||The role of Specificity protein (Sp1) expression regulated by internal ribosomal entry site (IRES) in tumorigenesis and metastasis
||Institute of Basic Medical Sciences
internal ribosomal entry site (IRES)
internal ribosomal entry site (IRES)
轉錄因子特異性蛋白質(Sp1)，表現在哺乳類細胞中且參與許多細胞的生理作用。此外Sp1會大量累積及表現在人類的癌症組織中，並且Sp1的表現量與腫瘤的惡性程度相關；我們先前的研究指出在缺氧的狀況下，Sp1會藉由IRES的機制大量表現在細胞當中，此研究提供在外在壓力與病理的狀況下，可以透過IRES的機制使Sp1大量表現於細胞當中。本研究的目的是在探討Sp1藉由IRES機制調控其表現量於腫瘤形成及轉移。首先，我們發現Sp1蛋白質會大量表現在肺癌病患的肺組織中，並且透過轉譯調控的方式來增加其表現量。進一步我們利用RNA-免疫沉澱法分析，發現nucleolin能夠藉由GAR domain結合在Sp1 5端非轉譯區並且促使Sp1 IRES活化以增加Sp1的表現量。使用gefitinib， LY294002和MK2206等抑制劑，可以顯著抑制Sp1 IRES的活化，證實EGFR下游的訊息傳遞能夠透過Akt的活化並調控Sp1的表現量。我們也證實在肺癌的病程中，癌細胞能藉由EGFR下游的訊息傳遞磷酸化nucleolin上蘇胺酸641/707的位置，使nucleolin活化並且作為ITAF結合在Sp1 5端非轉譯區，藉此增加Sp1的表現量；最近的研究也指出癌組織中Sp1的表現量下降有利於腫瘤的惡化；本研究中我們也釐清，癌細胞能透過IRES的機制導致Sp1的表現量下降以利於腫瘤的惡化。我們利用Sp1 5端非轉譯區的序列在試管內合成RNA探針，並用質譜分析的方式找到nm23與hnRNPA2/B1可以結合在Sp1 5端非轉譯區。nm23能夠透過磷酸化Sp1上蘇胺酸739的位置以增加Sp1蛋白質的穩定性，並與hnRNPA2/B1形成複合體結合在Sp1 5端非轉譯區。利用基因默化(silence)降低nm23與hnRNPA2/B1的蛋白質表現量可以抑制Sp1 IRES的活化並增加肺癌細胞移動的能力。進一步我們也分析了肺癌病人的肺組織，發現Sp1與nm23低表現量的病人有較差的癒後及活存率。此外，我們也發現降低nm23蛋白質表現量，可以減少hnRNPA2/B1的蛋白質穩定性以抑制Sp1 IRES的活化及Sp1的表現。綜合以上實驗的結果，我們證實並釐清nucleolin, nm23及hnRNPA2/B1如何調控Sp1在肺癌細胞中的表現量，以利於肺癌的進程成及惡化。
The transcription factor, Specificity protein-1 (Sp1) is expressed in mammalian cells and involved in many cellular processes. Sp1 was accumulated in several cancer types and the Sp1 levels correlated with tumor stages. Our previous study indicated that Sp1 is accumulated during hypoxia in an internal ribosomal entry site (IRES)-dependent manner. This study provided evidences that Sp1 accumulation is IRES-mediated manner in stressful or pathological conditions. The overall objective of this study is to investigate the regulation of Sp1 levels through IRES-dependent manner in tumorigenesis and metastasis. First, we found that the Sp1 was induced strongly at the protein level, but not in the mRNA level, in lung tumor tissue, indicating that translational regulation might contribute to the Sp1 accumulation during tumorigenesis. A further study showed that the translation of Sp1 was dramatically induced through an IRES-dependent pathway. RNA immuniprecipitation analysis of proteins bound to the 5-untranslated region (5-UTR) of Sp1 identified interacting protein-nucleolin. We found nucleolin positively facilitates Sp1 IRES activation. Further analysis of the interaction between nucleolin and the 5-UTR of Sp1 mRNA revealed that the GAR domain was important for IRES-mediated translation of Sp1. Moreover, gefitinib, LY294002 and MK2206 compounds inhibited IRES-mediated Sp1 translation, implying that activation of the epithelial growth factor receptor (EGFR) pathway via Akt activation triggers the IRES pathway. EGFR activation-mediated nucleolin phosphorylated at Thr641 and Thr707 was recruited to the 5-UTR of Sp1 as an IRES trans-acting factor (ITAF) to modulate Sp1 translation during lung cancer formation. Furthermore, recent studies have indicated that a decrease in Sp1 level is beneficial to the lung cancer malignancy. We also clarified the decrease of Sp1 levels was regulated through IRES-dependent manner in cancer malignancy. Herein, we used in vitro transcript 5-UTR of Sp1 as probe and analyzed interacting proteins by LC/MS/MS. We found nm23 and hnRNPA2/B1 as interacting proteins in Sp1 5-UTR. We demonstrated that nm23 not only increased the phosphorylation of Sp1 at Thr739 to enhance the protein stability of Sp1 but also formed a complex with hnRNPA2/B1 that was recruited to the 5'-UTR of Sp1 mRNA. Knocking down nm23 or hnRNPA2/B1 decreased Sp1 expression in a cap-independent manner, suggesting that nm23 and hnRNPA2/B1 contributed to the IRES-mediated translational activity of Sp1. Knocking down nm23 or hnRNPA2/B1 also increased the migratory activity of lung cancer cell lines. Furthermore, patients with lung cancer with poor prognosis had low levels of Sp1 and nm23, suggesting an association between nm23/Sp1 levels and survival rate. Studies performed to elucidate the mechanism underlying this relationship indicated that a decrease in nm23 levels in the lung cancer cells with more malignant activity inhibited hnRNPA2/B1 protein stability, and thus subsequently decreased the recruitment of hnRNPA2/B1 to the 5'-UTR of Sp1 mRNA, repressing Sp1 expression through inhibition of the cap-independent transcriptional activity. Taken together, these results suggest that understanding the relationship between nucleolin, nm23, hnRNPA2/B1, and Sp1 in regulating lung cancer tumorigenesis and malignancy will be beneficial of lung cancer.
I. Specificity protein-1 (Sp1) 1
1. The overview of Sp1 1
2. Post-translational modifications of Sp1 1
3. Regulation of Sp1 in tumorigenesis and metastasis 2
II. Protein synthesis 4
1. Cap-dependent translation 4
2. Cap-independent translation 4
III. Nucleolin 6
1. Basic concept of nucleolin 6
2. The role of nucleolin in cancer formation 7
IV. Non-metastatic gene-23 (Nm23) 7
V. Heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNPA2/B1) 8
VI. Research aims 9
Material and methods 10
1. Cap-independent translational activity contributes to Sp1 accumulation during tumorigenesis 21
2. Nucleolin is involved in cap-independent translation of Sp1 22
3. GAR domain of nucleolin is important for the interaction with Sp1 IRES elements 24
4. Phosphorylation of nucleolin at Thr641/707 facilitates Sp1 IRES activity 25
5. Epidermal growth factor (EGF) signaling enhances Sp1 IRES activation 26
6. Depletion of nm23 enhances invasive phenotype and downregulates Sp1 expression in cancer cells 27
7. Low expression levels of Sp1 and nm23 are correlated with poor prognosis in patients with lung cancer 28
8. Nm23-mediated Sp1 expression is involved in EMT of lung cancer cells. 29
9. Sp1 is critical for nm23-mediated lung cancer progression 30
10. Nm23-stabilized hnRNPA2/B1 positively regulates Sp1 expression through a cap-independent translation pathway 30
11. Knockdown of hnRNPA2/B1 decreases Sp1 expression to enhance cancer cell migration 31
Figure 1. Sp1 is accumulated in tumorigenesis. 53
Figure 2. Sp1 5'-UTR contains internal ribosomal entry site (IRES) element. 55
Figure 3. Nucleolin is involved in IRES-mediated translation of Sp1. 56
Figure 4. Nucleolin increases Sp1 expression through enhancing ribosome recruitment. 58
Figure 5. Nucleolin does not affect the Sp1 protein stability. 60
Figure 6. GAR-domain of nucleolin interacts with 5-UTR of Sp1 mRNA. 62
Figure 7. Overexpression of nucleolin increase cap-independent translation. 63
Figure 8. Phosphorylation at Thr641/Thr707 residues of nucleolin is critical for IRES-mediated translation of Sp1. 64
Figure 9. EGF enhances Sp1 IRES-mediated translation. 65
Figure 10. Akt activation involves in nucleolin phosphorylation at Thr641/707. 67
Figure 11. Nucleolin induces Sp1 expression and increases cell proliferation. 69
Figure 12. The role of nm23 in Sp1 expression. 71
Figure 13. The relevance between Sp1/nm23 levels and the prognosis of lung cancer patients. 72
Figure 14. The role of nm23-mediated Sp1 expression in epithelial and mesenchymal transition of lung cancer cells. 74
Figure 15. The role of nm23-mediated Sp1 expression on lung cancer malignancy. 76
Figure 16. The effect of nm23 interacted with hnRNPA2/B1 on the Sp1 expression. 78
Figure 17.The effect of hnRNPA2/B1 on cancer cell invasive phenotype and migration ability. 80
Figure 18. The correlation between nm23, hnRNPA2/B1 and Sp1 on the different lung cancer stage. 83
Table 1. Characteristics of lung cancer patients which are involved in determining Sp1 and Nm23 expression by Immunohistochemistry staining 84
Appendix 1 85
Appendix 2 86
Appendix 3 87
Appendix 4 88
Appendix 5 89
Appendix 6 90
Curriculum vitae 91
Published thesis (First author)………………………………………………92
Abdelmohsen K, Tominaga K, Lee EK, Srikantan S, Kang MJ, Kim MM et al (2011). Enhanced translation by nucleolin via G-rich elements in coding and non-coding regions of target mRNAs. Nucleic Acids Res 39: 8513-8530.
Abdelmohsen K, Gorospe M (2012). RNA-binding protein nucleolin in disease. RNA Biol 9: 799-808.
Antonucci L, D'Amico D, Di Magno L, Coni S, Di Marcotullio L, Cardinali B et al (2014). CNBP regulates wing development in Drosophila melanogaster by promoting IRES-dependent translation of dMyc. Cell Cycle 13: 434-439.
Arguelles S, Camandola S, Cutler RG, Ayala A, Mattson MP (2014). Elongation factor 2 diphthamide is critical for translation of two IRES-dependent protein targets, XIAP and FGF2, under oxidative stress conditions. Free Radic Biol Med 67: 131-138.
Beishline K, Azizkhan-Clifford J (2015). Sp1 and the 'hallmarks of cancer'. FEBS J 282: 224-258.
Bevilacqua G, Sobel ME, Liotta LA, Steeg PS (1989). Association of low nm23 RNA levels in human primary infiltrating ductal breast carcinomas with lymph node involvement and other histopathological indicators of high metastatic potential. Cancer Res 49: 5185-5190.
Boissan M, De Wever O, Lizarraga F, Wendum D, Poincloux R, Chignard N et al (2010). Implication of metastasis suppressor NM23-H1 in maintaining adherens junctions and limiting the invasive potential of human cancer cells. Cancer Res 70: 7710-7722.
Bonello MR, Khachigian LM (2004). Fibroblast growth factor-2 represses platelet-derived growth factor receptor-alpha (PDGFR-alpha) transcription via ERK1/2-dependent Sp1 phosphorylation and an atypical cis-acting element in the proximal PDGFR-alpha promoter. J Biol Chem 279: 2377-2382.
Bonofiglio D, Qi H, Gabriele S, Catalano S, Aquila S, Belmonte M et al (2008). Peroxisome proliferator-activated receptor gamma inhibits follicular and anaplastic thyroid carcinoma cells growth by upregulating p21Cip1/WAF1 gene in a Sp1-dependent manner. Endocr Relat Cancer 15: 545-557.
Bouvet P, Diaz JJ, Kindbeiter K, Madjar JJ, Amalric F (1998). Nucleolin interacts with several ribosomal proteins through its RGG domain. J Biol Chem 273: 19025-19029.
Bouwman P, Philipsen S (2002). Regulation of the activity of Sp1-related transcription factors. Mol Cell Endocrinol 195: 27-38.
Chang WC, Hung JJ (2012). Functional role of post-translational modifications of Sp1 in tumorigenesis. J Biomed Sci 19: 94.
Chen CY, Yang SC, Lee KH, Yang X, Wei LY, Chow LP et al (2014). The antitumor agent PBT-1 directly targets HSP90 and hnRNP A2/B1 and inhibits lung adenocarcinoma growth and metastasis. J Med Chem 57: 677-685.
Chen LL, Kung YA, Weng KF, Lin JY, Horng JT, Shih SR (2013). Enterovirus 71 infection cleaves a negative regulator for viral internal ribosomal entry site-driven translation. J Virol 87: 3828-3838.
Choi JA, Jung YS, Kim JY, Kim HM, Lim IK (2015). Inhibition of breast cancer invasion by TIS21-Akt1-Sp1-Nox4 pathway targeting actin nucleators, mDia genes. Oncogene.
Chuang CW, Pan MR, Hou MF, Hung WC (2013). Cyclooxygenase-2 up-regulates CCR7 expression via AKT-mediated phosphorylation and activation of Sp1 in breast cancer cells. J Cell Physiol 228: 341-348.
Chuang JY, Wang YT, Yeh SH, Liu YW, Chang WC, Hung JJ (2008). Phosphorylation by c-Jun NH2-terminal kinase 1 regulates the stability of transcription factor Sp1 during mitosis. Mol Biol Cell 19: 1139-1151.
Chuang JY, Wang SA, Yang WB, Yang HC, Hung CY, Su TP et al (2012). Sp1 phosphorylation by cyclin-dependent kinase 1/cyclin B1 represses its DNA-binding activity during mitosis in cancer cells. Oncogene 31: 4946-4959.
Cobbold LC, Wilson LA, Sawicka K, King HA, Kondrashov AV, Spriggs KA et al (2010). Upregulated c-myc expression in multiple myeloma by internal ribosome entry results from increased interactions with and expression of PTB-1 and YB-1. Oncogene 29: 2884-2891.
Cui W, Huang Z, He H, Gu N, Qin G, Lv J et al (2015). MiR-1188 at the imprinted Dlk1-Dio3 domain acts as a tumor suppressor in hepatoma cells. Mol Biol Cell 26: 1416-1427.
Damiano F, Rochira A, Tocci R, Alemanno S, Gnoni A, Siculella L (2013). hnRNP A1 mediates the activation of the IRES-dependent SREBP-1a mRNA translation in response to endoplasmic reticulum stress. Biochem J 449: 543-553.
De Siervi A, Marinissen M, Diggs J, Wang XF, Pages G, Senderowicz A (2004). Transcriptional activation of p21(waf1/cip1) by alkylphospholipids: role of the mitogen-activated protein kinase pathway in the transactivation of the human p21(waf1/cip1) promoter by Sp1. Cancer Res 64: 743-750.
Dickinson LA, Kohwi-Shigematsu T (1995). Nucleolin is a matrix attachment region DNA-binding protein that specifically recognizes a region with high base-unpairing potential. Mol Cell Biol 15: 456-465.
Dmitriev SE, Terenin IM, Andreev DE, Ivanov PA, Dunaevsky JE, Merrick WC et al (2010). GTP-independent tRNA delivery to the ribosomal P-site by a novel eukaryotic translation factor. J Biol Chem 285: 26779-26787.
Dobson T, Chen J, Krushel LA (2013). Dysregulating IRES-dependent translation contributes to overexpression of oncogenic Aurora A Kinase. Mol Cancer Res 11: 887-900.
Dowling P, Pollard D, Larkin A, Henry M, Meleady P, Gately K et al (2015). Abnormal levels of heterogeneous nuclear ribonucleoprotein A2B1 (hnRNPA2B1) in tumour tissue and blood samples from patients diagnosed with lung cancer. Mol Biosyst 11: 743-752.
Dynan WS, Tjian R (1983). The promoter-specific transcription factor Sp1 binds to upstream sequences in the SV40 early promoter. Cell 35: 79-87.
Fox JT, Shin WK, Caudill MA, Stover PJ (2009). A UV-responsive internal ribosome entry site enhances serine hydroxymethyltransferase 1 expression for DNA damage repair. J Biol Chem 284: 31097-31108.
Gerbasi VR, Link AJ (2007). The myotonic dystrophy type 2 protein ZNF9 is part of an ITAF complex that promotes cap-independent translation. Mol Cell Proteomics 6: 1049-1058.
Ghisolfi L, Kharrat A, Joseph G, Amalric F, Erard M (1992). Concerted activities of the RNA recognition and the glycine-rich C-terminal domains of nucleolin are required for efficient complex formation with pre-ribosomal RNA. Eur J Biochem 209: 541-548.
Gingras AC, Raught B, Sonenberg N (1999). eIF4 initiation factors: effectors of mRNA recruitment to ribosomes and regulators of translation. Annu Rev Biochem 68: 913-963.
Goncharuk VN, del-Rosario A, Kren L, Anwar S, Sheehan CE, Carlson JA et al (2004). Co-downregulation of PTEN, KAI-1, and nm23-H1 tumor/metastasis suppressor proteins in non-small cell lung cancer. Ann Diagn Pathol 8: 6-16.
Gonzalez-Herrera IG, Prado-Lourenco L, Pileur F, Conte C, Morin A, Cabon F et al (2006). Testosterone regulates FGF-2 expression during testis maturation by an IRES-dependent translational mechanism. FASEB J 20: 476-478.
Goto Y, Sueoka E, Chiba H, Fujiki H (1999). Significance of heterogeneous nuclear ribonucleoprotein B1 as a new early detection marker for oral squamous cell carcinoma. Jpn J Cancer Res 90: 1358-1363.
Graber TE, Baird SD, Kao PN, Mathews MB, Holcik M (2010). NF45 functions as an IRES trans-acting factor that is required for translation of cIAP1 during the unfolded protein response. Cell Death Differ 17: 719-729.
Grover R, Candeias MM, Fahraeus R, Das S (2009). p53 and little brother p53/47: linking IRES activities with protein functions. Oncogene 28: 2766-2772.
Hartsough MT, Steeg PS (2000). Nm23/nucleoside diphosphate kinase in human cancers. J Bioenerg Biomembr 32: 301-308.
He Y, Smith R (2009). Nuclear functions of heterogeneous nuclear ribonucleoproteins A/B. Cell Mol Life Sci 66: 1239-1256.
Hershey JW (1991). Translational control in mammalian cells. Annu Rev Biochem 60: 717-755.
Hershey PE, McWhirter SM, Gross JD, Wagner G, Alber T, Sachs AB (1999). The Cap-binding protein eIF4E promotes folding of a functional domain of yeast translation initiation factor eIF4G1. J Biol Chem 274: 21297-21304.
Hsu NY, Chen CY, Hsu CP, Lin TY, Chou MC, Chiou SH et al (2007). Prognostic significance of expression of nm23-H1 and focal adhesion kinase in non-small cell lung cancer. Oncol Rep 18: 81-85.
Hsu TI, Wang MC, Chen SY, Yeh YM, Su WC, Chang WC et al (2012). Sp1 expression regulates lung tumor progression. Oncogene 31: 3973-3988.
Hsu TI, Lin SC, Lu PS, Chang WC, Hung CY, Yeh YM et al (2015). MMP7-mediated cleavage of nucleolin at Asp255 induces MMP9 expression to promote tumor malignancy. Oncogene 34: 826-837.
Huang C, Xie K (2012). Crosstalk of Sp1 and Stat3 signaling in pancreatic cancer pathogenesis. Cytokine Growth Factor Rev 23: 25-35.
Hung CY, Yang WB, Wang SA, Hsu TI, Chang WC, Hung JJ (2014). Nucleolin enhances internal ribosomal entry site (IRES)-mediated translation of Sp1 in tumorigenesis. Biochim Biophys Acta 1843: 2843-2854.
Ishikawa F, Matunis MJ, Dreyfuss G, Cech TR (1993). Nuclear proteins that bind the pre-mRNA 3' splice site sequence r(UUAG/G) and the human telomeric DNA sequence d(TTAGGG)n. Mol Cell Biol 13: 4301-4310.
Jang SK, Krausslich HG, Nicklin MJ, Duke GM, Palmenberg AC, Wimmer E (1988). A segment of the 5' nontranslated region of encephalomyocarditis virus RNA directs internal entry of ribosomes during in vitro translation. J Virol 62: 2636-2643.
Kadonaga JT, Carner KR, Masiarz FR, Tjian R (1987). Isolation of cDNA encoding transcription factor Sp1 and functional analysis of the DNA binding domain. Cell 51: 1079-1090.
Katsimpoula S, Patrinou-Georgoula M, Makrilia N, Dimakou K, Guialis A, Orfanidou D et al (2009). Overexpression of hnRNPA2/B1 in bronchoscopic specimens: a potential early detection marker in lung cancer. Anticancer Res 29: 1373-1382.
Kawakubo Y, Sato Y, Koh T, Kono H, Kameya T (1997). Expression of nm23 protein in pulmonary adenocarcinomas: inverse 1orrelation to tumor progression. Lung Cancer 17: 103-113.
Kim JH, Park SM, Park JH, Keum SJ, Jang SK (2011). eIF2A mediates translation of hepatitis C viral mRNA under stress conditions. EMBO J 30: 2454-2464.
Kim WY, Jang JY, Jeon YK, Chung DH, Kim YG, Kim CW (2014). Syntenin increases the invasiveness of small cell lung cancer cells by activating p38, AKT, focal adhesion kinase and SP1. Exp Mol Med 46: e90.
Komar AA, Hatzoglou M (2005). Internal ribosome entry sites in cellular mRNAs: mystery of their existence. J Biol Chem 280: 23425-23428.
Komar AA, Hatzoglou M (2011). Cellular IRES-mediated translation: the war of ITAFs in pathophysiological states. Cell Cycle 10: 229-240.
Kong LM, Liao CG, Fei F, Guo X, Xing JL, Chen ZN (2010). Transcription factor Sp1 regulates expression of cancer-associated molecule CD147 in human lung cancer. Cancer Sci 101: 1463-1470.
Kong LM, Liao CG, Zhang Y, Xu J, Li Y, Huang W et al (2014). A regulatory loop involving miR-22, Sp1, and c-Myc modulates CD147 expression in breast cancer invasion and metastasis. Cancer Res 74: 3764-3778.
Kozak M (1986). Point mutations define a sequence flanking the AUG initiator codon that modulates translation by eukaryotic ribosomes. Cell 44: 283-292.
Kozak M (2002). Pushing the limits of the scanning mechanism for initiation of translation. Gene 299: 1-34.
Lagger G, Doetzlhofer A, Schuettengruber B, Haidweger E, Simboeck E, Tischler J et al (2003). The tumor suppressor p53 and histone deacetylase 1 are antagonistic regulators of the cyclin-dependent kinase inhibitor p21/WAF1/CIP1 gene. Mol Cell Biol 23: 2669-2679.
Lee MY, Jeong WJ, Oh JW, Choi KY (2009). NM23H2 inhibits EGF- and Ras-induced proliferation of NIH3T3 cells by blocking the ERK pathway. Cancer Lett 275: 221-226.
Leon K, Boulo T, Musnier A, Morales J, Gauthier C, Dupuy L et al (2014). Activation of a GPCR leads to eIF4G phosphorylation at the 5' cap and to IRES-dependent translation. J Mol Endocrinol 52: 373-382.
Leone A, Flatow U, King CR, Sandeen MA, Margulies IM, Liotta LA et al (1991). Reduced tumor incidence, metastatic potential, and cytokine responsiveness of nm23-transfected melanoma cells. Cell 65: 25-35.
Lewis SM, Holcik M (2008). For IRES trans-acting factors, it is all about location. Oncogene 27: 1033-1035.
Li L, Davie JR (2010). The role of Sp1 and Sp3 in normal and cancer cell biology. Ann Anat 192: 275-283.
Luo J, Wang X, Xia Z, Yang L, Ding Z, Chen S et al (2015). Transcriptional factor specificity protein 1 (SP1) promotes the proliferation of glioma cells by up-regulating midkine (MDK). Mol Biol Cell 26: 430-439.
Marino N, Nakayama J, Collins JW, Steeg PS (2012). Insights into the biology and prevention of tumor metastasis provided by the Nm23 metastasis suppressor gene. Cancer Metastasis Rev 31: 593-603.
Matsuyama S, Goto Y, Sueoka N, Ohkura Y, Tanaka Y, Nakachi K et al (2000). Heterogeneous nuclear ribonucleoprotein B1 expressed in esophageal squamous cell carcinomas as a new biomarker for diagnosis. Jpn J Cancer Res 91: 658-663.
McCorkle JR, Leonard MK, Kraner SD, Blalock EM, Ma D, Zimmer SG et al (2014). The metastasis suppressor NME1 regulates expression of genes linked to metastasis and patient outcome in melanoma and breast carcinoma. Cancer Genomics Proteomics 11: 175-194.
Milanini-Mongiat J, Pouyssegur J, Pages G (2002). Identification of two Sp1 phosphorylation sites for p42/p44 mitogen-activated protein kinases: their implication in vascular endothelial growth factor gene transcription. J Biol Chem 277: 20631-20639.
Okabe-Kado J, Kasukabe T (2003). Physiological and pathological relevance of extracellular NM23/NDP kinases. J Bioenerg Biomembr 35: 89-93.
Opitz OG, Rustgi AK (2000). Interaction between Sp1 and cell cycle regulatory proteins is important in transactivation of a differentiation-related gene. Cancer Res 60: 2825-2830.
Palacios F, Schweitzer JK, Boshans RL, D'Souza-Schorey C (2002). ARF6-GTP recruits Nm23-H1 to facilitate dynamin-mediated endocytosis during adherens junctions disassembly. Nat Cell Biol 4: 929-936.
Parsyan A, Shahbazian D, Martineau Y, Petroulakis E, Alain T, Larsson O et al (2009). The helicase protein DHX29 promotes translation initiation, cell proliferation, and tumorigenesis. Proc Natl Acad Sci U S A 106: 22217-22222.
Pathi S, Jutooru I, Chadalapaka G, Nair V, Lee SO, Safe S (2012). Aspirin inhibits colon cancer cell and tumor growth and downregulates specificity protein (Sp) transcription factors. PLoS One 7: e48208.
Peebles KA, Dwyer-Nield LD, Malkinson AM (2007). Altered expression of splicing factor, heterogeneous nuclear ribonucleoprotein A2/B1, in mouse lung neoplasia. Mol Carcinog 46: 887-900.
Pestova TV, de Breyne S, Pisarev AV, Abaeva IS, Hellen CU (2008). eIF2-dependent and eIF2-independent modes of initiation on the CSFV IRES: a common role of domain II. EMBO J 27: 1060-1072.
Redondo N, Sanz MA, Steinberger J, Skern T, Kusov Y, Carrasco L (2012). Translation directed by hepatitis A virus IRES in the absence of active eIF4F complex and eIF2. PLoS One 7: e52065.
Robert F, Kapp LD, Khan SN, Acker MG, Kolitz S, Kazemi S et al (2006). Initiation of protein synthesis by hepatitis C virus is refractory to reduced eIF2.GTP.Met-tRNA(i)(Met) ternary complex availability. Mol Biol Cell 17: 4632-4644.
Schneider HR, Issinger OG (1989). Growth-dependent modulation of casein kinase II and its substrate nucleolin in primary human cell cultures and HeLa cells. Biochim Biophys Acta 1014: 98-100.
Semler BL, Waterman ML (2008). IRES-mediated pathways to polysomes: nuclear versus cytoplasmic routes. Trends Microbiol 16: 1-5.
Sharathchandra A, Lal R, Khan D, Das S (2012). Annexin A2 and PSF proteins interact with p53 IRES and regulate translation of p53 mRNA. RNA Biol 9: 1429-1439.
Shatsky IN, Dmitriev SE, Terenin IM, Andreev DE (2010). Cap- and IRES-independent scanning mechanism of translation initiation as an alternative to the concept of cellular IRESs. Mol Cells 30: 285-293.
Shen N, Yan F, Pang J, Wu LC, Al-Kali A, Litzow MR et al (2014). A nucleolin-DNMT1 regulatory axis in acute myeloid leukemogenesis. Oncotarget 5: 5494-5509.
Shi Y, Sharma A, Wu H, Lichtenstein A, Gera J (2005). Cyclin D1 and c-myc internal ribosome entry site (IRES)-dependent translation is regulated by AKT activity and enhanced by rapamycin through a p38 MAPK- and ERK-dependent pathway. J Biol Chem 280: 10964-10973.
Shi Y, Frost PJ, Hoang BQ, Benavides A, Sharma S, Gera JF et al (2008). IL-6-induced stimulation of c-myc translation in multiple myeloma cells is mediated by myc internal ribosome entry site function and the RNA-binding protein, hnRNP A1. Cancer Res 68: 10215-10222.
Stoneley M, Willis AE (2004). Cellular internal ribosome entry segments: structures, trans-acting factors and regulation of gene expression. Oncogene 23: 3200-3207.
Sueoka E, Sueoka N, Goto Y, Matsuyama S, Nishimura H, Sato M et al (2001). Heterogeneous nuclear ribonucleoprotein B1 as early cancer biomarker for occult cancer of human lungs and bronchial dysplasia. Cancer Res 61: 1896-1902.
Sueoka E, Sueoka N, Iwanaga K, Sato A, Suga K, Hayashi S et al (2005). Detection of plasma hnRNP B1 mRNA, a new cancer biomarker, in lung cancer patients by quantitative real-time polymerase chain reaction. Lung Cancer 48: 77-83.
Suske G, Bruford E, Philipsen S (2005). Mammalian SP/KLF transcription factors: bring in the family. Genomics 85: 551-556.
Suzuki E, Ota T, Tsukuda K, Okita A, Matsuoka K, Murakami M et al (2004). nm23-H1 reduces in vitro cell migration and the liver metastatic potential of colon cancer cells by regulating myosin light chain phosphorylation. Int J Cancer 108: 207-211.
Sze KM, Wong KL, Chu GK, Lee JM, Yau TO, Ng IO (2011). Loss of phosphatase and tensin homolog enhances cell invasion and migration through AKT/Sp-1 transcription factor/matrix metalloproteinase 2 activation in hepatocellular carcinoma and has clinicopathologic significance. Hepatology 53: 1558-1569.
Tajrishi MM, Tuteja R, Tuteja N (2011). Nucleolin: The most abundant multifunctional phosphoprotein of nucleolus. Commun Integr Biol 4: 267-275.
Takacs-Vellai K (2014). The metastasis suppressor Nm23 as a modulator of Ras/ERK signaling. J Mol Signal 9: 4.
Tang YA, Chen CH, Sun HS, Cheng CP, Tseng VS, Hsu HS et al (2015). Global Oct4 target gene analysis reveals novel downstream PTEN and TNC genes required for drug-resistance and metastasis in lung cancer. Nucleic Acids Res 43: 1593-1608.
Tauler J, Zudaire E, Liu H, Shih J, Mulshine JL (2010). hnRNP A2/B1 modulates epithelial-mesenchymal transition in lung cancer cell lines. Cancer Res 70: 7137-7147.
Thakor N, Holcik M (2012). IRES-mediated translation of cellular messenger RNA operates in eIF2alpha- independent manner during stress. Nucleic Acids Res 40: 541-552.
Tockman MS, Mulshine JL, Piantadosi S, Erozan YS, Gupta PK, Ruckdeschel JC et al (1997). Prospective detection of preclinical lung cancer: results from two studies of heterogeneous nuclear ribonucleoprotein A2/B1 overexpression. Clin Cancer Res 3: 2237-2246.
Tominaga M, Sueoka N, Irie K, Iwanaga K, Tokunaga O, Hayashi S et al (2003). Detection and discrimination of preneoplastic and early stages of lung adenocarcinoma using hnRNP B1 combined with the cell cycle-related markers p16, cyclin D1, and Ki-67. Lung Cancer 40: 45-53.
Trisciuoglio D, Iervolino A, Candiloro A, Fibbi G, Fanciulli M, Zangemeister-Wittke U et al (2004). bcl-2 induction of urokinase plasminogen activator receptor expression in human cancer cells through Sp1 activation: involvement of ERK1/ERK2 activity. J Biol Chem 279: 6737-6745.
Tso PH, Wang Y, Yung LY, Tong Y, Lee MM, Wong YH (2013). RGS19 inhibits Ras signaling through Nm23H1/2-mediated phosphorylation of the kinase suppressor of Ras. Cell Signal 25: 1064-1074.
Tuteja N, Huang NW, Skopac D, Tuteja R, Hrvatic S, Zhang J et al (1995). Human DNA helicase IV is nucleolin, an RNA helicase modulated by phosphorylation. Gene 160: 143-148.
Van Der Kelen K, Beyaert R, Inze D, De Veylder L (2009). Translational control of eukaryotic gene expression. Crit Rev Biochem Mol Biol 44: 143-168.
Ventoso I, Sanz MA, Molina S, Berlanga JJ, Carrasco L, Esteban M (2006). Translational resistance of late alphavirus mRNA to eIF2alpha phosphorylation: a strategy to overcome the antiviral effect of protein kinase PKR. Genes Dev 20: 87-100.
Wang L, Guan X, Zhang J, Jia Z, Wei D, Li Q et al (2008a). Targeted inhibition of Sp1-mediated transcription for antiangiogenic therapy of metastatic human gastric cancer in orthotopic nude mouse models. Int J Oncol 33: 161-167.
Wang SA, Chuang JY, Yeh SH, Wang YT, Liu YW, Chang WC et al (2009). Heat shock protein 90 is important for Sp1 stability during mitosis. J Mol Biol 387: 1106-1119.
Wang SA, Li HY, Hsu TI, Chen SH, Wu CJ, Chang WC et al (2011a). Heat shock protein 90 stabilizes nucleolin to increase mRNA stability in mitosis. J Biol Chem 286: 43816-43829.
Wang YT, Chuang JY, Shen MR, Yang WB, Chang WC, Hung JJ (2008b). Sumoylation of specificity protein 1 augments its degradation by changing the localization and increasing the specificity protein 1 proteolytic process. J Mol Biol 380: 869-885.
Wang YT, Yang WB, Chang WC, Hung JJ (2011b). Interplay of posttranslational modifications in Sp1 mediates Sp1 stability during cell cycle progression. J Mol Biol 414: 1-14.
Wei S, Chuang HC, Tsai WC, Yang HC, Ho SR, Paterson AJ et al (2009). Thiazolidinediones mimic glucose starvation in facilitating Sp1 degradation through the up-regulation of beta-transducin repeat-containing protein. Mol Pharmacol 76: 47-57.
Xu J, Wang K, Zhang X, Qiu Y, Huang D, Li W et al (2010). HSP70: a promising target for laryngeal carcinoma radiaotherapy by inhibiting cleavage and degradation of nucleolin. J Exp Clin Cancer Res 29: 106.
Xu Y, Zhao F, Wang Z, Song Y, Luo Y, Zhang X et al (2012). MicroRNA-335 acts as a metastasis suppressor in gastric cancer by targeting Bcl-w and specificity protein 1. Oncogene 31: 1398-1407.
Yang HC, Chuang JY, Jeng WY, Liu CI, Wang AH, Lu PJ et al (2014a). Pin1-mediated Sp1 phosphorylation by CDK1 increases Sp1 stability and decreases its DNA-binding activity during mitosis. Nucleic Acids Res 42: 13573-13587.
Yang WB, Chen PH, Hsu Ts, Fu TF, Su WC, Liaw H et al (2014b). Sp1-mediated microRNA-182 expression regulates lung cancer progression. Oncotarget 5: 740-753.
Yeh SH, Yang WB, Gean PW, Hsu CY, Tseng JT, Su TP et al (2011). Translational and transcriptional control of Sp1 against ischaemia through a hydrogen peroxide-activated internal ribosomal entry site pathway. Nucleic Acids Res 39: 5412-5423.
Yin P, Zhao C, Li Z, Mei C, Yao W, Liu Y et al (2012). Sp1 is involved in regulation of cystathionine gamma-lyase gene expression and biological function by PI3K/Akt pathway in human hepatocellular carcinoma cell lines. Cell Signal 24: 1229-1240.
Yuan JH, Yang F, Chen BF, Lu Z, Huo XS, Zhou WP et al (2011). The histone deacetylase 4/SP1/microrna-200a regulatory network contributes to aberrant histone acetylation in hepatocellular carcinoma. Hepatology 54: 2025-2035.
Yue L, Li L, Liu F, Hu N, Zhang W, Bai X et al (2013). The oncoprotein HBXIP activates transcriptional coregulatory protein LMO4 via Sp1 to promote proliferation of breast cancer cells. Carcinogenesis 34: 927-935.