The function of long noncoding rnas in colorectal cancer

Maryam Taghavi narmi,1,* Samin abdolzadeh,2 Asiyeh jebelli,3

1. Department of Biological Science, Faculty of Basic Science, Higher Education Institute of Rab-Rashid , Tabriz , Iran
2. Department of Biological Science, Faculty of Basic Science, Higher Education Institute of Rab-Rashid , Tabriz , Iran
3. Department of Biological Science, Faculty of Basic Science, Higher Education Institute of Rab-Rashid , Tabriz , Iran

Abstract

Introduction

Colorectal cancer (crc) is the main cause of cancer mortality worldwide. its poor prognosis is mainly ascribed to high recurrence rates. various genetics factors are associated with development of crc. long noncoding rnas (lncrnas) constitute one of the largest classes of transcripts with >200 nucleotides in length that do not encode for proteins. lncrnas act as an essential regulator in almost every aspect of biology. they interact with dna, rna, protein molecules and/or their combinations, acting as an essential regulator in chromatin organization, and transcriptional and post transcriptional regulation. lncrnas have been widely implicated in various diseases such as cancer.

Methods

increasing evidence suggests that several lncrnas are dysregulated and play critical roles for tumor initiation, growth, and metastasis in tumorigenesis. lncrnas can be regulated by key oncogenes and tumor suppressors, adding complexity to the intricate crosstalk between protein coding genes and the noncoding transcriptome. therefore, lncrnas serve as a promising target for cancer diagnosis and therapy. different lncrnas have been discovered that affect crc formation. the lncrna small nucleolar rna host gene 1 (snhg1), for example, contributes to the promotion of tumor development. however, the connections between snhg1 and crc are still unclear.

Results

Snhg7 with a length of 2176 base pairs is another one of the recognized lncrnas which is located on chromosome 9q34.3. snhg7 inhibits apoptosis and promotes the proliferation, migration, and invasion in many cancers. the lncrna h19 has been identified as an oncogenic gene and elevated expression of h19 is tightly linked to tumorigenesis and progression of multiple cancer types including crc. in addition to high expression of h19 in primary crc tissues, it provides a role as a novel regulator of epithelial to mesenchymal transition (emt) in crc. h19 is also associated with the stemness of colorectal cancer stem cells in crc specimens.

Conclusion

Overexpressed in colon carcinoma-1 (occ-1), another main lncrna, is one of the earliest annotated lncrnas in crc. however, its function remains largely unknown. occ-1 knockdown by rna interference promotes cell growth both in vitro and in vivo, which is largely due to its ability to inhibit g0 to g1 and g1 to s phase cell cycle transitions. in addition, overexpression of occ-1 can suppress cell growth in occ-1 knockdown cells. lncrna occ-1 can regulate the levels of a large number of mrnas at post-transcriptional level through modulating rna binding protein stability of hur. emerging evidence indicates the effect of lncrna plasmacytoma variant translocation 1 (pvt1) in tumourigenesis of crc. however, its specific function on the proliferation, invasion and metastasis of crc are still poorly understood. in summary, the innovations in rna-sequence technologies and computational biology could identify lncrnas at a rapid pace and introduce them as a candidate targets for crc diagnosis and therapy.

Keywords

Lncrna, snhgs, h19, occ-1, pvt1