Celastrol-induced degradation of FANCD2 sensitizes pediatric high-grade gliomas to the DNA-crosslinking agent carboplatin

Abstract

BackgroundPediatric high-grade gliomas (pHGG) are the leading cause of cancer-related death during childhood. Due to their diffuse growth characteristics, chemoresistance and location behind the blood-brain barrier (BBB), the prognosis of pHGG has barely improved in the past decades. As such, there is a dire need for new therapies that circumvent those difficulties. Since aberrant expression of DNA damage-response associated Fanconi anemia proteins play a central role in the onset and therapy resistance of many cancers, we here investigated if FANCD2 depletion could sensitize pHGG to additional DNA damage.MethodsWe determined the capacity of celastrol, a BBB-penetrable compound that degrades FANCD2, to sensitize glioma cells to the archetypical DNA-crosslinking agent carboplatin in vitro in seven patient-derived pHGG models. In addition, we tested this drug combination in vivo in a patient-derived orthotopic pHGG xenograft model. Underlying mechanisms to drug response were investigated using mRNA expression profiling, western blotting, immunofluorescence, FANCD2 knockdown and DNA fiber assays.FindingsFANCD2 is overexpressed in HGGs and depletion of FANCD2 by celastrol synergises with carboplatin to induce cytotoxicity. Combination therapy prolongs survival of pHGG-bearing mice over monotherapy and control groups in vivo (P<0.05). In addition, our results suggest that celastrol treatment stalls ongoing replication forks, causing sensitivity to DNA-crosslinking in FANCD2-dependent glioma cells.InterpretationOur results show that depletion of FANCD2 acts as a chemo-sensitizing strategy in pHGG. Combination therapy using celastrol and carboplatin might serve as a clinically relevant strategy for the treatment of pHGG.FundingThis study was funded by a grant from the Children Cancer-Free Foundation (KIKA, project 210). The disclosed funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Nanotechnology-Based Celastrol Formulations and Their Therapeutic Applications

“…At these doses, though effective, systemic toxicities including cardiotoxicity (Liu et al, 2019), hepatotoxicity (Jin et al, 2019), and nephrotoxicity (Wu et al, 2018) have been reported, whereas lower doses, though safe, show limited efficacy. To overcome the toxicity issues while achieving the desired therapeutic efficacy, various drug delivery approaches have been investigated that include combination with other chemotherapeutic agents such as afatinib, axitinib, and gefitinib (Zhang et al, 2014;Choi et al, 2016;Gao et al, 2019;Zhao et al, 2019;Dai et al, 2020), combination with traditional Chinese medicines such as betulinic and ellagic acids (An et al, 2015;Duan et al, 2019), overcoming multidrug resistance (Metselaar et al, 2019), nanoparticulate drug delivery systems (Qi et al, 2014;Hakala et al, 2020;, and combination with nucleic acid (Huang et al, 2017). Among these, nanoparticulate drug delivery systems/ nanoformulations of celastrol have been widely reported as a promising strategy to effectively deliver drug at the target site rendering enhanced efficacy and safety.…”

Celastrol: A Review of Useful Strategies Overcoming its Limitation in Anticancer Application

“…The findings not only open new opportunities for the clinical development of SAHA but should also motivate the clinical investigation of celastrol, which has been hampered by its toxicity. On the other hand, celastrol, as a blood-brain barrierpenetrable compound, could degrade FANCD2, to sensitize glioma cells to the archetypical DNA-crosslinking agent carboplatin in vitro in seven patient-derived pediatric highgrade gliomas (pHGG) models (Metselaar et al, 2019). Therefore, combination therapy using celastrol and carboplatin might serve as a clinically relevant strategy for the treatment of pHGG.…”

Revisiting Platinum-Based Anticancer Drugs to Overcome Gliomas

“…Thus, the molecular mechanism of carboplatin resistance occurs through the regulation of Mcl-1 and c-FLIP by the elevation of Nrf2-dependent PSMA5 expression in glioma cells. Recently, there has been a study related to Fanconi anemia group D2 protein (FANCD2) as a modulating factor of carboplatin sensitivity in pediatric high-grade glioma (pHGG) [ 148 ]. pHGG is characterized by epigenetic alterations and defects in DNA damage repair genes and causes the occurrence of malignant brain tumors due to a syndrome called Fanconi anemia, a genetic disorder that results from disruption of the Fanconi DNA repair mechanism [ 149 , 150 ].…”

“…In addition, carboplatin induced sensitivity to FANCD2-dependent DNA crosslinking in glioma cells. Thus, these findings show that FANCD2 regulation acts as a strategy to overcome chemical resistance in pHGG [ 148 , 153 ].…”