Discovery and Optimization of Potent, Selective, and Brain-Penetrant 1-Heteroaryl-1H-Indazole LRRK2 Kinase Inhibitors for the Treatment of Parkinson's Disease.

Inhibition of leucine-rich repeat kinase 2 (LRRK2) kinase activity represents a genetically supported, chemically tractable, and potentially disease-modifying mechanism to treat Parkinson's disease. Herein, we describe the optimization of a novel series of potent, selective, central nervous system (CNS)-penetrant 1-heteroaryl-1H-indazole type I (ATP competitive) LRRK2 inhibitors. Type I ATP-competitive kinase physicochemical properties were integrated with CNS drug-like properties through a combination of structure-based drug design and parallel medicinal chemistry enabled by sp3-sp2 cross-coupling technologies. This resulted in the discovery of a unique sp3-rich spirocarbonitrile motif that imparted extraordinary potency, pharmacokinetics, and favorable CNS drug-like properties. The lead compound, 25, demonstrated exceptional on-target potency in human peripheral blood mononuclear cells, excellent off-target kinase selectivity, and good brain exposure in rat, culminating in a low projected human dose and a pre-clinical safety profile that warranted advancement toward pre-clinical candidate enabling studies.

Structure-Guided Discovery of Aminoquinazolines as Brain-Penetrant and Selective LRRK2 Inhibitors.

The leucine-rich repeat kinase 2 (LRRK2) protein has been genetically and functionally linked to Parkinson's disease (PD), a disabling and progressive neurodegenerative disorder whose current therapies are limited in scope and efficacy. In this report, we describe a rigorous hit-to-lead optimization campaign supported by structural enablement, which culminated in the discovery of brain-penetrant, candidate-quality molecules as represented by compounds 22 and 24. These compounds exhibit remarkable selectivity against the kinome and offer good oral bioavailability and low projected human doses. Furthermore, they showcase the implementation of stereochemical design elements that serve to enable a potency- and selectivity-enhancing increase in polarity and hydrogen bond donor (HBD) count while maintaining a central nervous system-friendly profile typified by low levels of transporter-mediated efflux and encouraging brain penetration in preclinical models.

Discovery of TAK-981, a First-in-Class Inhibitor of SUMO-Activating Enzyme for the Treatment of Cancer.

SUMOylation is a reversible post-translational modification that regulates protein function through covalent attachment of small ubiquitin-like modifier (SUMO) proteins. The process of SUMOylating proteins involves an enzymatic cascade, the first step of which entails the activation of a SUMO protein through an ATP-dependent process catalyzed by SUMO-activating enzyme (SAE). Here, we describe the identification of TAK-981, a mechanism-based inhibitor of SAE which forms a SUMO-TAK-981 adduct as the inhibitory species within the enzyme catalytic site. Optimization of selectivity against related enzymes as well as enhancement of mean residence time of the adduct were critical to the identification of compounds with potent cellular pathway inhibition and ultimately a prolonged pharmacodynamic effect and efficacy in preclinical tumor models, culminating in the identification of the clinical molecule TAK-981.

Probing the roles of SUMOylation in cancer cell biology by using a selective SAE inhibitor.

Small ubiquitin-like modifier (SUMO) family proteins regulate target-protein functions by post-translational modification. However, a potent and selective inhibitor targeting the SUMO pathway has been lacking. Here we describe ML-792, a mechanism-based SUMO-activating enzyme (SAE) inhibitor with nanomolar potency in cellular assays. ML-792 selectively blocks SAE enzyme activity and total SUMOylation, thus decreasing cancer cell proliferation. Moreover, we found that induction of the MYC oncogene increased the ML-792-mediated viability effect in cancer cells, thus indicating a potential application of SAE inhibitors in treating MYC-amplified tumors. Using ML-792, we further explored the critical roles of SUMOylation in mitotic progression and chromosome segregation. Furthermore, expression of an SAE catalytic-subunit (UBA2) S95N M97T mutant rescued SUMOylation loss and the mitotic defect induced by ML-792, thus confirming the selectivity of ML-792. As a potent and selective SAE inhibitor, ML-792 provides rapid loss of endogenously SUMOylated proteins, thereby facilitating novel insights into SUMO biology.

MLN8054 and Alisertib (MLN8237): Discovery of Selective Oral Aurora A Inhibitors.

The Aurora kinases are essential for cell mitosis, and the dysregulation of Aurora A and B have been linked to the etiology of human cancers. Investigational agents MLN8054 (8) and alisertib (MLN8237, 10) have been identified as high affinity, selective, orally bioavailable inhibitors of Aurora A that have advanced into human clinical trials. Alisertib (10) is currently being evaluated in multiple Phase II and III clinical trials in hematological malignancies and solid tumors.

Discovery of a potent and orally bioavailable benzolactam-derived inhibitor of Polo-like kinase 1 (MLN0905).

This article describes the discovery of a series of potent inhibitors of Polo-like kinase 1 (PLK1). Optimization of this benzolactam-derived chemical series produced an orally bioavailable inhibitor of PLK1 (12c, MLN0905). In vivo pharmacokinetic-pharmacodynamic experiments demonstrated prolonged mitotic arrest after oral administration of 12c to tumor bearing nude mice. A subsequent efficacy study in nude mice achieved tumor growth inhibition or regression in a human colon tumor (HT29) xenograft model.

Design and optimization of potent and orally bioavailable tetrahydronaphthalene Raf inhibitors.

Inhibition of mutant B-Raf signaling, through either direct inhibition of the enzyme or inhibition of MEK, the direct substrate of Raf, has been demonstrated preclinically to inhibit tumor growth. Very recently, treatment of B-Raf mutant melanoma patients with a selective B-Raf inhibitor has resulted in promising preliminary evidence of antitumor activity. This article describes the design and optimization of tetrahydronaphthalene-derived compounds as potent inhibitors of the Raf pathway in vitro and in vivo. These compounds possess good pharmacokinetic properties in rodents and inhibit B-Raf mutant tumor growth in mouse xenograft models.

Discovery and optimization of pyrazoline compounds as B-Raf inhibitors.

The discovery of novel pyrazoline derivatives as B-Raf (V600E) inhibitors is described in this report. Chemical modification of the pyrazoline scaffold led to the development of SAR and identified potent and selective inhibitors of B-Raf (V600E). Determination of the pharmacokinetic properties of selected inhibitors is also reported.

Effects of pre- and periconceptional undernutrition on arterial function in adult female sheep are vascular bed dependent.

The nutritional environment during development and even prior to conception may contribute to cardiovascular risk. In mature adult female sheep, we investigated the effect of preconceptional and periconceptional maternal nutritional restriction on the vascular reactivity of arteries from four vascular beds supplying the heart, thorax, kidney and hindlimb. Welsh Mountain ewes received 100% of nutrient requirements throughout gestation (control group, C, n = 18), or 50% of nutrient requirements for 30 days prior to conception (preconceptional group, PRE, n = 20) or for 15 days either side of conception (periconceptional group, PERI, n = 31) and 100% thereafter. In 3.5-year-old female offspring, the left anterior descending coronary (LAD), left internal thoracic (LITA), right renal and second and third order femoral arteries were dissected and their reactivity was assessed by organ bath or wire myography. Vasoconstrictor responses were greater in both LAD and LITA from PERI offspring compared with C (P < 0.01), while vasoconstriction was unaffected by maternal diet in arteries from the renal and femoral circulations (P = n.s.). Endothelium-dependent and -independent vasodilatation was attenuated in third order femoral arteries of PRE and PERI groups compared with C (P < 0.05). Endothelium-independent vasodilatation was attenuated in both the LAD and renal arteries in the PERI group compared with C (P < 0.05). These data show that moderate maternal undernutrition either prior to or around conception affects vascular function of adult offspring. The effect depends on the timing of the insult, but also on the vascular bed studied and vessel hierarchy in the vascular tree.

Localization of the full-thickness cartilage lesions in medial and lateral unicompartmental knee osteoarthritis.

This study's aim was to determine the patterns of osteoarthritis (OA) in both unicompartmental medial and lateral OA of the knee. Forty patients with medial and 20 with lateral unicompartmental knee osteoarthritis were studied to determine the location of full-thickness cartilage lesions. Intraoperatively, the distance between margins of the lesion and reference lines were measured. The femoral measurements were transposed onto lateral radiographs to determine the relationship between the lesion site and knee flexion angles. Both tibial and femoral lesions were significantly (p < 0.01) more posterior in lateral OA than medial OA. In medial OA, the lesion center was, on average, at 11 degrees (SD 3 degrees) of flexion, whereas in lateral OA, it was at 40 degrees (SD 3 degrees). The smallest medial femoral lesions were near full extension and, as they enlarged, they extended posteriorly. The smallest lateral femoral lesions extended from 20 degrees to 60 degrees flexion. As these lesions enlarged, they extended both anteriorly and posteriorly. There was a well-defined relationship between the site of the lesions and their size, suggesting that they develop and progress in a predictable manner. The relationship was different for medial and lateral OA, suggesting that different mechanical factors are important in initiating the different types of OA. The lesions in medial OA occur in extension, perhaps initiated by events occurring at heel strike. The lesions in lateral OA begin at flexion angles above those occurring during the single leg stance phase of the gait cycle, so activities other than gait are likely to induce lateral OA.

Mismatched pre- and postnatal nutrition leads to cardiovascular dysfunction and altered renal function in adulthood.

The early life environment has long-term implications for the risk of developing cardiovascular (CV) disease in adulthood. Fetal responses to changes in maternal nutrition may be of immediate benefit to the fetus, but the long-term effects of these adaptations may prove detrimental if nutrition in postnatal life does not match that predicted by the fetus on the basis of its prenatal environment. We tested this predictive adaptive response hypothesis with respect to CV function in sheep. We observed that a mismatch between pre- and postnatal nutrient environments induced an altered CV function in adult male sheep that was not seen when environments were similar. Sheep that received postnatal undernutrition alone had altered growth, CV function, and basal hypothalamo-pituitary-adrenal axis activity in adulthood. Prenatal undernutrition induced greater weight gain by weaning compared with the prenatal control diet, which may provide a reserve in the face of a predicted poor diet in later life. In an adequate postnatal nutrient environment (i.e., relatively mismatched), these offspring exhibited cardiac hypertrophy and altered CV function in adulthood. These data support the concept that adult CV function can be determined by developmental responses to intrauterine nutrition made in expectation of the postnatal nutritional environment, and that if these predictions are not met, the adult may be maladapted and at greater risk of CV disease. Our findings have substantial implications for devising strategies to reduce the impact of a mismatch in nutrition levels in humans undergoing rapid socio-economic transitions in both developing and developed societies.

The approach of fused fissures with fissureless technique decreases the incidence of persistent air leak after lobectomy.

OBJECTIVE: To evaluate two different approaches used to perform fused fissures in lobectomies in terms of persistent air leak (PAL) and their impact on length of hospital stay. METHODS: One hundred and nineteen patients underwent lobectomy or bilobectomy in our unit. We focused on patients with fused fissures (63 patients), all of whom were selected intraoperatively based on predefined criteria. These patients with incomplete fissures were randomly assigned to two groups: Group A patients who underwent a 'traditional technique' to approach fused fissures and Group B patients who underwent a 'fissureless technique'. The latter technique avoids dissecting the lung parenchyma over the pulmonary artery, reducing the chances of air leak. Patients in both groups had shown no significant difference in preoperative variables (p>0.05). RESULTS: The incidence of PAL was significantly higher among patients with incomplete or fused fissures (0 case vs 8 cases (Groups A and B), p<0.005). Furthermore, the incidence of PAL was significantly higher in the Group A (traditional technique) (7 vs 1) (p<0.05, OR=3.1, CI 0.22-0.51). The probability for air leak cessation was significantly higher in patients of Group B (fissureless technique) (log rank p<0.0001). The length of hospital stay was higher in Group A (5.76+/-3.1) compared with Group B (4.9+/-1.7) (p<0.05). No other variables were identified as risk factors for PAL in this series. CONCLUSIONS: The fissureless technique appears to be a superior approach for fused fissures in terms of both preventing persistent air leak and reducing the length of hospitalisation. This technique can be performed safely at no additional cost and without adverse consequences.

Identification and structure-activity relationships of a new series of Melanocortin-4 receptor antagonists.

The identification and optimization of a series of acylguanidine-based melanocortin-4 receptor antagonists is discussed.

Fetal origins of coronary heart disease-implications for cardiothoracic surgery?

Over the last 15 years, there has been growing evidence that poor nutrition during gestation plays an important role in the development of coronary heart disease. This hypothesis, commonly known as the 'fetal origins of adult disease' has now gained widespread acceptance in the scientific community. In this review, we discuss the evidence for this theory and analyse the patho-physiological mechanisms underlying the relationship between altered fetal growth and coronary heart disease. Finally, the potential relevance of the theory to cardiac surgical practice will be evaluated.