Real-time detection of LMP1/LMP1 interaction in MβCD-induced apoptosis of nasopharyngeal carcinoma cells using FRET method

Latent mermbrane protein 1(LMP1)is known as an oncoprotein in nasopharyngeal carcinoma(NPC)cells,which is considered to have a strong association with growth,invasion and metastasis of NPC cells through lipid rafts.Met hy-A-cyclodextrin(M3CD)can disrupt lipid rafts through cholesterol depletion.In this study,we revealed that MICD induced apoptosis in two kinds of NPC cells including CNE1 cells,a LMP1 negative nasopharyngeal squamous carcinoma cell line,and CNE1-LMP1 cells,a LMP1-positive nasopharyngeal squamous carcinoma cell line.Furthermore,the impact of MBCD on LMP1 was investigated by fuorescence resonance energy transfer(FRET)method in NPC cells.Synchronized tempo spatial and spectral detection of LMP1/LMP1 interaction were performed using fluorescence microscope and spectrograph.FRET efficiency indicated that LMP1/LMP1 interaction gradully enhanced after M9CD treatment.MTT assays showed that M8CD caused strong cytotoxicity in CNE1 cells,but cauused relatively weaker cytotoxicity in CNE1-LMP1 cells,which indicated that LMP1 may regulate sensitivity of NPC cells to MBCD.Then,detection of cleaved caspase-3 in two kinds of NPC cells indicated that LMP1 may inhibit activation of caspase 3.These results strongly suggested that MBCD can induce apoptosis of NPC cells,but enhancing of LMP1/LMP1 interaction may likely resist apoptosis through inhibiting cleavage of caspase-3.