Targeting PIWIL2-like (PL2L) proteins by a monoclonal antibody for immunotherapy of both solid and hematopoietic cancers.

e14001Background: Broad spectrum immunotherapeutic target is critical but has encountered a bottle-neck for immunotherapy to cure cancers. We have previously reported that the PIWIL2-like (PL2L) protein 60, a product of alienation-activated PIWIL2 gene, is widely expressed in various types of hematopoietic and solid tumors and mediates tumorigenesis. However, it is unknown whether PL2L60 is an efficient broad spectrum target for cancer immunotherapy. Methods: PL2L-specific monoclonal antibody (mAb: KAO3) was used to pretreat various types of tumor cell lines from human or mouse before inoculation or treat the established tumors from the same lines, including lymphoma, melanoma, breast cancer, lung cancer and cervical cancer. The machanisms underlying mAb KAO3 inhibiting tumorigenesis were explored using the parameters of cell cycle, cell proliferation, apoptosis and complement-dependent cytotoxicity. The KAO3+ tumor cells were isolated to compare KAO3- cells in tumorigenesis of various tumor cell types of...