A Pragmatic, Randomized Controlled Trial of Oral Antivirals for the Treatment of Chronic Hepatitis C: The PRIORITIZE Study.

BACKGROUND AND AIMS: Multiple direct-acting antiviral (DAA) regimens are available to treat HCV genotype 1 infection. However, comparative effectiveness from randomized controlled trials of DAA regimens is unavailable. APPROACH AND RESULTS: We conducted a pragmatic randomized controlled trial (NCT02786537) to compare the effectiveness of DAAs for HCV genotype 1a or 1b on viral response, safety, tolerability, and medication nonadherence. Adults with compensated liver disease, HCV genotype 1, not pregnant or breastfeeding, and with health insurance likely to cover ledipasvir/sofosbuvir (LDV/SOF) were recruited from 34 US viral hepatitis clinics. Participants were randomized (± ribavirin) to LDV/SOF, elbasvir/grazoprevir (EBR/GZR), and paritaprevir/ritonavir/ombitasvir+dasabuvir (PrOD; treatment arm stopped early). Primary outcomes included sustained viral response at 12 weeks (SVR12), clinician-recorded adverse events, patient-reported symptoms, and medication nonadherence. Between June 2016 and March 2018, 1,609 participants were randomized. Among 1,128 participants who received ≥1 dose of EBR/GZR or LDV/SOF (± ribavirin), SVR12 was 95.2% (95% CI, 92.8%-97.6%) and 97.4% (95% CI, 95.5%-99.2%), respectively, with a difference estimate of 2.2% (-0.5% to 4.7%), falling within the "equivalence" interval (-5% to 5%). While most (56%) participants experienced adverse events, few were serious (4.2%) or severe (1.8%). In the absence of ribavirin, discontinuations due to adverse events were rare. Patient-reported symptoms and medication nonadherence were similar. Study limitations were dropout due to insurance denial and loss to follow-up after treatment, limiting the ability to measure SVR12. CONCLUSIONS: This pragmatic trial demonstrated high SVR12 for participants treated with EBR/GZR and LDV/SOF with few adverse effects. Overall, the two regimens were equivalent in effectiveness. The results support current HCV guidelines that do not distinguish between ribavirin-free EBR/GZR and LDV/SOF.

Successful treatment by on-demand glecaprevir and pibrentasvir for hepatitis C flare during R-CHOP in patients with diffuse large B-cell lymphoma: a case report.

BACKGROUND: In patients with hepatitis C virus (HCV) and malignant lymphoma, hepatitis C flare during R-CHOP can result in discontinuation of treatment. However, appropriate therapeutic strategies for managing hepatitis C flare during R-CHOP have not been established, and this issue is complicated by conflicting results regarding the use of direct-acting antivirals in patients with uncontrolled malignancies. CASE PRESENTATION: We report the first case of effective and safe treatment with on-demand 8-week glecaprevir and pibrentasvir for hepatitis C flare during R-CHOP in a patient with diffuse large B-cell lymphoma (DLBCL). The patient completed five additional courses of R-CHOP without hepatic toxicity. A complete response of DLBCL and a sustained virological response were observed at 24 weeks after glecaprevir and pibrentasvir completion. CONCLUSION: On-demand, direct-acting antivirals could be a novel strategy for managing hepatitis C flare during R-CHOP.

Effects of 17-AAG on the RIP1/RIP3/MLKL pathway during the development of heart failure following myocardial infarction in rats.

In a previous study, we suggested that the Hsp90 inhibitor 17-AAG prevents cardiac dysfunction in the failing heart following myocardial infarction in rats. Although it is assumed that the RIP1/RIP3/MLKL necroptotic pathway, which comprises client proteins for Hsp90, is involved; however, the relationship between the cardioprotective effects of 17-AAG and the activity of the cardiac RIP1/RIP3/MLKL necrosome-associated proteins in the failing heart following myocardial infarction remained unclear. Therefore, the levels of phosphorylated MLKL after myocardial infarction with or without Hsp90 inhibitor treatment were measured. Myocardial infarction was induced by ligation of the coronary artery (CAL) in Wistar rats. 17-AAG was injected from the 2nd to the 8th week after myocardial infarction. The administration of 17-AAG attenuated the cardiac dysfunction, hypertrophy, and fibrosis at the 8th week after CAL, simultaneously lessening the increases in the expression and phosphorylation levels of RIP1, RIP3, and MLKL in the area of the left ventricular muscle without infarct. These results indicate that the activation of the RIP1/RIP3/MLKL pathway is a common event in the development of chronic heart failure. Furthermore, our findings suggest that the effects of 17-AAG treatment on the improvement of cardiac function in rats after myocardial infarction is related to the attenuation of this RIP1/RIP3/MLKL pathway.

Berberine regulates the Notch1/PTEN/PI3K/AKT/mTOR pathway and acts synergistically with 17-AAG and SAHA in SW480 colon cancer cells.

CONTEXT: Berberine (BBR) is used to treat diarrhoea and gastroenteritis in the clinic. It was found to have anticolon cancer effects. OBJECTIVE: To study the anticolon cancer mechanism of BBR by connectivity map (CMAP) analysis. MATERIALS AND METHODS: CMAP based mechanistic prediction was conducted by comparing gene expression profiles of 10 µM BBR treated MCF-7 cells with that of clinical drugs such as helveticoside, ianatoside C, pyrvinium, gossypol and trifluoperazine. The treatment time was 12 h and two biological replications were performed. The DMSO-treated cells were selected as a control. The interaction between 100 µM BBR and target protein was measured by cellular thermal shift assay. The protein expression of 1-9 µM BBR treated SW480 cells were measured by WB assay. Apoptosis, cell cycle arrest, mitochondrial membrane potential (MMP) of 1-9 µM BBR treated SW480 cells were measured by flow cytometry and Hoechst 33342 staining methods. RESULTS: CMAP analysis found 14 Hsp90, HDAC, PI3K or mTOR protein inhibitors have similar functions with BBR. The experiments showed that BBR inhibited SW480 cells proliferation with IC50 of 3.436 µM, induced apoptosis, autophage, MMP depolarization and arrested G1 phase of cell cycle at 1.0 µM. BBR dose-dependently up-regulated PTEN, while inhibited Notch1, PI3K, Akt and mTOR proteins at 1.0-9.0 µM (p < 0.05). BBR also acted synergistically with Hsp90 and HDAC inhibitor (0.01 µM) in SW480 cells at 0.5 and 1.0 µM. DISCUSSION AND CONCLUSIONS: The integrative gene expression-based chemical genomic method using CMAP analysis may be applicable for mechanistic studies of other multi-targets drugs.

Lorlatinib in previously treated anaplastic lymphoma kinase-rearranged non-small cell lung cancer: Japanese subgroup analysis of a global study.

Lorlatinib is a potent, brain-penetrant, third-generation anaplastic lymphoma kinase (ALK)/ROS proto-oncogene 1 (ROS1) tyrosine kinase inhibitor (TKI) that is active against most known resistance mutations. This is an ongoing phase 1/2, multinational study (NCT01970865) investigating the efficacy, safety and pharmacokinetics of lorlatinib in ALK-rearranged/ROS1-rearranged advanced non-small cell lung cancer (NSCLC) with or without intracranial (IC) metastases. Because patterns of ALK TKI use in Japan differ from other regions, we present a subgroup analysis of Japanese patients. Patients were enrolled into six expansion (EXP) cohorts based on ALK/ROS1 mutation status and treatment history. The primary endpoint was the objective response rate (ORR) and the IC-ORR based on independent central review. Secondary endpoints included pharmacokinetic evaluations. At data cutoff, 39 ALK-rearranged/ROS1-rearranged Japanese patients were enrolled across the six expansion cohorts; all received lorlatinib 100 mg once daily. Thirty-one ALK-rearranged patients previously treated with ≥1 ALK TKI (EXP2 to EXP5) were evaluable for ORR and 15 were evaluable for IC-ORR. The ORR and the IC-ORR for Japanese patients in EXP2-5 were 54.8% (95% confidence interval [CI]: 36.0-72.7) and 46.7% (95% CI: 21.3-73.4), respectively. Among patients who had received prior alectinib only (EXP3B), the ORR was 42.9%; 95% CI: 9.9-81.6). The most common treatment-related adverse event (TRAE) was hypercholesterolemia (79.5%). Hypertriglyceridemia was the most common grade 3/4 TRAE (25.6%). Single-dose and multiple-dose pharmacokinetic profiles among Japanese patients were similar to those in non-Japanese patients. Lorlatinib showed clinically meaningful responses and IC responses among ALK-rearranged Japanese patients with NSCLC who received ≥1 prior ALK TKI, including meaningful responses among those receiving prior alectinib only. Lorlatinib was generally well tolerated.

Simplified monitoring for hepatitis C virus treatment with glecaprevir plus pibrentasvir, a randomised non-inferiority trial.

BACKGROUND & AIMS: Direct-acting antiviral (DAA) therapy for HCV has high efficacy and limited toxicity. We hypothesised that the efficacy of glecaprevir-pibrentasvir for chronic HCV with a simplified treatment monitoring schedule would be non-inferior to a standard treatment monitoring schedule. METHODS: In this open-label multicentre phase IIIb trial, treatment-naïve adults with chronic HCV without cirrhosis were randomly assigned (2:1) to receive glecaprevir-pibrentasvir 300 mg-120 mg daily for 8 weeks administered with a simplified or standard monitoring strategy. Clinic visits occurred at baseline and post-treatment week 12 in the simplified arm, and at baseline, week 4, week 8, and post-treatment week 12 in the standard arm. Study nurse phone contact occurred at week 4 and week 8 in both arms. Participants requiring adherence support were not eligible, including those reporting recent injecting drug use. The primary endpoint was sustained virological response at post-treatment week 12 (SVR12), with a non-inferiority margin of 6%. RESULTS: Overall, 380 participants (60% male, 47% genotype 1, 32% genotype 3) with chronic HCV were randomised and treated with glecaprevir-pibrentasvir in the simplified (n = 253) and standard (n = 127) arms. In the intention-to-treat population, SVR12 was 92% (95% CI 89%-95%) in the simplified and 95% (95% CI 92%-99%) in the standard arm (difference between arms -3.2%; 95% CI -8.2% to 1.8%) and did not reach non-inferiority. In the per-protocol population, SVR12 was 97% (95% CI 96%-99%) in the simplified and 98% (95% CI 96%-100%) in the standard arm. No treatment-related serious adverse events were reported. CONCLUSIONS: In patients with chronic HCV infection without cirrhosis, treatment with glecaprevir-pibrentasvir was safe and effective. In comparison to standard monitoring, a simplified monitoring schedule did not achieve non-inferiority. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT03117569. LAY SUMMARY: Direct-acting antiviral (DAA) therapy for hepatitis C is highly effective and well tolerated. The SMART-C randomised trial evaluated an 8-week regimen of glecaprevir-pibrentasvir for hepatitis C treatment, using a simplified monitoring schedule that included no pathology tests or clinic visits during treatment. This simplified strategy produced a high cure rate (92%), but this was not equivalent to the standard monitoring schedule cure rate (95%).

Glecaprevir/pibrentasvir for 8 weeks in treatment-naïve patients with chronic HCV genotypes 1-6 and compensated cirrhosis: The EXPEDITION-8 trial.

BACKGROUND & AIMS: Eight-week glecaprevir/pibrentasvir leads to high rates of sustained virological response at post-treatment week 12 (SVR12) across HCV genotypes (GT) 1-6 in treatment-naïve patients without cirrhosis. We evaluated glecaprevir/pibrentasvir once daily for 8 weeks in treatment-naïve patients with compensated cirrhosis. METHODS: EXPEDITION-8 was a single-arm, multicenter, phase IIIb trial. The primary and key secondary efficacy analyses were to compare the lower bound of the 95% CI of the SVR12 rate in i) patients with GT1,2,4-6 in the per protocol (PP) population, ii) patients with GT1,2,4-6 in the intention-to-treat (ITT) population, iii) patients with GT1-6 in the PP population, and iv) patients with GT1-6 in the ITT population, to pre-defined efficacy thresholds based on historical SVR12 rates for 12 weeks of glecaprevir/pibrentasvir in the same populations. Safety was also assessed. RESULTS: A total of 343 patients were enrolled. Most patients were male (63%), white (83%), and had GT1 (67%). The SVR12 rate in patients with GT1-6 was 99.7% (n/N = 334/335; 95%CI 98.3-99.9) in the PP population and 97.7% (n/N = 335/343; 95% CI 96.1-99.3) in the ITT population. All primary and key secondary efficacy analyses were achieved. One patient (GT3a) experienced relapse (0.3%) at post-treatment week 4. Common adverse events (≥5%) were fatigue (9%), pruritus (8%), headache (8%), and nausea (6%). Serious adverse events (none related) occurred in 2% of patients. No adverse event led to study drug discontinuation. Clinically significant laboratory abnormalities were infrequent. CONCLUSIONS: Eight-week glecaprevir/pibrentasvir was well tolerated and led to a similarly high SVR12 rate as the 12-week regimen in treatment-naïve patients with chronic HCV GT1-6 infection and compensated cirrhosis. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03089944. LAY SUMMARY: This study was the first to evaluate an 8-week direct-acting antiviral (DAA) regimen active against all major types of hepatitis C virus (HCV) in untreated patients with compensated cirrhosis. High virological cure rates were achieved with glecaprevir/pibrentasvir across HCV genotypes 1-6, and these high cure rates did not depend on any patient or viral characteristics present before treatment. This may simplify care and allow non-specialist healthcare professionals to treat these patients, contributing to global efforts to eliminate HCV.

Estimating Efflux Transporter-Mediated Disposition of Molecules beyond the Rule of Five (bRo5) Using Transporter Gene Knockout Rats.

Transporter gene knockout models are a practical and widely used tool for pharmacokinetic studies in drug discovery. P-glycoprotein (P-gp) and breast cancer resistance protein (Bcrp) are major efflux transporters that control absorption and bioavailability, and are important when determining oral drug disposition. To the best of our knowledge, beyond the rule of five (bRo5) molecules launched on the market to date tend to be substrates for efflux transporters. The purpose of this study is to evaluate in vivo the impact of efflux transporters on the oral absorption process and systemic clearance using rats which lack P-gp and/or Bcrp expression. We administered five bRo5 substrates (asunaprevir, cyclosporine, danoprevir, ledipasvir, and simeprevir) intravenously or orally to wild-type and Mdr1a, Bcrp, and Mdr1a/Bcrp knockout rats, calculated the clearance, oral bioavailability, and absorption rate profile of each substrate, and compared the results. Systemic clearance of the substrates in knockout rats changed within approximately ±40% compared to wild-types, suggesting the efflux transporters do not have a significant influence on clearance in rats. On the other hand, the oral absorption of substrates in the knockout rats, especially those lacking Mdr1a, increased greatly-between 2- and 5-fold more than in wild-types. This suggests that rat efflux transporters, especially P-gp, greatly reduce the oral exposure of these substrates. Moreover, results on the absorption rate-time profile suggest that efflux transporters are constantly active during the absorption period in rats. Transporter knockout rats are a useful in vivo tool for estimating the transporter-mediated disposition of bRo5 molecules in drug discovery.

Safety and efficacy of direct-acting antivirals for chronic hepatitis C in patients with chronic kidney disease.

BACKGROUND: This is a real-world evidence study that aims to analyze the efficacy, tolerability and safety profile of paritaprevir/ombitasvir/ritonavir and dasabuvir, in patients with renal impairment. METHODS: We conducted an observational prospective study, on 232 patients with chronic kidney disease, undergoing treatment with paritaprevir/ombitasvir/ritonavir and dasabuvir, for chronic hepatitis C infection - genotype 1b. Renal and liver function were assessed at the beginning of therapy, monthly during treatment and three months after therapy completion. RESULTS: All patients achieved sustained virologic response. Common side effects were nausea, fatigue and headache. Close monitoring of tacrolimus blood levels and dose reduction was required in kidney transplant recipients. CONCLUSIONS: HCV therapy in the setting of renal dysfunction has always been a challenging topic. Direct-acting antivirals have shown promising effects, demonstrating good tolerance and efficacy in patients with HCV infection and renal impairment. Sustained virologic response within our study population was 100%.

Geldanamycin induces apoptosis and inhibits inflammation in fibroblast-like synoviocytes isolated from rheumatoid arthritis patients.

Rheumatoid arthritis (RA) is an autoimmune disease of the joints characterized by synovial hyperplasia and chronic inflammation. Fibroblasts-like synoviocytes (FLS), major cells in the synovium, together with infiltrated leukocytes, contribute greatly to RA progression. In our study, we hypothesized that geldanamycin (GA), a cancer drug might be able to inhibit RA FLS growth. To test the idea, RA FLS were isolated and cultured for cancer drug test. The results showed that GA can specifically inhibit the growth of RA FLS compared with normal FLS. Essentially, GA was found to promote reactive oxygen species production in RA FLS and induce programmed cell death. The annexinV/propidium iodide and terminal deoxynucleotidyl transferase dUTP nick-end labeling staining confirmed that GA can directly induce apoptosis and subsequently inhibit the growth of RA FLS, which was also confirmed by Western blot assay. In addition, our data demonstrated that inflammation was inhibited by suppressed nuclear factor κB signaling pathway. The therapeutic effect of GA was explored in collagen-induced arthritis mice. In short, GA was a promising drug for the treatment of RA by specifically inhibiting the proliferation and inflammation of RA FLS.

Clinical Management of Adverse Events Associated with Lorlatinib.

Lorlatinib is a novel, highly potent, brain-penetrant, third-generation ALK/ROS1 tyrosine kinase inhibitor (TKI), which has broad-spectrum potency against most known resistance mutations that can develop during treatment with crizotinib and second-generation ALK TKIs. The safety profile of lorlatinib was established based on 295 patients who had received the recommended dose of lorlatinib 100 mg once daily. Adverse events associated with lorlatinib are primarily mild to moderate in severity, with hypercholesterolemia (82.4%), hypertriglyceridemia (60.7%), edema (51.2%), peripheral neuropathy (43.7%), and central nervous system effects (39.7%) among the most frequently reported. These can be effectively managed with dose modification and/or standard supportive medical therapy, as indicated by a low incidence of permanent discontinuations due to adverse reactions. Most patients (81.0%) received at least one lipid-lowering agent. Prescription of supportive therapy should also consider the potential for drug-drug interactions with lorlatinib via engagement of specific CYP450 enzymes. This article summarizes the clinical experience from lorlatinib phase I investigators and was generated from discussion and review of the clinical study protocol and database to provide an expert consensus opinion on the management of the key adverse reactions reported with lorlatinib, including hyperlipidemia, central nervous system effects, weight increase, edema, peripheral neuropathy, and gastrointestinal effects. Overall, lorlatinib 100 mg once daily has a unique safety profile to be considered when prescribed, based on the recent U.S. Food and Drug Administration approval, for the treatment of patients with ALK-positive metastatic non-small cell lung cancer previously treated with a second-generation ALK TKI. IMPLICATIONS FOR PRACTICE: Despite the advancement of second-generation anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors (TKIs), the emergence of resistance and progression of central nervous system metastases remain clinically significant problems in ALK-positive non-small cell lung cancer. Lorlatinib is a potent, brain-penetrant, third-generation, macrocyclic ALK/ROS1 TKI, with broad-spectrum potency against most known resistance mutations that can develop during treatment with existing first- and second-generation ALK TKIs. This article provides recommendations for the clinical management of key adverse reactions reported with lorlatinib.

Intracranial remission with brigatinib rechallenge as fifth-line ALK inhibition therapy in a lung cancer patient.

Several anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors have been developed for the treatment of EML4-ALK-rearranged non-small-cell lung cancer, with the newer generation agents brigatinib, alectinib and lorlatinib showing pronounced central nervous system activities. Intracranial efficacy is an important feature for these agents, as metastatic lesions frequently occur in the central nervous system in the ALK-positive setting. Here, we report on an updated case of a patient who received her diagnosis in 2005 and has had disease progression with new lesions on six occasions over the last 8 years. During the first two progressions, only local recurrence was observed. After that, the lungs stayed clear and the patient progressed exclusively in the brain and spinal cord. Initial treatments consisted of chemotherapy and radiotherapy. In 2012, ALK-directed targeted therapy became available, and crizotinib was administered. The treatment was switched to brigatinib 3 years later because of spinal cord lesions. Brigatinib induced partial remission and was followed by lorlatinib and, later on, alectinib, when new metastases arose in the spinal cord and brain. Each of these drugs promoted complete remission of the recent lesions. In November 2018, imaging showed multiple cerebral metastases. As radiotherapy was not an option because of previous irradiation, and as chemotherapy cannot be expected to be active in the brain, the patient underwent brigatinib rechallenge, which led to partial remission. All of the central nervous system relapses were symptomatic, with symptoms resolved rapidly during treatment. This case of a patient with EML4-ALK-rearranged non-small-cell lung cancer shows that sequential treatment with next-generation ALK tyrosine kinase inhibitors, including rechallenge, can induce profound remission even in heavily pretreated patients, especially if the central nervous system is the site of progression.

HSP90 regulates larval settlement of the bryozoan Bugula neritina through the nitric oxide pathway.

The larvae of many sessile marine invertebrates go through a settlement process, during which planktonic larvae attach to a substrate and metamorphose into sessile juveniles. Larval attachment and metamorphosis (herein defined as 'settlement') are complex processes mediated by many signalling pathways. Nitric oxide (NO) signalling is one of the pathways that inhibits larval settlement in marine invertebrates across different phyla. NO is synthesized by NO synthase (NOS), which is a client of the molecular chaperone heat shock protein 90 (HSP90). In the present study, we provide evidence that NO, a gaseous messenger, regulates larval settlement of Bugula neritina By using pharmacological bioassays and western blotting, we demonstrated that NO inhibits larval settlement of B. neritina and that NO signals occur mainly in the sensory organ of swimming larvae. The settlement rate of B. neritina larvae decreased after heat shock treatment. Inhibition of HSP90 induced larval settlement, and attenuated the inhibition of NO donors during larval settlement. In addition, the expression level of both HSP90 and NOS declined upon settlement. These results demonstrate that HSP90 regulates the larval settlement of B. neritina by interacting with the NO pathway.

DZ-2384 has a superior preclinical profile to taxanes for the treatment of triple-negative breast cancer and is synergistic with anti-CTLA-4 immunotherapy.

Triple-negative breast cancer (TNBC) is typically aggressive, difficult to treat, and commonly metastasizes to the visceral organs and soft tissues, including the lungs and the brain. Taxanes represent the most effective and widely used therapeutic class in metastatic TNBC but possess limiting adverse effects that often result in a delay, reduction, or cessation of their use. DZ-2384 is a candidate microtubule-targeting agent with a distinct mechanism of action and strong activity in several preclinical cancer models, with reduced toxicities. DZ-2384 is highly effective in patient-derived taxane-sensitive and taxane-resistant xenograft models of TNBC at lower doses and over a wider range relative to paclitaxel. When comparing compound exposure at minimum effective doses relative to safe exposure levels, the therapeutic window for DZ-2384 is 14-32 compared with 2.0 and less than 2.8 for paclitaxel and docetaxel, respectively. DZ-2384 is effective at reducing brain metastatic lesions when used at maximum tolerated doses and is equivalent to paclitaxel. Drug distribution experiments indicate that DZ-2384 is taken up more efficiently by tumor tissue but at equivalent levels in the brain compared with paclitaxel. Selective DZ-2384 uptake by tumor tissue may in part account for its wider therapeutic window compared with taxanes. In view of the current clinical efforts to combine chemotherapy with immune checkpoint inhibitors, we demonstrate that DZ-2384 acts synergistically with anti-CTLA-4 immunotherapy in a syngeneic murine model. These results demonstrate that DZ-2384 has a superior pharmacologic profile over currently used taxanes and is a promising therapeutic agent for the treatment of metastatic TNBC.

Image-guided photo-therapeutic nanoporphyrin synergized HSP90 inhibitor in patient-derived xenograft bladder cancer model.

Photodynamic therapy is a promising and effective non-invasive therapeutic approach for the treatment of bladder cancers. Therapies targeting HSP90 have the advantage of tumor cell selectivity and have shown great preclinical efficacy. In this study, we evaluated a novel multifunctional nanoporphyrin platform loaded with an HSP90 inhibitor 17AAG (NP-AAG) for use as a multi-modality therapy against bladder cancer. NP-AAG was efficiently accumulated and retained at bladder cancer patient-derived xenograft (PDX) over 7 days. PDX tumors could be synergistically eradicated with a single intravenous injection of NP-AAG followed by multiple light treatments within 7 days. NP-AAG mediated treatment could not only specifically deliver 17AAG and produce heat and reactive oxygen species, but also more effectively inhibit essential bladder cancer essential signaling molecules like Akt, Src, and Erk, as well as HIF-1α induced by photo-therapy. This multifunctional nanoplatform has high clinical relevance and could dramatically improve management for bladder cancers with minimal toxicity.

The Hsp90 inhibitor 17-DMAG decreases infection of porcine circovirus type 2 in mice.

Although several factors affecting porcine circovirus type 2 (PCV2) infection have been reported, their precise roles are far from clear. The aim of this study was to determine whether 17-dimethylaminoethylamino-17-demethoxygeldanamycin (17-DMAG), an inhibitor of Hsp90, could significantly affect PCV2 infection and immune responses in BALB/c mice. Intraperitoneal injection of 17-DMAG significantly reduced viral loads in the blood and tissues of mice infected with PCV2, compared with control groups. The 17-DMAG treatment decreased serum interleukin (IL)-10 and tumor necrosis factor(TNF)-α levels, but it did not have a significant effect on the IL-1ß level. These data demonstrate that 17-DMAG is highly effective in suppressing PCV2 replication in BALB/c mice, indicating that it has potential value as an antiviral drug against PCV2 infection.

Enhanced effect of geldanamycin nanocomposite against breast cancer cells growing in vitro and as xenograft with vanquished normal cell toxicity.

Despite enormous advances in remedies developed for breast cancer, an effective therapeutic strategy by targeting malignant cells with the least normal tissue toxicity is yet to be developed. Hsp90 is considered to be an important therapeutic target to inhibit cell proliferation. Geldanamycin (GDM), a potent inhibitor of Hsp90 was withdrawn from clinical trials due to its undesirable hepatotoxicity. We report a superparamagnetic iron oxide (SPION) based polymeric nanocomposite of GDM augmenting anticancer competence with decreased hepatic toxicity. The particle size of nanocomposite was ascertained to be 76±10nm with acceptable stability. A comparative dose dependent in vitro validation of cytotoxicity showed an enhanced cellular damage and necrosis in breast cancer (MCF-7) cell line at a low dose of 5.49nM (in GDM nanocomposite) in contrast to 20nM of pure GDM, while normal breast epithelial cells (MCF-10A) were least affected. Besides, in vivo study (in breast cancer xenografts) substantiated 2.7 fold delay in tumor progression mediated by redundancy in the downstream functions of p-Akt and MAPK-Erk leading to apoptosis with negligible hepatotoxicity. Pure GDM disrupted the function and morphology of liver with lesser therapeutic efficacy than the GDM nanocomposite. These findings deduce that GDM based polymeric magnetite nanocomposite play a vital role in efficacious therapy while vanquishing normal cells and hepatic toxicity and thereby promising it to be reinstated in clinics.

Delivery of HSP90 Inhibitor Using Water Soluble Polymeric Conjugates with High Drug Payload.

PURPOSE: HSP90 (Heat shock protein 90kD) has been validated as a therapeutic target in Castrate Resistant Prostate Cancer. Unfortunately, HSP90 inhibitors suffer from dose-limiting toxicities that hinder their clinical applications. Previously developed polymeric delivery systems for HSP90 inhibitors had either low drug content or low biological activity suggesting the need for better delivery system for HSP90 inhibitors. METHODS: We developed a simplified synthetic strategy to prepare polyethylene glycol based water-soluble polymeric system for model HSP90 inhibitor geldanamycin (GDM). We then investigated the effect of cathepsin B degradable linker and drug content in polymeric conjugates on their growth inhibitory property using DU145 (androgen independent) and LNCaP (androgen dependent) cell lines. RESULTS: Water-soluble polymeric conjugates were synthesized with GDM content ranging from 9 to 30% wt/wt. We demonstrated the importance of cathepsin B degradable linker from the context of drug content and different prostate cancer cell lines. The most active conjugate against DU145 cells exhibited IC50 value of 2.9 µM. This was similar to the IC50 (2.1 µM) of small molecular drug aminohexane geldanamycin. CONCLUSION: Water-soluble polymeric conjugate with high drug content was synthesized that exhibited in-vitro growth inhibitory activity similar to small molecular weight HSP90 inhibitor. Graphical Abstract Water soluble degradable polymeric conjugate for the delivery of Geldanamycin.

Pharmacological or Genetic Activation of Hsp70 Protects against Loss of Parkin Function.

Mutations of parkin are a prevalent genetic contributor to familial Parkinson's disease (PD). As a key regulator of protein and mitochondrial homeostasis, parkin plays a pivotal role in maintaining dopaminergic neuronal survival. However, whereas Drosophila parkin null mutants exhibit prominent parkinsonian features, parkin-deficient mice generally lack an overt phenotype. Here, we found that the expression of Hsp70 along with several other members of the chaperone family is elevated in parkin null mice, suggesting a possible compensatory mechanism for the loss of parkin function in these mice that could have masked their phenotype. Supporting this, we demonstrate that the enhancement of chaperone function induced either pharmacologically via 17-AAG treatment or genetically via Hsp70 overexpression can protect cells against proteolytic and mitochondrial stress in a manner that is similar to that brought about by parkin overexpression. Importantly, we further showed that enhanced chaperone activity can ameliorate the pathological phenotypes in Drosophila parkin null mutants, which suggests the ability of chaperones to phenocopy parkin function. Taken together, our results suggest that Hsp members may act as compensatory factors for parkin loss of function and that the exploitation of these factors may be of potential therapeutic value.