Real-World Experience With Deutetrabenazine for Huntington Disease Chorea

Huntington disease (HD) is a hereditary neurodegenerative disorder with a hallmark feature of chorea. While no disease-modifying therapies currently exist for HD, symptomatic treatment of HD-associated chorea includes US Food and Drug Administration-approved vesicular monoamine transporter type 2 inhibitors-tetrabenazine and deutetrabenazine. Deutetrabenazine was more recently approved (2017), and while structurally similar to tetrabenazine, deutetrabenazine has a unique pharmacokinetic profile that allows for a longer half-life, reduced plasma fluctuations, and less frequent dosing. In pivotal trials, deutetrabenazine seemed to have an improved safety and tolerability profile over tetrabenazine but real-world data to confirm this are lacking. Here, we evaluate our real-world clinical experience with deutetrabenazine for HD-associated chorea. We performed a retrospective chart review of all patients with HD who initiated treatment with deutetrabenazine from January 2017 to May 2019 at the University of Alabama at Birmingham. Total maximal chorea scores, patient-reported subjective efficacy, dosing information, and subjective reports of adverse events (AEs) were abstracted for each patient. Our review included 58 patients with a mean length of treatment of 476.4 days. In the reviewed time period, the mean treatment difference in total maximal chorea scores was 4.4. The combined total rate of occurrence of any AEs was relatively low, at 32.8%, and the most commonly reported AEs were sedation (15.5%), insomnia (6.9%), and diarrhea (3.4%). Our real-world data support current literature indicating that deutetrabenazine is an effective and well-tolerated treatment for HD-associated chorea. Further studies repeating this on a larger scale, across a greater geography and practice pattern, are needed.

High prevalence of slight and mild hearing loss across mid-life: a cross-sectional national Australian study

OBJECTIVES

Although presbycusis typically becomes symptomatic only in older age, slight and mild hearing loss may be detectable well before this. We studied current prevalence and characteristics of hearing loss in Australian mid-life adults.

STUDY DESIGN

This was a population-derived national cross-sectional study nested within the Longitudinal Study of Australian Children.

METHODS

A total of 1485 parents/guardians (87.3% female) aged 30-59 years underwent air-conduction audiometry. Hearing loss was defined in three ways to maximize cross-study comparability: high Fletcher index (mean of 1, 2 and 4 kHz; primary outcome relevant to speech perception), lower frequency (mean of 1 and 2 kHz) and higher frequency (mean of 4 and 8 kHz). Multivariable logistic regression examined how losses vary by age, sex and neighbourhood disadvantage.

RESULTS

On high Fletcher index, 27.3% had bilateral and 23.8% unilateral thresholds >15 dB hearing level (HL) (slight or worse), and 4.9% had bilateral and 6.3% unilateral thresholds >25 dB HL (mild or worse). Bilateral higher frequency losses were more common than lower frequency losses for thresholds >15 dB HL (30.9% vs. 26.4%) and >25 dB HL (11.0% vs. 4.6%). Age increased the risk of bilateral speech and higher frequency losses (all P for trend < 0.05), but not lower frequency losses >25 dB HL. Although sex was not associated with speech and lower frequency losses, men were more likely to have bilateral higher frequency losses (e.g. >15 dB HL: odds ratio [OR]: 2.2; 95% confidence interval [CI]: 1.5-3.2, P < 0.001).

CONCLUSIONS

Both slight and mild hearing loss show high and rising prevalence across mid-life. This offers opportunities to prevent progression to reduce the profound later burden of age-related hearing loss.

Safety of Converting From Tetrabenazine to Deutetrabenazine for the Treatment of Chorea

Importance

Tetrabenazine is efficacious for chorea control; however, tolerability concerns exist. Deutetrabenazine, a novel molecule that reduces chorea, was well tolerated in a double-blind, placebo-controlled study.

Objectives

To evaluate the safety and explore the efficacy of conversion from tetrabenazine to deutetrabenazine in patients with chorea associated with Huntington disease (HD).

Design, Setting, and Participants

In this ongoing, open-label, single-arm study that started on December 21, 2013, 37 patients at 13 Huntington Study Group sites in the United States and Australia who were taking stable doses of tetrabenazine that provided a therapeutic benefit were switched overnight to deutetrabenazine therapy. After week 1, the deutetrabenazine dose was titrated on a weekly basis for optimal chorea control.

Interventions

Deutetrabenazine administration at a dosage thought to provide comparable systemic exposure to the active metabolites of the prior, stable tetrabenazine regimen.

Main Outcomes and Measures

Safety measures included adverse events (AEs), clinical laboratory tests, vital signs, electrocardiograms, and validated scales. Changes in the Unified Huntington's Disease Rating Scale total maximal chorea score and total motor score were efficacy end points.

Results

Of the 53 patients with HD screened for the study, 37 ambulatory patients with manifest HD (mean [SD] age, 52.4 [11.5] years; 22 [59%] male and 15 [41%] female; 36 white [97.3%]) were enrolled. Deutetrabenazine was generally well tolerated, with low rates of neuropsychiatric AEs. Safety scales did not reveal subclinical toxicity with deutetrabenazine treatment. Rates of dose reduction or suspension attributable to AEs were also low. Chorea control, as measured by the total maximal chorea score, was maintained at week 1 and significantly improved at week 8 (mean [SD] change from baseline, 2.1 [3.2]; P < .001).

Conclusions and Relevance

In patients with chorea, overnight conversion to deutetrabenazine therapy provided a favorable safety profile and effectively maintained chorea control.

Effect of Deutetrabenazine on Chorea Among Patients With Huntington Disease: A Randomized Clinical Trial

IMPORTANCE

Deutetrabenazine is a novel molecule containing deuterium, which attenuates CYP2D6 metabolism and increases active metabolite half-lives and may therefore lead to stable systemic exposure while preserving key pharmacological activity.

OBJECTIVE

To evaluate efficacy and safety of deutetrabenazine treatment to control chorea associated with Huntington disease.

DESIGN, SETTING, AND PARTICIPANTS

Ninety ambulatory adults diagnosed with manifest Huntington disease and a baseline total maximal chorea score of 8 or higher (range, 0-28; lower score indicates less chorea) were enrolled from August 2013 to August 2014 and randomized to receive deutetrabenazine (n = 45) or placebo (n = 45) in a double-blind fashion at 34 Huntington Study Group sites.

INTERVENTIONS

Deutetrabenazine or placebo was titrated to optimal dose level over 8 weeks and maintained for 4 weeks, followed by a 1-week washout.

MAIN OUTCOMES AND MEASURES

Primary end point was the total maximal chorea score change from baseline (the average of values from the screening and day-0 visits) to maintenance therapy (the average of values from the week 9 and 12 visits) obtained by in-person visits. This study was designed to detect a 2.7-unit treatment difference in scores. The secondary end points, assessed hierarchically, were the proportion of patients who achieved treatment success on the Patient Global Impression of Change (PGIC) and on the Clinical Global Impression of Change (CGIC), the change in 36-Item Short Form- physical functioning subscale score (SF-36), and the change in the Berg Balance Test.

RESULTS

Ninety patients with Huntington disease (mean age, 53.7 years; 40 women [44.4%]) were enrolled. In the deutetrabenazine group, the mean total maximal chorea scores improved from 12.1 (95% CI, 11.2-12.9) to 7.7 (95% CI, 6.5-8.9), whereas in the placebo group, scores improved from 13.2 (95% CI, 12.2-14.3) to 11.3 (95% CI, 10.0-12.5); the mean between-group difference was -2.5 units (95% CI, -3.7 to -1.3) (P < .001). Treatment success, as measured by the PGIC, occurred in 23 patients (51%) in the deutetrabenazine group vs 9 (20%) in the placebo group (P = .002). As measured by the CGIC, treatment success occurred in 19 patients (42%) in the deutetrabenazine group vs 6 (13%) in the placebo group (P = .002). In the deutetrabenazine group, the mean SF-36 physical functioning subscale scores decreased from 47.5 (95% CI, 44.3-50.8) to 47.4 (44.3-50.5), whereas in the placebo group, scores decreased from 43.2 (95% CI, 40.2-46.3) to 39.9 (95% CI, 36.2-43.6), for a treatment benefit of 4.3 (95% CI, 0.4 to 8.3) (P = .03). There was no difference between groups (mean difference of 1.0 unit; 95% CI, -0.3 to 2.3; P = .14), for improvement in the Berg Balance Test, which improved by 2.2 units (95% CI, 1.3-3.1) in the deutetrabenazine group and by 1.3 units (95% CI, 0.4-2.2) in the placebo group. Adverse event rates were similar for deutetrabenazine and placebo, including depression, anxiety, and akathisia.

CONCLUSIONS AND RELEVANCE

Among patients with chorea associated with Huntington disease, the use of deutetrabenazine compared with placebo resulted in improved motor signs at 12 weeks. Further research is needed to assess the clinical importance of the effect size and to determine longer-term efficacy and safety.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01795859.

Identifying Motor, Emotional-Behavioral, and Cognitive Deficits that Comprise the Triad of HD Symptoms from Patient, Caregiver, and Provider Perspectives

BACKGROUND

The objective of this study was to identify important attributes associated with the triad of symptoms (cognition, emotional-behavioral, and motor) of Huntington's disease (HD) from patient, caregiver, and medical provider perspectives to facilitate development of a new disease-specific, health-related quality of life (HRQOL) instrument.

METHODS

We conducted a targeted literature review of HD and HRQOL instruments, expert surveys, and patient and caregiver phone-based interviews to extract information on the symptoms and issues most relevant to the HD symptom triad (HD triad). The data collected from these sources were used to generate themes and subdomains and to develop an integrated schema that highlights the key dimensions of the triad.

RESULTS

THE SEARCH IDENTIFIED THE FOLLOWING AREAS: emotional functioning/behavioral changes (e.g., positive emotions, sadness/depression); cognitive functioning (e.g., memory/learning, attention/comprehension); physical functioning (e.g., motor functioning, medication); social functioning (e.g., leisure, interpersonal relationships); end-of-life concerns/planning; and gene testing. Fifteen individuals diagnosed with HD and 16 HD caregivers, recruited from several Huntington's Disease Society of America support group networks, completed phone interviews. Nineteen US medical providers who specialize in HD completed the online survey. Twenty-six subdomains of the HD symptom triad (seven cognition, 12 emotional-behavioral, and seven motor) emerged relatively consistently across patient, caregiver, and provider samples. These included movements/chorea, memory impairment, depression, and anxiety.

DISCUSSION

Based on an integrated, mixed-methods approach, important HD triad symptom were identified and organized into a guiding schema. These patient-, caregiver-, and provider-triangulated data served as the basis for development of a HD-specific HRQOL instrument, the HD-PRO-TRIAD™.

HD-PRO-TRIAD™ Validation: A Patient-reported Instrument for the Symptom Triad of Huntington's Disease

Background

Few valid, disease-specific measures of health-related quality of life (HRQOL) capture the spectrum of symptoms associated with Huntington's disease (HD). The HD-PRO-TRIAD™ is a new, HD-specific, patient-reported outcome (PRO) instrument of the HD symptom triad (cognitive decline, emotional/behavioral dyscontrol, and motor dysfunction) designed for clinical research and practice. The objective was to validate the HD-PRO-TRIAD™ through a cross-sectional sample of individuals with HD and caregivers.

Methods

Development of the HD-PRO-TRIAD™ has been described elsewhere. A total of 132 individuals with HD and 40 HD caregivers, comprising 29 dyads, participated in the cross-sectional psychometric validation of this instrument. Participants provided responses to the HD-PRO-TRIAD™ and other HRQOL and disease severity instruments (EuroQOL 5D, Short Form 12, Neuro-QOL Item Banks, PROMIS Global Health, and self-reported Unified Huntington's Disease Rating Scale Total Functional Capacity and Independence Scales). Internal consistency, construct validity, and patient–caregiver proxy consistency were evaluated.

Results

Internal consistency of the three domains and overall HD-PRO-TRIAD™ instrument was supported by Cronbach's alpha values ≥0.94. Construct validity was supported by significant correlations between HD-PRO-TRIAD™ domain scores and other measures of the same domains (e.g., significant positive correlations between HD-PRO-TRIAD™ Anxiety with Neuro-QOL Anxiety), as well as slightly weaker but still strong correlations with other HRQOL instruments (e.g., HD-PRO-TRIAD™ Anxiety and UHDRS Independence; all p<0.01). Consistency between patient self-report and caregiver proxy report was supported by an intra-class correlation coefficient ≥0.92 for all three domains and the overall instrument.

Discussion

These data indicate that HD-PRO-TRIAD™ is a reliable and valid HRQOL instrument that captures the typical triad of HD symptoms.

Intraocular pressures after ketamine and sevoflurane in children with glaucoma undergoing examination under anaesthesia

AIM

For accurate intraocular pressure (IOP) measurement in very young children examination under anaesthesia (EUA) may be necessary. Most anaesthetic agents used for EUA have some effect on IOP. We compared IOPs in children after ketamine and sevoflurane anaesthesia.

METHODS

Consecutive patients with definite or suspected glaucoma, uncooperative for reliable IOP measurement in clinic and requiring EUA, were included in this study. IOPs were measured after intramuscular injection (5 mg/kg) or intravenous injection (2 mg/kg) of ketamine using a Perkins applanation tonometer. Three measurements were taken from each eye. The IOPs were rechecked after sevoflurane, given for maintenance anaesthesia. Mean IOPs were used for analysis. Paired t test was used to assess the differences in IOPs for the whole group and one-way ANOVA for the three subgroups (ketamine IOP <20, 20-30, >30 mmHg).

RESULTS

The records of eight patients (16 eyes) were available for review. The mean age was 55.42 (SD 25, range 26-89) months. Seventy data-points from both eyes (35 EUAs) were used for the analysis. The mean IOP after sevoflurane (17 (SD 10) mmHg) was statistically lower than after ketamine (24.4 (SD 12.7) mmHg, p<0.001). The percentage difference was 28.5 (SD 20.8; 95% CI 23.5 to 33.4)). The difference between the subgroups was not statistically significant (p = 0.192).

CONCLUSION

Sevoflurane lowers the IOP significantly compared with the IOP measured after ketamine. This difference is independent of the IOP level. It may be important to use ketamine as the induction anaesthetic agent when accurate IOP measurement is necessary during EUA for children.

Elevated plasma homocysteine level in patients with Parkinson disease: motor, affective, and cognitive associations

BACKGROUND

An elevated plasma homocysteine (Hcy) level has been prospectively associated with an increased risk of vascular and degenerative dementias. An Hcy elevation is prevalent in patients with Parkinson disease (PD) in part because levodopa metabolism produces Hcy. The clinical relevance of an elevated Hcy level in patients with PD is unknown.

OBJECTIVE

To determine if hyperhomocysteinemia in patients with PD is associated with depression or with cognitive or physical impairments.

DESIGN

Ninety-seven people with a mean (SD) PD duration of 3.6 (1.6) years completed the Beck Depression Inventory, a battery of 11 cognitive tests, and the motor and function components of the Unified Parkinson's Disease Rating Scale. Normalized scores for the affective, cognitive, and physical measures were compared between those with a normal Hcy level (n = 66) and those with hyperhomocysteinemia (n = 31) (Hcy level, >1.89 mg/L [>14 micro mol/L]), controlling for age, sex, disease duration, and treatment.

RESULTS

Subjects with an elevated Hcy level were slightly older (68 vs 62 years), but had similar plasma concentrations of vitamin B(12) and folate. Hyperhomocysteinemic patients were more depressed (P =.02) and had worse cognition (P<.01), but the physical measure did not differ.

CONCLUSIONS

Patients with PD and hyperhomocysteinemia are more likely to be depressed and to perform worse on neuropsychometric tasks compared with normohomocysteinemic patients. Further research is warranted to see if hyperhomocysteinemia is a reversible risk factor for neuropsychiatric burden in patients with PD.

Association of macular involvement with proliferative retinopathy in Type 2 diabetes

AIMS

To determine whether documented evidence of pre-existing maculopathy is present in Type 2 diabetic patients who require photocoagulation or vitrectomy for proliferative disease. This is a retrospective case notes review.

METHODS

The study was performed at Queen's Medical Centre, UK. All patients listed in the laser register and operating theatre register over 5 years (March 1994 to March 1999) who had undergone pan retinal photocoagulation (PRP) for diabetic retinopathy, in one consultant firm, were studied. The medical records of patients who had undergone vitrectomy as their first treatment for proliferative diabetic retinopathy in a vitreo-retinal firm over the 5 years were examined. The proportion of patients with documented maculopathy before development of proliferative retinopathy was determined.

RESULTS

All except 1/134 or 0.7% (95% confidence interval 0.1-4.5%) patients had documentation of macular signs in at least one eye prior to the patient's first session of PRP. Of the remaining 133, 104 (78%) had had focal or grid photocoagulation of the macula. The median time between the documentation of maculopathy before the first PRP treatment session was 16 months (interquartile range 7-36). Fourteen patients had vitrectomy and endolaser performed as the initial treatment for proliferative disease. All patients had documented maculopathy before the onset of proliferative disease.

CONCLUSIONS

The results of this study suggest that in Type 2 diabetes, proliferative disease occurs relatively late compared with maculopathy. In such patients, maculopathy is almost invariably present when proliferative disease is detected.

Sensitivity and specificity of a new scoring system for diabetic macular oedema detection using a confocal laser imaging system

AIM

To assess the use of the Heidelberg retina tomograph (HRT) in screening for sight threatening diabetic macular oedema in a hospital diabetic clinic, using a new subjective analysis system (SCORE).

METHODS

200 eyes of 100 consecutive diabetic patients attending a diabetologist's clinic were studied, all eyes had an acuity of 6/9 or better. All patients underwent clinical examination by an ophthalmologist. Using the HRT, one good scan was obtained for each eye centred on the fovea. A System for Classification and Ordering of Retinal Edema (SCORE) was developed using subjective assessment of the colour map and the reflectivity image. The interobserver agreement of using this method to detect macular oedema was assessed by two observers (ophthalmic trainees) who were familiarized with SCORE by studying standard pictures of eyes not in the study. All scans were graded from 0-6 and test positive cases were defined as having a SCORE value of 0-2. The sensitivity of SCORE was assessed by pooling the data with an additional 88 scans of 88 eyes in order to reduce the confidence interval of the index.

RESULTS

12 eyes in eight out of the 100 patients had macular oedema clinically. Three scans in three patients could not be analysed because of poor scan quality. In the additional group of scans 76 out of 88 eyes had macular oedema clinically. The scoring system had a specificity of 99% (95% CI 96-100) and sensitivity of 67% (95% CI 57-76). The predictive value of a negative test was 87% (95% CI 82-99), and that of a positive test was 95% (95% CI 86-99). The mean difference of the SCORE value between two observers was -0.2 (95% CI -0.5 to +0.07).

CONCLUSIONS

These data suggest that SCORE is potentially useful for detecting diabetic macular oedema in hospital diabetic patients.

1,25-Dihydroxyvitamin D3 decreases human prostate cancer cell adhesion and migration

1,25-Dihydroxyvitamin-D3 [1,25(OH)2D3], the active hormonal metabolite of vitamin D, acts through a specific nuclear receptor to inhibit proliferation and promote differentiation of several tumor cell types including the LNCaP, DU145 and PC-3 prostate cancer cell lines as well as primary prostate tumor lines. 1,25(OH)2D3 can also decrease invasion of breast and prostate cancer cell lines in vitro. We confirm this latter finding in the DU145 and PC-3 prostate cancer cell lines, and further show that 1,25(OH)2D3 inhibits overall invasion, cell adhesion and migration to the basement membrane matrix protein laminin. These changes appear to be due in part to a 1,25(OH)2D3-induced decrease in expression of alpha6 and beta4 integrins, both of which are receptors for laminin and associated with increased migration and invasion of prostate cancer cells in vitro. Blocking function of these particular integrins with antibodies inhibits both adhesion and migration of the cells. Collectively, these data demonstrate that 1,25(OH)2D3, in addition to decreasing proliferation of tumor cells, can also inhibit prostate cancer cell invasion through modulation of select cell surface adhesion molecules.

Tumor cells are the source of osteopontin and bone sialoprotein expression in human breast cancer

Bone sialoprotein (BSP) and osteopontin (OPN) are secreted glycoproteins with a conserved Arg-Gly-Asp (RGD) integrin-binding motif and are expressed predominantly in bone. The RGD tripeptide is commonly present in extracellular attachment proteins and has been shown to mediate the attachment of osteosarcoma cells and osteoclasts. To determine the origin and incidence of BSP and OPN mRNA expression in primary tumor, a cohort of archival, primary invasive breast carcinoma specimens was analyzed. BSP transcripts were detected in 65% and OPN transcripts in 77% of breast cancers examined. In general, BSP and OPN transcripts were detected in both invasive and in situ carcinoma components. The transcripts were not detected in surrounding stromal cells or in peritumoral macrophages. Despite its abundance in carcinomas, BSP expression was not detected in a panel of 11 human breast cancer cell lines (MCF-7, T47D, SK-Br-3, MDA-MB-453, MDA-MB-231, MDA-MB-436, BT549, MCF-7ADR, Hs578T, MDA-MB-435, and LCC15-MB) and OPN expression was detected only in two of these (MDA-MB-435 and LCC15-MB). To examine the possibility that expression of these genes was down-regulated in cell culture, several cell lines were grown as nude mouse xenografts in vivo; however, these tumors also failed to express BSP. OPN expression was identified in all cell lines grown as nude mouse xenografts. Our data suggest that in human primary breast tumors, the origin of BSP and OPN mRNA is predominantly the breast cancer cells and that expression of these transcripts is influenced by the tumor environment.

LCC15-MB: a vimentin-positive human breast cancer cell line from a femoral bone metastasis

The LCC15-MB cell line was established from a femoral bone metastasis that arose in a 29-year-old woman initially diagnosed with an infiltrating ductal mammary adenocarcinoma. The tumor had a relatively high (8%) S-phase fraction and 1/23 positive lymph nodes (LN). Both the primary tumor and LN metastasis were positive for estrogen receptor (ER) and progesterone receptor (PgR), but lacked erbB2 expression. Approximately one year later, the patient presented with a 0.8 cm comedo-type intraductal mammary adenocarcinoma in the left breast that was negative for ER and PgR, but positive for erbB2. Thirty-five months after the initial diagnosis she was treated for acute skeletal metastasis, and stabilized with a hip replacement. At this time, tumor cells were removed from surplus involved bone, inoculated into cell culture, and developed into the LCC 15-MB cell line. The bone metastasis was a poorly differentiated adenocarcinoma lacking ER, PgR, and erbB2, characteristics shared by the LCC15-MB cells, although ER can be re-expressed by treatment of the LCC15-MB cells for 5 days with 75 microM 5-aza-2'-deoxycytidine. The LCC15-MB cell line is tumorigenic when implanted subcutaneously in NCr nu/nu mice and produces long-bone metastases after intracardiac injection. Although the bone metastasis from which the LCC15-MB cell line was derived lacked vimentin (VIM) expression, the original primary tumor and lymph node metastasis were strongly VIM positive, as are LCC15-MB cells in vitro and in nude mice. The karyotype and isozyme profiles of LCC15-MB cells are consistent with its origin from a human female, with most chromosome counts in the hypertriploid range. Thirty-two marker chromosomes are present. These cells provide an in vitro/in vivo model in which to study the inter-relationships between ER, VIM, and bone metastasis in human breast cancer.

Bone sialoprotein supports breast cancer cell adhesion proliferation and migration through differential usage of the alpha(v)beta3 and alpha(v)beta5 integrins

Bone sialoprotein (BSP), a secreted glycoprotein found in bone matrix, has been implicated in the formation of mammary microcalcifications and osteotropic metastasis of human breast cancer (HBC). BSP possesses an integrin-binding RGD (Arg-Gly-Asp) domain, which may promote interactions between HBC cells and bone extracellular matrix. Purified BSP, recombinant human BSP fragments and BSP-derived RGD peptides are shown to elicit migratory, adhesive, and proliferative responses in the MDA-MB-231 HBC cell line. Recombinant BSP fragment analysis localized a significant component of these activities to the RGD domain of the protein, and synthetic RGD peptides with BSP flanking sequences (BSP-RGD) also conferred these responses. The fibronectin-derived RGD counterpart, GRGDSP (Gly-Arg-Gly-Asp-Ser-Pro), could not support these cellular responses, emphasizing specificity of the BSP configuration. Although most of the proliferative and adhesive responses could be attributed to RGD interactions, these interactions were only partly responsible for the migrational responses. Experiments with integrin-blocking antibodies demonstrated that BSP-RGD-induced migration utilizes the alpha(v)beta3 vitronectin receptor, whereas adhesion and proliferation responses were alpha(v)beta5-mediated. Using fluorescence activated cell sorting, we selected two separate subpopulations of MDA-MB-231 cells enriched for alpha(v)beta3 or alpha(v)beta5 respectively. Although some expression of the alternate alpha(v) integrin was still retained, the alpha(v)beta5-enriched MDA-MB-231 cells showed enhanced proliferative and adhesive responses, whereas the alpha(v)beta3-enriched subpopulation was suppressed for proliferation and adhesion, but showed enhanced migratory responses to BSP-RGD. In addition, similar analysis of two other HBC cell lines showed less marked, but similar RGD-dependent trends in adhesion and proliferation to the BSP fragments. Collectively, these data demonstrate BSP effects on proliferative, migratory, and adhesive functions in HBC cells and that the RGD-mediated component differentially employs alpha(v)beta3 and alpha(v)beta5 integrin receptors.

The LCC15-MB human breast cancer cell line expresses osteopontin and exhibits an invasive and metastatic phenotype

We have characterized the LCC15-MB cell line which was recently derived from a breast carcinoma metastasis resected from the femur of a 29-year-old woman. LCC15-MB cells are vimentin (VIM) positive, exhibit a stellate morphology in routine cell culture, and form penetrating colonies when embedded in three-dimensional gels of Matrigel or fibrillar collagen. They show high levels of activity in the Boyden chamber chemomigration and chemoinvasion assays, and like other invasive human breast cancer (HBC) cell lines, LCC15-MB cells activate matrix-metalloproteinase-2 in response to treatment with concanavalin A. In addition, these cells are tumorigenic when implanted subcutaneously in nude mice and recolonize bone after arterial injection. Interestingly, both the primary lesion and the bone metastasis from which LCC15-MB were derived, as well as the resultant cell line, abundantly express the bone matrix protein osteopontin (OPN). OPN is also expressed by the highly metastatic MDA-MB-435 cells, but not other invasive or noninvasive HBC cell lines. Expression of OPN is retained in the subcutaneous xenograft and intraosseous metastases of LCC15-MB as detected by immunohistochemistry. Both VIM and OPN expression have been associated with breast cancer invasion and metastasis, and their expression by the LCC15-MB cell line is consistent with its derivation from a highly aggressive breast cancer. These cells provide a useful model for studying molecular mechanisms important for breast cancer metastasis to bone and, in particular, the implication(s) of OPN and VIM expression in this process.

Immuno-electron microscopy reveals that the excitotoxin quinolinate is associated with the plasma membrane in human peripheral blood monocytes/macrophages

Quinolinate (QUIN), a tryptophan-derived excitotoxin, was localized ultrastructurally in human peripheral blood monocytes/macrophages (MO) by immuno-electron microscopy. A combined carbodiimide/glutaraldehyde/paraformaldehyde-based fixation procedure was developed for optimal retention of QUIN in the cell as well as minimal loss of ultrastructure; a silver-enhanced colloidal gold detection system was used for electron-microscopic analysis. Gold particles representing QUIN immunoreactivity were associated with the inner side of the plasma membrane in normal MO. The number of gold particles increased significantly when QUIN levels were elevated by treatment with its precursor kynurenine, but location of the gold particles remained essentially the same under this condition. Treatment with interferon-gamma increased the number of Golgi bodies, vacuoles and pseudopodia, reflecting the activated state of the cell. Significantly increased numbers of gold particles representing QUIN were detectable in approximately the same location as in the case of kynurenine treatment. Combined treatment with kynurenine and interferon-gamma maximally increased the number of gold particles at the periphery of the cell. The pseudopodia were intensely stained with gold particles, while they were not detectable in the inner part of the cytoplasm or in any other organelle even under this activated condition. The significance of the specific location of QUIN revealed in the present study and its relation to the release and subsequent actions of QUIN are discussed.

Human breast cancer cell metastasis to long bone and soft organs of nude mice: a quantitative assay

Bone is a common metastatic site in human breast cancer (HBC). Since bone metastasis occurs very rarely from current spontaneous or experimental metastasis models of HBC cells in nude mice, an arterial seeding model involving the direct injection of the cells into the left ventricle has been developed to better understand the mechanisms involved in this process. We present here a sensitive polymerase chain reaction (PCR) method to detect and quantitate bone and soft organ metastasis in nude mice which have been intracardially inoculated with Lac Z transduced HBC cells. Amplification of genomically incorporated Lac Z sequences in MDA-MB-231-BAG HBC cells enables us to specifically detect these cells in mouse organs and bones. We have also created a competitive template to use as an internal standard in the PCR reactions, allowing us to better quantitate levels of HBC metastasis. The results of this PCR detection method correlate well with cell culture detection from alternate long bones from the same mice, and are more sensitive than gross Lac Z staining with X-gal or routine histology. Comparable qualitative results were obtained with PCR and culture in a titration experiment in which mice were inoculated with increasing numbers of cells, but PCR is more quantifiable, less time consuming, and less expensive. This assay can be employed to study the molecular and cellular aspects of bone metastasis, and could easily be used in conjunction with RT-PCR-based analyses of gene products which may be involved with HBC metastasis.