Combination effects of gefitinib plus cisplatin in non-small cell lung cancer (NSCLC): Why have phase III trials failed?

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Background: Four phase III large scale randomized controlled trials combining standard chemotherapeutics and epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) in advanced NSCLC have failed to show benefit. The mechanism for the failure is still yet not clear. Methods: Seventeen NSCLC cell lines were tested; two had induced P-glycoprotein (Pgp) over-expression. Three of the 4 EGFR mutants exhibited activating mutations. All lines were simultaneously treated with gefitinib plus cisplatin (GC). Selected 4 lines were tested with paclitaxel plus cisplatin (PC) or gefitinib (PG) and three-drug combination (PCG). The MTT assay with application of classical isobole method and statistical analysis was used and dose-log response curves (DRCs) were examined for evaluating the possible resistance mechanisms. Results: We found that combined GC regimen had significant antagonism at the IC50 level (13/15 lines; mean CI=1.184±0.037, P=0.001). The mean CI values of PCG were higher than or comparable with those of PC or PG in either EGFR wild type or mutant cells. DRC analysis mainly showed non-saturable passive resistance, suggesting that gefitinib 0.001–0.3 μM could interfere with cisplatin cell entry in a dose dependent fashion when cisplatin concentrations over 1–3μM, thus leaded to antagonism. Giving gefitinib 24 hours after administration of cisplatin could abolish the antagonism. Conclusions: In NSCLC cells, combination of GC showed antagonistic interaction likely because gefitinib interfered with cisplatin cell entry. Three-drug combination PCG was not better than two-drug combination PC or PG in either EGFR wild type or mutant cells. Clinically, simultaneously combined EGFR TKI with platinum in NSCLC should be avoided regardless of EGFR mutation status.

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A strategy for clinical guidance using PD biomarkers revealed from human primary (HuPrime) tumors transplanted in nude mice

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Background: Most anticancer drug candidates, currently in clinical trials, have clear targets in molecular and cellular systems. However, such molecular targets are not always affected (or not correlated with efficacious endpoints) when the candidate is evaluated in a clinical setting. There is an urgent need to develop better biological tools and models to ease the transition between in vitro and in vivo, and between preclinical and clinical settings. Activation of tyrosine kinases in tumor cells has been recognized as key driving force in malignancy; therefore inhibitors of tyrosine kinases (TKI) have often shown efficacy in preclinical in vivo models and beneficial responses in clinical trials. An increasing number of TKI has been approved as anticancer drugs in selected cancer types. Methods: We have developed a unique platform combining our novel HuPrime™ xenograft models with our PD biomarker technologies. This platform is used to better understand the efficacy of novel drug candidates and generate information critical to maximize the chance of a successful clinical development. To illustrate the usefulness of our platform, we have applied it to understand the pharmacodynamic changes (at the molecular level) which are associated with the activity of sunitinib and sorafenib in our sensitive esophageal HuPrime models. Tumor tissues from sensitive esophageal HuPrime models treated with single dose of the respective drugs (and a vehicle control) have been collected at time-points 4, 8, 16, and 24 hour. Results: We have successfully applied immunohistochemistry (IHC) assays on many molecules covering most pathways including proliferation, apoptotic, necrotic, and cell cycle regulation, G2M phase arrest, DNA damage response, etc. Additional markers including angiogenesis can also be included for certain therapeutic compounds. These tissues have been analyzed with our platform and we have uncovered key molecular events which correlate with the efficacy and potency of the drugs. Conclusions: The PD biomarkers validated in this approach have potential for clinical application and patient stratification.

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The clinical pathogensis significance associated with mutation of APC MCR in colorectal neoplasms

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Background: To explore the clinical pathogensis evalution of codon 1493,1367 and 1328 mutations in MCR (mutation cluster region) of exon 15 of APC (Adenomatous polyposis coli) gene in cases of colorectal neoplasm and the family history. Methods: The specimens from 21 colorectal adenoma specimens groups,16 colorectal carcinoma groups, 20 healthy germline groups with positive familial history and 8 healthy germline groups without familial history. MCR of APC gene were extracted and specificly amplified, then sequenced by sequencer, the codon mutations were analyzed between the 4 groups and various genotypes tested with Chi-square. Results: The codon mutations were three variations: 1493(ACG > ACA), 63/69(91.3%); 1367(CAG > TAG), 1/69(1.4%) and 1328(CAG>TAG), 5/69(7.2%). The allele mutations were checked out four genotypes such as 4478(G→A), 41/69(59.4%); 4478(G/A), 22/69(31.9%); 4096(C/T), 1/69 (1.4%) and 3979(C/T), 5/69(7.2%); but the significant groups status (P<0.05) were shown between the adenoma and nonfamily history group on the analysis of 4478(G→A) and (G/A), also the significant differences were tested between the with and without family history on the analysis of 4478(G→A). The significant differences (P<0.05) in pathogensis mutant phenotypes were involved between 4478(G→A) with 4478(G/A), 4096(C/T) and 3979(C/T), respectively; also showed between 4478(G/A) with 4096(C/T) and 3979(C/T); but not between 4096(C/T) and 3979(C/T) (P>0.05). Conclusions: In our data, the highest mutant frequency 4478(G→A) of 1493(ACG>ACA) presented to the significant phenotype of positive history and adenoma, but 4478 (G/A) were associated with colorectal adenocancer, which was discovered in the different effect to candidators despite the same synonymous mutation. In researches, APC MCR codon 1367 and 1328 genotyping were significantly presented in the colorectal cancergenetic phenotypes in somatic cells only.

No significant financial relationships to disclose.

Correlation between K-ras mutations status and benefit from cetuximab treatment in advanced colorectal cancer

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Background: Cetuximab is a monoclonal antibody that specifically blocks the EGFR. We follow -up study the efficacy and toxicity of cetuximab with chemotherapy in the treatment of advanced colorectal cancer from Chinese in East China. Methods: We analyzed tumor samples from 120 patients with advanced colorectal cancer by direct sequencing, to observe the mutations status in exon 2,3 of K-ras gene. And 30 patients were followed up according the RECIST standard for their treatment outcome of cetuximab plus chemotherapy at 2 -12 months. Results: K-ras mutations were identified in 48 of 120(40%) patients with colorectal cancer in exon2, which including 8 mutation types; 38/48(79.2%) mutations in 12 codon(G12D 43.7%,G12V 25%,G12C 10.4%,G12R 6%,G12S 4%,G12A 2%) and 10/48(18.7%) in 13 codon(G13D 18.7%,G13C 2%). None mutation was found in 61codon of exon3. we observed the clinical efficacy of 30 patients treated by cetuximab plus chemotherapy, of 21 patients with wild-type K-ras tumors as compared with 9 patients with mutated K-ras significantly improved the response rate (5/21 21.8% vs 1/9 11.1%,P<0.01)and the disease control rate (19/21 90.4% vs,2/9 22.2%,P<0.01). There were a few patients with mutated K-ras tumors benefit from cetuximab, in which the fluorescence intensity of mutation cells of all detected tumor tissue approach to 1:3 status by sequencing analysis. The major toxicities of treatment were acne-like rash, which were found in 14/21(66.6%)of patients with wild-type K- ras, and 5/9(55.5%)of patients with mutated K-ras . Conclusions: The East-China patients share the same (40%) mutation frequency and type of k-ras gene with other races . Patients with wild type K-ras mutation have significantly higher Response rate and disease control rate on cetuximab plus chemotherapy treatment .Our results once again show that somatic mutations status of k-ras is a major determinant of cetuximab response in advanced colorectal cancer. There was no statistical correlation between acne-like rash of the major toxicities and mutations status of k-ras. There were a few patients bearing mutated k-ras did benefit from cetuximab, that would need to be validation between Chinese or Ethnicity association phenotype by a large numbers of samples.

No significant financial relationships to disclose.

Preoperative assessment and staging of hilar cholangiocarcinoma with 16-multidetector computed tomography cholangiography and angiography

BACKGROUND/AIMS

To evaluate prospectively the preoperative use of 16-multidetector computed tomography (MDCT) with cholangiography and angiography in determining the resectability of hilar cholangiocarcinoma.

METHODOLOGY

From January 2002 to January 2008, 75 consecutive patients with hilar cholangiocarcinoma underwent preoperative MDCT with cholangiography and angiography. 3D images of the portal vein, hepatic artery, and bile ducts were created and viewed simultaneously. The accuracy of MDCT with cholangiography and angiography was determined by comparison with intraoperative and pathologic findings.

RESULTS

All patients tolerated the CT imaging well and without serious complication. The sensitivity, specificity, and accuracy rates were 92.9%, 100%, and 96% for portal vein invasion and 83.3%, 100%, and 93.3% for hepatic arterial invasion. The accuracy rate of longitudinal tumor extension, using the modified Bismuth-Corlette classification, was 96%. The sensitivity, specificity, and accuracy of prediction of resectability were 95.7%, 82.1%, and 90.7%, respectively.

CONCLUSIONS

Preoperative MDCT with cholangiography and angiography gave a good assessment of the degree of biliary and vascular involvement of hilar cholangiocarcinoma. It also accurately predicted resectability.

Prolongation of rat intestinal allograft survival by administration of triptolide-modified donor bone marrow-derived dendritic cells

Severe graft rejection remains an important obstacle in intestinal transplantation. In this study, dendritic cells (DCs) isolated from rat bone marrow were cultured for 5 days, and triptolide applied for 3 more days. The recipient rats were pretreated with donor triptolide-modified or not modified DC. Small bowel transplantation was performed to observed survival times. We demonstrated that triptolide markedly inhibited both the expression of CD80 and MHCII expression on DCs. Triptolide-modified DCs stimulated lower proliferative responses among allogeneic T cells, prolonging the survival of intestinal allografts in rats. These results suggested that pretreatment with triptolide-modified DC prolonged the survival of rat small bowel allografts after transplantation.

Caseinolytic protease: a protein vaccine which could elicit serotype-independent protection against invasive pneumococcal infection

Invasive pneumococcal diseases incur significant mortality, morbidity and economic costs. The most effective strategy currently available to reduce the burden of these diseases is vaccination. In this study, we evaluated the protective efficacy of immunizing mice with caseinolytic protease (ClpP) protein antigen whose gene sequences were shown to be highly conserved in different strains of Streptococcus pneumoniae in an invasive-disease model (intraperitoneal infection model), and protection against invasive challenge with 12 different serotypes of S. pneumoniae was assessed in two murine strains. Our findings demonstrated that active immunization with ClpP and passive immunization with antibodies specific for ClpP could elicit serotype-independent protection effectively against invasive pneumococcal infection. Therefore, to our knowledge, this study is the first report that immunization with single pneumococcal ClpP protein antigen could protect against such broad-range pneumococal strains, which thus supports the development of ClpP as a human penumococcal vaccine.

The Effect of Signal Quality on Six Cardiac Output Estimators

The effect of signal quality on the accuracy of cardiac output (CO) estimation from arterial blood pressure (ABP) was evaluated using data from the MIMIC II database. Thermodilution CO (TCO) was the gold standard. A total of 121 records with 1,497 TCO measurements were used. Six lumped-parameter and systolic area CO estimators were tested, using ABP features and a robust heart rate (HR) estimate. Signal quality indices for ABP and HR were calculated using previously described metrics. For retrospective analysis, results showed that the Liljestrand method yielded the lowest error for all levels of signal quality. Increasing signal quality decreased error and only marginally reduced the amount of available data, as a signal quality level of 90% preserved sufficient data for almost continuous CO estimation. At the recommended signal quality thresholds, the lowest gross root mean square normalized error (RMSNE) was found to be 15.4% (or 0.74 L/min) and average RMSNE was 13.7% (0.71 L/min).

Computer simulation comparison of tripolar, bipolar, and spline Laplacian electrocadiogram estimators

A comparison of the performance of the tripolar and bipolar concentric as well as spline Laplacian electrocardiograms (LECGs) and body surface Laplacian mappings (BSLMs) for localizing and imaging the cardiac electrical activation has been investigated based on computer simulation. In the simulation a simplified eccentric heart-torso sphere-cylinder homogeneous volume conductor model were developed. Multiple dipoles with different orientations were used to simulate the underlying cardiac electrical activities. Results show that the tripolar concentric ring electrodes produce the most accurate LECG and BSLM estimation among the three estimators with the best performance in spatial resolution.

Tailoring the photoluminescence of ZnO nanowires using Au nanoparticles

Rational design of hybrid nanostructures through attaching nanowires with nanoparticles is an effective route to enhance the existing functionalities or to explore new ones. We carry out a systematic investigation on the photoluminescence of ZnO nanowire-Au nanoparticle hybrid nanostructures synthesized by attaching Au nanoparticles onto ZnO nanowires. Citrate-stabilized 40 nm Au nanoparticles effectively quench the green emission and enhance the UV emission of the ZnO nanowires, which is consistent with the wavelength-dependent generation of surface plasmon. The UV/green emission intensity ratio could be reversibly and reproducibly tailored by attaching/detaching Au nanoparticles. This enhancement of UV emission diminishes if the Au nanoparticles are coated with a polymer layer. We also find that the orange-red emission of the ZnO nanowires is related to the excess oxygen on the ZnO surface, and it is also tunable via annealing and surface modifications.

Selenocystine induces apoptosis of A375 human melanoma cells by activating ROS-mediated mitochondrial pathway and p53 phosphorylation

Selenocystine (SeC), a naturally occurring selenoamino acid, has been shown to be a novel compound with broad-spectrum anticancer activity. In this study, we showed that SeC triggered time- and dose-dependent apoptosis in A375 human melanoma cells by activating the mitochondria-mediated and death receptor-mediated apoptosis pathways. Pretreatment of cells with a general caspase inhibitor z-VAD-fmk significantly prevented SeC-induced apoptosis. A375 cells exposed to SeC showed an increase in levels of total p53 and phosphorylated p53 (serine-15). Silencing of p53 expression with RNA interference significantly suppressed SeC-induced p53 phosphorylation, caspase activation and apoptotic cell death. Moreover, generation of reactive oxygen species and subsequent induction of DNA strand breaks were found to be upstream mediators of p53 activation induced by SeC. In a nude mice xenograft experiment, SeC significantly inhibited the tumor growth of A375 cells via induction of apoptosis. Taken together, these results suggest the potential applications of SeC in cancer chemoprevention.

Latent Tree Models and Approximate Inference in Bayesian Networks

We propose a novel method for approximate inference in Bayesian networks (BNs). The idea is to sample data from a BN, learn a latent tree model (LTM) from the data offline, and when online, make inference with the LTM instead of the original BN. Because LTMs are tree-structured, inference takes linear time. In the meantime, they can represent complex relationship among leaf nodes and hence the approximation accuracy is often good. Empirical evidence shows that our method can achieve good approximation accuracy at low online computational cost.

The application of MR brain surface anatomy scanning in the operation of intracranial parasagittal meningiomas

PURPOSE

To assess the usefulness of magnetic resonance (MR) brain surface anatomy scanning (SAS) in neurosurgery for intracranial parasagittal meningiomas.

METHODS AND MATERIALS

Pre-operative MR brain SAS was performed on 22 patients who underwent operations for intracranial parasagittal meningiomas. The tumour, the sagittal sinus and parasagittal circumflex veins adjacent to the tumour were examined.

RESULTS

For all 22 patients, the locations and extensions of brain surface parasagittal circumflex veins observed from MR brain SAS images correlated well with operative findings. Brain surface circumflex veins were preserved completely for 17 patients, in four patients tumour-related brain surface circumflex veins were resected, and in one patient brain surface circumflex veins crossing over the tumour surface were resected. No post-operative oedema or injury in nervous function was found in these patients, hence satisfying surgical outcomes were obtained.

CONCLUSION

MR brain SAS is able to clearly delineate brain surface circumflex veins which are close to parasagittal meningiomas, give an appropriate pre-operative evaluation, and provide instructive suggestions for the preservation or resection of veins on the tumour surface during the operation. It has great significance in the prevention of postoperative vasogenic oedema due to the dysfunction of vein circumfluence and the further neuro-dysfunction due to brain oedema. Consequently the surgical outcome can be improved and post-operative complications can be reduced.

Paramagnetic hyperfine splitting in the Eu Mössbauer spectra of CaF(2):Eu

(151)Eu Mössbauer spectra in zero magnetic field of highly dilute (0.1 mol%) Eu(2+) ions in CaF(2) showed an almost temperature-independent asymmetrically split pattern, arising from the paramagnetic hyperfine interaction AS. I in a cubic crystal field with slow electron spin relaxation; in a small external magnetic field B of 0.2 T such that gμ(B)B>A an almost symmetrical pattern was observed. Both the spectra with and without external field are well described using the spin Hamiltonian and previous electron paramagnetic resonance data. A more concentrated (2 mol% Eu(2+)) sample exhibited a strongly broadened symmetrical resonance line due to an increased Eu-Eu spin relaxation rate; in an external magnetic field of 0.2 T the Mössbauer spectra exhibited further broadening and additional magnetic structures due to the reduced relaxation rate. When a large field of 6 T was applied such that gμ(B)B is much larger than the crystal field splitting, a fully resolved hyperfine pattern was observed at 2.5 K, with an effective field at the Eu nuclei of -33.7 T; at higher temperatures superimposed patterns originating from excited electronic states were observed in the spectra. The present results on the highly dilute CaF(2) : 0.1%Eu(2+) sample deliver a straightforward explanation for previous observations of a seemingly large dependence of the Eu(2+) isomer shift on europium concentration.