64 research outputs found
Normal and Malignant Germ Cell Development
All articles of this thesis are reproduced with kind permission. Permission is granted by Oxford Journals (chapter 2), John Wiley & Sons Ltd. on behalf of PathSoc. (chapters 3, 5 and 6), Elsevier (chapter 4, and Nature Publishing Group (chapter 7).Defining normal and malignant germ cell development
is crucial for understanding the biology and behaviour of germ cell
tumours. Germ cell tumours show significant similarities with
immature germ cells. Furthermore, treatment sensitivity of germ cell
tumours reflects the intrinsic characteristics of the cell of origin.
The aim of this thesis was to identify factors involved in the
development of normal and malignant human germ cells. The marker
profile of male and female germ cells during normal foetal
development was established and compared to the profile found in
dysgenetic gonads. Furthermore, the role of extracellular factors
like the microenvironment was addressed, and links between
pluripotency, cellular differentiation, and treatment response were
investigated.
A number of markers for early germ cells could be confirmed and
further characterized. From our results, we conclude that external
factors like cell-cell signalling create a niche that is essential to
ensure normal germ cell development.
The analyses were then extended to tissue samples showing delayed or
disturbed maturation. An amazing finding was the detection of germ
cell-lineage differentiation in nonseminomatous germ cell tumours.
Human germ cell tumours must therefore be regarded as truly
totipotent tumours with unrestricted developmental potential.
Finally, our investigations present findings of different factors
supposedly involved in chemotherapy resistance. Rather than being
involved in treatment resistance, several factors investigated were
found to be differentially regulated during germ cell development.
This illustrates that in germ cell tumours it is particularly
important to be able to interpret results in view of aspects of
developmental biology
Micro-RNA expression in cisplatin resistant germ cell tumor cell lines
<p>Abstract</p> <p>Background</p> <p>We compared microRNA expression patterns in three cisplatin resistant sublines derived from paternal cisplatin sensitive germ cell tumor cell lines in order to improve our understanding of the mechanisms of cisplatin resistance.</p> <p>Methods</p> <p>Three cisplatin resistant sublines (NTERA-2-R, NCCIT-R, 2102EP-R) showing 2.7-11.3-fold increase in drug resistance after intermittent exposure to increasing doses of cisplatin were compared to their parental counterparts, three well established relatively cisplatin sensitive germ cell tumor cell lines (NTERA-2, NCCIT, 2102EP). Cells were cultured and total RNA was isolated from all 6 cell lines in three independent experiments. RNA was converted into cDNA and quantitative RT-PCR was run using 384 well low density arrays covering almost all (738) known microRNA species of human origin.</p> <p>Results</p> <p>Altogether 72 of 738 (9.8%) microRNAs appeared differentially expressed between sensitive and resistant cell line pairs (NTERA-2R/NTERA-2 = 43, NCCIT-R/NCCIT = 53, 2102EP-R/2102EP = 15) of which 46.7-95.3% were up-regulated (NTERA-2R/NTERA-2 = 95.3%, NCCIT-R/NCCIT = 62.3%, 2102EP-R/2102EP = 46.7%). The number of genes showing differential expression in more than one of the cell line pairs was 34 between NTERA-2R/NTERA-2 (79%) and NCCIT-R/NCCIT (64%), and 3 and 4, respectively, between these two cell lines and 2102EP-R/2102EP (about 27%). Only the has-miR-10b involved in breast cancer invasion and metastasis and has-miR-512-3p appeared to be up-regulated (2-3-fold) in all three cell lines. The hsa-miR-371-373 cluster (counteracting cellular senescence and linked with differentiation potency), as well as hsa-miR-520c/-520h (inhibiting the tumor suppressor p21) were 3.9-16.3 fold up-regulated in two of the three cisplatin resistant cell lines. Several new micro-RNA species missing an annotation towards cisplatin resistance could be identified. These were hsa-miR-512-3p/-515/-517/-518/-525 (up to 8.1-fold up-regulated) and hsa-miR-99a/-100/-145 (up to 10-fold down-regulated).</p> <p>Conclusion</p> <p>Examining almost all known human micro-RNA species confirmed the miR-371-373 cluster as a promising target for explaining cisplatin resistance, potentially by counteracting wild-type P53 induced senescence or linking it with the potency to differentiate. Moreover, we describe for the first time an association of the up-regulation of micro-RNA species such as hsa-miR-512-3p/-515/-517/-518/-525 and down-regulation of hsa-miR-99a/-100/-145 with a cisplatin resistant phenotype in human germ cell tumors. Further functional analyses are warranted to gain insight into their role in drug resistance.</p
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A signaling cascade including ARID1A, GADD45B and DUSP1 induces apoptosis and affects the cell cycle of germ cell cancers after romidepsin treatment
In Western countries, the incidence of testicular germ cell cancers (GCC) is steadily rising over the last decades. Mostly, men between 20 and 40 years of age are affected. In general, patients suffering from GCCs are treated by orchiectomy and radio- or chemotherapy. Due to resistance mechanisms, intolerance to the therapy or denial of chemo- / radiotherapy by the patients, GCCs are still a lethal threat, highlighting the need for alternative treatment strategies. In this study, we revealed that germ cell cancer cell lines are highly sensitive to the histone deacetylase inhibitor romidepsin in vitro and in vivo, highlighting romidepsin as a potential therapeutic option for GCC patients. Romidepsin-mediated inhibition of histone deacetylases led to disturbances of the chromatin landscape. This resulted in locus-specific histone-hyper- or hypoacetylation. We found that hypoacetylation at the ARID1A promotor caused repression of the SWI/SNF-complex member ARID1A. In consequence, this resulted in upregulation of the stress-sensors and apoptosis-regulators GADD45B, DUSP1 and CDKN1A. RNAi-driven knock down of ARID1A mimicked in parts the effects of romidepsin, while CRISPR/Cas9-mediated deletion of GADD45B attenuated the romidepsin-provoked induction of apoptosis and cell cycle alterations. We propose a signaling cascade involving ARID1A, GADD45B and DUSP1 as mediators of the romidepsin effects in GCC cells
Anticancer Activity of the Marine Triterpene Glycoside Cucumarioside A-2 in Human Prostate Cancer Cells
Despite recent advances in the treatment of metastatic castration-resistant prostate cancer (CRPC), treatment is inevitably hampered by the development of drug resistance. Thus, new drugs are urgently needed. We investigated the efficacy, toxicity, and mechanism of action of the marine triterpene glycoside cucumarioside A-2 (CA-2) using an in vitro CRPC model. CA-2 induced a G/M-phase cell cycle arrest in human prostate cancer PC-3 cells and caspase-dependent apoptosis executed via an intrinsic pathway. Additionally, the drug inhibited the formation and growth of CRPC cell colonies at low micromolar concentrations. A global proteome analysis performed using the 2D-PAGE technique, followed by MALDI-MS and bioinformatical evaluation, revealed alterations in the proteins involved in cellular processes such as metastatic potential, invasion, and apoptosis. Among others, the regulation of keratin 81, CrkII, IL-1β, and cathepsin B could be identified by our proteomics approach. The effects were validated on the protein level by a 2D Western blotting analysis. Our results demonstrate the promising anticancer activity of CA-2 in a prostate cancer model and provide insights on the underlying mode of action
POU5F1 (OCT3/4) identifies cells with pluripotent potential in human germ cell tumors
Human germ cell tumors (GCTs) may have variable histology and clinical
behavior, depending on factors such as sex of the patient, age at clinical
diagnosis, and anatomical site of the tumor. Some types of GCT, i.e., the
seminomas/germinomas/dysgerminomas and embryonal carcinomas (the stem cell
component of nonseminomas), have pluripotent potential, which is
demonstrated by their capacity to differentiate into somatic and/or
extraembryonic elements. Although embryonal carcinoma cells are
intrinsically pluripotent, seminoma/germinoma/dysgerminoma cells, as well
as their precursor carcinoma in situ/gonadoblastoma cells, have the
phenotype of early germ cells that can be activated to pluripotency. The
other types of GCT (teratomas and yolk sac tumors of infants and newborn,
dermoid cyst of the ovary, and spermatocytic seminoma of elderly) are
composed of (fully) differentiated tissues and lack the appearance of
undifferentiated and pluripotent stem cells. OCT3/4, a transcription
factor also known as OTF3 and POU5F1, is involved in regulation of
pluripotency during normal development and is detectable in embryonic stem
and germ cells. We analyzed the presence of POU5F1 in GCT and other tumor
types using immunohistochemistry. The protein was consistently detected in
carcinoma in situ/gonadoblasto
Multi tyrosine kinase inhibitor dasatinib as novel cause of severe pre-capillary pulmonary hypertension?
<p>Abstract</p> <p>Background</p> <p>Pulmonary hypertension (PH) is a life-threatening disease with poor prognosis. Encouraging efforts have been made to target the main vasoproliferative aspects of the disease. Promising emerging therapeutics are tyrosine kinase inhibitors such as imatinib.</p> <p>Case presentation</p> <p>Here, we discuss the relevance of previously published cases and add another well-characterised patient who developed pre-capillary PH under long-term therapy with the multi-tyrosine kinase inhibitor dasatinib approved for therapy of chronic myeloic leukaemia (CML) and Philadelphia chromosome positive acute lymphocytic leukaemia (mean time of all patients on dasatinib: 26 months). Hence, we discuss the possibility of dasatinib itself causing PH after long-term therapy and turn specialist's attention to this possible severe side effect.</p> <p>At present, the true incidence of dasatinib-associated PH remains illusive and systematic data regarding haemodynamics are missing.</p> <p>Conclusion</p> <p>We therefore recommend systematic screening of dasatinib-treated patients for pulmonary hypertension and subsequent collection of haemodynamic data.</p
Marine Compounds and Cancer: Updates 2020
By the end of the year 2020, there are nine marine-derived anticancer drugs available on the market, and the field is currently growing exponentially [...
Marine Compounds and Cancer: 2017 Updates
By the end of 2017, there were seven marine-derived pharmaceutical substances that have been approved by the FDA for clinical use as drugs[...
Marine Compounds and Cancer: Where Do We Stand?
In Western countries, cancer is among the most frequent causes of death. Despite striking advances in cancer therapy, there is still an urgent need for new drugs in oncology. Current development favors so called “targeted agents” or drugs that target the immune system, i.e., therapeutic antibodies that enhance or facilitate an immune response against tumor cells (also referred to as “checkpoint inhibitors”). However, until recently, roughly 60% of drugs used in hematology and oncology were originally derived from natural sources, and one third of the top-selling agents are either natural agents or derivatives [1]. There is justified hope for the discovery and development of new anticancer agents from the marine environment. Historically, this habitat has proven to be a rich source of potent natural compounds such as alkaloids, steroids, terpenes, macrolides, peptides, and polyketides, among others. Interestingly, marine agents and cancer treatment have had a special relationship from the beginning. One of the first marine-derived compounds, discovered in 1945 that was later developed into a clinically used drug, was spongothymidine [2–4], which was the lead compound for the discovery of cytarabine [5]. Until today, cytarabine remains one of the most widely used agents in the treatment of acute myeloid leukemia and relapsed aggressive lymphomas. [...
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