Inhibition of IRP2-dependent reprogramming of iron metabolism suppresses tumor growth in colorectal cancer.

BACKGROUND: Dysregulation of iron metabolism is implicated in malignant transformation, cancer progression, and therapeutic resistance. Here, we demonstrate that iron regulatory protein 2 (IRP2) preferentially regulates iron metabolism and promotes tumor growth in colorectal cancer (CRC). METHODS: IRP2 knockdown and knockout cells were generated using RNA interference and clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 methodologies, respectively. Cell viability was evaluated using both CCK-8 assay and cell counting techniques. Furthermore, IRP2 inhibition was determined by surface plasmon resonance (SPR) and RNA immunoprecipitation (IP). The suppressive effects of IRP2 were also corroborated in both organoid and mouse xenograft models, providing a comprehensive validation of IRP2's role. RESULTS: We have elucidated the role of IRP2 as a preferential regulator of iron metabolism, actively promoting tumorigenesis within CRC. Elevated levels of IRP2 expression in patient samples are correlated with diminished overall survival, thereby reinforcing its potential role as a prognostic biomarker. The functional suppression of IRP2 resulted in a pronounced delay in tumor growth. Building on this proof of concept, we have developed IRP2 inhibitors that significantly reduce IRP2 expression and hinder its interaction with iron-responsive elements in key iron-regulating proteins, such as ferritin heavy chain 1 (FTH1) and transferrin receptor (TFRC), culminating in iron depletion and a marked reduction in CRC cell proliferation. Furthermore, these inhibitors are shown to activate the AMPK-ULK1-Beclin1 signaling cascade, leading to cell death in CRC models. CONCLUSIONS: Collectively, these findings highlight the therapeutic potential of targeting IRP2 to exploit the disruption of iron metabolism in CRC, presenting a strategic advancement in addressing a critical area of unmet clinical need.

Suppression of DYRK1A/B Drives Endoplasmic Reticulum Stress-mediated Autophagic Cell Death Through Metabolic Reprogramming in Colorectal Cancer Cells.

BACKGROUND/AIM: We previously identified KS40008 (4-(3-(4-hydroxyphenyl)-1H-pyrazolo[3,4-b]pyridin-5-yl)benzene-1,2-diol), a novel inhibitor of dual-specificity tyrosine phosphorylation-regulated kinase family (DYRK) 1A/B, which exhibited high enzymatic activity and cell proliferation-inhibitory effects in colorectal cancer (CRC) cell lines. In the present study, we aimed to elucidate the antitumor mechanisms of KS40008. MATERIALS AND METHODS: To assess the cytotoxicity of KS40008, we utilized a human cell line and organoid model and performed a CCK-8 assay and real-time cell analysis. Mitochondrial function was determined through mitochondrial staining, mito-stress test, and glycolysis test. In addition, we investigated the mechanisms of cancer cell death induced by KS40008 through immunoblotting, real-time quantitative polymerase chain reaction, reactive oxygen species staining, and immunofluorescence staining. RESULTS: KS40008 exhibited significant cytotoxicity in CRC and non-CRC cell lines, and organoid models compared to 5-fluorouracil, a conventional chemotherapeutic drug. Moreover, KS40008-induced inhibition of DYRK1A/B led to mitochondrial dysfunction and endoplasmic reticulum stress, promoting autophagic cancer cell death. CONCLUSION: KS40008 exerts antitumor activity through the inhibition of DYRK1A/B. Here, we demonstrated a mechanism by which KS40008 affects endoplasmic reticulum stress-mediated autophagy through the induction of mitochondrial stress, leading to cytotoxicity in CRC.