As a malignant tumor, HCC (hepatocellular carcinoma) is featured by a high recurrence rate with a poor prognosis. Increasing evidence supports an important role of lincRNAs in HCC. Here, the purpose of the study was to explore the function of LINC00978 (long non-coding RNA00978) in HCC and the underlying mechanisms. LINC00978 expression and its association with the progression of HCC were analyzed using HCC TCGA datasets. LINC00978 expression in tissues was measured using real-time PCR. Then, we knocked down LINC00978 in HCC cells to explore its effect on cellular invasion, proliferation, and migration. Finally, we investigated the potential molecular mechanism of LINC00978 by dual Luciferase reporter assay, FISH (fluorescence in situ hybridization) and RIP (RNA immunoprecipitation). LINC00978 expression was remarkably increased in HCC. A high level of LINC00978 was associated with poor prognosis of HCC. Additionally, LINC00978 silencing could repress the growth and metastasis of HCC cells. Mechanistically, it was revealed that LINC00978 could sponge microRNA-125b-5p and identified SOX12 (SRY-Box Transcription Factor 12) as a direct target gene of microRNA-125b-5p. More importantly, the suppressed effect of LINC00978 silencing on the metastasis and growth of HCC cells could be rescued by miR-125b-5p inhibition and overexpressed SOX12. LINC00978/microRNA-125b-5p/SOX12 axis promoted liver cancer migration, invasion, and proliferation, which could be used as a possible therapeutic target for the treatment of hepatocellular carcinoma.

Objective To explore functions of the histone H3 lysine 79 (K79) methyltransferase Dot1L in the development of pancreatic cancer and evaluate the possibility of targeting Dot1L to inhibit pancreatic cancer progression. Methods Patient samples were used to detect differences in Dot1L expression between tumor and adjacent tissues and to determine correlations between Dot1L expression in patients with different stages of pancreatic cancer. Lentiviral-mediated knockdown of Dot1L expression and flow cytometry were used to detect apoptosis in pancreatic cancer lacking Dot1L expression; chromatin immunoprecipitation and quantitative PCR were used to detect downstream target genes of Dot1L. Results We show that Dot1L is highly expressed in pancreatic cancer, and that its expression is related to pancreatic cancer stage. Knocking down Dot1L significantly promoted apoptosis in pancreatic cancer cells, while overexpressing Dot1L inhibited apoptosis. Mechanistically, Dot1L regulated apoptosis in pancreatic cancer cells by promoting NUPR1 expression. The enriched H3K79 trimethylation in the transcription initiation region of NUPR1 promoted its expression. Overexpressing NUPR1 inhibited the pancreatic cancer cell apoptosis caused by Dot1L knockdown. Conclusions Dot1L inhibits pancreatic cancer cell apoptosis by targeting NUPR1; thus, Dot1L is a promising target for pancreatic cancer treatment.