Search bioRxiv⌕ Search

Biology subjects

Mange, A.

Publications and source records attributed to Mange, A..

3 recordsLinked to original sources

Cfap410a and Cby work together with tissue-specific requirements to build Drosophila ciliary transition zones

Cilia and flagella perform essential physiological functions in eukaryotes, and defects in these organelles cause several human diseases, including cancer and ciliopathies. The architecture of cilia is highly organized. The ciliary compartment is separated from the cytoplasm by the transition zone (TZ). The severity of ciliopathies linked to TZ assembly defects highlights the TZ's critical role. Although several core conserved complexes are involved in TZ assembly, variations in TZ composition are associated with structurally and functionally diverse cilia. Here, we identify Cfap410a as a novel component of the ciliary TZ in the two Drosophila ciliated tissues, male germ cells and sensory neurons. Cfap410a is one of the two Drosophila paralogs (Cfap410a and Cfap410b) of human CFAP410, whose mutations are associated with axial spondylo-metaphyseal dysplasia, retinitis pigmentosa and amyotrophic lateral sclerosis. We show here that Cfap410a is a proximity partner of Cby and that they act cooperatively in the hierarchy of the TZ assembly program by bridging the CEP290 and MKS transition zone modules. Simultaneous loss of Cfap410a and Cby halts ciliary growth by disrupting TZ formation in multiple types of Drosophila ciliated cells, each of which exhibiting varying dependence on these two proteins. Interestingly, the function of Cfap410a and Cfap410b are not functionally redundant, indicating that the two proteins have evolved towards specific functions. In summary, our results propose a novel role for CFAP410a at the TZ and provide an explanation for how deregulation of conserved TZ components could lead to tissue-specific ciliopathies.

cell biology↗

Occurrence of Biased mTOR Signaling in Hepatocellular Carcinoma

BackgroundmTOR signaling promotes cell growth and anabolic processes in all eukaryotes. Hyperactivation of mTOR signaling is associated with various cancers along with hepatocellular carcinoma (HCC). HCC is a highly lethal malignancy with multiple aetiologies such as viral infection, alcohol abuse, and metabolic dysfunction. Therapeutic options for HCC remain limited due to an incomplete understanding of oncogenic drivers and poorly characterized mechanisms of disease progression. MethodsVarious regimens of DEN and CCl4 carcinogen dosage were investigated on C57BL/6J mice to induce HCC. The histological analysis for fibrosis and serum markers for liver function were performed. Molecular analyses of oncogenic drivers were performed in the HCC tissues obtained from mice and HCC patients. The impact of inhibition of mTOR signaling was assessed on HCC progression. ResultsWe established a rapid DEN+CCl4 induced (DCI) HCC model in C57BL/6 mice to study disease progression longitudinally. The molecular analysis revealed upregulation of MAPK and downregulation of mTORC1-S6K-S6 signaling in HCC. However, other branches of mTOR such as mTORC1-ULK1, mTORC1-4EBP1, and mTORC2-PKC were upregulated due to the increased expression. Similar observations were found in tissues derived from HCC patients. Furthermore, inhibition of mTORC1 alone by Rapamycin did not reduce HCC progression but Torin 1 mediated inhibition of both mTORC1 and mTORC2 significantly reduced HCC progression. ConclusionsWe propose this biased mTOR signaling modulates mTOR activity towards specific downstream processes that are crucial for cancer cell growth and targeting both the mTOR complexes has better therapeutic potential in HCC. Impact and ImplicationsThis study provides a rapid pre-clinical model for understanding HCC progression and to explore various intervention strategies. The study reports a novel phenomenon of biased mTOR signaling where deregulation of downstream substrate levels modulates the mTOR activity towards the specific branches, the master regulator of cell growth and metabolism. Furthermore, the study suggests that the clinical investigations exploring the rapalogs against HCC should be cautiously considered depending on the aetiology and signaling status of HCC. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=125 SRC="FIGDIR/small/727188v2_ufig1.gif" ALT="Figure 1"> View larger version (20K): org.highwire.dtl.DTLVardef@ef3714org.highwire.dtl.DTLVardef@1091b25org.highwire.dtl.DTLVardef@d52f2forg.highwire.dtl.DTLVardef@cc158_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIDEN and CCl4 treatment generated a well-established HCC within 4 months. C_LIO_LILiver fibrosis and serum markers correlated with HCC progression. C_LIO_LIUpregulation of mTOR pathway substrates create biased mTOR signaling. C_LIO_LIDual inhibition of mTORC1 and mTORC2 reduced HCC progression significantly. C_LI

cancer biology↗

FMO4 drives lung adenocarcinoma by stabilizing the MAT2A/MAT2B complex and hindering ferroptosis

Lung cancer is the leading cause of death by cancer in the world and finding new targets is a major medical need to tackle this disease. Here, upon proteomic analysis to identify common players in oncogenic EGFR- and KRAS-driven lung adenocarcinoma mouse models, we uncovered a largely unknown protein in cancer, flavin-containing monooxygenase 4 (FMO4), whose expression was increased in lung tumors compared with adjacent lung tissue. FMO4 expression was strongly increased also in lung cancer samples from patients compared with healthy lung, and its expression level was inversely correlated with overall survival. Remarkably, in vivo deletion of FMO4 greatly decreased tumor burden and increased survival in oncogenic KRAS-driven lung adenocarcinoma mice unveiling its crucial role in tumor biology. Mechanistically, we found that FMO4 loss of function promotes ferroptosis and cooperates with ferroptosis inducers in vitro and in vivo. Moreover, FMO4 facilitates the interaction between MAT2A and MAT2B, promoting the generation of cysteine from methionine, which in turn boosts the generation of glutathione, thus protecting lung adenocarcinoma against ferroptosis. In summary we identified a new target in lung adenocarcinoma with important implications in cancer biology.

cancer biology↗