EACR-MRS conference on Seed and Soil: In Vivo Models of Metastasis.

New experimental tools are urgently required to better understand the metastatic process. The importance of such tools is underscored by the fact that many anti-cancer therapies are generally ineffective against established metastases. This makes a major contribution to the fact that metastatic spread is responsible for over 90% of cancer patient deaths. It was therefore timely that the recent "Seed and Soil: In Vivo Models of Metastasis" conference held in Berlin, Germany (27-29 of November 2017) aimed to give an in-depth overview of the latest research models and tools for studying metastasis, and to showcase recent findings from world-leading metastasis researchers. This Meeting Report summarises the major themes of this ground-breaking conference.

Breast cancer, side population cells and ABCG2 expression.

Recurrent metastatic breast cancer may arise in part due to the presence of drug resistant adult stem cells such as Side Population (SP) cells, whose phenotype has been demonstrated to be due to the expression of ABCG2. We hypothesised that SP may be identified in Fine Needle Aspirates (FNAs) and their presence may be determined by expression of ABCG2 in breast tumours. SP and non-side population cells (NSP) were isolated using dual wavelength flow cytometry combined with Hoechst 33342 dye efflux and analysed for expression of ABCG2 and chemoresistance. FNA samples used in SP analysis were matched with paraffin-embedded tissue which was used in immunohistochemical analysis to assess ABCG2 expression. Results were correlated to the pathobiology of the tumour. MCF7 and MDA-MB-231 cell lines contain SP cells. MCF7 SP have increased expression of ABCG2 and increased resistance to mitoxantrone compared to NSP cells. The presence of SP in FNAs were significantly associated with ER-negative (p=0.008) and with triple negative breast cancers (p=0.011) which were also found to have a significant increase in ABCG2 protein expression. ABCG2 transcript was detected in some but not all SP cell populations isolated from FNA samples.

Incidence and survival of childhood bone cancer in northern England and the West Midlands, 1981-2002.

There is a paucity of population-based studies examining incidence and survival trends in childhood bone tumours. We used high quality data from four population-based registries in England. Incidence patterns and trends were described using Poisson regression. Survival trends were analysed using Cox regression. There were 374 cases of childhood (ages 0-14 years) bone tumours (206 osteosarcomas, 144 Ewing sarcomas, 16 chondrosarcomas, 8 other bone tumours) registered in the period 1981-2002. Overall incidence (per million person years) rates were 2.63 (95% confidence interval (CI) 2.27-2.99) for osteosarcoma, 1.90 (1.58-2.21) for Ewing sarcoma and 0.21 (0.11-0.31) for chondrosarcoma. Incidence of Ewing sarcoma declined at an average rate of 3.1% (95% CI 0.6-5.6) per annum (P=0.04), which may be due to tumour reclassification, but there was no change in osteosarcoma incidence. Survival showed marked improvement over the 20 years (1981-2000) for Ewing sarcoma (hazard ratio (HR) per annum=0.95 95% CI 0.91-0.99; P=0.02). However, no improvement was seen for osteosarcoma patients (HR per annum=1.02 95% CI 0.98-1.05; P=0.35) over this time period. Reasons for failure to improve survival including potential delays in diagnosis, accrual to trials, adherence to therapy and lack of improvement in treatment strategies all need to be considered.

Stability of singly hydrated silanone on silicon quantum dot surfaces: density functional simulations.

A key to understanding the optical characteristics of silicon quantum dots is the role of surface bonded species that introduce states to the band-gap. In particular, oxygen bonded in a silanone configuration is thought to be a source of shifts in emission during oxidation. We report the results of density-functional calculations examining the properties of such surface structures. We find single hydration of a simple, neutral silanone molecule leads to a barrierless conversion into a di-hydroxyl structure, and that similar processes are weakly activated on larger systems. However, we show that charging has a significant impact upon stability, with the attachment of an electron greatly increasing the barrier for converting silanone to di-hydroxyl termination. The relatively stable, negatively-charged silanone structures are predicted to lead to large red-shifts in the onset of optical absorption.

Theory of Jahn-Teller distortions of the P donor in diamond.

Phosphorus, the current standard n-type dopant in diamond, has been correlated with isotropic, trigonal and tetragonal paramagnetic centres, suggesting that it may undergo a symmetry lowering distortion, perhaps of a Jahn-Teller type. We present first-principles calculations for examining the energetics of various sub-group symmetries of the on-site, tetrahedral donor, and show that C2v, C3v and D2d conformations reduce the total energy and conform to the Jahn-Teller theorem. We also present a qualitative explanation of the resulting quantum-mechanical states. The small amount of energy saved by the distortion may indicate a dynamic Jahn-Teller effect.

Multiple drug resistance mutations in human immunodeficiency virus in semen but not blood of a man on antiretroviral therapy.

The concept that the male reproductive tract harbors isolated reservoirs of human immunodeficiency virus (HIV) infection has now been widely accepted. The significance of semen viral burden to sexual transmission of HIV is obvious; however, its contribution to disease progression is unknown. We report a case study that demonstrates the emergence of resistance-conferring mutations to antiviral therapy in infected seminal leukocytes from a man with asymptomatic prostatitis associated with leukospermia. This finding demonstrates the potential importance of male reproductive tract organs to the development of therapy resistance in HIV-infected men.

Prostate specific antigen is detectable in formalin-fixed semen.

OBJECTIVE: To conduct a pilot study to test whether or not prostate specific antigen (PSA) and/or PSA-positive cells can be detected and characterized in semen specimens archived in aldehyde fixative. MATERIALS AND METHODS: Specimens from 12 men were examined, six before elective vasectomy and six undergoing infertility evaluation. Fixed semen elements were assessed immunocytologically using monoclonal antibodies against PSA and leucocyte common antigen, CD 45, as a control. RESULTS: PSA was detectable in the semen from the fertile men as amorphous protein and contained within round vesicles (prostasomes). Semen from men undergoing infertility evaluation contained a greater variation in detectable forms and amount of PSA than the specimens from the fertile men, including PSA associated with some nonspermatozoal cells (NSCs). CONCLUSION: PSA is detectable by immunocytological analysis of semen specimens archived in aldehyde-based fixative. Three forms of PSA were detected; within round vesicles characteristic of prostasomes, associated with some NSCs, and as amorphous protein. The detected variations suggest that analysis of PSA-positive semen elements may provide important insights into prostate physiology.

Human immunodeficiency virus in semen arises from a genetically distinct virus reservoir.

The reservoir of human immunodeficiency virus (HIV) in semen is unknown. Several lines of evidence suggest that semen HIV may not arise from the same reservoir of infection as peripheral blood. If true, the viral burden in the two compartments could be qualitatively and quantitatively different, a scenario of potentially profound significance for the design of effective strategies of treatment, disease monitoring, and infection containment. We report here that the ratio of infected to uninfected leukocytes in ejaculated semen specimens is highly discordant with paired blood samples, demonstrating that they derive from distinct populations of infected cells. In addition, infectious HIV was isolated from semen cells, but not from blood cells, of an individual on triple antiretroviral therapy; the absence of major resistance-conferring mutations in the semen virus indicates that it was replicating in isolation from the antiviral agents. The compartmentalization of blood and semen infection was further supported by genetic analysis of several infectious HIV clones isolated from semen cells and peripheral blood cells of another donor not on antiretroviral therapy. Protease gene sequence analyses revealed significant divergence of the two viral populations. These findings confirm the distinct compartmentalization of HIV in the semen of this study cohort, and support the concept that semen HIV arises from an isolated reservoir of infection that may function independently in the pathobiology of HIV disease.

Acid-labile adducts to protein can be used as indicators of the cysteine S-conjugate pathway of trichloroethene metabolism.

Covalent binding of radiolabel to tissue proteins following [14C]trichloroethene (TRI) exposure has been used as a measure of TRI activation. Gross binding of 14C label does not differentiate between alternate routes of metabolism and can be confounded when there is significant metabolic incorporation of radiolabel. We examined the covalent association of 14C label to hepatic and renal proteins in male F344 rats and B6C3F1 mice following oral treatment with [14C]TRI and three metabolites of TRI: [14C]trichloroacetate (TCA), [14C]dichloroacetate (DCA), and [14C]dichlorovinylcysteine (DCVC) in vivo. Association of radiolabel from [14C]TRI with hepatic proteins reached a maximum at 2 and 4 h in mouse and rat hepatic proteins, respectively. Association of radiolabel with renal proteins reached a maximum at 8 h in both species. An approach was developed based upon formation of protein adducts that release acetate and monochloroacetate (MCA) on acid hydrolysis. These adducts were found to be specifically associated with the activation of DCVC to reactive intermediates. Acetate and MCA were identified by using two different conditions of high-performance liquid chromatography (HPLC) separation with differing selectivity. Diethylmaleate and aminooxyacetic acid pretreatment inhibited the formation of these adducts from TRI, consistent with requirements for glutathione and beta-lyase. No evidence of these adducts was detected following [14C]TCA and [14C]DCA treatment. Renal acid-labile adduct formation from 25 mg/kg DCVC was approximately 12-fold greater in male B6C3F1 mice than in male F344 rats. They accounted for 7.8 and 4.6% of the total adducts to renal protein in rats and mice, respectively. Acid-labile adducts formed from 1000 mg/kg TRI were approximately two times greater in mice than rats. In this case, they accounted for 1.4 and 3.3% of the total adduct formed in renal proteins from TRI (corrected for metabolic incorporation), respectively. This greater dilution of adducts associated with DCVC in renal proteins of the rat suggests that covalent binding of TRI has less specificity for the DCVC pathway in rats than in mice.

Renal activation of trichloroethene and S-(1,2-dichlorovinyl)-L-cysteine and cell proliferative responses in the kidneys of F344 rats and B6C3F1 mice.

Covalent binding of reactive intermediates formed by renal beta-lyase activation of S-(1,2-dichlorovinyl)-L-cysteine (DCVC) has been suggested to be responsible for the greater renal sensitivity of rats than mice to the carcinogenic effects of chronic treatment with trichloroethene (TRI). Previous work demonstrated that the activation of DCVC results in acid-labile adducts to protein that can be distinguished from adducts formed by other pathways of TRI metabolism. By analyzing acid-labile adduct formation, the relationship between DCVC formation and activation from TRI and increases in rates of cell division in the kidneys of male F344 rats and B6C3F1 mice could be investigated. The delivered dose of DCVC from an oral dose of 1000 mg/kg TRI was approximately six times greater in rats than mice. However, renal activation of DCVC in mice was approximately 12 times greater than in rats. Therefore, the overall activation of TRI was about two times greater in mice than rats. Induction of cell replication in liver and kidney following doses of 1, 5, or 25 mg/kg DCVC or 1000 mg/kg TRI was also measured through the use of miniosmotic pumps that delivered BrdU subcutaneously for 3 d. Acid-labile adduct formation from DCVC and TRI displayed a consistent relationship with increased cell replication in mice and between mice and rats. Both cell replication and acid-labile adduct formation in rats given 25 mg/kg DCVC were approximately equal to that observed in mice given 1 mg/kg. Increased cell replication was not observed in rats receiving 1 or 5 mg/kg DCVC or 1000 mg/kg TRI, nor were there histological signs of nephrotoxicity. Thus, net activation of TRI by the cysteine S-conjugate pathway was found to be greater in mice than rats and these findings appeared related to differences in cell proliferative responses of the kidneys of the two species. Based on these data, it would appear that other factors must contribute to the greater sensitivity of the rat to the induction of renal carcinogenesis by TRI.

Semen leukocytes: friends or foes?

OBJECTIVE: To test the hypothesis that male reproductive tract leukocytes function in the elimination of abnormal spermatozoa from ejaculated semen. DESIGN: Semen specimens with > or = 2 x 10(6) nonspermatozoal cells/mL were examined for leukocytes and for mature sperm with ideal morphology. SETTING: Andrology laboratory of a Center of Assisted Reproductive Technology. RESULTS: Semen specimens with elevated concentrations of leukocytes contained a significantly higher frequency of sperm with ideal morphology than semen specimens with elevated numbers of immature germ cells and low numbers of leukocytes. CONCLUSIONS: The direct correlation between leukocyte density and sperm with ideal morphology supports the concept that sperm surveillance is a normal function of male reproductive tract leukocytes. Understanding such germ cell-leukocyte interactions may provide valuable new insights into immunologic control mechanisms in male reproductive tract tissues.

Management of recurrent priapism with epinephrine self-injection and gonadotropin-releasing hormone analogue.

A case of recurrent priapism in a young black man without sickle cell anemia is reported. Due to almost daily episodes of prolonged painful erections, the patient was instructed in intracorporeal injection using an epinephrine self-injection kit, which provided complete detumescence on 31 occasions. The patient refused surgical intervention and was treated with monthly intra-muscular gonadotropin-releasing hormone analogue. Priapism episodes completely abated by the second and final monthly gonadotropin-releasing hormone analogue injection without recurrence during 4 months of followup. Normal erectile function was maintained during and after gonadotropin-releasing hormone analogue therapy. Epinephrine self-injection and gonadotropin-releasing priapism.

Use of dynamic two-dimensional transesophageal echocardiography for renal cell carcinoma with cavoatrial tumor thrombus.

Renal cell carcinoma with inferior vena caval tumor thrombus extending to the level of the right atrium occurs in about 1% of all cases. Dynamic two-dimensional transesophageal echocardiography is a minimally invasive safe technique that can demonstrate preoperatively the cephalad extent of the cavoatrial tumor thrombus with an accuracy that appears equal to or better than that of any other method currently available. When used intraoperatively, it provides invaluable data to aid in the anesthetic and surgical management of the patient, obviating the need for and potential risk of placing a Swan-Ganz pulmonary artery catheter before complete removal of the tumor thrombus.

Adduction of hemoglobin and albumin in vivo by metabolites of trichloroethylene, trichloroacetate, and dichloroacetate in rats and mice.

Adducts to macromolecules from trichloroethylene formed by in vivo and in vitro metabolism have been reported by many investigators. We examined the in vivo adduction of the blood proteins hemoglobin (Hb) and albumin in rats and mice dosed orally with [14C]trichloroethylene ([14C]TRI) to explore the development of a protein adduct biomarker of TRI exposure. We also examined the adduction of these two proteins from doses of [14C]trichloroacetate (TCA) and [14C]dichloroacetate (DCA), two metabolites of TRI. Association of label with albumin peaked at 4-8 hr in the rat (2480 nmol eq TRI/mg protein) and 2-4 hr in the mouse (1580 nmol eq TRI/mg protein). The decay was exponential with a half-life consistent with that of rat or mouse albumin (approx 24 hr). The time course of label with Hb was characterized by an early plateau at 8 hr in rat (28 nmol eq TRI/mg protein), 4 hr in mouse (7 nmol eq TRI/mg protein), and followed by a slow steady increase, peaking at 120 hr (54 nmol eq TRI/mg protein, rat; 38 nmol eq TRI/mg protein, mouse). This apparent binding was linear with dose in the rat, but was convex in the mouse albumin (mouse Hb label was below detection at low dose). We also found that a portion of the irreversibly associated label, referred to by previous investigators as "binding," could be accounted for as metabolic incorporation of label into glycine and serine.(ABSTRACT TRUNCATED AT 250 WORDS)

Drug-induced pemphigus: autoantibodies directed against the pemphigus antigen complexes are present in penicillamine and captopril-induced pemphigus.

Pemphigus is an autoimmune blistering disease characterized by circulating autoantibodies directed against the keratinocyte cell surface. The two variants, pemphigus foliaceus and pemphigus vulgaris, can be distinguished at the molecular level by immunochemical studies. The large majority of patients with pemphigus develop the disease spontaneously; however, there is a small group of patients who develop pemphigus after treatment with certain medications, of which penicillamine and captopril are the best documented. Most patients with drug-induced pemphigus have circulating and/or tissue bound epidermal cell surface autoantibodies; however, the molecular specificity of these autoantibodies has not been studied. We performed immunoprecipitation studies utilizing extracts of 125I-labeled suction blister epidermis and the sera of three patients with drug-induced pemphigus foliaceus (two due to penicillamine and one due to captopril) and one patient with captopril-induced pemphigus vulgaris. We found that the three patients with drug-induced pemphigus foliaceus had circulating autoantibodies that are directed against the pemphigus foliaceus antigen complex and that the one patient with drug-induced pemphigus vulgaris had circulating autoantibodies that are directed against the pemphigus vulgaris antigen complex. This study demonstrates that autoantibodies from drug-induced pemphigus patients have the same antigenic specificity, on a molecular level, as do autoantibodies from other pemphigus patients.

A phase I study of recombinant human interleukin-2 and alpha-interferon-2a in patients with renal cell cancer, colorectal cancer, and malignant melanoma.

Preclinical data suggest synergy of interleukin-2 (IL-2) combined with alpha-interferon (IFN). In addition, toxicities of IL-2 may be decreased by intermittent continuous infusion. The purpose of this trial was to determine the maximum tolerated dose (MTD) of recombinant IL-2 combined with alpha-IFN in patients with renal cancer, colon cancer, melanoma, and malignant B-cell disease. IL-2 was given by continuous i.v. infusion at an initial dose of 5 X 10(5) units (U)/m2/d for 4 days plus IFN at 6 X 10(6) U/m2/d intramuscularly days 1 and 4 weekly for 4 weeks. Patients who achieved a response or stable disease received an additional 4 weeks of therapy. IL-2 doses were increased to 1, 2, 3, 5, and 7 X 10(6) U/m2/d with three to eight patients at each dose level, at each of the two participating institutions. The dose of IFN was 6 X 10(6) U/m2 days 1 and 4 for all but five patients whose IFN dose was doubled to 12 X 10(6) U/m2/d. Forty-three patients were entered on this study with 34 completing at least 4 weeks of therapy. Six patients were taken off study because of Grades III or IV pulmonary, neurologic, or cardiac toxicity; one for progressive disease; one for CNS metastases, and one for personal reasons. All of the toxicities were reversible. Chills and fever were universal, especially on days 1 and 4. Mild and moderate nausea, vomiting, diarrhea, anorexia, malaise, and cutaneous erythema were present in most patients. Fluid retention and occasional pleural effusions were observed at the higher IL-2 doses but were not dose-limiting. Significant hypotension associated with oliguria was seen, and these patients were treated with vasopressors and colloids. None of the patients required ICU admission. Thirty-four patients were evaluable for response. There were 4/18 (22%) renal cell patients who experienced a partial response. No responses were seen in patients with melanoma, lymphoma, or colorectal cancer. The combined debilitating symptoms of fatigue, diarrhea, hypotension, fluid retention, and anorexia defined the MTD as 5 X 10(6) U/m2/d of IL-2 and 6 X 10(6) U/m2 of alpha-IFN.

Resection of cavoatrial renal cell carcinoma employing total circulatory arrest.

Intracaval extension of renal cell carcinoma to the right atrium is a life-threatening presentation that may result in fatal tricuspid valve obstruction or pulmonary embolization. From 1981 to 1989 we treated 10 patients with such extension of tumor, the last 7 of whom underwent resection in which hypothermic circulatory arrest was used. No postoperative deaths, myocardial infarctions, or strokes occurred. Four patients were alive with no evidence of disease at 4, 10, 16, and 39 months after resection, and 1 patient was alive with pulmonary and spine metastases at 34 months after resection. Two patients died of metastatic disease at 7 and 12 months. In the absence of diffuse metastatic disease, lymph-node involvement, or invasion of contiguous organs, radical resection of cavoatrial hypernephroma may result in excellent palliation and possibly a cure.

Demonstration of an adhering-junction molecule (plakoglobin) in the autoantigens of pemphigus foliaceus and pemphigus vulgaris.

Pemphigus foliaceus and pemphigus vulgaris are skin diseases in which antibodies against the cell surface of keratinocytes destroy the adhesion between epidermal cells, producing blisters. Patients with pemphigus foliaceus have antibodies to a complex of three polypeptides of 260, 160, and 85 kd (the foliaceus complex), whereas patients with pemphigus vulgaris have antibodies to a complex of 210-kd, 130-kd, and 85-kd polypeptides (the vulgaris complex). The 160-kd polypeptide of the foliaceus complex has been identified as desmoglein, a desmosomal glycoprotein. We suspected that the 85-kd component in both these antigenic complexes might be plakoglobin, another molecule in the adhering junctions of cells. To characterize these antigenic complexes, we used the serum of five patients with pemphigus foliaceus, that of four patients with pemphigus vulgaris, and monoclonal antiplakoglobin antibodies. We found that monoclonal antibodies to plakoglobin immunoprecipitated the 85-kd polypeptide from the dissociated foliaceus and vulgaris complexes and precipitated both complexes from epidermal extracts. Serum from patients with pemphigus foliaceus or pemphigus vulgaris (but not from four normal controls) bound desmoglein and the 130-kd polypeptide, respectively, showing that these peptides (and not plakoglobin) are the antigenic binding sites in these disorders. We conclude that plakoglobin, a protein of the adhering junctions of epidermal cells, is the 85-kd molecule in the antigenic complexes found in both pemphigus foliaceus and pemphigus vulgaris, although it is not the binding site in either disorder.