RGS20 promotes non-small cell lung carcinoma proliferation via autophagy activation and inhibition of the PKA-Hippo signaling pathway

BACKGROUND

Novel therapeutic targets are urgently needed for treating drug-resistant non-small cell lung cancer (NSCLC) and overcoming drug resistance to molecular-targeted therapies. Regulator of G protein signaling 20 (RGS20) is identified as an upregulated factor in many cancers, yet its specific role and the mechanism through which RGS20 functions in NSCLC remain unclear. Our study aimed to identify the role of RGS20 in NSCLC prognosis and delineate associated cellular and molecular pathways.

METHODS

Immunohistochemistry and lung cancer tissue microarray were used to verify the expression of RGS20 between NSCLC patients. CCK8 and cell cloning were conducted to determine the proliferation ability of H1299 and Anip973 cells in vitro. Furthermore, Transcriptome sequencing was performed to show enrichment genes and pathways. Immunofluorescence was used to detect the translocation changes of YAP to nucleus. Western blotting demonstrated different expressions of autophagy and the Hippo-PKA signal pathway. In vitro and in vivo experiments verified whether overexpression of RGS20 affect the proliferation and autophagy of NSCLC through regulating the Hippo pathway.

RESULTS

The higher RGS20 expression was found to be significantly correlated with a poorer five-year survival rate. Further, RGS20 accelerated cell proliferation by increasing autophagy. Transcriptomic sequencing suggested the involvement of the Hippo signaling pathway in the action of RGS20 in NSCLC. RGS20 activation reduced YAP phosphorylation and facilitated its nuclear translocation. Remarkably, inhibiting Hippo signaling with GA-017 promoted cell proliferation and activated autophagy in RGS20 knock-down cells. However, forskolin, a GPCR activator, increased YAP phosphorylation and reversed the promoting effect of RGS20 in RGS20-overexpressing cells. Lastly, in vivo experiments further confirmed role of RGS20 in aggravating tumorigenicity, as its overexpression increased NSCLC cell proliferation.

CONCLUSION

Our findings indicate that RGS20 drives NSCLC cell proliferation by triggering autophagy via the inhibition of PKA-Hippo signaling. These insights support the role of RGS20 as a promising novel molecular marker and a target for future targeted therapies in lung cancer treatment.

Regulator of G protein signaling 20 promotes proliferation and migration in bladder cancer via NF-κB signaling

BACKGROUND

Bladder cancer is a complicated disease with high rate of morbidity and mortality, in which proliferation and migration are both well acknowledged as aggressive phenotypes of bladder cancer cells. A better understanding of the mechanisms of tumor proliferation and migration would provide an insight into cancer progression and provide effective therapeutic strategies.

METHODS

The expression of RGS20 was detected using qRT-PCR,western blotting and immunohistochemistry. MTT, Colony formation, anchorage-independent growth assay, and transwell assay were used to evaluate the pro-proliferation and pro-migration potential of RGS20 in vitro. Tumor growth was monitored and analyzed in an animal model. Luciferase activity assay, nuclear extract analysis, and multiple blockade of NF-κB were used to evaluate NF-κB signaling activity.

RESULTS

It revealed that RGS20 was significantly upregulated in bladder cancer and increased RGS20 expression correlated significantly with worse 5-year overall survival. Ectopic overexpression of RGS20 accelerated the proliferation and migration of bladder cancer cells, whereas knockdown of RGS20 inhibited these effects. Mechanistically, RGS20 could activate NF-κB signaling, which played a crucial role in RGS20's effects on proliferation, migration, and tumorigenicity of bladder cancer cells.

CONCLUSION

Our study highlights that RGS20 acted as an oncogene in bladder cancer and a better understanding of RGS20's functions might provide the potential for clinical intervention in this disease.

A disease-associated mutation in the adhesion GPCR BAI2 (ADGRB2) increases receptor signaling activity

Mutations in G protein-coupled receptors (GPCRs) that increase constitutive signaling activity can cause human disease. A de novo C-terminal mutation (R1465W) in the adhesion GPCR BAI2 (also known as ADGRB2) was identified in a patient suffering from progressive spastic paraparesis and other neurological symptoms. In vitro studies revealed that this mutation strongly increases the constitutive signaling activity of an N-terminally cleaved form of BAI2, which represents the activated form of the receptor. Further studies dissecting the mechanism(s) underling this effect revealed that wild-type BAI2 primarily couples to Gα_z , with the R1465W mutation conferring increased coupling to Gα_i . The R1465W mutation also increases the total and surface expression of BAI2. The mutation has no effect on receptor binding to β-arrestins, but does perturb binding to the endocytic protein endophilin A1, identified here as a novel interacting partner for BAI2. These studies provide new insights into the signaling capabilities of the adhesion GPCR BAI2/ADGRB2 and shed light on how an apparent gain-of-function mutation to the receptor's C-terminus may lead to human disease.

Regulator of G protein signaling 20 correlates with clinicopathological features and prognosis in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a highly aggressive tumor subtype lacking effective prognostic indicators or therapeutic targets. Therefore, finding a novel molecular biomarker for TNBC to achieve target therapy and predict its prognosis is crucial in preventing inappropriate treatment. Regulator of G-protein signaling (RGS) families of protein can negatively regulate signaling of heterotrimeric G proteins and are known to be upregulated in various tumors. In this study, we demonstrated that RGS20 was more highly expressed in TNBC tumor tissue than in adjacent normal tissue by analyzing the cancer genome atlas (TCGA) database. However, RGS20 expression was low in all breast cancer and luminal breast cancer patients. Validated by the TCGA cohort, RGS20 was upregulated in lymph node-positive TNBC compared with that in lymph node-negative breast cancer. High expression of RGS20 had a risk of lymph node metastasis, ki-67 > 14%, poor N stage, and poor clinical stage in the immunohistochemistry of tissue microarrays. Moreover, K-M plot analysis showed that TNBC patients with high RGS20 expression had poor relapse-free survival. In summary, the findings revealed that RGS20 was a special TNBC oncogene that promoted tumor progression and influenced TNBC prognosis. This study is the first to show that RGS20 was a special oncogene, and its high expression was significantly associated with the progression and prognosis of TNBC. RGS20 may be a novel molecular biomarker for the targeted therapy and prognosis of TNBC.

Regulator of G protein signaling 20 enhances cancer cell aggregation, migration, invasion and adhesion

Several RGS (regulator of G protein signaling) proteins are known to be upregulated in a variety of tumors but their roles in modulating tumorigenesis remain undefined. Since the expression of RGS20 is elevated in metastatic melanoma and breast tumors, we examined the effects of RGS20 overexpression and knockdown on the cell mobility and adhesive properties of different human cancer cell lines, including cervical cancer HeLa, breast adenocarcinoma MDA-MB-231, and non-small cell lung carcinoma H1299 and A549 cells. Expression of RGS20 enhanced cell aggregation, migration, invasion and adhesion as determined by hanging drop aggregation, wound healing, transwell chamber migration and invasion assays. Conversely, shRNA-mediated knockdown of endogenous RGS20 impaired these responses. In addition, RGS20 elevated the expression of vimentin (a mesenchymal cell marker) but down-regulated the expression of E-cadherin, two indicators commonly associated with metastasis. These results suggest that the expression of RGS20 may promote metastasis of tumor cells.