licochalcone-a and Colonic-Neoplasms

Hypoxia-inducible factor (HIF)-1 is an important regulator of the cellular response in the hypoxic tumor environment. While searching for HIF inhibitors derived from natural products that act as anticancer agents, we found that Glycyrrhiza uralensis exerts HIF-1 inhibitory activity in hypoxic cancer cells. Among the five components of G. uralensis, licochalcone A was found to potently suppress hypoxia-induced HIF-1α accumulation and expression of HIF-1α target genes, including GLUT1 and PDK1 in HCT116 cells. Licochalcone A also enhances intracellular oxygen content by directly inhibiting mitochondrial respiration, resulting in oxygen-dependent HIF-1α degradation. Hence, licochalcone A may effectively inhibit ATP production, primarily by reducing the mitochondrial respiration-mediated ATP production rate rather than the glycolysis-mediated ATP production rate. This effect subsequently suppresses cancer cell viability, including that of HCT116, H1299, and H322 cells. Consequently, these results suggest that licochalcone A has therapeutic potential in hypoxic cancer cells.

Topics: Adenosine Triphosphate; Antineoplastic Agents, Phytogenic; Cell Proliferation; Cell Survival; Chalcones; Colonic Neoplasms; Gene Expression Regulation, Neoplastic; HCT116 Cells; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Mitochondria; Signal Transduction; Tumor Hypoxia; Tumor Microenvironment

Glycyrrhiza glabra L., a traditional medicinal, has a history of thousands of years. It is widely used in clinic and has been listed in Chinese Pharmacopoeia. Licochalcone A is a phenolic chalcone compound and a characteristic chalcone of Glycyrrhiza glabra L. It has many pharmacological activities, such as anti-cancer, anti-inflammatory, anti-viral and anti-angiogenic activities.. In this study, we explored the anti-tumor activity and potential mechanism of licochalcone A in vitro and in vivo.. In vitro, the mechanism of licochalcone A at inhibiting PD-L1 expression was investigated by molecular docking, western blotting, RT-PCR, flow cytometry, immunofluorescence and immunoprecipitation assays. The co-culture model of T cells and tumor cells was used to detect the activity of cytotoxic T lymphocytes. Colony formation, EdU labelling and apoptosis assays were used to detect changes in cellular proliferation and apoptosis. In vivo, anti-tumor activity of licochalcone A was assessed in a xenograft model of HCT116 cells.. In the present study, we found that licochalcone A suppressed the expression of programmed cell death ligand-1 (PD-L1), which plays a key role in regulating the immune response. In addition, licochalcone A inhibited the expressions of p65 and Ras. Immunoprecipitation experiment showed that licochalcone A suppressed the expression of PD-L1 by blocking the interaction between p65 and Ras. In the co-culture model of T cells and tumor cells, licochalcone A pretreatment enhanced the activity of cytotoxic T lymphocytes and restored the ability to kill tumor cells. In addition, we showed that licochalcone A inhibited cell proliferation and promoted cell apoptosis by targeting PD-L1. In vivo xenograft assay confirmed that licochalcone A inhibited the growth of tumor xenografts.. In general, these results reveal the previously unknown properties of licochalcone A and provide new insights into the anticancer mechanism of this compound.

Topics: Animals; Antineoplastic Agents, Phytogenic; B7-H1 Antigen; Cell Proliferation; Chalcones; Coculture Techniques; Colonic Neoplasms; Gene Expression Regulation, Neoplastic; HCT116 Cells; Humans; MAP Kinase Kinase Kinases; Mice; Mice, Nude; Neoplasms, Experimental; NF-kappa B; raf Kinases; ras Proteins; T-Lymphocytes

The c-Jun N-terminal kinases (JNK) play an important role in many physiologic processes induced by numerous stress signals. Each JNK protein appears to have a distinct function in cancer, diabetes, or Parkinson's disease. Herein, we found that licochalcone A, a major phenolic constituent isolated from licorice root, suppressed JNK1 activity but had little effect on JNK2 in vitro activity. Although licochalcone A binds with JIP1 competitively with either JNK1 or JNK2, a computer simulation model showed that after licochalcone A binding, the ATP-binding cleft of JNK1 was distorted more substantially than that of JNK2. This could reduce the affinity of JNK1 more than JNK2 for ATP binding. Furthermore, licochalcone A inhibited JNK1-mediated, but not JNK2-mediated, c-Jun phosphorylation in both ex vivo and in vitro systems. We also observed that in colon and pancreatic cancer cell lines, JNK1 is highly expressed compared with normal cell lines. In cancer cell lines, treatment with licochalcone A or knocking down JNK1 expression suppressed colon and pancreatic cancer cell proliferation and colony formation. The inhibition resulted in G1 phase arrest and apoptosis. Moreover, an in vivo xenograft mouse study showed that licochalcone A treatment effectively suppressed the growth of HCT116 xenografts, without affecting the body weight of mice. These results show that licochalcone A is a selective JNK1 inhibitor. Therefore, we suggest that because of the critical role of JNK1 in colon cancer and pancreatic carcinogenesis, licochalcone A might have preventive or therapeutic potential against these devastating diseases.

Topics: Adaptor Proteins, Signal Transducing; Adenosine Triphosphate; Animals; Cell Adhesion; Cell Line; Cell Line, Tumor; Chalcones; Colonic Neoplasms; Computer Simulation; Enzyme Inhibitors; Fibroblasts; Glycyrrhiza; HEK293 Cells; Humans; Mice; Mice, Nude; Mitogen-Activated Protein Kinase 8; Mitogen-Activated Protein Kinase 9; Pancreatic Neoplasms; Phosphorylation; Plant Extracts; Protein Binding; Xenograft Model Antitumor Assays

To date, no antiangiogenic activity has been demonstrated for licochalcone A (LicA), a major phenolic constituent of Glycyrrhiza inflata, although it shows significant antitumor activity in human malignant cell lines. Our previous work demonstrated that LicA down-regulates inflammatory responses to lipopolysaccharide in murine macrophages. The purpose of the present study was to evaluate whether LicA inhibits angiogenesis, which is crucial for cancer development and progression. LicA significantly inhibited proliferation (20 microM), migration (5-20 microM), and tube formation (10-20 microM) of human umbilical vascular endothelial cells (HUVECs) as well as microvessel growth from rat aortic rings (10-20 microM). Furthermore, LicA significantly inhibited the growth of CT-26 colon cancer implants in BALB/c mice, with fewer CD31- and Ki-67-positive cells but more apoptotic cells. The underlying antiangiogenic mechanism of LicA correlated with down-regulation of vascular endothelial growth factor receptor (VEGFR)-2 activation. Our findings provide the first evidence that LicA inhibits angiogenesis in vitro and in vivo, perhaps by blocking VEGF/VEGFR-2 signaling. Inhibition of tumor growth may be attributed, at least in part, to decreased angiogenesis in LicA-treated mice. These findings emphasize the potential use of LicA against tumor development and progression in which angiogenesis is stimulated.

Topics: Animals; Aorta; Chalcones; Colonic Neoplasms; Endothelial Cells; Glycyrrhiza; Humans; Male; Mice; Mice, Inbred BALB C; Molecular Structure; Neoplasms, Experimental; Neovascularization, Pathologic; Rats; RNA Interference; Signal Transduction; Vascular Endothelial Growth Factor Receptor-2

Although chemotherapy has an important function in the treatment of most solid tumours, its clinical applications are limited by severe side effects such as nephrotoxicity, hepatotoxicity, ototoxicity and neurotoxicity. Recently, a growing amount of attention has been focused on the investigation of the effects of chemopreventive agents on the inhibition of cancer cell growth and toxicity in combination with chemotherapeutics. The aim of this study was to determine whether licochalcone A (LCA) has the potential to serve as a beneficial supplement during cisplatin chemotherapy. We found that the administration of LCA alone significantly inhibited the size of the solid tumours in CT-26 cell-inoculated Balb/c mice, without any detectable induction of nephrotoxicity, hepatotoxicity and oxidative stress. LCA also suppressed cell proliferation by reducing DNA synthesis of CT-26 murine colon cancer cells in a dose-dependent manner. LCA did not affect the therapeutic efficacy of cisplatin. Furthermore, LCA inhibited the cisplatin-induced kidney damage characterized by increases in the serum creatinine and blood urea nitrogen, as well as the cisplatin-induced liver damage characterized by increases in the serum alanine aminotransferase and aspartate aminotransferase. The repeated oral administration of LCA prior to cisplatin treatment exerted a preventive effect on the cisplatin-mediated increases in the serum nitric oxide and the tissue lipid peroxidation levels, and recovered the depleted reduced glutathione levels in the tissues. These results suggest that supplementation with LCA may be beneficial in counteracting the side effects of cisplatin therapy in cancer patients.

Topics: Administration, Oral; Alanine Transaminase; Animals; Anticarcinogenic Agents; Antineoplastic Agents; Antioxidants; Aspartate Aminotransferases; Blood Urea Nitrogen; Cell Line, Tumor; Cell Proliferation; Cell Survival; Chalcones; Cisplatin; Colonic Neoplasms; Creatinine; Drug Therapy, Combination; Glutathione; In Vitro Techniques; Kidney; Lipid Peroxidation; Liver; Male; Mice; Mice, Inbred BALB C; Neoplasm Transplantation; Nitric Oxide; Oxidative Stress; Transplantation, Heterologous