Effects of CDC7 gene silencing and Rituximab on apoptosis in diffuse large B cell lymphoma cells.
BACKGROUND
The cell division cycle 7 (CDC7) is a serine-threonine kinase, which is required for DNA replication and is high expressed in diffuse large B cell lymphoma (DLBCL).


METHODS
In this study, we targeted CDC7 in human DLBCL-ABC subtype cells (ly3) and examined the subsequent alterations in cellular apoptosis. The expression of CDC7 was silenced with small interfering RNA (siRNA)-expressing plasmid. CDC7 gene silencing cells were then incubated with or without rituximab for 24 h. Following treatment, Annexin V/propidium iodide staining followed by flow cytometry was used to examine cellular apoptosis. Furthermore, the expression of caspase 3, Bax, and Bcl-2 protein was analyzed by Western blotting. The expression of Bax and Bcl-2 mRNA was analyzed by quantitative real-time PCR.


RESULTS
Compared to non-treated or control siRNA-transfected cells, significantly higher levels of apoptosis were detected in siCDC7-transfected cells and rituximab-treated cells (P < 0.05), which was further enhanced in CDC7-targeted cells with rituximab treatment (P < 0.05). The pro-apoptotic effects were accompanied with up-regulation of caspase 3 and Bax, meanwhile down-regulation of Bcl-2.


CONCLUSIONS
Combined treatments using rituximab and CDC7 gene silencing significantly increases apoptosis in ly3 cells and plays synergistic effect. CDC7 is a novel therapeutic target in DLBCL patients. CDC7 inhibitors combined with rituximab will be the new therapy for the ABC-DLBCL patients.
Lymphoma Department, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China. houyunoncology@163.com
Yun
Y
Hou
Hua-Qing
HQ
Wang
Yi
Y
Ba
D058846:Antibodies, Monoclonal, Murine-Derived / Q000494:pharmacology*; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000235:genetics*; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D045744:Cell Line, Tumor; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics; D020868:Gene Silencing; D006801:Humans; D016403:Lymphoma, Large B-Cell, Diffuse / Q000188:drug therapy* / Q000235:genetics* / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D000069283:Rituximab; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics; D051028:bcl-2-Associated X Protein / Q000235:genetics / Q000378:metabolism
D058846:Antibodies, Monoclonal, Murine-Derived; D000970:Antineoplastic Agents; D018797:Cell Cycle Proteins; D012333:RNA, Messenger; D051028:bcl-2-Associated X Protein; D000069283:Rituximab; C068619:CDC7 protein, human; D017346:Protein Serine-Threonine Kinases; D053148:Caspase 3