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Abstract Background CHK2 kinase is a tumor suppressor that plays important role in DNA damage signaling, cell cycle regulation and DNA damage induced apoptosis. CHK2 kinase expression was known to be ubiquitous in mammalian cells. CHK2-/- cells were remarkably resistant to DNA damage induced apoptosis, mimicking the clinical behavior of non-small cell lung cancer to conventional chemo and radiation therapy. Result We reported that the CHK2 expression is diminished or absent in both non-small cell lung cancer (NSCLC) cell lines and clinical lung cancer tumor specimens. The absent CHK2 expression in NSCLC was due to hypermethylation of the CHK2 gene promoter, preventing from binding of a transcriptional factor, leading to silence of the CHK2 gene transcription. Conclusion Since the CHK2 null mice showed a remarkable radioresistance, which bear significant similarity to clinical behavior of NSCLC, down-regulation of CHK2 kinase expression by CHK2 gene silencing and methylation in non-small cell lung cancer suggest a critical role of CHK2 kinase in DNA damage induced apoptosis and a novel mechanism of the resistance of NSCLC to DNA damage based therapy.

Objective: Aldehyde dehydrogenase (ALDH) expressing cells have been characterized as possessing stem cell-like properties. We evaluated ALDH+ ovarian cancer stem cell-like properties and their role in platinum resistance. Methods: Isogenic ovarian cancer cell lines for platinum sensitivity (A2780) and platinum resistant (A2780/CP70) as well as ascites from ovarian cancer patients were analyzed for ALDH+ by flow cytometry to determine its association to platinum resistance, recurrence and survival. A stable shRNA knockdown model for ALDH1A1 was utilized to determine its effect on cancer stem cell-like properties, cell cycle checkpoints, and DNA repair mediators. Results: ALDH status directly correlated to platinum resistance in primary ovarian cancer samples obtained from ascites. Patients with ALDHHIGH displayed significantly lower progression free survival than the patients with ALDHLOW cells (9 vs. 3 months, respectively p<0.01). ALDH1A1-knockdown significantly attenuated clonogenic potential, PARP-1 protein levels, and reversed inherent platinum resistance. ALDH1A1-knockdown resulted in dramatic decrease of KLF4 and p21 protein levels thereby leading to S and G2 phase accumulation of cells. Increases in S and G2 cells demonstrated increased expression of replication stress associated Fanconi Anemia DNA repair proteins (FANCD2, FANCJ) and replication checkpoint (pS317 Chk1) were affected. ALDH1A1-knockdown induced DNA damage, evidenced by robust induction of γ-H2AX and BAX mediated apoptosis, with significant increases in BRCA1 expression, suggesting ALDH1A1-dependent regulation of cell cycle checkpoints and DNA repair networks in ovarian cancer stem-like cells. Conclusion: This data suggests that ovarian cancer cells expressing ALDH1A1 may maintain platinum resistance by altered regulation of cell cycle checkpoint and DNA repair network signaling. [ABSTRACT FROM AUTHOR]

Background: Triple-negative breast cancer (TNBC) is a highly diverse group that is associated with an aggressive phenotype. Its treatment has been challenging due to its heterogeneity and absence of well-defined molecular targets. Thus, there is an urgent need to identify novel agents with therapeutic application. NF-κB is over-expressed in many breast cancers; thus, inactivation of the NF-κB pathway could serve as a therapeutic target. Here we report for the first time the anti-tumor activity of panepoxydone (PP), a NF-κB inhibitor isolated from an edible mushroom, in several breast cancer cell lines. Methods: We investigated the effects of PP on cell growth, migration-invasion, apoptosis and EMT-related proteins expression in MCF-7 and TNBC cell lines MDA-MB-231, MDA-MB-468 and MDA-MB-453. Results: Significant antitumor activity was seen in all cell lines, with differential responses noted in cell-line specific manner. Treatment with PP resulted in significant cytotoxicity, decreased invasion, migration and increased apoptosis in all cell lines tested. Up-regulation of Bax and cleaved PARP and down-regulation of Bcl-2, survivin, cyclin D1 and caspase 3 were noted in PP-treated breast cancer cells. The antitumor effect of PP appeared related to its ability to inhibit the phosphorylation of inhibitor of NF-κB (IκBα) with cytoplasmic accumulation. PP treatment also down-regulated FOXM1 which resulted in a reversal of EMT. Similar results were obtained after silencing of NF-kB and FOXM1. Conclusion: Altogether, these studies show, for the first time the antitumor activity of PP against breast cancer cells, in particular TNBC cells. Furthermore, it highlights the concept that optimal treatment of TNBC warrants attention to the differential sensitivity of various TNBC subtypes to therapeutic agents. These results suggest that the PP may be a potentially effective chemopreventive or therapeutic agent against breast cancer. However, additional studies are required to more fully elucidate the mechanism of antitumor effect of PP. [ABSTRACT FROM AUTHOR]

Objectives: Although it does not alter the ERCC1 phenotype, the ERCC1 500C>T (rs11615) polymorphism has undergone a myriad of investigations into its role as a marker for nucleotide excision repair (NER) function in different races, diseases and treatment outcomes. The goal of our study was to test the hypothesis that 500C>T is in linkage disequilibrium (LD) with causative alleles, and that these haplotypes are more frequent in Caucasians with melanoma than in healthy Caucasians or African Americans. Design: In this case-control study, we selected race-specific ERCC1 single-nucleotide polymorphism (SNPs), conducted LD analysis with ERCC1 500C>T and compared the frequency of ERCC1 diplotypes in Caucasians with melanoma (n=165), healthy Caucasians (n=150) and healthy African Americans (n=159). The haplotype was further studied using a fusion gene containing multiple SNPs. ERCC1 Setting: Large cancer institute in the USA. Participants: A total of 165 Caucasian melanoma patients, 159 healthy Caucasian controls and 159 African American healthy controls. Men and women were enrolled in the clinical trial; however, since the screening trial included prostate cancer screening in addition to screening for other cancers, only male controls were available. Outcome measures: The outcome measures were melanoma risk in Caucasians, and LD between ERCC1 SNP, N118N and other race-specific allelic variants. Results: When compared to ERCC1 500C>T alone, a race-specific three-SNP variant haplotype in ERCC1 (comprised of rs11615, rs3212950 and rs3212948) was even more frequent in Caucasians with melanoma than in healthy Caucasians (p=0.0034) or African Americans (p<0.0001). A plasmid containing the variant haplotype was not differentially expressed. Conclusions: We demonstrate that ERCC1 500C>T participates in a previously characterised cancer-risk haplotype found more frequently in Caucasians, while LD is weak in African Americans; this haplotype appears to also be related to melanoma. It is therefore likely that ERCC1 500C>T is only a valid NER, disease or treatment outcome marker in Caucasians. [ABSTRACT FROM AUTHOR]

Considering the paucity of data relating erythropoiesis-stimulating agent (ESA) use to ovarian cancer survival, our objective was to evaluate the effect of ESA as used for the treatment of chemotherapy-induced anemia (CIA) on survival in ovarian cancer patients.A multi-institution retrospective chart review was performed on ovarian cancer patients. Data collection included patient demographic, surgicopathologic, chemotherapy, ESA, and survival data. Patients were stratified by ever-use of ESA and were compared using appropriate statistical methods.A total of 581 patients were eligible for analysis with 39% (n = 229) patients with ever-use of ESA (ESA-YES) and 61% (n = 352) never-use ESA (ESA-NO). Mean age was 60.4 years with most patients having stage IIIC (60%) of papillary serous histological diagnosis (64%) with an optimal cytoreduction (67%). Median follow-up for the cohort was 27 months. Both ESA-YES and ESA-NO groups were similar regarding age, body mass index, race, stage, histological diagnosis, and debulking status. Compared with the ESA-NO group, ESA-YES patients were significantly more likely to experience recurrence (56% vs 80%, P < 0.001) and death (46% vs 59%, P = 0.002). Kaplan-Meier curves demonstrated a significant reduction in progression-free survival for ESA-YES patients (16 vs 24 months, P < 0.001); however, overall survival was statistically similar between the 2 groups (38 vs 46 months, P = 0.10). When stratifying by ever experiencing a CIA, ESA-YES patients demonstrated a significantly worse progression-free survival (17 vs 24 months, P = 0.02) and overall survival (37 vs 146 months, P < 0.001).Our data evaluating the use of ESA as a treatment of CIA in ovarian cancer patients are similar to reports in other tumor sites. Considering that patients who used ESA were more likely to experience recurrence and death and to have decreased survival, the use of ESA in ovarian cancer patients should be limited. [ABSTRACT FROM AUTHOR]

Double prophylaxis for deep venous thrombosis (DVT) with thromboprophylaxis plus sequential compression devices (SCDs) is recommended for high-risk surgical patients with gynecologic oncology. Despite the use of preoperative thromboprophylaxis in clinical trials, the schedule of perioperative low molecular-weight heparin varies widely. We sought to determine the effectiveness and adverse effects of a preoperative dose of anticoagulation in patients with gynecologic oncology.A multi-institutional chart review from January 2006 to July 2008 was performed. Patients with gynecologic oncology who received double prophylaxis for laparotomy were eligible. The patients were grouped according to whether they received preoperative anticoagulation (YES PREOP vs NO PREOP). All patients received postoperative low molecular-weight heparin for thromboprophylaxis and SCDs until discharge. Demographic, surgicopathologic, and complication data were collected.A total of 239 patients were identified: YES PREOP (n = 101) and NO PREOP (n = 138). Groups were similar with respect to demographics, diagnosis, and length of hospital stay. There were 2 DVTs in the YES PREOP group compared with 11 in the NO PREOP group (P = 0.04; relative risk, 0.77). There were also fewer DVT-attributable deaths in the YES PREOP group (0 vs 2; P < 0.001). Postoperative hematocrit (30.2% vs 31.4%; P = 0.42) and number of transfusions (26 vs 14; P = 0.31) were similar.The use of preoperative anticoagulation seems to significantly decrease the risk of DVT in this patient population, and complication rates are not increased. Patients receiving double prophylaxis should receive a preoperative dose of anticoagulation for maximum benefit. [ABSTRACT FROM AUTHOR]

Apigenin is a nontoxic dietary flavonoid that has been shown to possess anti-tumor properties and therefore poses special interest for the development of a novel chemopreventive and/or chemotherapeutic agent for cancer. Ovarian cancer is one of the most common causes of cancer death among women. Here we demonstrate that apigenin inhibits expression of vascular endothelial growth factor (VEGF) in human ovarian cancer cells. VEGF plays an important role in tumor angiogenesis and growth. We round that apigenin inhibited VEGF expression at the transcriptional level through expression of hypoxia-inducible factor 1α (HIF-1α). Apigenin inhibited expression of HIF-1α and VEGF via the PI3K/AKT/p70S6K1 and HDM2/ p53 pathways. Apigenin inhibited tube formation in vitro by endothelial cells. These findings reveal a novel role of apigenin in inhibiting HIF-1 and VEGF expression that is important for tumor angiogenesis and growth, identifying new signaling molecules that mediate this regulation. [ABSTRACT FROM AUTHOR]

Background: CHK2 kinase is a tumor suppressor that plays important role in DNA damage signaling, cell cycle regulation and DNA damage induced apoptosis. CHK2 kinase expression was known to be ubiquitous in mammalian cells. CHK2-/- cells were remarkably resistant to DNA damage induced apoptosis, mimicking the clinical behavior of non-small cell lung cancer to conventional chemo and radiation therapy. Result: We reported that the CHK2 expression is diminished or absent in both non-small cell lung cancer (NSCLC) cell lines and clinical lung cancer tumor specimens. The absent CHK2 expression in NSCLC was due to hypermethylation of the CHK2 gene promoter, preventing from binding of a transcriptional factor, leading to silence of the CHK2 gene transcription. Conclusion: Since the CHK2 null mice showed a remarkable radioresistance, which bear significant similarity to clinical behavior of NSCLC, down-regulation of CHK2 kinase expression by CHK2 gene silencing and methylation in non-small cell lung cancer suggest a critical role of CHK2 kinase in DNA damage induced apoptosis and a novel mechanism of the resistance of NSCLC to DNA damage based therapy. [ABSTRACT FROM AUTHOR]