The novel phospho-non-steroidal anti-inflammatory drugs, OXT-328, MDC-22 and MDC-917, inhibit adjuvant-induced arthritis in rats

Phosphosulindac (OXT-328) prevents and reverses chemotherapy induced peripheral neuropathy in mice

Background

Chemotherapy-induced peripheral neuropathy (CIPN), a side effect of chemotherapy, is particularly difficult to treat. We explored whether phosphosulindac (PS), a modified NSAID, could treat CIPN.

Methods

CIPN was induced in male C57BL/6 J mice by paclitaxel, vincristine or oxaliplatin. Mechanical allodynia was measured with the von Frey test and cold allodynia with the acetone test. To determine the preventive effect of PS, it was administered 2 days before the induction of CIPN. Mouse Lewis lung carcinoma xenografts were used to determine if PS altered the chemotherapeutic efficacy of paclitaxel. Cultured cell lines were used to evaluate the effect of PS on neuroinflammation.

Results

Treatment with each of the three chemotherapeutic agents used to induce CIPN lowered the mechanical allodynia scores by 56 to 85% depending on the specific agent. PS gel was applied topically 3x/day for 16-22 days to the hind paws of mice with CIPN. This effect was dose-dependent. Unlike vehicle, PS returned mechanical allodynia scores back to pre-CIPN levels. PS had a similar effect on paclitaxel-induced CIPN cold allodynia. Sulindac, a metabolite of PS, had no effect on CIPN. PS significantly prevented CIPN compared to vehicle. Given concomitantly with paclitaxel to mice with lung cancer xenografts, PS relieved CIPN without affecting the anticancer effect of paclitaxel. The enantiomers of PS were equally efficacious against CIPN, suggesting the therapeutic suitability of the racemate PS. There were no apparent side effects of PS. PS suppressed the levels of IL-6, IL-10, CXCL1, and CXCL2 induced by paclitaxel in a neuroblastoma cell line, and macrophage activation to the M1 proinflammatory phenotype.

Conclusion

Topically applied PS demonstrated broad therapeutic and preventive efficacy against CIPN, preserved the anticancer effect of paclitaxel, and was safe. Its anti-CIPN effect appears to be mediated, in part, by suppression of neuroinflammation. These data support further evaluation of topical PS for the control of CIPN.

The Antiangiogenic Effect and Ocular Pharmacology of Novel Modified Nonsteroidal Anti-Inflammatory Drugs in the Treatment of Oxygen-Induced Retinopathy

Purpose: To evaluate the hypothesis that 3 novel compounds, OXT-328, Q-922, and CL-717 show efficacy in the treatment of oxygen-induced retinopathy (OIR) and whether or not their route of administration is intravitreal, topical, or systemic. Methods: The OIR mouse model, characterized by an avascular area (AVA) and a neovascular area (NVA) of the retina, was used to study retinopathy of prematurity and other retinal diseases characterized by abnormal vessel growth. We measured the effect of our compounds on both the AVA and NVA in whole mounts of mouse retinal tissue. We also evaluated their ability to prevent new vessel formation in chicken chorioallantoic membranes (CAMs). Finally, we measured the in vitro uptake and biodistribution of topically applied CL-717 in human eye explants. Results: In mice with OIR, compared to controls, a single intravitreal administration of Q-922 or OXT-328 significantly reduced both AVA and NVA. CL-717 administered as eye drops over 5 days also reduced AVA and NVA, whereas OXT-328 eye drops had no effect. Q-922 given intraperitoneal (150 mg/kg/day × 5 days) reduced AVA and NVA. Remarkably, explanted human eyes bathed in CL-717 show rapid uptake and biodistribution in ocular tissues. In the chicken CAM model, all 3 compounds reduced the formation of new blood vessels by about one-third. No side effect in mice was observed, except for mild ocular surface irritation with Q-922. Conclusions: Systemic administration of Q-922 or topical administration of CL-717 holds particular promise for a simplified treatment of proliferative retinopathies without the necessity of intravitreal injections.

Development of the PC-NSAID technology: From contact angle to Vazalore®

We describe strategies in drug development to reduce the gastrointestinal (GI) toxicity of nonsteroidal anti-inflammatory drugs (NSAIDs). We then provide an overview of the experiments that led to the development of PC-NSAIDs, a novel family of NSAIDs associated with phosphatidylcholine (PC) that have reduced GI toxicity and full therapeutic activity. Furthermore, we describe the evidence showing: that the stomach possesses hydrophobic properties that are attributable to phospholipids lining the mucus gel layer; and that NSAIDs chemically associate with intrinsic PC, thereby attenuating the tissue's hydrophobic properties. Further, pre-associating NSAIDs with PC reduces the GI toxicity of these drugs, both in rodent ulcer models and in human subjects, without affecting the drugs' therapeutic activity. Finally, we discuss the commercialization and launch of Aspirin-PC, an over-the-counter (OTC) drug with the brand name Vazalore®.

Phospho-Aspirin (MDC-22) inhibits pancreatic cancer growth in patient-derived tumor xenografts and KPC mice by targeting EGFR: Enhanced efficacy in combination with irinotecan

Novel therapeutic strategies are needed in the fight against pancreatic cancer. We have previously documented the chemopreventive effect of MDC-22 in preclinical models of pancreatic cancer. In the present work, we examined the therapeutic effects of MDC-22 in patient-derived tumor xenografts (PDTXs) and in LSL-Kras^G12D/+, LSL-Trp53^R172H/+, Pdx1-Cre (KPC) genetically engineered mice, two complementary and clinically relevant animal models of pancreatic cancer. In addition, we evaluated whether MDC-22 could synergize with current chemotherapeutic drugs used in the clinic. MDC-22 reduced the growth of various human pancreatic cancer cell lines in a concentration-dependent manner. In vivo, MDC-22 strongly reduced patient-derived pancreatic tumor xenograft growth by 50%, and extended survival of LSL-Kras^G12D/+; LSL-Trp53^R172H/+; Pdx1-Cre (KPC) mice by over a month (5.3 months versus 7.0 months). In both models, MDC-22 inhibited EGFR activation and its downstream signals, including ERK and FAK phosphorylation. In human pancreatic cancer cell lines, MDC-22 enhanced the growth inhibitory effect of irinotecan, and to a lesser degree those of gemcitabine and nab-paclitaxel. Normal human pancreatic epithelial cells were more resistant to the cytotoxic effects of, both, MDC-22 alone or in combination with irinotecan, indicating selectivity. Furthermore, MDC-22 enhanced irinotecan's effect on cell migration, in part, by inhibiting EGFR/FAK signaling. Collectively, our results indicate that MDC-22 is an effective anticancer drug in preclinical models of pancreatic cancer, and suggest that MDC-22 plus irinotecan as drug combination strategy for pancreatic cancer treatment, which warrants further evaluation.

Aspirin-Based Organoiron Dendrimers as Promising Anti-Inflammatory, Anticancer, and Antimicrobial Drugs

Designing nanocarriers with actions directed at a specific organ or tissue is a very promising strategy since it can significantly reduce the toxicity of a bioactive drug. In this study, an organometallic dendrimer was used to synthesize a biocompatible drug delivery system by attaching aspirin to the periphery of the dendrimer. Our goal is to enhance the bioavailability and anticancer activity of aspirin and reduce its toxicity through successive generations of organoiron dendrimers. The biological activity of aspirin-based dendrimer complexes was evaluated. The result of antimicrobial activity of the synthesized dendrimers also demonstrated an increase in their antimicrobial activity with increased generation of the dendrimers for most types of microorganisms. This study reveals for the first time that organoiron dendrimers linked with aspirin exhibit an excellent Gram-negative activity comparable to the reference drug Gentamicin. All synthesized dendrimers were tested for their anticancer activity against breast cancer cell lines (MCF-7), hepatocellular cell lines (Hep-G2), and a non-cancer cell line, Human Embryonic Kidney (HEK293), using the MTT cell viability assay and compared against a standard anticancer drug, Doxorubicin. Compounds G3-D9-Asp and G4-D12-Asp exhibited noticeable activity against both cell lines, both of which were more effective than aspirin itself. In addition, the in vivo anti-inflammatory activity and histopathology of swollen paws showed that the designed aspirin-based dendrimers displayed significant anti-inflammatory activity; however, G2-D6-Asp showed the best anti-inflammatory activity, which was more potent than the reference drug aspirin during the same period. Moreover, the coupling of aspirin to the periphery of organoiron dendrimers showed a significant reduction in the toxicity of aspirin on the stomach.

Phospho-Sulindac (OXT-328) Inhibits Dry Eye Disease in Rabbits: A Dose-, Formulation- and Structure-Dependent Effect

Purpose: Inflammation of the ocular surface is central to dry eye disease (DED). The anti-inflammatory agent phospho-sulindac (PS) at a high dose was efficacious against DED in a rabbit model. We assessed the dose, formulation and structure dependence of PS's effect. Methods: In rabbits with concanavalin A-induced DED we evaluated a range of PS concentrations (0.05%-1.6%) and dosing frequencies, assessed the duration of its effect with PS in 2 solution formulations and one emulsion formulation, and compared the efficacy of PS to that of sulindac, and of the structurally similar phospho-ibuprofen amide. We determined tear breakup time (TBUT) (tear stability), Schirmer's tear test (tear production), and by esthesiometry corneal sensitivity (symptoms). We also determined the biodistribution in the eye of topically applied PS. Results: PS in a solution formulation, given as eye drops q.i.d. was efficacious starting at a dose of 0.1%. The effect was apparent after 2 days of treatment and lasted at least 8 days after the last dose. Both signs (evidenced by TBUT and Schirmer's test) and symptoms (measured by corneal sensitivity) improved significantly. The best formulation was the solution formulation; a cyclodextrin-based formulation was also successful but the emulsion formulation was not. PS and its metabolites were essentially restricted to the anterior chamber of the eye. Sulindac and phospho-ibuprofen amide had no efficacy on DED. Conclusions: PS is efficacious against DED. Its effect, encompassing signs, and symptoms, are dose, formulation, and structure dependent. PS has therapeutic promise and merits further development.

Identification of Drug Candidates for Breast Cancer Therapy Through Scaffold Repurposing: A Brief Review

Conventional drug discovery is a time consuming and expensive expedition with less clinical preference achievement proportion intended for breast cancer therapy. Even if numerous novel approaches to the conformation of drugs have been introduced for breast cancer therapy, they are yet to be implemented in clinical practice. This tempting strategy facilitates a remarkable chance to take the entire benefit of existing drugs. Despite drug repurposing significantly decrease the investigational period and cost, it has got many objections and issues. Scaffold repurposing is an approach that procures a novel significance on the decrepit motto of "to commencement with a pristine drug" . Hence, we move into a probable and nearer approach, the exploitation of scaffolds, which was originally developed for other purposes, including anti-tumor activity. In this review, we summarize different drugs and scaffolds used in breast cancer therapy.

Arylpropionic acid-derived NSAIDs: New insights on derivatization, anticancer activity and potential mechanism of action

NSAIDs displayed chemopreventive and anticancer effects against several types of cancers. Moreover, combination of NSAIDs with anticancer agents resulted in enhanced anticancer activity. These findings have attracted much attention of researchers working in this field. The 2-arylpropionic acid-derived NSAIDs represent one of the most widely used anti-inflammatory agents. Additionally, they displayed antiproliferative activities against different types of cancer cells. Large volume of research was performed to identify molecular targets responsible for this activity. However, the exact mechanism underlying the anticancer activity of profens is still unclear. In this review article, the anticancer potential, structure activity relationship and synthesis of selected profen derivatives were summarized. This review is focused also on non-COX targets which can mediate the anticancer activity of this derivatives. The data in this review highlighted profens as promising lead compounds in future research to develop potent and safe anticancer agents.

Syntheses and cytotoxicity of phosphatidylcholines containing ibuprofen or naproxen moieties

In this study, novel phosphatidylcholines containing ibuprofen or naproxen moieties were synthesized in good yields and high purities. Under the given synthesis conditions, the attached drug moieties racemized, which resulted in the formation of phospholipid diastereomers. The comperative studies of the cytotoxicity of ibuprofen, naproxen and their phosphatidylcholine derivatives against human promyelocytic leukemia HL-60, human colon carcinoma Caco-2, and porcine epithelial intestinal IPEC-J2 cells were carried out. The results of these studies indicated that phospholipids with NSAIDs at both sn-1 and sn-2 positions (15 and 16) were more toxic than ibuprofen or naproxen themselves, whereas 2-lysophosphatidylcholines (7 and 8) were less toxic against all tested cell lines. Phospholipids with NSAIDs at sn-1 and palmitic acid at sn-2 (9 and 10) were also less toxic against Caco-2 and normal cells (IPEC-J2).

Phosphosulindac is efficacious in an improved concanavalin A-based rabbit model of chronic dry eye disease

Dry eye disease (DED) currently has no satisfactory treatment partly because of the lack of informative animal models. We evaluated the anti-inflammatory phosphosulindac (PS) for the treatment of DED using a new rabbit model of DED based on the concanavalin A (Con A) acute DED model: we injected all lacrimal glands with Con A weekly under ultrasound guidance, which prolonged DED to >3 weeks, and thoroughly assessed efficacy with tear break-up time (TBUT), tear osmolarity, Schirmer test, and tear lactoferrin levels. Rabbits with DED (n = 8-10 eyes per group) were treated topically with PS or vehicle 3×/day for 21days. PS restored TBUT, tear osmolarity, and lactoferrin levels (P < 0.0001-0.04) to normal but did not significantly improve the results of the Schirmer test. PS showed no side effects and was much more efficacious than cyclosporine or lifitegrast. In the cornea, PS suppressed the activation of nuclear factor kappa-B, the levels of transforming growth factor beta, interleukin-1 beta, interleukin-6, and interleukin-8, and the levels of matrix metalloproteinase (MMP)-1 and MMP-9, and MMP activity. Levels of prostaglandin E₂ (PGE₂) in tears and cornea were preserved in PS-treated rabbits. Ketorolac and diclofenac, two ophthalmic NSAIDs causing corneal melt, nearly completely suppressed PGE₂ levels but had no effect on MMPs. The effects of PS on PGE₂ and MMPs likely account for its apparent ocular safety. Our results establish an animal model for acute and chronic DED suitable for drug efficacy studies and indicate that PS merits evaluation for DED.

Wnt signaling in bone metastasis: mechanisms and therapeutic opportunities

Bone metastasis frequently occurs in advanced cancer patients, who will develop osteogenic/osteolytic bone lesions in the late stage of the disease. Wnt signaling pathway, which is mainly grouped into the β-catenin dependent pathway and β-catenin independent pathway, is a well-organized cascade that has been reported to play important roles in a variety of physiological and pathological conditions, including bone metastasis. Regulation of Wnt signaling in bone metastasis involves multiple stages, including dissemination of primary tumor cells to bone, dormancy and outgrowth of metastatic tumor cells, and tumor-induced osteogenic and osteolytic bone destruction, suggesting the importance of Wnt signaling in bone metastasis pathology. In this review, we will introduce the involvement of Wnt signaling components in specific bone metastasis stages and summarize the promising Wnt modulators that have shown potential as bone metastasis therapeutics, in the hope to maximize the therapeutic opportunities of Wnt signaling for bone metastasis.

Investigation of chronic efficacy and safety profile of two potential anti-inflammatory bipyrazole-based compounds in experimental animals

Purpose

Although nonsteroidal anti-inflammatory drugs are widely used to treat a variety of disorders, their administration is associated with gastrointestinal side effects, acute kidney injury and liver enzymes’ elevation. Accordingly, researchers are encouraged to create novel agents with better safety profile. The aim of the current study was to evaluate the chronic efficacy and safety profile of two compounds previously proven to have acceptable acute anti-inflammatory and analgesic activities.

Materials and methods

Doses were determined through formalin-induced mice paw edema-based dose–response curves. Granuloma weight was used to assess the chronic effect of the investigated compounds as compared to the vehicle and diclofenac representing the positive and the negative controls, respectively. Mice kidneys, livers and stomachs were histologically examined. Moreover, troponin I, alanine aminotransferase, aspartate aminotransferase, serum creatinine and blood urea nitrogen levels were measured.

Results

The results highlight that the granulomas and exudates developed in mice after 7 days of treatment, with compound I and compound II were significantly lower than that of the negative control group. Moreover, compound I showed significantly better anti-inflammatory effect than diclofenac. Troponin level was undetected in all groups. Histopathological examination of the stomach revealed normal mucosa for both tested compounds and controls. Likewise, kidneys showed neither significant histologic alteration nor biomarkers increase as compared to the control over both 7- and 30-day treatment periods. Mice that received the tested compounds or diclofenac exhibited transient liver damage specifically; congestion, vacuolization, necrosis and inflammation after 7 days of treatment which decreased significantly after 30 days of treatment as emphasized by the Suzuki score and biomarker levels.

Conclusion

Since the tested compounds, specifically compound I, presented a satisfactory chronic safety profile as well as anti-inflammatory effect, it is worth conducting further molecular pharmacological, toxicological and bioavailability studies to elucidate the efficacy of these potential anti-inflammatory bipyrazole compounds.

Therapeutic effect of acetazolamide, an aquaporin 1 inhibitor, on adjuvant-induced arthritis in rats by inhibiting NF-κB signal pathway

OBJECTIVES

Previous studies have shown that aquaporin 1 (AQP1) is up-regulated in synovium and cartilage of rheumatoid arthritis (RA) patients and that AQP1 may be involved in joint swelling and synovial inflammation. This study was aimed to investigate the potential therapeutic effect of acetazolamide (AZ, an AQP1 inhibitor) on rat adjuvant-induced arthritis (AIA) and explore its related mechanisms.

MATERIALS AND METHODS

Rat AIA was induced by complete Freund's adjuvant. The effect of AZ on rat AIA was evaluated by secondary hind paw swelling, arthritis index, TNF-α and IL-1β serum levels and histological examination of ankle joint. Proteoglycans expression and mRNA levels of type-II collagen (COII) and aggrecan in cartilage were measured by alcian blue staining and real-time PCR, respectively. The protein levels of AQP1, IκBα, phospho-IκBα (p-IκBα), NF-κB p65 and phospho-NF-κB p65 (p-NF-κB p65) in synovial tissues were detected by western blot.

RESULTS

AZ treatment could inhibit secondary hind paw swelling and arthritis index, reduce serum levels of TNF-α and IL-1β, and ameliorate pathological changes of ankle joint in AIA rats. AZ increased proteoglycans production and mRNA levels of COII and aggrecan in cartilage tissues. Moreover, AZ decreased AQP1 protein level and suppressed the activation of NF-κB pathway in synovium, indicated by inhibiting the degradation and phosphorylation of IκBα and reducing p-NF-κB p65 protein level.

CONCLUSIONS

AZ as an AQP1 inhibitor has a powerful therapeutic effect on rat AIA via inhibiting NF-κB activation, suggesting AQP1 inhibition might be of potential clinical interest in RA treatment.

Synthesis and Anticancer Activities of 4-[(Halophenyl)diazenyl]phenol and 4-[(Halophenyl)diazenyl]phenyl Aspirinate Derivatives against Nasopharyngeal Cancer Cell Lines

Aspirin and azo derivatives have been widely studied and have drawn considerable attention due to diverse biological activities. In this study, a series of 4-[(halophenyl)diazenyl]phenyl aspirinate derivatives were synthesized from the reaction of aspirin with 4-[(halophenyl)diazenyl]phenol via esterification, in the presence of DCC/DMAP in DCM with overall yield of 45–54%. 4-[(Halophenyl)diazenyl]phenol was prepared prior to esterification from coupling reaction of aniline derivatives and phenol in basic solution. All compounds were characterized using elemental analysis, FTIR, and 1H and 13C NMR spectroscopies. All compounds were screened for their anticancer activities against nasopharyngeal cancer (NPC) HK-1 cell lines and the viability of cultured cells was determined by MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxylmethoxylphenyl)-2-(4-sulfophenyl)-2H-tetrazolium]-based colorimetric assay. 4-[(E)-(Fluorophenyl)diazenyl]phenol showed the highest anticancer activity against NPC HK-1 cell lines compared to other synthesized compounds. 4-[(Halophenyl)diazenyl]phenyl aspirinate showed low cytotoxicity against NPC HK-1 cell lines compared to 4-[(halophenyl)diazenyl]phenol but better anticancer activity than aspirin alone.

Nonsteroidal Anti-Inflammatory Therapy: A Journey Toward Safety

The efficacy of nonsteroidal anti-inflammatory drugs (NSAIDs) against inflammation, pain, and fever has been supporting their worldwide use in the treatment of painful conditions and chronic inflammatory diseases until today. However, the long-term therapy with NSAIDs was soon associated with high incidences of adverse events in the gastrointestinal tract. Therefore, the search for novel drugs with improved safety has begun with COX-2 selective inhibitors (coxibs) being straightaway developed and commercialized. Nevertheless, the excitement has fast turned to disappointment when diverse coxibs were withdrawn from the market due to cardiovascular toxicity. Such events have once again triggered the emergence of different strategies to overcome NSAIDs toxicity. Here, an integrative review is provided to address the breakthroughs of two main approaches: (i) the association of NSAIDs with protective mediators and (ii) the design of novel compounds to target downstream and/or multiple enzymes of the arachidonic acid cascade. To date, just one phosphatidylcholine-associated NSAID has already been approved for commercialization. Nevertheless, the preclinical and clinical data obtained so far indicate that both strategies may improve the safety of nonsteroidal anti-inflammatory therapy.

Phospho-Aspirin (MDC-22) Prevents Pancreatic Carcinogenesis in Mice

Pancreatic cancer is a deadly disease with a dismal 5-year survival rate of <6%. The currently limited treatment options for pancreatic cancer underscore the need for novel chemopreventive and therapeutic agents. Accumulating evidence indicates that aspirin use is associated with a decreased risk of pancreatic cancer. However, the anticancer properties of aspirin are restricted by its gastrointestinal toxicity and its limited efficacy. Therefore, we developed phospho-aspirin (MDC-22), a novel derivative of aspirin, and evaluated its chemopreventive efficacy in preclinical models of pancreatic cancer. Phospho-aspirin inhibited the growth of human pancreatic cancer cell lines 8- to 12-fold more potently than aspirin; based on the 24-hour IC50 values. In a Panc-1 xenograft model, phospho-aspirin, at a dose of 100 mg/kg/d 5 times per week for 30 days, reduced tumor growth by 78% (P < 0.01 vs. vehicle control). Furthermore, phospho-aspirin prevented pancreatitis-accelerated acinar-to-ductal metaplasia in mice with activated Kras. In p48-Cre;Kras(G12D) mice, cerulein treatment (6 hourly injections two times per week for 3 weeks) led to a significant increase in ductal metaplasia, replacing the majority of the exocrine compartment. Administration of phospho-aspirin 100 mg/kg/day five times per week for 21 days (starting on the first day of cerulein injection) inhibited the acinar-to-ductal metaplasia, reducing it by 87% (P < 0.01, vs. cerulein-treated control). Phospho-aspirin appeared to be safe, with the animals showing no signs of toxicity during treatment. Mechanistically, phospho-aspirin inhibited EGFR activation in pancreatic cancer, an effect consistently observed in pancreatic cancer cells, primary acinar explants and in vivo In conclusion, our findings indicate that phospho-aspirin has strong anticancer efficacy in preclinical models of pancreatic cancer, warranting its further evaluation. Cancer Prev Res; 9(7); 624-34. ©2016 AACR.

Effects of anti-inflammatory drugs on intravenous immunoglobulin therapy in the acute phase of Kawasaki disease

This retrospective study aimed to investigate the effects of anti-inflammatory drugs (ADs) on intravenous immunoglobulin (IVIG) therapy in the acute phase of Kawasaki disease. In total, 182 pediatric patients who received IVIG therapy for Kawasaki disease between 1999 and 2013 at the Department of Pediatrics, Aomori Prefectural Central Hospital were enrolled. Patients were divided into 2 groups: an S group, including 111 patients who received single IVIG therapy with delayed administration of ADs, and a T group, including 71 patients who received concomitant AIDs with IVIG. During the study, the only ADs administered were aspirin (A: 30 mg/kg/day) or flurbiprofen (F: 3-5 mg/kg/day). Steroids were not administered to any patient. The regimen of the S group was partially used after 2004 and was used to all patients after 2009. The following clinical findings were significantly different between the S and T groups: disease onset before 2003 (0 vs. 59%, P < 0.001) and after 2009 (70 vs. 0%, P < 0.001), use of 2-g/kg/day IVIG therapy (100 vs. 93%, P = 0.034), ADs type (A/F: 62/49 vs. 17/54, P < 0.001), and the prevalence of coronary artery lesions (CAL) up to (1/111 vs. 11/71, P < 0.001) and after 30 days of illness (0/111 vs. 4/71, P = 0.022). Logistic regression analysis revealed that IVIG therapy only (S group; P = 0.009) and 2-g/kg/day IVIG therapy (P = 0.015) were significant factors for CAL suppression. The findings revealed a possible negative impact of ADs on initial IVIG therapy in the acute phase of Kawasaki disease. Initial single IVIG therapy with delayed administration of ADs may be useful to suppress CAL caused by Kawasaki disease.

Phospho-aspirin-2 (MDC-22) inhibits estrogen receptor positive breast cancer growth both in vitro and in vivo by a redox-dependent effect

Phospho-aspirin (PA-2) is a novel aspirin derivative that exhibits promising anticancer properties and is considerably safer than conventional aspirin. In this study, we investigated the chemotherapeutic efficacy of PA-2 in preclinical models of estrogen receptor positive (ER+) breast cancer and elucidated its mechanism of action. PA-2 inhibited the growth of ER+ cells more potently than aspirin in vitro, and exerted a triple cytokinetic effect that includes induction of apoptosis and cell cycle arrest as well as the inhibition of cell proliferation. PA-2 is highly efficacious in vivo, as treatment of established MCF7 xenografts with PA-2 induced tumor stasis (98.2% inhibition, p<0.01). PA-2 triggered the activation of p53-dependent apoptosis via two distinct mechanisms: 1) acetylation of p53 (at K373), which disrupts its interaction with its transcription repressor MDM2, and 2) translocation of p53 to the mitochondria leading to the dissipation of mitochondrial transmembrane potential (ΔΨ(m)). Consistent with these observations, both the RNAi-mediated knockdown of p53 and forced deactylation via HDAC1 over-expression attenuated the anticancer effect of PA-2 in MCF7 cells. An upstream mediator of the signaling effects of PA-2 is RONS. PA-2 induced oxidative stress in vitro and in mice bearing MCF7 xenografts; its induction effect appears to be tumor-specific. Crucially, administration of N-acetylcysteine, a ROS scavenger, abrogated the effect of PA-2 on p53 acetylation and mitochondria translocation, thus identifying RONS as proximal molecules mediating the anticancer effect of PA-2. In summary, our findings demonstrate that PA-2 is a promising antineoplastic compound against ER+ breast cancer, warranting further evaluation as an anticancer agent.

A novel Ras inhibitor (MDC-1016) reduces human pancreatic tumor growth in mice

Pancreatic cancer has one of the poorest prognoses among all cancers partly because of its persistent resistance to chemotherapy. The currently limited treatment options for pancreatic cancer underscore the need for more efficient agents. Because activating Kras mutations initiate and maintain pancreatic cancer, inhibition of this pathway should have a major therapeutic impact. We synthesized phospho-farnesylthiosalicylic acid (PFTS; MDC-1016) and evaluated its efficacy, safety, and metabolism in preclinical models of pancreatic cancer. PFTS inhibited the growth of human pancreatic cancer cells in culture in a concentration- and time-dependent manner. In an MIA PaCa-2 xenograft mouse model, PFTS at a dose of 50 and 100 mg/kg significantly reduced tumor growth by 62% and 65% (P < .05 vs vehicle control). Furthermore, PFTS prevented pancreatitis-accelerated acinar-to-ductal metaplasia in mice with activated Kras. PFTS appeared to be safe, with the animals showing no signs of toxicity during treatment. Following oral administration, PFTS was rapidly absorbed, metabolized to FTS and FTS glucuronide, and distributed through the blood to body organs. Mechanistically, PFTS inhibited Ras-GTP, the active form of Ras, both in vitro and in vivo, leading to the inhibition of downstream effector pathways c-RAF/mitogen-activated protein-extracellular signal-regulated kinase (ERK) kinase (MEK)/ERK1/2 kinase and phosphatidylinositol 3-kinase/AKT. In addition, PFTS proved to be a strong combination partner with phospho-valproic acid, a novel signal transducer and activator of transcription 3 (STAT3) inhibitor, displaying synergy in the inhibition of pancreatic cancer growth. In conclusion, PFTS, a direct Ras inhibitor, is an efficacious agent for the treatment of pancreatic cancer in preclinical models, deserving further evaluation.

Phospho-aspirin (MDC-22) inhibits breast cancer in preclinical animal models: an effect mediated by EGFR inhibition, p53 acetylation and oxidative stress

Background

The anticancer properties of aspirin are restricted by its gastrointestinal toxicity and its limited efficacy. Therefore, we synthesized phospho-aspirin (PA-2; MDC-22), a novel derivative of aspirin, and evaluated its chemotherapeutic and chemopreventive efficacy in preclinical models of triple negative breast cancer (TNBC).

Methods

Efficacy of PA-2 was evaluated in human breast cancer cells in vitro, and in orthotopic and subcutaneous TNBC xenografts in nude mice. Mechanistic studies were also carried out to elucidate the mechanism of action of PA-2.

Results

PA-2 inhibited the growth of TNBC cells in vitro more potently than aspirin. Treatment of established subcutaneous TNBC xenografts (MDA-MB-231 and BT-20) with PA-2 induced a strong growth inhibitory effect, resulting in tumor stasis (79% and 90% inhibition, respectively). PA-2, but not aspirin, significantly prevented the development of orthotopic MDA-MB-231 xenografts (62% inhibition). Mechanistically, PA-2: 1) inhibited the activation of epidermal growth factor receptor (EGFR) and suppressed its downstream signaling cascades, including PI3K/AKT/mTOR and STAT3; 2) induced acetylation of p53 at multiple lysine residues and enhanced its DNA binding activity, leading to cell cycle arrest; and 3) induced oxidative stress by suppressing the thioredoxin system, consequently inhibiting the activation of the redox sensitive transcription factor NF-κB. These molecular alterations were observed in vitro and in vivo, demonstrating their relevance to the anticancer effect of PA-2.

Conclusions

Our findings demonstrate that PA-2 possesses potent chemotherapeutic efficacy against TNBC, and is also effective in its chemoprevention, warranting further evaluation as an anticancer agent.

Binary graft modification of polypropylene for anti-inflammatory drug-device combo products

Temperature- and pH-responsive copolymers were γ-ray grafted onto polypropylene (PP) to provide its surface with capability to load and to control the release of nonsteroidal anti-inflammatory drugs (NSAIDs) with the aim of being useful as component of drug-eluting medical devices. Poly(N,N'-dimethylaminoethylmethacrylate) (PDMAEMA) or poly(4-vinylpyridine) (P4VP) were grafted onto PP films via a direct method, and then poly(N-isopropylacrylamide) (PNIPAAm) was grafted applying a preirradiation method. The binary graft copolymers showed hemocompatibility and certain capability to adsorb albumin. (PP-g-DMAEMA)-g-NIPAAm exhibited higher affinity for ibuprofen and, particularly, diclofenac than (PP-g-4VP)-g-NIPAAm. Sustained release was observed under physiological conditions. Cytotoxicity and anti-inflammatory activity of NSAID-eluting (PP-g-DMAEMA)-g-NIPAAm films were evaluated on RAW 264.7 macrophage cells. First, dose dependence of anti-inflammatory activity and cytotoxicity of ibuprofen and diclofenac on RAW 264.7 cells were investigated to elucidate the ranges of drug concentration that the graft copolymers should provide. Optimal concentrations of diclofenac and ibuprofen at which they reduce inflammation while maintaining cell viability were determined to be 200 μg/mL and above 400 μg/mL in culture medium. Sequential grafting of DMAEMA and NIPAAm made PP surface to exhibit remarkably high affinity to diclofenac, being able to load and to regulate drug release fulfilling in vitro requirements to avoid inflammatory response.

Topically applied phospho-sulindac hydrogel is efficacious and safe in the treatment of experimental arthritis in rats

PURPOSE

Formulate phospho-sulindac (P-S, OXT-328) in a Pluronic hydrogel to be used as a topical anti-inflammatory agent and study its efficacy, safety and pharmacokinetics in an arthritis model.

METHODS

LEW/crlBR rats with Freund's adjuvant-induced arthritis were treated with P-S formulated in Pluronic hydrogel (PSH). We determined the clinical manifestations of arthritis including the locomotor activity of the rats; evaluated joints for inflammation, bone resorption, cartilage damage, COX-2 expression and NF-κB activation; assayed plasma IL-6 and IL-10 levels; and studied the pharmacokinetics of P-S in rats after topical or oral administration.

RESULTS

PSH applied at the onset of arthritis or when arthritis was fully developed, suppressed it by 56-82%, improved the locomotor activity of the rats 2.1-4.4 fold, suppressed synovial inflammation, bone resorption, cartilage damage, NF-κB activation and COX-2 expression but not plasma IL-6 and IL-10 levels. There were no side effects. PSH produced rapidly high local levels of P-S with <14% of P-S reaching the circulation, while orally administered P-S was rapidly metabolized generating much lower joint levels of P-S.

CONCLUSIONS

Topical application of PSH is efficacious and safe in the treatment of Freund's adjuvant-induced arthritis; has a favorable pharmacokinetic profile; and likely acts by suppressing key pro-inflammatory signaling pathways.

Phosphosulindac (OXT-328) selectively targets breast cancer stem cells in vitro and in human breast cancer xenografts

Pharmacological targeting of breast cancer stem cells (CSCs) is highly promising for the treatment of breast cancer, as the small population of CSCs appears responsible for tumor initiation and progression and also for resistance to conventional treatment. Here we report that the novel phosphosulindac (OXT-328, PS) selectively and effectively eliminates breast CSCs both in vitro and in vivo. PS reduced cell proliferation and induced apoptosis in various breast CSCs. Breast CSCs are resistant to conventional cancer drugs but are sensitive to PS. Long-term treatment of mixtures of cultured breast CSCs and breast cancer cells with PS preferentially eliminated the CSCs. PS impaired the ability of CSCs to form mammospheres and markedly suppressed the expression of CSC-related genes. More importantly, PS prevented by half (p = .06) the formation of tumors initiated by CSCs in immunodeficient mice, and inhibited by 83% (p < .05) the growth of already formed breast cancer xenografts, reducing the proportion of CSCs in them. PS suppressed the Wnt/β-catenin pathway by stimulating the degradation of β-catenin and its relocalization to the cell membrane and also blocked the epithelial-mesenchymal transition and the generation of breast CSCs. These results indicate that PS has a strong inhibitory effect against breast cancer, acting, at least in part, by targeting CSCs through a signaling mechanism involving Wnt signaling.

The anticancer effect of phospho-tyrosol-indomethacin (MPI-621), a novel phosphoderivative of indomethacin: in vitro and in vivo studies

We have synthesized a novel derivative of indomethacin, phospho-tyrosol-indomethacin (PTI; MPI-621), and evaluated its anticancer efficacy in vitro and in vivo. PTI inhibited the growth of human colon, breast and lung cancer cell lines 6-30-fold more potently than indomethacin. In vivo, in contrast to indomethacin that was unable to inhibit colon cancer xenograft growth, PTI inhibited the growth of colon (69% at 10mg/kg/day, P < 0.01) and lung (91% at 15mg/kg/day, P < 0.01) subcutaneous cancer xenografts in immunodeficient mice, suppressing cell proliferation by 33% and inducing apoptosis by 75% (P < 0.05, for both). Regarding its pharmacokinetics in mice, after a single intraperitoneal injection of PTI, its plasma levels reached the maximum concentration (Cmax = 46 μM) at 2h (Tmax) and became undetectable at 4h. Indomethacin is the major metabolite of PTI, with plasma Cmax = 378 μM and Tmax = 2.5h; it became undetectable 24h postadministration. The cellular uptake of PTI (50-200 μM) at 6h was about 200-fold greater than that of indomethacin. Regarding its safety, PTI had no significant genotoxicity, showed less gastrointestinal toxicity than indomethacin and presented no cardiac toxicity. Mechanistically, PTI suppressed prostaglandin E2 production in A549 human lung cancer cells and strongly inhibited nuclear factor-κB activation in A549 xenografts. These findings indicate that PTI merits further evaluation as an anticancer agent.

Regioselective oxidation of phospho-NSAIDs by human cytochrome P450 and flavin monooxygenase isoforms: implications for their pharmacokinetic properties and safety

BACKGROUND AND PURPOSE

Phospho-ibuprofen (MDC-917) and phospho-sulindac (OXT-328) are highly effective in cancer and arthritis treatment in preclinical models. Here, we investigated their metabolism by major human cytochrome P450s (CYPs) and flavin monooxygenases (FMOs).

EXPERIMENTAL APPROACH

The CYP/FMO-catalysed metabolism of phospho-ibuprofen and phospho-sulindac was studied by using in silico prediction modelling and a direct experimental approach.

KEY RESULTS

The CYP isoforms catalyse the oxidation of non-steroidal anti-inflammatory drugs (NSAIDs) and phospho-NSAIDs, with distinct activity and regioselectivity. CYP1A2, 2C19, 2D6 and 3A4 oxidize phospho-ibuprofen, but not ibuprofen; whereas CYP2C9 oxidizes ibuprofen, but not phospho-ibuprofen. All CYPs tested oxidize phospho-sulindac, but not sulindac. Among the five CYPs evaluated, CYP3A4 and 2D6 are the most active in the oxidation of phospho-ibuprofen and phospho-sulindac respectively. FMOs oxidized phospho-sulindac and sulindac, but not phospho-ibuprofen or ibuprofen. FMOs were more active towards phospho-sulindac than sulindac, indicating that phospho-sulindac is a preferred substrate of FMOs. The susceptibility of phospho-NSAIDs to CYP/FMO-mediated metabolism was also reflected in their rapid oxidation by human and mouse liver microsomes, which contain a full complement of CYPs and FMOs. Compared with conventional NSAIDs, the higher activity of CYPs towards phospho-ibuprofen and phospho-sulindac may be due to their greater lipophilicity, a key parameter for CYP binding.

CONCLUSIONS AND IMPLICATIONS

CYPs and FMOs play an important role in the metabolism of phospho-NSAIDs, resulting in differential pharmacokinetic profiles between phospho-NSAIDs and NSAIDs in vivo. The consequently more rapid detoxification of phospho-NSAIDs is likely to contribute to their greater safety.

A novel NSAID derivative, phospho-ibuprofen, prevents AOM-induced colon cancer in rats

The cancer chemopreventive properties and gastrointestinal toxicity of ibuprofen are well documented. Modification of existing NSAIDs has improved on the chemopreventive efficacy of this agent and reduced its toxicity. In this study, ibuprofen and a modified derivative (phospho-modified ibuprofen or p-ibuprofen) were used in a chemically induced model of colon cancer. Fisher 344 rats were injected with azoxymethane then treated with either ibuprofen (500 ppm) or p-ibuprofen (900 ppm) for 20 weeks to observe aberrant crypt foci (ACF) or 40 weeks to evaluate tumor incidence and multiplicity. β-catenin and p65 were measured in colonic tissues by immunofluorescence staining. Equal molar doses of ibuprofen (75 and 670 mg/kg) and p-ibuprofen (135 and 1,215 mg/kg) were administered to rats for 7 days to assess acute toxicity. The in vitro effect of p-ibuprofen on COX-2 and PGE(2) synthesis, β-catenin expression and NF-κB activity were examined in RAW 264.7 macrophage and HCT 116 colon cancer cells. At week 20, p-ibuprofen and ibuprofen significantly reduced the multiplicity of ACF compared with control (p<0.05); 31.2 and 37.9%, respectively. At week 40, p-ibuprofen and ibuprofen reduced the multiplicity of colon tumors compared with control (p<0.01) by 47.2 and 56.6%, respectively. Equal molar concentrations of ibuprofen (670 mg/kg) and p-ibuprofen (1,215 mg/kg) resulted in stomach ulceration in 85.7% (6 out of 7) and 14.3% (1 out of 7) of rats, respectively, with p<0.01. Immunofluoresence staining and western blot analysis demonstrated that both ibuprofen and p-ibuprofen suppressed β-catenin nuclear translocation in colon cancer cells. In addition, p-ibuprofen but not ibuprofen inhibited NF-κB activation in colon cancer cells. Collectively, these results suggest that p-ibuprofen is a potential effective novel drug for long-term use in colon cancer prevention.

Prodrugs of nonsteroidal anti-inflammatory drugs (NSAIDs), more than meets the eye: a critical review

The design and the synthesis of prodrugs for nonsteroidal anti-inflammatory drugs (NSAIDs) have been given much attention by medicinal chemists, especially in the last decade. As a therapeutic group, NSAIDs are among the most widely used prescribed and over the counter (OTC) medications. The rich literature about potential NSAID prodrugs clearly shows a shift from alkyl, aryalkyl or aryl esters with the sole role of masking the carboxylic acid group, to more elaborate conjugates that contain carefully chosen groups to serve specific purposes, such as enhancement of water solubility and dissolution, nitric oxide release, hydrogen sulfide release, antioxidant activity, anticholinergic and acetylcholinesterase inhibitory (AChEI) activity and site-specific targeting and delivery. This review will focus on NSAID prodrugs that have been designed or were, later, found to possess intrinsic pharmacological activity as an intact chemical entity. Such intrinsic activity might augment the anti-inflammatory activity of the NSAID, reduce its side effects or transform the potential therapeutic use from classical anti-inflammatory action to something else. Reports discussed in this review will be those of NO-NSAIDs, anticholinergic and AChEI-NSAIDs, Phospho-NSAIDs and some miscellaneous agents. In most cases, this review will cover literature dealing with these NSAID prodrugs from the year 2006 and later. Older literature will be used when necessary, e.g., to explain the chemical and biological mechanisms of action.

Phospho-ibuprofen (MDC-917) incorporated in nanocarriers: anti-cancer activity in vitro and in vivo

BACKGROUND AND PURPOSE

Phospho-ibuprofen (P-I; MDC-917) inhibits the growth of colon cancer in mice. Here, we investigated the use of nanocarriers to improve its pharmacokinetics (PKs) and anti tumour efficacy.

EXPERIMENTAL APPROACH

The cellular uptake and cytotoxicity of P-I encapsulated into liposomes and micelles, and its in vitro metabolic stability, were determined in cultures of human colon adenocarcinoma cells. The performance of liposomal P-I was further evaluated in PK studies in mice, and in a model of colon cancer xenografts in nude mice.

KEY RESULTS

Liposomal P-I and micellar P-I showed significantly enhanced cellular uptake in the colon cancer cells. Liposomal P-I also demonstrated increased cytotoxicity in vitro. Free P-I was metabolized rapidly to ibuprofen in the presence of purified esterases. In contrast, liposomal P-I, and to a lesser extent micellar P-I, was resistant to esterase-mediated hydrolysis. In mice, liposomal P-I partially protected P-I from hydrolysis in the circulation, and improved the biodistribution of intact P-I and its metabolites compared to free P-I. Liposomal P-I was more effective at inhibiting the growth of human colon cancer xenografts in mice, which may be explained on the basis of its improved PK profile compared to free P-I.

CONCLUSIONS AND IMPLICATIONS

Liposome encapsulation of P-I partially protected P-I from esterase-mediated hydrolysis in mice, enhanced the cytotoxicity and bioavailability of P-I and increased its efficacy at inhibiting the growth of human colon cancer xenografts. These results indicate that liposomes are suitable nanocarriers for the delivery of P-I, and that the anti-tumour potential of liposomal P-I merits further evaluation.

Topical phospho-sulindac (OXT-328) is effective in the treatment of non-melanoma skin cancer

Phospho-sulindac (P-S, OXT-328), a novel sulindac derivative, has shown superior anticancer efficacy and safety compared to sulindac. In this study, we investigated the efficacy of topical P-S hydrogel in the treatment of non-melanoma skin cancer in preclinical models. P-S is a potent inhibitor of A431 epidermoid carcinoma in vitro and achieves this effect by inhibiting cell proliferation and inducing apoptosis. The anticancer efficacy of topical and oral P-S was further evaluated in mice bearing A431 intradermal xenografts. Compared to the controls, topical P-S hydrogel inhibited the A431 xenografts by 70.5% (p<0.01), while oral P-S inhibited it by 43.4% (p<0.05), being significantly less effective than topical P-S (p= 0.017). Topical P-S hydrogel generated significant levels (>500 nmol/g tumor tissue) of intact P-S in the tumors, accounting for 92.5% of the total metabolites in the A431 xenografts. This local delivery of high levels of intact P-S to the A431 xenografts is an important contributor to the potent activity of topical P-S and no local or systemic side effects were noted in the treatment group. Thus, topical P-S is a promising treatment modality against non-melanoma skin cancer and merits further evaluation.

In vitro and in vivo metabolic studies of phospho-aspirin (MDC-22)

PURPOSE

To investigate the metabolism of phospho-aspirin (PA, MDC-22), a novel anti-cancer and anti-inflammatory agent.

METHODS

The metabolism of PA was studied in the liver and intestinal microsomes from mouse, rat and human.

RESULTS

PA is rapidly deacetylated to phospho-salicylic acid (PSA), which undergoes regioselective oxidation to generate 3-OH-PSA and 5-OH-PSA. PSA also can be hydrolyzed to give salicylic acid (SA), which can be further glucuronidated. PA is far more stable in human liver or intestinal microsomes compared to those from mouse or rat due to its slowest deacetylation in human microsomes. Of the five major human cytochrome P450 (CYP) isoforms, CYP2C19 and 2D6 are the most active towards PSA. In contrast to PSA, conventional SA is not appreciably oxidized by the CYPs and liver microsomes, indicating that PSA is a preferred substrate of CYPs. Similarly, PA, in contrast to PSA, cannot be directly oxidized by CYPs and liver microsomes, indicating that the acetyl group of PA abrogates its oxidation by CYPs.

CONCLUSIONS

Our findings establish the metabolism of PA, reveal significant inter-species differences in its metabolic transformations, and provide an insight into the role of CYPs in these processes.

Phospho-sulindac (OXT-328) inhibits the growth of human lung cancer xenografts in mice: enhanced efficacy and mitochondria targeting by its formulation in solid lipid nanoparticles

PURPOSE

To evaluate the antitumor efficacy of solid lipid nanoparticle-encapsulated phospho-sulindac (SLN-PS) in human lung cancer.

METHODS

PS was incorporated into SLNs using the emulsion evaporation technique. We determined the antitumor activity of SLN-PS in cultured lung cancer cells. The performance of SLN-PS was further evaluated by pharmacokinetic studies in mice and in a model of human lung cancer xenografts in nude mice.

RESULTS

SLN-PS was >4-fold more potent than PS in inhibiting the growth of A549 and H510 cells in vitro. SLN-PS enhanced cellular uptake and facilitated PS accumulation in mitochondria, leading to oxidative stress and apoptosis via the mitochondrial-apoptosis pathway. SLN-PS was highly effective in suppressing the growth of A549 xenografts (78% inhibition compared to control, p < 0.01); while PS had no significant effect. Formulation of PS in SLNs resulted in improved pharmacokinetics in mice and an enhanced (≈ 14-fold) accumulation of PS and its metabolites in A549 xenografts. Finally, SLN-PS enhanced urinary F2-isoprostane uniquely in mice bearing A549 xenografts compared to untreated controls, suggesting that SLN-PS specifically induced oxidative stress in tumors.

CONCLUSIONS

Our results show that SLN-PS is efficacious in suppressing the growth of lung cancer and merits further evaluation.

The metabolism and pharmacokinetics of phospho-sulindac (OXT-328) and the effect of difluoromethylornithine

BACKGROUND AND PURPOSE

Phospho-sulindac (PS; OXT-328) prevents colon cancer in mice, especially when combined with difluoromethylornithine (DFMO). Here, we explored its metabolism and pharmacokinetics.

EXPERIMENTAL APPROACH

PS metabolism was studied in cultured cells, liver microsomes and cytosol, intestinal microsomes and in mice. Pharmacokinetics and biodistribution of PS were studied in mice.

KEY RESULTS

PS undergoes reduction and oxidation yielding PS sulphide and PS sulphone; is hydrolysed releasing sulindac, which generates sulindac sulphide (SSide) and sulindac sulphone (SSone), all of which are glucuronidated. Liver and intestinal microsomes metabolized PS extensively but cultured cells converted only 10% of it to PS sulphide and PS sulphone. In mice, oral PS is rapidly absorbed, metabolized and distributed to the blood and other tissues. PS survives only partially intact in blood; of its three major metabolites (sulindac, SSide and SSone), sulindac has the highest C(max) and SSone the highest t(1/2) ; their AUC(0-24h) are similar. Compared with conventional sulindac, PS generated more SSone but less SSide, which may contribute to the safety of PS. In the gastroduodenal wall of mice, 71% of PS was intact; sulindac, SSide and SSone together accounted for <30% of the total. This finding may explain the lack of gastrointestinal toxicity by PS. DFMO had no effect on PS metabolism but significantly reduced drug level in mouse plasma and other tissues.

CONCLUSIONS AND IMPLICATIONS

Our findings establish the metabolism of PS define its pharmacokinetics and biodistribution, describe its interactions with DFMO and largely explain its gastrointestinal safety.

Phospho-ibuprofen (MDC-917) suppresses breast cancer growth: an effect controlled by the thioredoxin system

Introduction

We have recently synthesized phospho-ibuprofen (P-I; MDC-917), a safer derivative of ibuprofen, which has shown anti-cancer activity. We investigated its efficacy and mechanism of action in the treatment of breast cancer in preclinical models.

Methods

We evaluated the anti-breast-cancer efficacy of P-I alone or incorporated into liposomes (Lipo-P-I) in human estrogen receptor-positive (MCF-7) and triple-negative, i.e., estrogen receptor-negative, progesterone receptor-negative and HER2-negative (MDA-MB231) breast cancer cell lines - as they represent the most frequent (estrogen receptor-positive) and the most difficult-to-treat (triple-negative) subtypes of breast cancer - and their xenografts in nude mice. We assessed the effect of P-I on the levels of reactive oxygen nitrogen species in response to P-I using molecular probes, on the thioredoxin system (expression and redox status of thioredoxin-1 (Trx-1) and thioredoxin reductase activity), on cyclooxygenase 2, NF-κB and mitogen-activated protein kinase cell signaling; and on the growth of xenografts with stably knocked-down Trx-1.

Results

Compared with controls, P-I 400 mg/kg/day inhibited the growth of MDA-MB231 xenografts by 266%, while the growth of MCF-7 xenografts was inhibited 51% byP-I 300 mg/kg/day and 181% by Lipo-P-I 300 mg/kg/day. In both cell lines, P-I induced oxidative stress and suppressed the thioredoxin system (oxidized Trx-1 and decreased its expression; inhibited thioredoxin reductase activity). These changes triggered downstream redox signaling: the activity of NF-κB was suppressed and the Trx-1-ASK1 complex was dissociated, activating the p38 and JNK mitogen-activated protein kinase cascades. Trx-1 knockdown abrogated the anti-cancer effect of P-I in vitro and in vivo.

Conclusion

P-I is safe and effective against breast cancer. Liposomal formulation enhances its efficacy; the effect is heavily dependent on the induction of oxidative stress and the suppression of the thioredoxin system. P-I merits further evaluation as an agent for the treatment of breast cancer.

Chemotherapeutic properties of phospho-nonsteroidal anti-inflammatory drugs, a new class of anticancer compounds

Nonsteroidal anti-inflammatory drugs (NSAID) exhibit antineoplastic properties, but conventional NSAIDs do not fully meet safety and efficacy criteria for use as anticancer agents. In this study, we evaluated the chemotherapeutic efficacy of 5 novel phospho-NSAIDs, each of which includes in addition to the NSAID moiety a diethylphosphate linked through a butane moiety. All 5 compounds inhibited the growth of human breast, colon, and pancreatic cancer cell lines with micromolar potency. In vivo investigations confirmed the antitumor activity of phospho-aspirin (PA) and phospho-sulindac (PS) in inhibiting tumor growth in established human xenograft models, in which cell proliferation was suppressed and apoptosis enhanced in the absence of detectable animal toxicity. Notably, all of the phospho-NSAIDs tested induced reactive oxygen and nitrogen species in cultured cells, with PA and PS inducing detectable levels of oxidative stress in vivo that were associated positively with apoptosis and negatively with proliferation. Potentially explaining these effects, all of the phospho-NSAIDs tested also inhibited the thioredoxin system and the redox sensitive transcription factor NF-κB. Taken together, our findings show the strong anticancer efficacy and promising safety of phospho-NSAIDs in preclinical models of breast, colon, and pancreatic cancer, suggesting further evaluation as anticancer agents.

Carboxylesterases 1 and 2 hydrolyze phospho-nonsteroidal anti-inflammatory drugs: relevance to their pharmacological activity

Phospho-nonsteroidal anti-inflammatory drugs (phospho-NSAIDs) are novel NSAID derivatives with improved anticancer activity and reduced side effects in preclinical models. Here, we studied the metabolism of phospho-NSAIDs by carboxylesterases and assessed the impact of carboxylesterases on the anticancer activity of phospho-NSAIDs in vitro and in vivo. The expression of human liver carboxylesterase (CES1) and intestinal carboxylesterase (CES2) in human embryonic kidney 293 cells resulted in the rapid intracellular hydrolysis of phospho-NSAIDs. Kinetic analysis revealed that CES1 is more active in the hydrolysis of phospho-sulindac, phospho-ibuprofen, phospho-naproxen, phospho-indomethacin, and phospho-tyrosol-indomethacin that possessed a bulky acyl moiety, whereas the phospho-aspirins are preferentially hydrolyzed by CES2. Carboxylesterase expression leads to a significant attenuation of the in vitro cytotoxicity of phospho-NSAIDs, suggesting that the integrity of the drug is critical for anticancer activity. Benzil and bis-p-nitrophenyl phosphate (BNPP), two carboxylesterase inhibitors, abrogated the effect of carboxylesterases and resensitized carboxylesterase-expressing cells to the potent cytotoxic effects of phospho-NSAIDs. In mice, coadministration of phospho-sulindac and BNPP partially protected the former from esterase-mediated hydrolysis, and this combination more effectively inhibited the growth of AGS human gastric xenografts in nude mice (57%) compared with phospho-sulindac alone (28%) (p = 0.037). Our results show that carboxylesterase mediates that metabolic inactivation of phospho-NSAIDs, and the inhibition of carboxylesterases improves the efficacy of phospho-NSAIDs in vitro and in vivo.

Sterically stabilized liposomes incorporating the novel anticancer agent phospho-ibuprofen (MDC-917): preparation, characterization, and in vitro/in vivo evaluation

PURPOSE

To incorporate phospho-ibuprofen (P-I), a lipophilic, water insoluble novel anti-cancer agent, into pegylated liposomes and upon formulation optimization to evaluate its antitumor activity in vitro and in vivo.

METHODS

P-I loaded liposomes were prepared using the thin-film hydration method, and characterized for size, zeta potential, drug content and drug release. We examined their physical stability by particle size changes; their lyophilization ability in the presence of cryoprotectants; and their antitumor activity in vitro in human cancer cell lines and in vivo in a xenograft murine model.

RESULTS

P-I was successfully loaded into liposomes consisting of soy-PC and PEG(2000)-PE. These liposomes were <150 nm in diameter; exhibited prolonged stability in suspension and can be lyophilized using sucrose as cryoprotectant. P-I liposomes inhibited the growth of human cancer cell lines in vitro and in vivo of xenograft in nude mice to a greater extent than free P-I.

CONCLUSIONS

High levels of P-I can be incorporated into liposomes which can be lyophilized in the presence of sucrose and showed good stability upon storage. Moreover, these drug-incorporating liposomes were capable of inhibiting the growth of xenografted tumors in mice more effectively than free P-I. These results justify further development of the P-I liposomes.

Phospho-sulindac (OXT-328) combined with difluoromethylornithine prevents colon cancer in mice

The nonsteroidal anti-inflammatory drug (NSAID) sulindac and the ornithine decarboxylase (ODC) antagonist difluoromethylornithine (DFMO), individually and together, are effective inhibitors of colon carcinogenesis. However, chronic use of sulindac is associated with significant side effects. We evaluated the chemopreventive efficacy of phospho-sulindac (P-S, OXT-328), an apparently safe derivative of sulindac, together with DFMO, in HT-29 human colon cancer xenografts. Nude mice were divided into four groups as follows: group 1 received vehicle (corn oil); group 2 received P-S (100 mg/kg/d) by oral gavage; group 3 received DFMO (2% in drinking water); and group 4 received P-S (100 mg/kg/d) by gavage plus DFMO (2% in drinking water; P-S/DFMO). Eighteen days after implantation, compared with controls, tumor volume was inhibited 65.9% by P-S, 52.9% by DFMO, and 70.9% by P-S/DFMO (P < 0.01 for all). P-S/DFMO reduced cell proliferation 27.1% and increased apoptosis 38.9% compared with controls (P < 0.05 for both). Compared with controls, P-S reduced the levels of thioredoxin-1 (Trx-1) and thioredoxin reductase (TrxR), whereas DFMO reduced polyamine content (putrescine and spermidine) and TrxR levels. Importantly, P-S/DFMO decreased putrescine and spermidine levels and the expression of Trx-1, TrxR, and cyclooxygenase (COX) 2. Of these molecular targets, TrxR most consistently correlated with tumor growth. Study results show that P-S/DFMO is an efficacious drug combination for colon cancer prevention and also show the safety of P-S, which may overcome the limiting side effects of conventional sulindac. P-S/DFMO has an intricate mechanism of action extending beyond polyamines and including the thioredoxin system, an emerging regulator of chemoprevention. P-S/DFMO merits further evaluation.

Phospho-ibuprofen (MDC-917) is a novel agent against colon cancer: efficacy, metabolism, and pharmacokinetics in mouse models

We have developed a novel chemical modification of conventional nonsteroidal anti-inflammatory drugs to reduce their toxicity and enhance their efficacy. Phospho-ibuprofen [(PI) 2-(4-isobutyl-phenyl)-propionic acid-4-(diethoxy-phosphoryloxy)-butyl ester (MDC-917)], a novel derivative of ibuprofen, strongly inhibited the growth of human colon cancer cells in vitro and SW480 human colon cancer xenografts in nude mice. PI was metabolized minimally by cultured cells, but extensively by liver microsomes and mice, undergoing regioselective oxidation to produce 1-OH-PI and carboxyl-PI, which can be hydrolyzed to 1-OH-ibuprofen and carboxyl-ibuprofen, respectively. PI also can be hydrolyzed to release ibuprofen, which can generate 2-OH-ibuprofen, carboxyl-ibuprofen, and ibuprofen glucuronide. After a single oral administration (400 mg/kg) of PI, ibuprofen and ibuprofen glucuronide are the main plasma metabolites of PI; they have, respectively, C(max) of 530 and 215 μM, T(max) of 1 and 2 h, elimination t(1/2) of 7.7 and 5.3 h, and area under the concentration-time curve (0-24 h) of 1816 and 832 μM × h. Intact PI was detected in several tissues but not in plasma; at a higher PI dose (1200 mg/kg), PI plasma levels were 12.4 μM. PI generated the same metabolites in mouse plasma as conventional ibuprofen, but with much lower levels, perhaps accounting for the enhanced safety of PI. The antitumor effect of PI was significantly associated with plasma ibuprofen levels (p = 0.016) but not with xenograft ibuprofen levels (p = 0.08), suggesting a complex anticancer effect. These results provide a pharmacological basis to explain, at least in part, the anticancer efficacy and safety of this promising compound and indicate that PI merits further evaluation as an anticancer agent.