Specific Seaweed Extract Induce Apoptosis in Non-Hodgkin's Lymphoma.

Abstract 4810

Diffuse large B-cell lymphoma (DLBCL) is a common subtype of aggressive non-Hodgkin lymphoma derived from germinal center (GC) and (post-) non-GC B-cells based on gene expression studies. Differences in five-year survival rates between these subtypes may be clinically relevant with enhanced survival for GC versus non-GC DLBCL. Although the adoption of R-CHOP as the new standard of care has led to improved outcomes, new treatment modalities are still needed. Seaweed derived galactofucan sulfate is already being widely used as a complimentary medicine by cancer patients. The medical community commonly criticizes the efficacy of naturopathic medicines, as they have not undergone evaluation in an accepted scientific manner. In an on going clinical trial we attempt to evaluate seaweed extracts with respect to its tolerability, safety and activity in cancer patients. In phase-I patients showed no toxicity for seaweed extract (TSE01) and the maximum dose was limited by patients' tolerability to take a number of capsules daily. In phase-II all patients received the 10gm/day of TSE01 or the maximum tolerated dosage observed from Phase-I. We found that a seaweed extract (TSE01) had anti-tumorigenic effects. At the same time different leukemia and lymphoma cell lines were treated with varying concentrations of seaweed extracts that were prepared in house. Cellular viability using the trypan blue exclusion assay, and apoptosis and necrosis using flow cytometric analysis (annexin V apoptosis assay) were studied in four different cell lines; OCI-LY-19, KG1, RL, and WSU-DLCL2. MTT assay was also used to measure the activity of living cells via mitochondrial dehydrogenase activity. RNA was isolated from all cell lines for further analysis. Any concentration of seaweed extract (CSE01) above 5.2 mM was found toxic to all cell lines. CSE01 used at 2.6 mM had an inhibitory effect on the growth of a non-GC DLBCL cell-line, OCI-LY-19, while having no effect on other non-lymphoma or leukemia cell lines. At this specific concentration, we monitored the expression of a panel of pathway or disease-specific genes using the RT2 profiler PCR array system. The human apoptosis pathway-finder PCR array profiles the expression of 84 key genes involved in apoptosis, or programmed cell death. The array includes the TNF ligands and their receptors; members of the bcl-2, caspase, IAP, TRAF, CARD, death domain, death effector domain, and CIDE families; as well as genes involved in the p53 and ATM pathways. After treatment with CSE01, only one cell line (OCI-LY-19) showed changes in the expression of 3 genes (FASLG, BIRC3, TNFRSF1A). A fold-up regulation of 4.4 in the BIRC3 was observed and fold-down regulation of -2.8 and -2088 in TNFRSF1A and FASLG was observed, subsequently. Down regulation of FASLG gene, a TNF ligand family member plays an important role in the apoptosis-induction through mitochondrial pathway of OCI-LY-19 cell line. Given the less favorable response to standard therapies for non-GC DLBCL, investigational approaches using new agents such as CSE01 may eventually improve treatment of these types of lymphoma.