The long non-coding RNA AK023948 enhances tumor progression in hepatocellular carcinoma

Abstract

The long non-coding RNAs (lncRNAs) have been demonstrated to play pivotal roles in a broad range of processes including tumor biology. However, the exact contributions of lncRNAs to hepatocellular carcinoma (HCC) remain poorly defined. In current study, we have unraveled a novel function of AK023948 in HCC. We found that AK023948 was substantially upregulated in tumor tissues. Meanwhile, higher AK023948 expression correlated with poor survival. Upregulation of AK023948 expression can promote HepG2 and Hep3B proliferation and invasion in in vitro experiments. Furthermore, AK023948 also decreased tumor growth in vivo. The tumorigenic role of AK023948 was partially ascribed to PI3K/Akt/mTOR signaling and AK023948 knockdown decreased pathway activation and tumor growth. These data collectively suggest an oncogenic role for AK023948 and may provide potential insight into therapeutic intervention.

Keywords: AK023948; HCC; PI3K/Akt/mTOR; lncRNA.

Figure 1.

The lncRNA AK023948 was upregulated in hepatocellular carcinoma (HCC). (A) qPCR results for 79 HCC samples as well as corresponding normal adjacent tissues (NATs). (B) Expression of AK023948 in normal cell line CL-48 and 5 HCC cell lines. **P<0.01. (C) Quantification of AK023948 expression in 79 HCC samples. The cut-off value was determined as indicated. 51 samples were identified as high expression (white bars).

Figure 2.

Kaplan-Meier survival curves for hepatocellular carcinoma (HCC) patients. HCC patients with high AK023948 expression had a significantly shorter overall survival (P<0.01, log-rank test).

Figure 3.

AK023948 can promote hepatocellular carcinoma (HCC) progression. The relative knockdown efficiency for (A) HepG2 and (B) Hep3B cells were shown. The si #3 showed the highest efficiency. The transfection verification using pcDNA-AK023948 was determined in (C) HepG2 and (D) Hep3B cells. (E) A 5-day proliferation assay for HepG2 (left) and Hep3B (right) cells left untreated or transfected with empty vector, pcDNA-AK023948 or si-AK023948. (F) Invasion assays for HepG2 (top) and Hep3B (bottom) cells were displayed in groups either untreated or transfected with empty vector, pcDNA-AK023948 or si-AK023948.

Figure 4.

AK023948 can affect PI3K pathway. (A) Western blot for PI3K/Akt/mTOR signaling pathway using specific antibodies. NC, negative control; KD, si-AK023948. The association between relative expression of AK023948 and activated (B) PI3K, (C) Akt and (D) mTOR for 79 specimens were shown. Pearson correlation coefficients were marked. All P-values <0.0001. (E) The growth of solid tumors in nude mice injected with HepG2 cells either untreated or transfected with si-AK023948, n=6 for each case. The median levels were indicated. (F) Tumor size after 30 days' implantation, n=6 for each group. The median levels were shown. (G) Immunostaining for intrinsic AK023948 levels in hepatocellular carcinoma (HCC) samples and normal adjacent tissues (NATs).