Examination of nailfold videocapillaroscopy findings in ANCA-associated vasculitis.

OBJECTIVE: The objective of this study was to evaluate nailfold videocapillaroscopy (NVC) as a useful tool for assessing the disease activity of ANCA-associated vasculitis (AAV). METHODS: This study enrolled 51 patients with AAV and 21 healthy controls. We scored NVC findings semiquantitatively, and compared them between AAV patients and controls. We examined the association of NVC findings with disease activity indicators, histopathological findings of skin biopsies, and high-resolution CT (HRCT) scores in AAV. Additionally, we repeatedly rated the NVC findings 3 months after immunosuppressive therapy. RESULTS: Of the 51 enrolled patients, 36 (70.6%) showed a microangiopathy pattern and 4 (7.8%) showed a scleroderma pattern in AAV. The scores for microhaemorrhage, capillary loss, neoangiogenesis, and tortuosity were significantly higher in the AAV group than in the control group. NVC abnormalities correlated with the severity of skin, lung and kidney involvement. The scores of giant capillaries significantly correlated with the total BVAS and the chest BVAS; the scores of capillary loss correlated with the chest BVAS and the renal BVAS. The scores of microhaemorrhage significantly correlated with perivascular inflammatory cell infiltrations in the upper dermis of the purpura and tended to correlate with the total ground-glass opacity and consolidation scores on HRCT. In addition, capillary loss scores had a significant positive correlation with serum creatinine levels. Additionally, the microhaemorrhage scores were significantly reduced after 3 months of immunosuppressive therapy. CONCLUSION: In AAV patients, NVC abnormalities are significantly associated with disease severity. This result suggests that NVC is a useful tool for assessing the disease activity and treatment response in AAV.

Serum Complement C4 Levels Are a Useful Biomarker for Predicting End-Stage Renal Disease in Microscopic Polyangiitis.

This study aimed to evaluate the risk factors for end-stage renal disease (ESRD) in microscopic polyangiitis (MPA). In total, 74 patients with MPA were enrolled, and we compared the baseline clinical characteristics and disease activity between MPA patients who have progressed to ESRD and those without ESRD to select predictive factors for ESRD. Out of 74 patients, 12 patients (16.2%) had ESRD during follow-up. Serum C4 levels were significantly higher in MPA patients who have progressed to ESRD than in those without ESRD (p = 0.009). Multivariate analyses revealed that high serum creatinine levels (odds ratio (OR) 4.4, 95% confidence interval (CI) 1.25-15.5) and high serum C4 levels (OR 1.24, 95% CI 1.03-1.49) were risk factors for ESRD. Using receiver operating characteristic analysis, the cut-off value for initial serum C4 levels and serum creatinine levels were 29.6 mg/dL and 3.54 mg/dL, respectively. Patients with MPA with a greater number of risk factors (serum C4 levels > 29.6 mg/dL and serum creatinine levels > 3.54 mg/dL) had a higher ESRD progression rate. Serum C4 levels were significantly positively correlated with serum creatinine levels and kidney Birmingham vasculitis activity score (p = 0.02 and 0.04, respectively). These results suggest that serum C4 levels are useful tools for assessing renal disease activity and prognosis in MPA.

Prognostic Factors Affecting Death in Patients with Rheumatoid Arthritis Complicated by Pneumocystis jirovecii Pneumonia and One-Year Clinical Course: The ANSWER Cohort Study.

This multicenter retrospective study aimed to clarify the prognostic factors for mortality and changes in treatment modalities and disease activities after the onset of Pneumocystis jirovecii pneumonia (PCP) in patients with rheumatoid arthritis (RA). Data regarding the clinical background, treatment modalities, and disease activity indicators of RA at the onset of PCP (baseline), and 6 months and 12 months after treatment were extracted. Of the 37 patients with RA-PCP (median age, 69 years; 73% female), chemical prophylaxis was administered to 8.1%. Six patients died during PCP treatment. The serum C-reactive protein (CRP) levels and the prednisolone (PDN) dose at baseline in the PCP death group were significantly higher than those in the survivor group. Multivariate analysis using a Cox regression model showed that PDN dose at baseline was a predictor of death from PCP in patients with RA. During the 12 months from baseline, the RA disease activity significantly decreased. A high dose of corticosteroids for RA may result in a poor prognosis when PCP is complicated. In the future, preventive administration techniques must be established for patients with RA who need PCP prevention.

Prognostic factors affecting respiratory-related death in patients with rheumatoid arthritis complicated by interstitial lung disease: An ANSWER cohort study.

The aim of this multi-centre retrospective study was to clarify the prognostic factors for respiratory-related death in patients with interstitial lung disease (ILD) complicated rheumatoid arthritis (RA). Patient background data, treatment regimen, and disease activity indicators of RA and ILD at baseline, 6 months after the diagnosis of ILD, and at the last follow-up visit were extracted. A total of 312 patients with RA-ILD (17 patients who died from respiratory-related causes and 295 survivors) were included. Patients who died from respiratory-related causes had an older median age, a higher proportion of being male, and a higher anti-cyclic citrullinated peptide antibody positivity rate than survivors (p = .0001, .038, and .016, respectively); they also had significantly higher baseline serum levels of Krebs von den Lungen-6 (KL-6) than survivors (p = .013). Patients who died from respiratory-related causes showed significantly greater changes in serum KL-6 levels between the 6-month time point and the last visit [ΔKL-6 (6 months - last)] than survivors (p = .011). Multivariate analysis showed that the ΔKL-6 (6 months - last) corrected by disease duration was a predictor of respiratory-disease-related death in patients with RA-ILD (p < .0001). Long-term increase in serum KL-6 levels is associated with respiratory-disease related death in patients with RA-ILD.

Low pre-pregnant body mass index is a risk factor for the decrease of postpartum bone mineral density in systemic lupus erythematosus patients received glucocorticoid therapy.

OBJECTIVES: This study investigated postpartum bone mineral density (BMD) in patients with systemic lupus erythematosus (SLE) receiving long-term glucocorticoid (GC) therapy, assessed risk factors for decreased postpartum BMD, and evaluated change of BMD after postpartum initiation or restarting of osteoporosis drugs. METHODS: We retrospectively examined 30 SLE patients who gave birth and 31 non-pregnant SLE patients. In the postpartum SLE patients, BMD was measured after delivery and 1 year later. Multivariate analyses were performed to assess risk factors for decreased BMD in postpartum SLE patients. RESULTS: Patient age at pregnancy was 34.5 ± 4.5 years, and SLE duration was 9.7 ± 6.0 years. The mean prednisolone dose was 9.7 ± 3.2 mg/day. Body mass index (BMI) was 21.6 ± 2.2 kg/m2, with 13 women (43%) experiencing their first delivery. Postpartum BMD was 1.080 ± 0.120 g/cm2 in the lumbar spine and 0.834 ± 0.109 g/cm2 in the total hip. Bone loss occurred in six patients (21%) in the lumbar spine and 11 patients (37%) in the total hip. Postpartum lumbar spine BMD was significantly reduced compared to that in the non-pregnant group (1.143 ± 0.120 g/cm2, p = 0.048). Multivariate analysis identified gestational age and low BMI before pregnancy as risk factors for hip bone loss. CONCLUSION: Postpartum BMD significantly decrease in SLE patients receiving long-term GC, and low BMI before pregnancy was a risk factor for the decrease. Preconception care to prevent osteoporosis and that regularly monitors BMD after delivery are needed.

Congenital cytomegalovirus infection after maternal primary infection in a patient with systemic lupus erythematosus: A case report and literature review.

BACKGROUND: Management of infectious complications in pregnant women receiving immunosuppressive therapy for systemic lupus erythematosus (SLE) is important. Maternal infection with cytomegalovirus (CMV) often causes congenital CMV infection in the foetus. Thus far, there are only few reports on congenital CMV infection after maternal reactivation in patients with SLE. We report the first case of congenital CMV infection after maternal primary infection in a patient with SLE. CASE PRESENTATION: A 19-year-old Japanese primigravida with SLE received treatment with prednisolone 3 mg/day and azathioprine 75 mg/day at conception. At 7 weeks of gestation, she suddenly developed fever and had decreased white blood cell and platelet counts and elevated aspartate aminotransferase and alanine aminotransferase levels. These clinical findings led to a diagnosis of SLE exacerbation. The prednisolone dose was increased to 15 mg/day, and hydroxychloroquine (200 mg/day) was administered. Consequently, all clinical findings normalised at 12 weeks. At 19 weeks, foetal ultrasound findings revealed oligohydramnios, brain hypoplasia, ventriculomegaly and hyperechogenic bowel. Maternal serological test results indicated increased CMV-specific IgG and IgM levels, low IgG avidity (26%), and positive CMV antigenemia. The foetus was diagnosed with symptomatic congenital CMV infection transmitted from the maternal primary infection. After counselling about the severe prognosis of the foetus, the mother decided to terminate her pregnancy and underwent artificial abortion at 21 weeks. DISCUSSION: The foetus of a mother with SLE who is receiving immunosuppressive therapy may be at increased risk of transmission and aggravation of congenital CMV infection; thus, preventive management and screening for congenital CMV infection during pregnancy are recommended for such patients. Maternal CMV infection shows clinical findings similar to those of SLE exacerbation, and careful differential diagnosis by maternal serological evaluation and foetal ultrasound scans is required.

Comparison of therapeutic effects of combination therapy with prednisolone and tacrolimus or azathioprine on progressive interstitial pneumonia with systemic sclerosis.

OBJECTIVES: We retrospectively compared the therapeutic effects of combination therapy with prednisolone (PSL) and oral tacrolimus (TAC) or azathioprine (AZA) on progressive interstitial pneumonia with systemic sclerosis (SSc-PIP). METHODS: The effects of PSL (0.2-0.5 mg/kg/day) and TAC (3 mg/day) or AZA (1-2 mg/kg/day) therapies (n = 18) were evaluated for short (12 months) and long (36 months or more) periods. RESULTS: In the short period, IP improved in 6 and 5 patients and was stable in 12 and 13 patients in the TAC and AZA groups, respectively. In the long period, 11 patients were followed up in the TAC group and 12 in the AZA group. IP improved in 4 and 2 patients and was stable in seven and nine in the TAC and AZA groups, respectively. The rates of evolution of total fibrosis score, and those corrected by disease duration for the long period, in the TAC group were significantly lower than those in the AZA group (p = .017 and .025, respectively). CONCLUSION: The inhibitory effect of PSL and TAC combination therapy on the progression of fibrosis in SSc-PIP may be superior to that of PSL and AZA in the long period.

Simplified disease activity index and clinical disease activity index before and during pregnancy correlate with those at postpartum in patients with rheumatoid arthritis.

OBJECTIVES: We explored rheumatoid arthritis (RA) disease activity before, during, and after pregnancy in patients treated with tight control and investigated the association between disease activity in the postpartum period and those before and during pregnancy. METHODS: We retrospectively reviewed disease activity and medications of 27 patients before pregnancy, at every trimester, and in the postpartum period. RESULTS: Prednisolone was administered to 33% of patients with a median dose of 0 (0-2.5) mg/day and biologic agents was 78% in the third trimester. The median remission rates during all periods were the Disease Activity Score-28-C-reactive Protein assessed with three variables (DAS28-CRP-3) 85%, Simplified Disease Activity Index (SDAI) 55%, and Clinical Disease Activity Index (CDAI) 54%. Although SDAI and CDAI decreased significantly from before pregnancy to the first trimester and increased from the third trimester to the postpartum period, DAS28-CRP-3 did not change during all periods. Although SDAI and CDAI before and during pregnancy were significantly correlated with those in the postpartum period, DAS28-CRP-3 was not. CONCLUSIONS: Tight control before pregnancy suppressed RA disease activity during pregnancy and in the postpartum period. SDAI/CDAI before and during pregnancy were predictive for disease activity in the postpartum period.

Therapeutic drug monitoring of cyclosporine microemulsion in patients with corticosteroid-resistant systemic lupus erythematosus.

OBJECTIVES: We retrospectively examined how the cyclosporine-A (CSA) microemulsion administration mode affected blood CSA levels, as well as how the dose and blood levels of CSA affected its therapeutic effect against systemic lupus erythematosus (SLE). METHODS: We calculated the area under the blood concentration time curve (AUC) of CSA in 16 patients with corticosteroid-resistant SLE, and analyzed its correlation with CSA levels at the blood sampling time points to investigate the optimum monitoring and dosing regimen. RESULTS: The blood CSA level peaked at 2 h after administration (C2) in all patients. AUC0-6, which most markedly reflects the immunosuppressive effect, significantly correlated with C2 (R2 = 0.905), but not with the trough (C0). In concentration/dose ratio (C/D) of CSA, C2/D level was significantly higher when administered once daily before breakfast than when administered in the divided dose after meals (R2 = 0.355, P = 0.015), but not C0/D. During the 6-month follow-up, the CSA C2 tended to correlate with improvement in SLE disease activity index 2000 (R2 = 0.633, P = 0.067). CONCLUSIONS: The treatment with a single dose of CSA before breakfast, followed by monitoring of C2, may be useful for improving the therapeutic effect in patients with corticosteroid-resistant SLE.

Dermatomyositis as a complication of interferon-α therapy: a case report and review of the literature.

Autoimmune disorder is one of the important side effects of interferon-α therapy. Some polymyositis cases as complication of interferon-α therapy were reported, but dermatomyositis were rarely. We report a case of dermatomyositis as a complication of interferon-α therapy for hepatitis C. A 52-year-old Japanese man was treated by combination therapy with pegylated interferon-α-2b and ribavirin for hepatitis C. Three months after the initiation of therapy, he showed erythema in the posterior cervical to dorsal and anterior cervical to thoracic regions, weight loss, general malaise, muscle pain, and severe increase in levels of muscle enzymes. We made a diagnosis of dermatomyositis according to these clinical features, proximal muscle-predominant myogenic change on electromyography, and infiltration of monocytes and CD4+-dominant lymphocytes on skin biopsy, although myositis-associated antibodies were absent. He was successfully treated with intravenous immunoglobulin and tacrolimus in addition to glucocorticoid. This is a very rare case of dermatomyositis associated with interferon-α therapy. We reviewed several similar published cases and the association of dermatomyositis and type I interferon.

Aggressive multi-combination therapy for anti-MDA5 antibody-positive dermatomyositis-rapidly progressive interstitial lung disease.

OBJECTIVES: To elucidate the efficacy and safety of aggressive multi-combination therapy with mycophenolate mofetil, rituximab, and plasma exchange or polymyxin B immobilized fiber column direct hemoperfusion followed by conventional therapy with corticosteroids, calcineurin inhibitors, and intravenous pulse cyclophosphamide in patients with rapidly progressive interstitial lung disease (RPILD) with anti-melanoma differentiation-associated gene 5 (MDA5)-antibody-positive dermatomyositis (DM). METHODS: A total of 23 patients with anti-MDA5 antibody-positive DM-RPILD were enrolled, with nine patients in Group A (treated conventionally before March 2015) and 14 patients in Group B (received aggressive treatment after April 2015). RESULTS: Pretreatment severity of interstitial lung disease (ILD) did not differ between the two groups. However, Group B exhibited a higher cumulative survival rate at 48 weeks than Group A (64.3% vs. 33.3%). The corticosteroid dose, divided by the initial dose at 3 months and 12 months, was significantly lower in Group B than in Group A (p = .046 and .026, respectively). Among the ILD-related deaths in Group B, there was a tendency toward a higher proportion of males and more severe ILD. The incidence of infection did not differ between the groups, but leukopenia was more common in Group B. CONCLUSION: This aggressive multi-combination therapy may improve the survival outcome of patients with anti-MDA5 antibody-positive DM-RPILD. However, careful management of complications, such as opportunistic infections and leukopenia, is essential. Future refinement through longitudinal investigations tracking the long-term efficacy, safety, and cost-effectiveness of this treatment strategy is needed.

A rat retinal damage model predicts for potential clinical visual disturbances induced by Hsp90 inhibitors.

In human trials certain heat shock protein 90 (Hsp90) inhibitors, including 17-DMAG and NVP-AUY922, have caused visual disorders indicative of retinal dysfunction; others such as 17-AAG and ganetespib have not. To understand these safety profile differences we evaluated histopathological changes and exposure profiles of four Hsp90 inhibitors, with or without clinical reports of adverse ocular effects, using a rat retinal model. Retinal morphology, Hsp70 expression (a surrogate marker of Hsp90 inhibition), apoptotic induction and pharmacokinetic drug exposure analysis were examined in rats treated with the ansamycins 17-DMAG and 17-AAG, or with the second-generation compounds NVP-AUY922 and ganetespib. Both 17-DMAG and NVP-AUY922 induced strong yet restricted retinal Hsp70 up-regulation and promoted marked photoreceptor cell death 24h after the final dose. In contrast, neither 17-AAG nor ganetespib elicited photoreceptor injury. When the relationship between drug distribution and photoreceptor degeneration was examined, 17-DMAG and NVP-AUY922 showed substantial retinal accumulation, with high retina/plasma (R/P) ratios and slow elimination rates, such that 51% of 17-DMAG and 65% of NVP-AUY922 present at 30 min post-injection were retained in the retina 6h post-dose. For 17-AAG and ganetespib, retinal elimination was rapid (90% and 70% of drugs eliminated from the retina at 6h, respectively) which correlated with lower R/P ratios. These findings indicate that prolonged inhibition of Hsp90 activity in the eye results in photoreceptor cell death. Moreover, the results suggest that the retina/plasma exposure ratio and retinal elimination rate profiles of Hsp90 inhibitors, irrespective of their chemical class, may predict for ocular toxicity potential.

Synergistic activity of the Hsp90 inhibitor ganetespib with taxanes in non-small cell lung cancer models.

Systemic chemotherapy using two-drug platinum-based regimens for the treatment of advanced stage non-small cell lung cancer (NSCLC) has largely reached a plateau of effectiveness. Accordingly, efforts to improve survival and quality of life outcomes have more recently focused on the use of molecularly targeted agents, either alone or in combination with standard of care therapies such as taxanes. The molecular chaperone heat shock protein 90 (Hsp90) represents an attractive candidate for therapeutic intervention, as its inhibition results in the simultaneous blockade of multiple oncogenic signaling cascades. Ganetespib is a non-ansamycin inhibitor of Hsp90 currently under clinical evaluation in a number of human malignancies, including NSCLC. Here we show that ganetespib potentiates the cytotoxic activity of the taxanes paclitaxel and docetaxel in NSCLC models. The combination of ganetespib with paclitaxel, docetaxel or another microtubule-targeted agent vincristine resulted in synergistic antiproliferative effects in the H1975 cell line in vitro. These benefits translated to improved efficacy in H1975 xenografts in vivo, with significantly enhanced tumor growth inhibition observed in combination with paclitaxel and tumor regressions seen with docetaxel. Notably, concurrent exposure to ganetespib and docetaxel improved antitumor activity in 5 of 6 NSCLC xenograft models examined. Our data suggest that the improved therapeutic indices are likely to be mechanistically multifactorial, including loss of pro-survival signaling and direct cell cycle effects resulting from Hsp90 modulation by ganetespib. Taken together, these findings provide preclinical evidence for the use of this combination to treat patients with advanced NSCLC.

Association of M2 Macrophages, Th2, and B Cells With Pathomechanism in Microscopic Polyangiitis Complicated by Interstitial Lung Disease.

OBJECTIVE: To address the pathomechanism of microscopic polyangiitis (MPA) complicated by interstitial lung disease (ILD) using serum biomarker profile and pulmonary histopathology. METHODS: Serum biomarkers from patients with MPA-ILD (n = 32), MPA without ILD (n = 17), and healthy controls (n = 10) were examined. Based on the biomarker profiles, principal component analysis (PCA) and cluster analysis were performed to classify patients with MPA-ILD into subgroups. Clinical characteristics and prognosis were assessed for each subgroup. Two lung biopsies were examined following H&E staining and immunostaining. RESULTS: T cell and macrophage polarization was skewed toward the T helper (Th) 2 cells and M2 macrophages in the MPA-ILD group relative to that in MPA without ILD group. The PCA allowed classification of the 19 biomarker profiles into 3 groups: (1) B cell- and neutrophil-related cytokines, vascular angiogenesis-related factors, extracellular matrix-producing factors; (2) Th1-driven cytokines, M1 macrophage-driven cytokines, and Th2-driven cytokines; and (3) M2 macrophage-induced and driven cytokines. The cluster analysis stratified the patients with MPA-ILD into clinically fibrotic-dominant (CFD) and clinically inflammatory-dominant (CID) groups. Notably, severe infections were significantly higher in the CFD group than in the CID group. Immunohistochemical staining demonstrated intense CXC motif chemokine ligand 13 staining in B cells and Th2 cells in the interstitium of the lungs of patients with MPA-ILD. CONCLUSION: The activation of M2 macrophages, Th2 cells, and B cells plays a key role in the pathomechanism of MPA-ILD. Classification of MPA-ILD based on serum biomarker profile would be useful in predicting the disease activity and the complications of severe infection in MPA-ILD.

Pre-pregnancy serum complement C3 level is a predictor of preterm birth for pregnancies with systemic lupus erythematosus.

BACKGROUND: This study aimed to clarify predictors of preterm birth in pregnancy of women with systemic lupus erythematosus (SLE). We investigated the predictors of preterm birth before pregnancy from the perspective of the importance of preconception care. METHODS: We analysed fetal outcomes of 108 pregnancies in 74 SLE patients in a retrospective study. We compared pre-pregnancy clinical characteristics and disease activity in these women between the preterm birth and full-term birth groups to select predictive factors for preterm birth before pregnancy. RESULTS: Eighty-three of 108 pregnancies resulted in live births, of which 27 (25.0%) were preterm births. Pre-pregnancy serum complement 3 (C3) level was significantly lower in the preterm birth group (77.0 mg/dl) than the full-term birth group (87.5 mg/dl) (P = 0.029). Multivariate analysis identified history of lupus nephritis (odds ratio: 5.734, 95% CI 1.568-21.010, P = 0.008) and low C3 level (< 85 mg/dl) at pre-pregnancy (odds ratio 4.498, 95% CI 1.296-15.616, P = 0.018) as risk factors for preterm birth. The greater the number of these risk factors, the higher was the preterm birth rate (P = 0.0007). In the case of SLEDAI score ≤ 4, the preterm birth rate was higher in the pre-pregnancy low C3 group (< 85 mg/dl) (42.1%) than in the high C3 group (C3 ≥ 85 mg/dl) (14.7%) (P = 0.018). CONCLUSION: For patients with a history of LN, treatment management focusing on pre-pregnancy serum complement levels is very important.

Phenotypic characterization of a new Grin1 mutant mouse generated by ENU mutagenesis.

In the RIKEN large-scale N-ethyl-N-nitrosourea (ENU) mutagenesis project we screened mice with a dominant mutation that exhibited abnormal behavior in the open-field test, passive avoidance test and home-cage activity test. We tested 2045 progeny of C57BL/6J males treated with ENU and untreated DBA/2J females in the open-field test and isolated behavioral mutant M100174, which exhibited a significant increase in spontaneous locomotor activity. We identified a missense mutation in the Grin1 gene, which encodes NMDA receptor subunit 1, and designated the mutant gene Grin1(Rgsc174). This mutation results in an arginine to cysteine substitution in the C0 domain of the protein. Detailed analyses revealed that Grin1(Rgsc174) heterozygote exhibited increased novelty-seeking behavior and slight social isolation in comparison with the wild type. In contrast to other Grin1 mutant mice, this mutant exhibited no evidence of heightened anxiety. These results indicate that this is a unique behavioral Grin1 gene mutant mouse that differs from the known Grin1 mutant mice. The results of immunohistochemical and biochemical analyses suggested that impaired interaction between the glutamatergic pathway and dopaminergic pathway may underlie the behavioral phenotypes of the Grin1(Rgsc174) mutant.

A case of probable hydroxyapatite deposition disease (HADD) of the hip.

We describe a patient with acute calcific periarthritis in an unusual site, the ilio-femoral ligament. The clinical findings in this patient resembled those of septic arthritis. T2*-weighted images with gradient field echo clearly showed foci of low signal intensity in this region, corresponding to the calcification shown on plain radiographs, and increased signal intensity around the foci, representing edema. These signal intensities were diagnostic of the disease.

Potent activity of the Hsp90 inhibitor ganetespib in prostate cancer cells irrespective of androgen receptor status or variant receptor expression.

Androgen ablation therapy represents the first line of therapeutic intervention in men with advanced or recurrent prostate tumors. However, the incomplete efficacy and lack of durable response to this clinical strategy highlights an urgent need for alternative treatment options to improve patient outcomes. Targeting the molecular chaperone heat shock protein 90 (Hsp90) represents a potential avenue for therapeutic intervention as its inhibition results in the coordinate blockade of multiple oncogenic signaling pathways in cancer cells. Moreover, Hsp90 is essential for the stability and function of numerous client proteins, a number of which have been causally implicated in the pathogenesis of prostate cancer, including the androgen receptor (AR). Here, we examined the preclinical activity of ganetespib, a small molecule inhibitor of Hsp90, in a panel of prostate cancer cell lines. Ganetespib potently decreased viability in all lines, irrespective of their androgen sensitivity or receptor status, and more effectively than the ansamycin inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG). Interestingly, while ganetespib exposure decreased AR expression and activation, the constitutively active V7 truncated isoform of the receptor was unaffected by Hsp90 inhibition. Mechanistically, ganetespib exerted concomitant effects on mitogenic and survival pathways, as well as direct modulation of cell cycle regulators, to induce growth arrest and apoptosis. Further, ganetespib displayed robust antitumor efficacy in both AR-negative and positive xenografts, including those derived from the 22Rv1 prostate cancer cell line that co-expresses full-length and variant receptors. Together these data suggest that further investigation of ganetespib as a new therapeutic treatment for prostate cancer patients is warranted.

Targeting KRAS-mutant non-small cell lung cancer with the Hsp90 inhibitor ganetespib.

Mutant KRAS is a feature of more than 25% of non-small cell lung cancers (NSCLC) and represents one of the most prevalent oncogenic drivers in this disease. NSCLC tumors with oncogenic KRAS respond poorly to current therapies, necessitating the pursuit of new treatment strategies. Targeted inhibition of the molecular chaperone Hsp90 results in the coordinated blockade of multiple oncogenic signaling pathways in tumor cells and has thus emerged as an attractive avenue for therapeutic intervention in human malignancies. Here, we examined the activity of ganetespib, a small-molecule inhibitor of Hsp90 currently in clinical trials for NSCLCs in a panel of lung cancer cell lines harboring a diverse spectrum of KRAS mutations. In vitro, ganetespib was potently cytotoxic in all lines, with concomitant destabilization of KRAS signaling effectors. Combinations of low-dose ganetespib with MEK or PI3K/mTOR inhibitors resulted in superior cytotoxic activity than single agents alone in a subset of mutant KRAS cells, and the antitumor efficacy of ganetespib was potentiated by cotreatment with the PI3K/mTOR inhibitor BEZ235 in A549 xenografts in vivo. At the molecular level, ganetespib suppressed activating feedback signaling loops that occurred in response to MEK and PI3K/mTOR inhibition, although this activity was not the sole determinant of combinatorial benefit. In addition, ganetespib sensitized mutant KRAS NSCLC cells to standard-of-care chemotherapeutics of the antimitotic, topoisomerase inhibitor, and alkylating agent classes. Taken together, these data underscore the promise of ganetespib as a single-agent or combination treatment in KRAS-driven lung tumors.

Behavioral and neuromorphological characterization of a novel Tuba1 mutant mouse.

As part of the RIKEN large-scale N-ethyl-N-nitrosourea (ENU) mutagenesis project, we screened mice with a dominant mutation that exhibited abnormal behavior using an open-field test and a home-cage activity test. We tested 495 male progeny of C57BL/6J males treated with ENU and untreated C3H/HeJ females using the open-field test and isolated behavioral mutant M101736, which exhibited a significant increase in spontaneous locomotor activity. We identified a missense mutation in the Tuba1 gene, which encodes the TUBA1 protein, and designated the mutant gene Tuba1(Rgsc1736). This mutation results in an aspartic acid to glycine substitution in the TUBA1 protein. Detailed analyses revealed that Tuba1(Rgsc1736) heterozygotes exhibited inattention to novel objects and aberrant patterns of home-cage activity. The results of a behavioral pharmacological analysis using methylphenidate and morphological analyses of embryonic and adult brains suggested that Tuba1(Rgsc1736) is a novel animal model for neurodevelopmental disorders.