SummaryFilamentous fungi are model microorganisms for studying nuclear migration in eukaryotic cells. Two genes, apsA and apsB (¼ anucleate primary sterigmata), were identified in Aspergillus nidulans that affect nuclear distribution in hyphae and specifically block conidiophore development at the metula stage when mutant. Here we describe the cloning, sequencing and molecular analysis of apsB. The gene encodes a 121 kDa coiled-coil, hydrophilic protein that was localized in the cytoplasm. No protein-protein interaction was detected between ApsB and ApsA, a membrane-associated, previously identified protein. An apsB null mutant was characterized by video epifluorescence microscopy using strains that express green fluorescent protein (GFP) in nuclei. With this novel approach, we have discovered a new mutant phenotype and have found that nuclei display an increased chaotic movement in older hyphal compartments that results in clustering and an uneven distribution of these organelles. These results suggest a regulatory role of ApsB in nuclear migration.
BackgroundTumor microenvironment-associated T cell senescence is a key limiting factor for durable effective cancer immunotherapy. A few studies have demonstrated the critical role of the tumor suppressor TP53-derived p53 isoforms in cellular senescence process of non-immune cells. However, their role in lymphocytes, in particular tumor-antigen (TA) specific T cells remain largely unexplored.MethodsHuman T cells from peripheral blood were retrovirally engineered to coexpress a TA-specific T cell receptor and the Δ133p53α-isoform, and characterized for their cellular phenotype, metabolic profile and effector functions.ResultsPhenotypic analysis of Δ133p53α-modified T cells revealed a marked reduction of the T-cell inhibitory molecules (ie, CD160 and TIGIT), a lower frequency of senescent-like CD57+ and CD160+ CD8+ T cell populations, and an increased number of less differentiated CD28+ T cells. Consistently, we demonstrated changes in the cellular metabolic program toward a quiescent T cell state. On a functional level, Δ133p53α-expressing T cells acquired a long-term proliferative capacity, showed superior cytokine secretion and enhanced tumor-specific killing in vitro and in mouse tumor model. Finally, we demonstrated the capacity of Δ133p53α to restore the antitumor response of senescent T cells isolated from multiple myeloma patients.ConclusionThis study uncovered a broad effect of Δ133p53α isoform in regulating T lymphocyte function. Enhancing fitness and effector functions of senescent T cells by modulation of p53 isoforms could be exploited for future translational research to improve cancer immunotherapy and immunosenescence-related diseases.
Background: Most childhood cancers occur sporadically and cannot be explained by an inherited mutation or an unhealthy lifestyle. This suggests other predisposition defects that may support the oncogenic transformation of cells, e.g. via impaired DNA-repair. Our study consequently aims to investigate the impact of increased methylation of intron 2 of RAD9A in cancer patients which may be associated with oncogenic transformation. Methods: We performed an epimutation screen of RAD9A and other candidate genes ( APC , CDKN2A , EFNA5 , and TP53 ) using bisulfite pyrosequencing and deep bisulfite sequencing (DBS) in skin fibroblasts of 20 patients with primary cancer in childhood and second primary cancer (2N) later in life, 20 matched patients with only one primary cancer (1N) in childhood and 20 matched cancer-free (0N) controls. Furthermore, we analyzed leukemia cancer samples, tumor cell lines, EBV lymphoblasts and FaDu subclones. Radiation, colony formation assays, cell proliferation, PCR and molecular karyotype SNP-array experiments were performed. Data were analyzed using the Kruskal-Wallis rank-sum test, Benjamini-Hochberg procedure, REML and R-scripts. Results: Four 1N patients and one 2N patient displayed elevated mean methylation levels (>10%) in intron 2 of RAD9A . DBS of RAD9A in these patients revealed >2% hypermethylated alleles consistent with relevant epimutations. We found RAD9A hypermethylation in the bone marrow of patients with pre-ALL (pre-acute lymphoblastic leukemia), AML (acute myeloid leukemia), NHL (non-Hodgkin lymphoma), PBL (plasmablastic lymphoma) and EBV-(Epstein Barr virus) transformed lymphoblastoid cells. Molecular karyotyping of AML samples with hypermethylated RAD9A showed an evolving duplication of 1.8 kb on Chr16p13.3 including the PKD1 gene. In generated FaDu subclones with hypermethylated RAD9A, we found a homozygous inactivation of CHD2, SPATA8 , SMARCA1 and a 302 kb duplication including genes deregulated in cancer. The detected aberrations proved to influence cell viability. RAD9A methylation was not affected by radiation or the chemotherapeutical daunorubicin.Conclusion: The analysis of patient samples, cell lines and subclones suggest a connection between methylation levels of the RAD9A intron 2 locus and inactivation or amplification of important genes and survival of the cells. We propose that RAD9A epimutations may have an impact on leukemia, tumorigenesis, cancer progression and can potentially serve as a valuable biomarker.
Treatment of first primary neoplasms (PN) in childhood with radiotherapy or chemotherapy is an established risk factor for second primary neoplasms (SN). In addition, there is growing evidence for this association from observational studies on ionizing radiation and cancer risk, in particular after radiation exposure in childhood. As only a subgroup of the treated children suffers from SN, other risk modifying factors (e.g. genetics) must be involved. We are conducting a case-control study with 600 anticipated participants to evaluate gene-radiation interactions and risk of SN (leukemia, thyroid or skin cancer) as well as PN (leukemia, lymphoma or CNS) with a new epidemiological design, in which we combine observational with experimental elements by analyzing gene expression in irradiated cultured human fibroblasts from skin biopsies. In a first step, we examine the participation proportions of survivors of childhood cancer with and without a SN and cancer free control patients (CO) from the department of accident surgery and orthopaedics. In addition to a skin biopsy of 3 mm and a saliva sample, we collect detailed questionnaire information on lifetime exposure to medical radiation and chemotherapy, socio-demographic factors, smoking, drinking, physical activity, medical history and family history of cancer and other diseases. Cases and controls will be matched by sex and age (1:1), and additionally among the former childhood cancer patients by type of the PN and year of first diagnosis (1 SN:3 PN). In explorative pilot experiments, we estimate gene expression differences by RNA-Seq in fibroblasts after low (0.05 Gy) and high (2 Gy) radiation doses at different time points (0.25 h, 2 h, 24 h). In the first recruitment drives of the ongoing study, we recruited 77 patients with SN and 95 matched patients with only one PN from 1975 eligible former childhood cancer patients at the German Childhood Cancer Registry, as well as 22 CO patients. Until November 2016, 33% of the contacted 231 SN patients, 20% of the 486 contacted PN patients and 69% of the 32 contacted CO patients participated in our study. Two hours after low and high in vitro radiation doses, the largest number of genes were differentially expressed, some of them only after high doses, some only after low doses and some after both. To our knowledge, the KIKME study is the first epidemiological project analyzing differential gene expression in primary fibroblasts before and after radiation with high and low doses to evaluate the potential genetic basis for emergence of a SN and a PN. However, the biological importance of the suggested differential gene expression after high and low doses of radiation has to be confirmed with the full study population. In addition, the gene expression must be analyzed in detail by group (SN, PN, CO) and will be combined with results from whole genome sequencing in order to obtain a comprehensive view of the role of radiation in the carcinogenesis of childhood cancer. Citation Format: Manuela Marron, Sebastian Zahnreich, Olesja Sinizyn, Heinz Schmidberger, Moritz Hess, Patricia Sadre Dadras, Iris Altebockwinkel, Thomas Hankeln, Steffen Rapp, Anne Ebersberger, Christian Grad, Eva Holzhäuser, Lukas Eckhard, Dirk Proschek, Maria Blettner, Peter Kaatsch, Claudia Spix, Danuta Galetzka, Harald Binder. Cancer in childhood and molecular epidemiology - The KIKME case-control study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4261. doi:10.1158/1538-7445.AM2017-4261
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