Since then many pathological reports demonstrated that the expression of CSE1L in cancer is related to cancer proliferation [6–10], although there
is no experimental studies to show that increased CSE1L expression in cancer cells can enhance the proliferation of cancer cells. CSE1L is highly expressed in cancer; thus, if CSE1L plays SB202190 concentration a role in cancer cell proliferation during cancer development, increased CSE1L expression in cancer cells should be able to increase the proliferation of cancer cells. Our recent study showed that increased CSE1L expression in MCF-7 human breast cancer cells was unable to stimulate cell proliferation [11]. Increased CSE1L expression was also unable to increase the proliferation of other cancer cells including HT-29 human colorectal cancer cells, Hep G2 human hepatocarcinoma cells, 293 kidney cancer cells, and B16-F10 mouse melanoma cells (unpublished data). The results of our study further showed that CSE1L enhanced the invasion and find more metastasis of B16-F10 cancer cells in animal metastasis studies [11]. CSE1L is a cellular apoptosis susceptibility protein and it is highly expressed in various CHIR98014 clinical trial cancers; our recent studies showed that CSE1L plays an important role in regulating cancer cell apoptosis induced by chemotherapeutic drugs [12, 13]. Therefore, CSE1L may be a target
for developing strategies to improve the efficacy of cancer chemotherapy as well as for screening more potent anticancer reagents. CSE1L in chemotherapeutic drug-induced cancer cell apoptosis Apoptosis (or programmed cell death) plays an important role in mediating apoptotic stimuli including chemotherapeutic drug-induced
cell cytotoxicity [14]. CSE1L is a cellular apoptosis susceptibility protein, and CSE1L-mediated cancer cell apoptosis was first investigated by Brinkmann et al. using a vector expressing antisense CSE1L cDNA. Their results showed that CSE1L mediated apoptosis induced by Pseudomonas exotoxin, diphtheria toxin, and tumor necrosis factor but did not mediate apoptosis induced by ricin, cycloheximide, staurosporine, or etoposide, a cancer chemotherapeutic drug. Therefore, CSE1L-mediated apoptosis was thought to be limited to selected apoptotic stimuli such as adenosine diphosphate (ADP)-ribosylating check details toxins and tumor necrosis factor [3, 15]. CSE1L is essential for cell survival, and severe depletion of CSE1L can cause cell death [16]. Those studies used antisense CSE1L cDNA to reduce the cellular CSE1L level; hence the results of their studies might have been a result of those transfected cells expressing not very low levels of CSE1L. Also, they only tested the cancer chemotherapeutic drug, etoposide. An apoptosis-regulating protein should not only regulate apoptosis induced by just ADP-ribosylating toxins and tumor necrosis factor.