Skp2 E3 ligase is overexpressed in numerous human cancers and plays a critical role in cell-cycle progression, senescence, metabolism, cancer progression, and metastasis. In the present study, we ...identified a specific Skp2 inhibitor using high-throughput in silico screening of large and diverse chemical libraries. This Skp2 inhibitor selectively suppresses Skp2 E3 ligase activity, but not activity of other SCF complexes. It also phenocopies the effects observed upon genetic Skp2 deficiency, such as suppressing survival and Akt-mediated glycolysis and triggering p53-independent cellular senescence. Strikingly, we discovered a critical function of Skp2 in positively regulating cancer stem cell populations and self-renewal ability through genetic and pharmacological approaches. Notably, Skp2 inhibitor exhibits potent antitumor activities in multiple animal models and cooperates with chemotherapeutic agents to reduce cancer cell survival. Our study thus provides pharmacological evidence that Skp2 is a promising target for restricting cancer stem cell and cancer progression.
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•Integrated computational approaches identify a specific Skp2 inhibitor•The Skp2 inhibitor selectively impairs Skp2 activity and functions•Skp2 inactivation restricts cancer stemness and potentiates chemotherapy sensitivity•The Skp2 inhibitor exhibits potent antitumor activity
A selective Skp2 inhibitor identified through a virtual chemical screen suppresses cancer stem cell renewal and cancer progression, establishing Skp2 as a promising target for cancer treatment.
Small-cell lung cancer (SCLC), an aggressive neuroendocrine tumor with early dissemination and dismal prognosis, accounts for 15-20% of lung cancer cases and ∼200,000 deaths each year. Most cases are ...inoperable, and biopsies to investigate SCLC biology are rarely obtainable. Circulating tumor cells (CTCs), which are prevalent in SCLC, present a readily accessible 'liquid biopsy'. Here we show that CTCs from patients with either chemosensitive or chemorefractory SCLC are tumorigenic in immune-compromised mice, and the resultant CTC-derived explants (CDXs) mirror the donor patient's response to platinum and etoposide chemotherapy. Genomic analysis of isolated CTCs revealed considerable similarity to the corresponding CDX. Most marked differences were observed between CDXs from patients with different clinical outcomes. These data demonstrate that CTC molecular analysis via serial blood sampling could facilitate delivery of personalized medicine for SCLC. CDXs are readily passaged, and these unique mouse models provide tractable systems for therapy testing and understanding drug resistance mechanisms.
Even when trained under exactly the same conditions outbred male Sprague-Dawley (SD) rats vary in the form of the Pavlovian conditioned approach response (CR) they acquire. The form of the CR (i.e. ...sign-tracking vs. goal-tracking) predicts to what degree individuals attribute incentive salience to cues associated with food or drugs. However, we have noticed variation in the incidence of these two phenotypes in rats obtained from different vendors. In this study, we quantified sign- and goal-tracking behavior in a reasonably large sample of SD rats obtained from two vendors (Harlan or Charles River), as well as from individual colonies operated by both vendors. Our sample of rats acquired from Harlan had, on average, more sign-trackers than goal-trackers, and vice versa for our sample of rats acquired from Charles River. Furthermore, there were significant differences among colonies of the same vendor. Although it is impossible to rule out environmental variables, SD rats at different vendors and barriers may have reduced phenotypic heterogeneity as a result of genetic variables, such as random genetic drift or population bottlenecks. Consistent with this hypothesis, we identified marked population structure among colonies from Harlan. Therefore, despite sharing the same name, investigators should be aware that important genetic and phenotypic differences exist among SD rats from different vendors or even from different colonies of the same vendor. If used judiciously this can be an asset to experimental design, but it can also be a pitfall for those unaware of the issue.
In most patients with small-cell lung cancer (SCLC)-a metastatic, aggressive disease-the condition is initially chemosensitive but then relapses with acquired chemoresistance. In a minority of ...patients, however, relapse occurs within 3 months of initial treatment; in these cases, disease is defined as chemorefractory. The molecular mechanisms that differentiate chemosensitive from chemorefractory disease are currently unknown. To identify genetic features that distinguish chemosensitive from chemorefractory disease, we examined copy-number aberrations (CNAs) in circulating tumor cells (CTCs) from pretreatment SCLC blood samples. After analysis of 88 CTCs isolated from 13 patients (training set), we generated a CNA-based classifier that we validated in 18 additional patients (testing set, 112 CTC samples) and in six SCLC patient-derived CTC explant tumors. The classifier correctly assigned 83.3% of the cases as chemorefractory or chemosensitive. Furthermore, a significant difference was observed in progression-free survival (PFS) (Kaplan-Meier P value = 0.0166) between patients designated as chemorefractory or chemosensitive by using the baseline CNA classifier. Notably, CTC CNA profiles obtained at relapse from five patients with initially chemosensitive disease did not switch to a chemorefractory CNA profile, which suggests that the genetic basis for initial chemoresistance differs from that underlying acquired chemoresistance.
Summary Background A substantial impediment to progress in trials of new therapies in neuromuscular disorders is the absence of responsive outcome measures that correlate with patient functional ...deficits and are sensitive to early disease processes. Irrespective of the primary molecular defect, neuromuscular disorder pathological processes include disturbance of intramuscular water distribution followed by intramuscular fat accumulation, both quantifiable by MRI. In pathologically distinct neuromuscular disorders, we aimed to determine the comparative responsiveness of MRI outcome measures over 1 year, the validity of MRI outcome measures by cross-sectional correlation against functionally relevant clinical measures, and the sensitivity of specific MRI indices to early muscle water changes before intramuscular fat accumulation beyond the healthy control range. Methods We did a prospective observational cohort study of patients with either Charcot-Marie-Tooth disease 1A or inclusion body myositis who were attending the inherited neuropathy or muscle clinics at the Medical Research Council (MRC) Centre for Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, London, UK. Genetic confirmation of the chromosome 17p11·2 duplication was required for Charcot-Marie-Tooth disease 1A, and classification as pathologically or clinically definite by MRC criteria was required for inclusion body myositis. Exclusion criteria were concomitant diseases and safety-related MRI contraindications. Healthy age-matched and sex-matched controls were also recruited. Assessments were done at baseline and 1 year. The MRI outcomes—fat fraction, transverse relaxation time (T2), and magnetisation transfer ratio (MTR)—were analysed during the 12-month follow-up, by measuring correlation with functionally relevant clinical measures, and for T2 and MTR, sensitivity in muscles with fat fraction less than the 95th percentile of the control group. Findings Between Jan 19, 2010, and July 7, 2011, we recruited 20 patients with Charcot-Marie-Tooth disease 1A, 20 patients with inclusion body myositis, and 29 healthy controls (allocated to one or both of the 20-participant matched-control subgroups). Whole muscle fat fraction increased significantly during the 12-month follow-up at calf level (mean absolute change 1·2%, 95% CI 0·5–1·9, p=0·002) but not thigh level (0·2%, −0·2 to 0·6, p=0·38) in patients with Charcot-Marie-Tooth disease 1A, and at calf level (2·6%, 1·3–4·0, p=0·002) and thigh level (3·3%, 1·8–4·9, p=0·0007) in patients with inclusion body myositis. Fat fraction correlated with the lower limb components of the inclusion body myositis functional rating score (ρ=–0·64, p=0·002) and the Charcot-Marie-Tooth examination score (ρ=0·63, p=0·003). Longitudinal T2 and MTR changed consistently with fat fraction but more variably. In muscles with a fat fraction lower than the control group 95th percentile, T2 was increased in patients compared with controls (regression coefficients: inclusion body myositis thigh 4·0 ms SE 0·5, calf 3·5 ms 0·6; Charcot-Marie-Tooth 1A thigh 1·0 ms 0·3, calf 2·0 ms 0·3) and MTR reduced compared with controls (inclusion body myositis thigh −1·5 percentage units pu; 0·2, calf −1·1 pu 0·2; Charcot-Marie-Tooth 1A thigh −0·3 pu 0·1, calf −0·7 pu 0·1). Interpretation MRI outcome measures can monitor intramuscular fat accumulation with high responsiveness, show validity by correlation with conventional functional measures, and detect muscle water changes preceding marked intramuscular fat accumulation. Confirmation of our results in further cohorts with these and other muscle-wasting disorders would suggest that MRI biomarkers might prove valuable in experimental trials. Funding Medical Research Council UK.
The monocarboxylate transporter 1 (MCT1) inhibitor, AZD3965, is undergoing phase I evaluation in the United Kingdom. AZD3965 is proposed, via lactate transport modulation, to kill tumor cells reliant ...on glycolysis. We investigated the therapeutic potential of AZD3965 in small cell lung cancer (SCLC) seeking rationale for clinical testing in this disease and putative predictive biomarkers for trial use.
AZD3965 sensitivity was determined for seven SCLC cell lines, in normoxia and hypoxia, and for a tumor xenograft model. Proof of mechanism was sought via changes in intracellular/tumor lactate. Expression of MCT1 and related transporter MCT4 was assessed by Western blot analysis. Drug resistance was investigated via MCT4 siRNAi and overexpression. The expression and clinical significance of MCT1 and MCT4 were explored in a tissue microarray (TMA) from 78 patients with SCLC.
AZD3965 sensitivity varied in vitro and was highest in hypoxia. Resistance in hypoxia was associated with increased MCT4 expression. In vivo, AZD3965 reduced tumor growth and increased intratumor lactate. In the TMA, high MCT1 expression was associated with worse prognosis (P = 0.014). MCT1 and hypoxia marker CA IX expression in the absence of MCT4 was observed in 21% of SCLC tumors.
This study provides a rationale to test AZD3965 in patients with SCLC. Our results suggest that patients with tumors expressing MCT1 and lacking in MCT4 are most likely to respond.
Outcome measures for clinical trials in neuromuscular diseases are typically based on physical assessments which are dependent on patient effort, combine the effort of different muscle groups, and ...may not be sensitive to progression over short trial periods in slow-progressing diseases. We hypothesised that quantitative fat imaging by MRI (Dixon technique) could provide more discriminating quantitative, patient-independent measurements of the progress of muscle fat replacement within individual muscle groups.
To determine whether quantitative fat imaging could measure disease progression in a cohort of limb-girdle muscular dystrophy 2I (LGMD2I) patients over a 12 month period.
32 adult patients (17 male;15 female) from 4 European tertiary referral centres with the homozygous c.826C>A mutation in the fukutin-related protein gene (FKRP) completed baseline and follow up measurements 12 months later. Quantitative fat imaging was performed and muscle fat fraction change was compared with (i) muscle strength and function assessed using standardized physical tests and (ii) standard T1-weighted MRI graded on a 6 point scale.
There was a significant increase in muscle fat fraction in 9 of the 14 muscles analyzed using the quantitative MRI technique from baseline to 12 months follow up. Changes were not seen in the conventional longitudinal physical assessments or in qualitative scoring of the T₁w images.
Quantitative muscle MRI, using the Dixon technique, could be used as an important longitudinal outcome measure to assess muscle pathology and monitor therapeutic efficacy in patients with LGMD2I.
ABSTRACT
Purpose
Design and evaluation of a novel laser-based method for micromoulding of microneedle arrays from polymeric materials under ambient conditions. The aim of this study was to optimise ...polymeric composition and assess the performance of microneedle devices that possess different geometries.
Methods
A range of microneedle geometries was engineered into silicone micromoulds, and their physicochemical features were subsequently characterised.
Results
Microneedles micromoulded from 20% w/w aqueous blends of the mucoadhesive copolymer Gantrez® AN-139 were surprisingly found to possess superior physical strength than those produced from commonly used pharma polymers. Gantrez® AN-139 microneedles, 600 μm and 900 μm in height, penetrated neonatal porcine skin with low application forces (>0.03 N per microneedle). When theophylline was loaded into 600 μm microneedles, 83% of the incorporated drug was delivered across neonatal porcine skin over 24 h. Optical coherence tomography (OCT) showed that drug-free 600 μm Gantrez® AN-139 microneedles punctured the
stratum corneum
barrier of human skin
in vivo
and extended approximately 460 µm into the skin. However, the entirety of the microneedle lengths was not inserted.
Conclusion
In this study, we have shown that a novel laser engineering method can be used in micromoulding of polymeric microneedle arrays. We are currently carrying out an extensive OCT-informed study investigating the influence of microneedle array geometry on skin penetration depth, with a view to enhanced transdermal drug delivery from optimised laser-engineered Gantrez® AN-139 microneedles.
Introduced in 1987, platinum-based chemotherapy remains standard of care for small cell lung cancer (SCLC), a most aggressive, recalcitrant tumor. Prominent barriers to progress are paucity of tumor ...tissue to identify drug targets and patient-relevant models to interrogate novel therapies. Following our development of circulating tumor cell patient-derived explants (CDX) as models that faithfully mirror patient disease, here we exploit CDX to examine new therapeutic options for SCLC.
We investigated the efficacy of the PARP inhibitor olaparib alone or in combination with the WEE1 kinase inhibitor AZD1775 in 10 phenotypically distinct SCLC CDX
and/or
These CDX represent chemosensitive and chemorefractory disease including the first reported paired CDX generated longitudinally before treatment and upon disease progression.
There was a heterogeneous depth and duration of response to olaparib/AZD1775 that diminished when tested at disease progression. However, efficacy of this combination consistently exceeded that of cisplatin/etoposide, with cures in one CDX model. Genomic and protein analyses revealed defects in homologous recombination repair genes and oncogenes that induce replication stress (such as MYC family members), predisposed CDX to combined olaparib/AZD1775 sensitivity, although universal predictors of response were not noted.
These preclinical data provide a strong rationale to trial this combination in the clinic informed by prevalent, readily accessed circulating tumor cell-based biomarkers. New therapies will be evaluated in SCLC patients after first-line chemotherapy, and our data suggest that the combination of olaparib/AZD1775 should be used as early as possible and before disease relapse.
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