DCE-MRI for Pre-Treatment Prediction and Post-Treatment Assessment of Treatment Response in Sites of Squamous Cell Carcinoma in the Head and Neck

Background and Purpose

It is important to identify patients with head and neck squamous cell carcinoma (SCC) who fail to respond to chemoradiotherapy so that they can undergo post-treatment salvage surgery while the disease is still operable. This study aimed to determine the diagnostic performance of dynamic contrast enhanced (DCE)-MRI using a pharmacokinetic model for pre-treatment predictive imaging, as well as post-treatment diagnosis, of residual SCC at primary and nodal sites in the head and neck.

Material and Methods

Forty-nine patients with 83 SCC sites (primary and/or nodal) underwent pre-treatment DCE-MRI, and 43 patients underwent post-treatment DCE-MRI, of which 33 SCC sites had a residual mass amenable to analysis. Pre-treatment, post-treatment and % change in the mean K^trans, k_ep, v_e and AUGC were obtained from SCC sites. Logistic regression was used to correlate DCE parameters at each SCC site with treatment response at the same site, based on clinical outcome at that site at a minimum of two years.

Results

None of the pre-treatment DCE-MRI parameters showed significant correlations with SCC site failure (SF) (29/83 sites) or site control (SC) (54/83 sites). Post-treatment residual masses with SF (14/33) had significantly higher k_ep (p = 0.05), higher AUGC (p = 0.02), and lower % reduction in AUGC (p = 0.02), than residual masses with SC (19/33), with the % change in AUGC remaining significant on multivariate analysis.

Conclusion

Pre-treatment DCE-MRI did not predict which SCC sites would fail treatment, but post-treatment DCE-MRI showed potential for identifying residual masses that had failed treatment.     

Inhibition of S/G2 phase CDK4 reduces mitotic fidelity

Cyclin-dependent kinase 4 (CDK4)/cyclin D has a key role in regulating progression through late G(1) into S phase of the cell cycle. CDK4-cyclin D complexes then persist through the latter phases of the cell cycle, although little is known about their potential roles. We have developed small molecule inhibitors that are highly selective for CDK4 and have used these to define a role for CDK4-cyclin D in G(2) phase. The addition of the CDK4 inhibitor or small interfering RNA knockdown of cyclin D3, the cyclin D partner, delayed progression through G(2) phase and mitosis. The G(2) phase delay was independent of ATM/ATR and p38 MAPK but associated with elevated Wee1. The mitotic delay was because of failure of chromosomes to migrate to the metaphase plate. However, cells eventually exited mitosis, with a resultant increase in cells with multiple or micronuclei. Inhibiting CDK4 delayed the expression of the chromosomal passenger proteins survivin and borealin, although this was unlikely to account for the mitotic phenotype. These data provide evidence for a novel function for CDK4-cyclin D3 activity in S and G(2) phase that is critical for G(2)/M progression and the fidelity of mitosis.     

Synthesis and biological evaluation of benzyl styrylsulfonyl derivatives as potent anticancer mitotic inhibitors

We herein report the synthesis, biological activity and structure activity relationship of derivatives of benzylstyrylsulfone, benzylstyrylsulfine and benzylsulfonyl-N-phenylacetamide. A lead compound 7 represents a new class of mitotic inhibitors that demonstrates potent anti-proliferative activity and selectively induces cancer cell apoptosis while sparing non-transformed lung fibroblast.     

Carbon Dioxide and Methane Emissions from Peat Soil in an Undrained Tropical Peat Swamp Forest

Ecosystems - This study investigates the factors controlling the soil CO2 and CH4 fluxes and quantifies annual cumulative soil respiration (RS), heterotrophic respiration (RH), and soil CH4...     

Genetic Diversity and Natural Selection of the Plasmodium knowlesi Circumsporozoite Protein Nonrepeat Regions

Background

Plasmodium knowlesi is a simian malaria parasite that has been identified to cause malaria in humans. To date, several thousand cases of human knowlesi malaria have been reported around Southeast Asia. Thus far, there is no detailed study on genetic diversity and natural selection of P. knowlesi circumsporozoite protein (CSP), a prominent surface antigen on the sporozoite of the parasite. In the present study, the genetic diversity and natural selection acting on the nonrepeat regions of the gene encoding P. knowlesi CSP were investigated, focusing on the T-cell epitope regions at the C-terminal of the protein.

Methods

Blood samples from 32 knowlesi malaria patients and 2 wild monkeys (Macaca fascicularis) were used. The CSP of the P. knowlesi isolates was amplified by PCR, cloned into Escherichia coli, and sequenced. The nonrepeat regions of the CSP gene were analysed for genetic diversity, natural selection and haplotypic grouping using MEGA5 and DnaSP version 5.10.00 programmes. A haplotype network was constructed based on the C-terminal (Th2R/Th3R) T-cell epitope regions using the Median-Joining method in the NETWORK version 4.6.1.2 programme. Previously published sequences from other regions (Malaysia Borneo, Singapore) were also included in the analysis.

Results

A total of 123 P. knowlesi CSP sequences were analysed. Multiple sequence alignment revealed 58 amino acid changes, and 42 novel amino acid haplotypes were identified. Polymorphism was higher in the C-terminal Th2R/Th3R epitope (π = 0.0293, n = 123) region compared to the overall combined nonrepeat regions (π = 0.0120, n = 123). Negative natural selection was observed within the nonrepeat regions of the CSP gene. Within the C-terminal Th2R/Th3R epitope regions, there was evidence of slight positive selection. Based on haplotype network analysis of the Th2R/Th3R regions, five abundant haplotypes were identified. Sharing of haplotypes between humans and macaques were observed.

Conclusion

This study contributes to the understanding of the type and distribution of naturally occurring polymorphism in the P. knowlesi CSP gene. This study also provides a measurement of the genetic diversity of P. knowlesi and identifies the predominant haplotypes within Malaysia based on the C-terminal Th2R/Th3R regions.     

Cell Line Derived Multi-Gene Predictor of Pathologic Response to Neoadjuvant Chemotherapy in Breast Cancer: A Validation Study on US Oncology 02-103 Clinical Trial

Background

Massively-parallel sequencing (MPS) technologies create challenges for informed consent of research participants given the enormous scale of the data and the wide range of potential results.

Discussion

We propose that the consent process in these studies be based on whether they use MPS to test a hypothesis or to generate hypotheses. To demonstrate the differences in these approaches to informed consent, we describe the consent processes for two MPS studies. The purpose of our hypothesis-testing study is to elucidate the etiology of rare phenotypes using MPS. The purpose of our hypothesis-generating study is to test the feasibility of using MPS to generate clinical hypotheses, and to approach the return of results as an experimental manipulation. Issues to consider in both designs include: volume and nature of the potential results, primary versus secondary results, return of individual results, duty to warn, length of interaction, target population, and privacy and confidentiality.

Summary

The categorization of MPS studies as hypothesis-testing versus hypothesis-generating can help to clarify the issue of so-called incidental or secondary results for the consent process, and aid the communication of the research goals to study participants.     

Microbiological Culture Simplified Using Anti-O12 Monoclonal Antibody in TUBEX Test to Detect Salmonella Bacteria from Blood Culture Broths of Enteric Fever Patients

Definitive diagnosis of infectious diseases, including food poisoning, requires culture and identification of the infectious agent. We described how antibodies could be used to shorten this cumbersome process. Specifically, we employed an anti-Salmonella lipopolysaccharide O12 monoclonal antibody in an epitope-inhibition 10-min test (TUBEX TP) to detect O12⁺ Salmonella organisms directly from routine blood culture broths. The aim is to obviate the need to subculture the broth and subsequently identify the colonies. Thus, blood from 78 young outpatients suspected of having enteric fever was incubated in an enrichment broth, and after 2 or 4 days, broth samplings were examined by TUBEX TP as well as by conventional agar culture and identification. TUBEX TP was performed before the culture results. Eighteen isolates of S. Typhi (15 after 2 days) and 10 isolates of S. Paratyphi A (4 after 2 days) were obtained by conventional culture. Both these Salmonella serotypes, the main causes of enteric fever, share the O12 antigen. In all instances where either of these organisms was present (cultured), TUBEX TP was positive (score 4 [light blue] – to – score 10 [dark blue]; negative is 0 [pink-colored]) i.e. 100% sensitive. Identification of the specific Salmonella serotype in TUBEX-positive cases was achieved subsequently by conventional slide agglutination using appropriate polyclonal antisera against the various serotypes. Twelve Escherichia coli, 1 Alcaligenes spp. and 1 Enterobacter spp. were isolated. All of these cases, including all the 36 culture-negative broths, were TUBEX-negative i.e. TUBEX TP was 100% specific. In a separate study using known laboratory strains, TUBEX TF, which detects S. Typhi but not S. Paratyphi A via the O9 antigen, was found to efficiently complement TUBEX TP as a differential test. Thus, TUBEX TP and TUBEX TF are useful adjuncts to conventional culture because they can save considerable time (>2 days), costs and manpower.     

Mechanistic insight into heterogeneity of trans-plasma membrane electron transport in cancer cell types

Trans-plasma membrane electron transfer (tMPET) is a process by which reducing equivalents, either electrons or reductants like ascorbic acid, are exported to the extracellular environment by the cell. TPMET is involved in a number of physiological process and has been hypothesised to play a role in the redox regulation of cancer metabolism. Here, we use a new electrochemical assay to elucidate the ‘preference’ of cancer cells for different trans tPMET systems. This aids in proving a biochemical framework for the understanding of tPMET role, and for the development of novel tPMET-targeting therapeutics. We have delineated the mechanism of tPMET in 3 lung cancer cell models to show that the external electron transfer is orchestrated by ascorbate mediated shuttling via tPMET. In addition, the cells employ a different, non-shuttling-based mechanism based on direct electron transfer via Dcytb. Results from our investigations indicate that tPMETs are used differently, depending on the cell type. The data generated indicates that tPMETs may play a fundamental role in facilitation of energy reprogramming in malignant cells, whereby tPMETs are utilised to supply the necessary energy requirement when mitochondrial stress occurs. Our findings instruct a deeper understanding of tPMET systems, and show how different cancer cells may preferentially use distinguishable tPMET systems for cellular electron transfer processes.