The foundational framework of tumors: Gametogenesis, p53, and cancer

The completion-of-tumor hypothesis involved in the dynamic interplay between the initiating oncogenic event and progression is essential to better recognize the foundational framework of tumors. Here we review and extend the gametogenesis-related hypothesis of tumors, because high embryonic/germ cell traits are common in tumors. The century-old gametogenesis-related hypothesis of tumors postulated that tumors arise from displaced/activated trophoblasts, displaced (lost) germ cells, and the reprogramming/reactivation of gametogenic program in somatic cells. Early primordial germ cells (PGCs), embryonic stem (ES) cells, embryonic germ cells (EGCs), and pre-implantation embryos at the stage from two-cell stage to blastocysts originating from fertilization or parthenogenesis have the potential to develop teratomas/teratocarcinomas. In addition, the teratomas/teratocarcinomas/germ cells occur in gonads and extra-gonads. Undoubtedly, the findings provide strong support for the hypothesis. However, it was thought that these tumor types were an exception rather than verification. In fact, there are extensive similarities between somatic tumor types and embryonic/germ cell development, such as antigens, migration, invasion, and immune escape. It was documented that embryonic/germ cell genes play crucial roles in tumor behaviors, e.g. tumor initiation and metastasis. Of note, embryonic/germ cell-like tumor cells at different developmental stages including PGC and oocyte to the early embryo-like stage were identified in diverse tumor types by our group. These embryonic/germ cell-like cancer cells resemble the natural embryonic/germ cells in morphology, gene expression, the capability of teratoma formation, and the ability to undergo the process of oocyte maturation and parthenogenesis. These embryonic/germ cell-like cancer cells are derived from somatic cells and contribute to tumor formation, metastasis, and drug resistance, establishing asexual meiotic embryonic life cycle. p53 inhibits the reactivation of embryonic/germ cell state in somatic cells and oocyte-like cell maturation. Based on earlier and our recent studies, we propose a novel model to complete the gametogenesis-related hypothesis of tumors, which can be applied to certain somatic tumors. That is, tumors tend to establish a somatic asexual meiotic embryonic cycle through the activation of somatic female gametogenesis and parthenogenesis in somatic tumor cells during the tumor progression, thus passing on corresponding embryonic/germ cell traits leading to the malignant behaviors and enhancing the cells' independence. This concept may be instrumental to better understand the nature and evolution of tumors. We rationalize that targeting the key events of somatic pregnancy is likely a better therapeutic strategy for cancer treatment than directly targeting cell mitotic proliferation, especially for those tumors with p53 inactivation.

Selective elimination of pluripotent stem cells by PIKfyve specific inhibitors

Inhibition of PIKfyve phosphoinositide kinase selectively kills autophagy-dependent cancer cells by disrupting lysosome homeostasis. Here, we show that PIKfyve inhibitors can also selectively eliminate pluripotent embryonal carcinoma cells (ECCs), embryonic stem cells, and induced pluripotent stem cells under conditions where differentiated cells remain viable. PIKfyve inhibitors prevented lysosome fission, induced autophagosome accumulation, and reduced cell proliferation in both pluripotent and differentiated cells, but they induced death only in pluripotent cells. The ability of PIKfyve inhibitors to distinguish between pluripotent and differentiated cells was confirmed with xenografts derived from ECCs. Pretreatment of ECCs with the PIKfyve specific inhibitor WX8 suppressed their ability to form teratocarcinomas in mice, and intraperitoneal injections of WX8 into mice harboring teratocarcinoma xenografts selectively eliminated pluripotent cells. Differentiated cells continued to proliferate, but at a reduced rate. These results provide a proof of principle that PIKfyve specific inhibitors can selectively eliminate pluripotent stem cells in vivo as well as in vitro.

A Novel Artificially Humanized Anti-Cripto-1 Antibody Suppressing Cancer Cell Growth

Cripto-1 is a member of the EGF-CFC/FRL1/Cryptic family and is involved in embryonic development and carcinogenesis. We designed a novel anti-Cripto-1 artificial antibody and assessed the recognition to the antigen and the potential to suppress the growth of cancer stem cells. First, single chain antibody clones were isolated by bio-panning with the affinity to recombinant Cripto-1 protein from our original phage-display library. Then, the variable regions of heavy chain VH and light chain VL in each clone were fused to constant regions of heavy chain CH and light chain CL regions respectively. These fused genes were expressed in ExpiCHO-S cells to produce artificial humanized antibodies against Cripto-1. After evaluation of the expression levels, one clone was selected and the anti-Cripto-1 antibody was produced and purified. The purified antibody showed affinity to recombinant Cripto-1 at 1.1 pmol and immunoreactivity to cancer tissues and cell lines. The antibody was available to detect the immunoreactivity in tissue microarrays of malignant tumors as well as in Cripto-1 overexpressing cells. Simultaneously, the antibody exhibited the potential to suppress the growth of human colon cancer derived GEO cells overexpressing Cripto-1 with IC₅₀ at approximately 110 nM. The artificially humanized antibody is proposed to be a good candidate to target cancer cells overexpressing Cripto-1.

TGFβ Family Signaling Pathways in Pluripotent and Teratocarcinoma Stem Cells' Fate Decisions: Balancing Between Self-Renewal, Differentiation, and Cancer

The transforming growth factor-β (TGFβ) family factors induce pleiotropic effects and are involved in the regulation of most normal and pathological cellular processes. The activity of different branches of the TGFβ family signaling pathways and their interplay with other signaling pathways govern the fine regulation of the self-renewal, differentiation onset and specialization of pluripotent stem cells in various cell derivatives. TGFβ family signaling pathways play a pivotal role in balancing basic cellular processes in pluripotent stem cells and their derivatives, although disturbances in their genome integrity induce the rearrangements of signaling pathways and lead to functional impairments and malignant transformation into cancer stem cells. Therefore, the identification of critical nodes and targets in the regulatory cascades of TGFβ family factors and other signaling pathways, and analysis of the rearrangements of the signal regulatory network during stem cell state transitions and interconversions, are key issues for understanding the fundamental mechanisms of both stem cell biology and cancer initiation and progression, as well as for clinical applications. This review summarizes recent advances in our understanding of TGFβ family functions in naїve and primed pluripotent stem cells and discusses how these pathways are involved in perturbations in the signaling network of malignant teratocarcinoma stem cells with impaired differentiation potential.

The HERV-K accessory protein Np9 controls viability and migration of teratocarcinoma cells

Human endogenous retroviruses are remnants of ancient germline infections that make up approximately 8% of the modern human genome. The HERV-K (HML-2) family is one of the most recent entrants into the human germline, these viruses appear to be transcriptionally active, and HERV-K viral like particles (VLPs) are found in cell lines from a number of human malignancies. HERV-K VLPs were first found to be produced in teratocarcinoma cell lines, and since then teratocarcinoma has been thought of as the classical model for HERV-Ks, with the NCCIT teratocarcinoma cell line particularly known to produce VLPs. Treatment for teratocarcinoma has progressed since its discovery, with improved prognosis for patients. Since the introduction of platinum based therapy, first year survival has greatly improved even with disseminated disease; however, it is estimated that 20% to 30% of patients present with metastatic germ cell tumor relapse following initial treatments. Also, the toxicity associated with the use of chemotherapeutic agents used to treat germ cell tumors is still a major concern. In this study, we show that the depletion of the HERV-K accessory protein Np9 increases the sensitivity of NCCIT teratocarcinoma cells to bleomycin and cisplatin. While decreasing the expression of Np9 had only a modest effect on the baseline viability of the cells, the reduced expression of Np9 increased the sensitivity of the teratocarcinoma cells to environmental (serum starvation) and chemical (chemotherapeutic) stresses. Np9 is also essential to the migration of NCCIT teratocarcinoma cells: in a wound closure assay, reduced expression of Np9 resulted in cells migrating into the wound at a slower rate, whereas reintroduction of Np9 resulted in NCCIT cells migrating back into the wound in a manner similar to the control. These findings support the implication that the HERV-K accessory protein Np9 has oncogenic potential.

WKY/Ztm-ter: a new rat inbred strain on the WKY/Ztm genetic background with congenital teratomas

We describe a new rat model for teratomas (WKY/Ztm- ter) which arose through a spontaneous mutation in the inbred WKY/Ztm rat strain. When the tumours of the gonads became clinically apparent, affected males were 14 to 224 days of age, whereas the females only developed tumours between days 21 and 63. Tumour incidence is not gender-dependent. However, almost all females develop bilateral tumours, while 50% of the males show unilateral tumours. Histologically, all examined tumours ( n = 65) represent partially undifferentiated teratocarcinomas.

Tumor-Free Transplantation of Patient-Derived Induced Pluripotent Stem Cell Progeny for Customized Islet Regeneration

Human induced pluripotent stem cells (iPSCs) and derived progeny provide invaluable regenerative platforms, yet their clinical translation has been compromised by their biosafety concern. Here, we assessed the safety of transplanting patient-derived iPSC-generated pancreatic endoderm/progenitor cells. Transplantation of progenitors from iPSCs reprogrammed by lentiviral vectors (LV-iPSCs) led to the formation of invasive teratocarcinoma-like tumors in more than 90% of immunodeficient mice. Moreover, removal of primary tumors from LV-iPSC progeny-transplanted hosts generated secondary and metastatic tumors. Combined transgene-free (TGF) reprogramming and elimination of residual pluripotent cells by enzymatic dissociation ensured tumor-free transplantation, ultimately enabling regeneration of type 1 diabetes-specific human islet structures in vivo. The incidence of tumor formation in TGF-iPSCs was titratable, depending on the oncogenic load, with reintegration of the cMYC expressing vector abolishing tumor-free transplantation. Thus, transgene-free cMYC-independent reprogramming and elimination of residual pluripotent cells are mandatory steps in achieving transplantation of iPSC progeny for customized and safe islet regeneration in vivo.

SIGNIFICANCE

Pluripotent stem cell therapy for diabetes relies on the safety as well as the quality of derived insulin-producing cells. Data from this study highlight prominent tumorigenic risks of induced pluripotent stem cell (iPSC) products, especially when reprogrammed with integrating vectors. Two major underlying mechanisms in iPSC tumorigenicity are residual pluripotent cells and cMYC overload by vector integration. This study also demonstrated that combined transgene-free reprogramming and enzymatic dissociation allows teratoma-free transplantation of iPSC progeny in the mouse model in testing the tumorigenicity of iPSC products. Further safety assessment and improvement in iPSC specification into a mature β cell phenotype would lead to safe islet replacement therapy for diabetes.

Prenatal diagnosis and outcomes of fetal teratomas

PURPOSE

Our aim was to evaluate the diagnostic performance of ultrasonography (US) in the prenatal identification of teratomas and the perinatal outcome of the fetuses with those teratomas.

METHODS

In this retrospective case series study, we searched the archives using the keywords "fetal mass" or "fetal tumor" or "fetal teratoma" and "sacrococcygeal teratoma," diagnosed between 2009 and 2014, within the US database of our center.

RESULTS

One hundred seven fetuses were prenatally diagnosed as having a cystic or solid mass, tumor, or teratoma. Nineteen of those cases were diagnosed prenatally as having fetal teratoma, but that diagnosis could not be verified in three cases. In one fetus, the prenatal diagnosis could not be confirmed. The sensitivity of US in identifying fetal teratoma was 100% and the false-positive rate, 3.3%. Six pregnancies complicated by a fetal teratoma were terminated. A normal karyotype was identified in all fetuses that underwent karyotyping. Among the nine women who continued their pregnancy, polyhydramnios was identified in four fetuses; although high-output heart failure was also identified in two of those fetuses during prenatal follow-up, none developed hydrops. On delivery, nine infants were born alive, but three (33.3%) of them died within the early neonatal period.

CONCLUSIONS

US has very high sensitivity and low false-positive rates in identifying fetal teratoma prenatally. The risk of chromosomal abnormalities is very low in fetuses with teratoma, and their prognosis depends on the location and size of the tumor and any associated perinatal complications.

Surrounding cells affect the gene expression pattern of human beta-defensins in squamous cell carcinoma in vitro

BACKGROUND/AIM

Defensins are basic peptides involved in non-immune bio-defense mechanisms in a normal epithelium. Human oral squamous cell carcinoma cells (OSCC) also produce human beta-defensins (HBDs), although their exact function is not clear. This study aimed to analyze the variation in gene expression levels of hBDs in co-cultures of OSCC with murine cells.

MATERIALS AND METHODS

Two OSCC cell lines (HSC-3, HSC-4) were co-cultured with mouse embryonic fibroblasts, NIH/3T3 or a mouse chondrogenic cell line derived from teratocarcinoma, ATDC5, for 1.5 days. Expression patterns of the hBD genes were investigated by real-time polymerase chain reaction (RT-PCR).

RESULTS

hBD1 expression increased when co-cultured with NIH/3T3 but decreased when co-cultured with ATDC5. Expression of hBD2 and hBD4 tended to decrease. OSCC cells formed colonies when co-cultured with NIH/3T3 but were scattered when co-cultured with ATDC5.

CONCLUSION

hBDs expression in OSCC is dependent on the type of co-cultured cells and differences in gene expression may be responsible for the morphological differences observed. OSCC may produce HBDs for purposes other than bio-defense by surrounding cells.

Effects of copper overload in P19 neurons: impairment of glutathione redox homeostasis and crosstalk between caspase and calpain protease systems in ROS-induced apoptosis

Copper, a transition metal with essential biological functions, exerts neurotoxic effects when present in excess. The aim of the present study was to better elucidate cellular and molecular mechanisms of CuSO4 toxicity in differentiated P19 neurons. Exposure to 0.5 mM CuSO4 for 24 h provoked moderate decrease in viability, accompanied with barely increased generation of reactive oxygen species (ROS) and caspase-3/7 activity. Glutathione (GSH) and ATP contents were depleted, lactate dehydrogenase inactivated, and glyceraldehyde-3-phosphate dehydrogenase overexpressed. In severely damaged neurons exposed to only two times higher concentration, classical caspase-dependent apoptosis was triggered as evidenced by marked caspase-3/7 activation and chromatin condensation. Multifold increase in ROS, together with very pronounced ATP and GSH loss, strongly suggests impairment of redox homeostasis. At higher copper concentration protease calpains were also activated, and neuronal injury was prevented in the presence of calpain inhibitor leupeptin through the mechanism that affects caspase activation. MK-801 and nifedipine, inhibitors of calcium entry, and H-89 and UO126, inhibitors of PKA and ERK signaling respectively, exacerbated neuronal death only in severely damaged neurons, while ROS-scavenger quercetin and calcium chelator BAPTA attenuated toxicity only at lower concentration. In a dose-dependent manner copper also provoked transcriptional changes of genes involved in intracellular signaling and induction of apoptosis (p53, c-fos, Bcl-2 and Bax). The obtained results emphasize differences in triggered neuronal-death processes in a very narrow range of concentrations and give further insight into the molecular mechanisms of copper toxicity with the potential to improve current therapeutic approaches in curing copper-related neurodegenerative diseases.

[Low expression of activin A in mouse and human embryonic teratocarcinoma cells]

TGFP3 family factors play an important role in regulating the balance of self-renewal and differentiation of mouse and human pluripotent stem and embryonic teratocarcinoma cells. The expression patterns of TGFbeta family signaling ligands and functional roles of these signaling pathways differ significantly in mouse and human embryonic stem cells, but the activity and functional role of these factors in mouse and human embryonic teratocarcinoma cells were not sufficiently investigated. Comparative quantitative real-time PCR analysis of the expression of TGF@[beta] family factors in mouse embryonic stem, embryonic germ, and embryonic teratocarcinoma cells showed that embryonic teratocarcinoma cells express lower ActivinA than pluripotent stem cells but similar levels of factors Nodal, Lefty 1, TGFbeta1, BMP4, and GDF3. In human nullipotent embryonic teratocarcinoma PA-1 cells, most factors of the TGFbeta family (ACTIVINA, NODAL, LEFTY 1, BMP4, and GDF3) are expressed at lower levels than in human embryonic stem cells: Thus, in mouse and human nullipotent teratocarcinoma cells, theexpression of ActivinA is significantly reduced com- pared ivith embryonic stem cells. Presumably, these differences may be associated with changes in the functional activity of the respective signaling pathways and deregulation of proliferative and antiproliferative mechanisms in embryonic teratocarcinoma cells.

Aza-deoxycytidine induces apoptosis or differentiation via DNMT3B and targets embryonal carcinoma cells but not their differentiated derivatives

BACKGROUND

Teratocarcinoma is a malignant male germ cell tumour, which contains stem cells and differentiated cancer tissues. DNMT3B has been shown to be highly expressed in human teratocarcinoma stem cells, and to mediate cytotoxicity of Aza-deoxycytidine (Aza-dC) in a pluripotent stem cell line NTERA2.

METHODS

We have established DNMT3B or POU5F1 (hereafter referred to as OCT4) knockdown in teratocarcinoma stem cells N2102Ep and TERA1 and in the pluripotent NTERA2 by a doxycycline-inducible system, and tested the cytotoxicity induced by Aza-dC.

RESULTS

Silencing of DNMT3B led to apoptosis of human teratocarcinoma stem cells N2102Ep and TERA1. Further, we found that induction of apoptosis or differentiation in NTERA2 and human embryonic stem cells by Aza-dC requires DNMT3B. To test whether Aza-dC inhibits proliferation of differentiated teratocarcinoma cells, we depleted OCT4 expression in N2102Ep and TERA1 cells treated with Aza-dC. Treatment with Aza-dC reduced cell number of differentiated cells to a lesser extent than their undifferentiated parental stem cells. Moreover, in contrast to the stem cells, Aza-dC failed to induce apoptosis of differentiated cells.

CONCLUSIONS

Our finding suggests that DNMT3B acts as an antiapoptotic gene in teratocarcinoma stem cells, and mediates apoptosis and differentiation of human pluripotent stem cells induced by Aza-dC, and that Aza-dC specifically induces apoptosis of teratocarcinoma stem cells.

Extra cellular matrix derived metabolite regulates angiogenesis by FasL mediated apoptosis

Object

Antiangiogenic treatments are beginning to give promising outcomes in many vascular diseases including tumor angiogenesis. In this current study the antiangiogenic and pro-apoptotic actions of α1(IV)NC1 and its N- and C- peptides α1S1(IV)NC1, α1S2(IV)NC1 were investigated in-vitro and in-vivo.

Study Method

Endothelial cells (ECs) were treated with α1(IV)NC1, α1S1(IV)NC1, α1S2(IV)NC1 and in-vitro proliferation, migration, tube formation and apoptotic assays were executed. FasL, Fas, Caspase-8, -3 and PARP activations were studied using immunoblotting analysis using specific antibodies. Also the in-vivo antiangiogenic and pro-apoptotic effects were tested using α1(IV)NC1 in a mice model.

Results

Like α1(IV)NC1, its N- and C- terminal α1S2(IV)NC1 and α1S1(IV)NC1 domains posses anti-proliferative, pro-apoptotic activity and inhibit ECs migration and tube formation in-vitro. Both α1S1(IV)NC1 and α1S2(IV)NC1 domains promote apoptosis by activating FasL and down stream apoptotic events including activation of caspase-8, -3 and PARP cleavage in a dose dependent manner in-vitro in ECs. Tumors in mice showed apoptotic TUNEL positive microvasculature upon α1(IV)NC1 treatment, indicating inhibition of tumor angiogenesis and tumor growth. Further, the antitumor activity of α1(IV)NC1 was abrogated when caspase-3 inhibitor was used. These results conform additional properties of α1(IV)NC1 as an endogenous angioinhibitor that induces apoptosis in-vitro and in-vivo by activating FasL mediated caspase-3.

Significance

α1(IV)NC1 and its N- and C- terminal α1S1(IV)NC1 and α1S2(IV)NC1 domains also posses pro-apoptotic and angioinhibitory activity in-vitro and in-vivo. α1(IV)NC1 regulates tumor angiogenesis by activating FasL mediated apoptosis in-vitro and in-vivo. These results demonstrate that α1(IV)NC1 and its peptides inhibit neo-vascular diseases.

αB-Crystallin regulates expansion of CD11b⁺Gr-1⁺ immature myeloid cells during tumor progression

The molecular chaperone αB-crystallin has emerged as a target for cancer therapy due to its expression in human tumors and its role in regulating tumor angiogenesis. αB-crystallin also reduces neuroinflammation, but its role in other inflammatory conditions has not been investigated. Here, we examined whether αB-crystallin regulates inflammation associated with tumors and ischemia. We found that CD45(+) leukocyte infiltration is 3-fold increased in tumors and ischemic myocardium in αB-crystallin-deficient mice. Notably, αB-crystallin is prominently expressed in CD11b(+) Gr-1(+) immature myeloid cells (IMCs), known as regulators of angiogenesis and immune responses, while lymphocytes and mature granulocytes show low αB-crystallin expression. αB-Crystallin deficiency results in a 3-fold higher accumulation of CD11b(+) Gr-1(+) IMCs in tumors and a significant rise in CD11b(+) Gr-1(+) IMCs in spleen and bone marrow. Similarly, we noted a 2-fold increase in CD11b(+) Gr-1(+) IMCs in chronically inflamed livers in αB-crystallin-deficient mice. The effect of αB-crystallin on IMC accumulation is limited to pathological conditions, as CD11b(+) Gr-1(+) IMCs are not elevated in naive mice. Through ex vivo differentiation of CD11b(+) Gr-1(+) cells, we provide evidence that αB-crystallin regulates systemic expansion of IMCs through a cell-intrinsic mechanism. Our study suggests a key role of αB-crystallin in limiting expansion of CD11b(+) Gr-1(+) IMCs in diverse pathological conditions.

Murine teratocarcinoma-derived neuronal cultures

This chapter describes the culture and propagation of murine embryonic stem cells, F9 and P19 and strategies for differentiation of these stem cells into neurons. Protocols focus on maintenance and propagation of these cells and routine procedures employed for differentiation into neuronal cells. Additional protocols are also described for obtaining enriched populations of mature neurons from P19 cells and differentiation of F9 cells into serotonergic or catecholaminergic neurons.The protocols described herein can be employed for dissection of the pathways such as gliogenesis and neurogenesis that are involved in differentiation of pluripotent stem cells such as F9 and P19 into glial cells or terminally differentiated neurons.

Regional differentiation of retinoic acid-induced human pluripotent embryonic carcinoma stem cell neurons

The NTERA2 cl D1 (NT2) cell line, derived from human teratocarcinoma, exhibits similar properties as embryonic stem (ES) cells or very early neuroepithelial progenitors. NT2 cells can be induced to become postmitotic central nervous system neurons (NT2N) with retinoic acid. Although neurons derived from pluripotent cells, such as NT2N, have been characterized for their neurotransmitter phenotypes, their potential suitability as a donor source for neural transplantation also depends on their ability to respond to localized environmental cues from a specific region of the CNS. Therefore, our study aimed to characterize the regional transcription factors that define the rostocaudal and dorsoventral identity of NT2N derived from a monolayer differentiation paradigm using quantitative PCR (qPCR). Purified NT2N mainly expressed both GABAergic and glutamatergic phenotypes and were electrically active but did not form functional synapses. The presence of immature astrocytes and possible radial glial cells was noted. The NT2N expressed a regional transcription factor code consistent with forebrain, hindbrain and spinal cord neural progenitors but showed minimal expression of midbrain phenotypes. In the dorsoventral plane NT2N expressed both dorsal and ventral neural progenitors. Of major interest was that even under the influence of retinoic acid, a known caudalization factor, the NT2N population maintained a rostral phenotype subpopulation which expressed cortical regional transcription factors. It is proposed that understanding the regional differentiation bias of neurons derived from pluripotent stem cells will facilitate their successful integration into existing neuronal networks within the CNS.

Sequential X-irradiation induced acquired resistance to oxaliplatin but increased sensitivity to cisplatin in two human teratoma cell lines in vitro

Cisplatin (CDDP) and oxaliplatin (OXA-P) are potential therapeutic drugs in the treatment of testicular cancer. However, the emergence of drug resistance has been documented not only in patients after chemotherapy but also subsequently to fractionated X-irradiation. Specific radiation-induced biochemical alterations may play a role in the observed resistance. Since irradiation influences the cellular responses to chemotherapy, this study investigated changes in the expression of key proteins in the regulation of DNA repair and apoptosis subsequent to sequential irradiation.

MATERIALS AND METHODS

Logarithmically growing human teratocarcinoma cell lines 2101 EP and H 12.1 were irradiated (10 fractions of 4 Gy in vitro) to establish the sub-lines 2101 EP/DXR-10 and H 12.1/DXR-10. Radiosensitivity was assayed using a clonogenic survival assay. Drug response was assayed using a sulforhodamine B assay. Expression of p53, PARP, hMSH2 and Fas was detected by Western blotting.

RESULTS

Both DXR-10 sub-lines showed a significant increase in sensitivity towards CDDP as compared to their parental cell line, however, there was a concomitant increase in resistance against OXA-P. No significant changes in radiosensitivity between parental and DXR-10 cell lines were observed. In addition, there was an up-regulation of PARP, p53, hMSH2 and Fas in the DXR-10 sub-lines, implicating induced damage tolerance and repair mechanisms following irradiation.

CONCLUSION

These results suggest that radiation preceding chemotherapy might induce resistance to subsequent chemotherapy with oxaliplatin but not to cisplatin. This is a novel observation and, if confirmed, particularly in other tumor types, may have clinical implications.

On the stem cell origin of cancer

In each major theory of the origin of cancer-field theory, chemical carcinogenesis, infection, mutation, or epigenetic change-the tissue stem cell is involved in the generation of cancer. Although the cancer type is identified by the more highly differentiated cells in the cancer cell lineage or hierarchy (transit-amplifying cells), the property of malignancy and the molecular lesion of the cancer exist in the cancer stem cell. In the case of teratocarcinomas, normal germinal stem cells have the potential to become cancers if placed in an environment that allows expression of the cancer phenotype (field theory). In cancers due to chemically induced mutations, viral infections, somatic and inherited mutations, or epigenetic changes, the molecular lesion or infection usually first occurs in the tissue stem cells. Cancer stem cells then give rise to transit-amplifying cells and terminally differentiated cells, similar to what happens in normal tissue renewal. However, the major difference between cancer growth and normal tissue renewal is that whereas normal transit amplifying cells usually differentiate and die, at various levels of differentiation, the cancer transit-amplifying cells fail to differentiate normally and instead accumulate (ie, they undergo maturation arrest), resulting in cancer growth.

A teratocarcinoma-like human embryonic stem cell (hESC) line and four hESC lines reveal potentially oncogenic genomic changes

The first Swiss human embryonic stem cell (hESC) line, CH-ES1, has shown features of a malignant cell line. It originated from the only single blastomere that survived cryopreservation of an embryo, and it more closely resembles teratocarcinoma lines than other hESC lines with respect to its abnormal karyotype and its formation of invasive tumors when injected into SCID mice. The aim of this study was to characterize the molecular basis of the oncogenicity of CH-ES1 cells, we looked for abnormal chromosomal copy number (by array Comparative Genomic Hybridization, aCGH) and single nucleotide polymorphisms (SNPs). To see how unique these changes were, we compared these results to data collected from the 2102Ep teratocarcinoma line and four hESC lines (H1, HS293, HS401 and SIVF-02) which displayed normal G-banding result. We identified genomic gains and losses in CH-ES1, including gains in areas containing several oncogenes. These features are similar to those observed in teratocarcinomas, and this explains the high malignancy. The CH-ES1 line was trisomic for chromosomes 1, 9, 12, 17, 19, 20 and X. Also the karyotypically (based on G-banding) normal hESC lines were also found to have several genomic changes that involved genes with known roles in cancer. The largest changes were found in the H1 line at passage number 56, when large 5 Mb duplications in chromosomes 1q32.2 and 22q12.2 were detected, but the losses and gains were seen already at passage 22. These changes found in the other lines highlight the importance of assessing the acquisition of genetic changes by hESCs before their use in regenerative medicine applications. They also point to the possibility that the acquisition of genetic changes by ESCs in culture may be used to explore certain aspects of the mechanisms regulating oncogenesis.

Effects of insulin-like growth factor binding protein 7 on apoptosis in human teratocarcinoma cells in vitro

Human teratocarcinoma cells (Tera-2) deprived of serum undergo programmed cell death which can be counteracted by simultaneous addition of IGF-II. This protective effect of IGF-II was specific in the sense that addition of IGF-binding protein 7 (IGFBP-7) resulted in an increased apoptotic rate almost comparable to that of the classical IGFBPs. Autoradiographic analysis of incorporated tritiated thymidine indicated that the proportion of S-phase cells was comparable, irrespective of total cell numbers. This further suggests that IGF-II rescues cells from apoptosis and that IGFBP-7 is a specific antagonist.

[Regulation of in vitro and in vivo differentiation of mouse embryonic stem cells, embryonic germ cells, and teratocarcinoma cells by TGFb family signaling factors]

The activity of specific signaling and transcription factors determines the cell fate in normal development and in tumor transformation. The transcriptional profiles of gene-components of different branches of TGFbeta family signaling pathways were studied in experimental models of initial stages of three-dimensional in vitro differentiation of embryonic stem cells, embryonic germ cells and teratocarcinoma cells and in teratomas and teratocarcinomas developed after their transplantation into immunodeficient Nude mice. Gene profile analysis of studied cell systems have revealed that expression patterns of ActivinA, Nodal, Lefty1, Lefty2, TGF TGFbeta1, BMP4, and GDF were identical in pluripotent stem cells whereas the mRNAs of all examined genes with the exception of Inhibin betaA/ActivinA were detected in the teratocarcinoma cells. These results indicate that differential activity of signaling pathways of the TGFbeta family factors regulates pluripotent state maintenance and pluripotent stem cell differentiation into the progenitors of three germ layers and extraembryonic structures and that normal expression pattern of TGFbeta family factors is rearranged in embryonic teratocarcinoma cells during tumor growth in vitro and in vivo.

Angiogenesis and vascular network of teratocarcinoma from embryonic stem cell transplant into seminiferous tubules

BACKGROUND

Carcinoma in situ (CIS) of the testis is considered to be a precancerous germinal cell lesion, but the precise cellular and molecular mechanisms underlying transformation of CIS into invasive pluripotent cancer cells remain to be elucidated. Moreover, a satisfactory animal model for the experimental study of germinal tumours has not been developed to date.

METHODS

We have developed a tumour model that involves the microinjection of green fluorescent protein-labelled embryonic stem (ES) cells (which are functionally equivalent to CIS cells) into syngenic mouse seminiferous tubules, a unique cell microenvironment in which germinal cells mature and CIS arise. To characterise the vascularisation of teratocarcinomas, which arise after cell transplant, we used immunohistochemistry, together with a qualitative and quantitative analysis of scanning electron microscopy images of corrosion casting samples.

RESULTS

Embryonic stem cells transplanted into seminiferous tubules did not differentiate into germinal cells, but rather they behaved as invasive embryonal carcinoma (EC) stem cells. The vascular pattern of the experimental teratocarcinomas showed a highly disorganised architecture, and some of the neoplastic capillaries were derived, at least in part, from the original transplanted ES cells.

CONCLUSION

The transplantation of pluripotent ES cells into seminiferous tubules efficiently recapitulates the early stages of development of teratocarcinomas. Consequently, this method constitutes a novel in vivo model to study the mechanisms of invasion and progression of experimental germinal tumours.

ZNF423 is critically required for retinoic acid-induced differentiation and is a marker of neuroblastoma outcome

Retinoids play key roles in differentiation, growth arrest, and apoptosis and are increasingly being used in the clinic for the treatment of a variety of cancers, including neuroblastoma. Here, using a large-scale RNA interference-based genetic screen, we identify ZNF423 (also known as Ebfaz, OAZ, or Zfp423) as a component critically required for retinoic acid (RA)-induced differentiation. ZNF423 associates with the RARalpha/RXRalpha nuclear receptor complex and is essential for transactivation in response to retinoids. Downregulation of ZNF423 expression by RNA interference in neuroblastoma cells results in a growth advantage and resistance to RA-induced differentiation, whereas overexpression of ZNF423 leads to growth inhibition and enhanced differentiation. Finally, we show that low ZNF423 expression is associated with poor disease outcome in neuroblastoma patients.

MicroRNA expression profiling during neural differentiation of mouse embryonic carcinoma P19 cells

MicroRNAs (or miRNAs) are small non-coding RNAs (21-25 nucleotides) that are involved in a wide range of activities related to the development and differentiation of cells. Comparison of the miRNA expression profiles of mouse P19 embryonic carcinoma cells with those of differentiated neural stem cells showed that the expression level of 65 miRNAs changed (2-fold) after differentiation. MiR-124a was dramatically upregulated (more than 20-fold) while miRNAs of the miR-302 family and those in the miR-290-295 cluster were strongly down-regulated. Further analysis revealed that some important factors such as Oct4 and Sox2 appeared to be involved in the regulation of these miRNAs. These results may contribute to a better understanding of miRNA-regulated neural differentiation in early mouse embryos.

[Growth and differentiation of cell hybrids obtained by fusing mouse PCC4azal teratocarcinoma cells and mouse spleen cells under different in vitro culture conditions]

Cell hybrids obtained by fusing mouse PCC4azal teratocarcinoma cells and spleen cells induced to proliferation and treated with the demethylating agent 5-azacytidine prior to fusion are described. The obtained hybrids demonstrated no expression of T lymphocyte marker genes CD11 and CD45, which indicates possible somatic nucleus reprogramming by factors present in teratocarcinoma cells. Irrespective of culture conditions, cell hybrids demonstrated a relatively stable chromosome number: they lost on average no more than four chromosomes after 30 passages. Culturing in medium containing hypoxanthine, aminopterin, and thymidine (selective conditions) decreased the differentiation capacity of cell hybrids compared to nonselective conditions, which is likely due to the inhibition of their metabolism. For the first time, teratocarcinoma cell hybrid differentiation into cardiomyocytes under the influence of DMSO has been demonstrated in vitro.

Impact of hyperglycemia on early embryo development and embryopathy: in vitro experiments using a mouse model

BACKGROUND

The aim of this study is to model the processes of early embryopathy seen in human pregnancy complicated by maternal hyperglycemia secondary to maternal diabetes using a mouse embryo culture system.

METHODS

Female mice were superovulated and mated in pairs. Two-cell embryos were harvested from the oviducts and cultured in vitro in KSOM medium (synthetic oviductal medium enriched with potassium) supplemented with 0.2, 5.56, 15.56 or 25.56 mM d-glucose. Cell proliferation, differentiation and apoptosis were assessed. Experiments were performed in constant, embryos exposed to a particular concentration of glucose (0.2, 5.56, 15.56 or 25.56 mM) from harvest to either Day 5 post fertilization (pf) or Day 8 pf, and fluctuating, embryos exposed to alternate high 25.56 mM and normal 5.56 mM concentrations of glucose between harvest and Day 5 pf, glycemic culture.

RESULTS

Expected levels of blastocyst formation and hatching were seen at 0.2 and 5.56 mM concentrations of glucose but both were impaired at higher concentrations (chi(2), P < 0.005; P < 0.001). Total cell numbers (P < 0.002) and cell allocation to the inner cell mass (P < 0.01) were reduced, but with no evidence of enhanced apoptosis in the hyperglycemic cultures. Variation in hyperglycemic exposure of the embryos on Days 2, 3 and 4 showed no adverse effects of hyperglycemia up to 24 h, but 48 and 72 h exposures were equally embryopathic (P < 0.01).

CONCLUSIONS

Hyperglycemic exposure for >24 h is toxic to early embryo development. These findings may explain the lower than expected implantation rates and higher than expected rates of congenital abnormality and early pregnancy loss seen in patients with diabetes, particularly those with poor diabetic control.

Efficiency of two different transfection reagents for use with human NTERA2 cells

The teratocarcinoma cell line NTERA2 is recently used in a wide range of researches (from developmental biology to toxicology, for their ability to be induced to neural differentiation. In order to study the genetic potential of these cells, it is needed to use methods for gene silencing and/or mRNA interference, allowing cell viability and further differentiation. To check these features, we simultaneously tested the transfection efficiency of NTERA2, A549 and HeLa cells with Metafectene PRO (Biontex, Germany) and another optimal transfection reagent currently used in our Laboratory, using as a reporter gene the DsRed2 vector (Clontech, Mountain View, CA). Under our culture conditions for NTERA2 and HeLa cells, Metafectene PRO transfection method was found to possess high throughput performance, that allows low concentration rate and low exposure time to excitation light source, thus reducing both toxicity and phototoxicity.

Embryonic germ cell lines and their derivation from mouse primordial germ cells

When primordial germ cells of the mouse are cultured on feeder layers with the addition of the polypeptide signalling molecules leukaemia inhibitory factor, Steel factor and basic fibroblast growth factor they give rise to cells that resemble undifferentiated blastocyst-derived embryonic stem cells. These primordial germ cell-derived embryonic germ cells (EG cells) can be induced to differentiate extensively in culture and also form teratocarcinomas when injected into nude mice. Additionally, they contribute to chimeras when injected into host blastocysts. We have derived multiple EG cell lines from 8.5 days post coitum (dpc) embryos of C57BL/6 inbred mice. Four independent EG cell lines with normal male karyotypes have formed chimeras (up to 70% coat colour chimerism) when injected into BALB/c host blastocysts. Chimeric mice from all four cell lines are fertile, but only those from one line have transmitted coat colour markers through the germline. Studies have also been carried out to determine whether gonadal primordial germ cells can give rise to pluripotent EG cells. Germ cells from gonads of 15.5 dpc C57BL/6 embryos and newborn mice failed to produce EG cell lines. EG cell lines capable of forming teratocarcinomas and coat colour chimeras have been established from primordial germ cells of 12.5 dpc genital ridges. We are currently testing the genomic imprinting status of the insulin-like growth factor type 2 receptor gene (Igf2r) in our different EG cell lines.

[Seminoma and teratocarcinoma: synchronic unitesticular presentation as independent nodules with different histologies? Ultrasound characteristics]

OBJECTIVE

To describe the ultrasound characteristics, vascularization pattern (colour Doppler ultrasound) and possible histogenesis of one case of synchronic untesticular seminoma and teratocarcinoma as independent tumor nodules, histologically different, in a 19-year-old patient with testicular mass for eight months.

METHODS

Conventional ultrasound, colour Doppler ultrasound, and high resolution Doppler angiogram were performed, analyzing vascular flows. After resection of the tumor, macroscopic and histological sections were related with ultrasound images.

RESULTS

The patient showed three independent, well limited, tumoral nodules in the right testicle: two of them heterogeneous, 20 and 33 mm in diameter, with cystic areas and calcifications. The third nodule was solid, hypoechoic and homogeneous, 26 mm in diameter. All nodules presented an increase in vascularization with low resistance arterial flows. Histologically the first two nodules were teratocarcinomas (predominantly mature teratoma and embryonal carcinoma) and the third classic seminoma.

CONCLUSIONS

Although seminoma and mixed germ cell tumors are common, "their presentation in the some testicle as independent nodules with different histologies is a rarely referred case in the literature, which allows us to apply a histogenetic and ultrasound-pathologic correlation model in seminomatous and nonseminomatous tumors. The presence of cystic cavities and gross calcifications is highly correlated with teratoma. In our case there are not significant differences in the vascularization pattern with Doppler ultrasound.

Marked change in microRNA expression during neuronal differentiation of human teratocarcinoma NTera2D1 and mouse embryonal carcinoma P19 cells

MicroRNAs (miRNAs) are small noncoding RNAs, with a length of 19-23 nucleotides, which appear to be involved in the regulation of gene expression by inhibiting the translation of messenger RNAs carrying partially or nearly complementary sequences to the miRNAs in their 3' untranslated regions. Expression analysis of miRNAs is necessary to understand their complex role in the regulation of gene expression during the development, differentiation and proliferation of cells. Here we report on the expression profile analysis of miRNAs in human teratocarcinoma NTere2D1, mouse embryonic carcinoma P19, mouse neuroblastoma Neuro2a and rat pheochromocytoma PC12D cells, which can be induced into differentiated cells with long neuritic processes, i.e., after cell differentiation, such that the resultant cells look similar to neuronal cells. The data presented here indicate marked changes in the expression of miRNAs, as well as genes related to neuronal development, occurred in the differentiation of NTera2D1 and P19 cells. Significant changes in miRNA expression were not observed in Neuro2a and PC12D cells, although they showed apparent morphologic change between undifferentiated and differentiated cells. Of the miRNAs investigated, the expression of miRNAs belonging to the miR-302 cluster, which is known to be specifically expressed in embryonic stem cells, and of miR-124a specific to the brain, appeared to be markedly changed. The miR-302 cluster was potently expressed in undifferentiated NTera2D1 and P19 cells, but hardly in differentiated cells, such that miR-124a showed an opposite expression pattern to the miR-302 cluster. Based on these observations, it is suggested that the miR-302 cluster and miR-124a may be useful molecular indicators in the assessment of degree of undifferentiation and/or differentiation in the course of neuronal differentiation.

[Sinonasal teratocarcinosarcoma: a clinical, radiologic and pathologic study of 5 cases]

OBJECTIVE

To study the clinical, radiologic and pathologic features, as well as differential diagnosis of teratocarcinosarcoma in nasal cavity and paranasal sinuses.

METHODS

Light microscopic examination and immunohistochemical study was performed in 5 cases of sinonasal teratocarcinosarcoma. The clinical, radiologic and pathologic features were analyzed and the literature was reviewed.

RESULTS

All 5 patients were males and their age ranged from 34 to 43 years (mean age = 39 years). The clinical presentation was nasal obstruction, epistaxis and headache. Physical examination often revealed a polypoid mass with contact bleeding. Computed tomography showed a homogeneous nasal mass with obturation of sinuses. Cystic changes, calcification or ossification was not observed. Histologically, the tumor showed a heterogeneous admixture of components from the 3 germ cell layers, exhibiting various degrees of maturation. Squamous epithelium, smooth muscle cells, chondro-osseous tissue, intestinal or respiratory type epithelium, "fetal-type" clear cells and immature neuroepithelium were commonly seen. Immunohistochemical study demonstrated that the epithelial component expressed cytokeratin and epithelial membrane antigen, while the mesenchymal component variably expressed vimentin, smooth muscle actin and S-100 protein. On the other hand, the neuroepithelial component expressed neuron-specific enolase, synaptophysin and chromogranin, and the primitive component expressed CD99. The initial biopsy diagnosis included capillary hemangioma, olfactory neuroblastoma, craniopharyngioma and malignant mixed tumor. Follow-up information was available in all patients. Two of which had local recurrence and 1 had cervical lymph node metastasis.

CONCLUSIONS

Sinonasal teratocarcinosarcoma is a rare and highly malignant tumor occurring in sinonasal tract. It manifests mainly in adult males and is characterized by a complex admixture of teratomatous and carcinosarcomatous components. "Fetal-type" clear cells, squamous epithelium and immature neuroepithelium represent important histologic characteristics useful in diagnosis.

The soluble wnt receptor Frizzled8CRD-hFc inhibits the growth of teratocarcinomas in vivo

Wnt signaling is important for normal cell proliferation and differentiation, and mutations in pathway components are associated with human cancers. Recent studies suggest that altered wnt ligand/receptor interactions might also contribute to human tumorigenesis. Therefore, agents that antagonize wnt signaling at the extracellular level would be attractive therapeutics for these cancers. We have generated a soluble wnt receptor comprising the Frizzled8 cysteine-rich domain (CRD) fused to the human Fc domain (F8CRDhFc) that exhibits favorable pharmacologic properties in vivo. Potent antitumor efficacy was shown using the mouse mammary tumor virus-Wnt1 tumor model under dosing conditions that did not produce detectable toxicity in regenerating tissue compartments. In vitro, F8CRDhFc inhibited autocrine wnt signaling in the teratoma cell lines PA-1, NTera-2, Tera-2, and NCCIT. In vivo, systemic administration of F8CRDhFc significantly retarded the growth of tumor xenografts derived from two of these cell lines, PA-1 and NTera-2. Pharmacodynamic markers of wnt signaling, identified by gene expression analysis of cultured teratoma cells, were also modulated in the tumor xenografts following treatment with F8CRDhFc. Additionally, these markers could be used as indicators of treatment efficacy and might also be useful in identifying patients that would benefit from the therapeutic agent. This is the first report showing the efficacy of a soluble wnt receptor as an antitumor agent and suggests that further development of wnt antagonists will have utility in treating human cancer.

Nasal teratocarcinosarcoma - a case report

A 79-year-old man noticed nasal obstruction and bleeding caused by a pedunculated tumor in the left nasal cavity. The tumor revealed a malignant neoplasm predominantly composed of immature neuroepithelial cells with rosettes and palisading patterns, rhabdomyoblastic cells with positivity for desmin and cross-striations, and immature mucin-producing glandular cells. Small amounts of mature chondroid tissue and neurofibrillary matrix were also present. Therefore, the tumor was diagnosed as nasal teratocarcinosarcoma.

ER stress induces the expression of Jpk, which inhibits cell cycle progression in F9 teratocarcinoma cell

Jopock (Jpk), a transacting factor associated with the position-specific regulatory element of murine Hoxa-7, has shown to induce cell death in both prokaryotic and eukaryotic cells when introduced and overexpressed. Since Jpk protein harbors a transmembrane domain (TM) and a putative endoplasmic reticulum (ER) -retention signal at the N terminus, a subcellular localization of the protein was analyzed after fusing it into the green fluorescent protein (GFP). Both N-term- (Jpk-EGFP) and C-term-fused Jpk (EGFP-Jpk) showed to be localized in the ER when analyzed under the fluorescence microscope after staining the cells with ER- and Mito-Tracker. Through deletion analysis TM turned out to be important for ER localization of Jpk. When flow cytometric analysis was performed, both cells expressing Jpk-EGFP and EGFP-Jpk led cell cycle arrest and subsequent apoptotic cell death. In order to see whether Jpk is expressed during ER stress-mediated apoptosis, F9 cells were treated with DTT, an ER stress inducer. In the presence of 4 mM of DTT, about 50% of cells died strongly expressing Jpk (sevenfold) as well as Grp78, a molecular chaperone, and CHOP-10, a well-known apoptotic protein. When cells were transfected with both pEGFP-Jpk and pJpk-EGFP, cell cycle progression was interrupted compared to those of control cells. In summary, excess ER stress upregulated the expression of Jpk, which seemed to inhibit the cell cycle progression. These results altogether suggest that Jpk could be a useful cell death-triggering molecule applicable for cancer therapy as well as a useful target molecule for the treatment of certain neurodegenerative diseases caused by ER stress.

Culture adaptation of embryonic stem cells echoes germ cell malignancy

Teratocarcinomas are a subset of tumours that result from the neoplastic transformation of primordial germ cells. Such germ cell tumours (GCT) are histologically heterogeneous, reflecting a capacity for differentiation (pluripotency) of their embryonal carcinoma (EC) stem cells. However, malignant evolution of these tumours may ultimately correlate with a decrease in pluripotency, because this would tend to increase the propensity of EC cells for self-renewal. Human embryonic stem (ES) cells, derived from early blastocysts, closely resemble EC cells and, on prolonged culture in vitro, acquire progressive genetic changes that show striking similarity to those seen in GCT (e.g. gain of material from chromosome 12). In parallel, these abnormal ES cells show enhanced population growth rates and plating efficiencies, indicative of their adaptation to culture conditions. Understanding the mechanisms that drive such culture adaptation of ES cells may also provide insights into the development and progression of GCT.

Global mRNA analysis to determine a transcriptome profile of cancer stemness in a mouse model

BACKGROUND

Striking similarities between stem cells and cancer cells have led to the concept of the existence of a cancer stem cell, a concept that has since been documented in many tumours including breast, brain and prostate tumours. Teratocarcinomas are malignant tumours occurring predominantly in the testes composed of undifferentiated stem cells and mature tissues. Cancer stemness was studied using the teratocarcinoma model of tumourigenesis.

MATERIALS AND METHODS

The gene expression profile of murine embryonic stem cell lines was compared to its malignant counterpart, murine teratocarcinoma cell lines. Validation was performed using real-time quantitative PCR.

RESULTS

A list of 1170 differentially expressed genes was obtained. Significant pathways involved in cancer stemness included oxidative stress and angiogenesis. Transcription factors and extracellular matrix molecules appeared prominently.

CONCLUSION

Novel molecules have been highlighted including decorin, an extracellular matrix protein, which may provide opportunities for the investigation of innovative strategies in the future treatment of cancer.

Jpk, a novel cell death inducer, regulates the expression of Hoxa7 in F9 teratocarcinoma cells, but not during apoptosis

Hox proteins play critical role in animal pattern formation during embryogenesis. During the study on the regulation of Hox gene expression, a novel gene, Jpk, has been isolated as a putative regulatory factor associating with the upstream regulatory sequence of murine Hoxa7. Since overexpression of Jpk caused cell death in bacteria as well as in eukaryotic cells and Hox has been reported to participate in apoptosis, we tried to analyze the relationship between Jpk and Hoxa7 during apoptosis after confirming the regulatory effect of Jpk on the expression of Hoxa7 in F9 teratocarcinoma cells. For that purpose, an effector (pEGFP-Jpk) and reporter (pGL2-NM307) plasmid containing a luciferase gene under the 307 bp (NM307) of Hoxa7 upstream regulatory sequence was constructed. In the presence of Jpk (effector), luciferase activity was increased and this enhancement was decreased by siRNA against Jpk, suggesting that Jpk is a regulatory factor of Hoxa7. In order to see whether Jpk still regulates the expression of Hoxa7 during apoptosis, F9 cells were transiently transfected with pcDNA-Jpk, and the expression of Jpk, Hoxa7, and CHOP-10 was analyzed using RT-PCR. Hoxa7 and CHOP-10 were not upregulated in the presence of Jpk although Jpk seemed to cause apoptosis, indicating that the regulatory mechanism of Jpk on the expression of Hoxa7 might be different depending on the cell status, that is, an apoptotic or proliferative condition.

[Comparative analysis of expression of TGFbeta family factors and their receptors in mouse embryonic stem and embryonic teratocarcinoma cells]

Specific factors that determine the cell fate in early embryogenesis are modulated during interaction of signaling pathways to form a unique regulatory network inside the cell, which is essential for differentiation of various cell populations. We carried out a comparative study of expression of the genes of TGFbeta growth factors and their receptors at the initial stages of differentiation of the embryonic stem cells, during formation of spheroids of the embryonic teratocarcinoma cells, and during growth of neoplastic cells in vivo in immunodeficient mice. The patterns of expression of the genes Activin, Nodal, Lefty1, Lefty2, BMP, and TGF1 and their receptors ActRI, ActRII, BMPRI, TGFbeta1R1, and Tdgf proved to be identical. Expression of alpha-fetoprotein and transcription factor Gata4 protein, specific for the primary endoderm, was detected in the embryonic teratocarcinoma cells. In Undifferentiated embryonic stem cells, expression of Gata4 was found at the mRNA level, while expression at the level of proteins appeared only in the primary endoderm cells in the embryoid bodies. The results obtained suggest that despite the existence of similar signaling systems in the embryonic stem and teratocarcinoma cells, the presence of different intracellular specific factors forms radically different regulatory pathways, which determine the program of their differentiation.

Sentinel Lymph Node Imaging Using Quantum Dots in Mouse Tumor Models

We demonstrate that quantum dots injected into two model tumors rapidly migrate to sentinel lymph nodes. PEG-coated quantum dots having terminal carboxyl, amino, or methoxyl groups all migrated from the tumor to surrounding lymph nodes similarly. Passage from the tumor through lymphatics to adjacent nodes could be visualized dynamically through the skin; at least two nodes could usually be defined. Imaging during necropsy confirmed confinement of the quantum dots to the lymphatic system and demonstrated easy tagging of sentinel lymph nodes for pathology. Examination of the sentinel nodes identified by quantum dot localization showed that at least some contained metastatic tumor foci.

Cervical mature teratoma 17 years after initial treatment of testicular teratocarcinoma: report of a late relapse

BACKGROUND

Late relapses of testicular germ cell tumor are uncommon. We report a case of cervical mature teratoma appeared 17 years after treatment of testicular teratocarcinoma.

CASE PRESENTATION

A 20-year-old patient underwent left sided orchiectomy followed by systemic therapy and retroperitoneal residual mass resection in 1989. He remained in complete remission for 200 months. In 2005 a huge left supraclavicular neck mass with extension to anterior mediastinum appeared. Radical surgical resection of the mass was performed and pathologic examination revealed mature teratoma.

CONCLUSION

This is one of the longest long-term reported intervals of a mature teratoma after treatment of a testicular nonseminoma germ cell tumor. This case emphasizes the necessity for follow up of testicular cancer throughout the patient's life.

Simulation of stroke-related damage in cultured human nerve cells

We describe a novel cell culture protocol for the generation of neurons from a human teratocarcinoma cell line. These neurons were used to investigate hypoxic-ischaemic cell damage and for developing neuroprotective strategies. Cultures of human model neurons should eventually serve to reduce the number of experimental animals in cerebral stroke research.

[Tumoral degeneration occurring over a non-healing meningocele. Report of two cases]

A giant meningocelic sac has not been usually described in adult patients, due to the fact that it shows a low incidence and few newborn have survived to date though the malformation is benign. We report two cases of patients born with the described malformation and who were not operated at that time, so they reached adulthood with bigger sacs. They needed surgery to remove the sacs, for a different reason. The older one had a fistulous abcess but the LCR did not come out, and it did not improved by the application of topic and antibiotic treatment. The other patient showed a progressive growth of the malformation during the last year, skin hardening and pain. The histological study of the dried sacs proved the existence of a carcinomatous degeneration. In the patients we have treated, it seems that a chronic irritation of the LCR and the appearance of multipotent cells in the meningocele may favour the malignancy of the tissues surrounding the sac. This possible malignancy, already described in the bibliography, suggests a prompt elective surgical treatment of the patients with these congenital lesions as soon as possible.

Salivary gland malignancy with divergent differentiation: is it a teratocarcinosarcoma?

Four poorly differentiated malignant lesions occurred in a 60-year-old Chinese male in the nasal cavity, submandibular gland, a lymph node in the neck, and the mandible. These malignant lesions developed within an 8-year period and each showed distinctive histological features. Among these malignant lesions, the neoplasm in the submandibular gland presented variegated histological and immunohistochemical (IHC) features and posed a diagnostic challenge in interpretation. Based on microscopic and IHC findings, we believe the diagnosis of teratocarcinosarcoma is justified for the submandibular neoplasm and the metastasis in the lymph node. The pathological features and diagnoses of these malignant lesions are discussed.

Antitumor activity of the retinoid-related molecules (E)-3-(4'-hydroxy-3'-adamantylbiphenyl-4-yl)acrylic acid (ST1926) and 6-[3-(1-adamantyl)-4-hydroxyphenyl]-2-naphthalene carboxylic acid (CD437) in F9 teratocarcinoma: Role of retinoic acid receptor gamma and retinoid-independent pathways

The retinoid-related molecules (RRMs) ST1926 [(E)-3-(4'-hydroxy-3'-adamantylbiphenyl-4-yl)acrylic acid] and CD437 (6-[3-(1-adamantyl)-4-hydroxyphenyl]-2-naphthalene carboxylic acid) are promising anticancer agents. We compared the retinoic acid receptor (RAR) trans-activating properties of the two RRMs and all-trans-retinoic acid (ATRA). ST1926 and CD437 are better RARgamma agonists than ATRA. We used three teratocarcinoma cell lines to evaluate the significance of RARgamma in the activity of RRMs: F9-wild type (WT); F9gamma-/-, lacking the RARgamma gene; F9gamma51, aF9gamma-/-derivative, complemented for the RARgamma deficit. Similar to ATRA, ST1926 and CD437 activate cytodifferentiation only in F9-WT cells. Unlike ATRA, ST1926 and CD437 arrest cells in the G2/M phase of the cell cycle and induce apoptosis in all F9 cell lines. Our data indicate that RARgamma and the classic retinoid pathway are not relevant for the antiproliferative and apoptotic activities of RRMs in vitro. Increases in cytosolic calcium are fundamental for apoptosis, in that intracellular calcium chelators abrogate the process. Comparison of the gene expression profiles associated with ST1926 and ATRA in F9-WT and F9gamma-/-indicates that the RRM activates a conspicuous nonretinoid response in addition to the classic and RAR-dependent pathway. The pattern of genes regulated by ST1926 selectively, in a RARgamma-independent manner, provides novel insights into the possible molecular determinants underlying the activity of RRMs in vitro. Furthermore, it suggests that RARgamma-dependent responses are relevant to the activity of RRMs in vivo. Indeed, the receptor hinders the antitumor activity in vivo, in that both syngeneic and immunosuppressed SCID mice bearing F9gamma-/- tumors have increased life spans after treatment with ST1926 and CD437 relative to their F9-WT counterparts.

Roles for Rho/ROCK and vinculin in parietal endoderm migration

The first cell migration event in the mouse embryo is the movement of parietal endoderm cells from the surface of the inner cell mass facing the blastocoel cavity to line the inner surface of the trophectoderm. F9 embryoid bodies provide an in vitro model for this event. They have an inner core of undifferentiated stem cells surrounded by an outer visceral endoderm layer. When plated on a laminin coated substrate, visceral endoderm transitions to parietal endoderm and migrates onto the dish, away from the attached embryoid body. We now show that this outgrowth contains abundant focal complexes and focal adhesions, as well as lamellipodia and filopodia. Treatment with the ROCK inhibitor Y-27632 promotes a 2-fold increase in outgrowth, and a transition from focal adhesions and associated stress fibers, to focal complexes and a decrease in stress fibers. ROCK inhibition also leads to an increase in lamellipodia. Inhibition of RhoA by transfection of a vector encoding C3 transferase, direct administration of the C3 enzyme, or transfection of a vector encoding p190 Rho GTPase Activating Protein also promotes outgrowth and an apparent transition from focal adhesions to focal complexes. Parietal endoderm outgrowth generated using vinculin-deficient F9 stem cells migrates 2-fold further than wild type cultures, but this outgrowth retains the morphology of wild type parietal endoderm, including focal adhesions and stress fibers. Addition of Y-27632 to vinculin-null outgrowth cultures further stimulates migration an additional 2-fold, supporting the conclusion that Rho/ROCK and vinculin regulate parietal endoderm outgrowth by distinct pathways.

Knocking out the regulatory beta subunit of protein kinase CK2 in mice: gene dosage effects in ES cells and embryos

Knocking out the regulatory beta subunit of protein kinase CK2 in mice leads to early embryonic lethality. Heterozygous CK2beta (CK2beta+/-) knockout mice do not show an obvious phenotype. However, the number of heterozygous offsprings from CK2B+/- inter-crossings is lower than expected, meaning that some heterozygous embryos do not survive. Interestingly, CK2beta+/- ES (Embryonic Stem) cells express a considerably lower level of CK2beta than wild-type ES cells, whereas the level of CK2beta in organs from heterozygous adult mice does not significantly differ from those of wild-type mice. The data suggest a compensatory mechanism that adjusts CK2beta levels during development in the majority of, but not in all, cases (Mol Cell Biol 23: 908-915, 2003). In order to find an explanation for the gene dosage effect observed for heterozygous offsprings, we analysed embryos at mid-gestation (E10.5) as well as wild-type and CK2beta+/- ES cells for differences in growth rate and response to different stress agents. Analysis of E10.5 embryos generated from heterozygous matings revealed about 20% of smaller retarded CK2beta+/- embryos. No correlation between CK2beta levels in normal looking and retarded CK2beta+/- embryos were found. However, a different post-translational form of CK2beta protein has been detected in these retarded embryos. Cellular parameters such as growth rate and G1-, G2-checkpoints in ES cells were identical in both wild-type and CK2beta+/- cells. When ES cells were injected to induce differentiated teratocarcinoma in syngenic mice, the size of the tumours correlated with the level of CK2beta.

Gene therapy, cell transplantation and stroke

The use of neuroteratocarcinoma cells for transplantation therapy in stroke has emerged as a strategy for cell replacement therapy that has begun its transition from basic science laboratories to a clinical setting. Procurement logistics and novel neuroprotective functions associated with these cells allow neuroteratocarcinoma cells to serve as efficacious alternatives to using fetal cells as donor cell grafts for stroke therapy, although the optimal transplantation regimen must still be determined. In particular, the limitations of current stroke treatments and management reveal an urgent need to examine the efficacy of experimental treatments, such as neural transplantation, in order to develop better treatment therapies. This chapter will discuss the characteristics of NT2N cells, the role of the host brain microenvironment and NT2N cell grafts, laboratory research and clinical trials for the intracerebral transplantation of NT2N cells in stroke, the mechanisms underlying the grafts' effects, and NT2N cell grafts and the need for immunosuppression. This chapter will also highlight some of the most recent findings regarding NT2N cells.

Rationale for individualized therapy in Sinonasal Teratocarcinosarcoma (SNTC): case report

BACKGROUND

Sinonasal Teratocarcinosarcoma (SNTC) is a very unusual and aggressive neoplasm characterized by the combination of malignant teratoma and carcinosarcoma features. We present the first case of malignant SNTC treated with individualized multimodal therapy including a histology-specific chemotherapy.

CASE REPORT

A 31-year-old man presented with an obstruction of the right pansinus. Histology showed an SNTC with major parts of small cell, poorly differentiated carcinoma and a small proportion of highly differentiated embryonal rhabdomyosarcoma. An operation was performed followed by intraoperative application of a 5-FU ointment. Adjuvant chemotherapy with cisplatin, etoposid and ifosfamid were given in regard to the major components of this heterogeneous tumor. Radiotherapy up to 59.4 Gy was applied.

CONCLUSION

36 months after the end of therapy, there is no sign of tumor recurrence or metastasis in our patient. We suggest that surgery, radiotherapy and a histology-specific multidrug chemotherapy seems to be a therapeutic approach that is appropriate for this heterogeneous tumor.