bioRxiv Science⌕ Search

Biology subjects

Chio, I. I. C.

Publications and source records attributed to Chio, I. I. C..

3 recordsLinked to original sources

Netrin-1 promotes pancreatic tumorigenesis and innervation through NEO1.

Nerves have been shown to regulate cancer progression. However, a clear demonstration of a role for axon guidance molecules in pancreatic tumorigenesis, innervation, and metastasis has been lacking. Using murine KrasG12D-mutant pancreatic organoids, we screened axon guidance molecules by qRT-PCR, identified Ntn1 upregulation, and then verified its in vivo upregulation during pancreatic tumorigenesis in humans and mice. NTN1 and its receptor NEO1 were upregulated in epithelial cells by the Kras mutation and {beta}-adrenergic signaling, in part, through the MAPK pathway. Ex-vivo culture of celiac ganglia showed that NTN1 promoted the axonogenesis of sympathetic neurons through the nerve NEO1 receptor. In the Pdx1-Cre;LSL-KrasG12D/+ model, Ntn1 knockout decreased sympathetic innervation and the development of pancreatic intraepithelial neoplasia. Treatment of pancreatic tumor organoids with recombinant NTN1 enhanced cell growth, epithelial-mesenchymal transition (EMT), and cancer stemness with the upregulation of ZEB1 and SOX9 through NEO1-mediated activation of focal adhesion kinase (FAK). In Pdx1-Cre;LSL-KrasG12D/+;LSL-Trp53R172H/+mice, Ntn1 knockout reduced innervation, FAK phosphorylation, and the features of EMT and stemness to extend mouse survival. In a liver metastasis model of PDAC (pancreatic ductal adenocarcinoma), treatment with a NTN1-neutralizing antibody or tumoral knockdown of Neo1 reduced ZEB1 and SOX9 and decreased tumor progression. In contrast, Ntn1 overexpression promoted innervation and the progression of PDAC liver metastasis. These data suggest that the NTN1/NEO1 axis is a key regulator of PDAC progression, directly influencing cancer cell stemness and EMT, while indirectly promoting tumor growth through nerves. Inhibiting the NTN1/NEO1 axis could represent a potential therapeutic approach for PDAC. Statement of SignificanceNTN1 promotes pancreatic tumorigenesis and metastasis directly and indirectly through nerves, highlighting the importance of tumor cell-nerve crosstalk in cancer. NTN1 blockade could represent a promising strategy for treating PDAC liver metastasis. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=88 SRC="FIGDIR/small/666009v1_ufig1.gif" ALT="Figure 1"> View larger version (19K): org.highwire.dtl.DTLVardef@ca611corg.highwire.dtl.DTLVardef@ad9264org.highwire.dtl.DTLVardef@1661c00org.highwire.dtl.DTLVardef@b86798_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

An Iron-regulated Signalling Pathway Controls Adipose Browning and Cancer Cachexia

The browning and atrophy of white adipose tissue (WAT) are early events in cachexia, a lethal metabolic disorder affecting nearly half of cancer patients, including those with pancreatic ductal adenocarcinoma (PDA). Using patient-derived specimens and PDA mouse models, we identified perturbations in iron metabolism and proteinaceous methionine oxidation as key initiating events of adipose browning. In particular, the iron influxes that accompany WAT browning induce the activity of methionine sulfoxide reductase A (MSRA), an enzyme that reverses the oxidation of proteinaceous methionine residues. Mechanistically, iron coordination by the conserved iron-binding motifs (E203-xx-H206) of two MSRA polypeptides serves to multimerize, stabilize, and enzymatically activate MSRA. This in turns facilitates adipose browning by maintaining the reduced state of two methionines near the ATP-binding site of Protein Kinase A (PKA). Remarkably, in mouse models of PDA, MsrA deletion impairs WAT browning, significantly mitigates cachexia, and improves the overall survival of tumor-bearing animals. By establishing the iron-MSRA-PKA axis as a key nexus of cancer-associated cachexia, our study offers new perspectives for the treatment of this condition.

cancer biology↗

Distinct Nrf2 Signaling Thresholds Mediate Lung Tumor Initiation and Progression

Mutations in the KEAP1-NRF2 pathway occur in up to a third of non-small cell lung cancer (NSCLC) cases and often confer resistance to therapy and poor outcomes. Here, we developed murine alleles of the KEAP1 and NRF2 mutations found in human NSCLC and comprehensively interrogated their impact on tumor initiation and progression. Chronic Nrf2 stabilization by Keap1 or Nrf2 mutation was not sufficient to induce tumorigenesis, even in the absence of tumor suppressors p53 or Lkb1. When combined with KrasG12D/+, constitutive Nrf2 activation promoted lung tumor initiation and early progression of hyperplasia to low-grade tumors but impaired their progression to advanced-grade tumors, which was reversed by Nrf2 deletion. Finally, NRF2 overexpression in KEAP1 mutant NSCLC cell lines was detrimental to cell proliferation, viability, and anchorage-independent colony formation. Collectively, our results establish the context-dependence and activity threshold for NRF2 during the lung tumorigenic process. SignificanceThis study reports murine lung cancer models harboring mutations in the Keap1/Nrf2 pathway and highlights the context-dependent and diverse roles of Nrf2 during lung tumor initiation and progression.

cancer biology↗