AUY922 induces retinal toxicity through attenuating TRPM1

Abstract

Background Ocular adverse events are common dose-limiting toxicities in cancer patients treated with HSP90 inhibitors, such as AUY922; however, the pathology and molecular mechanisms that mediate AUY922-induced retinal toxicity remain undescribed. Methods The impact of AUY922 on mouse retinas and cell lines was comprehensively investigated using isobaric tags for relative and absolute quantitation (iTRAQ)‑based proteomic profiling and pathway enrichment analysis, immunohistochemistry and immunofluorescence staining, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, MTT assay, colony formation assay, and western blot analysis. The effect of AUY922 on the Transient Receptor Potential cation channel subfamily M member 1 (TRPM1)-HSP90 chaperone complex was characterized by coimmunoprecipitation. TRPM1-regulated gene expression was analyzed by RNAseq analysis and gene set enrichment analysis (GSEA). The role of TRPM1 was assessed using both loss-of-function and gain-of-function approaches. Results Here, we show that the treatment with AUY922 induced retinal damage and cell apoptosis, dysregulated the photoreceptor and retinal pigment epithelium (RPE) layers, and reduced TRPM1 expression. Proteomic profiling and functional annotation of differentially expressed proteins reveals that those related to stress responses, protein folding processes, regulation of apoptosis, cell cycle and growth, reactive oxygen species (ROS) response, cell junction assembly and adhesion regulation, and proton transmembrane transport were significantly enriched in AUY922-treated cells. We found that AUY922 triggered caspase-3-dependent cell apoptosis, increased ROS production and inhibited cell growth. We determined that TRPM1 is a bona fide HSP90 client and characterized that AUY922 may reduce TRPM1 expression by disrupting the CDC37-HSP90 chaperone complex. Additionally, GSEA revealed that TRPM1-regulated genes were associated with retinal morphogenesis in camera-type eyes and the JAK-STAT cascade. Finally, gain-of-function and loss-of-function analyses validated the finding that TRPM1 mediated the cell apoptosis, ROS production and growth inhibition induced by AUY922. Conclusions Our study demonstrates the pathology of AUY922-induced retinal toxicity in vivo. TRPM1 is an HSP90 client, regulates photoreceptor morphology and function, and mediates AUY922-induced cytotoxicity.

CHK2 activation contributes to the development of oxaliplatin resistance in colorectal cancer

“…The stained tissues were photographed using a light microscope (the gain was set to 1.0x, saturation to 1.00, and gamma to 1.01, Leica DM2000), and their histopathological characteristics were interpreted by two independent investigators. The expression of pCHK2T68 was semiquantitatively evaluated using the H-score [ 24 ] by two independent investigators. The staining intensity was classified into no staining (0), weakly positive [ 1 ], moderately positive [ 2 ] and strongly positive [ 3 ].…”

The Role of Hsp90 in Retinal Proteostasis and Disease

“…Despite the plethora of evidence that Hsp90 inhibition can provide protection in the diseased retina as described above, reports from clinical trials in oncology highlight ocular toxicities that have emerged as an important clinical concern ( Table 2 ). Hsp90 N-terminal inhibitors, including ansamycin derivatives (17-dimethylaminoethylamino-17-demethoxygeldanamycin (17-DMAG)), resorcinol derivatives (AT13387, AUY922), and benzamide derivatives (SNX-5422 (PF-04929113)), have been associated with visual disturbances, such as blurred vision, photopsia, night blindness, photophobia, and retinopathy [ 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 ]. In addition, some preclinical studies have reported that severe retinal degeneration occurred in rats and beagle dogs after treatment with Hsp90 inhibitors [ 46 , 58 , 59 ].The oral administration of the Hsp90 scaffold N-terminal inhibitor CH5164840 led to a loss of pupillary light reflex, abnormal electroretinographic (ERG) responses, and histological changes in the photoreceptor outer nuclear layer, including photoreceptor degeneration, in beagle dogs [ 58 ].…”

“…As described previously, GRK1 biosynthesis requires Hsp90, and prolonged Hsp90 inhibition via systemic administration of HSP990 reduced GRK1 and PDE6 levels post-translationally, suggesting that the Hsp90 client list includes important components of the phototransduction cascade. More recently, Transient Receptor Potential cation channel subfamily M member 1 (TRPM1) has been identified as another potential Hsp90 client protein in the retina [ 57 ]. TRPM1 is a constitutively open calcium entry channel primarily expressed in skin melanocytes and retinal ON-bipolar cells in the inner nuclear layer.…”

“…TRPM1 is a constitutively open calcium entry channel primarily expressed in skin melanocytes and retinal ON-bipolar cells in the inner nuclear layer. The treatment of mice with AUY922 resulted in increased apoptosis in the photoreceptor outer nuclear layer, disorganization of the photoreceptor outer segments, disruption of RPE cells, and a dose-dependent decrease in TRPM1 via disruption of the interaction with Hsp90 [ 57 ].…”

Genipin protects against mitochondrial damage of the retinal pigment epithelium under hyperglycemia through the AKT pathway mediated by the miR-4429/JAK2 signaling axis

“…2 (IL-2) can regulate the expression of inflammatory cytokines in RPE cells through JAK2 and reduce the activity of RPE cells(27). Glycosylated serum protein can promote the secretion of inflammatory cytokines (IL-8) and the expression of MCP-1 by RPE cells through JAK2, thus affecting the function and activity of RPE cells(28). At the same time, a study has shown that the expression level of JAK2 is closely related to mitochondrial function, and extracellular IL-6 can affect the physiological function of intracellular mitochondria by regulating the expression of JAK2(29).…”