Assessment of antidiabetic effect of 4-HIL in type 2 diabetic and healthy Sprague Dawley rats.

Type 2 diabetes mellitus (T2DM) is a metabolic disorder characterized by chronic hyperglycemia and insulin resistance. 4-hydroxyisoleucine (4-HIL) is a non-proteinogenic amino acid isolated from the fenugreek seeds and has enormous pharmacological activities. The present study was undertaken to investigate the antihyperglycemic effect of 4-HIL in streptozotocin (STZ)-induced diabetic rats. Moreover, its toxicity was evaluated in vitro and in vivo employing human embryonic kidney cells (HEK-293) and healthy rats, respectively. In experiment 1, STZ-induced diabetic male rats were subjected to an oral treatment of 4-HIL (100 mg/kg), while experiment 2 deals with the effects of 4-HIL on healthy male and female rats following oral administration. The treatment (experiment 1) declined the elevated blood glucose level, feed intake, and increased body weight(s). Additionally, blood glucose impairment was improved as observed by OGTT and IPGT tests. Pancreatic histopathology revealed mild changes in the 4-HIL group. Moreover, experiment 2 showed increased body weight, normal blood glucose levels (male-106.06 ± 7.49 mg/dl and female-100.06 ± 14.69 mg/dL), hematological parameters, and histopathological profiles in the treatment group. 4-HIL did not affect the viability of HEK-293 cells, and no signs of toxicity were observed in healthy rats. Therefore, the study concludes that 4-HIL has potential antihyperglycemic activity without any toxic effects.

Regulatory safety pharmacology and toxicity assessments of a standardized stem extract of Cassia occidentalis Linn. in rodents.

Cassia occidentalis Linn (CO) is an annual/perennial plant having traditional uses in the treatments of ringworm, gastrointestinal ailments and piles, bone fracture, and wound healing. Previously, we confirmed the medicinal use of the stem extract (ethanolic) of CO (henceforth CSE) in fracture healing at 250 mg/kg dose in rats and described an osteogenic mode of action of four phytochemicals present in CSE. Here we studied CSE's preclinical safety and toxicity. CSE prepared as per regulations of Current Good Manufacturing Practice for human pharmaceuticals/phytopharmaceuticals and all studies were performed in rodents in a GLP-accredited facility. In acute dose toxicity as per New Drug and Clinical Trial Rules, 2019 (prior name schedule Y), in rats and mice and ten-day dose range-finding study in rats, CSE showed no mortality and no gross abnormality at 2500 mg/kg dose. Safety Pharmacology showed no adverse effect on central nervous system, cardiovascular system, and respiratory system at 2500 mg/kg dose. CSE was not mutagenic in the Ames test and did not cause clastogenicity assessed by in vivo bone marrow genotoxicity assay. By a sub chronic (90 days) repeated dose (as per OECD, 408 guideline) study in rats, the no-observed-adverse-effect-level was found to be 2500 mg/kg assessed by clinico-biochemistry and all organs histopathology. We conclude that CSE is safe up to 10X the dose required for its osteogenic effect.

Preclinical Development of MGC018, a Duocarmycin-based Antibody-drug Conjugate Targeting B7-H3 for Solid Cancer.

B7-H3, also referred to as CD276, is a member of the B7 family of immune regulatory proteins. B7-H3 is overexpressed on many solid cancers, including prostate cancer, renal cell carcinoma, melanoma, squamous cell carcinoma of the head and neck, non-small cell lung cancer, and breast cancer. Overexpression of B7-H3 is associated with disease severity, risk of recurrence and reduced survival. In this article, we report the preclinical development of MGC018, an antibody-drug conjugate targeted against B7-H3. MGC018 is comprised of the cleavable linker-duocarmycin payload, valine-citrulline-seco duocarmycin hydroxybenzamide azaindole (vc-seco-DUBA), conjugated to an anti-B7-H3 humanized IgG1/kappa mAb through reduced interchain disulfides, with an average drug-to-antibody ratio of approximately 2.7. MGC018 exhibited cytotoxicity toward B7-H3-positive human tumor cell lines, and exhibited bystander killing of target-negative tumor cells when cocultured with B7-H3-positive tumor cells. MGC018 displayed potent antitumor activity in preclinical tumor models of breast, ovarian, and lung cancer, as well as melanoma. In addition, antitumor activity was observed toward patient-derived xenograft models of breast, prostate, and head and neck cancer displaying heterogeneous expression of B7-H3. Importantly, MGC018 exhibited a favorable pharmacokinetic and safety profile in cynomolgus monkeys following repeat-dose administration. The antitumor activity observed preclinically with MGC018, together with the positive safety profile, provides evidence of a potentially favorable therapeutic index and supports the continued development of MGC018 for the treatment of solid cancers. GRAPHICAL ABSTRACT: http://mct.aacrjournals.org/content/molcanther/19/11/2235/F1.large.jpg.

Predicting toxicities in humans by nonclinical safety testing: an update with particular reference to anticancer compounds.

The sensitivity of the various preclinical models used to predict toxicity in humans varies. In this review, we analyze the various models used to predict safety in drug discovery and development with a view to understanding their translational value in humans. Twenty recently approved anticancer drugs were studied and the available nonclinical and clinical adverse effects information available from the US Food and Drug Administration (FDA) was analyzed. We found that gastrointestinal and hematopoietic toxicities in humans were predicted to the maximum extent by nonclinical models, whereas respiratory, integumentary, renal, nervous, hepatic, and cardiovascular were moderately predicted. Ocular, endocrine, and musculoskeletal toxicities were poorly predicted while lymphatic and immune toxicities were difficult to predict.

Preparation and Preclinical Evaluation of Inhalable Particles Containing Rapamycin and Anti-Tuberculosis Agents for Induction of Autophagy.

PURPOSE: Mycobacterium tuberculosis (Mtb) inhibits host defense mechanisms, including autophagy. We investigated particles containing rapamycin (RAP) alone or in combination with isoniazid (INH) and rifabutin (RFB) for: targeting lung macrophages on inhalation; inducing autophagy; and killing macrophage-resident Mtb and/or augmenting anti-tuberculosis (TB) drugs. METHODS: PLGA and drugs were spray-dried. Pharmacokinetics, partial biodistribution (LC-MS/MS) and efficacy (colony forming units, qPCR, acid fast staining, histopathology) in mice following dry powder inhalation were evaluated. RESULTS: Aerodynamic diameters of formulations were 0.7-4.7 µm. Inhaled particles reached deep lungs and were phagocytosed by alveolar macrophages, yielding AUC0-48 of 102 compared to 0.1 µg/ml × h obtained with equivalent intravenous dose. RAP particles induced more autophagy in Mtb-infected macrophages than solutions. Inhaled particles containing RAP alone in daily, alternate-day and weekly dosing regimens reduced bacterial burden in lungs and spleens, inducing autophagy and phagosome-lysosome fusion. Inhalation of particles containing RAP with INH and RFB cleared the lungs and spleens of culturable bacteria. CONCLUSIONS: Targeting a potent autophagy-inducing agent to airway and lung macrophages alone is feasible, but not sufficient to eliminate Mtb. Combination of macrophage-targeted inhaled RAP with classical anti-TB drugs contributes to restoring tissue architecture and killing Mtb.

Withania somnifera shows a protective effect in monocrotaline-induced pulmonary hypertension.

CONTEXT: Withania somnifera (Linn.) Dunal (Solanaceae), a clinically used herbal drug in Ayurveda, shows potent antioxidant, anti-inflammatory, pro-apoptotic, and cardioprotective effects. However, the efficacy of W. somnifera in pulmonary hypertension (PH), a cardiopulmonary disorder, remains unexplored. OBJECTIVE: The present study investigates the effect of W. somnifera root powder on monocrotaline (MCT)-induced PH in rats. MATERIALS AND METHODS: In preventive studies, W. somnifera root powder (50 and 100 mg/kg/d, p.o.) was administered from day 1 following single administration of MCT (60 mg/kg, s.c.) in Sprague-Dawley (SD) rats. After 35 d, right ventricular pressure (RVP) was measured in anesthetized rats. Various physical markers of right ventricular hypertrophy (RVH) were measured in isolated hearts. Markers of endothelial function, inflammation, and oxidative stress were estimated in lung homogenate. Vasoreactivity of pulmonary arteries was also studied. In therapeutic treatment, W. somnifera (50 and 100 mg/kg/d, p.o.) was administered from day 21 to 35 post-MCT administration. RESULTS: Preventive treatment with 50 and 100 mg/kg W. somnifera significantly reduced the RVP (32.18 ± 1.273 mm Hg and 29.98 ± 1.119 mm Hg, respectively, versus 42.96 ± 1.789 mm Hg of MCT) and all markers of RVH in MCT-challenged rats. There was an improvement in inflammation, oxidative stress and endothelial dysfunction, and attenuation of proliferative marker and apoptotic resistance in lungs. Therapeutic treatment with W. somnifera (100 mg/kg) also reduced RVP and RVH. DISCUSSION: This study demonstrated that W. somnifera significantly protected against MCT-induced PH due to its antioxidant, anti-inflammatory, pro-apoptotic, and cardioprotective properties.

Symplocos cochinchinensis attenuates streptozotocin-diabetes induced pathophysiological alterations of liver, kidney, pancreas and eye lens in rats.

The beneficial effects of hydroethanol extract of Symplocos cochinchinensis (SCE) has been explored against hyperglycemia associated secondary complications in streptozotocin induced diabetic rat model. The experimental groups consist of normal control (NC), diabetic control (DC), DC + metformin 100 mg kg(-1) bwd, DC + SCE 250 and DC + SCE 500. SCEs and metformin were administered daily for 21 days and sacrificed on day 22. Oral glucose tolerance test, plasma insulin, % HbA1c, urea, creatinine, aspartate aminotransferase, alanine aminotransferase, albumin, total protein etc. were analysed. Aldose reductase (AR) activity in the eye lens was also checked. On day 21, DC rats showed significantly abnormal glucose response, HOMA-IR, % HbA1c, decreased activity of antioxidant enzymes and GSH, elevated AR activity, hepatic and renal oxidative stress markers like malondialdehyde, protein carbonyls compared to NC. DC rats also exhibited increased level of plasma urea and creatinine. Treatment with SCE protected from the deleterious alterations of biochemical parameters in a dose dependent manner including histopathological alterations in pancreas. SCE 500 exhibited 46.28% of glucose lowering effect and decreased HOMA-IR (2.47), % HbA1c (6.61), lens AR activity (15.99%), and hepatic, renal oxidative stress and function markers compared to DC group. Considerable amount of liver and muscle glycogen was replenished by SCE treatment in diabetic animals. Although metformin showed better effect, the activity of SCE was very much comparable with this drug.

Estrogen receptor potentiates mTORC2 signaling in breast cancer cells by upregulating superoxide anions.

The estrogen receptor (ER) plays a cardinal role in estrogen-responsive breast carcinogenesis. It is, however, unclear as to how estrogen-ER interaction potentiates breast cancer progression. Compelling evidence supports estrogen-induced redox alterations, such as augmented reactive oxygen species (ROS) levels, as having a crucial role in breast carcinogenesis. Despite ER being a biological mediator of the majority of estrogen-induced cellular responses; its role in estrogen-induced tissue-specific ROS generation remains largely debatable. We examined a panel of human breast cancer specimens and found that ER-positive breast cancer specimens exhibited a higher incidence of augmented O(2)(•-) levels compared to matched normal tissue. ROS are known to function as signal transducers and ROS-mediated signaling remains a key complementary mechanism that drives carcinogenesis by activating redox-sensitive oncogenic pathways. Additional studies revealed that augmented O(2)(•-) levels in breast cancer specimens coincided with mammalian target of rapamycin complex 2 (mTORC2) hyperactivation. Detailed investigations using in vitro experiments established that 17ß-estradiol (E2)-stimulated breast cancer cells exhibited transiently upregulated O(2)(•-) levels, with the presence of ER being a crucial determinant for the phenomenon to take place. Gene expression, ER transactivation, and confocal studies revealed that the E2-induced transient O(2)(•-) upregulation was effected by ER through a nongenomic pathway possibly involving mitochondria. Furthermore, E2 treatment activated mTORC2 in breast cancer cells in a characteristically ER-dependent manner. Interestingly, altering O(2)(•-) anion levels through chemical/genetic methods caused significant modulation of the mTORC2 signaling cascade. Taken together, our findings unravel a novel nongenomic pathway unique to estrogen-responsive breast cancer cells wherein, upon stimulation by E2, ER may regulate mTORC2 activity in a redox-dependent manner by transiently modulating O(2)(•-) levels particularly within mitochondria. The findings suggest that therapies aimed at counteracting these redox alterations and/or resultant signaling cascades may complement conventional treatments for estrogen-responsive breast cancer.

Some observations on the tropism of Japanese encephalitis virus in rat brain.

The clinical picture of viral encephalitis is determined by the affinity and persistence of the virus to different brain regions. Therefore, the present study was aimed to investigate the neuropathological changes following Japanese encephalitis virus (JEV) infection in rat at different time points. Twelve days old Wistar rats were infected by intracerebral inoculation of JEV. Presence of JEV antigen was detected in thalamus, striatum, cortex and mid brain on 3, 6, 10 and 20 days post inoculation (d.p.i.). Histopathological changes were also studied in different brain regions at different time points. The highest expression of JEV antigen was found on 6 dpi in all the brain regions studied. JEV antigen was maximum in thalamus on 6 d.p.i. and mid brain on 10 d.p.i. JEV antigen, however, was almost undetectable on 20 d.p.i. in all the regions. The classical pathological changes such as cellular infiltration, perivascular cuffing, meningeal disruption, neuronal damage, neuronal shrinkage, and plaque formation were observed up to 10 d.p.i. The present study reveals high affinity of JEV to thalamus, brainstem and striatum. Rat model of JEV infection may serve as a useful model for studying mechanism of cell injury and recovery in JE.

Prophylactic potential of liposomized integral membrane protein of Plasmodium yoelii nigeriensis against blood stage infection in BALB/c mice.

Triton X-114 phase separated integral membrane proteins (IMPs) of a multidrug resistant strain of Plasmodium yoelii nigeriensis (P. yoelii) were screened for their potential to impart protection against malaria infection in BALB/c mice. As revealed by immunoblotting, antibodies present in parasite specific sera from convalescent (protected) as well as immunized (partially protected) animals recognized different membrane proteins. A thorough investigation reveals that P. yoelii specific convalescent sera recognized IMPs with molecular masses ranging from 21 to 81 kDa. Among various membrane proteins, the IMPs corresponding to 81 and 66 kDa molecular weight were highly prominent in the immunoblots probed with the sera from convalescent animals, whereas sera from immunized animals failed to produce impressive band pattern. Immunofluorescence assay revealed that the 66-kDa IMP specific antibodies reacted with fixed smears of mature schizonts and merozoites. Further immunization with 66 kDa IMP (PyIMP) purified through polyclonal IgG sepharose 4B affinity did not impart effective immune response (in its free form) and could provided partial protection only. On the other hand, animals immunized with 66 kDa PyIMP entrapped in phosphatidyl-choline/cholesterol (PC/chol) liposomes protected BALB/c mice against lethal P. yoelii challenge.

Evaluation of anti-ulcerogenic and ulcer-healing properties of Ocimum sanctum Linn.

Ocimum sanctum (OS) is known to possess various therapeutic properties. We evaluated its anti-ulcerogenic activity in cold restraint (CRU), aspirin (ASP), alcohol (AL), pyloric ligation (PL) induced gastric ulcer models in Sprague-Dawley rats, histamine-induced duodenal (HST) ulcer in guinea pigs, and ulcer-healing activity, in acetic acid-induced (AC) chronic ulcer model. We found that OS, decreased the incidence of ulcers and also enhanced the healing of ulcers. OS at a dose of 100 mg/kg was found to be effective in CRU (65.07%), ASP (63.49%), AL (53.87%), PL (62.06%), and HST (61.76%) induced ulcer models and significantly reduced free, total acidity and peptic activity by 72.58, 58.63, 57.6%, respectively, and increased mucin secretion by 34.61%. Additionally, OS completely healed the ulcers within 20 days of treatment in AC. We observed that anti-ulcer effect of OS may be due to its cytoprotective effect rather than antisecretory activity. Conclusively, OS was found to possess potent anti-ulcerogenic as well as ulcer-healing properties and could act as a potent therapeutic agent against peptic ulcer disease.