Antiproliferative and Antiangiogenic Effects of Punica granatum Juice (PGJ) in Multiple Myeloma (MM).

Multiple myeloma (MM) is a clonal B-cell malignancy characterized by an accumulation of clonal plasma cells (PC) in the bone marrow (BM) leading to bone destruction and BM failure. Despite recent advances in pharmacological therapy, MM remains a largely incurable pathology. Therefore, novel effective and less toxic agents are urgently necessary. In the last few years, pomegranate has been studied for its potential therapeutic properties including treatment and prevention of cancer. Pomegranate juice (PGJ) contains a number of potential active compounds including organic acids, vitamins, sugars, and phenolic components that are all responsible of the pro-apoptotic effects observed in tumor cell line. The aim of present investigation is to assess the antiproliferative and antiangiogenic potential of the PGJ in human multiple myeloma cell lines. Our data demonstrate the anti-proliferative potential of PGJ in MM cells; its ability to induce G0/G1 cell cycle block and its anti-angiogenic effects. Interestingly, sequential combination of bortezomib/PGJ improved the cytotoxic effect of the proteosome inhibitor. We investigated the effect of PGJ on angiogenesis and cell migration/invasion. Interestingly, we observed an inhibitory effect on the tube formation, microvessel outgrowth aorting ring and decreased cell migration and invasion as showed by wound-healing and transwell assays, respectively. Analysis of angiogenic genes expression in endothelial cells confirmed the anti-angiogenic properties of pomegranate. Therefore, PGJ administration could represent a good tool in order to identify novel therapeutic strategies for MM treatment, exploiting its anti-proliferative and anti-angiogenic effects. Finally, the present research supports the evidence that PGJ could play a key role of a future therapeutic approach for treatment of MM in order to optimize the pharmacological effect of bortezomib, especially as adjuvant after treatment.

Wogonin inhibits multiple myeloma-stimulated angiogenesis via c-Myc/VHL/HIF-1α signaling axis.

Angiogenesis is associated with the progression of multiple myeloma (MM). Wogonin is an active mono-flavonoid with remarkable antitumor activity. However, its impact on MM-stimulated angiogenesis remains largely unknown. Here, we demonstrated that wogonin decreased expression and secretion of pro-angiogenic factors in MM cells via c-Myc/HIF-1α signaling axis, reducing MM-stimulated angiogenesis and MM cell proliferation in vivo. Overexpression of c-Myc in MM cells disrupted the balance between VHL SUMOylation and ubiquitination, and thus inhibited proteasome-mediated HIF-1α degradation. Impaired function of VHL ubiquitination complex in c-Myc-overexpressing cells was fully reversed by wogonin treatment via increasing HIF-1α-VHL interaction and promoting HIF-1α degradation. Collectively, our in vitro and in vivo studies reveal for the first time that wogonin represses MM-stimulated angiogenesis and tumor progression via c-Myc/VHL/HIF-1α signaling axis.

Antiangiogenic therapeutic approaches in multiple myeloma.

Angiogenesis is a constant hallmark of multiple myeloma (MM) progression and has prognostic potential. The pathophysiology of MM-induced angiogenesis involves both direct production of angiogenic cytokines by plasma cells and their induction within the bone marrow microenvironment. An improved understanding of the importance of angiogenesis-related signaling in MM has allowed for the rational use of antiangiogenic therapies in this tumor. This review article summarizes the literature data concerning the employment of the most important antiangiogenic therapeutic agents actually used in preclinical models and clinical settings for the treatment of MM.

Emerging therapies targeting tumor vasculature in multiple myeloma and other hematologic and solid malignancies.

Research on the formation of new blood vessels (angiogenesis) in general and vascular endothelial growth factor (VEGF) in particular is a major focus in biomedicine and has led to the clinical approval of the monoclonal anti- VEGF antibody bevazicumab; and the second-generation multitargeted receptor kinase inhibitors (RTKIs) sorafenib, sunitinib, and pazopanib. Although these agents show significant preclinical and clinical anti-cancer activity, they prolong overall survival of cancer patients for only months, followed by a restoration of tumor growth and progression. Therefore, there is a clear need to increase our understanding of tumor angiogenesis and the development of resistance. In this review we discuss up-to-date knowledge on mechanisms of tumor angiogenesis, and summarize preclinical and clinical data on existing and potential future anti-angiogenic agents and treatment strategies for Multiple Myeloma (MM) and other hematologic and solid malignancies.

Perineural angiogenesis in mice bearing subcutaneous tumours.

Cells of myeloma or fibrosarcoma were inoculated s.c. into BALB/c mice. Intact skins and tissue sections from animals killed at periodic intervals after inoculation of tumor cells were examined macroscopically and microscopically. The development of new blood vessels, probably involved in vascularization of the tumor, was observed around the nerves adjacent to the deposit of tumour cells. This occurred 5 days after inoculation of cells and before the tumour had a mean diameter of less than 1 mm. Lesser degrees of "perineural angiogenesis" were noted after s.c. inoculation of mineral oil, Freund's complete adjuvant or implantation of intact spleen, but none was observed with killed tumour cells.