Knockdown of DEPTOR inhibits cell proliferation and increases chemosensitivity to melphalan in human multiple myeloma RPMI-8226 cells via inhibiting PI3K/AKT activity

Zhang, Haoran; Chen, Junmin; Zeng, Zhiyong; Que, Wenzhong

doi:10.1177/0300060513480920

Cited by 24 publications

(22 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our study also revealed that expression of P-S6 (S235/236) was significantly higher in CRC tissue than in normal colorectal mucosa (p<0.01). When greatly overexpressed, DEPTOR inhibits mTORC1 (Peterson et al, 2009;Bruneau et al, 2013;Meng et al, 2013;Zhang et al, 2013). In this study, DEPTOR was equally expressed in CRC and adjacent DOI:http://dx.doi.org/10.7314/APJCP.2014.15.11.4589 DEPTOR Expression Negatively Correlates with mTORC1 Activity and Tumor Progression in Colorectal Cancer normal colorectal mucosa.…”

Section: Discussionmentioning

confidence: 56%

DEPTOR Expression Negatively Correlates with mTORC1 Activity and Tumor Progression in Colorectal Cancer

Lai

Chen²,

Zhou³

et al. 2014

Asian Pacific Journal of Cancer Prevention

View full text Add to dashboard Cite

The mammalian target of rapamycin (mTOR) signaling pathway is upregulated in the pathogenesis of many cancers, including colorectal cancer (CRC). DEPTOR is an mTOR inhibitor whose expression is negatively regulated by mTOR. However, the role of DEPTOR in the development of CRC is not known. The aim of this study was to investigate the expression of DEPTOR and mTORC1 activity (P-S6) in a subset of CRC patients and determine their relation to tumor differentiation, invasion, nodal metastasis and disease-free survival. Here, Immunohistochemical expression of P-S6 (S235/236) and DEPTOR were evaluated in 1.5 mm tumor cores from 90 CRC patients and in 90 samples of adjacent normal mucosa by tissue microarray. The expression of P-S6 (S235/236) was upregulated in CRC, with the positive rate of P-S6 (S235/236) in CRC (63.3%) significantly higher than that in control tissues (36.7%, 30%) (p<0.05). P-S6 (S235/236) also correlated with high tumor histologic grade (p=0.002), and positive nodal metastasis (p=0.002). In contrast, the expression level of DEPTOR was correlated with low tumor histological grade (p=0.006), and negative nodal metastasis (p=0.001). Interestingly, P-S6 (S235/236) expression showed a significant negative association with the expression of DEPTOR in CRC (p=0.011, R= -0.279). However, upregulation of P-S6 (S235/236) (p=0.693) and downregulation of DEPTOR (p=0.331) in CRC were not significantly associated with overall survival. Thus, we conclude that expression of DEPTOR negatively correlates with mTORC1 activity and tumor progression in CRC. DEPTOR is a potential marker for prognostic evaluation and a target for the treatment of CRC.

show abstract

Section: Discussionmentioning

confidence: 56%

DEPTOR Expression Negatively Correlates with mTORC1 Activity and Tumor Progression in Colorectal Cancer

Lai

Chen²,

Zhou³

et al. 2014

Asian Pacific Journal of Cancer Prevention

View full text Add to dashboard Cite

show abstract

“…DEPTOR interacts with mTOR and inhibits mTORC1/2 pathways (Peterson et al, 2009). It plays an important role in proliferation (Zhang et al, 2013b), apoptosis (Zhang et al, 2013a), regulation pluripotency of embryonic stem cells (Agrawal et al, 2014), and adipogenesis . Recent studies reveal that DEPTOR is a critical upstream regulator of vascular endothelial cells (ECs) activation and is involved in the inflammatory response of ECs (Bruneau et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

p65 down-regulates DEPTOR expression in response to LPS stimulation in hepatocytes

Jin

et al. 2016

Gene

View full text Add to dashboard Cite

DEPTOR, a novel endogenous inhibitor of mTOR, plays an important role in regulating the inflammatory response in vascular endothelial cells (ECs) and in mouse skeletal muscle. However, the regulatory mechanism of DEPTOR transcription and its effects on liver inflammation are unknown presently. Here we reported the role of DEPTOR in regulating inflammatory response in mouse liver-derived Hepa1-6 cells and in a mouse model with LPS-induced hepatic inflammation. The results revealed that DEPTOR over-expression in Hepa1-6 liver cells increased the mRNA levels of the pro-inflammatory cytokines interleukin-6 (IL-6) and monocyte chemotactic protein-1 (MCP-1). Contrasting results were observed in Hepa1-6 cells with DEPTOR interference. Treatment Hepa1-6 cells with rapamycin, a specific inhibitor of mTORC1, increased MCP-1 mRNA, but have no significant effect on IL-6 mRNA. DEPTOR expression was down-regulated in Hepa1-6 cells with the treatment of inflammatory stimuli LPS or the over-expression of p65/NF-κB, a key inflammatory transcription factor. NF-κB antagonist (PDTC) and inhibitor (IκBα) blocked the effect of LPS on DEPTOR expression. The study in vivo showed that DEPTOR mRNA and protein were significantly reduced in a mouse model with LPS-induced hepatic inflammation, which was accompanied by a concurrent activation of the mTOR signaling pathway. Further, the transcriptional regulation of DEPTOR was explored, which revealed that DEPTOR promoter activity was significantly down-regulated by NF-κB. The progressive deletions and mutations demonstrated that the NF-κB binding motif situated at -145/-127 region is an essential component required for the DEPTOR promoter activity. Chromatin immunoprecipitation (ChIP) assays determined that p65 can directly interact with the DEPTOR promoter DNA. Those results indicate DEPTOR regulates liver inflammation at least partially via mTORC1 pathway, and is down-regulated by LPS through p65.

show abstract

“…Because MM cell lines generally grow in suspension or at best semi-adherently, they belong among the harder-to-manipulate cell types by transient transfection methodologies. Even though a number of papers either deal with this issue or report MM cell transfection in their methods chapter [14], [15], [16], [17], [18], [19], [20], a robustly workable and widely-used protocol has not yet emerged. Our analyses of MM cell electroporability with siRNAs were therefore not only intended to address the purely functional aspects, but also to judge whether such a protocol could i) easily be performed and replicated by other researchers in their laboratories, ii) prove cost-effective, and iii) could be applied to generate sufficient numbers of transfected cells to conduct experiments that require substantial amounts of material, such as, for example, nuclear preparations (i.e.…”

Section: Resultsmentioning

confidence: 99%

“…Growing in suspension and/or semi-adherently, HMCLs do not count as particularly amenable to transient transfection with nucleic acids. Few publications have specifically addressed this topic [12], [13] and although a roster of anecdotal evidence implies various transient transfection methodologies for use with (specific) HMCLs [14], [15], [16], [17], [18], [19], [20], no broadly-used method of choice has so far emerged – not least, because transfection efficiency is usually either perceived as low or not easily determined in the first place. RNAi knockdown experiments in HMCLs can usefully complement pharmacologic inhibition studies and also offer a chance to target undruggable proteins.…”

Section: Introductionmentioning

confidence: 99%

Efficient Transient Transfection of Human Multiple Myeloma Cells by Electroporation – An Appraisal

et al. 2014

View full text Add to dashboard Cite

Cell lines represent the everyday workhorses for in vitro research on multiple myeloma (MM) and are regularly employed in all aspects of molecular and pharmacological investigations. Although loss-of-function studies using RNA interference in MM cell lines depend on successful knockdown, no well-established and widely applied protocol for efficient transient transfection has so far emerged. Here, we provide an appraisal of electroporation as a means to introduce either short-hairpin RNA expression vectors or synthesised siRNAs into MM cells. We found that electroporation using siRNAs was much more efficient than previously anticipated on the basis of transfection efficiencies deduced from EGFP-expression off protein expression vectors. Such knowledge can even confidently be exploited in “hard-to-transfect” MM cell lines to generate large numbers of transient knockdown phenotype MM cells. In addition, special attention was given to developing a protocol that provides easy implementation, good reproducibility and manageable experimental costs.

show abstract

Knockdown of DEPTOR inhibits cell proliferation and increases chemosensitivity to melphalan in human multiple myeloma RPMI-8226 cells via inhibiting PI3K/AKT activity

Cited by 24 publications

References 29 publications

DEPTOR Expression Negatively Correlates with mTORC1 Activity and Tumor Progression in Colorectal Cancer

DEPTOR Expression Negatively Correlates with mTORC1 Activity and Tumor Progression in Colorectal Cancer

p65 down-regulates DEPTOR expression in response to LPS stimulation in hepatocytes

Efficient Transient Transfection of Human Multiple Myeloma Cells by Electroporation – An Appraisal

Contact Info

Product

Resources

About