009. KALLIKREIN-RELATED PROTEASES AS NOVEL THERAPEUTIC TARGETS IN PROSTATE AND OVARIAN CANCER

The kallikrein-related (KLKs) peptidases are implicated in prostate and ovarian cancer invasion/metastasis via activation of growth factors, proteases and extracellular matrix degradation involved in. In our published work, we used cell biology approaches to show novel associations of KLK peptidases with processes indicative of metastasis and the potential of our novel sunflower trypsin inhibitor scaffold-engineered KLK4 inhibitor. Our current studies are directed towards discovering the precise KLK target proteins/substrates and the subsequent signalling pathways involved in these events in order to determine their therapeutic target potential. In this regard, we are using novel tissue engineered biomimetic 3D gel matrices to better mimic the in vivo micro-environment of prostate cancer cells especially in bone metastasis and peritoneal invasion in ovarian cancer. Pilot studies show that PC3 cells cultured on an osteoblast-derived bone matrix undergo an EMT-like change but remain dispersed on the cell surface. In contrast, LNCaP cells cluster aligning with the fibrillar structure as they invade into the bone matrix as typically seen in vivo. KLK4 proteolysis of the osteoblast-derived bone matrix has identified additional novel substrates. In addition, we are exploring the cell biology that underlies the reported high KLK4 or KLK7 levels associated with poorer outcome in women with epithelial ovarian cancer (EOC). Of note, KLK4 or KLK7 transfected SKOV3 EOC cells have increased chemoresistance to taxol and/or cisplastin suggesting a mechanism for this poor outcome. Furthermore, KLK7 transfected SKOV-3 cells form multicellular aggregates (MCA) in agarose suspension (a process indicative of peritoneal tumour cell spread seen in ascites fluid clinically) which can be reversed by a KLK7 blocking antibody indicating the critical role played by KLK7 in this event. These new paradigms are providing novel information on the role of KLK peptidases in prostate and ovarian cancer progression and their potential as novel therapeutic targets.

Feasibility of group follow-up visit for breast cancer survivors

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Background: The ASCO 2006 guidelines specify that regularly scheduled follow-up care of breast cancer survivors should be the standard. Follow up care is a “teachable moment” to train survivors in positive habits. A group visit model at the Cleveland Clinic proved feasible and improved patient satisfaction for other diseases. Our objectives include assessing the feasibility of an adapted group follow-up visit for the care of breast cancer patients and patient satisfaction. Methods: A feasibility study targeting breast cancer patients who completed primary therapy and were scheduled for a routine appointment. We mailed letters inviting patients to a follow-up group visit. Patients were divided into 3 groups, each scheduled for a separate (90–120 minute). During the first half of the visit, participants were divided into three groups; 5-minute physician exam, nurse review of medications and vital signs, and instruction by a social worker. Groups were rotated. During the second half the doctor, nurse, and social worker met with all participants in one room starting with an educational presentation about fatigue and exercise. Each participant was subsequently interviewed by the physician in the presence of their peers. Shared complaints were investigated first. Patients rated their satisfaction with the different parts of the visit on a scale of 1–5. Participants were surveyed pre- and post- education session and asked if they would participate again. Participants were allowed to bring a family member or friend. Results: 29 (29.6 %) out of 98 consented and 22 (22.5%) attended;10 in first visit, 5 in second visit and 7 in last visit. Average age 61±8, ranged from 46–72 years. Most participants were satisfied with all parts of the group visit, except two in the first group were less satisfied with the check in process and moving between rooms. Comparing the pre- vs. post- educational session surveys showed an improved understanding of the importance of fatigue or exercise. 17 (77%) out of 22 participants agreed to participate in another group visit. Conclusion: Group visit format is feasible and provides patient satisfaction.

No significant financial relationships to disclose.

Microarray analysis of formalin-fixed paraffin-embedded specimens shows distinct gene expression patterns in tumors containing the transforming growth factor beta receptor 6A polymorphism (TGFBR1*6A)

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Introduction: A frequent polymorphism of the type I transforming growth factor beta receptor (TGFBR1) is TGFBR1*6A (6A), which has a deletion of 3 CGC triplets coding for alanine within a 9-alanine (9A) repeat of TGFBR1 exon 1. 6A may act as a tumor susceptibility allele through switching TGF-beta growth inhibitory signals into growth stimulatory signals and also appears to be acquired in some cases by primary colon cancers and their liver metastases. Our aim in this study was to compare the gene expression profiles of colorectal tumors bearing the 6A and the more common 9A genotypes to discover pathways that might be differentially induced by the 6A polymorphism. Methods: 28 colorectal tumors with matched synchronous metastases and 23 non-metastatic colorectal tumors were analyzed for TGFBR1 exon 1 genotype by a PCR-based assay. Nine metastatic and 10 non-metastatic tumors were analyzed by gene expression microarrays. Following microdissection of paraffin-embedded specimens, RNA was isolated, amplified, labeled, and hybridized to Affymetrix U133 Plus 2.0 GeneChips. Results: Among the 28 primary metastatic tumors, 19 were 9A (68%), 8 were 9A/6A heterozygotes (29%) and 1 was a 6A homozygote (3%). There was 100% genotype correspondence with the matched metastases. Among the 23 non-metastatic tumors, 18 were 9A (78%), 3 were heterozygotes (13%) and 2 were 6A/6A (9%). Microarray analysis showed 578 differentially expressed genes in the metastatic tumors and 467 in the non-metastatic tumors between the 6A and 9A genotypes (p<0.01). Significant pathway deregulation between 9A and 6A genotypes included estrogen receptor signaling and histidine metabolism in the non-metastatic tumors and B cell receptor, GM-CSF, SAPK/JNK and IL-4 signaling in the metastatic tumors. Conclusion: Microarray analysis shows differentially expressed genes in the 6A genotype compared to 9A, with different deregulated pathways in metastatic and non-metastatic tumors. This alludes to 6A-specific downstream signaling effects, which may contribute to tumor development and progression.

No significant financial relationships to disclose.

Rapid identification of virulence genes in enterotoxigenic Escherichia coli isolates associated with diarrhoea in Queensland piggeries

OBJECTIVE

To identify virulence genes in enterotoxigenic E coli (ETEC) isolates associated with diarrhoea in neonatal, 1 to 3 week-old and weaned pigs in southeast Queensland.

DESIGN

Multiplex PCR and serotyping were applied to E coli isolates obtained over a 5-year period (1998-2002) from cases diagnosed at Toowoomba Veterinary Laboratory.

PROCEDURE

A total of 126 isolates from 25 different Queensland piggeries were tested for haemolytic activity on 5% sheep blood agar and by multiplex PCR for the presence of five commonly recognised fimbrial (F4, F5, F6, F41 and F18) and three enterotoxin genes (STa, STb, LT). A subset of 62 representative isolates were serotyped by slide agglutination. For comparative purposes, multiplex PCR was also performed on the DNA of 31 ETEC isolates from 9 serotypes originating from piggeries in southern New South Wales.

RESULTS

A total of 113 (89.7%) of the isolates from Queensland possessed ETEC virulence genes, including 14 of 15 isolates from neonatal pigs (93.3%), 18 of 23 isolates from 1 to 3 week old pigs (78.3%) and 81 of 88 isolates from weaned pigs (92.1%). F4:STa:STb:LT (serotype O149) was the most prevalent pathotype in neonatal and 1-3 week old pigs and F4:STa:STb:LT (serotype O149) and F18:STa:STb:LT (serotype O141) were most prevalent in weaned pigs. In comparison, isolates obtained from neonatal pigs from New South Wales belonged to a more diverse range of pathotypes and serotypes.

CONCLUSION

Multiplex PCR was a rapid and specific method for detecting the presence of ETEC virulence genes in porcine E coli isolates. For isolates obtained from cases of suspected colibacillosis in Queensland, growth of a heavy pure culture of haemolytic E coli was a sensitive prognostic indicator of the presence of ETEC virulence genes in the isolate. ETEC pathotypes and serotypes remained stable in Queensland piggeries over the five-year study period and appear to have changed little over the last three decades.

Phase I study of 506U78 administered on a consecutive 5-day schedule in children and adults with refractory hematologic malignancies

PURPOSE

A phase I study was conducted to determine the maximum-tolerated dose (MTD), toxicity profile, and pharmacokinetics of a novel purine nucleoside, nelarabine, a soluble prodrug of 9-beta-D-arabinosylguanine (araG; Nelarabine), in pediatric and adult patients with refractory hematologic malignancies.

PATIENTS AND METHODS

Between April 1994 and April 1997, 93 patients with refractory hematologic malignancies were treated with one to 16 cycles of study drug. Nelarabine was administered daily, as a 1-hour intravenous infusion for 5 consecutive days, every 21 to 28 days. First-cycle pharmacokinetic data, including plasma nelarabine and araG levels, were obtained on all patients treated. Intracellular phosphorylation of araG was studied in samples of leukemic blasts from selected patients.

RESULTS

The MTDs were defined at 60 mg/kg/dose and 40 mg/kg/dose daily x 5 days in children and adults, respectively. Dose-limiting toxicity (DLT) was neurologic in both children and adults. Myelosuppression and other significant organ toxicities did not occur. Pharmacokinetic parameters were similar in children and adults. Accumulation of araGTP in leukemic blasts was correlated with cytotoxic activity. The overall response rate was 31%. Major responses were seen in patients with T-cell malignancies, with 54% of patients with T-lineage acute lymphoblastic leukemia achieving a complete or partial response after one to two courses of drug.

CONCLUSION

Nelarabine is a novel nucleoside with significant cytotoxic activity against malignant T cells. DLT is neurologic. Phase II and III trials in patients with T-cell malignancies are encouraged.

Delay in starting treatment for tuberculosis in east London

In the United Kingdom there is little information about the delay between the onset of symptoms in patients with tuberculosis and the time it takes for them to be correctly diagnosed and treatment started. We have examined the duration and possible causes of such delay in our own district. The records of 93 patients were examined. Total delay in starting treatment was estimated as the time from the start of symptoms to commencement of chemotherapy. Patient delays were estimated from the time between the start of symptoms to the time taken to first attend their general practitioner (GP) with symptoms. Healthcare system delays were estimated from the interval between first being assessed by their GP and starting anti-tuberculosis treatment. Median total delay was 18 weeks (0-219). The time when patients first presented to their GP was determined for 64 patients: median patient delay was then estimated as nine weeks (range 0-104 weeks), and median healthcare delay five weeks, with a very wide range (0.5-210). Prolonged delay was seen in three patients with cervical lymph node disease. Patient delay was significantly longer than healthcare system delay (p = 0.019). Pulmonary disease was associated with shorter total delay in starting treatment compared with extra-pulmonary disease (p = 0.035). In patients with tuberculosis there were considerable delays in first presentation to medical services, in diagnosis and in starting treatment. Patient delays were longer than healthcare system delays. There is a need to improve awareness of the symptoms of tuberculosis both on the part of the general population and of health professionals, especially in areas of high incidence.

Kinetics of transgene expression in mouse retina following sub-retinal injection of recombinant adeno-associated virus

Using confocal microscopy we have examined in detail the temporal and spatial pattern of green fluorescent protein expression following sub-retinal injection of recombinant adeno-associated virus (rAAV) in the mouse and have determined the effect of viral titre on the number and type of cells transduced. Our results suggest that some transgene expression occurs as early as three days after injection, and that transgene expression occurs beyond the area of retinal detachment. Vector titre appears to have a substantial effect on both transduction efficiency and the speed of onset of photoreceptor cell transduction. Our data suggests that we have not yet reached the limits of photoreceptor transduction efficiency using AAV vectors. An increase in titre could still lead to an improved transduction efficiency and faster onset of photoreceptor transduction. We failed to detect transfected cones even in areas where nearly 100% of the rods were transduced, but we found efficient and sustained RPE transduction.

Online orthodontic advice: a protocol for a pilot teledentistry system

A prototype teledentistry service was established that incorporated a PC-based expert system designed to assist in orthodontic cases. It guided the general dental practitioner (GDP) through the assessment of a patient's malocclusion and helped ensure that all relevant clinical observations were made and details recorded. The resulting data file, containing radiographic images and clinical data, was then transferred via the Internet to a dental specialist. The specialist's recommendations were returned by the same route or, where appropriate, a realtime videoconference was conducted. During an eight-month trial, six GDPs referred 158 cases through the teledentistry system; another 24 cases were referred directly to a local consultant. The protocol used during the trial worked satisfactorily. The GDPs found that it was straightforward and covered all aspects of the cases they submitted.

Dentists' opinions of an online orthodontic advice service

An online teledentistry service was tested for eight months to determine whether it could help to reduce the high level of inappropriate orthodontic referrals to consultants and provide general dental practitioners (GDPs) with quick access to advice that would enable them to tackle a wider range of cases themselves. Six GDPs took part in the trial and were interviewed after it had been running for four months. The most important conclusions from the interviews were that the process of sending cases was quite straightforward, that teledentistry was a good way of getting advice and that it was popular with both patients and their parents. The GDPs enjoyed the experience and felt that there had been significant benefits, especially in educational terms.

In vivo gene transfer to the mouse eye using an HIV-based lentiviral vector; efficient long-term transduction of corneal endothelium and retinal pigment epithelium

We have evaluated the transduction profiles of an HIV-based lentiviral vector delivered regionally to ocular tissues in vivo. Following subretinal injection, a green fluorescent protein (GFP) reporter gene was efficiently and stably expressed in retinal pigment epithelial (RPE) cells. Limited transduction of adjacent photoreceptors occurred in newborn mice, but was inefficient in adult animals. Injection of the vector into the anterior chamber resulted in efficient and stable transduction of corneal endothelial cells. Efficient in vivo gene transfer into cells of the corneal endothelium and retinal pigment epithelium by lentiviral vectors may therefore offer a valuable approach to the treatment of disorders of the cornea and outer retina.

Development of a life events/icon calendar questionnaire to ascertain occupational histories and other characteristics of migrant farmworkers

BACKGROUND

Specialized methods are necessary to collect data from migrant farmworkers for epidemiologic research.

METHODS

We developed a questionnaire that collected lifetime occupational histories and other lifestyle risk factors via a life events/icon calendar, and administered the questionnaire to a convenience sample of 162 migrant farmworkers in nine areas of the U.S.

RESULTS

The average duration of the interviews was about 1 h 30 min, with an average of 45 min for the work history section. The occupational histories covered a median of 27.6 years per person for men and 20.8 years per person for women. The median number of years spent in farm jobs was 11.3 for men and 5.8 for women. The median number of farm jobs (crop/task combination) per person was 59 among men and 27 among women. Many farmworkers performed the same crop/task combinations at multiple times throughout their lives, yielding a median of 13 unique farm jobs and 8 unique crops among men and 7 jobs and 5 crops among women.

CONCLUSIONS

The project demonstrated that it is feasible to collect detailed work histories and other risk factor data from farmworkers, documented the complexity of work histories encountered among farmworkers, and yielded recommendations for refining a questionnaire that will facilitate future epidemiologic research on farmworkers.

Gene replacement therapy in the retinal degeneration slow (rds) mouse: the effect on retinal degeneration following partial transduction of the retina

The retinal degeneration slow (rds or Prph2(Rd2/Rd2)) mouse, a model of recessive retinitis pigmentosa, lacks a functional gene encoding peripherin 2. This membrane glycoprotein is required for the formation of photoreceptor outer segment discs. The striking feature of the rds mouse is the complete failure to develop outer segments. We have previously examined the short-term effect of gene replacement therapy using an adeno-associated (AAV) vector and demonstrated induction of outer segments and improvement of photoreceptor function. Here we have extended our analysis and have demonstrated that the potential for ultrastructural improvement is dependent upon the age at which animals are treated, but the effect of a single injection on photoreceptor ultrastructure may be long-term. However, there was no significant effect on photoreceptor cell loss, irrespective of the date of administration, despite the improvements in morphology and function. Our investigation excluded procedure-related damage, vector toxicity and immune responses as major factors which might counteract the benefits of photoreceptor restoration, but suggested that transgene over-expression is of significance. These findings suggest that successful gene therapy in patients with photoreceptor defects may ultimately depend upon intervention in early stages of disease and upon accurate control of transgene expression.

Exposures and cancer incidence near oil fields in the Amazon basin of Ecuador

OBJECTIVES

To examine environmental exposure and incidence and mortality of cancer in the village of San Carlos surrounded by oil fields in the Amazon basin of Ecuador.

METHODS

Water samples of the local streams were analyzed for total petroleum hydrocarbons (TPHs). A preliminary list of potential cancer cases from 1989 to 1998 was prepared. Cases were compared with expected numbers of cancer morbidity and mortality registrations from a Quito reference population.

RESULTS

Water analysis showed severe exposure to TPHs by the residents. Ten patients with cancer were diagnosed while resident in the village of San Carlos. An overall excess for all types of cancer was found in the male population (8 observed v 3.5 expected) with a risk 2.26 times higher than expected (95% confidence interval (95% CI) 0.97 to 4.46). There was an overall excess of deaths for all types of cancer (6 v 1.6 expected) among the male population 3.6 times higher than the reference population (95% CI 1.31 to 7.81).

CONCLUSIONS

The observed excess of cancer might be associated with the pollution of the environment by toxic contaminants coming from the oil production.

[Health of women living near oil wells and oil production stations in the Amazon region of Ecuador]

OBJECTIVE

Investigate the environmental conditions in and the state of health of women who live in rural communities surrounded by oil wells and oil production stations in the Amazon region of Ecuador.

METHOD

We used a comparative cross-sectional design, classifying exposure according to the location of the communities with respect to the oil wells and production stations. Water samples from the local rivers were analyzed to determine total petroleum hydrocarbons, and a structured questionnaire was used with the head of each family in the study. The study was performed in rural communities in northeastern Ecuador from November 1998 through April 1999. The study included 9 communities in the exposed area (368 participants) and 14 communities in the unexposed area (291 participants).

RESULTS

The rivers of the exposed communities showed contamination levels much above the limits acceptable for human use. Statistically significant differences between the exposed communities and the unexposed communities were found for the prevalence of skin fungi for the two weeks prior to the study (odds ratio (OR) = 1.37; 95% confidence interval (CI) = 1.01-1.86) as well as for nasal irritation (OR = 2.18, 95% CI = 1.64-2.91) and for throat irritation (OR = 1.68, 95% CI = 1.02-2.75) in the preceding 12 months. Also associated with exposure in the two preceding weeks were fatigue and the category of "other symptoms"; similarly associated with exposure in the preceding 12 months were headaches, eye irritation, earaches, diarrhea, and gastritis.

CONCLUSIONS

The symptoms found among the participants in the exposed communities match the toxicity symptoms caused by oil. There is an urgent need to establish an adequate environmental control and remediation program in order to prevent unnecessary and unacceptable health hazards for these populations.

BCR gene expression blocks Bcr-Abl induced pathogenicity in a mouse model

It is well accepted that the Bcr-Abl oncoprotein encoded by the Philadelphia chromosome is responsible for causing chronic myelogenous leukemia (CML). We have previously demonstrated that expression of Bcr interferes with the oncogenic effects of Bcr-Abl. To examine the effects of increased Bcr expression on Bcr-Abl oncogenic effects in a more physiological system, we tested the leukemogenic potential of a clone of K562 cells (K6 K562) containing an inducible BCR gene in NOD/scid mice. In this clone, the BCR gene was placed under the control of a tetracycline (Tet) repression system with a cytomegalovirus (CMV) promoter. Induction of exogenous Bcr protein by removal of Tet from the culture medium caused a dramatic increase in Bcr serine kinase activity, yielding predominantly phosphoserine Bcr, despite the presence of Bcr-Abl in the kinase reaction mixture. Prior to induction, the endogenous Bcr was predominantly in the phosphotyrosine form because of phosphorylation by Bcr-Abl, which we previously have shown suppresses Bcr serine/threonine kinase activity. Injection of K6 K562 cells into NOD/scid mice under conditions where BCR expression was suppressed resulted in death or terminal illness in 100% of the mice within 35 days after injection. These mice had a severe wasting syndrome characterized by atrophy of bone marrow hematopoiesis, and/or neoplasia of liver, bone marrow and spleen. Neoplastic spleens from these mice usually contained b3a2 Bcr-Abl transcripts. In contrast, induction of BCR expression at the time of injection allowed 80% survival; these healthy mice had no detectable microscopic lesions in blood forming organs. This difference in survival was significant with P<0.0001. Of interest, mice that were fed Tet for 19 days to initiate the disease syndrome and then released from the BCR transcriptional block had a significantly better survival pattern than mice exposed to Tet throughout the entire period. Moreover, 30% of these mice (three mice) survived through day 50. We conclude from these findings that BCR gene expression strongly inhibits the oncogenic effects of Bcr-Abl in NOD/scid mice, yielding healthy mice in most cases.

Complete genome sequence of Caulobacter crescentus

The complete genome sequence of Caulobacter crescentus was determined to be 4,016,942 base pairs in a single circular chromosome encoding 3,767 genes. This organism, which grows in a dilute aquatic environment, coordinates the cell division cycle and multiple cell differentiation events. With the annotated genome sequence, a full description of the genetic network that controls bacterial differentiation, cell growth, and cell cycle progression is within reach. Two-component signal transduction proteins are known to play a significant role in cell cycle progression. Genome analysis revealed that the C. crescentus genome encodes a significantly higher number of these signaling proteins (105) than any bacterial genome sequenced thus far. Another regulatory mechanism involved in cell cycle progression is DNA methylation. The occurrence of the recognition sequence for an essential DNA methylating enzyme that is required for cell cycle regulation is severely limited and shows a bias to intergenic regions. The genome contains multiple clusters of genes encoding proteins essential for survival in a nutrient poor habitat. Included are those involved in chemotaxis, outer membrane channel function, degradation of aromatic ring compounds, and the breakdown of plant-derived carbon sources, in addition to many extracytoplasmic function sigma factors, providing the organism with the ability to respond to a wide range of environmental fluctuations. C. crescentus is, to our knowledge, the first free-living alpha-class proteobacterium to be sequenced and will serve as a foundation for exploring the biology of this group of bacteria, which includes the obligate endosymbiont and human pathogen Rickettsia prowazekii, the plant pathogen Agrobacterium tumefaciens, and the bovine and human pathogen Brucella abortus.

Bacterial cell cycle: seeing the big picture with microarrays

Global assays of gene expression and protein stability during the Caulobacter crescentus cell cycle reveal that a surprisingly large fraction of the genome and proteome is affected as cells grow and divide. These studies are an important step toward understanding how the cell cycle is controlled in prokaryotes.