[Effect of human decidua mesenchymal stem cells-derived exosomes on the function of high glucose-induced senescent human dermal fibroblasts and its possible mechanism].

Objective: To establish a high glucose senescent model of human dermal fibroblasts (HDFs), and to investigate the effects of exosomes derived from human decidua mesenchymal stem cells (dMSCs) on the proliferation, migration, and apoptosis of senescent HDFs and possible mechanism. Methods: The experimental research method was used. From January to March 2021, discarded foreskin tissue was collected for isolation and culture of primary HDFs from 4 male phimosis patients (aged 18-22 years) admitted for circumcision in the Fourth Medical Center of the PLA General Hospital. The 6th passage of HDFs were taken and divided into low glucose group and high glucose group according to the random number table, and subsequently cultured in low-glucose complete medium and high-glucose complete medium, respectively, with medium changed every 72 h without subculturing. After 10 days of culture, the cells were taken and measured for cellular senescence using the ß-galactosidase kit at 24 h after seeding; the expression of senescence-related proteins p16 and p53 was assessed by Western blotting at 48 h after seeding; cell proliferation was detected at 24, 48, and 72 h after seeding using the cell counting kit 8 (CCK-8) method; the cell proliferation was evaluated by 5-ethynyl-2'-deoxyuridine (EdU) staining method, cell cycle and apoptosis were measured by flow cytometry after 48 h of seeding; Transwell experiment was used for the calculation of cell migration rate at 24 h after seeding. The human dMSCs were taken and cultured for 48-72 h from which the exosomes were extracted by differential high speed centrifugal method. The morphology of dMSC exosomes was observed by transmission electron microscopy, the particle size distribution of dMSC exosomes was measured by nanoparticle tracking analysis, and the expression of dMSC-exosomes marker proteins CD9 and tumor susceptibility gene101 (TSG101) were detected by Western blotting. The dMSC exosomes and high-glucose complete medium-induced senescent HDFs were co-cultured for 24 hours, then PKH67 kit was used to detect the uptake of exosomes by HDFs. High-glucose complete medium-induced senescent HDFs were taken and divided into high glucose alone group, high glucose+low concentration of exosomes group, and high glucose+high concentration of exosomes group according to the same method above. The high-glucose complete medium with equal volume of phosphate buffered saline, dMSC exosomes with final concentration of 50 µg/mL, and dMSC exosomes with final concentration of 100 µg/mL were added to the corresponding groups for conventional cell culture, respectively. After grouped, the cell proliferation, cell cycle and apoptosis as well as cell migration were detected by CCK-8 method and EdU staining method, flow cytometry, and Transwell experiment at the corresponding time points as before, respectively. Based on the previous results, high-glucose complete medium-induced senescent HDFs were taken and divided into high glucose alone group and high glucose+high concentration of exosomes group for the same treatment. After being grouped and cultured for 48 h, real-time fluorescent quantitative polymerase chain reaction was used to evaluate the mRNA expression of senescent-related microRNA (miR)-145-5p, miR-498, miR-503-5p, calcium/calmodulin dependent protein kinase 1D (CAMK1D), phosphates and tensin homologue deleted on chromosome ten (PTEN) gene, and Cyclin D1 in high glucose alone group and high glucose+high concentration of exosomes group. Data were statistically analyzed with analysis of variance for factorial design, one-way analysis of variance, least significant difference t test, and independent sample t test. Results: At 24 h after seeding, the rate of ß-galactosidase-positive staining of HDF in high glucose group was (38.4±4.2)%, which was significantly higher than (16.5±2.2)% of low glucose group (t=4.65, P<0.01). At 48 h after seeding, the expression levels of senescence-related proteins p16 and p53 both were significantly higher in HDFs of high glucose group than those in low glucose group (with t values of 11.85 and 3.02, respectively, P<0.05 or P<0.01). At 0, 24, 48, and 72 h after seeding, the cell proliferation viability of HDFs in high glucose group was all significantly lower than in low glucose group (with t values of 4.13, 9.90, and 15.12, respectively, P<0.01). At 48 h after seeding, the rate of EdU-positive staining of HDFs in high glucose group was obviously lower than that of low glucose group (t=3.83, P<0.05). At 48 h after seeding, the percentage of G2/M+S subpopulations in three subpopulations (G0/G1, S, and G2/M) of HDF cycle was significantly lower in high glucose group than that in low glucose group (t=8.74, P<0.01). At 24 h after seeding, the number of HDFs migrated through the filter membrane to the lower chamber was 37±6 in high glucose group, which was significantly less than 74±7 in low glucose group (t=8.42, P<0.01). At 48 h after seeding, the HDF apoptosis rate was significantly higher in high glucose group than in low glucose group (t=8.48, P<0.01). The dMSC exosomes were cup-shaped or round vesicles with well-defined edges and uniform size distribution. The size of dMSC exosomes was basically in the range of 80-200 nm. Exosomal markers including CD9 and TSG101 were positively presented on the dMSC exosomes. After being co-cultured for 24 hours, the dMSC exosomes were taken up intracellularly by HDFs and mainly distributed around the nucleus of HDFs. After being grouped and cultured for 24, 48, and 72 h, the HDF proliferation viabilities in high glucose+low concentration of exosomes group and high glucose+high concentration of exosomes group were both significantly higher than in high glucose alone group (with t values of 6.36, 6.10, 7.76, 8.92, 12.17, and 10.74, respectively, P<0.01), the HDF proliferation viability in high glucose+high concentration of exosomes group was significantly higher than in high glucose+low concentration of exosomes group (with t values of 7.92, 4.82, and 4.72, respectively, P<0.01). After being grouped and cultured for 48 h, the percentages of EdU-positive HDFs in high glucose+low concentration of exosomes group and high glucose+high concentration of exosomes group were both significantly higher than in high glucose alone group (with t values of 5.32 and 9.88, respectively, P<0.01), the percentage of EdU-positive HDFs in high glucose+high concentration of exosomes group was notably higher than in high glucose+low concentration of exosomes group (t=5.27, P<0.01). After being grouped and cultured for 48 h, the proportion of G0/G1 subpopulation in both high glucose+low concentration of exosomes group and high glucose+high concentration of exosomes group was distinctly lower (with t values of 3.81 and 4.31, respectively, P<0.05), while the proportion of G2/M+S subpopulation was markedly higher (with t values of 3.81, 4.31, respectively, P<0.05) than in high glucose alone group. After being grouped and cultured for 24 h, the number of HDFs migrated through the filter membrane in both high glucose+low concentration of exosomes group and high glucose+high concentration of exosomes group was significantly higher than in high glucose alone group (with t values of 10.14 and 13.39, respectively, P<0.01), the number of HDFs migrated through the filter membrane in high glucose+high concentration of exosomes group was significantly increased than in high glucose+low concentration of exosomes group (t=6.27, P<0.01). After being grouped and cultured for 48 h, the HDF apoptosis rates in high glucose+low concentration of exosomes group and high glucose+high concentration of exosomes group were both significantly lower than in high glucose alone group (with t values of 3.72 and 5.53, respectively, P<0.05 or P<0.01). After being grouped and cultured for 48 h, compared with those in high glucose alone group, the mRNA expression levels of miR-145-5p and miR-498 were both obviously higher (with t values of 13.03 and 8.90, respectively, P<0.01), while the mRNA expression level of miR-503-5p was significantly lower (t=3.85, P<0.05) in high glucose+high concentration of exosomes group. After being grouped and cultured for 48 h, compared with those in high glucose alone group, the mRNA expression levels of CAMK1D and PTEN gene were both significantly lower (with t values of 8.83 and 5.97, respectively, P<0.01), while the mRNA expression level of Cyclin D1 was significantly higher in high glucose+high concentration of exosomes group (t=4.03, P<0.05). Conclusions: The dMSC exosomes are capable of improving cell proliferation and migration, and inhibiting cell apoptosis of high-glucose senescent HDFs. This may be related to the mechanism by which the increased expressions of intracellular miR-145-5p and miR-498 inhibit the expression of CAMK1D and PTEN gene, and the decreased expression of miR-503-5p promote the expression of Cyclin D1.

Correction: Deacetylation of HSPA5 by HDAC6 leads to GP78-mediated HSPA5 ubiquitination at K447 and suppresses metastasis of breast cancer.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Prucalopride inhibits lung cancer cell proliferation, invasion, and migration through blocking of the PI3K/AKT/mTor signaling pathway.

Lung cancer is the main cause of cancer incidence and mortality around the world. Prucalopride is an agonist for the 5-hydroxytryptamine 4 receptor, but it was unknown whether prucalopride could be used to treat lung cancer. To investigate the biological effects of prucalopride on proliferation, apoptosis, invasion, and migration of lung cancer cells, and its underlying molecular mechanism in the progression of lung cancer, we performed this study. The Cell Counting Kit 8 assay was used to measure the proliferation of A549/A427 lung cancer cells treated with prucalopride. Transwell assay was applied to evaluate cell invasion and migration. Cell apoptosis was detected by flow cytometry and Western blot analyses. The expression levels of related proteins in the PI3K/AKT/mTor signaling pathway were analyzed by Western blotting. Prucalopride inhibited the proliferation, invasion, and migration of A549/A427 human lung cancer cells. It also induced autophagy and apoptosis and decreased the expression of the phosphorylated protein kinase B (AKT) and mammalian target of rapamycin (mTor) in these cells. This study implied an inhibitory role for prucalopride in the progression of human lung cancer.

miR-520h is crucial for DAPK2 regulation and breast cancer progression.

This corrects the article DOI: 10.1038/onc.2015.168.

Deacetylation of HSPA5 by HDAC6 leads to GP78-mediated HSPA5 ubiquitination at K447 and suppresses metastasis of breast cancer.

Heat-shock protein 5 (HSPA5) is a marker for poor prognosis in breast cancer patients and has an important role in cancer progression, including promoting drug resistance and metastasis. In this study, we identify that the specific lysine residue 447 (K447) of HSPA5 could be modified with polyubiquitin for subsequent degradation through the ubiquitin proteasomal system, leading to the suppression of cell migration and invasion of breast cancer. We further found that GP78, an E3 ubiquitin ligase, interacted with the C-terminal region of HSPA5 and mediated HSPA5 ubiquitination and degradation. Knock down of GP78 significantly increased the expression of HSPA5 and enhanced migration/invasive ability of breast cancer cells. Knock down of histone deacetylase-6 (HDAC6) increased the acetylation of HSPA5 at lysine residues 353 (K353) and reduced GP78-mediated ubiquitination of HSPA5 at K447 and then increased cell migration/invasion. In addition, we demonstrate that E3 ubiquitin ligase GP78 preferentially binds to deacetylated HSPA5. Notably, the expression levels of GP78 inversely correlated with HSPA5 levels in breast cancer patients. Patients with low GP78 expression significantly correlated with invasiveness of breast cancer, advanced tumor stages and poor clinical outcome. Taken together, our results provide new mechanistic insights into the understanding that deacetylation of HSPA5 by HDAC6 facilitates GP78-mediated HSPA5 ubiquitination and suggest that post-translational regulation of HSPA5 protein is critical for HSPA5-mediated metastatic properties of breast cancer.

miR-520h is crucial for DAPK2 regulation and breast cancer progression.

MicroRNAs (miRNAs) are small RNAs that suppress gene expression by their interaction with 3'untranslated region of specific target mRNAs. Although the dysregulation of miRNAs has been identified in human cancer, only a few of these miRNAs have been functionally documented in breast cancer. Thus, defining the important miRNA and functional target involved in chemoresistance is an urgent need for human breast cancer treatment. In this study, we, for the first time, identified a key role of miRNA 520h (miR-520h) in drug resistance. Through protecting cells from paclitaxel-induced apoptosis, expression of miR-520h promoted the drug resistance of human breast cancer cells. Bioinformatics prediction, compensatory mutation and functional validation further confirmed the essential role of miR-520h-suppressed Death-associated protein kinase 2 (DAPK2) expression, as restoring DAPK2 abolished miR-520h-promoted drug resistance, and knockdown of DAPK2 mitigated cell death caused by the depletion of miR-520h. Furthermore, we observed that higher level of miR-520h is associated with poor prognosis and lymph node metastasis in human breast cancer patients. These results show that miR-520h is not only an independent prognostic factor, but is also a potential functional target for future applications in cancer therapeutics.

MiR-520h-mediated FOXC2 regulation is critical for inhibition of lung cancer progression by resveratrol.

Resveratrol, a phytochemical found in various plants and Chinese herbs, is associated with multiple tumor-suppressing activities, has been tested in clinical trials. However, the molecular mechanisms involved in resveratrol-mediated tumor suppressing activities are not yet completely defined. Here, we showed that treatment with resveratrol inhibited cell mobility through induction of the mesenchymal-epithelial transition (MET) in lung cancer cells. We also found that downregulation of FOXC2 (forkhead box C2) is critical for resveratrol-mediated suppression of tumor metastasis in an in vitro and in vivo models. We also identified a signal cascade, namely, resveratrol-∣miRNA-520h-∣PP2A/C-∣Akt → NF-κB → FOXC2, in which resveratrol inhibited the expression of FOXC2 through regulation of miRNA-520h-mediated signal cascade. This study identified a new miRNA-520h-related signal cascade involved in resveratrol-mediated tumor suppression activity and provide the clinical significances of miR-520h, PP2A/C and FOXC2 in lung cancer patients. Our results indicated a functional link between resveratrol-mediated miRNA-520h regulation and tumor suppressing ability, and provide a new insight into the role of resveratrol-induced molecular and epigenetic regulations in tumor suppression.

Development of an imaging-planning program for screen/film and computed radiography mammography for breasts with short chest wall to nipple distance.

OBJECTIVE: Imaging breasts with a short chest wall to nipple distance (CWND) using a traditional mammographic X-ray unit is a technical challenge for mammographers. The purpose of this study is the development of an imaging-planning program to assist in determination of imaging parameters of screen/film (SF) and computed radiography (CR) mammography for short CWND breasts. METHODS: A traditional mammographic X-ray unit (Mammomat 3000, Siemens, Munich, Germany) was employed. The imaging-planning program was developed by combining the compressed breast thickness correction, the equivalent polymethylmethacrylate thickness assessment for breasts and the tube loading (mAs) measurement. Both phantom exposures and a total of 597 exposures were used for examining the imaging-planning program. RESULTS: Results of the phantom study show that the tube loading rapidly decreased with the CWND when the automatic exposure control (AEC) detector was not fully covered by the phantom. For patient exposures with the AEC fully covered by breast tissue, the average fractional tube loadings, defined as the ratio of the predicted mAs using the imaging-planning program and mAs of the mammogram, were 1.10 and 1.07 for SF and CR mammograms, respectively. The predicted mAs values were comparable to the mAs values, as determined by the AEC. CONCLUSION: By applying the imaging-planning program in clinical practice, the experiential dependence of the mammographer for determination of the imaging parameters for short CWND breasts is minimised.

The role of the VEGF-C/VEGFR-3 axis in cancer progression.

Vascular endothelial growth factor (VEGF) receptor 3 (VEGFR-3) (also called VEGFR-3) is activated by its specific ligand, VEGF-C, which promotes cancer progression. The VEGF-C/VEGFR-3 axis is expressed not only by lymphatic endothelial cells but also by a variety of human tumour cells. Activation of the VEGF-C/VEGFR-3 axis in lymphatic endothelial cells can facilitate metastasis by increasing the formation of lymphatic vessels (lymphangiogenesis) within and around tumours. The VEGF-C/VEGFR-3 axis plays a critical role in leukaemic cell proliferation, survival, and resistance to chemotherapy. Moreover, activation of the VEGF-C/VEGFR-3 axis in several types of solid tumours enhances cancer cell mobility and invasion capabilities, promoting cancer cell metastasis. In this review, we discuss the novel function and molecular mechanism of the VEGF-C/VEGFR-3 axis in cancer progression.

The anti-apoptotic role of interleukin-6 in human cervical cancer is mediated by up-regulation of Mcl-1 through a PI 3-K/Akt pathway.

Interleukin-6 (IL-6), a multifunctional cytokine, has recently been implicated in human cervical cancer, though the mechanism remains elusive. This study demonstrates that the anti-apoptotic protein Mcl-1 and IL-6 was concomitantly expressed in human cervical cancer tissues and cell lines, but not in normal cervix tissues. Upon IL-6 treatment, Mcl-1, but not other Bcl-2 family members, was rapidly up-regulated peaking at 4-8 h in human cervical cancer C33A cells. Supporting this observation, using anti-IL-6 or anti-IL-6 receptor antibody to interrupt the IL-6 autocrine loop in SiHa cells significantly reduced cellular level of Mcl-1. This study hypothesizes that the expression of Mcl-1 in cervical cancer cells is regulated by IL-6. The matter of which signaling pathways transduced by IL-6 is responsible for the Mcl-1 up-regulation is further investigated herein. Blocking the STAT3 or MAPK pathway with dominant-negative mutant STAT3F or the MEK inhibitor PD98059 failed to inhibit IL-6-mediated Mcl-1 expression. Meanwhile, the IL-6-induced Mcl-1 up-regulation was effectively abolished by treatment with PI 3-K inhibitors, LY294002. Additionally, overexpression of dominant-negative (dn) Akt in C33A cells could inhibit the IL-6-induced increase of Mcl-1. Finally, overexpression of IL-6 in C33A cells caused a markable resistance to apoptosis induced by doxorubicin or cisplatin. Transient transfection of IL-6-overexpressed cells with a mcl-1 antisense vector, leading to the attenuation of their apoptosis-resistant activity. In conclusion, the data herein suggest that IL-6 regulated the mcl-1 expression via a PI 3-K/Akt-dependent pathway that may facilitate the oncogenesis of human cervical cancer by modulating the apoptosis threshold.

Vascular endothelial cell growth factors promote the in vitro development of rat photoreceptor cells.

We have identified and characterized a novel trophic effect of vascular endothelial cell growth factor (VEGF) on photoreceptor cells. Treatment of retinal cultures, derived from postnatal day 1 (P1) rats, with VEGF-2 resulted in a dose- and time-dependent increase in the level of rhodopsin protein, as determined by ELISA assay. After 7-9 d of treatment the VEGF-1 or VEGF-2, at a concentration of 10 ng/ml, induced a 200-300% increase in rhodopsin protein and a 220% increase in the number of rhodopsin-immunopositive cells. Treatment with VEGF-2 induced a 250% increase in the number of syntaxin-immunopositive cells and a 67% increase in high-affinity GABA uptake, both markers for amacrine cells. In contrast, there was no increase in the non-neuronal cell populations. VEGF-2 induced an approximately 300% increase in the number of bromodeoxyuridine-labeled (BrdU) retinal cells within 48 hr of treatment. After 3 d in culture both the basal and stimulated levels of BrdU incorporation were reduced, suggesting that the proliferative effect of VEGF was restricted developmentally. Furthermore, there was a developmentally dependent increase in the mitogenic response to VEGF-2, with retinal cultures derived from E15, E20, or P1 animals demonstrating a 50, 100, and 300% increase in thymidine incorporation, respectively. However, VEGF treatment resulted in an increase in the number of rhodopsin-immunopositive cells only when the cultures were derived from P1 animals. Therefore, retinal progenitor cells appear to be targets for VEGF, and thus VEGF may be involved in the regulation of the early developmental program of retinal neurogenesis.

Endoscopic management of skull base osteoradionecrosis.

OBJECTIVE: Osteoradionecrosis is one of the most serious complications in radiotherapy of nasopharyngeal carcinoma. We describe a new endoscopic approach to resolve resultant skull base osteoradionecrosis. The objective of this study is to evaluate the efficacy of endoscopic management of skull base osteoradionecrosis. STUDY DESIGN: A prospective study of the outcome of endoscopic management for patients with skull base osteoradionecrosis. METHODS: Between 1994 and 1998 six patients who had irradiation previously for nasopharyngeal carcinoma had skull base osteoradionecrosis. A sinoscopic approach was applied for diagnosis and sequestrectomy. This diagnosis was based on the criterion of exposed necrotic bone after removing all crust in the nasopharynx and further confirmed on pathological examination after sequestrectomy. Effective cure was defined as intact mucosal coverage without any ulcer or exposed necrotic bone observed in the nasopharynx and the absence of antecedent accompanying symptoms after management. RESULTS: Six patients (10%) were symptom free. Five (83.3%) patients had effective cure. There was no surgical morbidity or mortality. CONCLUSION: Endoscopic sequestrectomy is a justified approach to skull base osteoradionecrosis.

Suramin analogs inhibit human angiogenesis in vitro.

BACKGROUND: Suramin is a polysulfonated naphthylurea that inhibits tumor cell proliferation and angiogenesis, but the widespread use of this drug has been limited by significant neurologic toxicity. A series of suramin analogs that may exhibit less toxicity in vivo have been synthesized. We hypothesized that these novel analogs would have antiangiogenic properties equal to or greater than those of suramin when evaluated in an in vitro human placental vein angiogenesis model. METHODS: Human placental veins (n = 72 per group) were cultured in a 0.3% fibrin clot for a period of 14 days. Three suramin analogs (NF 145, NF 248, NF 293) and suramin were tested at 56 and 560 microM concentrations to determine their effect on the development of an angiogenic response. Experiments were repeated for each analog on veins from three different placentas. The percentage of wells that initiated an angiogenic response was calculated and compared with initiation in a control group (n = 141). RESULTS: The three suramin analogs inhibited angiogenesis in a dose-dependent fashion, with all compounds exhibiting near-complete inhibition of angiogenesis at 560 microM. The effects of these analogs were equal to or greater than those of suramin. CONCLUSION: Suramin analogs with structural alterations inhibit human angiogenesis at concentrations equivalent to those seen in vivo. These analogs may be more effective antiangiogenic agents than suramin and may have less potential for toxicity.

Production of monoclonal antibodies using recombinant baculovirus displaying gp64-fusion proteins.

Generation of protein immunogens is often a rate-limiting step in the production of monoclonal antibodies (Mabs). Expressing domains of proteins as fusions to the baculovirus surface glycoprotein gp64 displays foreign proteins on the surface of the virion. Antigen is produced by inserting a gene fragment in-frame between the signal sequence and the mature protein domain of the gp64 nucleotide sequence. This method allows immunization with whole virus, eliminating the need for purification of target antigens. Affinity-matured Mabs to the human nuclear receptors LXRbeta and FXR have been produced using baculovirus particles displaying gp64/nuclear receptor fusion proteins as the immunizing agent. Immunizations were performed directly with pelleted virus using the Repetitive Immunization Multiple Sites (RIMMS) immunization strategy for rapid Mab production. All Mabs were identified using insect cells infected with the immunizing virus. Characterization of these antibodies shows them to be class-switched and specific for LXRbeta or FXR. Additionally, high affinity antibodies that recognize gp64 and neutralize baculovirus infection of insect cells were isolated. Use of the recombinant baculovirus gp64 display system makes possible the production of Mabs once a partial DNA sequence is known. This allows the generation of antibodies prior to the isolation of purified protein, in turn providing antibodies to facilitate purification, characterization and immunolocalization of proteins.

Replication-associated activities of purified human papillomavirus type 11 E1 helicase.

Replication of human papillomavirus type11 (HPV11) requires both the E1 and the E2 proteins. E1 is structurally and functionally similar to SV40 large T-antigen and is a DNA helicase/NTPase that binds to the origin of replication and initiates viral DNA replication. The biochemical characterization of HPV E1 is incompletely documented in the literature in part because of difficulties in expressing and purifying the protein. Herein, we report a method for the overexpression of full-length, untagged E1 (73.5 kDa) in baculovirus-infected Trichoplusia ni insect cells and the purification to homogeneity using a two-step procedure. The purified protein is a nonspecific NTPase that hydrolyzes ATP, dATP, UTP, or GTP equally well. Point mutations were made in the putative NTPase domain to verify that the activities observed were encoded by E1. Purified mutant D523N had negligible ATPase and helicase activities but retained DNA-binding activity. Sedimentation equilibrium ultracentrifugation and glycerol gradient centrifugation demonstrated that the wild-type protein is primarily a hexamer in its purified form. Secondary structure determination by circular dichroism revealed a large percentage of alpha-helical structure consistent with secondary structure predictions. These data define a fundamental set of biochemical and kinetic parameters for HPV E1 which are a critical prerequisite to future mechanistic studies of the enzyme.

Production and characterization of an estrogen receptor beta subtype-specific mouse monoclonal antibody.

An important step in differentiating the unique physiological roles of the alpha and beta forms of estrogen receptor is to determine the precise expression pattern of each of these receptors. We report the generation and characterization of a murine IgG1 monoclonal antibody (MAb), ER15.64A that is ERbeta subtype-specific and capable of recognizing full-length human ERbeta as well as all of its known protein isoforms. ER15.64A, raised against a ERbeta peptide (aa2-18)-keyhole limpet hemocyanine conjugate, reacted to the immunizing peptide and the full-length E. coli expressed ERbeta in ELISA and BIAcore assays. It also immunostained nuclei of Sf9 insect cells that were infected with an ERbeta-baculovirus. In Western analysis, ER15.64A recognized ERbeta1 and ERbeta2 proteins from a reticulocyte in vitro transcription/translation preparation. This antibody did not cross-react with recombinant ERalpha in ELISA, BIAcore, immunocytochemistry, or Western blot analysis. The specificity of ER15.64A should make this antibody a useful tool for monitoring expression of ERbeta and its isoforms at the protein level and should aid in distinguishing the pattern of ERbeta receptor expression from that of ERalpha.

Expression of wild-type estrogen receptor beta and variant isoforms in human breast cancer.

It has been shown in previous studies that a variety of estrogen receptor (ER) beta mRNA transcripts are expressed in human breast cancer cell lines and tumors. To complement the RNA expression studies, we have developed ER-beta-specific antibodies to characterize ER-beta protein expression in breast cancer cell lines and tumors. Monoclonal antibodies were made against a peptide representing the first 18 amino acids of the longest ER-beta open reading frame reported to date, and polyclonal antibodies were made against a peptide within the ER-beta B domain. By Western blot analysis, we show that ER-beta protein is expressed in all cancer cell lines tested and in three of five breast tumor samples. The breast cancer cell lines showed variation in the size of the expressed ER-beta protein. The longest form detected was consistent with the 530-amino acid, full-length ER-beta sequence. Shorter ER-beta isoforms were detected in the ER-alpha-negative MDA-MB-231 and MDA-MB-435 breast cancer cell lines, likely corresponding to previously described COOH-terminal RNA variant isoforms.

Specific sequence elements are required for the expression of functional tumor necrosis factor-alpha-converting enzyme (TACE).

The tumor necrosis factor-alpha-converting enzyme (TACE) is a membrane-anchored zinc metalloprotease involved in precursor tumor necrosis factor-alpha secretion. We designed a series of constructs containing full-length human TACE and several truncate forms for overexpression in insect cells. Here, we demonstrate that full-length TACE is expressed in insect cells inefficiently: only minor amounts of this enzyme are converted from an inactive precursor to the mature, functional form. Removal of the cytoplasmic and transmembrane domains resulted in the efficient secretion of mature, active TACE. Further removal of the cysteine-rich domain located between the catalytic and transmembrane domains resulted in the secretion of mature catalytic domain in association with the precursor (pro) domain. This complex was inactive and function was only restored after dissociation of the complex by dilution or treatment with 4-aminophenylmercuric acetate. Therefore, the pro domain of TACE is an inhibitor of the catalytic domain, and the cysteine-rich domain appears to play a role in the release of the pro domain. Insect cells failed to secrete a deletion mutant encoding the catalytic domain but lacking the inhibitory pro domain. This truncate was inactive and extensively degraded intracellularly, suggesting that the pro domain is required for the secretion of functional TACE.

Systematic management of osteoradionecrosis in the head and neck.

OBJECTIVES: Osteoradionecrosis is one of the most serious and devastating complications of radiotherapy. The proper management of osteoradionecrosis is currently undetermined. The objective of this study is to evaluate the treatment results of a systematic approach to osteoradionecrosis. STUDY DESIGN: A prospective study of a systematic approach to osteoradionecrosis in the head and neck area was undertaken. METHODS: From July 1993 to June 1998, 33 cases of osteoradionecrosis in the head and neck area were treated using a systematic approach that combined sequestrectomy and hyperbaric oxygen therapy. RESULTS: Seven (21%) had recurrent cancer. The control rate of the other 26 osteoradionecrosis cases was 77% (20/26). CONCLUSIONS: Persistent osteoradionecrosis, despite diligent radical treatment, raises the suspicion of recurrent cancer. Extensive osteoradionecrosis with a multiple discharging fistula, a large area of exposed necrotic bone, or a coexistent fracture should be treated primarily with radical sequestrectomy and microvascular free flap reconstruction. Surgery still plays a major role in controlling osteoradionecrosis, and hyperbaric oxygen therapy is adjuvant.

Cloning and characterization of human estrogen receptor beta isoforms.

Multiple transcripts which arise from the human estrogen receptor beta (ER beta) gene have been characterized. Three full length isoforms of the hER beta gene, designated hER beta 1-3, were identified in a testis cDNA library. An additional two isoforms, designated hER beta 4 and hER beta 5, were identified by PCR amplification from testis cDNA and from the MDA-MB 435 cell line. hER beta 1 corresponds to the previously described hER beta. All five isoforms diverge at a common position within the predicted helix 10 of the ligand binding domain of hER beta, with nucleotide sequences consistent with differential exon usage. The hER beta isoform mRNAs displayed a differential pattern of expression in human tissues and in tumor cell lines when analyzed by RT-PCR. Further characterization of the three full length isoforms, hER beta 1-3, by in vitro band shift studies indicated that the isoforms were able to form DNA-binding homodimers and heterodimers with each other and with the ER alpha subtype.