Fighting Cancer Stem Cells Via Armored Mesenchymal Stem Cells with Napabucasin: A New Strategy for Cancer Therapy

Cancer relapse and metastasis are associated with part of cancer cells with stem cell properties. These cancer stem cells are resistant to current treatment of cancer, such as chemotherapy and radiation therapy. Stem cell biologists hypothesized that inhibition of cancer stemness can effectively suppress metastasis and relapse. BBI608 (Napabucasin) is a small molecule which inhibits Stat3 cell signaling pathway and cancer stemness properties. This drug can block spherogenesis of cancer stem cell and kill them effectively. Recently rattle-type nanoparticles that are hollow nanospheres with mesoporous shells and metal cores are introduced for drug delivery. These types of the nanoparticle can effectively entrap small molecules and efficiently anchored to the surface of mesenchymal stem cells by specific antigen-antibody recognitions. Mesenchymal stem cells can track tumors and their micrometastasis after intravenous injection in the cancer animal models. We suggest that mesenchymal stem cells armored with entrapped Napabucasin in silica nanorattle can effectively track tumors and deliver Napabucasin to cancer stem cells to inhibit them and subsequently eradicate the tumor bulk. This protocol combined with current chemotherapeutic drugs can be employed for the treatment of cancer in particular metastatic cancer.