Saumen Karan

Poly-L-Lysine Inhibits Tumor Angiogenesis and Induces Apoptosis in Ehrlich Ascites Carcinoma and in Sarcoma S-180 Tumor

Background: This study focuses on the role of Poly-L-lysine (PLL), an essential amino acid, on molecular changes of tumor angiogenesis suppression, pro-apoptotic and anti-apoptotic gene expression after treatment on Ehrlich ascites carcinoma (EAC) and solid sarcoma-180 tumor cells bearing mice. Materials and Methods: The cell viability was carried out using MTT assay. The antitumor activity was evaluated by treatment with PLL at 20 and 40mg/kg/b.w doses for 14 days in EAC ascites tumor and 21 days for Sarcoma-180 solid tumor model. Several tumor evaluation studies, haematological and biochemical parameters were estimated. Importantly, the tumor cell apoptosis was assessed using microscopic observations, DNA fragmentation assay, Flow cytometric analysis, cell-cycle and electron-microscopic study, following which, the expression of several signal proteins related to pro-apoptosis, anti-apoptosis and tumor angiogenesis were quantified using western blotting and immunohistochemistry study. Results: Precisely, PLL had cytotoxic effect on K562; A549; U937 and B16F10 cancer cells. Significant decreases in liquid and solid tumors and increased life span of treated mice were observed (P<0.05). Typical morphological changes, apoptosis bleb phenomenon and sub-G1 cell cycle arrests revealed that PLL promoted apoptotic cell death. Western blot and immunohistochemistry confirms, PLL activated apoptotic signalling cascades through down regulation of Bcl-2 and CD31 protein and up-regulation of Bax and p53 proteins. The anti-angiogenic effects were also accompanied with decreased VEGF expression and reduced peritoneal-angiogenesis and microvessel density. Conclusions: The antitumor and antitumor-angiogenic activity of PLL was confirmed from all the results via up and down regulation of relevant signal proteins reported in this publication.

Induction of apoptosis, anti-proliferation, tumor-angiogenic suppression and down-regulation of Dalton’s Ascitic Lymphoma (DAL) induced tumorigenesis by poly-l-lysine: A mechanistic study

PURPOSE The present study, attempts to validate the molecular mechanism(s) of Poly-l-lysine (PLL) induced apoptosis, anti-proliferative and anti-tumorigenic properties in in-vitro HUVECs cells and Daltons Ascitic Lymphoma (DAL) and in in-vivo DAL cell bearing BALB/c mice model. MATERIALS AND METHODS The cell proliferation assay and morphological assay was carried out using the MTT assay and Giemsa staining method. The antitumor activity of PLL was evaluated in BALB/c mice at 20 and 40 mg/kg/b.w doses for 21 days for DAL solid tumor model. Several tumor evaluation endpoints, hematological and biochemical parameters were estimated. Additionally, the tumor apoptosis, anti-proliferative and anti-tumor angiogenesis effects were assessed using western blots and immunohistochemistry. RESULTS PLL significantly decreased cell proliferation in in-vitro HUVECs and DAL cells without significant effects on normal cell growth. PLL also induced alteration in cellular morphology in DAL cells. Therafter, in the BALB/c mouse model, PLL had noticeable inhibition in DAL-induced tumorigenesis. This inhibition was evident through reduced solid tumor volume and weight versus the control group. However, PLL promoted tumor apoptosis and suppressed cell-proliferation and tumor-angiogenesis. PLL also increased hematological markers significantly compared to 5-flurouracil (5-FU). The amount of TdT in the nuclei of DAL cells in mice treated with PLL was significantly increased while in contrast decreases of anti-apoptotic protein Bcl-2 expression were observed. PLL also significantly upregulated the pro-apoptotic protein Bax and activated caspase-3. Measurable decreases of cyclin-D1 were observed through PLL treatments, an indicator of cell-cycle arrest. These studies also indicate PLLs induction and anti-proliferative effects through suppression of the c-Myc and Ki-67 proliferation-indices. Additionally, PLL inhibited tumor-angiogenesis through suppression of VEGF and CD34 protein expression levels and reduction ofmicrovesseldensityversus similar parameters in tumors from control mice. CONCLUSION The present study offers opportunities and hopes for possible anti-tumortherapies with PLL in the near future and warrants further formulation developments.