Antitumor Activity of Bioactive Compounds from Rapana venosa against Human Breast Cell Lines.

This study is the first report describing the promising antitumor activity of biologically active compounds isolated from the hemolymph of marine snail Rapana venosa-a fraction with Mw between 50 and 100 kDa and two structural subunits (RvH1 and RvH2), tested on a panel of human breast cell lines-six lines of different molecular subtypes of breast cancer MDA-MB-231, MDA-MB-468, BT-474, BT-549, SK-BR-3, and MCF-7 and the non-cancerous MCF-10A. The fraction with Mw 50-100 kDa (HRv 50-100) showed good antitumor activity manifested by a significant decrease in cell viability, altered morphology, autophagy, and p53 activation in treated cancer cells. An apparent synergistic effect was observed for the combination of HRv 50-100 with cis-platin for all tested cell lines. The combination of HRv 50-100 with cisplatin and/or tamoxifen is three times more effective compared to treatment with classical chemotherapeutics alone. The main proteins in the active fraction, with Mw at ~50 kDa, ~65 kDa, ~100 kDa, were identified by MALDI-MS, MS/MS analyses, and bioinformatics. Homology was established with known proteins with antitumor potential detected in different mollusc species: peroxidase-like protein, glycoproteins Aplysianin A, L-amino acid oxidase (LAAO), and the functional unit with Mw 50 kDa of RvH. Our study reveals new perspectives for application of HRv 50-100 as an antitumor agent used alone or as a booster in combination with different chemotherapies.

Cationic (Co)polymers Based on N-Substituted Polyacrylamides as Carriers of Bio-macromolecules: Polyplexes, Micelleplexes, and Spherical Nucleic Acidlike Structures.

Novel N-substituted polyacrylamides bearing a cycle with two tertiary amines, poly(4-methyl-piperazin-1-yl)-propenone (PMPP) and its block copolymers with polylactide (PMPP-b-PLA), are synthesized and characterized. The homopolymers are water-soluble, whereas the block copolymers self-assemble in aqueous solution into a small size (Rh around 30 nm), are narrowly distributed, and exhibit core-shell micelles with good colloidal stability. Both the homopolymers and copolymer micelles are positively charged (ζ-potentials in the 13.8-17.6 mV range), which are employed for formation of electrostatic complexes with oppositely charged DNA. Complexes (polyplexes, micelleplexes, and spherical nucleic acidlike structures) in a wide range of N/P (amino to phosphate groups) ratios are prepared with short (115 bp) and long (2000 bp) DNA. The behavior and physicochemical properties of the resulting nanocarriers of DNA are strongly dependent on the polymer/polymer micelles' characteristics and the DNA chain length. All systems exhibit low cytotoxicity and good cellular uptake ability and show promise for gene delivery and regulation.

The Effect of a Ferrocene Containing Camphor Sulfonamide DK-164 on Breast Cancer Cell Lines.

BACKGROUND: Drug resistance is a major cause of cancer treatment failure. Most cancer therapies involve multiple agents, to overcome it. Compounds that exhibit strong anti-tumor effect without damaging normal cells are more and more in the focus of research. Chemotherapeutic drugs, combining different moieties and functional groups in one molecule, can modulate different regulatory pathways in the cell and thus reach the higher efficacy than the agents, which affect only one cellular process. METHODS: We tested the effect of recently synthesized ferrocene-containing camphor sulfonamide DK-164 on two breast cancer and one breast non-cancer cell lines. The cytotoxic effects were evaluated using the standard MTT-dye reduction and clonogenic assays. The apoptotic or autophagic effects were evaluated by Annexin v binding or LC3 puncta formation assays, respectively. Cell cycle arrest was determined using flow cytometry. Western blot and immunofluorescent analyses were used to estimate the localization and cellular distribution of key regulatory factors NFκB and p53. RESULTS: Compound DK-164 has well pronounced cytotoxicity greater to cancer cells (MDA-MB-231 and MCF-7) compared to non-cancerous (MCF-10A). The IC50 value of the substance caused a cell cycle arrest in G1 phase and induced apoptosis up to 24 hours in both tumor cells, although being more pronounced in MCF-7, a functional p53 cell line. Treatment with IC50 concentration of the compound provoked autophagy in both tumor lines but is better pronounced in the more aggressive cancer line (MDA-MB-231). CONCLUSION: The tested compound DK-164 showed promising properties as a potential therapeutic agent.

High mobility group B1 protein interacts with its receptor RAGE in tumor cells but not in normal tissues.

The high mobility group box 1 (HMGB1) protein is an abundant non-histone component of chromatin well known for its two DNA binding domains, HMG box A and HMG box B. The main characteristics of the HMGB1 protein as an 'architectural' factor are its ability to recognize and bind with high affinity to distorted DNA and its ability to induce kinks in linear DNA fragments. The HMGB1 protein has been correlated to cancer progression. An elevated expression of HMGB1 occurred in certain types of primary tumor, including melanoma and colon, prostate, pancreatic and breast cancers, and in the majority of cases HMGB1 is associated with invasion and metastasis. The main signaling pathway is activated through the interaction of HMGB1 with its Receptor for Advanced Glycation End products (RAGE). Certain data indicate that an elevated expression of RAGE and HMGB1 is not always a prerequisite of poor prognosis of tumor development. The cellular localization of the ligand/receptor pair also requires consideration. The data concerning the expression of HMGB1 protein and its receptor RAGE in various tissues and tumor cells reflect the overall production of the proteins. However, they do not refer to their cellular localization and there is no direct evidence for the formation of a stable complex between them. In the present study, we investigated the subcellular distribution of HMGB1 and its receptor RAGE in various rat organs compared to Guerin ascites tumor cells. In the normal tissues the proteins exist in their soluble form, whereas in the tumor cells they are insoluble and membrane-bound. HMGB1 forms a stable complex with RAGE only in the protein extract derived from the cancer cells predominantly in the membrane fraction.

Mismatch repair-driven mutational bias in D. melanogaster.

We have used microsatellite sequences to evaluate the influence of the mismatch repair system on mutation bias in D. melanogaster. While mismatch-proficient cells have the highest mutation rate at (GT)(n) repeats, (AT)(n) repeats were the least stable ones in spel1(-/-) flies lacking functional mismatch repair. Furthermore, the mutation spectrum of long microsatellite alleles in spel1(-/-) was slightly upward biased, resulting in a gain of repeats, whereas wild-type flies have a strong downward bias. Interestingly, this mismatch repair-mediated downward mutation bias is reflected in the genome composition of D. melanogaster. When compared to other species, D. melanogaster has significantly shorter microsatellites. Our results suggest that the mismatch repair system may have an important role in shaping genome composition.