Provided are compositions and methods for treating or ameliorating a cancer by targeting cell surface-expressed ALPHA-V BETA-3 polypeptides in Cancer Stem Cells (CSCs) to kill the CSCs, to treat cancers caused or initiated by cancer or tumor 10 cells, or Cancer Stem Cells (CSCs), expressing ALPHA-V BETA-3 polypeptides on their cell surfaces. Provided are compositions and methods for targeting and killing ALPHA-V BETA-3-positive Cancer Stem Cells (CSCs) and treating drug resistant cancers. In alternative embodiments, compositions and methods as provided herein use an antibody that can specifically bind to human ALPHA-V BETA-3 that also comprises an Fc portion that can mediate antibody-dependent cell-mediated cytotoxicity (ADCC) killing of cancer cells by macrophages； for example, use a humanized antibody to ALPHA-V BETA-3 that has been modified to include an engineered Fc portion that specifically binds to human macrophages.
