Suppression of NAD(P)H-quinone oxidoreductase 1 enhanced the susceptibility of cholangiocarcinoma cells to chemotherapeutic agents

BACKGROUND

Cholangiocarcinoma (CCA) is highly resistant to most of the known chemotherapeutic treatments. NAD(P)H-quinone oxidoreductase 1 (NQO1) is an antioxidant/detoxifying enzyme recently recognized as an important contributor to chemoresistance in some human cancers. However, the contribution of NQO1 to chemotherapy resistance in CCA is unknown.

METHODS

Two CCA cell lines, KKU-100 and KKU-M214, with high and low NQO1 expression levels, respectively, were used to evaluate the sensitivity to chemotherapeutic agents; 5-fluorouracil (5-FU), doxorubicin (Doxo), and gemcitabine (Gem). NQO1 and/or p53 expression in KKU-100 cells were knocked down by siRNA. NQO1 was over-expressed in KKU-M214 cells by transfection with pCMV6-XL5-NQO1 expression vector. CCA cells with modulated NQO1 and/or p53 expression were treated with chemotherapeutic agents, and the cytotoxicity was assessed by SRB assay. The mechanism of enhanced chemosensitivity was evaluated by Western blot analysis.

RESULTS

When NQO1 was knocked down, KKU-100 cells became more susceptible to all chemotherapeutic agents. Conversely, with over-expression of NQO1 made KKU-M214 cells more resistant to chemotherapeutic agents. Western blot analysis suggested that enhanced chemosensitivity was probably due to the activation of p53-mediated cell death. Enhanced susceptibility to chemotherapeutic agents by NQO1 silencing was abolished by knockdown of p53.

CONCLUSIONS

These results suggest that inhibition of NQO1 could enhance the susceptibility of CCA to an array of chemotherapeutic agents.

Phase II study of irinotecan with bolus and high dose infusional 5-FU and folinic acid (modified de Gramont) for first or second line treatment of advanced or metastatic colorectal cancer

We investigated the activity of irinotecan given with a more convenient modified bimonthly de Gramont regimen of bolus and infusional 5-fluorouracil [IrMdG] in advanced or metastatic colorectal cancer in the first and second line setting. Irinotecan 180 mg m(-2) was infused over 90 min. L-folinic acid 175 mg or d,l folinic acid 350 mg was given over 2 h followed by a bolus of 5-fluorouracil (400 mg m(-2)) and a 46 h continuous infusion of 5-fluorouracil (2.4-2.8 g m(-2)). Forty-six previously untreated patients (Group A) and 36 who had received 5-fluorouracil for metastatic disease (Group B) were recruited. Seventy-eight patients were evaluable for response. A partial response was seen in 13 out of 43 (30% [95%CI 28.1-31.9%]) in Group A and 8/35 (23% [95% CI 17.9-28.1%]) in Group B. 40% (95%CI 38.1-41.9%) of Group A and 26% (95% CI 20.9-31.1%) of Group B patients achieved disease stabilisation. The median progression free survival from the start of this treatment was 7 months (95% CI 4.4-9.6 months) in Group A and 5 months (95% CI 2.8-7.2 months) in Group B. Median overall survival was 14 months (95% CI 9.0-18.9) in Group A and 11 months (95% CI 5.9-16.1) in Group B. Grade 3-4 toxicity in both treatment groups were similar; leucopenia 17% and diarrhoea 7-8%. Grade 3-4 mucositis was not seen and severe alopecia affected only three patients. IrMdG is an active and well-tolerated regimen for both the first and second line treatment of advanced colorectal cancer.

Effect of heating temperature and time on pharmaceutical characteristics of albumin microspheres containing 5-fluorouracil

In this study, we found that both heating temperature and heating time affect mean particle size, particle size distribution, and drug entrapment efficiency of albumin microspheres. The change in heating temperature may affect the particle size of the product, especially when heating is carried out at a lower temperature (90°C–120°C). Hence the temperature should be selected on the basis of desired size range. Given that it is desirable for a maximum amount of the drug used in the preparation to become entrapped in microspheres, heating temperature and heating time for denaturation of albumin should be selected cautiously, as both have a significant effect on drug entrapment efficiency. In the present case, the highest entrapment was found in batches prepared by heating at 90°C for 5 minutes. However, the extent of stabilization at the selected temperature and the time of heating should also be taken into consideration, as they may affect the release of drugs to target tissue.

The Inhibitory Effects of HYDAMTIQ, a Novel PARP Inhibitor, on Growth in Human Tumor Cell Lines With Defective DNA Damage Response Pathways

The poly(ADP-ribose) polymerase (PARP) enzymes play a key role in the regulation of cellular processes (e.g., DNA damage repair, genomic stability). It has been shown that PARP inhibitors (PARPIs) are selectively cytotoxic against cells having dysfunctions in genes involved in DNA repair mechanisms (synthetic lethality). Drug-induced PARP inhibition potentiates the activity of anticancer drugs such as 5-fluorouracil in enhancing DNA damage, whose repair involves PARP-1 activity. The aim of this study was to evaluate the inhibitory effects of a novel PARPI, HYDAMTIQ, on growth in human tumor cell lines characterized by different features with regard to DNA damage response pathways (BRCA mutational status, microsatellite status, and ATM expression level) and degree of sensitivity/resistance to 5-fluorouracil. HYDAMTIQ showed a more potent inhibitory effect on cell growth in a BRCA2 mutant cell line (CAPAN-1) compared with wild-type cells (C2-6, C2-12, and C2-14 CAPAN-1 clones, and MCF-7). No statistically significant difference was observed after HYDAMTIQ exposure between cells having a different MS status or a different MRE11 mutational status. HYDAMTIQ induced greater antiproliferative effects in SW620 cells expressing a low level of ATM than in H630 cells expressing a high level of ATM. Finally, the combination of HYDAMTIQ and 5-fluorouracil exerted a synergistic effect on the inhibition of SW620 cell growth and an antagonistic effect on that of H630 cell growth. Our results show that the novel PARP inhibitor HYDAMTIQ potently inhibits the growth of human tumor cells with defective DNA damage response pathways and exerts synergistic cytotoxicity in combination with 5-fluorouracil. These data provide relevant examples of synthetic lethality and evidence for further development of this novel PARPI.

Cost-Effectiveness Analysis of Adjuvant Stage III Colon Cancer Treatment at Veterans Affairs Medical Centers

The objective of this study was to evaluate the real-world cost effectiveness of adjuvant stage III colon cancer chemotherapy regimens, given that previous analyses have been based on data from clinical trials. The study was designed using integrated decision tree and Markov model, which was developed to evaluate the cost effectiveness of 5-fluorouracil/leucovorin (5-FU/LV), capecitabine, and the combination of each with oxaliplatin. The analysis was performed from a US Veterans Affairs perspective via retrospectively collected data, over a 5-year model time horizon. Outcome and cost data were used to calculate cost per quality adjusted life year (QALY), and one-way and probabilistic sensitivity analyses were performed. In the base case analysis, capecitabine and capecitabine plus oxaliplatin both cost more and were less effective than other regimens, and 5-FU/LV plus oxaliplatin, compared to 5-FU/LV alone, resulted in a cost of $25,997 per QALY gained. Model results were generally robust to parameter variation. Capecitabine plus oxaliplatin could be economically reasonable if full dosing occurred ≥76% of the time (base case 42%). In a real-world setting, the addition of oxaliplatin to 5-FU/LV is more effective but also more costly than 5-FU/LV alone. If full dosing of capecitabine-containing regimens can be assured, they may also be cost-effective strategies.

Bacillus coagulans 198 and L-glutamine in combination attenuated intestinal mucositis in a 5-FU-induced BALB/c mouse model via modulation of gut microbial community structure and diversity

5-Fluorouracil (5-FU) disrupts intestinal cells and causes dysbiosis in the gut microbiota. This study explores the potential of Bacillus coagulans-198 (BC198) to mitigate gut microbiota imbalance and mucositis caused by 5-fluorouracil. L-glutamine is used to alleviate mucositis, and this study found that BC198 exhibits protective effects on the gut, including maintaining a healthy microbiota and reducing intestinal inflammation, regardless of whether L-glutamine is used in combination. Therefore, it can help reduce the deterioration of the gut environment caused by 5-fluorouracil. BC198 can be provided to cancer patients to prevent severe side effects, thereby improving their treatment outcomes and nutritional status.