Functional interaction of human Cdc37 with the androgen receptor but not with the glucocorticoid receptor

Cdc37 is a molecular chaperone closely associated with the folding of protein kinases. Results from studies using a yeast model system showed that it was also important for activation of the human androgen receptor (AR). Based on results from the yeast model system (Fliss, A. E., Fang, Y., Boschelli, F., and Caplan, A. J. (1997) Mol. Biol. Cell 8, 2501-2509), we initiated studies to address whether AR and Cdc37 interact with each other in animal cell systems. Our results show that Cdc37 binds to AR but not to glucocorticoid receptors (GR) synthesized in rabbit reticulocyte lysates. This binding occurs via the ligand-binding domain of the AR in a manner that is partially dependent on Hsp90 and the presence of hormone. Further studies using the yeast system showed that Cdc37 is not interchangeable with Hsp90, suggesting that it functions at a distinct step in the activation pathway. Expression of a dominant negative form of Cdc37 in animal cells down-regulates full-length AR but has very little effect on an AR truncation lacking the ligand-binding domain or full-length GR. These results reveal differences in the mechanisms by which AR and GR become active transcription factors and strengthen the notion that Cdc37 has a wider range of polypeptide clients than was realized previously.

Dendritic cells armed with anti-CD3 mAbs reduce pulmonary metastases, prolong survival, and engender antitumor effector cells demonstrable by adoptive transfer

BACKGROUND

Dendritic cells (DCs) pulsed with tumor cells or peptides are effective antitumor agents in a number of tumor models. In light of our earlier demonstration that T-cell signaling via the CD3 proteins induces cytolytic activity and constrains tumor progression, we equipped DCs pulsed with tumor cells with anti-CD3 mAbs and tested their antitumor efficacy in a murine renal cell cancer pulmonary metastasis model.

METHODS

We investigated the antitumor efficacy of DCs pulsed with whole irradiated tumor cells (DC/R) or DCs pulsed with irradiated tumor cells and armed with anti-CD3 mAbs (DC/R/anti-CD3 mAbs). Experimental end points included the number of pulmonary metastases and survival of tumor-inoculated mice.

RESULTS

Our studies demonstrate that arming tumor-pulsed DCs with anti-CD3 mAbs results in a superior outcome compared to that from tumor-pulsed DCs alone in terms of reduction in the number of pulmonary metastases and survival times. Furthermore, adoptive transfer experiments revealed that the splenocytes from DC/R/anti-CD3 mAbs-treated mice are superior to splenocytes from DC/R-treated mice in reducing renal cancer pulmonary metastases in severe combined immunodeficient (SCID) beige mice.

CONCLUSION

Our data suggest that the therapeutic efficacy of DCs pulsed with tumor cells can be augmented by arming them with anti-CD3 mAbs. DC-based treatment regimens that currently are being pursued in clinical trials might be improved by equipping such cells with anti-CD3 mAbs.

Strain-dependent variability in immune response to chicken riboflavin carrier protein in mice with different haplotypes

Active immunization of fertile female mice, rats and sub-human primates with linearized chicken riboflavin carrier protein (RCP) curtailed pregnancy suggesting that sequence-specific RCP antibodies interfere with fertilization/early embryo development. To investigate the genetic basis of variations in immunogenecity, antibody response to reduced and carboxymethylated RCP (RCM-RCP) was studied in different strains of mice of independent H-2 haplotypes. Among these, AKR (H-2k) were low or non-responders. Measurement of antibody titers in hyperimmune sera showed that among responder strains of mice, C57BL/6 (H-2b) and BALB/c (H-2d) generated higher levels of antibody compared to mice of SJLJ (H-2S). The relative affinities of these antibodies also varied depending upon the strain, with BALB/c mice showing highest affinity. Epitope mapping by pepscan ELISA revealed significant variability in determinant-specific antibody populations, with SJLJ strain lacking antibodies to N-terminal half of RCP sequence. However, four immunodominant sequential epitopes (residues 100-107, 134-141, 174-181 and 200-207) common to all the three strains of mice have been identified. Binding to these regions was not haplotype restricted although there were qualitative differences in recognition patterns. Present investigations have shown that site-specific antibodies directed towards any one of the four epitopic regions comprising of residues 3-24, 64-83, 130-147 and 200-219 in chicken RCP sequence effectively interfered with pregnancy establishment in female BALB/c mice. This implies the propensity of RCP antibodies to curtail pregnancy in the other two responder mouse strains also.

Active immunization against riboflavin carrier protein results in peri-implantation embryonic loss leading to pregnancy termination in rats: use of alternate adjuvants

To investigate the mechanism of pregnancy termination following immuno-neutralization of riboflavin carrier protein (RCP) and to use acceptable adjuvants, we actively immunized female rats with reduced and carboxymethylated RCP (RCM-RCP) using various adjuvants (during primary immunization) such as sodium phthalylated lipopolysaccharide (SPLPS), purified S. typhi outer membrane proteins (porins) and a combination of them. Rats (5-14 per group) were immunized with alugel adsorbed RCM-RCP (100 microg/dose) either alone or with SPLPS or porins or SPLPS+porins. Control animals received RCM-RCP emulsified with Fruend's completelincomplete adjuvants (FCA/FIA). All animals received five boosters at intervals of 21 days. The lowest (4 X 10(-3)) and the highest (> 70 X 10(-3)) anti-RCM-RCP antibody titers were observed in alugel adsorbed-RCM-RCP group and control groups, respectively. Immunized animals showed reduced fertility following 3rd, 4th and 5th boosters. Reduction in fertility was 30-60% in alugel adsorbed RCM-RCP group, 90-100% in FCA-RCM-RCP group and 80-90% in SPLPS+porins group. Fertility reduction was not strictly correlatable with the serum antibody titers. RCP-specific IgG could be localized in the uterine endometrial glands and luminal epithelial cells in the immunized animals. Animals in the FCA/FIA group showed abnormal implantation/resorption sites and their histological sections showed degenerated embryos. But, day 5 preimplantation embryos were normal. These results show that (a) SPLPS+porins can be used as adjuvants in place of FCA/FIA for active immunization against RCM-RCP and (b) early termination of pregnancy in the immunized animals is due largely to the failure of normal embryo implantation.

Neural cell response to multiple novel sites on laminin-1

The basement membrane protein laminin-1 is a potent stimulator of neurite outgrowth for a variety of neuronal cell types. Previous studies have identified neurite outgrowth activity in several distinct regions of the laminin-1 molecule. In this study, 545 overlapping 12- to 14-mer synthetic peptides, corresponding to most of the amino acid sequence of the alpha1, beta1, and gamma1 chains of laminin-1, were screened for cell attachment and neurite outgrowth activity using primary cultures of mouse cerebellar granule neurons and two neuronal cell lines. We identified 48 peptides derived from novel regions of the laminin-1 molecule that were positive for neural cell adhesion activity. Only the cerebellar cells were found to have true neurite outgrowth activity with certain of the peptides, whereas some peptides induced short spike-like process with the cell lines. Although 23 of these peptides were active on all 3 cell types screened, 25 others showed cell-type specificity in their activity. These studies show that (1) there are multiple and distinct sites on laminin-1 for cell adhesion and neurite-like outgrowth and (2) that there are neural cell-type-specific active domains. The multiple active sites found explains, in part, the potent activity of laminin-1 on neurite outgrowth.

Inhibition of p38 MAP kinase activity up-regulates multiple MAP kinase pathways and potentiates 1,25-dihydroxyvitamin D(3)-induced differentiation of human leukemia HL60 cells

Differentiation therapy for neoplastic diseases has potential for supplementing existing treatment modalities but its implementation has been slow. One of the reasons is the lack of full understanding of the complexities of cellular pathways through which signals for differentiation lead to cell maturation. This was addressed in this study using HL60 cells, a well-established model of differentiation of neoplastic cells. SB 203580 and SB 202190, specific inhibitors of a signaling protein p38 MAP kinase, were found to markedly accelerate monocytic differentiation of HL60 cells induced by low concentrations of 1,25-dihydroxyvitamin D(3) (1,25D(3)). Surprisingly, inhibition of p38 activity resulted in sustained enhancement of p38 phosphorylation and of its in vitro activity in the absence of the inhibitor, indicating up-regulation of the upstream components of the p38 pathway. In addition, SB 203580 or SB 202190 treatment of HL60 cells resulted in a prolonged activation of the JNK and, to a lesser extent, the ERK pathways. The data are consistent with the hypothesis that in HL60 cells an interruption of a negative feedback loop from a p38 target activates a common regulator of multiple MAPK pathways. The possibility also exists that JNK and/or ERK pathways amplify a differentiation signal provided by 1,25D(3).

Content analysis of critical incidents to redesign a university walk-in clinic

The UCLA walk-in clinic was scheduled to move into a new building in late 1997. This prompted the reevaluation of its existing service delivery system. A study was conducted among patients to understand their expectations and perceptions of the clinic's performance. The study was successful in identifying trends and problems and it was instrumental in developing proposals for a new patient flow system to be implemented in the new facility.

Control of estrogen receptor ligand binding by Hsp90

The molecular chaperone Hsp90 interacts with unliganded steroid hormone receptors and regulates their activity. We have analyzed the function of yeast and mammalian Hsp90 in regulating the ability of the human estrogen receptor (ER) to bind ligands in vivo and in vitro. Using the yeast system, we show that the ER expressed in several different hsp82 mutant strains binds reduced amounts of the synthetic estrogen diethylstilbestrol compared to the wild type. This defect in hormone binding occurs without any significant change in the steady state levels of ER protein. To analyze the role of mammalian Hsp90, we synthesized the human ER in rabbit reticulocyte lysates containing geldanamycin, an Hsp90 inhibitor. At low concentrations of geldanamycin we observed reduced levels of hormone binding by the ER. At higher concentrations, we found reduced synthesis of the receptor. These data indicate that Hsp90 functions to maintain the ER in a high affinity hormone-binding conformation.

Specific association of increased cyclin-dependent kinase 5 expression with monocytic lineage of differentiation of human leukemia HL60 cells

Hematopoietic cell differentiation takes place in phenotypically recognizable stages characterized by morphology as well as by the expression of enzymes and surface markers. It is recognized that differentiation results from an interaction of environmental cues, such as cytokines and hormones, with internal cellular programs, but the precise mechanisms are not entirely clear. HL60 cells, a human acute myeloid leukemia (AML) cell line with promyelocytic features, provide a model for such studies because they behave like stem cells, which can differentiate into two different lineages, granulocytic or monocytic/macrophage, depending on the inducer. Protein levels and kinase activity of cyclin-dependent kinase 5 (Cdk5) were reported [F. Chen and G. P. Studzinski (1999) Exp. Cell Res. 249, 422, 1999] to increase in HL60 cells induced to monocytic differentiation by 1alpha,25-dihydroxyvitamin D3 (1,25D3), but the specificity of the association of Cdk5 with the monocytic phenotype has not been established. We show here that up-regulation of Cdk5 does not occur in granulocytic differentiation, whereas inhibition of Cdk5 activity by olomoucine, or its expression by a plasmid construct expressing antisense Cdk5, switches the 1,25D3-induced monocytic phenotype (a combination of positive nonspecific esterase reaction, expression of the CD14 marker, and morphology) to general myeloid phenotype (positive nitro-blue tetrazolium reaction, CD11b marker and morphology). The transcriptional up-regulation of Cdk5 by 1,25D3 was not inhibited by olomoucine. These findings show that in human myeloid cells up-regulation of Cdk5 is specifically associated with the monocytic phenotype.

Predictors of glycemic control in children with type 1 diabetes: the importance of race

Diabetes is a common cause of kidney failure and blindness among young adults, particularly of African-American descent. Since glycemic control is a predictor of diabetes complications, we evaluated the impact of multiple factors including a special multidisciplinary management program on glycosylated hemoglobin in children with Type 1 diabetes. Data was collected from pediatric diabetes clinics in New Orleans, LA and Baltimore, MD. In New Orleans, hemoglobin A(1c) was higher in African-American patients 12. 5+/-3.3% (n=71) vs. 10.7+/-2.1% (n=80) in Caucasian children, p<0. 0001. Longer duration of diabetes was also associated with higher hemoglobin A(1c) in both races. The effect of race on hemoglobin A(1c) was independent of the influence of sex, insurance status, body mass index (BMI) z-score, and number of clinic visits. Covariate analysis with mean blood glucose levels indicated that higher hemoglobin A(1c) was attributable to higher mean blood glucose levels in African-American children. From the Baltimore data, a multidisciplinary intervention program led to improved total glycosylated hemoglobin for Caucasian patients but not for African-American children. Poorer glycemic control of African-American children is likely to predispose them to a higher likelihood of developing microvascular complications as they mature. Standard hospital-based multidisciplinary programming for diabetes management may have limited effectiveness in improving glycemic control of African-American children with diabetes. Innovative intervention programs are needed for these high-risk patients.

Ectopic expression of truncated Sp1 transcription factor prolongs the S phase and reduces the growth rate

The role of the transcription factor Sp1 in cell growth and survival was investigated by induced expression of its DNA-binding C-terminal fragment. Transfection of a constitutively expressed Sp1-170C plasmid construct into HeLa cells failed to produce viable clones, suggesting that this peptide interferes with cell growth. However, transfection with the muristerone A-inducible vector system produced four clones with low levels of expression of Sp1-170C. Muristerone A transiently induced higher levels of Sp1-170C, and this was accompanied by a reduced growth rate and prolongation of the S phase of the cell cycle. This is the first report that a dominant negative Sp1 can affect the cell cycle.

Management of tongue base obstruction in obstructive sleep apnoea syndrome

Studies have shown that the obstruction in OSA is more often than not multicentric. Tongue base obstruction is relatively more difficult to diagnose accurately and treat effectively. In this presentation, an effort is made to suggest two methods of management of this problem. One deals with the surgical management and the second, an alternative non-surgical method.

Phase-1 studies of malariotherapy for HIV infecton

OBJECTIVE

To determine whether malariotherapy (an old therapy for treatment of neurosyphilis) improves some clinical and laboratory parameters of HIV-positive patients without iatrogenic complications.

METHODS

Total 8 asymptomatic HIV-1 positive subjects whose CD4 cell counts were over 250 x 10(6) cells/L were selected for the phase-1 studies of malariotherapy and were intravenously injected Plasmodia vivax to induce artificial malaria. Malaria was terminated with chloroquine after 10 to approximately 20 malarial fever episodes. Cell-bound CD4 levels were measured by APAAP (a solid-phase enzyme essay) and levels of neopterin (NPT), beta-2-microglobulin (B2M), soluble tumor necrosis factor receptor-2 (sTNF-RII), interleukin-2 (IL-2) and HIV P24 antigen were measured by ELISA. Patients were followed up to 24 to approximately 30 months.

RESULTS

CD4 levels increased in 5, NPT decreased in 7 of 8 patients; IL-2 increased in 5 of 6 patients after malariotherapy. The total trends of B2M and sTNF-RII basically remained stable. HIV P24 antigen remained undetectable in 6, remained detectably low level in 1 and experienced increase in 1 of 8 patients after malariotherapy. No any severe complications occurred in all 8 patients.

CONCLUSIONS

The results indicate that malariotherapy basically is safe for HIV infection and it seems that the therapy improves some immunological parameters of HIV patients.

Domain requirements of DnaJ-like (Hsp40) molecular chaperones in the activation of a steroid hormone receptor

DnaJ-like proteins function in association with Hsp70 molecular chaperones to facilitate protein folding. We previously demonstrated that a yeast DnaJ-like protein, Ydj1p, was important for activation of heterologously expressed steroid hormone receptors (Caplan, A. J., Langley, E., Wilson, E. M., and Vidal, J. (1995) J. Biol. Chem. 270, 5251-5257). In the present study, we analyzed Ydj1p function by assaying hormone binding to the human androgen receptor (AR) heterologously expressed in yeast. We analyzed hormone binding in strains that were wild type or deleted for the YDJ1 gene. In the deletion mutant, the AR did not bind hormone to the same extent as the wild type. Introduction of mutant forms of Ydj1p to the deletion strain revealed that the J-domain is necessary but not sufficient for Ydj1p action, and that other domains of the protein are also functionally important. Of three human DnaJ-like proteins introduced into the deletion mutant, only Hdj2, which displays full domain conservation with Ydj1p, suppressed the hormone binding defect of the deletion mutant. By comparison of the domains shared by these three human proteins, and with mutants of Ydj1p that were functional, it was deduced that the cysteine-rich zinc binding domain is important for Hdj2/Ydj1p action in hormone receptor function. A model for the mechanism of DnaJ-like protein action is discussed.

Nature and determinants of customer expectations of service recovery in health care

Service recovery refers to the service provider's response to a dissatisfied customer. This article proposes a model of customer expectations of service recovery in health care services. The model discusses two types of service recovery expectations: will and should. An exploratory study indicates that industry reputation and personal experiences drive customers' "will-expectations" of service recovery while "should-expectations" can be explained via norm, fairness, social contract and hospitality theories.

Binding of a dimeric derivative of vancomycin to L-Lys-D-Ala-D-lactate in solution and at a surface

BACKGROUND

The emergence of bacteria that are resistant to vancomycin (V), a glycopeptide antibiotic, results from the replacement of the carboxy-terminal D-Ala-D-Ala of bacterial cell wall precursors by D-Ala-D-lactate. Recently, it has been demonstrated that covalent dimeric variants of V are active against vancomycin-resistant enterococci (VRE). To study the contribution of divalency to the activities of these variants, we modeled the interactions of V and a dimeric V with L-Lys-D-Ala-D-lactate, an analog of the cell-wall precursors of the vancomycin-resistant bacteria.

RESULTS

A dimeric derivative of V (V-Rd-V) was found to be much more effective than V in inhibiting the growth of VRE. The interactions of V and V-Rd-V with a monomeric lactate ligand - diacetyl-L-Lys-D-Ala-D-lactate (Ac2KDADLac) - and a dimeric derivative of L-Lys-D-Ala-D-lactate (Lac-R'd-Lac) in solution have been examined using isothermal titration calorimetry and UV spectroscopy titrations; the results reveal that V-Rd-V binds Lac-R'd-Lac approximately 40 times more tightly than V binds Ac2KDADLac. Binding of V and of V-Rd-V to Nalpha-Ac-L-Lys-D-Ala-D-lactate presented on the surface of mixed self-assembled monolayers (SAMs) of alkanethiolates on gold indicates that the apparent off-rate for dissociation of V-Rd-V from the surface is much slower than that of V from the same surface.

CONCLUSIONS

The results are compatible with the hypothesis that divalency is responsible for tight binding, which correlates with small values of minimum inhibitory concentrations of V and V-Rd-V.

Metarrhizium anisopliae as a cause of sinusitis in immunocompetent hosts

Metarrhizium anisopliae is a common pathogen of insects and has even been used to control insect populations. It is rarely isolated from human or animal sources, but recently, there have been three reported cases of disease, two in humans and one in a cat. We present our experience with five isolates from human sources, including two that were the apparent causes of two cases of sinusitis in immunocompetent hosts. The first patient was a 36-year-old male with frontal and ethmoid sinusitis, and the second was a 79-year-old female with chronic sinusitis. Both patients underwent surgery, and pathology of the surgical specimens revealed branching hyphae. Cultures grew only Metarrhizium species. Neither patient received antifungal therapy, and both did well postoperatively. The other three isolates were cultured from bronchoalveolar lavage specimens but were not felt to be clinically significant. Antifungal susceptibility testing using the National Committee for Clinical Laboratory Standards macrobroth method revealed that all isolates were resistant to amphotericin B, 5-flucytosine, and fluconazole. Itraconazole and newer azole compounds were more active. Metarrhizium species may cause disease in humans, even those without evidence of immunosuppression, and are apparently highly resistant to amphotericin B in vitro.

Postradiation morphea

We describe a 54-year-old woman who developed right breast morphea after radiotherapy following a lumpectomy for infiltrating lobular carcinoma. Skin biopsy confirmed the histological features of morphea. Treatment was initiated with both topical and intralesional steroid, resulting in marked improvement. Morphea following radiotherapy is an infrequently recognized phenomenon. However, when diagnosed early it may be effectively managed with local steroid treatment.