Antitumor activity of triazine mimic antibiotics for DNA-binding implications (impressive activity in vitro against a variety of tumor types in the NCI-60 screen): NSC 710607 to fight HCT-116 human colon carcinoma cell lines in vivo using the hollow fiber assay and xenograft mouse models

PURPOSE

Successful clinical applications of DNA-directed selective cytotoxic agents disrupt the vital replication/transcription processes and ultimately lead to cancer cell death. This study aimed to examine the growth screen of two lead triazine compounds in a number of cell lines and xenografts and to develop anticancer agents with noncovalent binding affinity bringing fewer side effects.

METHODS

The NCI initial hollow fiber test was performed using an established procedure. The cytostatic and cytocidal capacities of the test compounds were assessed by evaluating cytotoxicity by simply performing a standard cellular viability assay. The nude mouse human tumor xenograft system was used as an in vivo model.

RESULTS

More sensitive drug with sub-micromolar activity met the interdisciplinary criteria for testing and was referred to evaluations in subcutaneous colorectal carcinoma HCT-116 human tumor xenografted into nude mice. Principal findings of the study: total cytostasis, almost nontoxic schedules, specific working hypotheses, strong rationale for the potential use, and important general implications (relevance to human biology). NSC 710607 displayed in vivo better than Cisplatin and 5-fluorouracil abilities to significantly decrease tumor growth.

CONCLUSION

Cell proliferation can be reduced or stopped in vivo in view of the xenograft results. The mimic molecule behaves as DNA-binding antitumor antibiotics with great potential as general anticancer agents and deserves further trials. NSC 710607 represents the result of a design strategy with outstanding potential. This study also identifies the prognostic significance and is likely to translate to other species or systems.

Potent dual EGFR/Her4 tyrosine kinase inhibitors containing novel (1,2-dithiolan-4-yl)acetamides

Modifications at C₆ and C₇ positions of 3-cyanoquinolines 6 and 7 led to potent inhibitors of the ErbB family of kinases particularly against EGFR^WT and Her4 enzymes in the radioisotope filter binding assay. The lead (4, SAB402) displayed potent dual biochemical activities with EGFR^WT/Her4 IC₅₀ ratio of 80 due to its potent inhibition of Her4 activity (IC₅₀ 0.03 nM), however, the selectivity towards activating mutations (EGFR^L858R, EGFR^ex19del) was decreased. Inhibitor 4 also exhibited excellent growth inhibition in seven different cancer types and reduced cell viability in female NMRI nude mice in the intraperitoneally implanted hollow fibers which have been loaded with MOLT-4 (leukemia) and NCI-H460 (NSCLC) cells in a statistically significant manner.

Bioactivity-Guided Isolation of Totarane-Derived Diterpenes from Podocarpus neriifolius and Structure Revision of 3-Deoxy-2α-hydroxynagilactone E

Bioactivity-guided phytochemical investigation of Podocarpus neriifolius D. Don. (Podocarpaceae) has led to the isolation of one new (2) and three known (1, 3, and 4) B-type podolactones, along with three totarane-type diterpenes (5-7). Their structures were determined by interpretation of High Resolution ElectroSpray Ionization Mass Spectrometry (HRESIMS) and 1D and 2D NMR data, and comparison with the values reported in the literature. The structure of compound 1, previously identified as 3-deoxy-2α-hydroxynagilactone E (8), was revised as its 2β-epimer, which has been reported recently as a new compound. All of the isolates were evaluated for their antiproliferative activity against a panel of four human cancer cell lines, namely, ovarian (OVCAR3), breast (MDA-MB-231), colon (HT-29), and melanoma (MDA-MB-435), and compounds 1 and 3 were found to be cytotoxic with IC₅₀ values in the low micromolar range for most of the cell lines used. The major compound, inumakilactone A (3), was further tested in vivo using the HT-29, MDA-MB-435, and OVCAR3 cells in a murine hollow fiber model, for the first time.

Preclinical anticancer effectiveness of a fraction from Casearia sylvestris and its component Casearin X: in vivo and ex vivo methods and microscopy examinations

ETHNOPHARMACOLOGICAL RELEVANCE

Casearia sylvestris (Salicaceae) is found in South America and presents antiulcerogenic, cytotoxic, antimicrobial, anti-inflammatory and antihypertensive activities.

AIM OF THE STUDY

To assess the in vivo and ex vivo antitumor action of a fraction with casearins (FC) and its main component - Casearin X-isolated from C. sylvestris leaves.

MATERIALS AND METHODS

Firstly, Sarcoma 180 bearing Swiss mice were treated with FC and Cas X for 7 days. Secondly, BALB/c nude animals received hollow fibers with colon carcinoma (HCT-116) or glioblastoma (SF-295) cells and were treated with FC for 4 days. On 5th day, proliferation was determined by MTT assay.

RESULTS

FC 10 and 25mg/kg/day i.p. and 50mg/kg/day oral and Cas X 25mg/kg/day i.p. and 50mg/kg/day oral revealed tumor growth inhibition rates of 35.8, 86.2, 53.7, 90.0 and 65.5% and such tumors demonstrated rare mitoses and coagulation necrosis areas. Similarly, FC reduced multiplying of HCT-116 and SF-295 cells when evaluated by the Hollow Fiber Assay (2.5 and 5mg/kg/day i.p. and 25 and 50mg/kg/day oral), with cell growth inhibition rates ranging from 33.3 to 67.4% (p<0.05). Flow cytometry experiments revealed that FC reduced membrane integrity and induced DNA fragmentation and mitochondrial depolarization (p<0.05).

CONCLUSIONS

FC and Cas X were efficient antitumor substances against murine and human cancer cells and caused reversible morphological changes in liver, kidneys and spleens, emphasizing clerodane diterpenes as an emerging class of anticancer molecules.

Preclinical efficacy testing for stomach and liver cancers

PURPOSE

Hollow fiber assays offer an early in vivo method of anticancer drug screening. The assays have been optimized for human cancers originating from the lung, breast, colon, ovary, and brain, but not from the stomach and liver. The current study focused on optimization of hollow fiber assays for gastric and hepatocellular carcinoma cell lines.

MATERIALS AND METHODS

Gastric (SNU-16, SNU-484, SNU-668) and hepatocellular (HepG2, SK-Hep-1, Hep3B) carcinoma cell lines in hollow fibers were transplanted subcutaneously and intraperitoneally into mice, which were subsequently treated with a standard anticancer agent, paclitaxel. The hollow fiber activity of paclitaxel in each cell line was compared with the xenograft activity.

RESULTS

Using optimized inoculation densities and schedules, treatment with paclitaxel was effective in gastric carcinoma cell lines, SNU-16 and SNU-484, but not in SNU-668. In the hollow fiber assays, paclitaxel was effective in hepatocellular carcinoma cell lines, HepG2 and SK-Hep-1, but not in Hep3B. Consistent with the results of the hollow fiber assay, SNU-16 and SNU-484, but not SNU-668, showed tumor regression, and HepG2 and SK-Hep-1, but not Hep3B, showed effective tumor responses following treatment with paclitaxel in xenograft models. When EW7197, a novel compound, and flavopiridol were tested in SNU-16 cells under optimized conditions, the hollow fiber activity showed good correlation with the xenograft activity of each compound.

CONCLUSION

Our protocols may be useful for screening candidate small molecules that may exhibit activity against stomach and liver cancers, both of which are common in Korea.

Correlative effect between in vivo hollow fiber assay and xenografts assay in drug screening

PURPOSE

This study was carried out to assess the usage of an in vivo hollow fiber assay to screen drugs with highly predictive accuracy.

MATERIALS AND METHODS

The assay systems used were the hollow fiber and xenografts assays. The hollow fiber assay was carried out with the following steps; preparation of fibers, preparation of cells, loading and implanting fibers, treatment with drugs, removal of fibers and assaying for the cell viability by the MTT assay. For the xenografts assay, cell suspensions were subcutaneously transplanted into the mice. Therapy was started when the tumor volume reached 100 approximately 200 mm(3). The tumor volumes were calculated using the formula V=[length+(width)(2)]/2, and used for evaluating the efficacy of the drugs. The drug treatment doses used were adriamycin 2.1 mg/kg, mitomycin-C 0.25 mg/kg, 5-fluorouracil 24.5 mg/kg and paclitaxel 2.5 mg/kg, and administrated intravenously five times daily.

RESULTS

The correlation between the xenografts and hollow fiber assays was evaluated in 20 tumor cell lines and 4 anti-cancer agents. In the 20 tumor cell lines, the overall predictive accuracy of the hollow fiber assay for sensitivity was 83%, with a predictive accuracy for resistance of 92%.

CONCLUSION

The hollow fiber assay was assessed as effective in drug efficacy evaluation, and found to be compatible with that of the xenografts assay.