Long non-coding RNA TINCR suppresses metastatic melanoma dissemination by preventing ATF4 translation (2020)
Figure 3

Figure 3. Loss of TINCR expression promotes melanoma cell migration in vitro and tumor growth in in vivo by inducing a switch to an invasive phenotype.

A qRT-PCR quantification of TINCR RNA expression in MMC70 and WM902B cell lines, independently infected with two shRNA targeting TINCR expression (shTINCR-1 and -2). Cells transduced with shScamble (shSCR) were used as control. TINCR RNA levels relative to L32P housekeeping gene and control (mean±sd) measured in three independent biological experiments are shown. In both cell lines TINCR knockdown efficiency is more than 70% with the two shRNAs. Statistical analyses were performed using Student t -test (**: p<0.01).

B In vitro migration assay of MMC70 and WM902B cells transduced with shTINCR-1, shTINCR-2 or shSCR. Relative migration (mean±sd) from three independent experiments is indicated. Statistical analyses were performed using Student t -test (***: p<0.001).

C In vitro cell proliferation of shSCR or shTINCR infected MMC70 and WM902B cells assayed 72h after infection at the indicated time points using CellTiter-Glo luminescent kit (Promega). Cell growth from three biological replicates is indicated as proliferation rate relative to control cells (mean±sd). The difference between control and TINCR-silenced samples at all time points is not significant (Student t-test).

D Upper panel: in vivo growth of tumors derived from intradermal injection of shTINCR-2 or shSCR WM902B cells in NSG mice. 600,000 WM902B cells per mouse were inoculated. Tumor volumes (mean±sd) were measured 8 weeks after transplantation. Results from two independent experiments (four animals per group) are shown. Statistical analysis between control and TINCR-silenced groups was performed using the Student t -test (**=p<0.01). Lower panel: qRT-PCR analysis of TINCR RNA expression in tumors derived from in vivo transplant of shSCR and shTINCR WM902B cells (8 weeks after injection). TINCR RNA levels relative to L32P housekeeping gene and control (mean±sd) from four biological replicates (animals) from both experiments are shown.

E Drug-response curves showing increased resistance of shTINCR-WM902B cells after treatment with BRAF (Vemurafenib; from 10 to 10,000 nM) and MEK (Trametinib; from 4 to 2,000 nM) inhibitors. The shSCR- (control) and shTINCR-WM902B cells were treated with increasing concentrations of drugs and their viability assayed after 72 hours using CellTiter-Glo luminescent kit (Promega). Error bars represent s.e.m. of three biological replicates. The dose response curve was fit with nonlinear regression (GraphPad Prism).

F Gene ontology (GO) terms enrichment analysis of the differentially expressed genes identified by RNA-seq analysis in TINCR knockdown WM902B cells. All enrichments are significant at FDR<0.05.

G Western blot analysis of a panel of proteins that are specifically associated to the proliferative or invasive phenotype. Total protein lysates were extracted from shSCR- and shTINCR-WM902B cells (lane 1 and 2) or shSCR- and shTINCR-MMC70 cells (lane 3 and 4) 10 days after infection and analyzed by immunoblot assay using the indicated antibodies. Vinculin was used as loading control.