A phase II study to explore biomarkers for the use of mFOLFOX6/XELOX plus bevacizumab as a first-line chemotherapy in patients with metastatic colorectal cancer (WJOG7612GTR).

BACKGROUND: The purpose of this prospective study was to assess the ability of plasma vascular endothelial growth factor-A short isoforms (pVEGF-Asi) to predict bevacizumab (BV) efficacy and to explore other circulating biomarkers in metastatic colorectal cancer (mCRC) patients treated with modified FOLFOX6/XELOX plus BV (mFOLFOX6/XELOX + BV). PATIENTS AND METHODS: Pre-treatment plasma samples were collected from 100 mCRC patients receiving first-line chemotherapy with mFOLFOX6/XELOX + BV. The plasma levels of 11 angiogenesis-associated molecules, including pVEGF-Asi and 22 cancer-associated gene mutations in circulating tumor DNA, were analyzed. For the primary endpoint, we assumed that the hazard ratio (HR) for progression-free survival (PFS) calculated using a Cox proportional hazards model was <1.15, comparing patients with a high versus those with a low pVEGF-Asi level divided according to the median pVEGF-Asi value. RESULTS: The median value of pVEGF-Asi was 37 (range 6.5-262) pg/ml. The HR for PFS between the high and low pVEGF-Asi patient groups was 1.3 [95% confidence interval (CI) 0.8-2.1; log rank, P = 0.25], which was larger than the predefined threshold of 1.15. The multivariate analysis demonstrated that PFS was significantly associated with plasma intercellular adhesion molecule-1 (pICAM-1) (≥190.0 versus <190.0 ng/ml; HR 2.1; 95% CI 1.3-3.5), RAS (mutant versus wild; HR 2.5; 95% CI 1.5-4.3), and FBXW7 (mutant versus wild; HR 2.8; 95% CI 1.2-6.8), whereas overall survival was significantly associated with pICAM-1 (HR 2.0; 95% CI 1.1-3.7) and RAS (HR 2.6; 95% CI 1.5-4.6). CONCLUSIONS: The addition of BV was unable to compensate for the poor PFS associated with a high pVEGF-Asi level, suggesting that pVEGF-Asi is unlikely to be a good predictive biomarker of the efficacy of mFOLFOX6/XELOX + BV therapy. The clinical significance of circulating ICAM-1, mutant RAS, and mutant FBXW7 levels should be studied further.

Differential roles of STAT3 depending on the mechanism of STAT3 activation in gastric cancer cells.

BACKGROUND: Signal transducer and activator of transcription 3 (STAT3) is a transcription factor that is activated in response to growth factors and cytokines, and which contributes to the regulation of cell proliferation, apoptosis, and motility in many human tumour types. METHODS: We investigated the mechanisms of STAT3 activation and the function of STAT3 depending on its mechanism of activation in gastric cancer cells. RESULTS: The MET-tyrosine kinase inhibitor (TKI) and cell transfection with a small interfering RNA (siRNA) specific for MET mRNA inhibited STAT3 phosphorylation in MET-activated cells, indicating that STAT3 activation is linked to MET signalling. Forced expression of a constitutively active form of STAT3 also attenuated MET-TKI-induced apoptosis, suggesting that inhibition of STAT3 activity contributes to MET-TKI-induced apoptosis. MKN1 and MKN7 cells, both of which are negative for MET activation, produced interleukin-6 (IL-6) that activated STAT3 through the Janus kinase pathway. Depletion of STAT3 by siRNA inhibited migration and invasion of these cells, suggesting that STAT3 activated by IL-6 contributes to regulation of cell motility. CONCLUSION: Our data thus show that activated STAT3 contributes to either cell survival or motility in gastric cancer cells, and that these actions are related to different mechanisms of STAT3 activation.

Thymidylate synthase as a determinant of pemetrexed sensitivity in non-small cell lung cancer.

BACKGROUND: Although a high level of thymidylate synthase (TS) expression in malignant tumours has been suggested to be related to a reduced sensitivity to the antifolate drug pemetrexed, no direct evidence for such an association has been demonstrated in non-small cell lung cancer (NSCLC). We have now investigated the effect of TS overexpression on pemetrexed sensitivity in NSCLC cells. METHODS: We established NSCLC cell lines that stably overexpress TS and examined the effects of such overexpression on the cytotoxicity of pemetrexed both in vitro and in xenograft models. We further examined the relation between TS expression in tumour specimens from NSCLC patients and the tumour response to pemetrexed by immunohistochemical analysis. RESULTS: The sensitivity of NSCLC cells overexpressing TS to the antiproliferative effect of pemetrexed was markedly reduced compared with that of control cells. The inhibition of DNA synthesis and induction of apoptosis by pemetrexed were also greatly attenuated by forced expression of TS. Furthermore, tumours formed by TS-overexpressing NSCLC cells in nude mice were resistant to the growth-inhibitory effect of pemetrexed observed with control tumours. Finally, the level of TS expression in tumours of non-responding patients was significantly higher than that in those of responders, suggestive of an inverse correlation between TS expression and tumour response to pemetrexed. CONCLUSION: A high level of TS expression confers a reduced sensitivity to pemetrexed. TS expression is thus a potential predictive marker for response to pemetrexed-based chemotherapy in NSCLC patients.

Roles of BIM induction and survivin downregulation in lapatinib-induced apoptosis in breast cancer cells with HER2 amplification.

Lapatinib, a dual tyrosine kinase inhibitor of the epidermal growth factor receptor and human epidermal growth factor receptor 2 (HER2), is clinically active in patients with breast cancer positive for HER2 amplification. The mechanism of this anti-tumor action has remained unclear, however. We have now investigated the effects of lapatinib in HER2 amplification-positive breast cancer cells with or without an activating PIK3CA mutation. Lapatinib induced apoptosis in association with upregulation of the pro-apoptotic protein Bcl-2 interacting mediator of cell death (BIM) through inhibition of the MEK-ERK signaling pathway in breast cancer cells with HER2 amplification. RNA interference (RNAi)-mediated depletion of BIM inhibited lapatinib-induced apoptosis, implicating BIM induction in this process. The pro-apoptotic effect of lapatinib was less pronounced in cells with a PIK3CA mutation than in those without one. Lapatinib failed to inhibit AKT phosphorylation in PIK3CA mutant cells, likely because of hyperactivation of the phosphatidylinositol 3-kinase (PI3K) signaling pathway by the mutation. Depletion of PIK3CA (a catalytic subunit of PI3K) revealed that survivin expression is regulated by the PI3K pathway in these cells, suggesting that insufficient inhibition of PI3K-survivin signaling is responsible for the limited pro-apoptotic effect of lapatinib in HER2 amplification-positive cells with a PIK3CA mutation. Consistent with this notion, depletion of survivin by RNAi or treatment with a PI3K inhibitor markedly increased the level of apoptosis in PIK3CA mutant cells treated with lapatinib. Our results thus suggest that inhibition of both PI3K-survivin and MEK-ERK-BIM pathways is required for effective induction of apoptosis in breast cancer cells with HER2 amplification.

Measurement of the coherence of synchrotron radiation.

The first-order spatial (transverse) coherence of synchrotron radiation has been measured using a Young's interferometer at BL28A (a helical-undulator beamline) of the Photon Factory, KEK. The range of the photon energy is about 70-180 eV. The visibility of the fringe was found to depend largely on the electron emittance and the intrinsic photon emittance. In principle, it is possible to gain knowledge of the very small electron emittance, of the order of 10(-10) m rad, without disturbing the electron beam in the storage ring.

Relationship between spatial coherence of synchrotron radiation and emittance.

Analytical calculation of the first-order spatial coherence for the Gaussian beam and the exact numerical calculation for synchrotron radiation are compared in this paper. The approximation of regarding synchrotron radiation as a Gaussian beam is often used to investigate the brightness, the flux and some qualitative properties. Calculations show that synchrotron radiation does not have as high coherence as the Gaussian beam because of the beam profile, the phases of the wave and the polarization. If one can measure the beam size and the spatial coherence of synchrotron radiation, it is possible to determine the total photon beam emittance without any knowledge of the Twiss parameters of the ring.

Skinfold compressibility in Japanese university students.

It is well known that caliper readings decline after the initial application of the caliper to the skinfold (dynamic compressibility). In addition to this compressibility, there is also a variability of skinfold compressibility at different body sites (static compressibility). To investigate this static variability, a comparison was made between skinfold thickness obtained from using caliper and thickness derived from an ultrasound image (B scan-mode) at sixteen skinfold sites of 96 non-athletic students in good health (45 men and 41 women). The skinfold compressibility is defined as: (uncompressed value-compressed value) x 100/uncompressed value. The patterns created by the plots of skinfold compressibility across the sixteen body sites were similar for both sexes although the inter-site variability is quite large (significant at 0.01 level on ANOVA). Women tend to have greater skinfold compression in the trunk area and less in the limbs as compared with men. This sex difference may be caused by the sex differences of skin thickness and skin tension (subcutaneous space pressure). The marked inter-site variability in skinfold compressibility suggests the need for caution in estimates of fat mass using skinfold calipers.

Treatment of diabetes insipidus with DDAVP.

The treatment of a patient with diabetes insipidus (DI) is described, and the general treatment of the syndrome is reviewed. The patient was a 16-year-old male who had experienced pain, inflammation and tenderness in the left gluteal region owing to an abcess at the site of intramuscular injection of vasopressin tannate in oil (VTO). (He had been diagnosed as having DI at age 8. Since then, he had been maintained on VTO, lypressin and posterior pituitary snuff.) After the abscess healed during hospital treatment, VTO was stopped and the patient's urinary output increased sharply; urine specific gravity and osmolarity decreased correspondingly. Three days after stopping VTO, the investigational drug, 1-deamino-8-D-arginine vasopressin (DDAVP), was begun at 10 microgram every 12 hours. The dose was eventually increased to 20 microgram every 12 hours, and the patient was discharged on this regimen which controlled his urine output, specific gravity and osmolarity. Other treatments reviewed include antidiuretic-hormone-replacement agents (vasopressin, lypressin) and drugs used to potentiate low ADH levels (chlorpropamide, clofibrate and carbamazepine).