Related Experiment Video
Updated: Aug 1, 2025
Author Spotlight: Finding New Therapeutic Targets for Malignant Peripheral Nerve Sheath Tumor Through Genome-Scale shRNA Screens
Published on: August 25, 2023
High-throughput and targeted drug screens identify pharmacological candidates against MiT-translocation renal cell
Martin Lang1,2, Laura S Schmidt1,3, Kelli M Wilson4
1Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
Background:
MiT-Renal Cell Carcinoma (RCC) is characterized by genomic translocations involving microphthalmia-associated transcription factor (MiT) family members TFE3, TFEB, or MITF. MiT-RCC represents a specific subtype of sporadic RCC that is predominantly seen in young patients and can present with heterogeneous histological features making diagnosis challenging. Moreover, the disease biology of this aggressive cancer is poorly understood and there is no accepted standard of care therapy for patients with advanced disease. Tumor-derived cell lines have been established from human TFE3-RCC providing useful models for preclinical studies.
Methods:
TFE3-RCC tumor derived cell lines and their tissues of origin were characterized by IHC and gene expression analyses. An unbiased high-throughput drug screen was performed to identify novel therapeutic agents for treatment of MiT-RCC. Potential therapeutic candidates were validated in in vitro and in vivo preclinical studies. Mechanistic assays were conducted to confirm the on-target effects of drugs.
Results:
The results of a high-throughput small molecule drug screen utilizing three TFE3-RCC tumor-derived cell lines identified five classes of agents with potential pharmacological efficacy, including inhibitors of phosphoinositide-3-kinase (PI3K) and mechanistic target of rapamycin (mTOR), and several additional agents, including the transcription inhibitor Mithramycin A. Upregulation of the cell surface marker GPNMB, a specific MiT transcriptional target, was confirmed in TFE3-RCC and evaluated as a therapeutic target using the GPNMB-targeted antibody-drug conjugate CDX-011. In vitro and in vivo preclinical studies demonstrated efficacy of the PI3K/mTOR inhibitor NVP-BGT226, Mithramycin A, and CDX-011 as potential therapeutic options for treating advanced MiT-RCC as single agents or in combination.
Conclusions:
The results of the high-throughput drug screen and validation studies in TFE3-RCC tumor-derived cell lines have provided in vitro and in vivo preclinical data supporting the efficacy of the PI3K/mTOR inhibitor NVP-BGT226, the transcription inhibitor Mithramycin A, and GPNMB-targeted antibody-drug conjugate CDX-011 as potential therapeutic options for treating advanced MiT-RCC. The findings presented here should provide the basis for designing future clinical trials for patients with MiT-driven RCC.
Insights
This study identified novel therapeutic agents for MiT-Renal Cell Carcinoma (RCC), including PI3K/mTOR inhibitors, Mithramycin A, and a GPNMB-targeted antibody-drug conjugate. These agents show promise for treating advanced MiT-RCC in preclinical models.
Area of Science:
- Oncology
- Genetics
- Pharmacology
Background:
- MiT-Renal Cell Carcinoma (RCC) is a rare subtype characterized by genomic translocations involving MiT family members.
- This aggressive cancer predominantly affects young patients and presents diagnostic challenges due to heterogeneous histology.
- The disease biology of MiT-RCC is poorly understood, with no established standard of care for advanced stages.
Purpose of the Study:
- To identify novel therapeutic agents for MiT-RCC through high-throughput drug screening.
- To validate potential therapeutic candidates in preclinical in vitro and in vivo models.
- To investigate the efficacy of targeted therapies for advanced MiT-RCC.
Main Methods:
- Characterization of TFE3-RCC tumor-derived cell lines and patient tissues using IHC and gene expression analysis.
- Unbiased high-throughput screening of small molecules to identify potential therapeutic agents.
- Preclinical validation of drug candidates through in vitro and in vivo studies, including mechanistic assays.
Main Results:
- A drug screen identified five classes of agents with potential efficacy, including PI3K/mTOR inhibitors and Mithramycin A.
- Upregulation of GPNMB, a MiT transcriptional target, was confirmed in TFE3-RCC, and its targeted conjugate CDX-011 was evaluated.
- NVP-BGT226 (PI3K/mTOR inhibitor), Mithramycin A, and CDX-011 demonstrated efficacy as single agents or in combination in preclinical studies.
Conclusions:
- Preclinical data support the efficacy of NVP-BGT226, Mithramycin A, and CDX-011 for treating advanced MiT-RCC.
- These findings provide a basis for future clinical trials in patients with MiT-driven RCC.
- Targeted therapies targeting PI3K/mTOR, transcription, and GPNMB show therapeutic potential for MiT-RCC.
