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Objective: To explore the molecular mechanism of resistance to rituximab in diffuse large B-cell lymphoma (DLBCL) during treatment with R-CHOP (rituximab+cyclophosphamide+ doxorubicin+vincristine+prednisone). Methods: FCM was used to detect the expression level of CD20 and the three membrane complement regulatory proteins CD46, CD55 and CD59 in parental cells LY8 [germinal center B-cell-like (GCB) subtype] and NU-DUL-1 [activated B-cell-like (ABC) subtype], rituximab (R) resistance cells LY8-R and NU-DUL-1-R, chemotherapy drug cyclophosphamide+doxorubicin+ vincristine (CHO) resistance cells LY8-CHO and NU-DUL-1-CHO, and rituximab combined with CHO resistance (RCHO) LY8-RCHO and NU-DUL-1-RCHO cells. The expression level of CD20 protein and mRNA were detected by Western blotting and real-time fluorescent quantitative PCR, respectively. The expression levels of CD20, CD46, CD55 and CD59 in SRY (sex determining region Y)-box 2 (SOX2) overexpression of parental LY8 and NU-DUL-1 cells as well as SOX2 gene silencing of LY8-RCHO and NU-DUL-1-RCHO cells were detected by FCM method. Furthermore, in tumor tissues of clinical 25 DLBCL patients with at least 6 circles of R-CHOP regimen treatment, immunohistochemical were used to detect the expression levels of CD20 and SOX2 before and after the treatment. Results: Compared with the parental cells, in the LY8-R, LY8-RCHO and NU-DUL-1-R and NU-DUL-1-RCHO cells that developed rituximab resistance, not in LY8-CHO and NU-DUL-1-CHO cells which resistant to chemotherapy, the expression level of CD20 was significantly reduced (all P < 0.001), while the expression levels of CD46, CD55 and CD59 were also decreased (all P < 0.05). The expression level of CD20 protein and mRNA were significantly reduced (P < 0.001and P < 0.01). Furthermore, in the parental LY8 and NU-DUL-1 cells, overexpression of SOX2 significantly reduced the expression level of CD20 (P < 0.000 1), while knockdown of SOX2 in LY8-RCHO and NU-DUL-1-RCHO cells significantly increased the expression level of CD20 (P < 0.0001). It was further found that the expression level of CD20 in tumor tissues of DLBCL patients was significantly decreased after R-CHOP treatments (P < 0.01), and the expression level of SOX2 was significantly increased (P < 0.001). After comprehensive analysis, it was found that there was a negative correlation between CD20 and SOX2 expression in tumor tissues (P < 0.000 1). Conclusion: SOX2 induces DLBCL resistance to rituximab by reducing the expression level of CD20.
ABSTRACT
ABSTARCT:Objective To investigate the effects of the transcription factor SRY-related high-mobility-group box 2 (Sox2)related to stem cells on the invasion and migration of cervical squamous carcinoma cell line SiHa and its mechanism.Methods The expression of Sox2 was detected in Sox2 stably over-expressed cell line SiHa-Sox2 and negative control SiHa-EGFP cells by RT-PCR and Western blotting,respectively.The effects of Sox2 on the invasion and migration capacities of SiHa cells were detected by wound-healing assay and transwell assay.The expression of β-catenin was detected by Western blot.Results Compared with that of SiHa-EGFP cells,the expression of Sox2 at both mRNA and protein levels was obviously upregulated in SiHa-Sox2 cells.The migration and invasion capacities of SiHa-Sox2 cells were increased significantly (P <0.01 ),and the expression of β-catenin increased dramatically compared with that of the control cells.Conclusion Sox2 promotes the invasion and migration capacities of SiHa cells by increasing the expression of β-catenin and activating Wnt signaling pathway, which contributes to the development of cervical cancer.
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Objective To study the diagnostic value of Sox2 mRNA transcription level in bronchoscopic biopsy specimens from lung cancer patients. Methods The expression of Sox2 mRNA was detected using RT-PCR from 100 hu-man lung cancer biopsy and 18 non-cancer lung biopsy through bronchoscopy. The expression of Sox2 protein was examined by immunohistochemistry from 50 cases of lung cancer biopsy, 32 cases of benign lung lesions and 18 cases of pericarcino-matous normal lung tissues. Then the relationships between Sox2 mRNA transcription level and lung cancer clinical patho-logical parameters were analyzed to test the diagnostic value of Sox2 transcription level. Results The transcription of Sox2 mRNA and its protein expression level were significantly higher in lung cancer than that in benign pulmonary disease tissues (P＜0.05). The transcription of Sox2 mRNA was not correlated with age, gender, histology, lymph node metastasis, TNM stage and differentiation of lung cancer patients (P>0.05). The Sox2 mRNA yielded an area of 0.748 under the ROC curve with the sensitivity of 85.0%and the specificity of 61.1%, taking the cut-off value of 0.513. Conclusion The Sox2 mRNA might be a useful diagnostic marker for lung cancer.
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Immunohistochemistry examination showed that SOX-2 was expressed in all 23 cases of odontogenic cyst and in 2 cases of poly-cystic ameloblastoma.