Biology subjects

Henchy, C.

Publications and source records attributed to Henchy, C..

4 recordsLinked to original sources

bioRxiv2025

Reversible Dissociation of Mitochondrial Complex V Balances Anabolic and Energy-Generating Needs in Cancer

Cancer cell metabolic re-programming provides the excess energy and anabolic precursors necessary to sustain uncontrolled growth. This is partly mediated by the Warburg effect, whereby glucose is converted into ATP and a subset of these anabolic substrates. Concurrently, mitochondrial mass and ATP production decline in most tumors. This raises the question of how increased supplies of glycolysis-derived anabolic substrates can be balanced with those generated by the TCA cycle. Using primary murine liver cancers and cell lines, we show that this can be explained by the dissociation of mitochondrial Complex V (CV or ATP synthase) into its component and functionally-independent Fo and F1 domains. This occurs as a result of marked reductions in MT-ATP6, a CV subunit that stabilizes the Fo-F1 association. Serving as a proton pore, Fo maintains a normal mitochondrial membrane potential without generating ATP, thus allowing the TCA cycle, electron transport chain and anaplerotic reactions to function at high levels. Concurrently, free F1 functions as an ATPase to prevent excessive ATP accumulation. The uncoupling of TCA cycle-derived anabolic substrate production from membrane hyperpolarization and ATP synthesis by a smaller population of more efficient mitochondria allows TCA cycle-generated anabolic precursors to match those generated via glycolysis.

cancer biology↗

bioRxiv2025

Derivation of Genetically-Defined Murine Hepatoblastoma Cell Lines with Angiogenic Potential

Background/ObjectivesHepatoblastoma (HB) is the most common form of pediatric liver cancer, with the vast majority of these tumors evidence of mutation and/or deregulation of the oncogenic transcription factors {beta}-catenin (B), YAP (Y) and NRF2 (N). HB research has been hampered by a paucity of established cell lines, particularly those bearing these molecular drivers. All combinations of B, Y and N (i.e. BY, BN, YN and BYN) are tumorigenic when over-expressed in murine livers but it has not been possible to establish cell lines from primary tumors. Recently, we found that concurrent Crispr-mediate targeting of the Cdkn2a tumor suppressor locus allows for such immor-talized cell lines to be generated with high fidelity. MethodsWe generated 5 immortalized cell lines from primary Cdkn2a-targeted BN and YN HBs and characterized their properties. Notably, 4 of the 5 retain their ability to grow as subcutaneous or pulmonary tumors in the immune-competent mice from which they originated. Most notably, when maintained under hypoxia conditions for as little as 2 days, BN cells reversibly up-regulated the expression of numerous endothelial cell (EC)-specific genes and ac-quired EC-like properties that benefited tumor growth. ConclusionsThe above approach is currently the only means by which HB cell lines with pre-selected, clinically relevant oncogenic drivers can be generated and the only ones that can be studied in immune-competent mice. Its generic nature should allow HB cell lines with other oncogenic drivers to be derived. A collection of such cell lines will be useful for studying tumor cell-EC trans-differentiation, interactions with the immune environment and drug sensitivities. Simple SummaryMost hepatoblastomas (HB) are associated with aberrant expression of {beta}-catenin (B), YAP (Y) and/or NRF2 (N) transcription factors and can be modeled in mice by over-expressing pairwise of triple combination of these. Virtually no human or murine HB cell lines exist that bear these mutations. We describe here an efficient way to generate cell lines from primary BN and YN tumors. Moreover, one of the BN lines shows a remarkable ability to trans-differentiate into endothelial cells under hypoxic conditions that may facilitate angiogenesis. These cell lines along with previousl-derived BN and BYN lines showed similar sensitivities to drugs commonly used to treat HB. Because the approach for cell line derivation we describe is quite general, it should allow for the generation of additional lines driven by less common factors. A collection of such permanent and well-characterized cell lines will facilitate studies that are difficult or impractical to perform in vivo.

cancer biology↗

bioRxiv2024

Gas1-Mediated Suppression of Hepatoblastoma Tumorigenesis

Background and AimsHepatoblastoma (HB), the most common pediatric liver cancer, often dysregulates the Wnt/{beta}-catenin, Hippo and NFE2L2/NRF2 pathways. Pairwise combinations of oncogenically active forms of the terminal transcription factor effectors of these pathways, namely {beta}-catenin (B), YAP (Y) and NRF2 (N) generate HBs in mice, with the triple combination (B+Y+N) being particularly potent. Each tumor group alters the expression of thousands of B-,Y- and N-driven unique and common target genes. Identifying those most responsible for transformation is thus an important question as it might reveal new mechanistic insights and therapeutic opportunities. Approach and ResultsTranscriptional profiling of >60 murine HBs driven by the above oncogenic combinations and different B mutants and in genetic backgrounds that impair tumor growth rates but not initiation has revealed a common set of 22 "BYN genes" that are similarly deregulated in all cases. Many are associated with multiple "Cancer Hallmarks" and their expression levels often correlate with survival in human HBs, hepatocellular carcinomas and other cancers. Among the most down-regulated of these is Gas1, which encodes a Glycosylphosphatidylinositol (GPI)-linked outer membrane protein. We show here that restoring Gas1 expression impairs B+Y+N-driven HB tumor growth in vivo and in HB-derived immortalized cell lines in vitro in a manner than requires membrane anchoring of the protein via its GPI moiety. ConclusionsOur findings implicate Gas1 as a proximal mediator of HB pathogenesis and validate the BYN gene set as one deserving of closer additional scrutiny in future studies.

cancer biology↗

bioRxiv2024

Efficient Derivation of Immortalized, Isogenic Cell Lines from Genetically Defined Murine Hepatoblastomas

Background & AimsMolecularly, hepatoblastoma (HB), the most common childhood liver cancer, is the simplest of all human neoplasms, with the vast majority deregulating the Wnt/{beta}-catenin, Hippo and/or NFE2/NRF2 signaling pathways. Murine HBs can be generated by over-expressing any pairwise or triple combination of mutant forms of these pathways terminal effectors, namely {beta}-catenin (B), YAP (Y) and NFE2L2/NRF (N). Each molecular subtypes displays distinct features resembling those of human HBs. However, research has been hampered by a paucity of established cell lines of any species. MethodsWe show here that immortalized cell lines can be routinely established from murine HBs that over-express B+Y and B+Y+N. This is facilitated by the concurrent in vivo, Crispr-mediated inactivation of the Cdkn2a tumor suppressor locus. ResultsEight BY and 3 BYN cell lines have been generated and characterized and are available to the HB research community. Ten of these lines can be regrown as subcutaneous and metastatic lung tumors in the immuno-competent mice from which they originated while retaining their original histologic features. During maintenance as spheroids in vitro, or during in vivo propagation, tumor cells express endothelial cell markers, particularly in regions that are hypoxic and/or in proximity to incipient blood vessels. ConclusionsThe ability to generate isogenic HB cell lines with defined oncogenic drivers should facilitate studies that are best performed in vitro. The approach may also be useful for deriving HB cell lines associated with less common molecular drivers and from human tumors. SynopsisThe derivation of multiple immortalized murine hepatoblastoma cell lines driven by defined oncogenes is described. These lines are isogenic, retain their tumorigenicity in immuno-competent mice, readily form spheroids and express endothelial markers in response to hypoxia. They will allow studies that have heretofore been difficult or impossible to perform in vivo.

cancer biology↗