Advances in Design and Development of Lumi-Solve: A Novel Drug-Eluting Photo-Angioplasty Device

PURPOSE

The Lumi-Solve photo-angioplasty drug eluting balloon catheter (DEBc) may afford safety advantages over current DEBc. Lumi-Solve utilises the guidewire (GW) port and lumen to deliver fibre-optic UV365nm light to the angioplasty balloon which may be problematic. We explore and evaluate alternative Lumi-Solve design options to circumvent fibre-optic use of the GW port and lumen which may enhance efficacy and clinical utility.

METHODS

Effects of guidewire shadowing (GWS) on visible and UV365nm light transmission were evaluated and modelled in-silico. To evaluate the effect of a dedicated intra-balloon fibre-optic port, modified angioplasty balloons and sections of translucent polyethylene terephthalate (PET) GW port tubing were utilised. Investigation of the effect of GWS on chemical and biological photo-activation of balloon surface drug was performed utilising LCMS analysis and inhibition of histone deacetylase activity (HDACi) was measured in human umbilical vein endothelial cells (HUVEC).

RESULTS

Parallel fibre-optic and GW port configurations generated a GWS of approximately 18.0% of the evaluable balloon surface area and attenuated both visible and UV light intensity by 20.0-25.0% and reduced chemical photo-activation of balloon surface drug and HDACi by at least 40-45%. Alternative fibre-optic port configurations including a spiral design significantly mitigated GWS effects on UV light transmission.

CONCLUSIONS

To avoid use of the GW port and its associated complications a dedicated third port and lumen for the Lumi-Solve fibre-optic may be required. To maximize balloon surface chemical and biological photo-activation, non-parallel, intra-balloon, fibre-optic lumen trajectories, including a spiral design may be useful.

Serum interleukin-4 is elevated in clinical drug-induced liver injury

BACKGROUND

Drug-induced liver injury (DILI) remains a challenging diagnosis due to an absence of specific biomarkers. DILI due to volatile anaesthetics (VA-DILI) is characterised by trifluoroacetyl and CYP2E1 antibodies, but may not be seen for weeks after injury. Interleukin-4 (IL-4) may be involved in the production of these antibodies and may serve as a clinically useful early biomarker of VA-DILI.

AIM

To prospectively compare serum IL-4 levels between patients who develop VA-DILI and controls following exposure to the volatile anaesthetic.

METHODS

A nested case-control study of patients exposed to VA during surgery was conducted. Thirteen DILI cases were identified from the original cohort, and 26 controls were matched according to age, sex and VA agent. Serum samples were collected before and 48-96 h after VA exposure, and analysed for IL-4 using quantitative enzyme-linked immunosorbent assay techniques.

RESULTS

There was a statistically significant difference in serum IL-4 in post-VA samples between DILI cases and controls (control: 0.030 pg/mL, IQR: 0.030 - 0.030 pg/mL vs DILI: 0.044 pg/mL, IQR: 0.030 - 0.061 pg/mL; p = 0.039). A greater proportion of DILI cases had post-VA IL-4 levels above the assay lower limit of detection compared to controls (control: 23% vs DILI: 69%; p = 0.013).

CONCLUSION

IL-4 is a potential biomarker of DILI. Clinical diagnosis and understanding of DILI disease mechanisms may be improved by further investigation of novel biomarkers, and this IL-4 signal in serum is important as proof of concept for prospective study designs.

Lytic effects of water on cancer cells: Implications for post-operative irrigation

BACKGROUND

Intraoperative tumour spillage can be concerning during cancer excisions, given it can lead to tumour-cell re-implantation and local recurrence. Examples include bladder tumour recurrences post-transurethral resection, or peritoneal spillage during laparotomy/laparoscopy for bowel and ovarian cancers. One approach to reducing implantation is mechanical wash out of free-floating tumour cells. Irrigation with water may have additional effectiveness compared to iso-osmotic irrigants (e.g. saline) by causing osmotic cytolysis, but this is not well-characterised. This in vitro study aimed to ascertain the time-course of osmotic effects of water on various cancer cell lines to provide guidance for clinical usage.

METHODS

Assays were conducted on six cancer cell lines (bladder [HT1197, HT1376], colon [KM12, LIM2405], kidney [SKRC52], and ovarian [COV434]). Cells were exposed to water or 0.9% saline and cell counts were performed using a haemocytometer at 10, 20, 40, 60, 120 and 180 min. Cell viability was determined using Trypan Blue exclusion.

RESULTS

In all cell lines, exposure to water led to 100% cell lysis within a median time of 40 min (range 10-180 min), while exposure to saline led to a gradual decline in cell viability (median 50.2%, range 6.7%-100.0%) over 3 h, and did not result in complete cell lysis. An increase in osmotic gradient equivalent to a concentration of 5% NaCl was sufficient to impede the effects of water-mediated cell lysis.

CONCLUSION

Our studies suggest that water has a rapid osmolytic effect on cancer cells. The required exposure time to reach 0% cell viability varied between individual cell lines.

Imbalance of the renin-angiotensin system may contribute to inflammation and fibrosis in IBD: a novel therapeutic target?

OBJECTIVE

We evaluated the influence of the renin-angiotensin system (RAS) on intestinal inflammation and fibrosis.

DESIGN

Cultured human colonic myofibroblast proliferation and collagen secretion were assessed following treatment with angiotensin (Ang) II and Ang (1-7), their receptor antagonists candesartan and A779, and the ACE inhibitor captopril. Circulating and intestinal RAS components were evaluated in patients with and without IBD. Disease outcomes in patients with IBD treated with ACE inhibitors and angiotensin receptor blockers (ARBs) were assessed in retrospective studies.

RESULTS

Human colonic myofibroblast proliferation was reduced by Ang (1-7) in a dose-dependent manner (p<0.05). Ang II marginally but not significantly increased proliferation, an effect reversed by candesartan (p<0.001). Colonic myofibroblast collagen secretion was reduced by Ang (1-7) (p<0.05) and captopril (p<0.001), and was increased by Ang II (p<0.001). Patients with IBD had higher circulating renin (mean 25.4 vs 18.6 mIU/L, p=0.026) and ACE2:ACE ratio (mean 0.92 vs 0.69, p=0.015) than controls without IBD. RAS gene transcripts and peptides were identified in healthy and diseased bowels. Colonic mucosal Masson's trichrome staining correlated with Ang II (r=0.346, p=0.010) and inversely with ACE2 activity (r=-0.373, p=0.006). Patients with IBD who required surgery (1/37 vs 12/75, p=0.034) and hospitalisation (0/34 vs 8/68, p=0.049) over 2 years were less often treated with ACE inhibitors and ARBs than patients not requiring surgery or hospitalisation.

CONCLUSIONS

The RAS mediates fibrosis in human cell cultures, is expressed in the intestine and perturbed in intestinal inflammation, and agents targeting this system are associated with improved disease outcomes.

Identification of novel oncogenic events occurring early in prostate carcinogenesis using purified autologous malignant and non-malignant prostate epithelial cells

OBJECTIVE

To interrogate enriched prostate cancer cells and autologous non-malignant prostate epithelial cells from men with localized prostate cancer, in order to identify early oncogenic pathways.

PATIENTS AND METHODS

We collected malignant and matched non-malignant prostatectomy samples from men with adenocarcinoma involving two or more contiguous areas in only one lobe of the prostate. Tissue samples from both lobes were subjected to digestion and single-cell suspensions were prepared. Epithelial cell adhesion molecule-positive cells from cancerous and contralateral non-malignant (control) samples were isolated using magnetic beads, ensuring uniform populations were obtained for each donor. Unbiased RNA sequencing analysis was used to measure gene expression and for detection of transcribed mutations or splice variants that were over- or under-represented in malignant prostate epithelial cells relative to autologous control prostate epithelial cells.

RESULTS

From five patient samples we identified 17 genes that were altered in prostate cancer epithelial cells, with 82% of genes being downregulated. Three genes, TDRD1, ANGTL4, and CLDN3, were consistently upregulated in malignant tissue. Malignant cells from three of the five patients showed evidence of upregulated ERG signalling, however, only one of these contained a TMPRSS2-ERG rearrangement. We did not identify mutations, gene rearrangements, or splice variants that were consistent amongst the patients.

CONCLUSIONS

Events occurring early in prostate cancer oncogenesis in these samples were characterized by a predominant downregulation of gene expression along with upregulation of TDRD1, ANGTL4 and CLDN3. No consistent mutations or splice variants were observed, but upregulation of ERG signalling was seen both in the presence and absence of the classic TMPRSS2-ERG rearrangement.

The intestinal vitamin D receptor in inflammatory bowel disease: inverse correlation with inflammation but no relationship with circulating vitamin D status

BACKGROUND

The intestinal vitamin D receptor (VDR) remains poorly characterized in patients with inflammatory bowel disease (IBD).

METHODS

Colonoscopic biopsies and intestinal resection specimens from the terminal ileum, ascending and sigmoid colon, from patients with and without IBD, were analyzed for VDR mRNA quantification by polymerase chain reaction, and protein localization and semi-quantification by immunohistochemistry. The relationship between VDR and intestinal inflammation, serum 25(OH)D and oral vitamin D intake was elicited.

RESULTS

A total of 725 biopsies from 20 patients with Crohn's disease (CD), 15 with ulcerative colitis (UC) and 14 non-IBD controls who underwent colonoscopy were studied. VDR gene expression and protein staining intensity was similar across all three groups, and across the intestinal segments. Sigmoid colon VDR mRNA expression inversely correlated with faecal calprotectin (r = -0.64, p = 0.026) and histological score (r = -0.67, p = 0.006) in UC, and histological score (r = -0.58, p = 0.019) in patients with CD. VDR staining intensity was higher in quiescent than diseased segments. No relationship with serum 25(OH)D or oral vitamin D intake was noted. Immunohistochemical staining of 28 intestinal resection specimens from 15 patients (5 each with CD, UC and non-IBD controls) showed diffuse VDR staining in the mucosa, submucosa and circular muscle.

CONCLUSIONS

VDR transcript expression and protein staining intensity are inversely related to inflammation in IBD, but unrelated to serum 25(OH)D, and similar to non-IBD controls. Strategies to upregulate intestinal VDR, potentially translating to modulation of disease activity, require investigation.

Association of androgen receptor (AR) copy number gain with ARV7 expression and response to chemotherapy

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Background: Emerging data suggests that ARV7 mRNA (ARV7+) expression and AR copy number gain/amplification (AR+) are associated with resistance to androgen deprivation therapy. Most studies thus far have evaluated either AR copy number or ARV7 mRNA, but not both markers. It is likely that both markers are indicators of genomic changes that are seen in the prostate cancer cells in response to tumour evolution or treatment. Here we developed a digital droplet PCR (ddPCR) based assay to evaluate plasma ARV7 mRNA expression in the same samples used for AR copy number analysis in castrate resistant prostate cancer (CRPC). This assay was use to evaluate the role of AR+ and ARV7+ in CRPC using samples collected from multiple centers and correlated with outcome. Methods: We collected plasma samples from patients with CRPC treated with chemotherapy (C) or next generation androgen targeted agents (NAR) to evaluate circulating tumour DNA (ctDNA) for AR and plasma mRNA for ARV7. Some patients had sequential samples and we correlated PSA response (reduction PSA≥50 confirmed 3wks later (RR)) with AR and ARV7 status and clinical features. Results: A total of 52 samples were included from 26 patients, with matched samples from some patients at different time points. Of the CRPC patients, AR+ was seen in 70% (18/26), AR- in 30% (8/26), ARV7+ in 67% (12/18) and ARV7- in 33% (6/18). 75% (9/12) patients with AR+ also had ARV7+. In matched samples: 3/7 had change in AR status, 2/7 had change in ARV7 status, including 1 patient where both changed; and interestingly there was a group with no AR or ARV7 detected. Number of patients expressing both markers AR+/ARV7+ in 50% (9/18), AR+/ARV7- in 17% (3/18), AR-/ARV7+ 17% (3/18) and AR-/ARV7- in 11% (2/18). RR to C or NAR was 63% (12/19) for AR+ and 75% (9/12) for ARV7+ patients. In AR+ patients, response to NAR was 58% (12/16) but response to chemotherapy was 100% (5/5). Conclusions: AR gain/amplification in CRPC was associated with ARV7+ expression and leads to lower response to NAR compared to C. This approach can be used to undertake integrated DNA and mRNA analysis, has wide-scale utility and may be used for analysis of a larger number of circulating biomarkers.

Biological significance of novel populations of prostate cancer circulating tumor cells (CTC)

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Background: Decisions regarding selection and sequencing of treatment in advanced prostate cancer (PC) are often made empirically, without information on the PC molecular profile at the time of treatment. CTC provide real time information regarding contemporaneous biologically relevant cancer subtypes. Current assays often rely on EpCAM or other epithelial markers and may underestimate or exclude other CTC populations of clinical relevance. We devised a novel, simple, rapid and cheap method for isolation of CTC subsets including those without epithelial markers. Methods: Five mL of blood was processed as follows: CD45+ depletion (RosetteSep Human CD45 Depletion Cocktail, Stemcell Technologies); Ficoll centrifugation; antibody staining (mix of EpCAM-PE, PSMA-APC, N-cadherin-AF488, E-cadherin-PerCP/Cy5.5, CD45-APC-H7); Sytox Blue live/dead cell stain; followed by sorting (Becton Dickinson FACSAria Fusion cell sorter). Live cells were sorted into 4 categories denoted E, E+P, P, N (Table). N and P are not identifiable using existing conventional CTC techniques. CTC were assayed for prostate markers ( AR, FOLH1 (PSMA), KLK3 (PSA), TMPRSS2, AMACR) and malignant markers ( PTEN copy number) using digital droplet PCR. Results: Preliminary data are derived from 62 patient samples providing 47 sorted populations. Details are in the Table. Spiking experiments reliably identified as few as 10 CTC / 7.5 mL of blood. P cells were detected in all patients, often outnumbering sum of E and E+P; E and N were never co-expressed. P and N samples frequently expressed prostate markers. Only 1/27 showed no expression of any of these five prostate markers. PTEN deletion assays are in progress. Conclusions: “Unconventional” EpCAMneg CTC appear to be derived from PC and can be detected using broader cell selection criteria. These CTC may provide information on treatment resistance or escape mechanisms. [Table: see text]

Circulating estrogen receptor (ER) mutations and splice variants in men with advanced prostate cancer (APC)

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Background: Circulating DNA and RNA have been studied in APC as biomarkers of potential clinical significance. Candidates include androgen receptor amplification or emergence of splice variants. ER signalling has been associated with prostate cancer progression in vitro but blood-based detection of ER variants has not been studied. Methods: Men with APC were recruited for serial blood collection during routine management, from which cell-free DNA (cfDNA) and cell-free RNA (cfRNA) were extracted. Six well-described ERα mutations (E380Q, L536Q, Y537C, Y537S, Y537N & D538G) and six ER splice variants (ERα-66, ERα-36, ERβ1, ERβ2, ERβ4 & ERβ5) were quantitated using droplet digital polymerase chain reaction. These markers were explored in association with clinical and treatment variables using descriptive statistics. Results: 44 men were included for a total of 92 cfDNA and 94 cfRNA samples, with a median of 2 (range: 1-6) sequential samples per patient. Two mutations (E380Q & D538G) were detected in both cfDNA and cfRNA samples, and two (L536Q & Y537S) were detected in cfRNA samples only. The ER splice variants were widely detected in cfRNA samples, including in non-cancer controls. ERα-36 was detected at lower levels than the other splice variants investigated (p < 0.0001). Despite ubiquitous detection, the levels of splice variants altered consistently with analysis of the following clinical variables: during castration therapy; following castration resistance; and with number of previous treatments. No clear patterns of expression were observed for ER mutants. Serial sample analysis associated increased ERα-36 levels with response to docetaxel or abiraterone therapy. ERβ splice variant levels decreased with progression on all studied therapies. Development of E380Q and L536Q mutations was observed in patients with disease progression. Conclusions: We identified circulating ER mutants and splice variants in men with APC. These variants may be associated with previous treatment use, as well as disease progression on castration therapy or other APC treatments. Further work will explore their utility for predicting treatment response.

Vinorelbine Potently Induces Placental Cell Death, Does Not Harm Fertility and is a Potential Treatment for Ectopic Pregnancy

Ectopic pregnancies complicate 1–2 pregnancies and are a leading cause of maternal death. An effective oral drug therapy that replaces surgery might make its treatment safer, cheaper, simpler and therefore more widely accessible. The only current medical treatment offered to women is intramuscular methotrexate, but this only reliably resolves smaller ectopic pregnancies. As such, many ectopic pregnancies require surgical excision. We show that vinorelbine, an orally available chemotherapeutic agent, potently induced placental cell death but did not harm fertility in mice. Vinorelbine was 100–1000 times more potent than methotrexate in inducing placental cell death in vitro, and more potent than combination methotrexate and gefitinib (another proposed treatment for ectopic pregnancy being evaluated in phase III trials). Mechanistically, it caused microtubule condensation, blocked mitosis and activated the apoptosis cascade in placental cells. Vinorelbine was more efficacious than methotrexate ± gefitinib in reducing the volume of placental cell tumors xenografted subcutaneously in SCID mice. Mice exposed to vinorelbine and allowed to breed, following a four week washout period, displayed normal fertility, however long-term fertility was not assessed. Human Fallopian tubes treated with vinorelbine did not exhibit up-regulation of apoptosis molecules. Our findings show that placental cells appear sensitive to vinorelbine and it has potential as a tablet-only approach to treat ectopic pregnancy.

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We have identified vinorelbine, a well tolerated chemotherapeutic, as a potential therapeutic for ectopic pregnancy.

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Vinorelbine potently reduced placental cell viability in-vitro and in-vivo and proved more efficacious than the current medical therapeutic.

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Vinorelbine did not impact upon subsequent fertility in a mouse breeding model.

Ectopic pregnancy occurs when a conceptus implants outside of the womb. They are life threating and are a leading cause of maternal death in early pregnancy. Currently, the large majority of ectopic pregnancies are removed surgical, partly owing to the limited efficacy of the only available medical therapeutic, methotrexate. Here, we have identified a potential new medical therapeutic for ectopic pregnancy, vinorelbine. Vinorelbine, which is orally available chemotherapeutic, reduced placental cell viability both in-vitro and in-vivo and did not impact upon mice fertility in a breeding model. As such, vinorelbine may be an efficacious treatment for ectopic pregnancy and further human studies into its application are warranted.

Cell mates: paracrine and stromal targets for prostate cancer therapy

After many years of limited treatment options for patients with metastatic castration-resistant prostate cancer (mCRPC), multiple systemic therapies are now available, providing patients with significant improvements in survival, symptom control and bone health. Most of the recent advances in this area have been based on better understanding of mCRPC biology, particularly with respect to the key role of androgen receptor signalling. However, most therapies are targeted towards the malignant epithelial cell component of the cancer and it should not be forgotten that cancer cells exist in close and symbiotic relationships with other components of the tumour. Paracrine and stromal signals are often critical to the growth of the cancer and represent new potential therapeutic targets that are separate from the malignant epithelial cells. The stroma produces numerous growth factors, including vascular endothelial growth factor family members, platelet-derived growth factors and fibroblast growth factors, which are all critical for tumour growth. Targeting prostate-cancer-associated fibroblasts in order to destroy the physical and functional scaffold of a cancer is also a logical approach. The interaction between prostate cancer and the immune system remains an active topic of basic and clinical research, with cytokines, chemokines and growth factors being potential targets for therapy. The biology of epithelial-mesenchymal transition and of circulating tumour cells might also provide insight into new therapeutic targets.

Targeted nanoparticle delivery of doxorubicin into placental tissues to treat ectopic pregnancies

Abnormal trophoblast growth can cause life-threatening disorders such as ectopic pregnancy, choriocarcinoma, and placenta accreta. EnGeneIC Delivery Vehicles (EDVs) are nanocells that can promote tissue-specific delivery of drugs and may be useful to medically treat such disorders. The objective of this study was to determine whether EDVs loaded with the chemotherapeutic doxorubicin and targeting the epidermal growth factor receptor (EGFR, very highly expressed on the placental surface) can regress placental cells in vitro, ex vivo, and in vivo. In female SCID mice, EGFR-targeted EDVs induced greater inhibition of JEG-3 (choriocarcinoma cells) tumor xenografts, compared with EDVs targeting an irrelevant antigen (nontargeted EDVs) or naked doxorubicin. EGFR-targeted EDVs were more readily taken up by human placental explants ex vivo and induced increased apoptosis (M30 antibody) compared with nontargeted EDVs. In vitro, EGFR-targeted EDVs administered to JEG-3 cells resulted in a dose-dependent inhibition of cell viability, proliferation, and increased apoptosis, a finding confirmed by continuous monitoring by xCELLigence. In conclusion, EGFR-targeted EDVs loaded with doxorubicin significantly inhibited trophoblastic tumor cell growth in vivo and in vitro and induced significant cell death ex vivo, potentially mediated by increasing apoptosis and decreasing proliferation. EDVs may be a novel nanoparticle treatment for ectopic pregnancy and other disorders of trophoblast growth.

Proteomic changes in rat spermatogenesis in response to in vivo androgen manipulation; impact on meiotic cells

The production of mature sperm is reliant on androgen action within the testis, and it is well established that androgens act on receptors within the somatic Sertoli cells to stimulate male germ cell development. Mice lacking Sertoli cell androgen receptors (AR) show late meiotic germ cell arrest, suggesting Sertoli cells transduce the androgenic stimulus co-ordinating this essential step in spermatogenesis. This study aimed to identify germ cell proteins responsive to changes in testicular androgen levels and thereby elucidate mechanisms by which androgens regulate meiosis. Testicular androgen levels were suppressed for 9 weeks using testosterone and estradiol-filled silastic implants, followed by a short period of either further androgen suppression (via an AR antagonist) or the restoration of intratesticular testosterone levels. Comparative proteomics were performed on protein extracts from enriched meiotic cell preparations from adult rats undergoing androgen deprivation and replacement in vivo. Loss of androgenic stimulus caused changes in proteins with known roles in meiosis (including Nasp and Hsp70–2), apoptosis (including Diablo), cell signalling (including 14-3-3 isoforms), oxidative stress, DNA repair, and RNA processing. Immunostaining for oxidised DNA adducts confirmed spermatocytes undergo oxidative stress-induced DNA damage during androgen suppression. An increase in PCNA and an associated ubiquitin-conjugating enzyme (Ubc13) suggested a role for PCNA-mediated regulation of DNA repair pathways in spermatocytes. Changes in cytoplasmic SUMO1 localisation in spermatocytes were paralleled by changes in the levels of free SUMO1 and of a subunit of its activating complex, suggesting sumoylation in spermatocytes is modified by androgen action on Sertoli cells. We conclude that Sertoli cells, in response to androgens, modulate protein translation and post-translational events in spermatocytes that impact on their metabolism, survival, and completion of meiosis.

Stimulation of prostate cancer cell proliferation by bone-derived factors

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Background: Interactions between cancer cells and their microenvironment affect the establishment and metastasis of cancer. The most common site of prostate cancer (PC) metastasis is bone. This study examined the effects of selected factors known to be produced by bone stroma (EGF, aFGF, HGF, β-NGF, TGF-β, and TNFα) on the proliferation of PC cells. The effect of cell culture medium (CM) conditioned by osteoblasts (OBCM) was also examined.

Methods: The PC-derived cell lines PC3, LNCaP, and DU145 were used. Expression of receptors for the above-mentioned cytokines was assessed using real-time RT-PCR. After 5 days of continuous cytokine treatment, proliferation was assessed by MTS conversion, and cell survival and apoptosis was assessed by 7-AAD staining and flow cytometry. OBCM was generated using the HOS, MG63, and SaOs2 cell lines. CM from the HT1080 fibrosarcoma cell line was used as a non-bone control.

Results: The PC cell lines expressed receptors for all of the cytokines examined at the mRNA level. LNCaP cell proliferation was increased by aFGF and decreased by TGF-β. Treatment with TNFα decreased proliferation of all PC cell lines. These effects were not due to apoptosis. EGF, HGF, and β-NGF did not affect proliferation of any line despite receptor expression. OBCM increased proliferation of PC3 and DU145 cells but not LNCaP cells, while HT1080 CM did not affect proliferation of any line.

Conclusions: PC cells are able to respond to defined bone-derived factors and that the nature of this response varies between individual cancers. Acidic FGF increased proliferation of LNCaP cells while TGF-β and TNFα decreased proliferation of LNCaP and all cell lines, respectively; an effect not mediated by apoptosis. Current studies are examining the effect of these cytokines on other functional parameters (cell survival, adhesion and migration) and on primary PC epithelial cells.

No significant financial relationships to disclose.

Cancer/testis antigens can be immunological targets in clonogenic CD133+ melanoma cells

"Cancer stem cells" that resist conventional treatments may be a cause of therapeutic failure in melanoma. We report a subpopulation of clonogenic melanoma cells that are characterized by high prominin-1/CD133 expression in melanoma and melanoma cell lines. These cells have enhanced clonogenicity and self-renewal in vitro, and serve as a limited in vitro model for melanoma stem cells. In some cases clonogenic CD133(+) melanoma cells show increased expression of some cancer/testis (CT) antigens. The expression of NY-ESO-1 in an HLA-A2 expressing cell line allowed CD133(+) clonogenic melanoma cells to be targeted for killing in vitro by NY-ESO-1-specific CD8(+) T-lymphocytes. Our in vitro findings raise the hypothesis that if melanoma stem cells express CT antigens in vivo that immune targeting of these antigens may be a viable clinical strategy for the adjuvant treatment of melanoma.

Application of laser-capture microdissection to analysis of gene expression in the testis

The isolation and molecular analysis of highly purified cell populations from complex, heterogeneous tissues has been a challenge for many years. Spermatogenesis in the testis is a particularly difficult process to study given the unique multiple cellular associations within the seminiferous epithelium, making the isolation of specific cell types difficult. Laser-capture microdissection (LCM) is a recently developed technique that enables the isolation of individual cell populations from complex tissues. This technology has enhanced our ability to directly examine gene expression in enriched testicular cell populations by routine methods of gene expression analysis, such as real-time RT-PCR, differential display, and gene microarrays. The application of LCM has however introduced methodological hurdles that have not been encountered with more conventional molecular analyses of whole tissue. In particular, tissue handling (i.e. fixation, storage, and staining), consumables (e.g. slide choice), staining reagents (conventional H&E vs. fluorescence), extraction methods, and downstream applications have all required re-optimisation to facilitate differential gene expression analysis using the small amounts of material obtained using LCM. This review will discuss three critical issues that are essential for successful procurement of cells from testicular tissue sections; tissue morphology, capture success, and maintenance of molecular integrity. The importance of these issues will be discussed with specific reference to the two most commonly used LCM systems; the Arcturus PixCell IIe and PALM systems. The rat testis will be used as a model, and emphasis will be placed on issues of tissue handling, processing, and staining methods, including the application of fluorescence techniques to assist in the identification of cells of interest for the purposes of mRNA expression analysis.

Claudin-11 expression and localisation is regulated by androgens in rat Sertoli cells in vitro

Claudin-11 and occludin are protein components in tight junctions (TJs) between Sertoli cells which are important for the maintenance of the blood-testis barrier. Barrier formation occurs during puberty, with evidence suggesting hormonal regulation of both claudin-11 and occludin. This study aimed to investigate the regulation of claudin-11 and occludin mRNA expression by testosterone (T) and FSH and their immunolocalisation at rat Sertoli cell TJs in vitro, and to correlate any steroid regulation with the functional capacity of TJs. Sertoli cells formed functional TJs within 3 days as assessed by transepithelial electrical resistance (TER). Both T and dihydrotestosterone significantly (P < 0.01) increased TER twofold and claudin-11 mRNA two- to threefold within 3 days. FSH partially stimulated TER and claudin-11 mRNA, but estradiol had no effect. T also promoted claudin-11 localisation into extensive intercellular contacts. In contrast to claudin-11, Tand FSH did not change occludin mRNA expression, however, T promoted localisation of occludin at cell contacts in a similar manner to claudin-11. Addition of flutamide to T-stimulated cells caused a twofold decrease in both TER and claudin-11 mRNA expression, and resulted in the loss of both proteins from cell contacts. This effect was reversible following flutamide removal. It is concluded that androgens i) co-regulate claudin-11 mRNA expression and TER, implicating claudin-11 in TJ formation and ii) promote the localisation of claudin-11 and occludin at Sertoli cell contacts. Hence, the ability of androgens to maintain spermatogenesis in vivo is partly via their effects on TJ proteins and regulation of the blood-testis barrier.

FSH regulates the formation of adherens junctions and ectoplasmic specialisations between rat Sertoli cells in vitro and in vivo

Spermatogenesis is dependent on the ability of Sertoli cells to form mature junctions that maintain a unique environment within the seminiferous epithelium. Adjacent Sertoli cells form a junctional complex that includes classical adherens junctions and testis-specific ectoplasmic specialisations (ES). The regulation of inter-Sertoli cell junctions by the two main endocrine regulators of spermatogenesis, FSH and testosterone, is unclear. This study aimed to investigate the effects of FSH and testosterone on inter-Sertoli cell adherens junctions (as determined by immunolocalisation of cadherin, catenin and actin) and ES junctions (as determined by immunolocalisation of espin, actin and vinculin) in cultured immature Sertoli cells and GnRH-immunised adult rat testes given FSH or testosterone replacement in vivo. When hormones were absent in vitro, adherens junctions formed as discrete puncta between interdigitating, finger-like projections of Sertoli cells, but ES junctions were not present. The adherens junction puncta included actin filaments that were oriented perpendicularly to the Sertoli cell plasma membrane, but were not associated with the intermediate filament protein vimentin. When FSH was added in vitro, ES junctions formed, and adjacent adherens junction puncta fused into extensive adherens junction belts. After hormone suppression in vivo, ES junctions were absent, while FSH replacement restored ES junctions, as confirmed by electron microscopy and confocal analysis of ES-associated proteins. Testosterone alone did not affect adherens junctions or ES in vitro or in vivo. We conclude that FSH can regulate the formation of ES junctions and stimulate the organisation and orientation of extensive adherens junctions in Sertoli cells.

Stage-specific expression of genes associated with rat spermatogenesis: characterization by laser-capture microdissection and real-time polymerase chain reaction

Spermatogenesis in the rat consists of 14 unique morphologic cellular associations between Sertoli cells and developing germ cells within the seminiferous epithelium. The complexity of the cellular associations leads to difficulty in the isolation of individual cells at a defined stage of development for the study of their unique patterns of gene or protein expression. Thus, laser-capture microdissection is an ideal technique to permit such analysis. This study used laser-capture microdissection and real-time reverse transcription-polymerase chain reaction (RT-PCR) to quantitate the stage-specific expression of a series of genes of functional significance in hormonal regulation and cell-cell interactions in spermatogenesis, including cathepsin-L, CREM-tau, transition protein-1, androgen receptor, beta1-integrin, N-cadherin, and hypoxanthine phosphoribosyltransferase (HPRT). Frozen sections (10 micro m) were obtained from normal adult rat testes. Laser-capture microdissection (LCM) was used to capture all cells in cross-sections of seminiferous tubules that were grouped into stages I-V, VII-VIII, and IX-XIII. Transition protein-1 expression was lowest during stages I-V and increased 5.9-fold during stages VII-VIII and IX-XIII (P < 0.01). Cathepsin-L expression was highest during stages I-V and VII-VIII, falling 4.9-fold during stages IX-XIII (P < 0.05). Similarly, CREM-tau expression was highest during stages I-V and VII-VIII, falling 1.6-fold during stages IX-XIII (P < 0.05). A novel CREM-tau isoform lacking the phosphorylation domain was also characterized but was not stage-specific. beta1-Integrin, N-cadherin, and androgen receptor expression did not change between the spermatogenic stages examined. HPRT housekeeper expression was lowest during stages I-V but increased 1.5-fold during stages VII-VIII and IX-XIII (P < 0.05). This study is the first to apply LCM and real-time RT-PCR analysis to quantitate stage-specific changes in the expression of multiple genes in the seminiferous epithelium.

Structural determinants of aldosterone binding selectivity in the mineralocorticoid receptor

The structural determinants of aldosterone binding specificity in the mineralocorticoid receptor (MR) have not been determined. The MR has greatest sequence identity with the better characterized glucocorticoid receptor (GR), which is reflected in their overlapping ligand binding specificities. There must be subtle sequence differences that can account for the MR-specific binding of aldosterone and the shared binding of cortisol. To characterize ligand binding specificity, chimeras were made between the human MR and GR ligand-binding domains (LBDs). Three points were chosen as break points to generate a total of 16 different constructs. These chimeric LBDs were placed in a human GR expression vector containing the GR DNA-binding and N-terminal domains and assayed by co-transfection into CV-1 cells with the mouse mammary tumor virus-luciferase reporter plasmid. Binding of [(3)H]aldosterone and [(3)H]dexamethasone was also measured. All of the constructs that are potently activated by aldosterone contain amino acids 804-874 of the MR. The results of the ligand binding experiments using [(3)H]aldosterone were consistent with the transactivation assay. Cortisol activation of the chimeras was surprisingly complex. Constructs that are activated by cortisol contain either amino acids 804-874 and 932-984 of the MR or amino acids 598-668 and 726-777 of the GR. However, all of the chimeras retained the ability to bind the synthetic glucocorticoid [(3)H]dexamethasone, and cortisol was able to displace [(3)H]dexamethasone binding, suggesting that the differential effects of cortisol on transcriptional activation are caused by an effect that occurs downstream of ligand binding. These results identify a subregion of the MR LBD that confers specificity of aldosterone binding, which contrasts with cortisol binding where differential effects between chimeras appear to be mediated by interactions distal to ligand binding.

Reduced protein adsorption on plastics via direct plasma deposition of triethylene glycol monoallyl ether

The direct plasma-induced deposition of tri(ethylene glycol) monoallyl ether is reported. RF plasma polymerization of this monomer was carried out under both continuous wave (CW) and pulsed plasma operation. The major focus of this work was optimization of the degree of retention of the C-O-C bonds of the starting monomer during the deposition process. This successfully was accomplished using low RF power during the CW runs and low RF duty cycles during the pulsed plasma experiments. Spectroscopic analysis of the plasma films revealed a strong dependence of film composition on the RF power and duty cycles employed. In particular, an unusually high level of film chemistry compositional control was demonstrated for the pulsed plasma studies, with film composition varying in a steady, progressive fashion with sequential changes in the ratios of plasma on to plasma off times. This film chemistry controllability is demonstrated despite the relatively low volatility of the starting monomer. The utility of this plasma deposition approach in introducing polyethylene oxide (PEO) structures on solid substrates was evaluated via protein adsorption studies. Radiolabeled bovine albumin adsorption was studied on plasma-modified poly(ethylene teraphthalate) (PET) substrates. Dramatic reductions in both initial adsorption and retention of this protein were observed on PET samples having maximal PEO content relative to its adsorption on untreated PET surfaces. Good stability and adhesion of the plasma films to the underlying PET substrates were observed, as evidenced from prolonged immersion of plasma-treated surfaces in aqueous solution. Overall, the results obtained from the present work provide additional support for the utility of one-step plasma process to reduce biological fouling of surfaces via deposition of PEO surface units.