Petasin potently inhibits mitochondrial complex I–based metabolism that supports tumor growth and metastasis
Kazuki Heishima, … , Hiroshi Ueda, Yukihiro Akao
Kazuki Heishima, … , Hiroshi Ueda, Yukihiro Akao
Published September 1, 2021
Citation Information: J Clin Invest. 2021;131(17):e139933. https://doi.org/10.1172/JCI139933.
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Research Article Metabolism Oncology

Petasin potently inhibits mitochondrial complex I–based metabolism that supports tumor growth and metastasis

Abstract

Mitochondrial electron transport chain complex I (ETCC1) is the essential core of cancer metabolism, yet potent ETCC1 inhibitors capable of safely suppressing tumor growth and metastasis in vivo are limited. From a plant extract screening, we identified petasin (PT) as a highly potent ETCC1 inhibitor with a chemical structure distinct from conventional inhibitors. PT had at least 1700 times higher activity than that of metformin or phenformin and induced cytotoxicity against a broad spectrum of tumor types. PT administration also induced prominent growth inhibition in multiple syngeneic and xenograft mouse models in vivo. Despite its higher potency, it showed no apparent toxicity toward nontumor cells and normal organs. Also, treatment with PT attenuated cellular motility and focal adhesion in vitro as well as lung metastasis in vivo. Metabolome and proteome analyses revealed that PT severely depleted the level of aspartate, disrupted tumor-associated metabolism of nucleotide synthesis and glycosylation, and downregulated major oncoproteins associated with proliferation and metastasis. These findings indicate the promising potential of PT as a potent ETCC1 inhibitor to target the metabolic vulnerability of tumor cells.

Authors

Kazuki Heishima, Nobuhiko Sugito, Tomoyoshi Soga, Masashi Nishikawa, Yuko Ito, Ryo Honda, Yuki Kuranaga, Hiroki Sakai, Ryo Ito, Takayuki Nakagawa, Hiroshi Ueda, Yukihiro Akao

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Figure 7

Petasin treatment downregulates oncoproteins and upregulates protein-degradative pathways.

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Petasin treatment downregulates oncoproteins and upregulates protein-deg...
(A) Proteome analysis results showing significantly altered proteins (absolute log2 fold change ≥ 1, P ≤ 0.05; 2-tailed, unpaired Student’s t test, n = 2) and pathways (top 7 pathways with P ≤ 0.001, Metascape enrichment analysis using KEGG or Reactome pathways) in B16F10 cells treated for 72 hours with PT (3 μM). Genes and pathways are marked in color depending on their properties (red, tumor associated; blue, mitochondria associated; green, protein degradation associated). The downregulated proteins or pathways were mainly associated with proliferation or metastasis, whereas upregulated ones were associated with protein degradation. (B) Frequently listed genes in the altered pathways. The font size indicates the frequency that each gene appeared in the pathways, with larger size indicating greater frequency. Genes are marked with color depending on their properties (red, tumor associated; green, protein degradation associated). (C) Percentage of glycoprotein-encoding genes among the downregulated genes. Tumor-associated genes are marked in red. (D) Immunoblots for oncoproteins and metabolism-related proteins in melanoma (B16F10, A2058), pancreatic cancer (MiaPaCa2), chronic myeloid leukemia (K562), and nontumor (ASF 4-1 and HMEC) cell lines (loading control: β-actin). Glycosylation levels of glycoproteins were significantly reduced in tumor cell lines but not in nontumor cell lines. (E) Time-course changes in oncoproteins, ATP/ADP ratio, and medium glucose concentration in B16F10 cells treated with PT (3 μM) or DMSO. The downregulation of oncoproteins started before the drops in the ATP/ADP ratio and medium glucose concentration. The data were obtained from the same membrane for each target for comparison between different durations of treatment (intact images, Supplemental Figure 6C). High-glucose DMEM supplemented with 10% FBS was used for the assays. Data are presented as the mean ± SD (n = 3) unless otherwise indicated.