Potential identity of multi-potential cancer stem-like subpopulation after radiation of cultured brain glioma

The radio-resistant cancer cell subpopulations of GBM abundantly express CD133, CD117, CD71, and CD45 surface markers, and these radio-resistant cancer cell subpopulations have the capacity for extensive proliferation, self-renewal, and pluripotency. These radio-resistant cancer subpopulations have been shown to initiate tumorigenesis when transplanted into SCID mouse brains. Moreover, these tumors evidenced highly peculiar nest-like shapes harboring both vascular and cancerous tissue structures, which expressed the blood vessel specific marker, the von Willebrand factor. Accordingly, subpopulations of radio-resistant cells in GBM have been shown to be very similar to hematopoietic stem cells (HSCs) in the circulating blood. This similarity may contribute to increased tumor growth and GBM recurrence.The results of the present study provide further evidence for radio resistant subpopulations of cancer stem cells in GBM. Also, our results will assist in the identification and characterization of cancer stem cell populations in glioma, and will help to improve the therapeutic outcomes of GBM.In the past few years, it has been reported that cancers tend to harbor small cell populations with the capability to sustain tumor formation and growth in tumor cells. These cells are referred to as cancer stem cells (CSCs) [1,2]. CSCs have been identified in leukemia [3], multiple myeloma [4] and breast cancer [5,6]. Recently, several studies have demonstrated the existence of CSCs in human brain tumors [7-9]. These CSCs shared many properties, including self-renewal and multi-potency, with normal stem cells [10,11], and expressed a wide variety of transporters involved in drug efflux [12-14]. Moreover, CSCs can initiate tumors when transplanted into immune-deficient mice [10,11].As compared with other brain tumors, glioblastoma multiforme (GBM) is a relatively aggressive variant in humans [15]. A combination of surgery, radiotherapy, and chemotherapy comprises the standard treat