There is a clear need to expand the toolkit of adequate mouse models and cell lines available for preclinical studies of high-grade neuroendocrine lung carcinoma (small cell lung carcinoma (SCLC) and ...large cell neuroendocrine carcinoma (LCNEC)). SCLC and LCNEC are two highly aggressive tumor types with dismal prognoses and few therapeutic options. Currently, there is an extreme paucity of material, particularly in the case of LCNEC. Given the lack of murine cell lines and transplant models of LCNEC, the need is imperative. In this study, we generated and examined new models of LCNEC and SCLC transplantable cell lines derived from our previously developed primary mouse LCNEC and SCLC tumors. RNA-seq analysis demonstrated that our cell lines and syngeneic tumors maintained the transcriptome program from the original transgenic primary tumor and displayed strong similarities to human SCLC or LCNEC. Importantly, the SCLC transplanted cell lines showed the ability to metastasize and mimic this characteristic of the human condition. In summary, we generated mouse cell line tools that allow further basic and translational research as well as preclinical testing of new treatment strategies for SCLC and LCNEC. These tools retain important features of their human counterparts and address the lack of LCNEC disease models.
Hair follicle stem cells (HF-SCs) alternate between periods of quiescence and proliferation, to finally differentiate into all the cell types that constitute the hair follicle. Also, they have been ...recently identified as cells of origin in skin cancer. HF-SCs localize in a precise region of the hair follicle, the bulge, and molecular markers for this population have been established. Thus, HF-SCs are good model to study the potential role of oncogenic activations on SC physiology. Expression of a permanently active form of Akt (myrAkt) in basal cells leads to Akt hyperactivation specifically in the CD34(+)Itga6(H) population. This activation causes bulge stem cells to exit from quiescence increasing their response to proliferative stimuli and affecting some functions such as cell migration. HF-SC identity upon Akt activation is preserved; in this sense, increased proliferation does not result in stem cell exhaustion with age suggesting that Akt activation does not affect self-renewal an important aspect for normal tissue maintenance and cancer development. Genome-wide transcriptome analysis of HF-SC isolated from myrAkt and wild-type epidermis underscores changes in metabolic pathways characteristic of cancer cells. These differences manifest during a two-step carcinogenesis protocol in which Akt activation in HF-SCs results in increased tumor development and malignant transformation.
Pentraxin 3 (PTX3) is a fluid-phase pattern recognition receptor of the humoral innate immune system with ancestral antibody-like properties but unknown antibody-inducing function. In this study, we ...found binding of PTX3 to splenic marginal zone (MZ) B cells, an innate-like subset of antibody-producing lymphocytes strategically positioned at the interface between the circulation and the adaptive immune system. PTX3 was released by a subset of neutrophils that surrounded the splenic MZ and expressed an immune activation-related gene signature distinct from that of circulating neutrophils. Binding of PTX3 promoted homeostatic production of IgM and class-switched IgG antibodies to microbial capsular polysaccharides, which decreased in PTX3-deficient mice and humans. In addition, PTX3 increased IgM and IgG production after infection with blood-borne encapsulated bacteria or immunization with bacterial carbohydrates. This immunogenic effect stemmed from the activation of MZ B cells through a neutrophil-regulated pathway that elicited class switching and plasmablast expansion via a combination of T cell-independent and T cell-dependent signals. Thus, PTX3 may bridge the humoral arms of the innate and adaptive immune systems by serving as an endogenous adjuvant for MZ B cells. This property could be harnessed to develop more effective vaccines against encapsulated pathogens.
Fanconi anemia (FA) is a heritable malformation, bone marrow failure and cancer predisposition syndrome that confers an exceptionally high risk of squamous carcinomas. These carcinomas originate in ...epithelia lining the mouth, proximal esophagus, vulva and anus: their origins are not understood, and no effective ways have been identified to prevent or delay their appearance. Many FA‐associated carcinomas are also therapeutically challenging: they may be multi‐focal and stage‐advanced at diagnosis, and most individuals with FA cannot tolerate standard‐of‐care systemic therapies such as DNA cross‐linking drugs or ionizing radiation due to constitutional DNA damage hypersensitivity. We developed the Fanconi Anemia Cancer Cell Line Resource (FA‐CCLR) to foster new work on the origins, treatment and prevention of FA‐associated carcinomas. The FA‐CCLR consists of Fanconi‐isogenic head and neck squamous cell carcinoma (HNSCC) cell line pairs generated from five individuals with FA‐associated HNSCC, and five individuals with sporadic HNSCC. Sporadic, isogenic HNSCC cell line pairs were generated in parallel with FA patient‐derived isogenic cell line pairs to provide comparable experimental material to use to identify cell and molecular phenotypes driven by germline or somatic loss of Fanconi pathway function, and the subset of these FA‐dependent phenotypes that can be modified, complemented or suppressed. All 10 FANC‐isogenic cell line pairs are available to academic, non‐profit and industry investigators via the “Fanconi Anemia Research Materials” Resource and Repository at Oregon Health & Sciences University, Portland OR.
What's new?
People with Fanconi anemia are at high risk of squamous cell carcinomas (SCC), but it is not well understood how these cancers originate and there is no effective prevention strategy. Here, the authors describe a new tool for studying the origin, treatment and prevention of these carcinomas. The Fanconi Anemia Cancer Cell Line Resource consists of 10 new FANC‐isogenic cell line pairs generated from 5 people with FA‐associated head and neck SCC and 5 with sporadic HNSCC. These cell lines are available for distribution to investigators studying FA or sporadic HNSCC.
Neurons frequently show an imbalance in expression of the 3' untranslated region (3'UTR) relative to the coding DNA sequence (CDS) region of mature messenger RNAs (mRNA). The ratio varies among ...different cells or parts of the brain. The Map2 protein levels per cell depend on the 3'UTR-to-CDS ratio rather than the total mRNA amount, which suggests powerful regulation of protein expression by 3'UTR sequences. Here we found that MAPT (the microtubule-associated protein tau gene) 3'UTR levels are particularly high with respect to other genes; indeed, the 3'UTR-to-CDS ratio of MAPT is balanced in healthy brain in mouse and human. The tau protein accumulates in Alzheimer diseased brain. We nonetheless observed that the levels of RNA encoding MAPT/tau were diminished in these patients' brains. To explain this apparently contradictory result, we studied MAPT mRNA stoichiometry in coding and non-coding regions, and found that the 3'UTR-to-CDS ratio was higher in the hippocampus of Alzheimer disease patients, with higher tau protein but lower total mRNA levels. Our data indicate that changes in the 3'UTR-to-CDS ratio have a regulatory role in the disease. Future research should thus consider not only mRNA levels, but also the ratios between coding and non-coding regions.
Correction of mis-splicing events is a growing therapeutic approach for neurological diseases such as spinal muscular atrophy or neuronal ceroid lipofuscinosis 7, which are caused by ...splicing-affecting mutations. Non-mutation harboring mis-spliced effector genes are also good candidate therapeutic targets in diseases with more complex etiologies such as cancer, autism, muscular dystrophies or neurodegenerative diseases. Next-generation RNA sequencing (RNA-seq) has boosted investigation of global mis-splicing in diseased tissue to identify such key pathogenic mis-spliced genes. Nevertheless, while analysis of tumour or dystrophic muscle biopsies can be informative on early stage pathogenic mis-splicing, for neurodegenerative diseases, these analyses are intrinsically hampered by neuronal loss and neuroinflammation in post-mortem brains. To infer splicing alterations relevant to Huntington's disease (HD) pathogenesis, here we performed intersect-RNA-seq analyses of human post-mortem striatal tissue and of an early symptomatic mouse model in which neuronal loss and gliosis are not yet present. Together with a human/mouse parallel motif scan analysis, this approach allowed us to identify the shared mis-splicing signature triggered by the HD-causing mutation in both species and to infer upstream deregulated splicing factors. Moreover, we identified a plethora of downstream neurodegeneration-linked mis-spliced effector genes that -together with the deregulated splicing factors- become new possible therapeutic targets. In summary, here we report pathogenic global mis-splicing in HD striatum captured by our new intersect-RNA-seq approach that can be readily applied to other neurodegenerative diseases for which bona fide animal models are available.
The mechanisms by which mitochondrial metabolism supports cancer anabolism remain unclear. Here, we found that genetic and pharmacological inactivation of pyruvate dehydrogenase A1 (PDHA1), a subunit ...of the pyruvate dehydrogenase complex (PDC), inhibits prostate cancer development in mouse and human xenograft tumor models by affecting lipid biosynthesis. Mechanistically, we show that in prostate cancer, PDC localizes in both the mitochondria and the nucleus. Whereas nuclear PDC controls the expression of sterol regulatory element-binding transcription factor (SREBF)-target genes by mediating histone acetylation, mitochondrial PDC provides cytosolic citrate for lipid synthesis in a coordinated manner, thereby sustaining anabolism. Additionally, we found that PDHA1 and the PDC activator pyruvate dehydrogenase phosphatase 1 (PDP1) are frequently amplified and overexpressed at both the gene and protein levels in prostate tumors. Together, these findings demonstrate that both mitochondrial and nuclear PDC sustain prostate tumorigenesis by controlling lipid biosynthesis, thus suggesting this complex as a potential target for cancer therapy.
Prosenescence therapy has recently emerged as a novel therapeutic approach for treating cancer. However, this concept is challenged by conflicting evidence showing that the senescence-associated ...secretory phenotype (SASP) of senescent tumor cells can have pro- as well as antitumorigenic effects. Herein, we report that, in Pten-null senescent tumors, activation of the Jak2/Stat3 pathway establishes an immunosuppressive tumor microenvironment that contributes to tumor growth and chemoresistance. Activation of the Jak2/Stat3 pathway in Pten-null tumors is sustained by the downregulation of the protein tyrosine phosphatase PTPN11/SHP2, providing evidence for the existence of a novel PTEN/SHP2 axis. Importantly, treatment with docetaxel in combination with a JAK2 inhibitor reprograms the SASP and improves the efficacy of docetaxel-induced senescence by triggering a strong antitumor immune response in Pten-null tumors. Altogether, these data demonstrate that immune surveillance of senescent tumor cells can be suppressed in specific genetic backgrounds but also evoked by pharmacological treatments.
Oncogene-induced senescence (OIS) is a potent tumor suppressor mechanism. To identify senescence regulators relevant to cancer, we screened an shRNA library targeting genes deleted in hepatocellular ...carcinoma (HCC). Here, we describe how knockdown of the SWI/SNF component ARID1B prevents OIS and cooperates with RAS to induce liver tumors. ARID1B controls p16
and p21
transcription but also regulates DNA damage, oxidative stress, and p53 induction, suggesting that SWI/SNF uses additional mechanisms to regulate senescence. To systematically identify SWI/SNF targets regulating senescence, we carried out a focused shRNA screen. We discovered several new senescence regulators, including ENTPD7, an enzyme that hydrolyses nucleotides. ENTPD7 affects oxidative stress, DNA damage, and senescence. Importantly, expression of ENTPD7 or inhibition of nucleotide synthesis in ARID1B-depleted cells results in re-establishment of senescence. Our results identify novel mechanisms by which epigenetic regulators can affect tumor progression and suggest that prosenescence therapies could be employed against SWI/SNF-mutated cancers.
Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide, and although new therapeutic approaches have been recently evaluated, overall patient survival is still poor. ...Thus, new effective and selective clinical treatments are urgently needed. An analysis of data from large-scale, high-throughput drug screening cell line projects identified Bosutinib, a Src/Abl inhibitor that is currently used for the treatment of chronic myelogenous leukemia, as a candidate drug to treat HNSCC. Using a panel of HNSCC-derived cell lines, we found that treatment with Bosutinib reduced cell proliferation and induced apoptosis of sensitive cell lines. The drug rapidly inhibited Src and EGFR (epidermal growth factor receptor) phosphorylation, and sensitivity to Bosutinib was correlated with the activation status of EGFR. Similar findings were observed in in vivo xenograft assays using HNSCC derived cells. Moreover, in the presence of mutations in
, the combination of Bosutinib with the PI3Kα inhibitor Alpelisib showed a synergistic effect. These results suggest that Bosutinib could be a new effective drug for the treatment of HNSCC, particularly in tumors with high EGFR activity. Its combination with Alpelisib could especially benefit patients bearing activating mutations of
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