Expression and processing of mature human frataxin after gene therapy in mice

Friedreich's ataxia is a degenerative and progressive multisystem disorder caused by mutations in the highly conserved frataxin (FXN) gene that results in FXN protein deficiency and mitochondrial dysfunction. While gene therapy approaches are promising, consistent induction of therapeutic FXN protein expression that is sub-toxic has proven challenging, and numerous therapeutic approaches are being tested in animal models. FXN (hFXN in humans, mFXN in mice) is proteolytically modified in mitochondria to produce mature FXN. However, unlike endogenous hFXN, endogenous mFXN is further processed into N-terminally truncated, extra-mitochondrial mFXN forms of unknown function. This study assessed mature exogenous hFXN expression levels in the heart and liver of C57Bl/6 mice 7-10 months after intravenous administration of a recombinant adeno-associated virus encoding hFXN (AAVrh.10hFXN) and examined the potential for hFXN truncation in mice. AAVrh.10hFXN induced dose-dependent expression of hFXN in the heart and liver. Interestingly, hFXN was processed into truncated forms, but found at lower levels than mature hFXN. However, the truncations were at different positions than mFXN. AAVrh.10hFXN induced mature hFXN expression in mouse heart and liver at levels that approximated endogenous mFXN levels. These results suggest that AAVrh.10hFXN can likely induce expression of therapeutic levels of mature hFXN in mice.

Expression and processing of mature human frataxin after gene therapy in mice

Friedreich's ataxia is a degenerative and progressive multisystem disorder caused by mutations in the highly conserved frataxin (FXN) gene that results in FXN protein deficiency and mitochondrial dysfunction. While gene therapy approaches are promising, consistent induction of therapeutic FXN protein expression that is sub-toxic has proven challenging, and numerous therapeutic approaches are being tested in animal models. FXN (hFXN in humans, mFXN in mice) is proteolytically modified in mitochondria to produce mature FXN. However, unlike endogenous hFXN, endogenous mFXN is further processed into N-terminally truncated, extra-mitochondrial mFXN forms of unknown function. This study assessed mature exogenous hFXN expression levels in the heart and liver of C57Bl/6 mice 7-10 months after intravenous administration of a recombinant adeno-associated virus encoding hFXN (AAVrh.10hFXN) and examined the potential for hFXN truncation in mice. AAVrh.10hFXN induced dose-dependent expression of hFXN in the heart and liver. Interestingly, hFXN was processed into truncated forms, but found at lower levels than mature hFXN. However, the truncations were at different positions than mFXN. AAVrh.10hFXN induced mature hFXN expression in mouse heart and liver at levels that approximated endogenous mFXN levels. These results demonstrate that AAVrh.10hFXN may induce expression of therapeutic levels of mature hFXN in mice.

Stratifying Response to Stereotactic Radiosurgery for Spinal Metastases by Primary Site Genomic Mutations

PURPOSE/OBJECTIVE(S)

Spine stereotactic radiosurgery (SSRS) is effective in achieving durable local control (LC) and palliation of pain in patients with spinal metastases. Per institutional standards, SSRS prescription dose is tailored by primary site histology, with radioresistant disease receiving escalated doses. While the association between tumor histology and radioresistance is well studied, the association between specific genotypic mutations and radioresistance to SSRS is not well known. We sought to determine if a relationship exists between primary tumor mutations and clinical outcomes following SSRS.

MATERIALS/METHODS

We performed a retrospective analysis of 201 patients with available primary site mutation profiles who underwent SSRS to 327 spinal metastases from 2007-2022 at a single institution. Associations with overall survival (OS) and LC were identified using univariate and multivariable Cox proportional hazards modeling adjusted for clinicopathologic and treatment-related factors.

RESULTS

The median age was 59 years (range: 11-85) at the time of SSRS. One hundred and five patients were male (52%). The median SSRS dose to the gross tumor volume was 24 Gy (range: 12-50) given in a median of 1 fraction (range: 1-5), corresponding to a biologically effective dose (BED10) of 81.6 Gy. The most common primary tumor sites were head and neck (20%), lung (19%), and genitourinary (15%). The most common spine subsites were thoracic (57%) and lumbar (27%). Twenty-four mutated genes were identified in primary tumors with the most common being TP53 (28%), KIT (15%), PIK3CA (15%), and KRAS (10%). Prior to receipt of SSRS, 19% of patients underwent surgical resection and 23% received conventional radiation therapy (RT) to their treated sites. The median follow-up time and OS following SSRS was 97 months (95% confidence interval [CI] 86-128) and 41 months (95% CI 20-31), respectively. The median LC at 1 and 2 years following SSRS was 88% (95% CI 84-92) and 75% (95% CI 70-82), respectively. On multivariable analysis, receipt of prior RT (hazard ratio [HR] 1.86; 95% CI 1.29-2.67; P = 0.0008) and TP53 mutation (HR 1.68; 95% CI 1.20-2.35; P = 0.0024) were associated with shorter OS, whereas STK11 mutation (HR 2.14; 95% CI 0.47-4.70; P = 0.0589) trended towards shorter OS. LC was more durable with increasing BED10 (HR 0.98; 95% CI 0.96-1.00; P = 0.0166) and less durable with mutations in ATM (HR 2.40; 95% CI 1.06-5.44; P = 0.0362), STK11 (HR 4.89; 95% CI 1.40-15.01; P = 0.0119), and CTNNB1 (HR 4.49; 95% CI 1.90-10.62; P = 0.0006).

CONCLUSION

While favorable outcomes among all patients receiving SSRS were seen, increasing BED10 was associated with more durable LC. Primary site ATM, STK11, and CTNNB1 mutations may be associated with poorer LC following SSRS. Further investigation into the prognostic value of individual mutations and combinations thereof is warranted.

Spine Stereotactic Radiosurgery for Primary and Metastatic Osteosarcoma

PURPOSE/OBJECTIVE(S)

Osteosarcoma is difficult to control due to its high propensity for metastasis and resistance to local and systemic therapies. High doses of radiation therapy (RT) may confer local control (LC) in some settings but for lesions involving the vertebral bodies, proximity to the spinal cord may limit the ability to deliver an adequate dose. In this analysis, we investigate the role of spine stereotactic radiosurgery (SSRS) to overcome this barrier and enable efficacious treatment of primary or metastatic osteosarcoma of the spine.

MATERIALS/METHODS

We retrospectively reviewed all patients treated with SSRS for osteosarcoma of the vertebrae between 2006 and 2022 at a single large tertiary cancer center. We utilized the Kaplan-Meier method to estimate overall survival (OS) and LC.

RESULTS

We identified 18 patients treated with SSRS for 25 lesions of spinal osteosarcoma. Median follow-up was 17.2 months. Two patients and three separate lesions were treated with SSRS for primary osteosarcoma of the vertebrae. The remaining 16 patients and 22 lesions received SSRS to the spine for metastatic disease. Lesions were treated to a dose of 24Gy in one fraction (n = 20) 27Gy in 3 fractions (n = 4) or 50Gy in 5 fractions (n = 1). Treatment sites included the cervical spine alone (n = 4), thoracic spine alone (n = 12), lumbar spine alone (n = 4), sacrum alone (n = 3), or both the thoracic and lumbar spine (n = 2). At latest follow up, local failure was observed in 9/25 (36%) treated lesions and median LC was 22.5 months (95% CI 6-43 months). Per-lesion LC at 1 year was 64% (95% CI 35-83%). Per-patient median OS was 14 months (95% CI 7-68 months) and OS estimates at 1 and 2 years were 60% (95% CI 32-80%) and 35% (11-60%), respectively. Among 15 patients who received 24 Gy in one fraction, at 1 year per-lesion LC was 72% (95% CI 41-88%) and per-patient OS was 60% (95% CI 28-81%). The most common acute treatment related toxicity was pain flare (12%). Four patients (16%) developed compression fractures in the treated vertebrae after radiation, with incidence between 57 and 578 days after radiation. Two of these fractures required intervention and two were incidental findings on imaging. No patients developed CTCAE Grade 3 or higher adverse events including neurological toxicities.

CONCLUSION

SSRS appears to be safe and effective in the treatment of metastatic or primary osteosarcoma involving spinal bone. Future work should include further investigation of this technique with pooled multi-institutional studies and randomized trials.

Validation of the Prognostic Index for Spine Metastasis (PRISM) Score for Stratifying Survival in Patients Treated with Spinal Stereotactic Radiosurgery

PURPOSE/OBJECTIVE(S)

Stereotactic spinal radiosurgery (SSRS) has been increasingly utilized as a first-line treatment for the management of spine metastases due to its ability to prolong survival and improve symptom control. Studies have shown that SSRS is helpful for select patients; however, there is no universal scoring system utilized to predict patient response to treatment. The Prognostic Index for Spinal Metastases (PRISM) score was shown to predict the likelihood of patients benefiting from SSRS. We sought to further demonstrate its generalizability by performing validation with a large dataset from a second high-volume institution.

MATERIALS/METHODS

We performed a retrospective review from 2017-2019 of 424 patients treated with SSRS at a single institution. Patients were stratified on the previously described PRISM criteria: Female sex (+2), solitary bone disease (+3), performance status (0 through +3.5), prior surgery at the SSRS site (+1), number of other metastatic sites (-N), prior radiation at the SSRS site (-1), and latency to treatment ≥ 5 months (+3). Patients were grouped based on PRISM scores: >7, Group 1; 4-7, Group 2; 1-3, Group 3; <1 Group 4. There were 89, 188, 88, and 59 patients in Groups 1, 2, 3, and 4, respectively. Most patients were male (70%) with a performance status of 0 (53%). The most common tumor histologies were prostate (34%), renal (18%), and lung (11%). The median biological effective dose (BED10) was 60 Gy (interquartile range [IQR], 60-82). We performed Cox proportional hazards analysis on overall survival (OS) based on PRISM score and patient and tumor characteristics. Concordance indices created from PRISM criteria and the multivariate Cox proportional analysis were compared.

RESULTS

The median follow-up time was 50.5 months (95% confidence interval [CI], 45.8-54.7) with a median overall survival of 30.3 months (95% CI, 27.3-38.4). The median overall survivals for PRISM Groups 1, 2, 3, and 4 were 57.1, 37, 23.7, and 8.8 months, respectively. There were significant differences in overall survival among PRISM groups with hazard ratios of 0.49 (95% CI, 0.35-0.69; P<0.001) for Group 1, 0.71 (95% CI, 0.55-0.91); P<0.007) for Group 2, 1,45 (95% CI, 1.08-1.94); P = 0.010) for Group 3, and 3.47 (95% CI, 2.56-4.70; P<0.001) for Group 4. Multivariable Cox analysis for patient and tumor characteristics revealed only the number of organs involved and performance status as significant clinicopathologic prognostic attributes. However, the C-index using the PRISM criteria was 0.76, which was superior to the C-index when using the significant clinicopathologic attributes by themselves (0.71).

CONCLUSION

These data demonstrate robust validation of the PRISM score to stratify OS in patients treated with SSRS and may help guide optimal treatment selection in prospective trials and clinical settings.

Enhancement Patterns of Metastatic Intrahepatic Cholangiocarcinoma and Outcomes after Chemotherapy and Radiation

PURPOSE/OBJECTIVE(S)

Patients with metastatic intrahepatic cholangiocarcinoma (M1-iCCA) have a poor prognosis with a 5-year survival rate of less than 20%. Definitive doses of radiation therapy (RT) after upfront chemotherapy (chemo/RT) in this patient population have shown to prolong survival by reducing the risk of tumor-related liver failure compared to chemotherapy alone. Our group has also identified a baseline radiographic feature, the arterial enhancement pattern, which has pathological and prognostic associations for iCCA. We tested the hypothesis that baseline arterial enhancement is independently associated with survival outcomes for patients who receive chemo/RT or chemo alone.

MATERIALS/METHODS

Patients with M1-iCCA from 2010 to 2021 were included in this retrospective study. Patients were grouped into those who underwent chemo alone and those who underwent chemo/RT. The inclusion criteria included confirmed diagnosis of M1-iCCA, availability of baseline multi-phasic computed tomography (CT), and follow-up for at least six months or until death. Tumor arterial enhancement patterns were categorized as previously described into hypovascular or hypervascular, where the tumors that were hypervascular had either peripheral enhancement or central enhancement. Mean tumor density in Hounsfield units was recorded for each patient. Survival was estimated using the Kaplan Meier method, and Cox proportional models were used to adjust for prognostic variables.

RESULTS

A total of 281 patients with iCCA were identified and 229 had evaluable CT scans. Demographic and baseline characteristics of patient groups are shown in the Table. On univariate analysis, patient age, ECOG performance status (PS) at diagnosis, treatment type, and arterial enhancement patterns associated with overall survival (OS). On multivariable analysis, the arterial enhancement pattern independently associated with OS after accounting for covariates. Patients with hypervascular tumors had prolonged OS compared to those with hypovascular tumors (HR = 0.72, [0.54 - 0.96], p = 0.02). Prolonged OS was also observed in the chemo/RT group compared to the chemo alone group (HR = 0.37, [0.25-0.54], p< 0.0001).

CONCLUSION

Baseline enhancement patterns of M1-iCCA were prognostic in the contexts of chemo alone and chemo/RT. This imaging-based biomarker may improve the ability to stratify patients for therapeutic management.

The association between low skeletal muscle mass and delirium: results from the nationwide multi-centre Italian Delirium Day 2017

Introduction

Delirium and sarcopenia are common, although underdiagnosed, geriatric syndromes. Several pathological mechanisms can link delirium and low skeletal muscle mass, but few studies have investigated their association. We aimed to investigate (1) the association between delirium and low skeletal muscle mass and (2) the possible role of calf circumference mass in finding cases with delirium.

Methods

The analyses were conducted employing the cross-sectional “Delirium Day” initiative, on patient 65 years and older admitted to acute hospital medical wards, emergency departments, rehabilitation wards, nursing homes and hospices in Italy in 2017. Delirium was diagnosed as a 4 + score at the 4-AT scale. Low skeletal muscle mass was operationally defined as calf circumference ≤ 34 cm in males and ≤ 33 cm in females. Logistic regression models were used to investigate the association between low skeletal muscle mass and delirium. The discriminative ability of calf circumference was evaluated using non-parametric ROC analyses.

Results

A sample of 1675 patients was analyzed. In total, 73.6% of participants had low skeletal muscle mass and 24.1% exhibited delirium. Low skeletal muscle mass and delirium showed an independent association (OR: 1.50; 95% CI 1.09–2.08). In the subsample of patients without a diagnosis of dementia, the inclusion of calf circumference in a model based on age and sex significantly improved its discriminative accuracy [area under the curve (AUC) 0.69 vs 0.57, p < 0.001].

Discussion and conclusion

Low muscle mass is independently associated with delirium. In patients without a previous diagnosis of dementia, calf circumference may help to better identify those who develop delirium.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40520-021-01950-8.

Dose escalation of definitive radiation is not associated with improved survival for cervical esophageal cancer: a National Cancer Data Base (NCDB) analysis

For cervical esophageal cancer (CEC), National Comprehensive Cancer Network guidelines support RT to 50-50.4 Gy with chemotherapy but acknowledge higher doses may be appropriate. This study uses the National Cancer Database (NCDB) to characterize RT practices and identify if a dose-response relationship exists for overall survival (OS) for definitive treatment of CEC. We queried the NCDB for patients diagnosed with Stage I-III CEC from 2004 to 2013, and selected patients receiving definitive RT with doses between 50 and 74 Gy. Using multivariate logistic regression, the database was analyzed to determine factors associated with use of RT > 50.4 Gy. Patients were then stratified into three dose categories. Predictors of OS were analyzed with univariate and multivariate methods using the Kaplan-Meier curves, the log-rank test, and the Cox proportional hazards analysis. We stratified 789 patients with CEC who were treated with definitive radiation ± chemotherapy: 50-50.4 Gy ('standard'), >50.4 and <66 Gy ('medium'), and 66-74 Gy ('high'). Of these patients, 215 (27%) received standard doses, 375 (48%) received medium doses, and 199 (25%) received high doses. Patients with Medicaid insurance and those with Stage II disease were less likely (P < 0.05) to receive >50.4 Gy. Sex, histology, distance to treatment facility, and academic/community facility type were not significantly associated with receipt of >50.4 Gy. There was no association between dose and OS for the medium or high groups when using univariate analysis or analysis adjusted for demographic, facility, and clinical attributes. Stage III disease and the Charlson-Deyo scores of 1 or 2 were associated with higher mortality (P < 0.05), while female sex and use of chemotherapy were associated with lower mortality (P < 0.01). Nearly three-fourths of CEC patients in the United States are treated with RT > 50.4 Gy. Higher radiation doses were not associated with increased OS in CEC patients in the NCDB.

Reproductive activities of Heliotropium indicum isolate against Helopeltis theivora and toxicity evaluation in mice

A new compound E was isolated from the methanolic extract of the leaves of Heliotropium indicum by chromatographic fractionation. In the present study, the effect of the compound E on reproduction of Helopeltis theivora has been evaluated. The acute toxicity study (LD50) and sub-acute toxicity studies (haematological, biochemical and histopathological parameters) in albino Swiss mice were carried out to evaluate the safety aspect of the compound E. The compound showed significant inhibitory effect on the reproductive life of H. theivora. The oviposition period, fecundity and hatching percentage of H. theivora were found to be 15.67 days, 39.33 and 28.00% respectively after treatment with 2% compound E, whereas the control value were found to be 20.33 days, 77.67 and 77.33% respectively. The LD50 of the compound was found to be 780 mg kg(-1) in Swiss albino female mice. The compound did not show any toxicity in mice at sub-lethal dose treatment (78 mg kg(-1) b. wt., once daily) for 21 days as evident from different haematological, biochemical and histopathological parameters in compound E treated group when compared with control.

Genetic delivery of an anti-RSV antibody to protect against pulmonary infection with RSV

Respiratory syncytial virus (RSV) is a common cause of severe lower respiratory tract infections. Protection against infection with RSV can be achieved by monthly administration of the humanized monoclonal antibody palivizumab. The present study analyzes if genetic delivery of a murine version of palivizumab by single administration would achieve high-level and sustained antibody expression to protect mice against pulmonary infection with RSV. A murine version of the palivizumab antibody was constructed by replacing the human sequences with sequences from the constant region of a murine IgG1 antibody, while preserving the complementarity-determining region. As a proof-of-principle to test the validity of the strategy, the coding sequence for the heavy and light chains were cloned into a replication-defective serotype 5 human adenovirus vector (AdalphaRSV). Antibody expression and specificity for RSV was confirmed by Western analysis. To determine if AdalphaRSV would mediate production of anti-RSV antibodies in vivo, 5x10(10) particle units of AdalphaRSV or a control vector without transgene (AdNull), were administered intravenously to BALB/c mice. RSV neutralizing antibodies were detected in the serum after 4 days in mice receiving AdalphaRSV but not in AdNull-infected or naive mice (p<0.05). The mice that had received AdalphaRSV had at least 5.4-fold lower RSV titers in the lung 4 days following intranasal challenge with RSV compared to the AdNull or naive group (p<0.01). To evaluate long-term protection, the antibody construct was expressed in a non-human primate serotype rh.10 adeno-associated virus vector (AAVrh.10alphaRSV). RSV neutralizing antibodies were detected in serum and bronchoalveolar lavage fluid for up to 21 wk following intrapleural administration of AAVrh.10alphaRSV, but not with a control AAV vector expressing an unrelated transgene (AAVrh.10alpha1AT). Following challenge with RSV at 7 or 21 wk, 14.3-fold and 10.6-fold lower RSV titers were observed after 4 days in the lungs of mice that had received AAVrh.10alphaRSV compared to AAVrh.10alpha1AT (p<0.05). Together these data demonstrate that a gene transfer strategy for delivery of an anti-RSV antibody can generate protective immunity in mice against RSV infection in the respiratory tract and may provide an alternative to the administration of the antibody itself.

AAV2-mediated CLN2 gene transfer to rodent and non-human primate brain results in long-term TPP-I expression compatible with therapy for LINCL

Late infantile neuronal ceroid lipofuscinosis (LINCL) is a fatal, autosomal recessive disease resulting from mutations in the CLN2 gene with consequent deficiency in its product tripeptidyl peptidase I (TPP-I). In the central nervous system (CNS), the deficiency of TPP-I results in the accumulation of proteins in lysosomes leading to a loss of neurons causing progressive neurological decline, and death by ages 10-12 years. To establish the feasibility of treating the CNS manifestations of LINCL by gene transfer, an adeno-associated virus 2 (AAV2) vector encoding the human CLN2 cDNA (AAV2CUhCLN2) was assessed for its ability to establish therapeutic levels of TPP-I in the brain. In vitro studies demonstrated that AAV2CUhCLN2 expressed CLN2 and produced biologically active TPP-I protein of which a fraction was secreted as the pro-TPP-I precursor and was taken up by nontransduced cells (ie, cross-correction). Following AAV2-mediated CLN2 delivery to the rat striatum, enzymatically active TPP-I protein was detected. By immunohistochemistry TPP-I protein was detected in striatal neurons (encompassing nearly half of the target structure) for up to 18 months. At the longer time points following striatal administration, TPP-I-positive cell bodies were also observed in the substantia nigra, frontal cerebral cortex and thalamus of the injected hemisphere, and the frontal cerebral cortex of the noninjected hemisphere. These areas of the brain contain neurons that extend axons into the striatum, suggesting that CNS circuitry may aid the distribution of the gene product. To assess the feasibility of human CNS delivery, a total of 3.6 x 10(11) particle units of AAV2CUhCLN2 was administered to the CNS of African green monkeys in 12 distributed doses. Assessment at 5 and 13 weeks demonstrated widespread detection of TPP-I in neurons, but not glial cells, at all regions of injection. The distribution of TPP-I-positive cells was similar between the two time points at all injection sites. Together, these data support the development of direct CNS gene transfer using an AAV2 vector expressing the CLN2 cDNA for the CNS manifestations of LINCL.

Comparison of the pharmacology of hydroxamate- and carboxylate-based matrix metalloproteinase inhibitors (MMPIs) for the treatment of osteoarthritis

OBJECTIVE AND DESIGN

Hydroxamic-and carboxylic-acid based matrix metalloproteinase inhibitors (MMPIs) were compared for their potency against various MMPs, pharmacodynamic properties and in vivo efficacy in a model of cartilage degeneration.

MATERIALS AND METHODS

The MMPIs were evaluated for their ability to inhibit human MMPs using the quenched fluorescence assay. The ability of the MMPIs to inhibit the degeneration of the knee joint was evaluated in rats injected intraarticularly with iodoacetate. The amount of MMPI in the plasma and cartilage was determined using liquid chromatography/mass spectrometry/mass spectrometry (LC/ MS/MS). Plasma protein binding was measured by ultrafiltration and unbound MMPI was quantitated using HPLC.

RESULTS

The hydroxamic acid based inhibitor PGE-3321996 and the carboxylic acids PGE-2909492 and PGE-6292544 were potent MMP-13 inhibitors, but only the hydroxamic acid PGE 3321996 demonstrated significant inhibition of knee degeneration in the rat iodoacetate model. Both of the carboxylic acids demonstrated superior pharmacokinetic properties and established much higher plasma concentrations than the hydroxamic acid. However, neither of the carboxylic acids was detectable in the cartilage, whereas, the hydroxamic acid was present in both the cartilage and the plasma. The carboxylic acid based MMPIs also demonstrated higher plasma protein binding (>99%) than the hydroxamic acid (79%).

CONCLUSIONS

Carboxylic acid-based MMPIs were identified that had superior in vivo plasma exposure compared to a hydroxamic acid inhibitor but lacked in vivo efficacy in the rat iodoacetate model of cartilage degeneration. The lack of in vivo efficacy of the carboxylic acid based MMPIs were probably due to their lack of cartilage penetration which was related to their physicochemical properties.

Intrapleural administration of a serotype 5 adeno-associated virus coding for α1-antitrypsin mediates persistent, high lung and serum levels of α1-antitrypsin

alpha1-Antitrypsin (alpha1AT) is a serine proteinase inhibitor that protects the lung from degradation by neutrophil proteases. In alpha1AT deficiency, an autosomal recessive disorder resulting from mutations in the alpha1AT (approved symbol SERPINA1) gene, serum alpha1AT levels of < 570 microg/ml are associated with development of emphysema. Adeno-associated virus (AAV) serotype 2 (AAV2) vectors expressing alpha1AT administered intramuscularly or intravenously mediate sustained serum levels of alpha1AT in experimental animals. Since the lung is only 2% of the body weight, AAV vector delivery to the muscle or liver is inefficient, as most of the alpha1AT does not reach the lung. The present study evaluates AAV2- and AAV5-mediated delivery of human alpha1AT (halpha1AT) to C57BL/6 mice using the intrapleural space as a platform for local production of alpha1AT. Intrapleural administration of either an AAV5-halpha1AT or an AAV2-halpha1AT vector achieves higher lung and serum levels of alpha1AT than intramuscular delivery. AAV5-mediated serum and lung alpha1AT levels were 10-fold higher than those achieved by AAV2 delivery via either route. The diaphragm, lung, and heart are the major sites of transgene expression following intrapleural administration of an AAV5 reporter vector. At 40 weeks postadministration, intrapleural administration of the AAV5-halpha1AT vector mediated serum alpha1AT levels of 900 +/- 50 microg/ml, 1.6-fold higher than the accepted therapeutic level of 570 microg/ml. In the context that the pleura is a safe site for administration, intrapleural administration using AAV5 vectors may represent an attractive gene therapy strategy for alpha1AT deficiency in humans.

Synthesis and biological evaluation of prostaglandin-F alkylphosphinic acid derivatives as bone anabolic agents for the treatment of osteoporosis

A series of novel C(1) alkylphosphinic acid analogues of the prostaglandin-F family have been evaluated at the eight human prostaglandin receptors for potential use in the treatment of osteoporosis. Using molecular modeling as a tool for structure-based drug design, we have discovered that the phosphinic acid moiety (P(O)(OH)R) behaves as an isostere for the C(1) carboxylic acid in the human prostaglandin FP binding assay in vitro and possesses enhanced hFP receptor selectivity when compared to the parent carboxylic acid. When evaluated in vivo, the methyl phosphinic acid analogue (4b) produced a bone anabolic response in rats, returning bone mineral volume (BMV) [corrected], to intact levels in the distal femur in the ovariectomized rat (OVX) model. These results suggest that prostaglandins of this class may be useful agents in the treatment of diseases associated with bone loss.

Moderation of iodoacetate-induced experimental osteoarthritis in rats by matrix metalloproteinase inhibitors

OBJECTIVE

To determine the effect of matrix metalloproteinase (MMP) inhibitors in mono-iodoacetate-induced arthritis in rats.

DESIGN

The ability of compounds to inhibit MMPs in vitro was assessed kinetically using a quenched fluorescent substrate. Rats were injected with iodoacetate intraarticularly in one knee joint and damage to the tibial plateau was evaluated from digitized images captured using an image analyser and by histology. Collagenase and gelatinase activity in cartilage from iodoacetate injected knees were evaluated using(3)H-rat type I collagen and gelatin zymography, respectively.

RESULTS

Collagenase and gelatinase activity significantly increased in the knee cartilage of rats injected with iodoacetate with peak activity by day 7. Three MMP inhibitors were examined for their efficacy in the rat iodoacetate-induced arthritis model. Significant (P< 0.05) inhibition of cartilage damage was observed in animals treated orally with 35 mg/kg b.i.d. of the three different MMP inhibitors. Inhibition of cartilage damage by the MMP inhibitors ranged from 36-42%.

CONCLUSION

MMP inhibitors are partially protective against cartilage and subchondral bone damage induced by iodoacetate. These results support an important role for MMPs in mediating the joint damage in this model of arthritis.

The development of new carboxylic acid-based MMP inhibitors derived from a cyclohexylglycine scaffold

A series of carboxylic acids was prepared based on cyclohexylglycine scaffolds and tested for potency as matrix metalloproteinase (MMP) inhibitors. Detailed SAR for the series is reported for five enzymes within the MMP family, and a number of inhibitors such as compound 18 display low nanomolar potency for MMP-2 and MMP-13, while selectively sparing MMP-1 and MMP-7.

Heterocycle-based MMP inhibitors with P2' substituents

Potent and selective inhibition of matrix metalloproteinases was demonstrated for a series of sulfonamide-based hydroxamic acids. The design of the heterocyclic sulfonamides incorporates a six- or seven-member central ring with a P2' substituent that can be modified. Binding interactions of this substituent at the S2' site are believed to contribute to high inhibitory potency against stromelysin, collagenase-3 and gelatinases A and B, and to provide selectivity against collagenase-1 and matrilysin. An X-ray structure of a stromelysin inhibitor complex was obtained to provide insights into the SAR and selectivity trends observed for the series.

Development of new carboxylic acid-based MMP inhibitors derived from functionalized propargylglycines

A series of carboxylic acids were prepared from a propargylglycine scaffold and tested for efficacy as matrix metalloproteinase (MMP) inhibitors. Detailed SAR for the series is reported for four enzymes within the MMP family. The inhibitors were typically potent against collagenase-3 (MMP-13) and gelatinase A (MMP-2), while they spared collagenase-1 (MMP-1) and only moderately inhibited stromelysin (MMP-3). Compound 40 represents a typical inhibition profile of a compound with reasonable potency. Introduction of polar groups was required in order to generate inhibitors with acceptable water solubility, and this often resulted in a loss of potency as in compound 63. High serum protein binding proved to be a difficult hurdle with many compounds such as 48 showing >99% binding. Some compounds such as 64 displayed approximately 90% binding, but no reliable method was discovered for designing molecules with low protein binding. Finally, selected data regarding the pharmacokinetic behavior of these compounds is presented.

An efficient synthesis of 3-hetero-13,14-dihydro prostaglandin F1alpha analogues

[structure: see text]. A new class of 3-hetero-13,14-dihydro prostaglandin F(1)(alpha) analogues was synthesized from a common intermediate. The latter was constructed via a two-step, three-component process. The lower chain, containing the 15-(phenoxymethyl) group, was synthesized in enantiopure form using Jacobsen's (salen)Co-catalyzed kinetic resolution of a terminal epoxide with phenol.

Development of new hydroxamate matrix metalloproteinase inhibitors derived from functionalized 4-aminoprolines

A series of hydroxamates was prepared from an aminoproline scaffold and tested for efficacy as matrix metalloproteinase (MMP) inhibitors. Detailed SAR for the series is reported for five enzymes within the MMP family, and a number of inhibitors, such as compound 47, display broad-spectrum activity with sub-nanomolar potency for some enzymes. Modifications of the P1' portion of the molecule played a key role in affecting both potency and selectivity within the MMP family. Longer-chain aliphatic substituents in this region of the molecule tended to increase potency for MMP-3 and decrease potency for MMP-1, as exemplified by compounds 48-50, while aromatic substituents, as in compound 52, generated broad-spectrum inhibition. The data is rationalized based upon X-ray crystal data which is also presented. While the in vitro peroral absorption seemed to be less predictable, it tended to decrease with longer and more hydrophilic substituents. Finally, a rat model of osteoarthritis was used to evaluate the efficacy of these compounds, and a direct link was established between their pharmacokinetics and their in vivo efficacy.

The synthesis and human FP receptor binding affinity of 13,14-dihydro prostaglandin F1alpha sulfonamides: potential treatments for osteoporosis

A novel class of saturated prostaglandin F2alpha sulfonamide analogs have been synthesized and evaluated in the human FP receptor binding assay for potential use in the treatment of osteoporosis. These compounds have been modified at the C1 carboxylic acid moiety and at the C16-C20 region of the prostaglandin. Based on the structure-activity relationships, it was found that at C1, the aryl sulfonamide analogs possessed greater affinity for the hFP receptor when compared to alkyl sulfonamides. When the sulfonamide was introduced into the C16-C20 region (omega chain) of the prostaglandin, a significant reduction in binding was observed. These results are discussed within the framework of a proposed model for the human FP receptor.

Design and synthesis of 13,14-dihydro prostaglandin F(1alpha) analogues as potent and selective ligands for the human FP receptor

The in vitro evaluation of a new class of potential bone anabolic agents for the treatment of osteoporosis is described. These compounds are potent and selective ligands for the human prostaglandin F receptor (hFP receptor). The compounds lack the olefin unsaturation required for potency in the natural ligand PGF(2)(alpha) yet retain binding affinity for the hFP receptor in the nanomolar to micromolar range. Removal of the alkenes also results in a better selectivity ratio for the hFP receptor over the other prostaglandin receptors tested. A rationale for the selectivity differences of various analogues, based on ligand docking experiments to a putative hFP receptor model, is also described.

Design and synthesis of piperazine-based matrix metalloproteinase inhibitors

A new generation of cyclic matrix metalloproteinase (MMP) inhibitors derived from dl-piperazinecarboxylic acid has been described. The design involves: incorporation of hydroxamic acid as the bidentate chelating agent for catalytic Zn(2+), placement of a sulfonamide group at the 1N-position of the piperazine ring to fill the S1' pocket of the enzyme, and finally attachment of diverse functional groups at the 4N-position to optimize potency and peroral absorption. A unique combination of all three elements produced inhibitor 20 with high affinity for MMPs 1, 3, 9, and 13 (24, 18, 1.9, and 1.3 nM, respectively). X-ray crystallography data obtained for MMP-3 cocrystallized with 20 gave detailed information on key binding interactions defining an overall scaffold geometry for piperazine-based MMP inhibitors.

Design, synthesis, and biological evaluation of matrix metalloproteinase inhibitors derived from a modified proline scaffold

The synthesis and structure-activity relationship (SAR) studies of a series of proline-based matrix metalloproteinase inhibitors are described. The data reveal a remarkable potency enhancement in those compounds that contain an sp(2) center at the C-4 carbon of the ring relative to similar, saturated compounds. This effect was noted in compounds that contained a functionalized oxime moiety or an exomethylene at C-4, and the potencies were typically <10 nM for MMP-3 and <100 nM for MMP-1. Comparisons were then made against compounds with similar functionality where the C-4 carbon was reduced to sp(3) hybridization and the effect was typically an order of magnitude loss in potency. A comparison of compounds 14 and 34 exemplifies this observation. An X-ray structure was obtained for a stromelysin-inhibitor complex which provided insights into the SAR and selectivity trends observed within the series. In vitro intestinal permeability data for many compounds was also accumulated.

Design, synthesis, and biological evaluation of potent thiazine- and thiazepine-based matrix metalloproteinase inhibitors

The synthesis and enzyme inhibition data for a series of thiazine- and thiazepine-based matrix metalloproteinase (MMP) inhibitors are described. The thiazine- and thiazepine-based inhibitors were discovered by optimization of hetererocyclic sulfonamide-based inhibitors. The most potent series of inhibitors was obtained by modification of the amino acid D-penicillamine. This amino acid provides a gem-dimethyl group on the thiazine or thiazepine ring which has a dramatic effect on the in vitro potency of this series. In particular, the sulfide 4a and the sulfone 5a were potent, broad-spectrum inhibitors of the MMPs with IC(50)'s against MMP-1 of 0.8 and 1.9 nM, respectively. The binding mode of this novel thiazepine-based series of MMP inhibitors was established based on X-ray crystallography of the complex of stromelysin and 4a.