Seang Yiv

Nanoscale liposomal formulation of a SYK P-site inhibitor against B-precursor leukemia

We report preclinical proof of principle for effective treatment of B-precursor acute lymphoblastic leukemia (ALL) by targeting the spleen tyrosine kinase (SYK)-dependent antiapoptotic blast cell survival machinery with a unique nanoscale pharmaceutical composition. This nanoscale liposomal formulation (NLF) contains the pentapeptide mimic 1,4-Bis (9-O dihydroquinidinyl) phthalazine/hydroquinidine 1,4-phathalazinediyl diether (C61) as the first and only selective inhibitor of the substrate binding P-site of SYK. The C61 NLF exhibited a very favorable pharmacokinetic and safety profile in mice, induced apoptosis in primary B-precursor ALL blast cells taken directly from patients as well as in vivo clonogenic ALL xenograft cells, destroyed the in vivo clonogenic fraction of ALL blast cells, and, at nontoxic dose levels, exhibited potent in vivo antileukemic activity against patient-derived ALL cells in xenograft models of aggressive B-precursor ALL. Our findings establish SYK as an attractive molecular target for therapy of B-precursor ALL. Further development of the C61 NLF may provide the foundation for therapeutic innovation against therapy-refractory B-precursor ALL.

GM-144, a novel lipophilic vaginal contraceptive gel-microemulsion

In a systematic effort to develop a dual-function intravaginal spermicide as well as a drug delivery vehicle against sexually transmitted pathogens, a submicron particle size (30–80 nm), lipophilic and spermicidal gel-microemulsion (viz GM-144) containing the pharmaceutical excipients propylene glycol, Captex 300, Cremophor EL, Phospholipon 90G, Rhodigel, Pluronic F-68, and sodium benzoate was formulated. GM-144 completely immobilized sperm in human or rabbit semen in less than 30 seconds. Therefore, thein vivo contraceptive potency of intravaginally applied GM-144 was compared in the standard rabbit model to those of the detergent spermicide, nonoxynol-9 (N-9)-containing formulation. Eighty-four ovulated New Zealand White rabbits in subgroups of 28 were artificially inseminated with and without intravaginal administration of GM-144 or 2% N-9 (Gynol II) formulation and allowed to complete term pregnancy. GM-144 showed remarkable contraceptive activity in the rigorous rabbit model. When compared with control, intravaginal administration of GM-144 and Gynol II resulted in 75% and 70.8% inhibition of fertility (P<.0001 versus control, Fisher’s exact test), respectively. Thus, GM-144 as a vaginal contraceptive was as effective as the commercially available N-9 gel. In the rabbit vaginal irritation test, none of the 6 rabbits given daily intravaginal application of spermicidal GM-144 for 10 days developed epithelial ulceration, edema, leukocyte influx, or vascular congestion characteristic of inflammation (total score = 5). Therefore, GM-144 has the potential to become a clinically useful safe vaginal contraceptive and a vehicle for formulating lipophilic drugs used in reducing the risk of heterosexual transmission of sexually tranmitted diseases.

Evaluation of subchronic (13-week) and reproductive toxicity potential of intravaginal gel–microemulsion formulation of a dual-function phenyl phosphate derivative of bromo-methoxy zidovudine (compound whi-07) in B6C3F1 mice

Heterosexual transmission of human immunodeficiency virus (HIV) accounts for 90% of all new infections worldwide and significantly contributes to new acquired immunodeficiency syndrome (AIDS) cases in the USA. In a systematic effort to develop a microbicidal contraceptive capable of preventing HIV transmission as well as providing fertility control, we previously identified novel phenyl phosphate derivatives of 3′‐azido‐3′‐deoxythymidine (zidovudine) that exhibit potent anti‐HIV and spermicidal activities. This study reports the preclinical studies of our lead compound WHI‐07, 5‐bromo‐6‐methoxy‐5,6‐dihydro‐3′‐azidothymidine‐5′‐(p‐bromophenyl) methoxyalaninyl phosphate, for use as a dual‐function topical microbicide. In vivo toxicity studies in non‐human primates and rodents given WHI‐07 (20 mg kg−1) intravenously and intraperitonealy, respectively, had no detectable adverse effects on hematological and clinical chemistry profiles. The 13‐week subchronic and reproductive toxicity potential of an intravaginal gel–microemulsion formulation of WHI‐07 was studied in mice to support its further development as a dual‐function microbicide. Groups of ten female B6C3F1 mice were exposed intravaginally to a gel–microemulsion formulation containing 0, 0.5, 1.0 or 2.0% WHI‐07, 5 days a week, for 13 consecutive weeks. On a molar basis, these concentrations represent 1400–5700 times their in vitro spermicidal potency EC50) and 1.4 × 106–5.7 × 106 times their in vitro anti‐HIV activity50). After 13 weeks of intravaginal treatment, half of the treated mice were evaluated for toxicity and the other half were mated with untreated males to evaluate potential reproductive and developmental effects. The endpoints that were evaluated included survival, body weight gain, hematological and clinical chemistries, absolute and relative organ weights and histopathology. The WHI‐07 applications did not cause weight loss, morbidity, mortality or specific tissue lesions detectable by histopathology. Repeated intravaginal exposure of mice to WHI‐05 for 13 weeks had no adverse effects on subsequent reproductive performance (100% fertile), neonatal survival (>95%) or pup development. These findings collectively show that the experimental dual‐function anti‐HIV and contraceptive agent WHI‐07 did not cause significant acute or subchronic toxicity. Copyright

Contraceptive efficacy and safety studies of a novel microemulsion-based lipophilic vaginal spermicide

OBJECTIVE To investigate the in vivo contraceptive potency and safety of a novel microemulsion-based lipophilic vaginal spermicide. DESIGN In vitro and in vivo spermicidal activity and safety of a submicron-particle-size, lipophilic gel-microemulsion (GM-4). SETTING Center for Advanced Preclinical Sciences at the Parker Hughes Institute. PATIENT(S) Nine male volunteer sperm donors. INTERVENTION(S) Motile human sperm in semen and medium were exposed to eight GM-4 components or GM-4 formulation. Forty-eight ovulated NZW rabbits in subgroups of 16 with or without intravaginal administration of GM-4 or nonoxynol-9 gel (N-9; Gynol II) were artificially inseminated and allowed to complete pregnancy. Eleven rabbits were exposed to daily intravaginal application of GM-4 with and without N-9 for 10 consecutive days. Ten of 20 B(6)C(3)F(1) mice were given repetitive intravaginal application of GM-4 for 5 days/week over 13 consecutive weeks. MAIN OUTCOME MEASURE(S) The motility of human sperm treated with GM-4 components and GM-4. Term pregnancy in rabbits and histopathological grading of rabbit vaginal tissue for irritation. Evaluation of mice for survival, growth, hematologic parameters, blood-chemistry profiles, absolute and relative organ weights, and histopathology. RESULT(S) The individual components of GM-4 lacked spermicidal activity in human semen, whereas the GM-4 formulation containing all the eight pharmacological excipients exhibited potent spermicidal activity with rapid kinetics. GM-4 showed remarkable contraceptive activity in the rigorous rabbit model. None of the 16 (0%) rabbits given GM-4 intravaginally before artificial insemination became pregnant. By contrast, 15 of 16 (93.7%) control rabbits and 5 of 16 (31.2%) Gynol II-treated rabbits became pregnant and delivered newborns. Thus, GM-4 was a significantly more effective contraceptive than a commercially available N-9 gel [100% vs. 68.7% protection; P< 0.05, Fishers exact test]. Unlike the rabbits treated with N-9, none of the rabbits that were given GM-4 intravaginally for 10 consecutive days developed epithelial ulceration, edema, leukocyte influx, or vascular congestion characteristic of inflammation. Furthermore, repeated intravaginal application of GM-4 for up to 13 weeks in mice had no adverse effects on survival, growth, metabolism, or organ function. CONCLUSION We conclude that the novel spermicidal GM-4 formulation is safe and significantly more effective than N-9 in preventing conception.

In vivo Anti-Cancer Activity of a Liposomal Nanoparticle Construct of Multifunctional Tyrosine Kinase Inhibitor 4-(4'-Hydroxyphenyl)-Amino-6,7-Dimethoxyquinazoline

The quinazoline derivative 4-(4’-hydroxyphenyl)-amino-6,7-dimethoxyquinazoline (WHI-P131/JANEX-1; CAS 202475-60-3) is a dual-function inhibitor of Janus kinase 3 (JAK3) and Epidermal Growth Factor (EGF) receptor kinase. A PEGylated liposomal nanoparticle formulation of GMP-grade WHI-P131 exhibited potent in vivo activity against breast cancer cells. Notably, this therapeutic nanoparticle formulation of GMP-grade WHI-P131 was substantially more effective than the standard chemotherapy drugs paclitaxel, gemcitabine, and ge fi tinib against chemotherapy-resistant breast cancer in the MMTV/ Neu transgenic mouse model. These experimental results demonstrate that the nanotechnology- enabled delivery of WHI-P131 shows therapeutic potential against breast cancer.

A novel vaginal microbicide containing the rationally designed anti-HIV compound HI-443 (N′-[2-(2-thiophene)ethyl]-N′-[2-(5-bromopyridyl)] thiourea])

Introduction: A focal point in contemporary research aimed at preventing the heterosexual spread of AIDS has been the development of intravaginal anti-HIV microbicides to curb the mucosal human immunodeficiency virus type 1 (HIV-1) transmission. Areas covered: This article reviews the preclinical activity and safety profile of the thiophene thiourea PETT derivative, HI-443 (N′-[2-(2-thiophene)ethyl]-N′-[2-(5-bromopyridyl)] thiourea]). HI-443 is a rationally designed non-nucleoside reverse transcriptase inhibitor (NNRTI) with unprecedented activity against primary clinical HIV-1 isolates with NRTI or NNRTI resistance, multidrug resistance as well as non-B envelope subtypes of HIV-1. HI-443 exhibited a favorable toxicity and pharmacokinetics profile following oral, intraperitoneal or intravenous administration in rodents and a favorable safety profile after repeated intravaginal dosing via a gel formulation in rabbits and pigs. HI-443 did not induce the secretion of pro-inflammatory cytokines and chemokines by three-dimensional reconstituted human vaginal epithelia integrating Langerhans cells ex vivo or in the in vivo porcine model at therapeutic dose levels. Intravaginally administered HI-443 prevented vaginal transmission of a drug-resistant clinical HIV-1 isolate in the surrogate Hu-PBL-SCID mouse model of AIDS. Expert opinion: The discovery of HI-443 as a non-spermicidal broad-spectrum antiretroviral agent represents a significant step forward in the development of a prophylactic microbicide without contraceptive activity for curbing heterosexual HIV transmission.

Therapeutic nanoparticle constructs of a JAK3 tyrosine kinase inhibitor against human B-lineage ALL cells

WHI-P131 (CAS 202475-60-3) is a dual-function inhibitor of JAK3 tyrosine kinase that demonstrated potent in vivo anti-inflammatory and anti-leukemic activity in several preclinical animal models. This is the first report of the development of nanoparticle (NP) constructs ofWHI-P131. Fourty-eight distinct NP formulations were prepared and WHI-P131 encapsulation efficiencies > 95% and intraliposomal WHI-P131 concentrations >10 mg/mL were achieved in lead NP formulations. The anti-cancer activity of WHI-P131-NP, a PEGylated lead formulation was tested in vitro and in vivo. Notably, WHI-P131-NP was capable of causing apoptotic death in primary leukemia cells from chemotherapy-resistant acute lymphoblastic leukemia (ALL) as well as chronic lymphocytic leukemia (CLL) patients. WHI-P131-NP was also active in the RS4;11 SCID mouse xenograft model of chemotherapy-resistant B-lineage ALL. The life table analysis showed that WHI-P131-NP was more effective than WHI-P131 (P = 0.01), vincristine (P < 0.0001), or vehicle (P < 0.0001). These experimental results demonstrate that the nanotechnology-enabled delivery of WHI-P131 shows therapeutic potential against leukemias with constitutive activation of the JAK3-STAT3/STAT5 molecular target.

CD19-antigen specific nanoscale liposomal formulation of a SYK P-site inhibitor causes apoptotic destruction of human B-precursor leukemia cells

We report the anti-leukemic potency of a unique biotargeted nanoscale liposomal nanoparticle (LNP) formulation of the spleen tyrosine kinase (SYK) P-site inhibitor C61. C61-loaded LNP were decorated with a murine CD19-specific monoclonal antibody directed against radiation-resistant CD19-receptor positive aggressive B-precursor acute lymphoblastic leukemia (ALL) cells. The biotargeted C61-LNP were more potent than untargeted C61-LNP and consistently caused apoptosis in B-precursor ALL cells. The CD19-directed C61-LNP also destroyed B-precursor ALL xenograft cells and their leukemia-initiating in vivo clonogenic fraction. This unique nanostructural therapeutic modality targeting the SYK-dependent anti-apoptotic blast cell survival machinery shows promise for overcoming the clinical radiochemotherapy resistance of B-precursor ALL cells.