Targeting NAD(P)H:Quinone Oxidoreductase (NQO1) in Pancreatic Cancer.

NAD(P)H: Quinone oxidoreductase (NQO1) functions as an important part of cellular antioxidant defense by detoxifying quinones, thus preventing the formation of reactive oxygen species. The aims of our study were to determine if NQO1 is elevated in pancreatic cancer specimens and pancreatic cancer cell lines and if so, would compounds previously demonstrated to redox cycle with NQO1 be effective in killing pancreatic cancer cells. Immunohistochemistry of resected pancreatic specimens demonstrated an increased immunoreactivity for NQO1 in pancreatic cancer and pancreatic intraepithelial neoplasia (PanIN) specimens versus normal human pancreas. Immunocytochemistry and Western immunoblots demonstrated inceased immunoreactivity in pancreatic cancer cells when compared to a near normal immortalized human pancreatic ductal epithelial cell line and a colonic epithelial cell line. Streptonigrin, a compound known to cause redox cycling in the presence of NQO1, decreased clonogenic survival and decreased anchorage-independent growth in soft agar. Streptonigrin had little effect on cell lines with absent or reduced levels of NQO1. The effects of streptonigrin were reversed in pancreatic cancer cells pretreated with dicumarol, a known inhibitor of NQO1. NQO1 may be a therapeutic target in pancreatic cancer where survival is measured in months. © 2006 Wiley-Liss, Inc.

A comparative analysis of core needle biopsy and final excision for breast cancer: histology and marker expression.

BACKGROUND: Core needle biopsy (CNB) is used increasingly not only to diagnose breast cancer, but to determine tumor histology, grade and marker expression, select neoadjuvant therapy, and predict sentinel lymph node status. Thus, we undertook this study to evaluate the accuracy of CNB as a predictor of breast cancer histology and marker expression. METHODS: We identified 209 Breast Cancer Registry cases with a preoperative CNB and reviewed all clinicopathologic data for accuracy. Statistical analysis was performed with statistical software. RESULTS: CNB unequivocally showed cancer in 93%. Exact tumor histology concordance was 86%. Ductal carcinoma in situ on CNB was upgraded to invasive cancer in 23%. Concordance was substantial for estrogen receptor expression (88%, κ = .71), but kappa values were less than .6 for tumor grade, mitotic rate, progesterone receptor (PR), Ki-67, HER-2/neu, and p53 expression. CONCLUSIONS: Reliance on CNB grade and marker expression for critical decision making may be inadvisable. Further study is warranted to optimize breast cancer patient care.

Management algorithm for pneumatosis intestinalis and portal venous gas: treatment and outcome of 88 consecutive cases.

BACKGROUND: Pneumatosis intestinalis (PI) and portal venous gas (PVG) historically mandated laparotomy due to the high mortality rate associated with mesenteric ischemia. Computed tomography (CT) can identify PI/PVG in patients with ischemic emergencies and benign idiopathic conditions. METHODS: A consecutive series of patients with PI or PVG was reviewed from a single institution over 5 years. Eighty-eight cases of PI/PVG were studied: 74 initial patients (year 1-4) were used to generate a treatment algorithm and fourteen additional cases were used to test the algorithm. RESULTS: PI and PVG were associated with three major clinical subgroups: mechanical causes (n=29), acute mesenteric ischemia (n=29), and benign idiopathic (n=26); four were unclassifiable. Patients with acute mesenteric ischemia were associated with abdominal pain (p=0.01), elevated lactate (>or=3.0 mg/dL; p=0.006), small bowel PI (p=0.04), and calculated vascular disease score (p<0.0005). The three subgroups could be distinguished using the generated algorithm with a sensitivity of 89%, specificity of 100%, and positive predictive value of 100%. CONCLUSIONS: With greater sensitivity of modern CT scans, PI and PVG are being detected in patients with a wide range of surgical and non-surgical conditions. This clinical algorithm can identify subgroups to direct surgical intervention for acute ischemic insults and prevent non-therapeutic laparotomies for benign idiopathic PI and PVG.

Targeting NAD(P)H:quinone oxidoreductase (NQO1) in pancreatic cancer.

NAD(P)H:quinone oxidoreductase (NQO1) functions as an important part of cellular antioxidant defense by detoxifying quinones, thus preventing the formation of reactive oxygen species (ROS). The aim of our study was to determine if NQO1 is elevated in pancreatic cancer specimens and pancreatic cancer cell lines and if so, would compounds previously demonstrated to redox cycle with NQO1 be effective in killing pancreatic cancer cells. Immunohistochemistry of resected pancreatic specimens demonstrated an increased immunoreactivity for NQO1 in pancreatic cancer and pancreatic intraepithelial neoplasia (PanIN) specimens versus normal human pancreas. Immunocytochemistry and Western immunoblots demonstrated increased immunoreactivity in pancreatic cancer cells when compared to a near normal immortalized human pancreatic ductal epithelial cell line and a colonic epithelial cell line. Streptonigrin, a compound known to cause redox cycling in the presence of NQO1, decreased clonogenic survival and decreased anchorage-independent growth in soft agar. Streptonigrin had little effect on cell lines with absent or reduced levels of NQO1. The effects of streptonigrin were reversed in pancreatic cancer cells pretreated with dicumarol, a known inhibitor of NQO1. NQO1 may be a therapeutic target in pancreatic cancer where survival is measured in months.

Efficacy of beta-lapachone in pancreatic cancer treatment: exploiting the novel, therapeutic target NQO1.

NAD(P)H:quinone oxidoreductase (NQO1) is elevated in human pancreatic cancers. We hypothesized that beta-lapachone, a novel 1,2-naphthoquinone with potential antitumor activity in cancer cells expressing elevated levels of NQO1, would induce cytotoxicity in pancreatic cancer cells, wherein this two-electron reductase was recently found elevated. beta-lapachone decreased clonogenic cell survival, metabolic cell viability, and anchorage- independent growth in soft agar. The cytotoxic in vitro effects of beta-lapachone were inhibited with coadministration of dicumarol, a specific inhibitor of NQO1. In preestablished human pancreatic tumor xenografts in nude mice, beta-lapachone demonstrated greater tumor growth inhibition when given intratumorally compared to when complexed with cyclodextrin to increase its bioavailability. Due to the poor prognosis of patients with pancreatic cancer and the limited effectiveness of surgery, chemotherapy, and radiation therapy, treatment regimens based on sound, tumor-specific rationales are desperately need for this disease.

Inhibition of cell growth by overexpression of manganese superoxide dismutase (MnSOD) in human pancreatic carcinoma.

Manganese superoxide dismutase (MnSOD) levels have been found to be low in human pancreatic cancer [Pancreas 26, (2003), 23] and human pancreatic cancer cell lines [Cancer Res. 63, (2003), 1297] when compared to normal human pancreas. We hypothesized that stable overexpression of pancreatic cancer cells with MnSOD cDNA would alter the malignant phenotype. MIA PaCa-2 cells were stably transfected with a pcDNA3 plasmid containing sense human MnSOD cDNA or containing no MnSOD insert by using the lipofectAMINE method. G418-resistant colonies were isolated, grown and maintained. Overexpression of MnSOD was confirmed in two selected clones with a 2-4-fold increase in MnSOD immunoreactive protein. Compared with the parental and neo control cells, the MnSOD-overexpressing clones had decreased growth rates, growth in soft agar and plating efficiency in vitro, while in vivo, the MnSOD-overexpressing clones had slower growth in nude mice. These results suggest that MnSOD may be a tumor suppressor gene in human pancreatic cancer.

Treatment of pancreatic cancer cells with dicumarol induces cytotoxicity and oxidative stress.

NAD(P)H: quinone oxidoreductase (NQO(1)) catalyzes the two-electron reduction of quinones to hydroquinones. This reaction is believed to prevent the one-electron reduction of quinones that would result in redox cycling with generation of superoxide (O(2)(.-)). We have recently demonstrated that inhibition of NQO(1) with dicumarol increases intracellular O(2)(.-) production and inhibits the in vitro malignant phenotype of pancreatic cancer cells (J. Cullen et al., Cancer Res., 63: 5513-5520, 2003). We hypothesized that inhibition of NQO(1) would increase cell killing, induce oxidative stress, and inhibit in vivo tumor growth. EXPERIMENTAL DESIGN AND RESULTS: In the human pancreatic cancer cell line MIA PaCa-2, dicumarol decreased cell viability, as measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and decreased clonogenic survival. Dicumarol increased the percentage of apoptotic cells in a time-dependent and dose-dependent manner as measured by 3,3'-diaminobenzidine staining and flow cytometry, which was associated with cytochrome c release and poly(ADP-ribose) polymerase cleavage. Dicumarol also induced oxidative stress as evidenced by increased total glutathione and oxidized glutathione, as well as sensitizing to cell killing mediated by menadione. In established orthotopic pancreatic tumors in nude mice, intratumoral injections of dicumarol slowed tumor growth and extended survival. CONCLUSIONS: Inhibition of NQO(1) with dicumarol induces cell killing and oxidative stress in pancreatic cancer cells and speculate that dicumarol may prove to be useful in pancreatic cancer therapeutics.