Inhibition of nucleo-cytoplasmic shuttling through XPO1/CRM1: a unique therapeutic approach for treatment of haematological and solid malignancies

Cancer is one of the leading cause of morbidity and mortality worldwide. Regulated nucleo-cytoplasmic shuttling is very crucial for maintaining cellular homeostasis. Emerging evidence suggests that deregulation of the nucleo-cytoplasmic transport results in abnormal cell growth, cell cycle, apoptosis, tumor progression and drug resistance. Exportin-1 (also called as chromosome region maintenance 1) belongs to karyopherin-β superfamily and is the main mediator of nuclear export in several cell types. The XPO1 / CRM1 protein is overexpressed in liposarcoma, Ewing sarcoma, ovarian carcinoma, pancreatic cancer, hepatocellular carcinoma, lung carcinoma, osteosarcoma, gastric carcinoma, melanoma, glioma, acute myeloid leukemia, acute lymphocytic leukemia, chronic myeloid/lymphoid leukemia as well as multiple myeloma. Hot spot mutations were observed in many cancers. Higher levels of XPO1 / CRM1 are associated with poor prognosis, resistance to chemotherapy and recurrence in a large number of human malignancies. There are growing evidence that provided the foundation that inhibition of nuclear export by inhibiting nuclear export receptor ( XPO1 ) might be a potential targeted therapeutic approach for the treatment of human cancers in the clinic. In the present review, we will discuss the role of XPO1 in cancers and potential of selective inhibitors of nuclear export ( XPO1 inhibitors) to restore the normal function of tumor suppressor and growth regulatory proteins by blocking their export. Selinexor (KPT-330) is an orally available, highly potent and is being tested in human phase-I/II clinical trials in both haematological and solid malignancies.