Zinc Inhibits Hedgehog Autoprocessing

Xie, Jierui; Owen, Timothy S.; Xia, Ke; Singh, Ajay Vikram; Tou, Emiley; Li, Lingyun; Arduini, Brigitte L.; Li, Hongmin; Wan, Leo Q.; Callahan, Brian P.; Wang, Chunyu

doi:10.1074/jbc.m114.623264

Cited by 16 publications

(23 citation statements)

References 61 publications

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“…[3b] Activity of SHhN–DHhC toward cholesterol has been established by SDS-PAGE analysis and mass spectrometry. [3b,14] Reactions of SHhN–DHhC in solutions containing A , G , or cholesterol monitored by SDS-PAGE are shown in Figure 2D. Consistent with the kinetic studies above, results indicate that both synthetic sterols stimulate processing of the precursor into SHhN–sterol and DHhC.…”

supporting

confidence: 81%

Hedgehog Proteins Consume Steroidal CYP17A1 Antagonists: Potential Therapeutic Significance in Advanced Prostate Cancer

2016

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Abiraterone, a potent inhibitor of the human enzyme CYP17A1 (cytochrome P450c17), provides a last line of defense against ectopic androgenesis in advanced prostate cancer. Herein we report an unprecedented off-target interaction between abiraterone and oncogenic hedgehog proteins. Our experiments indicate that abiraterone and its structural congener, galeterone, can replace cholesterol as a substrate in a specialized biosynthetic event of hedgehog proteins, known as cholesterolysis. The off-target reaction generates covalent hedgehog–drug conjugates. Cell-based reporter assays indicate that these conjugates activate hedgehog signaling when present in the low nanomolar range. Because hedgehog signaling is implicated in prostate cancer progression, and abiraterone is administered to treat advanced stages of the disease, this off-target interaction may have therapeutic significance.

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supporting

confidence: 81%

Hedgehog Proteins Consume Steroidal CYP17A1 Antagonists: Potential Therapeutic Significance in Advanced Prostate Cancer

2016

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“…Abnormal Hh autoprocessing in development leads to congenital diseases. Recently, we provided evidence that abnormal Hh autoprocessing may be linked to zinc deficiency 22 and metabolism of antiprostate cancer drugs. 23 Our results in this paper improve our understanding of Hh’s unique autoprocessing mechanism while providing a foothold 18 to correct aberrant Hh levels in developmental disorders and cancer.…”

Section: D46 Coordinates the Two Steps Through Side-chain Proton Shutmentioning

confidence: 99%

“…2,3 Cholesteroylation of Hh slows the rate of extracellular diffusion, giving rise to finely regulated signaling gradients during embryogenesis. 4 Mutagenesis studies show that abolishing cholesteroylation prevents Hh ligand secretion, resulting in the degradation of premature Hh ligand, and blockade of downstream signaling events.…”

mentioning

confidence: 99%

A Single Aspartate Coordinates Two Catalytic Steps in Hedgehog Autoprocessing

Xie¹,

Owen

Xia³

et al. 2016

J. Am. Chem. Soc.

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Hedgehog (Hh) signaling is driven by the cholesterol-modified Hh ligand, generated by autoprocessing of Hh precursor protein. Two steps in Hh autoprocessing, N–S acyl shift and transesterification, must be coupled for efficient Hh cholesteroylation and downstream signal transduction. In the present study, we show that a conserved aspartate residue, D46 of the Hh autoprocessing domain, coordinates these two catalytic steps. Mutagenesis demonstrated that D46 suppresses non-native Hh precursor autoprocessing and is indispensable for transesterification with cholesterol. NMR measurements indicated that D46 has a pKa of 5.6, ~2 units above the expected pKa of aspartate, due to a hydrogen-bond between protonated D46 and a catalytic cysteine residue. However, the deprotonated form of D46 side chain is also essential, because a D46N mutation cannot mediate cholesteroylation. On the basis of these data, we propose that the proton shuttling of D46 side chain mechanistically couples the two steps of Hh cholesteroylation.

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“…Conversely, ZNT transporters decrease cytosolic zinc. Altered zinc homeostasis may be permissive for PCa development, as zinc regulates crucial pathways involved in carcinogenesis including proliferation, apoptosis, and cellular metabolism 3 , 10 , 11 . In PCa cells, zinc inhibits proliferation by blocking the G2/M cell cycle check point 12 , and is pro-apoptotic by several mechanisms including increased Bax/BCL-2 ratio 13 and decreased NF-κB leading to caspase 3/7 activation 14 .…”

Section: Introductionmentioning

confidence: 99%

The miR-183 family cluster alters zinc homeostasis in benign prostate cells, organoids and prostate cancer xenografts

Dambal

Baumann

McCray

et al. 2017

Sci Rep

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The miR-183 cluster, which is comprised of paralogous miRs-183, -96 and -182, is overexpressed in many cancers, including prostate adenocarcinoma (PCa). Prior studies showed that overexpression of individual pre-miRs-182, -96 and -183 in prostate cells decreased zinc import, which is a characteristic feature of PCa tumours. Zinc is concentrated in healthy prostate 10-fold higher than any other tissue, and an >80% decrease in zinc is observed in PCa specimens. Here, we studied the effect of overexpression of the entire 4.8 kb miR-183 family cluster, including the intergenic region which contains highly conserved genomic regions, in prostate cells. This resulted in overexpression of mature miR-183 family miRs at levels that mimic cancer-related changes. Overexpression of the miR-183 cluster reduced zinc transporter and intracellular zinc levels in benign prostate cells, PCa xenografts and fresh prostate epithelial organoids. Microarray analysis of miR-183 family cluster overexpression in prostate cells showed an enrichment for cancer-related pathways including adhesion, migration and wound healing. An active secondary transcription start site was identified within the intergenic region of the miR-183 cluster, which may regulate expression of miR-182. Taken together, this study shows that physiologically relevant expression of the miR-183 family regulates zinc levels and carcinogenic pathways in prostate cells.

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Zinc Inhibits Hedgehog Autoprocessing

Cited by 16 publications

References 61 publications

Hedgehog Proteins Consume Steroidal CYP17A1 Antagonists: Potential Therapeutic Significance in Advanced Prostate Cancer

Hedgehog Proteins Consume Steroidal CYP17A1 Antagonists: Potential Therapeutic Significance in Advanced Prostate Cancer

A Single Aspartate Coordinates Two Catalytic Steps in Hedgehog Autoprocessing

The miR-183 family cluster alters zinc homeostasis in benign prostate cells, organoids and prostate cancer xenografts

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