# Targeting oncogenic NTSR1 with liensinine reprograms Gq-mediated signaling to suppress lung adenocarcinoma

## TL;DR

Liensinine, a natural compound, inhibits the NTSR1 receptor in lung cancer cells, reducing tumor growth and altering harmful signaling pathways.

## Contribution

Liensinine is identified as a novel NTSR1 antagonist that selectively inhibits Gq signaling and reprograms transcriptional pathways in lung adenocarcinoma.

## Key findings

- NTSR1 is overexpressed in LUAD and linked to poor prognosis, immune remodeling, and advanced tumor stage.
- Liensinine selectively inhibits NTSR1-Gq signaling, reduces cell proliferation, and induces apoptosis in LUAD cell lines.
- Transcriptomic analysis shows liensinine reverses pro-oncogenic pathways and activates protective pathways like steroid biosynthesis.

## Abstract

Lung adenocarcinoma (LUAD) is a leading cause of cancer death. Neurotensin receptor 1 (NTSR1), a G protein-coupled receptor, is overexpressed in LUAD and linked to poor prognosis, but its therapeutic potential is underexplored.

This study combined multi-database bioinformatics to systematically evaluate the expression, prognostic relevance, genetic alterations, and immune-microenvironment association of NTSR1 across cancer types. The ONE-GO biosensor, SPR, PRESTO-Tango, and in-cell ELISA assays was used to confirm that liensinine specifically inhibits NTSR1-mediated G-protein signaling. Functional consequences of NTSR1 depletion and liensinine treatment—including effects on proliferation, apoptosis, and global transcription—were examined in vitro via CCK-8, flow cytometry, RNA-seq and Western blot. Key findings were validated by RT-qPCR in cellular models and further supported using LUAD patient cohorts from the UALCAN platform.

Bioinformatics analysis confirmed significant upregulation of NTSR1 in LUAD, and its high expression was closely associated with advanced tumor stage, remodeled immune microenvironment, and poor overall patient survival. ONE-GO profiling revealed preferential coupling of NTSR1 to Gαq. Liensinine bound NTSR1 with micromolar affinity and selectively inhibited NTSR1‑mediated Gq signaling while sparing β‑arrestin recruitment and agonist-induced internalization. Functional experiments demonstrated that either NTSR1 knockdown or liensinine treatment significantly inhibited A549 cell proliferation and migration while inducing apoptosis, with the effect of liensinine being dependent on NTSR1 presence. These findings were consistently validated in HCI‑H1299, HCI‑H1975, and PC‑9 cell lines. Transcriptomic analysis revealed that NTSR1 overexpression enriched pro-oncogenic pathways such as neuroactive ligand-receptor interaction and calcium signaling. In contrast, liensinine treatment reversed these alterations and shifted the transcriptional program toward pathways including steroid biosynthesis and protein processing in the endoplasmic reticulum. Western blot analysis has further confirmed that liensinine reduced the phosphorylation of PKC and ERK guided by NTS/NTSR1. Furthermore, we identified a core gene signature comprising PTGS2, SPR1, ABCG1, and ABCA1, whose expression was synergistically regulated by NTSR1 and liensinine and demonstrated prognostic value in LUAD patients.

NTSR1 is a key oncogenic driver in LUAD. Liensinine is a novel NTSR1 antagonist that suppresses tumors by selectively inhibiting Gq signaling and reprogramming the transcriptional landscape.