No abstract

Anti-epidermal growth factor receptor (EGFR) monoclonal antibodies (Mabs) show high efficacy in about 50% of colorectal cancer (CRC) patients with wild-type KRAS. However, < 20% of patients with KRAS wild-type CRC have continued therapeutic effects with these agents, and acquired resistance to treatment has become a serious clinical problem. In this study, to clarify the factors related to acquisition of resistance to cetuximab (Cmab) and establish countermeasures against such acquired resistance, we conducted a comprehensive protein analysis via a proteomics approach using acquired resistance cell lines derived from Cmab-sensitive CRC cell lines and original cell lines. Cmab-acquired resistance cell lines were generated by continuous exposure of SW48 and C99 cell lines to Cmab. Expression of dCK and zinc finger and BTB domain-containing protein 41 (ZBTB41) increased more than 10-fold, and dual specificity protein phosphatase 3 (DUS3) expression decreased by less than 1/10 with acquisition of resistance to Cmab in both C99 and SW48 cell lines. Because overexpression of dCK is known as a positive indicator of efficacy of nucleoside analogs such as cytarabine or gemcitabine, it is considered that nucleoside analogs activated by dCK may be useful agents in treatment of cancers with acquired Cmab-resistance. In the future, we need to clarify the usefulness of these drugs for the treatment of Cmab resistant CRC and to assess the possibility of restoration of Cmab sensitivity by regulation of ZBTB41 and DUS3 expression.Keyword : cetuximab, colorectal cancer, acquired resistance, protein, dCK, ZBTB41

ObjectivesLenalidomide, a hazardous drug, has strict distribution controls. However, the risk of contamination with lenalidomide when patients take the drug has not been studied and the risk of drug exposure to people in the patient’s living environment is unknown. Thus, we investigated the amount of lenalidomide that could be dispersed during the period between removal of the capsule and returning the used blister packages, and we considered the conditions under which lenalidomide could be dispersed and countermeasures.MethodsThe amount of lenalidomide contamination was measured on the outside of the unused blister packages returned by the patients, on the surface of the capsule, and on the inside of the package immediately after removal of the capsule. In addition, the amount of contamination was measured on the blister packages used by the patients and on the gloves worn by the pharmacists on receipt of the packages. Lenalidomide was analysed by liquid chromatography–tandem mass spectrometry.ResultsLenalidomide amounts on the outside of the unused blister packages returned by the three patients were <10, <10, and 26.8 ng/pack, those on the capsule surface immediately after removal from the packages were 297, 388, and 297 ng/capsule, and those on the inside of packages immediately after removal of all capsules were 143, 184, and 554 ng/pack, respectively. A median of 15.6 ng/pack lenalidomide was detected on the surface of packages used by the patients (n=18). The lenalidomide remaining in the packages immediately after capsule removal (~200 ng/pack), except for the 15.6 ng/pack detected in the packages used by the patients, may have been dispersed in the patient’s living environment (~90% or more). The maximum amount of lenalidomide on the surface of the packages used by the patients was over 2500 ng/pack.ConclusionsThe amount of lenalidomide contamination per package was found to be at least 100 ng less after collection by the pharmacist than immediately after removal of the capsules. Therefore, it is recommended to clean the surrounding area and wash one’s hands after taking the capsules.

In the high-dose methotrexate (HD-MTX) treatment of patients with osteosarcoma, a dose-adjustment method using individual pharmacokinetic parameters (PK method) to optimize the concentration was developed in 2010. However, to the best of our knowledge, the clinical usefulness of the PK method has not been verified until now. In the present retrospective study, to assess the usefulness of the PK method, the achievement rate of an effective and safe concentration range was evaluated. A total of 43 patients with osteosarcoma who were administered HD-MTX therapy (43 first courses and 200 subsequent courses) were enrolled. The MTX dose in the first course was determined using a common method based on body surface area (BSA method); a total of 8-12 g/m 2 was administered as an initial dose for 1 h and a maintenance dose for 5 h. In the subsequent courses, loading and maintenance doses were calculated by the PK method based on the serum MTX concentration profile of the previous course. The effective target concentration during 1-6 h after the start of MTX administration was 700-1,000 µmol/l, whereas the target safe MTX level was less than 10, 1 and 0.1 µmol/l at 24, 48 and 72 h, respectively. Notably, the rate of achieving the effective target concentration was significantly higher when using the PK method as compared to that when using the BSA method. The achievement rate of the safe target concentration at 24, 48 and 72 h when using the PK method was significantly higher. Additionally, the incidence of abnormal laboratory values of aspartate aminotransferase and alanine aminotransferase was significantly lower when using the PK method. Therefore, the PK method was suggested to be very useful in HD-MTX therapy for patients with osteosarcoma.

Cigarette smoking is known to impact the promotion of carcinogenesis and tumor metastasis. On the other hand, some components in smoke were found to have health-promoting effects, and cancer suppressor effects of components in tobacco smoke have attracted attention. Although some studies showed the cancer suppressive effect of cigarette smoke extract (CSE) in vitro study, the effect of CSE administration on cancer is controversial. In this study, we investigated the effect of CSE-administration on tumor metastasis in a spontaneous tumor metastasis model using B16-BL6 cells, which is more clinical conditions. C57BL/6NCr mice were subcutaneously inoculated B16-BL6 cells into the footpad of the right rear leg. CSE was intraperitoneally administrated for 28 days from the day of inoculation. At 2 weeks after inoculation, the primary focus was excised. Subsequently, survival days of the mice were recorded to determine the effect of CSE-administration on spontaneous metastasis. The effect of CSE, α, β-unsaturated ketones, and aldehydes on B16-BL6 cell invasiveness were confirmed by matrigel invasion assay. Survival days of mice injected with 100% CSE was significantly shortened than that of control. B16-BL6 cell invasiveness was accelerated by the treatment with 0.1% CSE and 3 μM of crotonaldehyde. Intraperitoneal CSE-administration may progress spontaneous metastasis of B16-BL6 cells via enhancement of B16-BL6 cell invasiveness. As the cause, we found that crotonaldehyde contained in CSE may enhance the invasion ability of cancer cells. To clarify the cancer-suppressing effect of tobacco components, the effect of crotonaldehyde-removed CSE on tumor should be assessed in detail. Keywords: cigarette smoke extract (CSE), metastasis, crotonaldehyde (CA), B16-BL6 mouse melanoma cells, invasion