Pre-clinical phaeochromocytoma and paraganglioma models: Cell lines, animal models, and a human primary culture model.

While the establishment of human phaeochromocytoma and paraganglioma (PPGL) cell lines has proven to be particularly difficult over several decades of research, there are other reliable pre-clinical PPGL models currently available. This review provides a summary of these models, together with our recently established personalised drug screening platform using patient-derived PPGL primary cultures. Such currently available PPGL models include murine and rat PPGL cell lines, of which only one cell line (PC12) is publicly accessible through a cell repository, and PPGL animal models, of which the patient-derived xenograft models are promising but complex to establish. We have developed next-generation implementation of human PPGL primary cultures, enabling reliable and personalised drug screening and an individualised analysis of tumour drug responsivity based on the tumour's unique genetic, biochemical, immunohistochemical and clinical profile. Overall, reliable PPGL models, including patient-derived primary culture models, are essential to advance pre-clinical research in the field of PPGLs.

Zona Glomerulosa-Derived Klotho Modulates Aldosterone Synthase Expression in Young Female Mice.

Klotho plays a critical role in the regulation of ion and fluid homeostasis. A previous study reported that haplo-insufficiency of Klotho in mice results in increased aldosterone synthase (CYP11B2) expression, elevated plasma aldosterone, and high blood pressure. This phenotype was presumed to be the result of diminished Klotho expression in zona glomerulosa (zG) cells of the adrenal cortex; however, systemic effects on adrenal aldosterone production could not be ruled out. To examine whether Klotho expressed in the zG is indeed a critical regulator of aldosterone synthesis, we generated a tamoxifen-inducible, zG-specific mouse model of Klotho deficiency by crossing Klotho-flox mice with Cyp11b2-CreERT mice (zG-Kl-KO). Tamoxifen-treated Cyp11b2-CreERT animals (zG-Cre) served as controls. Rosa26-mTmG reporter mice were used for Cre-dependent lineage-marking. Two weeks after tamoxifen induction, the specificity of the zG-Cre line was verified using immunofluorescence analysis to show that GFP expression was restricted to the zG. RNA in situ hybridization revealed a 65% downregulation of Klotho messenger RNA expression in the zG of zG-Kl-KO female mice at age 12 weeks compared to control mice. Despite this significant decrease, zG-Kl-KO mice exhibited no difference in plasma aldosterone levels. However, adrenal CYP11B2 expression and the CYP11B2 promotor regulatory transcription factors, NGFIB and Nurr1, were enhanced. Together with in vitro experiments, these results suggest that zG-derived Klotho modulates Cyp11b2 but does not evoke a systemic phenotype in young adult mice on a normal diet. Further studies are required to investigate the role of adrenal Klotho on aldosterone synthesis in aged animals.

PLK1 inhibitors as a new targeted treatment for adrenocortical carcinoma.

Adrenocortical carcinoma (ACC) is an aggressive malignancy with limited treatment options. Polo-like kinase 1 (PLK1) is a promising drug target; PLK1 inhibitors (PLK1i) have been investigated in solid cancers and are more effective in TP53-mutated cases. We evaluated PLK1 expression in ACC samples and the efficacy of two PLK1i in ACC cell lines with different genetic backgrounds. PLK1 protein expression was investigated by immunohistochemistry in tissue samples and correlated with clinical data. The efficacy of rigosertib (RGS), targeting RAS/PI3K, CDKs and PLKs, and poloxin (Pol), specifically targeting the PLK1 polo-box domain, was tested in TP53-mutated NCI-H295R, MUC-1, and CU-ACC2 cells and in TP53 wild-type CU-ACC1. Effects on proliferation, apoptosis, and viability were determined. PLK1 immunostaining was stronger in TP53-mutated ACC samples vs wild-type (P = 0.0017). High PLK1 expression together with TP53 mutations correlated with shorter progression-free survival (P= 0.041). NCI-H295R showed a time- and dose-dependent reduction in proliferation with both PLK1i (P< 0.05at 100 nM RGS and 30 µM Pol). In MUC-1, a less pronounced decrease was observed (P< 0.05at 1000 nM RGS and 100 µM Pol). 100 nM RGS increased apoptosis in NCI-H295R (P< 0.001), with no effect on MUC-1. CU-ACC2 apoptosis was induced only at high concentrations (P < 0.05 at 3000 nM RGS and 100 µM Pol), while proliferation decreased at 1000 nM RGS and 30 µM Pol. CU-ACC1 proliferation reduced, and apoptosis increased, only at 100 µM Pol. TP53-mutated ACC cell lines demonstrated better response to PLK1i than wild-type CU-ACC1. These data suggest PLK1i may be a promising targeted treatment of a subset of ACC patients, pre-selected according to tumour genetic signature.

A Database Tool Integrating Genomic and Pharmacologic Data from Adrenocortical Carcinoma (ACC) Cell Lines, PDX, and Patient Samples.

Adrenocortical carcinoma (ACC) is a rare and highly heterogeneous disease with a notably poor prognosis due to significant challenges in diagnosis and treatment. Emphasising on the importance of precision medicine, there is an increasing need for comprehensive genomic resources alongside well-developed experimental models to devise personalized therapeutic strategies. We present ACC_CellMinerCDB, a substantive genomic and drug sensitivity database (available at https://discover.nci.nih.gov/acc_cellminercdb) comprising ACC cell lines, patient-derived xenografts, surgical samples, combined with responses to over 2,400 drugs examined by NCI and NCATS. This database exposes shared genomic pathways among ACC cell lines and surgical samples, thus authenticating the cell lines as research models. It also allows exploration of pertinent treatment markers such as MDR-1, SOAT1, MGMT, MMR and SLFN11, and introduces the potential to repurpose agents like temozolomide for ACC therapy. ACC_CellMinerCDB provides the foundation for exploring larger preclinical ACC models.

Opposing effects of cannabidiol in patient-derived neuroendocrine tumor, pheochromocytoma/paraganglioma primary cultures.

CONTEXT: Treatment options for advanced neuroendocrine tumors (NETs), pheochromocytomas and paragangliomas (together PPGLs) are still limited. In recent years, anti-tumor effects of cannabinoids have been reported; however, there are only very limited data available in NETs or PPGLs. OBJECTIVE: Investigation of the effects of cannabidiol (CBD) on patient-derived human NET/PPGL primary cultures and on NET/PPGL cell lines. METHODS: We established primary cultures derived from 46 different patients with PPGLs (n = 35) or NETs (n = 11) who underwent tumor resection at two centers. Treatment of patient primary cultures with clinically relevant doses (5 µM) and slightly higher doses (10 µM) of CBD was performed. RESULTS: We found opposing effects of 5 µM CBD: significant anti-tumor effects in 5/35 (14%) and significant tumor-promoting effects in 6/35 (17%) of PPGL primary cultures. In terms of anti-tumor effects, cluster 2-related PPGLs showed significantly stronger responsivity to CBD compared to cluster 1-related PPGLs (p = 0.042). Of the cluster 2-related tumors, NF1 PPGLs showed strongest responsivity (4/5 PPGL primary cultures with a significant decrease in cell viability were NF1-mutated). We also found opposing effects of 10 µM CBD in PPGLs and NETs: significant anti-tumor effects in 9/33 of PPGL (27%) and 3/11 of NET (27%) primary cultures, significant tumor-promoting effects in 6/33 of PPGL (18%) and 2/11 of NET (18%) primary cultures. CONCLUSIONS: We suggest a potential novel treatment option for some NETs/PPGLs, but also provide evidence for caution when applying cannabinoids as supportive therapy for pain or appetite management to cancer patients, and possibly as health supplements.