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cAMP responsive element binding protein-1 is a transcription factor of lysosomal-associated protein transmembrane-4 Beta in human breast cancer cells.

Zhang M, Xu JJ, Zhou RL, Zhang QY - PLoS ONE (2013)

Bottom Line: Lysosomal-associated protein transmembrane-4 beta (LAPTM4B) is a potential proto-oncogene, whose overexpression is involved in cancer occurrence and progression.However, its transcriptional regulation mechanism is still unclear.The +10+292 promoter region was possessed the highest transcriptional activity.

View Article: PubMed Central - PubMed

Affiliation: Department of Clinical laboratory, Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Cancer Hospital & Institute, Beijing, China.

ABSTRACT
Lysosomal-associated protein transmembrane-4 beta (LAPTM4B) is a potential proto-oncogene, whose overexpression is involved in cancer occurrence and progression. Its transcript is up-regulated in various types of solid tumors including breast cancer. However, its transcriptional regulation mechanism is still unclear. To investigate the mechanism of transcriptional regulation of LAPTM4B in human breast cancer cells, a series of luciferase reporter constructs and construct with mutated binding site for cAMP responsive element binding protein-1 (CREB1) were generated by PCR amplification and transiently transfected into breast cancer cells to determine the transcriptional activities of different promoter regions. The +10+292 promoter region was possessed the highest transcriptional activity. The ability of CREB1 to bind the LAPMT4B promoter was confirmed by electrophoretic mobility shift assay, super-shift and RNA interference experiments. Our study identified the core promoter region responsible for constitutive expression of LAPTM4B and clarified that CREB1 played an important role in LAPTM4B transcriptional regulation in human breast cancer cells.

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Relative luciferase activities from a series of 5′-deleted constructs and mutated construct.The luciferase mean values of three independence experiments performed in triplicates in MCF7, T-47D and ZR-75-1 respectively.
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pone-0057520-g003: Relative luciferase activities from a series of 5′-deleted constructs and mutated construct.The luciferase mean values of three independence experiments performed in triplicates in MCF7, T-47D and ZR-75-1 respectively.

Mentions: At 48h after transient transfection with various constructs, breast cancer cells were split for luciferase detection. The luciferase mean values of three independence experiments performed in triplicates were shown in Fig. 3. The transcriptional activity of the fragment upstream transcription start site (TSS) was found only slightly higher than negative control (pGL3-basic). In three breast cancer cell lines, fragment of +10∼+292 has the highest transcriptional activity among the six 5′-deleted constructs (Fig. 3). However, the basal transcriptional activities of fragment of +10∼+292 among the three cell lines are different, about 22%, 109% and 89% in MCF7, T-47D and ZR-75-1 respectively. The transcriptional activities of mutated constructs were significantly decreased than mutated before. The transcriptional activity decreased by approximately 80% in all the three breast cancer cell lines (Fig. 3).


cAMP responsive element binding protein-1 is a transcription factor of lysosomal-associated protein transmembrane-4 Beta in human breast cancer cells.

Zhang M, Xu JJ, Zhou RL, Zhang QY - PLoS ONE (2013)

Relative luciferase activities from a series of 5′-deleted constructs and mutated construct.The luciferase mean values of three independence experiments performed in triplicates in MCF7, T-47D and ZR-75-1 respectively.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3585361&req=5

pone-0057520-g003: Relative luciferase activities from a series of 5′-deleted constructs and mutated construct.The luciferase mean values of three independence experiments performed in triplicates in MCF7, T-47D and ZR-75-1 respectively.
Mentions: At 48h after transient transfection with various constructs, breast cancer cells were split for luciferase detection. The luciferase mean values of three independence experiments performed in triplicates were shown in Fig. 3. The transcriptional activity of the fragment upstream transcription start site (TSS) was found only slightly higher than negative control (pGL3-basic). In three breast cancer cell lines, fragment of +10∼+292 has the highest transcriptional activity among the six 5′-deleted constructs (Fig. 3). However, the basal transcriptional activities of fragment of +10∼+292 among the three cell lines are different, about 22%, 109% and 89% in MCF7, T-47D and ZR-75-1 respectively. The transcriptional activities of mutated constructs were significantly decreased than mutated before. The transcriptional activity decreased by approximately 80% in all the three breast cancer cell lines (Fig. 3).

Bottom Line: Lysosomal-associated protein transmembrane-4 beta (LAPTM4B) is a potential proto-oncogene, whose overexpression is involved in cancer occurrence and progression.However, its transcriptional regulation mechanism is still unclear.The +10+292 promoter region was possessed the highest transcriptional activity.

View Article: PubMed Central - PubMed

Affiliation: Department of Clinical laboratory, Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Cancer Hospital & Institute, Beijing, China.

ABSTRACT
Lysosomal-associated protein transmembrane-4 beta (LAPTM4B) is a potential proto-oncogene, whose overexpression is involved in cancer occurrence and progression. Its transcript is up-regulated in various types of solid tumors including breast cancer. However, its transcriptional regulation mechanism is still unclear. To investigate the mechanism of transcriptional regulation of LAPTM4B in human breast cancer cells, a series of luciferase reporter constructs and construct with mutated binding site for cAMP responsive element binding protein-1 (CREB1) were generated by PCR amplification and transiently transfected into breast cancer cells to determine the transcriptional activities of different promoter regions. The +10+292 promoter region was possessed the highest transcriptional activity. The ability of CREB1 to bind the LAPMT4B promoter was confirmed by electrophoretic mobility shift assay, super-shift and RNA interference experiments. Our study identified the core promoter region responsible for constitutive expression of LAPTM4B and clarified that CREB1 played an important role in LAPTM4B transcriptional regulation in human breast cancer cells.

Show MeSH
Related in: MedlinePlus