RESUMEN
Huangqi, the dried root of Radix Astragali, is an essential herb in Traditional Chinese Medicine and has been used to promote hematopoiesis for centuries. Astragalus polysaccharide (ASPS), the bioactive compound of Huangqi, serves a crucial role in hematopoiesis. The aim of the present study was to investigate the hematopoietic effects, in particular the thrombopoietic effects, and the molecular mechanisms of ASPS using an irradiationinduced myelosuppressive mouse model. Colonyforming unit assays, flow cytometric analysis of apoptosis, ELISAs, Giemsa staining and western blotting were performed to determine the hematopoietic and antiapoptotic effects of ASPS. The results demonstrated that ASPS enhanced the recovery of red blood cells at day 21 following treatment, as well as platelets and white blood cells at day 14. In addition, ASPS promoted colony formation in all lineages (megakaryocytes, granulocyte monocytes, erythroid cells and fibroblasts). The morphological study of the bone marrow demonstrated that trilineage hematopoiesis was preserved in the ASPS and thrombopoietin (TPO)treated groups compared with the control group. The overall cellularity (mean total cell count/area) of the ASPStreated group was similar to that of the TPOtreated group. Additionally, in vitro experiments indicated that treatment with 100 µg/ml ASPS exhibited the maximum effect on colony formation. ASPS attenuated cell apoptosis in megakaryocytic cells via inhibiting the mitochondrial caspase3 signaling pathway. In conclusion, ASPS promoted hematopoiesis in irradiated myelosuppressive mice possibly via enhancing hematopoietic stem/progenitor cell proliferation and inhibiting megakaryocytes apoptosis.
Asunto(s)
Medicamentos Herbarios Chinos/química , Megacariocitos/citología , Polisacáridos/administración & dosificación , Traumatismos Experimentales por Radiación/tratamiento farmacológico , Trombocitopenia/prevención & control , Animales , Apoptosis/efectos de los fármacos , Astragalus propinquus , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Hematopoyesis/efectos de los fármacos , Hematopoyesis/efectos de la radiación , Inyecciones Intraperitoneales , Masculino , Megacariocitos/efectos de los fármacos , Megacariocitos/efectos de la radiación , Ratones , Polisacáridos/farmacología , Traumatismos Experimentales por Radiación/complicaciones , Traumatismos Experimentales por Radiación/metabolismo , Trombocitopenia/etiologíaRESUMEN
OBJECTIVE: The standard therapy for advanced hepatocellular carcinoma (HCC) is sorafenib, with most patients experiencing disease progression within 6 months. Label-retaining cancer cells (LRCC) represent a novel subpopulation of cancer stem cells (CSC). The objective was to test whether LRCC are resistant to sorafenib. METHODS: We tested human HCC derived LRCC and non-LRCC before and after treatment with sorafenib. RESULTS: LRCC derived from human HCC are relatively resistant to sorafenib. The proportion of LRCC in HCC cell lines is increased after sorafenib while the general population of cancer cells undergoes growth suppression. We show that LRCC demonstrate improved viability and toxicity profiles, and reduced apoptosis, over non-LRCC. We show that after treatment with sorafenib, LRCC upregulate the CSC marker aldehyde dehydrogenase 1 family, wingless-type MMTV-integration-site family, cell survival and proliferation genes, and downregulate apoptosis, cell cycle arrest, cell adhesion and stem cells differentiation genes. This phenomenon was accompanied by non-uniform activation of specific isoforms of the sorafenib target proteins extracellular-signal-regulated kinases and v-akt-murine-thymoma-viral-oncogene homologue (AKT) in LRCC but not in non-LRCC. A molecular pathway map for sorafenib treated LRCC is proposed. CONCLUSIONS: Our results suggest that HCC derived LRCC are relatively resistant to sorafenib. Since LRCC can generate tumours with as few as 10 cells, our data suggest a potential role for these cells in disease recurrence. Further investigation of this phenomenon might provide novel insights into cancer biology, cancer recurrence and drug resistance with important implications for the development of novel cancer therapies based on targeting LRCC.