A phase 1 study of granulocyte macrophage colony-stimulating factor (sargramostim) and escalating doses of thalidomide in patients with high-risk malignant melanoma

Radioprotective effects of dammarane sapogenins against 60 Co-induced myelosuppression in mice

Radiotherapy frequently induces failure of hematopoietic system and leads to myelosuppression. The objective of this study was to investigate the protective effect of dammarane sapogenins (DS), the hydrolysed product of the constituent ginsenosides of Panax ginseng, which are produced by gut metabolism, on radiation-induced hematopoietic injury. Mice were exposed to 3.5 Gy 60 Co γ-rays of total body radiation at a dose rate of 1.60 Gy per minute and treated with DS or granulocyte colony-stimulating factor immediately after radiation. The general condition of the mice, the peripheral blood cell counts, multiple colony forming unit (CFU) assays of hematopoietic progenitor cells, hematopoietic stem cell counts, bone marrow histology, and spleen colony forming unit counts were then investigated. Our results indicated that administration with DS could ameliorate 60 Co-irradiation induced damage and significantly increase the number of peripheral blood cells (white blood cells and platelets), 5 types of hematopoietic progenitor cells CFU (CFU-GM, CFU-E, BFU-E, CFU-Meg, and CFU-GEMM), hematopoietic stem cell (Lin- c-kit+ Scal-1+ ) numbers, and CFUs in the spleen, as well as improved bone marrow histopathology. All together, these results confirmed the enhancement of DS on hematopoiesis.

Current status of granulocyte-macrophage colony-stimulating factor in the immunotherapy of melanoma

In 2012, it was estimated that 9180 people in the United States would die from melanoma and that more than 76,000 new cases would be diagnosed. Surgical resection is effective for early-stage melanoma, but outcomes are poor for patients with advanced disease. Expression of tumor-associated antigens by melanoma cells makes the disease a promising candidate for immunotherapy. The hematopoietic cytokine granulocyte–macrophage colony-stimulating factor (GM-CSF) has a variety of effects on the immune system including activation of T cells and maturation of dendritic cells, as well as an ability to promote humoral and cell-mediated responses. Given its immunobiology, there has been interest in strategies incorporating GM-CSF in the treatment of melanoma. Preclinical studies with GM-CSF have suggested that it has antitumor activity against melanoma and can enhance the activity of anti-melanoma vaccines. Numerous clinical studies have evaluated recombinant GM-CSF as a monotherapy, as adjuvant with or without cancer vaccines, or in combination with chemotherapy. Although there have been suggestions of clinical benefit in some studies, results have been inconsistent. More recently, novel approaches incorporating GM-CSF in the treatment of melanoma have been evaluated. These have included oncolytic immunotherapy with the GM-CSF–expressing engineered herpes simplex virus talimogene laherparepvec and administration of GM-CSF in combination with ipilimumab, both of which have improved patient outcomes in phase 3 studies. This review describes the diverse body of preclinical and clinical evidence regarding use of GM-CSF in the treatment of melanoma.

Protective effect of dammarane sapogenins against chemotherapy-induced myelosuppression in mice

Chemotherapy is the most common way to treat malignancies, but myelosuppression, one of its common side-effects, is a formidable problem. The present study described the protective role of dammarane sapogenins (DS), an active fraction from oriental ginseng, on myelosuppression induced by cyclophosphamide (CP) in mice. DS was orally administered at different dosages (37.5, 75, and 150 mg/kg) for 10 d after CP administration (200 mg/kg intraperitoneally). The results showed that DS increased the number of white blood cells (WBC) on day 3 and day 7 (P < 0.05), such that WBC levels were increased by 105.7 ± 29.5% at 75 mg/kg of DS on day 3 (P < 0.05, compared with the CP group). Similar results were observed in red blood cells and platelets in DS-treated groups. The colony-forming assay demonstrated that the depressed numbers of CFU-GM (colony-forming unit-granulocyte and macrophage), CFU-E (colony-forming unit-erythroid), BFU-E (burst-forming unit-erythroid), CFU-Meg (colony-forming unit-megakaryocyte) and CFU-GEMM (colony-forming unit-granulocyte, -erythrocyte, -monocyte and -megakaryocyte) induced by CP were significantly reversed after DS treatment. Moreover, the ameliorative effect of DS on myelosuppression was also observed in the femur by hematoxylin/eosin staining. In DS-treated groups, ConA-induced splenocyte proliferation was enhanced significantly at all the doses (37.5, 75, 150 mg/kg) on day 3 at the rate of 50.3 ± 8.0%, 77.6 ± 8.5% and 44.5 ± 8.4%, respectively, while lipopolysaccharide-induced proliferation was increased mainly on day 7 (P < 0.01), with an increased rate of 39.8 ± 5.6%, 34.9 ± 6.6% and 38.3 ± 7.3%, respectively. The thymus index was also markedly increased by 70.4% and 36.6% at 75 mg/kg on days 3 and 7, respectively, as compared with the CP group. In summary, DS has a protective function against CP-induced myelosuppression. Its mechanism might be related to stimulating hematopoiesis recovery, as well as enhancing the immunological function.

Angiogenesis and progression in human melanoma

In tumor growth, angiogenesis, the process of new-formation of blood vessels from pre-existing ones, is uncontrolled and unlimited in time. The vascular phase is characterized by the new-formation of vascular channels that enhances tumor cell proliferation, local invasion and hematogenous metastasis. Human malignant melanoma is a highly metastatic tumor with poor prognosis, and high resistance to treatment. Parallel with progression, melanoma acquires a rich vascular network, whereas an increasing number of tumor cells express the laminin receptor, which enables their adhesion to the vascular wall, favouring tumor cell extravasation and metastases. Melanoma neovascularization has been correlated with poor prognosis, overall survival, ulceration and increased rate of relapse. Secretion of various angiogenic cytokines, i.e. VEGF-A, FGF-2, PGF-1 and -2, IL-8, and TGF-1 by melanoma cells promote the angiogenic switch and has been correlated to transition from the radial to the vertical growth phase, and to the metastatic phase. Moreover, melanoma cells overexpress alphavbeta3, alphavbeta5, alpha2beta1 and alpha5beta1 integrins and release, together with stromal cells, higher amount of metalloproteases that increasing their invasive potential and angiogenesis. Basing on these observations, different molecular targets of antiangiogenic molecules has be recognized and various antiangiogenic agents are currently in preclinical and clinical trials for melanoma.