A micro-peptide encoded by HOXB-AS3 promotes the proliferation and viability of oral squamous cell carcinoma cell lines by directly binding with IGF2BP2 to stabilize c-Myc

HOXB-AS3 is a long non-coding RNA and recent studies have shown that the HOXB-AS3-encoded micro-peptide was associated with the progression of colon cancer tumorigenesis; however, the biofunction of HOXB-AS3 varies in different types of cancer and the potential function in oral squamous cell carcinoma (OSCC) is still unknown. The Cancer Genome Atlas (TCGA) database was searched and the expression patterns of HOXB-AS3 in head and neck carcinoma were analyzed. Reverse transcription-quantitative PCR and western blot analysis was used to measure the mRNA and protein expression level of HOXB-AS3 in patients with OSCC, respectively. Next, HOXB-AS3 was knocked down in 2 OSCC cell lines to investigate the biological function of the HOXB-AS3-encoded protein using a Cell Counting Kit-8 and colony formation assays. To further identify the potential mechanism of the HOXB-AS3-encoded protein, co-immunoprecipitation was also used to detect the interaction between HOXB-AS3 and IGF2BP2, while HOXB-AS3 was re-expressed to determine whether the HOXB-AS3-encoded protein and not HOXB-AS3 exerted its function in OSCC. HOXB-AS3 was upregulated in OSCC tissues, in both TCGA database and in patients with OSCC recruited into the present study. HOXB-AS3 was associated with poor prognosis in OSCC. The proliferation and viability decreased in the 2 OSCC cell lines following knock down of HOXB-AS3. HOXB-AS3 was also found to encode a protein that directly interacted with IGF2BP2 and thereby promoted the stability of c-myc. Taken together, the results from the present study indicated that increased HOXB-AS3 expression was associated with poor prognosis in OSCC. This indicated that HOXB-AS3 and its encoded protein promoted OSCC cell proliferation and viability by maintaining c-Myc mRNA stability by directly binding to IGF2BP2.