Let-7c Inhibits NSCLC Cell Proliferation by Targeting HOXA1

  • Zhan, Min (Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University) ;
  • Qu, Qiang (Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University) ;
  • Wang, Guo (Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University) ;
  • Liu, Ying-Zi (Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University) ;
  • Tan, Sheng-Lan (Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University) ;
  • Lou, Xiao-Ya (Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University) ;
  • Yu, Jing (Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University) ;
  • Zhou, Hong-Hao (Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University)
  • Published : 2013.01.31


Objective: The aim of the present study was to explore mechanisms by which let-7c suppresses NSCLC cell proliferation. Methods: The expression level of let-7c was quantified by qRT-PCR. A549 and H1299 cells were transfected with let-7c mimics to restore the expression of let-7c. The effects of let-7c were then assessed by cell proliferation, colony formation and cell cycle assay. Mouse experiments were used to confirm the effect of let-7c on tumorigenicity in vivo. Luciferase reporter assays and Western blotting were performed to identify target genes for let-7c. Results: HOXA1 was identified as a novel target of let-7c. MTS, colony formation and flow cytometry assays demonstrated that forced expression of let-7c inhibited NSCLC cell proliferation by inducing G1 arrest in vitro, consistent with inhibitory effects induced by knockdown of HOXA1. Mouse experiments demonstrated that let-7c expression suppressed tumorigenesis. Furthermore, we found that let-7c could regulate the expression of HOXA1 downstream effectors CCND1, CDC25A and CDK2. Conclusions: Collectively, these results demonstrate let-7c inhibits NSCLC cell proliferation and tumorigenesis by partial direct targeting of the HOXA1 pathway, which suggests that restoration of let-7c expression may thus offer a potential therapeutic intervention strategy for NSCLC.



Supported by : National Natural Science Foundation of China


  1. Pasquinelli AE, Reinhart BJ, Slack F, et al (2000). Conservation of the sequence and temporal expression of let-7 heterochronic regulatory RNA. Nature, 408, 86-9.
  2. Pelosi A, Careccia S, Lulli V, et al (2012). miRNA let-7c promotes granulocytic differentiation in acute myeloid leukemia. Oncogene.
  3. Roush S, Slack FJ (2008). The let-7 family of microRNAs. Trends Cell Biol, 18, 505-16.
  4. Schultz J, Lorenz P, Gross G, et al (2008). MicroRNA let-7b targets important cell cycle molecules in malignant melanoma cells and interferes with anchorage-independent growth. Cell Res, 18, 549-57.
  5. Shimizu S, Takehara T, Hikita H, et al (2010). The let-7 family of microRNAs inhibits Bcl-xL expression and potentiates sorafenib-induced apoptosis in human hepatocellular carcinoma. J Hepatol, 52, 698-704.
  6. Simoncini T, Hafezi-Moghadam A, Brazil DP, et al (2000). Interaction of oestrogen receptor with the regulatory subunit of phosphatidylinositol-3-OH kinase. Nature, 407, 538-41.
  7. Suzuki R, Takemura K, Tsutsumi M, et al (2001). Detection of cyclin D1 overexpression by real-time reverse-transcriptase-mediated quantitative polymerase chain reaction for the diagnosis of mantle cell lymphoma. Am J Pathol, 159, 425-9.
  8. Takamizawa J, Konishi H, Yanagisawa K, et al (2004). Reduced expression of the let-7 microRNAs in human lung cancers in association with shortened postoperative survival. Cancer Res, 64, 3753-6.
  9. Wang M, Wu L, Wang L, et al (2010). Down-regulation of Notch1 by gamma-secretase inhibition contributes to cell growth inhibition and apoptosis in ovarian cancer cells A2780. Biochem Biophys Res Commun, 393, 144-9.
  10. Yamada H, Yanagisawa K, Tokumaru S, et al (2008). Detailed characterization of a homozygously deleted region corresponding to a candidate tumor suppressor locus at 21q11-21 in human lung cancer. Genes Chromosomes Cancer, 47, 810-8.
  11. Yin R, Bao W, Xing Y, et al (2012). MiR-19b-1 inhibits angiogenesis by blocking cell cycle progression of endothelial cells. Biochem Biophys Res Commun, 417, 771-6.
  12. Zha TZ, Hu BS, Yu HF, et al (2012). Overexpression of HOXA1 correlates with poor prognosis in patients with hepatocellular carcinoma. Tumour Biol, 33, 2125-34.
  13. Zhu T, Starling-Emerald B, Zhang X, et al (2005). Oncogenic transformation of human mammary epithelial cells by autocrine human growth hormone. Cancer Res, 65, 317-24.
  14. Cho HS, Toyokawa G, Daigo Y, et al (2012). The JmjC domain-containing histone demethylase KDM3A is a positive regulator of the G1/S transition in cancer cells via transcriptional regulation of the HOXA1 gene. Int J Cancer, 131, E179-89.
  15. Esquela-Kerscher A, Trang P, Wiggins JF, et al (2008). The let-7 microRNA reduces tumor growth in mouse models of lung cancer. Cell Cycle, 7, 759-64.
  16. Feng X, Wu Z, Wu Y, et al (2011). Cdc25A regulates matrix metalloprotease 1 through Foxo1 and mediates metastasis of breast cancer cells. Mol Cell Biol, 31, 3457-71.
  17. Gong FX, Xia JL, Yang BW, et al (2011). Effect of let-7c on the proliferation of human hepatocellular carcinoma cell HCCLM3. Zhonghua Gan Zang Bing Za Zhi, 19, 853-6.
  18. Han HB, Gu J, Zuo HJ, et al (2012). Let-7c functions as a metastasis suppressor by targeting MMP11 and PBX3 in colorectal cancer. J Pathol, 226, 544-55.
  19. Jemal A, Siegel R, Ward E, et al (2007). Cancer statistics, 2007. CA Cancer J Clin, 57, 43-66.
  20. Jinno S, Suto K, Nagata A, et al (1994). Cdc25A is a novel phosphatase functioning early in the cell cycle. EMBO J, 13, 1549-56.
  21. Johnson CD, Esquela-Kerscher A, Stefani G, et al (2007). The let-7 microRNA represses cell proliferation pathways in human cells. Cancer Res, 67, 7713-22.
  22. Johnson SM, Grosshans H, Shingara J, et al (2005). RAS is regulated by the let-7 microRNA family. Cell, 120, 635-47.
  23. Kim HH, Kuwano Y, Srikantan S, et al (2009). HuR recruits let-7/RISC to repress c-Myc expression. Genes Dev, 23, 1743-8.
  24. Kumar MS, Erkeland SJ, Pester RE, et al (2008). Suppression of non-small cell lung tumor development by the let-7 microRNA family. Proc Natl Acad Sci U S A, 105, 3903-8.
  25. Liu Q, Fu H, Sun F, et al (2008). miR-16 family induces cell cycle arrest by regulating multiple cell cycle genes. Nucleic Acids Res, 36, 5391-404.
  26. Mayr C, Hemann MT, Bartel DP. (2007). Disrupting the pairing between let-7 and Hmga2 enhances oncogenic transformation. Science, 315, 1576-9.
  27. Mohankumar KM, Xu XQ, Zhu T, et al (2007). HOXA1-stimulated oncogenicity is mediated by selective upregulation of components of the p44/42 MAP kinase pathway in human mammary carcinoma cells. Oncogene, 26, 3998-4008.
  28. Nadiminty N, Tummala R, Lou W, et al (2012). MicroRNA let-7c is downregulated in prostate cancer and suppresses prostate cancer growth. PLoS One, 7, e32832.
  29. Navarro A, Marrades RM, Vinolas N, et al (2009). MicroRNAs expressed during lung cancer development are expressed in human pseudoglandular lung embryogenesis. Oncology-Basel, 76, 162-9.
  30. Ohuchida K, Mizumoto K, Lin C, et al (2012). MicroRNA-10a is overexpressed in human pancreatic cancer and involved in its invasiveness partially via suppression of the HOXA1 gene. Ann Surg Oncol, 19, 2394-402.
  31. Abe M, Hamada J, Takahashi O, et al (2006). Disordered expression of HOX genes in human non-small cell lung cancer. Oncol Rep, 15, 797-802.
  32. Aleem E, Kiyokawa H, Kaldis P (2005). Cdc2-cyclin E complexes regulate the G1/S phase transition. Nat Cell Biol, 7, 831-6.
  33. Barh D, Malhotra R, Ravi B, et al (2010). MicroRNA let-7: an emerging next-generation cancer therapeutic. Curr Oncol, 17, 70-80.
  34. Bartel DP (2004). MicroRNAs: genomics, biogenesis, mechanism, and function. Cell, 116, 281-97.
  35. Bitu CC, Destro MF, Carrera M, et al (2012). HOXA1 is overexpressed in oral squamous cell carcinomas and its expression is correlated with poor prognosis. BMC Cancer, 12, 146.
  36. Chariot A, Castronovo V. (1996). Detection of HOXA1 expression in human breast cancer. Biochem Biophys Res Commun, 222, 292-7.
  37. Chen H, Sukumar S (2003). Role of homeobox genes in normal mammary gland development and breast tumorigenesis. J Mammary Gland Biol Neoplasia, 8, 159-75.

Cited by

  1. Expression profile of microRNAs in gastrointestinal stromal tumors revealed by high throughput quantitative RT-PCR microarray vol.21, pp.19, 2015,
  2. HOXA1 enhances the cell proliferation, invasion and metastasis of prostate cancer cells vol.34, pp.3, 2015,
  3. JMJD1A promotes tumorigenesis and forms a feedback loop with EZH2/let-7c in NSCLC cells vol.37, pp.8, 2016,
  4. through retinoic acid response elements in acute myeloid leukemia vol.59, pp.1, 2018,