NBL-S

HCP5 could Promote the Proliferation of Neuroblastoma Cells

Among pediatric patients, neuroblastoma represents the most frequently occurring solid tumor. Research indicated that long-chain noncoding RNA (lncRNA) HCP5 played a key role in tumor development yet its specific function in NB was not yet determined. Zhu's team plans to investigate HCP5's function in NB and identify its molecular mechanism.

HCP5 expression levels in neuroblastoma tissues exceeded those in paracancerous tissues as demonstrated by RT-PCR results (Fig. 1 A). SHSY-5Y and Kelly cells with elevated HCP5 expression demonstrated superior clone formation abilities compared to NBL-S and SK-N-AS cells which exhibited lower HCP5 expression levels (Fig. 1B–D). In SHSY-5Y cells with high HCP5 expression level, the cell viability (Fig. 2A), clone forming (Fig. 2C and G) and DNA synthesis ability (Fig. 2E and H) significantly decreased after down regulating HCP5 expression. After reducing HCP5 expression there was a marked decrease in DNA synthesis ability (Fig. 2E and H). NBL-S cells that express low levels of HCP5 showed increased cell viability (Fig. 2B), Clone forming ability (Fig. 2D and I) and DNA synthesis (Fig. 2F and J) HCP5 expression upregulation produced a marked increase in 2F and J measurements.

Fig. 1. The expression level of HCP5 in neuroblastoma was up-regulated and related to cell proliferation (Zhu K, Wang L, et al., 2021).

Fig. 2. HCP5 promoted the proliferation of neuroblastoma cells (Zhu K, Wang L, et al., 2021).

PI3K Activation in Neuroblastoma Cells is Predominantly Mediated by p110α but not by p110β or p110δ

Neuroblastoma exhibits high heterogeneity and frequent relapses, challenging conventional treatments. Molecular targeting is seen as a viable alternative. In this study, the role of the PI3K isoform p110α, prevalent in neuroblastoma growth, was studied through in vitro and in vivo experiments.

They utilized the R2: Genomics Analysis and Visualization Platform to examine the expression of class IA PI3K isoforms in neuroblastoma and found that elevated PIK3CA expression correlates with poor prognosis and advanced disease stages. In addition to the differential correlation of class IA PI3K isoforms with neuroblastoma patient outcomes, we tried to determine the isoform dependence of neuroblastoma to PI3Ks. The efficacy of PI3K inhibitors with distinct isoform specificity was compared in neuroblastoma cells (Fig. 3a). The study included cell lines with genetic alterations in MYCN and ALK. Five MYCN-amplified cell lines (LA1-5S, IMR-32, BE(2)C, LAN-5, KELLY) and three non-amplified lines (SH-SY5Y, NBL-S, SK-N-AS) were tested for cytotoxicity by class IA PI3K inhibitors. SH-SY5Y and KELLY have the ALKF1174L mutation, LAN-5 has ALKR1275Q, while LA1-5s lacks ALK expression. We confirmed the expression levels of ALK and MYCN in these lines to understand gene variation. MYCN shows high expression in LAN-5, KELLY, BE(2)C, and IMR-32, and ALK is highly expressed in LAN-5, IMR-32, KELLY, NBL-S, and SH-SY5Y. They found that copanlisib effectively reduced the viability of all tested neuroblastoma cell lines (Fig. 3b). With IC50 values under 1 µM, it was the most effective of the three p110α inhibitors. The pan-PI3K inhibitor pictilisib was also cytotoxic but less effective than copanlisib, hindered by poor solubility in some lines (Fig. 3c). Alpelisib, a p110α-selective inhibitor, reduced cell viability at less than 5 μM (Fig. 3d). Conversely, p110β inhibitor TGX-221 and p110δ inhibitor idelalisib did not affect cell proliferation below 10 μM (Fig. 3e, f), indicating neuroblastoma cells rely on p110α for growth.

Fig. 3. p110α inhibitors decrease the viability of neuroblastoma cells (Guo Y, Guo D H, et al., 2022).