Metastasis is the leading cause of morbidity for lung cancer patients. Here we demonstrate that murine tumor propagating cells (TPCs) with the markers Sca1 and CD24 are enriched for metastatic ...potential in orthotopic transplantation assays. CD24 knockdown decreased the metastatic potential of lung cancer cell lines resembling TPCs. In lung cancer patient data sets, metastatic spread and patient survival could be stratified with a murine lung TPC gene signature. The TPC signature was enriched for genes in the Hippo signaling pathway. Knockdown of the Hippo mediators Yap1 or Taz decreased in vitro cellular migration and transplantation of metastatic disease. Furthermore, constitutively active Yap was sufficient to drive lung tumor progression in vivo. These results demonstrate functional roles for two different pathways, CD24‐dependent and Yap/Taz‐dependent pathways, in lung tumor propagation and metastasis. This study demonstrates the utility of TPCs for identifying molecules contributing to metastatic lung cancer, potentially enabling the therapeutic targeting of this devastating disease.
Synopsis
The molecular characterization of tumor‐propagating cells in mouse models of lung cancer reveals CD24+/Sca1+ and increased Yap/Taz activity as predictive for tumor metastasis.
Murine lung TPCs with the markers Sca1 and CD24 are enriched for metastatic potential in orthotopic transplantation assays.
In lung cancer patient data sets, metastatic spread and patient survival could be stratified with a murine lung TPC gene signature.
Knockdown of the Hippo mediators Yap1 or Taz decreased migration and metastatic potential of lung cancer cells.
Yap activation was sufficient for driving tumor progression in the Kras mouse model of lung cancer.
The molecular characterization of tumor‐propagating cells in mouse models of lung cancer reveals CD24+/Sca1+ and increased Yap/Taz activity as predictive for tumor metastasis.
Successful cancer therapy requires the elimination or incapacitation of all tumor cells capable of regenerating a tumor. Therapeutic advances therefore necessitate the characterization of the cells ...that are able to propagate a tumor in vivo. We show an important link between tumor genotype and isolation of tumor-propagating cells (TPCs). Three mouse models of the most common form of human lung cancer each had TPCs with a unique cell-surface phenotype. The cell-surface marker Sca1 did not enrich for TPCs in tumors initiated with oncogenic Kras, and only Sca1-negative cells propagated EGFR mutant tumors. In contrast, Sca1-positive cells were enriched for tumor-propagating activity in Kras tumors with p53 deficiency. Primary tumors that differ in genotype at just one locus can therefore have tumor-propagating cell populations with distinct markers. Our studies show that the genotype of tumor samples must be considered in studies to identify, characterize, and target tumor-propagating cells.
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► Identification of the first lung tumor-propagating cell population ► Lung cancers of different genotype have tumor-propagating cells with distinct markers ► Tumor samples should be separated by genotype to study tumor-propagating cells
Lung cancer is notorious for its ability to metastasize, but the pathways regulating lung cancer metastasis are largely unknown. An in vitro system designed to discover factors critical for lung ...cancer cell migration identified brain-derived neurotrophic factor, which stimulates cell migration through activation of tropomyosin-related kinase B (TrkB; also called NTRK2). Knockdown of TrkB in human lung cancer cell lines significantly decreased their migratory and metastatic ability in vitro and in vivo. In an autochthonous lung adenocarcinoma model driven by activated oncogenic Kras and p53 loss, TrkB deficiency significantly reduced metastasis. Hypoxia-inducible factor-1 directly regulated TrkB expression, and, in turn, TrkB activated Akt signaling in metastatic lung cancer cells. Finally, TrkB expression was correlated with metastasis in patient samples, and TrkB was detected more often in tumors that did not have Kras or epidermal growth factor receptor mutations. These studies demonstrate that TrkB is an important therapeutic target in metastatic lung adenocarcinoma.
Generalized arterial calcification of infancy (GACI) is a rare, life-threatening disorder caused by loss-of-function mutations in the gene encoding ectonucleotide pyrophosphatase phosphodiesterase 1 ...(
), which normally hydrolyzes extracellular ATP into AMP and pyrophosphate (PP
). The disease is characterized by extensive arterial calcification and stenosis of large- and medium-sized vessels, leading to vascular-related complications of hypertension and heart failure. There is currently no effective treatment available, but bisphosphonates - nonhydrolyzable PP
analogs - are being used off-label to reduce arterial calcification, although this has no reported impact on the hypertension and cardiac dysfunction features of GACI. In this study, the efficacy of a recombinant human ENPP1 protein therapeutic (rhENPP1) was tested in
homozygous mice (
or
hom), a model previously described to show extensive mineralization in the arterial vasculature, similar to GACI patients. In a disease prevention study,
mice treated with rhENPP1 for 3 weeks showed >95% reduction in aorta calcification. Terminal hemodynamics and echocardiography imaging of
mice also revealed that a 6-week rhENPP1 treatment normalized elevated arterial and left ventricular pressure, which translated into significant improvements in myocardial compliance, contractility, heart workload and global cardiovascular efficiency. This study suggests that ENPP1 enzyme replacement therapy could be a more effective GACI therapeutic than bisphosphonates, treating not just the vascular calcification, but also the hypertension that eventually leads to cardiac failure in GACI patients.
Metastatic disease is the primary cause of death of patients with lung cancer, but the mouse models of lung adenocarcinoma do not accurately recapitulate the tumor microenvironment or metastatic ...disease observed in patients. In this study, we conditionally deleted E-cadherin in an autochthonous lung adenocarcinoma mouse model driven by activated oncogenic Kras and p53 loss. Loss of E-cadherin significantly accelerated lung adenocarcinoma progression and decreased survival of the mice. Kras;p53;E-cadherin mice had a 41% lung tumor burden, invasive grade 4 tumors, and a desmoplastic stroma just 8 weeks after tumor initiation. One hundred percent of the mice developed local metastases to the lymph nodes or chest wall, and 38% developed distant metastases to the liver or kidney. Lung adenocarcinoma cancer cell lines derived from these tumors also had high migratory rates. These studies demonstrate that the Kras;p53;E-cadherin mouse model better emulates the tumor microenvironment and metastases observed in patients with lung adenocarcinoma than previous models and may therefore be useful for studying metastasis and testing new lung cancer treatments in vivo.
RNASET2 deficiency in humans is associated with infant cystic leukoencephalopathy, which causes psychomotor impairment, spasticity and epilepsy. A zebrafish mutant model suggests that loss of RNASET2 ...function leads to neurodegeneration due to the accumulation of non-degraded RNA in the lysosomes. The goal of this study was to characterize the first rodent model of RNASET2 deficiency. The brains of 3- and 12-month-old
knockout rats were studied using multiple magnetic resonance imaging modalities and behavioral tests. While T1- and T2-weighted images of
knockout rats exhibited no evidence of cystic lesions, the prefrontal cortex and hippocampal complex were enlarged in knockout animals. Diffusion-weighted imaging showed altered anisotropy and putative gray matter changes in the hippocampal complex of the
knockout rats. Immunohistochemistry for glial fibrillary acidic protein (GFAP) showed the presence of hippocampal neuroinflammation. Decreased levels of lysosome-associated membrane protein 2 (LAMP2) and elevated acid phosphatase and β-N-acetylglucosaminidase (NAG) activities indicated that the
knockout rats likely had altered lysosomal function and potential defects in autophagy. Object recognition tests confirmed that
knockout rats exhibited memory deficits. However, the Barnes maze, and balance beam and rotarod tests indicated there were no differences in spatial memory or motor impairments, respectively. Overall, patients with RNASET2 deficiency exhibited a more severe neurodegeneration phenotype than was observed in the
knockout rats. However, the vulnerability of the knockout rat hippocampus as evidenced by neuroinflammation, altered lysosomal function and cognitive defects indicates that this is still a useful
model to study RNASET2 function.
Antibody–drug conjugates (ADCs) that incorporate the exatecan derivative DXd in their payload are showing promising clinical results in solid tumor indications. The payload has an F-ring that also ...contains a second chiral center, both of which complicate its synthesis and derivatization. Here we report on new camptothecin-ADCs that do not have an F-ring in their payloads yet behave similarly to DXd-bearing conjugates in vitro and in vivo. This simplification allows easier derivatization of camptothecin A and B rings for structure–activity relationship studies and payload optimization. ADCs having different degrees of bystander killing and the ability to release hydroxyl or thiol-bearing metabolites following peptide linker cleavage were investigated.
A disintegrin and metalloprotease (ADAM) 9 is a member of the ADAM family of multifunctional, multidomain type 1 transmembrane proteins. ADAM9 is overexpressed in many cancers, including non-small ...cell lung, pancreatic, gastric, breast, ovarian, and colorectal cancer, but exhibits limited expression in normal tissues. A target-unbiased discovery platform based on intact tumor and progenitor cell immunizations, followed by an immunohistochemistry screen, led to the identification of anti-ADAM9 antibodies with selective tumor-versus-normal tissue binding. Subsequent analysis revealed anti-ADAM9 antibodies were efficiently internalized and processed by tumor cells making ADAM9 an attractive target for antibody-drug conjugate development. Here, we describe the preclinical evaluation of IMGC936, a novel antibody-drug conjugate targeted against ADAM9. IMGC936 is comprised of a high-affinity humanized antibody site-specifically conjugated to DM21-C, a next-generation linker-payload that combines a maytansinoid microtubule-disrupting payload with a stable tripeptide linker, at a drug antibody ratio of approximately 2.0. Additionally, the YTE mutation (M252Y/S254T/T256E) was introduced into the CH2 domain of the antibody Fc to maximize in vivo plasma half-life and exposure. IMGC936 exhibited cytotoxicity toward ADAM9-positive human tumor cell lines, as well as bystander killing, potent antitumor activity in human cell line-derived xenograft and patient-derived xenograft tumor models, and an acceptable safety profile in cynomolgus monkeys with favorable pharmacokinetic properties. Our preclinical data provide a strong scientific rationale for the further development of IMGC936 as a therapeutic candidate for the treatment of ADAM9-positive cancers. A first-in-human study of IMGC936 in patients with advanced solid tumors has been initiated (NCT04622774).
Despite a good understanding of genes involved in oil biosynthesis in seed, the mechanism(s) that controls oil accumulation is still not known. To identify genes that control oil accumulation in ...seed, we have developed a simple screening method to isolate Arabidopsis seed oil mutants. The method includes an initial screen for seed density followed by a seed oil screen using an automated Nuclear Magnetic Resonance (NMR). Using this method, we isolated ten low oil mutants and one high oil mutant. The high oil mutant, p777, accumulated 8% more oil in seed than did wild type, but it showed no differences in seed size, plant growth or development. The high-oil phenotype is caused by the disruption of the GLABRA2 gene, a previously identified gene that encodes a homeobox protein required for normal trichome and root hair development. Knockout of GLABRA2 did not affect LEAFY COTYLEDON 1 and PICKLE expression in developing embryo. The result indicates that in addition to its known function in trichome and root hair development, GLABRA2 is involved in the control of seed oil accumulation.
Estrogen receptor-α (ERα) plays a critical role in male reproductive tract development and fertility. To determine whether estrogen-dependent and -independent ERα mechanisms are involved in male ...fertility, we examined male estrogen nonresponsive ERα knock-in mice. These animals have a point mutation (G525L) in the ligand-binding domain of ERα that significantly reduces interaction with, and response to, endogenous estrogens but does not affect growth factor activation of ligand-independent ERα pathways. Surprisingly, we found that ligand-independent ERα signaling is essential for concentrating epididymal sperm via regulation of efferent ductule fluid reabsorption. In contrast, estrogen-dependent ERα signaling is required for germ cell viability, most likely through support of Sertoli cell function. By treating estrogen nonresponsive ERα knock-in (ENERKI) mice with the ERα selective synthetic agonist propyl pyrazole triol, which is able to bind and activate G525L ERα in vivo, we discovered male fertility required neonatal estrogen-mediated ERα signaling. Thus, our work indicates both estrogen-dependent and -independent pathways play separable roles in male murine reproductive tract development and that the role of ERα in human infertility should be examined more closely.
Estrogen-dependent ERα signaling is required for germ cell viability, while estrogen-independent signaling is essential for concentrating epididymal sperm via regulation of efferent ductule fluid reabsorption.
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