Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Proliferation”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,261 records · Page 70
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Mutual suppression of miR-125a and Lin28b in human hepatocellular carcinoma cells

MicroRNA-125a exhibits an antiproliferative activity and is downregulated in several types of tumors, including hepatocellular carcinoma where it targets sirtuin-7, matrix metalloproteinase-11, and c-Raf. Another target of miR-125a is Lin28, a pluripotency factor that is generally undetectable in differentiated cells but is often upregulated/reactivated in tumors where it acts as an oncogenic factor promoting cell proliferation and tumor progression. In this study we show that downregulation of Lin28b by miR-125a partially accounts for its antiproliferative activity toward hepatocellular carcinoma cells. We also found that Lin28b is able to bind a conserved GGAG motif of pre-miR-125a and to inhibit its maturation in hepatocellular carcinoma cells. Reciprocal inhibition between miR-125a and Lin28b reasonably generates a positive feedback loop where reactivation of Lin-28b inhibits the expression of both miR-125a and let-7, reinforcing its own expression and leading to a marked overexpression of the mitogenic targets of the two miRNAs. On the other hand, perturbation of these circuits by overexpression of miR-125a suppresses Lin28b leading to a decreased cell proliferation. Overall, these data support a tumor suppressive role for miR-125a and contribute to the elucidation of its molecular targets.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Circular RNA hsa{sub c}ircRNA{sub 1}03809 promotes lung cancer progression via facilitating ZNF121-dependent MYC expression by sequestering miR-4302

Lung cancer characterized with malignant cell growth is the leading cause of cancer-related deaths. In recent years, several circular RNAs (circRNAs) have been reported to participate in lung cancer progression. However, the correlation between circular RNA (circRNA) and lung cancer still remains to be further investigated. In this study, we screened out a highly expressed circular RNA hsa{sub c}ircRNA{sub 1}03809 in lung cancer tissues. We showed hsa{sub c}ircRNA{sub 1}03809 could serve as a prognostic biomarker for patients with lung cancer. Furthermore, we found that hsa{sub c}ircRNA{sub 1}03809 knockdown significantly suppressed lung cancer cell proliferation and invasion in vitro and delayed tumor growth in vivo. In mechanism, we identified hsa{sub c}ircRNA{sub 1}03809 as a sponge of miR-4302 targeting ZNF121. By sequestering miR-4302, hsa{sub c}ircRNA{sub 1}03809 promoted the expression of ZNF121 which consequently enhanced MYC protein level in lung cancer cells. Through rescue assays, we demonstrated hsa{sub c}ircRNA{sub 1}03809 contributed to lung cancer cell proliferation and invasion via facilitating ZNF121-dependent MYC expression by sponging miR-4302. In conclusion, our findings illustrated a novel hsa{sub c}ircRNA{sub 1}03809/miR-4302/ZNF121/MYC regulatory signaling pathway in lung cancer progression.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

circRNA{sub 0}084043 promote malignant melanoma progression via miR-153-3p/Snail axis

Highlights: • circRNA{sub 0}084043 was significantly up-regulated in melanoma tissue. • circRNA{sub 0}084043 promotes melanoma cell proliferation, invasion and migration. • circRNA{sub 0}084043 directly binds to miR-153-3p, and Snail is directly targeted by miR-153-3p. • circRNA{sub 0}084043 act as the sponge of miR-153-3p to up-regulate Snail expression, and consequently function as an oncogene in melanoma. Circular RNAs (circRNAs) has been found to play an important role in the regulation of multiple diseases, and participate in cancer development. However, the role of circRNA in malignant melanoma has not been reported. In this study, human circRNA microarray was used to screen the dysregulated circRNA in melanoma. We found that circRNA{sub 0}084043 was significantly up-regulated in melanoma tissue, and the result was replicated in a larger sample size. High circRNA{sub 0}084043 expression was an independent risk factor of overall survival in melanoma patients. circRNA{sub 0}084043 promotes melanoma cell proliferation, invasion and migration. Bioinformatics and luciferase reporter assays confirmed that circRNA{sub 0}084043 directly binds to miR-153-3p, and Snail is directly targeted by miR-153-3p. We also demonstrated that circRNA{sub 0}084043 may act as the sponge of miR-153-3p to up-regulate Snail expression, and consequently function as an oncogene in melanoma. Overall, this result elucidates a new mechanism for circRNA{sub 0}084043 in melanoma development and provides a potential therapeutic target for melanoma patients.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

The long non-coding RNA PCSEAT exhibits an oncogenic property in prostate cancer and functions as a competing endogenous RNA that associates with EZH2

Highlights: • PCSEAT is specifically overexpressed in prostate cancer. • PCSEAT promotes the growth and motility of prostate cancer cells. • PCSEAT regulates EZH2 by competitively ‘sponge’ miRNA-143-3p and miRNA-24-2-5p. • PCSEAT may serve as a biomarker for EZH2 inhibitors. • PCSEAT can be transmitted via exosomes and function in recipient cell. Prostate cancer (PCa) is the most common malignancy and the leading cause of cancer deaths in males. Recent studies demonstrate that long non-coding RNAs (lncRNAs) are involved in many aspects of PCa. However, their biological roles in PCa remain imperfectly understood. Here, we characterized an lncRNA, PCa specific expression and EZH2-associated transcript (PCSEAT, annotated as PRCAT38), which is specifically overexpressed in PCa. We further demonstrated that knockdown of PCSEAT results in the reduction of PCa cell growth and motility, and overexpression of PCSEAT reverses these phenotypes. Furthermore, bioactive PCSEAT is incorporated into exosomes and transmitted to adjacent cells, thus promoting cell proliferation and motility. Mechanistically, we found that PCSEAT promotes cell proliferation, at least in part by affecting miR-143-3p- and miR-24-2-5p-mediated regulation of EZH2, suggesting that PCSEAT and EZH2 competitively ‘sponge’ miR-143-3p and miR-24-2-5p. Overall, our results reveal that PCSEAT is specifically overexpressed in PCa patients and a potential oncogene in PCa cells via mediating EZH2 activity, indicating that PCSEAT may be a potential therapeutic target in PCa.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Inhibition of TBK1 reduces choroidal neovascularization in vitro and in vivo

Highlights: • The expression of TBK1 and VEGF is up-regulated in CNV model. • Knockdown of TBK1 alleviates CNV formation via inhibiting VEGF expression. • TBK1 plays a critical role in the development of CNV. choroidal neovascularization (CNV), a characteristic of wet age-related macular degeneration (AMD), causes severe vision loss among elderly patients. TANK-binding kinase 1 (TBK1) is a ubiquitously expressed serine–threonine kinase and is found to induce endothelial cells proliferation, represent a novel mediator of tumor angiogenesis and exert pro-inflammatory effect. However, the role of TBK1 in choroidal neovascularization has not been investigated so far. In this study, we found that the expression of TBK1 and VEGF was up-regulated in RF/6 A cells chemical hypoxia model and laser-induced mouse CNV model. Silencing of TBK1 suppressed the proliferation and tube formation activity of RF/6 A cells. Intravitreal injection of anti-TBK1 monoclonal antibody ameliorates CNV formation. Taken together, these findings exhibit a proangiogenic role for TBK1 via upregulating the expression of VEGF, and may suggest that TBK1 inhibition offers a unique and alternative method for prevention and treatment of AMD.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

UBE2S enhances the ubiquitination of p53 and exerts oncogenic activities in hepatocellular carcinoma

Highlights: • High expression of UBE2S is significantly correlated with poor outcomes in two independent cohorts containing 845 patients. • UBE2S promotes cell proliferation and migration in HCC. • UBE2S exerts oncogenic activities via enhancing the ubiquitination of p53. Ubiquitin-conjugating enzyme E2S (UBE2S) plays pivotal roles in the progression of human cancers. However, its clinical significance and role in hepatocellular carcinoma (HCC) remain unknown. Here, we show that UBE2S is upregulated in HCC and exhibits oncogenic activities via enhancing the ubiquitination of p53. Increased expression of UBE2S was significantly correlated with higher serum AFP level, higher pathological grade, advanced TNM stage, larger tumor size, vascular invasion and unfavorable patient survivals in two independent cohorts containing a total of 845 patients with HCC. Multivariate analyses by cox regression model suggested UBE2S as an independent factor for overall survival. In vitro experiments demonstrated that UBE2S overexpression promoted, whereas UBE2S knockdown suppressed cell proliferation and migration via modulation of p53 signaling pathway. Ectopic expression of UBE2S upregulated the expression of p53 and its downstream effectors, such as p21 and Cyclin D1. Mechanistically, UBE2S enhanced the ubiquitination of p53 protein to facilitate its degradation in HCC cells. Re-expression of p53 partially attenuated the UBE2S-promoted malignant phenotypes. Collectively, our study provides compelling evidence that UBE2S is a potential prognostic factor and functions as an oncogene in HCC.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

The anti-tumor effect of regorafenib in lung squamous cell carcinoma in vitro

Highlights: • Regorafenib might be a potential therapeutic medicine for LSCC treatment. • GSK3β activation restricted the anti-tumor activity of regorafenib on LSCC. • GSK3β inhibition could sensitize the anti-proliferation effect of regorafenib. Lung squamous cell carcinoma (LSCC) is a common type of non-small-cell lung cancer (NSCLC) and lacks effective treatment. Regorafenib, an oral multikinase inhibitor, has demonstrated promising anti-tumor activity in various solid tumors. To study whether regorafenib inhibits LSCC cells, we investigate the compound in several LSCC cell lines and explore the possible mechanism. In this study, we confirmed that regorafenib had anti-proliferation effect on LSCC cell lines by inducing G0/G1 arrest. In addition, glycogen synthase kinase 3β (GSK3β) remained at the same level and Ser9 phosphorylation of GSK3β decreased with increasing incubation time and increasing regorafenib concentration in LSCC cells. GSK3β inhibition enhanced the anti-tumor activity of regorafenib. Thus, GSK3β activation restricted the anti-cancer effect of regorafenib on LSCC. In conclusion, regorafenib might be a promising drug for LSCC therapy. GSK3β might be a potential target to increase the anti-tumor effect of regorafenib in LSCC cells.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Long non-coding RNA KCNQ1OT1 modulates oxaliplatin resistance in hepatocellular carcinoma through miR-7-5p/ ABCC1 axis

Highlights: • KCNQ1OT1 was significantly up-regulated in oxaliplatin-resistant HCC cells. • Knockdown of KCNQ1OT1 inhibited the cell proliferation, migration, invasion. • KCNQ1OT1 modulated oxaliplatin resistance in HCC through miR-7-5p/ ABCC1 axis. The underlying functions of long non-coding RNAs (lncRNAs) on chemoresistance in multiple cancers have been testified. However, the function and mechanism of lncRNAs on chemoresistance in hepatocellular carcinoma are still confused. In this study, we concentrated on the function and mechanism of KCNQ1OT1 on oxaliplatin resistance in hepatocellular carcinoma. Results showed that KCNQ1OT1 was significantly up-regulated in oxaliplatin-resistant HepG2 and Huh7 cells. Moreover, knockdown of KCNQ1OT1 inhibited the cell proliferation, migration, invasion and reduced the expression of drug-resistant gene (MRP5, MDR1, LRP1). Additionally, bioinformatics analysis and dual-luciferase reporter assay showed that miR-7-5p directly targeted the 3′-UTR of miR-7-5p and ABCC1 mRNA, indicating that KCNQ1OT1 regulated the expression of ABCC1 via endogenous sponging miR-7-5p. Conclusively, KCNQ1OT1 modulated oxaliplatin resistance in hepatocellular carcinoma through miR-7-5p/ABCC1 axis, indicating a novel approach for the treatment of hepatocellular carcinoma.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

DNA copy number gain-mediated lncRNA LINC01061 upregulation predicts poor prognosis and promotes papillary thyroid cancer progression

Several DNA copy number amplifications (CNAs) have been reported in papillary thyroid cancer (PTC). However, the functional role of CNAs in PTC remains very unclear. And whether there is a correlation between long noncoding RNA (lncRNA) and CNA requires to be explored. Here, we identified a novel lncRNA LINC01061. The genomic copy number of LINC01061 is amplified, which leads to its elevated expression level in PTC tissues. Moreover, increased level of LINC01061 was correlated with aggressive clinicopathological characteristics. Functional study indicated that LINC01061 silence significantly inhibited the proliferation, cell-cycle and invasion of PTC cells in vitro and tumor growth in vivo. Mechanistically, we showed that LINC01061 interacted with miR-4316 to promote E2F6 expression. The expression of miR-4316 was downregulated in PTC tissues while that of E2F6 was upregulated. Through rescue assay, we demonstrated that LINC01061 promoted PTC cell proliferation, cell-cycle progression and invasion by regulating miR-4316/E2F6 signaling pathway. In conclusion, our research indicated that LINC01061 might be a target for PTC therapy.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

The FGF2 aptamer inhibits the growth of FGF2-FGFR pathway driven lung cancer cells

Cancers, including lung cancer, are a leading cause of death worldwide. To overcome this deadly disease, multiple modality inhibitors have been developed. These include cytotoxic agents, molecular targeted small molecules, such as tyrosine kinase inhibitors, and neutralizing antibodies. An aptamer is a short single-stranded nucleic acid molecule that is selected in vitro from a large random sequence library based on its high and specific affinity to a target molecule. Aptamers can be applied to therapeutics of various types of diseases, including cancer, due to their strong and specific neutralizing activities. However, the efficacy of aptamer-based therapy for cancer cells is not well characterized. In this study, we aimed to show that the FGF2 aptamer is effective for the treatment of FGF2 dependent lung cancer cells. We previously developed PC9GR lung cancer cells, whose proliferation is dependent on EGFR and FGF2-FGFR pathways in a cell autonomous manner. Using PC9GR cells, we demonstrate that the addition of the FGF2 aptamer induces more significant inhibition of PC9GR cell proliferation than does the addition of EGFR inhibitor alone. Furthermore, the addition of the FGF2 aptamer more significantly inhibits the downstream signals and induces apoptosis to a higher extent than does the addition of EGFR inhibitor alone. Our results show that the FGF2 aptamer inhibits the growth of FGF2-FGFR pathway-dependent lung cancer cells. The findings provide preclinical evidence that aptamers can be useful for cancer treatment.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Decreased expression of protein tyrosine kinase 6 contributes to tumor progression and metastasis in laryngeal squamous cell carcinoma

Highlights: • Overexpression of PTK6 significantly decreased cell growth, clonogenicity, invasion and migration capacity in LSCC. • PTK6 suppresses LSCC proliferation mainly by inhibiting c-myc and cyclinD1 expression. • PTK6 promotes cell apoptosis in LSCC. • PTK6 mitigated LSCC invasion and migration through regulating EMT and MMP-9. PTK6 is involved in cell proliferation, invasion and migration. Patients with lower PTK6 expression predicts poor prognosis of LSCC. However, the mechanism of PTK6 in LSCC progression remains unclear. We investigated the role of PTK6 in the pathogenesis of LSCC.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

miR-5590-3p inhibited tumor growth in gastric cancer by targeting DDX5/AKT/m-TOR pathway

Recent evidence suggests that microRNAs play important roles in the negative post-transcriptional regulators with altered expression levels found in gastric cancer (GC). Therefore, we employed explore the anti-cancer miRNA and the potential mechanisms by which miRNAs modulate GC progression. We have predicted GC miRNA expression data sets in TargetScan. miR-5590-3p is higher in adjacent nonmalignant tissue than in cancer tissue in 42 pairs of GC tissues. Functional assays, CCK-8 and colony formation assay, were used to determine the Anti-cancer role of miR-5590-3p in human GC progression. In addition, Ago2-based RIP and dual-luciferase reporter assay were conducted to study the miR-5590-3p as a direct target of DDX5. Next, Xenograft nude mouse models were used to determine the role of miR-5590-3p in GC tumorigenicity in vivo. Upregulation of miR-5590-3p suppressed GC cell proliferation, whereas downregulation of miR-5590-3p promoted GC proliferation in vitro. Furthermore, we identified DDX5 as a direct target of miR-5590-3p, and that the biological function of miR-5590-3p during GC progression in vitro and in vivo is through the DDX5/AKT/m-TOR pathway and downstream cyclinD1 and CDK2 expression. Finally, we confirmed the effect of miR-5590-3p directly targeting DDX5 on the development of gastric cancer through salvage experiments in vivo and in vitro.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Down-regulation of MAP2K1 by miR-539 inhibits hepatocarcinoma progression

Liver cancer has been considered as one of the major leading causes of cancer-related mortality. The incidence of liver cancer tends to increase in less developed regions. Increasing evidences have demonstrated that mircoRNAs (miRNAs) play crucial roles in the modulation of tumor growth and progression. Whereas, the functional role of miR-539 in hepatocellular carcinoma (HCC) is not well established. In our present study, we sought to explore biological role of miR-539 in HCC progression. qRT-PCR was utilized to evaluate the expression level of miR-539. Immunoblotting analysis, qRT-PCR and luciferase reporter assays were used for the identification of the potential target of miR-539. Proliferation, migration and invasion assays and flow cytometric were performed to assess the biological functional role of miR-539. The molecular signaling pathways related to the integration of miR-539 were also evaluated. MiR-539 was reduced in human HCC. Mitogen-activated protein kinase 1, also known as MAP2K1 was verified as the target of miR-539. Overexpression of miR-539 inhibited migration, invasion and cell proliferation, while apoptosis rate was increased. Knockdown or overexpression of MAP2K1 in HCC cell transfected with ag-miR-539 or in-miR-539 indicated that miR-539 suppresses the progression of HCC by directly targeting and regulating MAP2K1. Our results reveal that miR-539 might be a tumor suppressor in HCC, supporting a potential target for advanced therapeutic strategy for this disease.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Long noncoding RNA LINC00339 aggravates doxorubicin-induced cardiomyocyte apoptosis by targeting MiR-484

Highlights: • LncRNA LINC00339 was highly expressed in DOX stimulated primary rat cardiomyocytes and H9c2 cells. • Knockdown of LINC00339 significantly reduced primary rat cardiomyocytes and H9c2 cells proliferation and apoptosis. • LINC00339 acts as a critical pro-apoptosis lncRNA that aggravates DOX-induced cardiac remodeling by miR-484. Abnormally expressed long noncoding RNAs (lncRNAs) has been recognized as one of the key source in cardiac diseases. However, the role of lncRNA in doxorubicin (DOX)-induced cardiotoxicity remains largely unknown. In previous studies, we have screened some aberrantly expressed lncRNAs from an animal model for DOX-induced cardiotoxicity, and LINC00339 is one of the highly expressed lncRNA. In this study, we validated and further explored its regulatory mechanisms using in vitro model systems. Primary cultured myocardial cell (PC) and H9C2 cell line were treated with different concentrations of DOX and the expression of LINC00339 were markedly up-regulated. However, knockdown of endogenous LINC00339 by its siRNA improved cells proliferation activity and reduced cardiomyocyte apoptosis. Further experiments showed the opposite trend of expression between LINC00339 and miR-484. Bioinformatics analysis and luciferase reporter assay indicated that LINC00339 directly binds to miR-484. Moreover, miR-484 inhibitor abrogated the collagen synthesis inhibition induced by LINC00339. These findings reveal a novel function of the LINC00339/miR-484 axis in DOX-induced cardiotoxicity.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

CircRNA{sub 1}00290 promotes colorectal cancer progression through miR-516b-induced downregulation of FZD4 expression and Wnt/β-catenin signaling

Accumulating evidence indicates that circular RNAs (circRNA) exert crucial functions in the development and advance of cancers. CircRNA{sub 1}00290 has been reported to promote proliferation in oral cancer. However, whether it participates in colorectal cancer (CRC) remains unclear. Here, our report showed that circRNA{sub 1}00290 level was significantly increased in CRC tissues and cell lines. Besides, circRNA{sub 1}00290 expression was positively correlated with tumor metastasis while inversely correlated with prognosis. Silencing circRNA{sub 1}00290 markedly reduced cell proliferation rate, inhibited migration and invasion abilities, but promoted apoptosis in vitro. Mechanistically, our data revealed circRNA{sub 1}00290 was a competing endogenous RNA (ceRNA) of FZD4 by sponging miR-516b, leading to activation of Wnt/β-catenin pathway. Rescue assay indicated that FZD4-induced activation of β-catenin pathway is indispensable for the function of circRNA{sub 1}00290 in CRC. In summary, our study for the first time revealed a novel regulatory loop of circRNA{sub 1}00290/miR-516b/FZD4/Wnt/β-catenin implicated in CRC progression.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

High mobility group A2 (HMGA2) promotes EMT via MAPK pathway in prostate cancer

Highlights: • HMGA2 expression increases with prostate cancer progression. • Wild-type HMGA2 promotes EMT via MAPK. • Truncated HMGA2 increases cell viability and migration via non-EMT pathway. Studies have shown that High mobility group A2 (HMGA2), a non-histone protein, can promote epithelial-mesenchymal transition (EMT), which plays a critical role in prostate cancer progression and metastasis. Interestingly, full-length or wild-type HMGA2 and truncated (lacking the 3′UTR) HMGA2 isoforms are overexpressed in several cancers. However, there are no studies investigating the expression and differential roles of WT vs truncated HMGA2 isoforms in prostate cancer. Immunohistochemical staining of prostate tissue microarray revealed low membrane expression in normal epithelial prostate cells, and that expression increased with tumor grade as well as a switch from predominantly cytoplasmic HMGA2 in lower tumor grades, to mostly nuclear in high grade and bone metastatic tissue. LNCaP cells stably overexpressing wild-type HMGA2 displayed nuclear localization of HMGA2 and induction of EMT associated with increased Snail, Twist and vimentin expression compared to LNCaP Neo control cells, as shown by immunofluorescence and western blot analyses. This was associated with increased cell migration on collagen shown using boyden chamber assay. Conversely, LNCaP cells overexpressing truncated HMGA2 showed cytoplasmic HMGA2 expression that did not induce EMT yet displayed increased cell proliferation and migration compared to LNCaP Neo. Both wild-type and truncated HMGA2 increased levels of phospho-ERK, and interestingly, treatment with U0126, MAPK inhibitor, antagonized wild-type HMGA2-mediated EMT and cell migration, but did not affect truncated HMGA2-mediated cell proliferation or migration. Therefore, although both wild-type and truncated HMGA2 may promote prostate tumor progression, wild-type HMGA2 acts by inducing EMT via MAPK pathway.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Platelet-derived growth factor receptor alpha (PDGFRα) is overexpressed in NK/T-cell lymphoma and mediates cell survival

Nasal-type natural killer/T-cell lymphoma (NKTCL) is a subtype of non-Hodgkin lymphoma (NHL) that is clinically aggressive and has a poor prognosis. Platelet-derived growth factor receptors (PDGFRs) and their ligands (PDGFs) play important roles in angiogenesis, cancer cell proliferation, survival, migration and poor prognosis in various tumours. However, the significance of PDGFRs in NKTCL remains unknown. Herein, the present study aimed to investigate the important role of PDGFRα in pathogenesis, progression and prognisis of NKTCL. Firstly, we performed immunohistochemical staining, qRT-PCR and western blotting to determine PDGFRα expression in formalin-fixed, paraffin-embedded tissue sections from 78 NKTCL cases and in cell lines. Secondly, correlations between PDGFRα expression and NKTCL clinical parameters and prognosis were analysed. Moreover, a biological assessment of PDGFRα blockade in two NKTCL cell lines was conducted through proliferation assay, cell-cycle evaluation and apoptosis detection by flow cytometry analyses. Furthermore, we detected in vivo activity of imatinib in mouse model of NKTCL. We found that the expression of PDGFRα was significantly higher in NKTCL tissues compared to the reactive lymphoid hyperplasia of the nasopharynx (P = 0.028). High PDGFRα expression was strongly associated with a high LDH level (P = 0.028) and III-IV stage (P = 0.013). NKTCL patients with high PDGFRα expression displayed a reduced median overall survival time and progression-free survival time when compared with those with low PDGFRα expression (P = 0.011, P = 0.005, respectively). Cox multivariate analysis showed that III-IV stage (P = 0.024) and high PDGFRα expression (P = 0.003) were independent prognostic factors in NKTCL patients. Biological assessment assays in two NKTCL cell lines revealed that a specific PDGFR antagonist, imatinib, inhibited cell viability, blocked cell cycle progression at G0/G1 stage and induced apoptosis. Similarly, the in vivo assay showed that imatinib delayed mouse model tumour growth. In conclusion, NKTCL tumour cells have prominent PDGFRα expression, which can serve as a candidate prognostic marker. PDGFR antagonists have significant biological effect on NKTCL and may be useful therapeutic agents for treatment of NKTCL.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Identification and characterization of a novel phosphoregulatory site on cyclin-dependent kinase 5

Highlights: • Identification of a novel phosphosite on Cyclin-dependent kinase 5 (CDK5). • Elucidation of the mechanism by which the phosphosite negatively regulates CDK5 activity. • Potential role for this phosphoevent in regulating cellular proliferation-migration dichotomy. Cyclin-dependent kinase 5 (CDK5) is a serine/threonine kinase essential for embryonic development whose overactivation has been implicated in several pathologies including neurodegeneration, cancer cell metastasis and type II diabetes. Therefore, it is important to investigate molecular mechanism(s) that mediate regulation of CDK5 activity. Here we identify and characterize a novel phosphoregulatory site on CDK5. Our mass spectrometry analysis identified seven putative phosphorylation sites on CDK5. Using phosphomimetic and non-phosphorylatable mutants, we determined that phosphorylation of S47, one of the identified sites, renders the kinase catalytically inactive. The inactivation of the kinase due to the phosphomimetic change at S47 results from inhibition of its interaction with its cognate activator, p35. We connect the effect of this regulatory event to a cellular phenotype by showing that the S47D CDK5 mutant inhibits cell migration and promotes cell proliferation. Together, these results have uncovered a potential physiological mechanism to regulate CDK5 activity. The evolutionary placement of a phosphorylatable residue (S/T) at this position not only in CDK5 but also in the majority of other CDK family members suggests that this phosphosite may represent a shared regulatory mechanism across the CDK family.

60 APPLIED LIFE SCIENCES↗