Recent research has shown that mtDNA-deficient cancer cells (ρ0 cells) acquire mitochondria from tumor stromal cells to restore respiration, facilitating tumor formation. We investigated the role of Miro1, an adaptor protein involved in movement of mitochondria along microtubules, in this phenomenon. Inducible Miro1 knockout (Miro1KO) mice markedly delayed tumor formation after grafting ρ0 cancer cells. Miro1KO mice with fluorescently labeled mitochondria revealed that this delay was due to hindered mitochondrial transfer from the tumor stromal cells to grafted B16 ρ0 cells, which impeded recovery of mitochondrial respiration and tumor growth. Miro1KO led to the perinuclear accumulation of mitochondria and impaired mobility of the mitochondrial network. In vitro experiments revealed decreased association of mitochondria with microtubules, compromising mitochondrial transfer via tunneling nanotubes (TNTs) in mesenchymal stromal cells. Here we show the role of Miro1 in horizontal mitochondrial transfer in mouse melanoma models in vivo and its involvement with TNTs.

• Klíčová slova
• CP: Cancer, CP: Cell biology, Miro1, RHOT1, cancer, horizontal transfer of mitochondria, melanoma, mitochondria, tunneling nanotubes,
• MeSH
• lidé MeSH
• melanom experimentální * patologie   metabolismus   genetika   MeSH
• mezenchymální kmenové buňky metabolismus   MeSH
• mikrotubuly metabolismus   MeSH
• mitochondriální proteiny metabolismus   genetika   MeSH
• mitochondrie * metabolismus   MeSH
• modely nemocí na zvířatech MeSH
• myši inbrední C57BL MeSH
• myši knockoutované * MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• rho proteiny vázající GTP metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• Miro-1 protein, mouse MeSH Prohlížeč
• mitochondriální proteiny MeSH
• rho proteiny vázající GTP MeSH

• MeSH
• imunoterapie * MeSH
• lidé MeSH
• nádory ledvin * farmakoterapie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• dopisy MeSH
• práce podpořená grantem MeSH

Colorectal cancer (CRC) is a disease with constantly increasing incidence and high mortality. The treatment efficacy could be curtailed by drug resistance resulting from poor drug penetration into tumor tissue and the tumor-specific microenvironment, such as hypoxia and acidosis. Furthermore, CRC tumors can be exposed to different pH depending on the position in the intestinal tract. CRC tumors often share upregulation of the Akt signaling pathway. In this study, we investigated the role of external pH in control of cytotoxicity of perifosine, the Akt signaling pathway inhibitor, to CRC cells using 2D and 3D tumor models. In 3D settings, we employed an innovative strategy for simultaneous detection of spatial drug distribution and biological markers of proliferation/apoptosis using a combination of mass spectrometry imaging and immunohistochemistry. In 3D conditions, low and heterogeneous penetration of perifosine into the inner parts of the spheroids was observed. The depth of penetration depended on the treatment duration but not on the external pH. However, pH alteration in the tumor microenvironment affected the distribution of proliferation- and apoptosis-specific markers in the perifosine-treated spheroid. Accurate co-registration of perifosine distribution and biological response in the same spheroid section revealed dynamic changes in apoptotic and proliferative markers occurring not only in the perifosine-exposed cells, but also in the perifosine-free regions. Cytotoxicity of perifosine to both 2D and 3D cultures decreased in an acidic environment below pH 6.7. External pH affects cytotoxicity of the other Akt inhibitor, MK-2206, in a similar way. Our innovative approach for accurate determination of drug efficiency in 3D tumor tissue revealed that cytotoxicity of Akt inhibitors to CRC cells is strongly dependent on pH of the tumor microenvironment. Therefore, the effect of pH should be considered during the design and pre-clinical/clinical testing of the Akt-targeted cancer therapy.

• Klíčová slova
• Akt kinase, alkalization, colorectal cancer, lactic acidosis, mass spectrometry imaging, perifosine, signal co-registration, tumor environment,
• Publikační typ
• časopisecké články MeSH