RP11-350G8.5 putative oncogenic role: in vitro validation and preliminary data from in vivo models. (A) Flow cytometric monitoring of GFP expression in ABZB cells transduced with a SCRAMBLE-GFP-CRISPR negative control vector, an RPL8/KO-GFP-CRISPR positive control vector (selected from Project Score [37]), and 2 GFP-CRISPR constructs encoding for 2 pgRNAs targeting RP11-350G8.5. Gray curves represent the percentage of viable cells at day 0 (48 hours after lentiviral transduction), while colored curves represent the percentage of viable cells at day 20. Bars on the right represent the fold change in percentage of GFP-expressing cells 20 days after target depletion against day 0. (B) Evaluation of IL-6R RNA expression level through quantitative real time PCR (qRT-PCR) on ABZB after transduction with SCRAMBLE vector or KO of RP11-350G8.5 with pgRNA#1 or pgRNA#2 or with a vector overexpressing RP11-350G8.5 (UP). (Data are normalized to the expression of GAPDH.) Statistics were obtained using multiple t-tests, resulting in no significant (ns) differences, as per the reported P values. (C) Flow cytometric monitoring of GFP in JJN.3 and NCI-H929 MM transduced cells, and percentage of GFP-positive cells is reported by overlapping curves referred to day 20 (colored curves) against day 0 (light gray curves). (D) Validation of RP11-350G8.5 KO in nontumoral cells, performed as described for A and C. (E) Representative images of RNA-FISH analysis. Nuclei are counterstained with DAPI (blue signal), whereas C3-fluorescein–conjugated GAPDH (green signal) has been used as cytoplasmic marker. Customly designed Stellaris probes targeting RP11-350G8.5 have been conjugated with 5-carboxytetramethylrhodamine (TAMRA) dye (red signal). Representative pictures acquired with a DMI6000-AF6000 Leica (Wetzlar, Germany) fluorescence microscope at magnification ×63 are reported, followed by specific regions of interest (ROIs), which are represented as enlarged images. (F) Dose-response curves 24 hours after treatment with bortezomib in AMO-1 cells overexpressing RP11-350G8.5 (1-10 nM). Statistics were analyzed using multiple t-tests (cutoff ∗P < .05, ∗∗P < .01). (G) In vivo imaging of engrafted ABZB cells. A total of 5 × 10⁶ ABZB cells, which previously underwent highly efficient transduction (multiplicity of infection = 1) of RP11-350G8.5 KO-GFP or the SCRAMBLE vectors, were subcutaneously inoculated in mice (n = 2 per group). Images of tumors were acquired when the tumoral masses became palpable (identified as DAY 1), and at the end of the experiment (DAY 16, when tumors reached 2 cm in diameter). Both DAY 1 and DAY 16 were set up by considering SCRAMBLE mice, because SCRAMBLE cells have been faster to generate tumoral masses, due to their higher proliferative rate, and to grow up to 2 cm in diameter, with respect to KO cells. Tumors appear as yellow high-density signals on the right flank of the mice. Pictures were obtained with the IVIS (Perkin Elmer) system. (H) Tumor growth as mean measurement ± standard deviation (SD) across mice groups (n = 2). (I) Photographs of excised tumors were captured by a digital camera. (J) Weights of excised tumors, reported as mean ± SD across mice groups. Statistics were analyzed using multiple t-tests (cutoff: ∗P < .05).