erucylphospho-n-n-n-trimethylpropylammonium and Bone-Neoplasms

High osteopontin (OPN) expression is linked to breast cancer bone metastasis. In this study we modulated osteopontin levels conditionally and investigated any related antineoplastic effects. Therefore, we established cell clones from human breast cancer MDA-MB-231 cells, in which the expression of OPN is regulated by the Tet-Off tet-off system. These cells, which conditionally express a specific miRNA targeting OPN, were used for in vitro studies as well as for a bone metastasis model in nude rats. Changes in whole-genome expression elicited by conditional OPN knockdown and vesicle formation were also analyzed. The alkylphosphocholine erufosine was used for combination therapy. Conditional OPN knockdown caused mild anti-proliferative, but more intensive anti-migratory and anti clonogenic effects, as well as partial and complete remissions of soft tissue and osteolytic lesions. These effects were associated with specific gene and protein expression modulations following miRNA-mediated OPN knockdown. Furthermore, high levels of OPN were detected in vesicles derived from rats harboring breast cancer skeletal metastases. Finally, the combination of OPN inhibition and erufosine treatment caused an additive reduction of OPN levels in the investigated breast cancer cells. Thus, knockdown of OPN alone or in combination with erufosine is a promising strategy in breast cancer skeletal metastasis treatment.

Topics: Animals; Antineoplastic Agents; Bone Neoplasms; Breast Neoplasms; Cell Line, Tumor; Cell Movement; Cell Proliferation; Female; Gene Knockdown Techniques; Humans; Male; Organophosphates; Osteopontin; Quaternary Ammonium Compounds; Rats; Rats, Nude; RNAi Therapeutics

MDA-MB-231 human breast cancer cells transfected with GFP were used as model to determine the reduction in proliferation, colony formation, and migration in response to agents with anti-metastatic properties. These agents consisted of antisense oligonucleotides (ASOs) directed against osteopontin (OPN), bone sialoprotein II (BSP II), and osteonectin (ON), as well as an antibody directed against BSP II. A bisphosphonate derivative (ibandronate) and an alkylphosphocholine (erucylphospho-NNN-trimethylpropanolamine; ErPC3) were used as positive controls. The ASOs directed against OPN, BSP II and ON suppressed the expression of their respective target proteins by 81%, 74% and 69%, respectively. They were barely but significantly active in inhibiting the proliferation, but intermediately to highly active in inhibiting the colony formation and migration of GFP-MDA-MB-231 breast cancer cells. The antibody against human BSP II was significantly more active than all ASOs used and was equally active or even surpassed the activity of ibandronate and ErPC3 in all three assays. The results obtained suggest a specific anti-metastatic activity of this antibody as well as of the ASOs found effective in decreasing OPN and BSP II expression.

Topics: Adult; Bone Neoplasms; Breast Neoplasms; Cell Division; Cell Movement; Child; Colony-Forming Units Assay; Diphosphonates; Down-Regulation; Female; Green Fluorescent Proteins; Humans; Ibandronic Acid; Immunoglobulin G; Integrin-Binding Sialoprotein; Luminescent Proteins; Male; Oligonucleotides, Antisense; Organophosphates; Osteoblasts; Osteopontin; Osteosarcoma; Quaternary Ammonium Compounds; Sialoglycoproteins