Efficient NQO1 substrates are potent and selective anticancer agents

A major goal of personalized medicine in oncology is the identification of drugs with predictable efficacy based on a specific trait of the cancer cell, as has been demonstrated with gleevec (presence of Bcr-Abl protein), herceptin (Her2 overexpression), and iressa (presence of a specific EGFR mutation). This is a challenging task, as it requires identifying a cellular component that is altered in cancer, but not normal cells, and discovering a compound that specifically interacts with it. The enzyme NQO1 is a potential target for personalized medicine, as it is overexpressed in many solid tumors. In normal cells NQO1 is inducibly expressed, and its major role is to detoxify quinones via bioreduction; however, certain quinones become more toxic after reduction by NQO1, and these compounds have potential as selective anticancer agents. Several quinones of this type have been reported, including mitomycin C, RH1, EO9, streptonigrin, β-lapachone, and deoxynyboquinone (DNQ). However, no unified picture has emerged from these studies, and the key question regarding the relationship between NQO1 processing and anticancer activity remains unanswered. Here, we directly compare these quinones as substrates for NQO1 in vitro, and for their ability to kill cancer cells in culture in an NQO1-dependent manner. We show that DNQ is a superior NQO1 substrate, and we use computationally guided design to create DNQ analogues that have a spectrum of activities with NQO1. Assessment of these compounds definitively establishes a strong relationship between in vitro NQO1 processing and induction of cancer cell death and suggests these compounds are outstanding candidates for selective anticancer therapy.

An NQO1 substrate with potent antitumor activity that selectively kills by PARP1-induced programmed necrosis

Agents, such as β-lapachone, that target the redox enzyme, NAD(P)H:quinone oxidoreductase 1 (NQO1), to induce programmed necrosis in solid tumors have shown great promise, but more potent tumor-selective compounds are needed. Here, we report that deoxynyboquinone kills a wide spectrum of cancer cells in an NQO1-dependent manner with greater potency than β-lapachone. Deoxynyboquinone lethality relies on NQO1-dependent futile redox cycling that consumes oxygen and generates extensive reactive oxygen species (ROS). Elevated ROS levels cause extensive DNA lesions, PARP1 hyperactivation, and severe NAD+ /ATP depletion that stimulate Ca2+ -dependent programmed necrosis, unique to this new class of NQO1 "bioactivated" drugs. Short-term exposure of NQO1+ cells to deoxynyboquinone was sufficient to trigger cell death, although genetically matched NQO1- cells were unaffected. Moreover, siRNA-mediated NQO1 or PARP1 knockdown spared NQO1+ cells from short-term lethality. Pretreatment of cells with BAPTA-AM (a cytosolic Ca2+ chelator) or catalase (enzymatic H2O2 scavenger) was sufficient to rescue deoxynyboquinone-induced lethality, as noted with β-lapachone. Investigations in vivo showed equivalent antitumor efficacy of deoxynyboquinone to β-lapachone, but at a 6-fold greater potency. PARP1 hyperactivation and dramatic ATP loss were noted in the tumor, but not in the associated normal lung tissue. Our findings offer preclinical proof-of-concept for deoxynyboquinone as a potent chemotherapeutic agent for treatment of a wide spectrum of therapeutically challenging solid tumors, such as pancreatic and lung cancers.

Synthesis and Optical Properties of Bifunctional Thiophene Molecules Coordinated to Ruthenium

A series of unsymmetrical bi- and tetrathiophenes have been synthesized with bipyridine and phosphonic acid functional groups. To do this, phosphonic esters were bonded to thiophenes and the thiophenes coupled to bipyridine. After synthesis of the thienylbipyridines, bis(bipyridine) ruthenium was coordinated to them through the bipyridines. The thienylbipyridines absorb visible light and fluoresce; however, on attachment to ruthenium, both their fluorescence and that of ruthenium are quenched. An additional effect of coordinating ruthenium to the thiophenes is a new absorption band around 470 nm. Variation in oligothiophene length and bipyridine substitution position allowed comparison of the effect of these variables on electronic properties. The longer oligothiophenes display lower-energy absorptions and emissions than that of the shorter thiophenes. In contrast, the position of the bipyridine attachment does not have a large effect on the absorbance or emission wavelength, or on the fluorescence quantum yield.

Trabeculectomy with multiple applications of mitomycin-C in monkeys with experimental glaucoma

To inhibit the wound healing process and to achieve a better intraocular pressure lowering effect, we applied mitomycin-C (MMC) topically in trabeculectomy at different time sequences. In this experiment, a model of glaucoma trabeculectomy combined with light microscopic autoradiography study was used to evaluate the clinical and histological effects and the time course of cellular incorporation of tritiated thymidine. This study utilized twelve eyes (divided into three groups) of six monkeys with experimental glaucoma. Group I received 0.08 ml subconjunctival injection of 0.02 mg/ml MMC 24 to 36 hours prior to trabeculectomy. Group II received intraoperative topical application of 0.27 mg/ml MMC for 4 minutes. Group III received the same treatment as group II, along with pre-operative and repeated post-operative conjunctival applications of 0.4 mg/ml MMC for 10 minutes. Surgical success, IOP < 21 mmHg, lasted for a median of 8 days in group I, 56 days in group II and 75 days in group III. Compared with group I, cellular proliferation was significantly inhibited in group II and mostly inhibited in group III. No significant ocular toxicity or profound hypotony was observed. Histological examination of group III on the 90th day after operation showed patent scleral tunnel and hypocellular loose connective tissue in the conjunctival bleb. These results demonstrated that a series of pre-, intra- and repeated postoperative topical applications of mitomycin-C had a prolonged effect in inhibiting wound healing after trabeculectomy in monkeys.

The diagnostic value of IgM to natural trisaccharide phenylpropionyl bovine serum albumin in leprosy patients: a preliminary report from Taiwan

An evaluation was made of the serum anti-phenolic-glycolipid-I (PGL-I) IgM levels of leprosy patients in the Taiwan area by enzyme-linked immunosorbent assay (ELISA) with a specific synthetic PGL-I antigen and natural trisaccharide phenylpropionyl bovine serum albumin (NT-P-BSA). Fifty-five blood samples were collected from 24 tuberculoid and 31 lepromatous leprosy patients and 21 healthy age- and sex-matched subjects. Among these groups, lepromatous patients had the highest levels of IgM and anti-NT-P-BSA IgM with a good correlation between these two levels (p less than 0.01). Tuberculoid patients also had higher levels than normal subjects. Wide variation in the standard deviation and decreased levels within the cutoff value of some lepromatous patients may be due to various periods of anti-leprosy treatment. Serial anti-NT-P-BSA IgM assessments in response to anti-leprosy treatment may provide more information and serve as a guideline for therapy.

Cryofibrinogenemia: report of a case

Cryofibrinogenemia, a rare disease, is diagnosed by the presence of reversible cryoprecipitate in plasma, which may cause various clinical manifestations of thromboembolic or hemorrhagic disorders. A 66-year-old female patient suffered from recurrent reticulate erythema, purpura and gangrene on the distal portion of the extremities and face during the winter for 5 years. Cryofibrinogenemia was proven with the following evidences: (1) Histopathologic findings revealed many eosinophilic cylinders, about 6-9 microns in diameter, deposited within the lumen of the blood vessels in the dermis and subcutaneous tissue. There was no evidence of vasculitis. These cylinders were fibrinogen in nature, as proven by direct immunofluorescence. (2) Cryofibrinogen was detected in the citrated plasma, which was confirmed by double immunodiffusion, the presence of an IgG-kappa M protein was also revealed by immunofixation. Debridement and skin grafts were performed, and prednisolone combined with cyclophosphamide were given. Skin lesions improved without recurrence, and the "cryocrit" decreased from 13.6% to less than 2% during the follow up. We conclude that if there is any case with the similar cutaneous manifestations, cryofibrinogenemia should be considered.

Trabeculectomy with simultaneous topical application of mitomycin-C in refractory glaucoma

From May 1981 to Feb. 1989 trabeculectomy with per-operative topical application of mitomycin C was performed on eyes with refractory glaucoma. All eyes had undergone prior one, two or more than two antiglaucoma surgeries without success for IOP control. Other risk factors in the present series of eyes included young age, aphakia, rubeosis and glaucoma secondary to trauma or associated with anterior uveitis. 59 eyes underwent trabeculectomy with mitomycin application. 14 eyes were lost. 45 eyes of 42 cases, 33 eyes of 31 males and 12 eyes of 11 females were followed for a period of 1 to 8 years, an average 3.0 +/- 1.9 years. The success for IOP control less than 21 mmHg was 77.8%, 35/45 eyes. The success rates were 92%, 11/12 eyes in females and 73%, 24/33 eyes in males. Complications reported in 5-fluorouracil studies such as corneal epithelial toxicity and delayed healing of conjunctival wound were not encountered. The histo-pathological changes of wound healing after trabeculectomy with topical mitomycin application was discussed. In the healing process success to achieve filtration is more likely by pharmacolocally interferring with earlier steps in the process. We recommend the use of per-operative topical application of mitomycin C during trabeculectomy in eyes with uncontrolled glaucoma and poor prognosis, specifically after previous cataract extraction or unsuccessful antiglaucoma surgery.