will be also analyzed. All drugs induced an antiproliferative effect and also cell death in the cell line under study. Hypoxia made the cells more resistant to all drugs. Moreover, our results reveal that long time cell exposure to hypoxia decreases cellular proliferation and migration. Hypoxia can influence cellular resistance, proliferation, and migration. This study shows that hypoxia may be a key factor in the regulation of PCa.

Hepatocellular carcinoma and chemotherapy: the role of p53.

BACKGROUND: Hepatocellular carcinoma (HCC) is the most common primary neoplasm of the liver. A major proportion of HCCs also present mutation of the gene that encodes p53, which confers chemoresistance. The main goal of this work is to investigate the effect of cisplatin, doxorubicin and 5-fluoruracil (5-FU) in three human HCC cell lines which differ in p53 expression. METHODS: HepG2 (expressing normal p53), HuH7 (expressing mutated p53) and Hep3B2.1-7 (not expressing p53) cell lines were cultivated in the presence of cisplatin, doxorubicin and 5-FU. Cell proliferation was evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay (MTT assay). The type of cell death and Bax and Bcl2 activation were assessed by flow cytometry. RESULTS: It was found that for all of the cell lines studied, the agent that gave the most satisfactory results was doxorubicin. 5-FU demonstrated no activity in these cell lines. CONCLUSIONS: For all the cell lines studied, doxorubicin was the most satisfactory agent. In HepG2 and HuH7 cell lines, it can activate Bax with statistical significance.

Amniotic membrane: from structure and functions to clinical applications.

Amniotic membrane (AM) or amnion is a thin membrane on the inner side of the fetal placenta; it completely surrounds the embryo and delimits the amniotic cavity, which is filled by amniotic liquid. In recent years, the structure and function of the amnion have been investigated, particularly the pluripotent properties of AM cells, which are an attractive source for tissue transplantation. AM has anti-inflammatory, anti-bacterial, anti-viral and immunological characteristics, as well as anti-angiogenic and pro-apoptotic features. AM is a promoter of epithelialization and is a non-tumorigenic tissue and its use has no ethical problems. Because of its attractive properties, AM has been applied in several surgical procedures related to ocular surface reconstruction and the genito-urinary tract, skin, head and neck, among others. So far, the best known and most auspicious applications of AM are ocular surface reconstruction, skin applications and tissue engineering. However, AM can also be applied in oncology. In this area, AM can prevent the delivery of nutrients and oxygen to cancer cells and consequently interfere with tumour angiogenesis, growth and metastasis.

Radiolabelling of ascorbic acid: a new clue to clarify its action as an anticancer agent?

Vitamin C exists in two forms: the reduced (ascorbic acid--AA) and oxidized form (dehydroascorbic acid--DHA). This is a nutrient whose benefits are long known and widely publicized, being most of them related to its antioxidant action. As an antioxidant, the main role of vitamin C is to neutralize free radicals, reducing oxidative stress. However, some controversial studies suggest that this nutrient may have a preventive and therapeutic role in cancer disease due to their possible pro-oxidant activity, promoting the formation of reactive oxygen species that can induce cell death in cancer cells. This factor, coupled with the decrease of antioxidant enzymes and increase of decompartmentalized transition metals in tumor cells may result in the selective cytotoxicity of vitamin C and the subsequent revelation of its therapeutic potential. In this way the first purpose of this work was radioactively label the reduced form of vitamin C with Tc-99m, its quality control by HPLC and the time stability. The second purpose was to use the radioactive complex 99mTc-AA in in vitro and in vivo studies in order to evaluate its uptake by colorectal cancer cells and biodistribution in mices, respectively. The results suggest that the pharmaceutical formulation developed, which was reproducible and stable over time, was residually taken up by colorectal cancer cells. Future studies are needed to deepen our understanding about the radioactive complex 99mTc-AA and clarify the mechanisms of action of vitamin C in oncologic disease.