The cell cycle is the process by which eukaryotic cells replicate. Yeast cells cycle asynchronously with each cell in the population budding at a different time. Although there are several ...experimental approaches to synchronise cells, these usually work only in the short-term. Here, we build a cyber-genetic system to achieve long-term synchronisation of the cell population, by interfacing genetically modified yeast cells with a computer by means of microfluidics to dynamically change medium, and a microscope to estimate cell cycle phases of individual cells. The computer implements a controller algorithm to decide when, and for how long, to change the growth medium to synchronise the cell-cycle across the population. Our work builds upon solid theoretical foundations provided by Control Engineering. In addition to providing an avenue for yeast cell cycle synchronisation, our work shows that control engineering can be used to automatically steer complex biological processes towards desired behaviours similarly to what is currently done with robots and autonomous vehicles.
Background
Although surgery is the gold standard treatment of hepatic metastasis from colorectal cancer (CRC), many patients ultimately die of their disease. We tested the hypothesis that the ...detection of circulating tumor cells (CTC) might identify patients at high risk of dying of disease recurrence after apparently radical liver surgery.
Methods
We considered 50 patients undergoing radical surgery for liver-confined hepatic metastasis from CRC. The expression of a panel of cancer-related genes, as assessed by quantitative real-time PCR, was used to detect CTC in the peripheral blood of these patients immediately before surgery. Survival analysis was performed by the Cox regression model.
Results
Univariate analysis of the expression levels of CD133 (a marker of colon cancer stem cells) and survivin (an antiapoptotic factor) resulted in statistically significant association with patient survival hazard ratio (HR) 2.7, 95% confidence interval (CI) 1.9–3.7,
P
< 0.0001; and hazard ratio 2.1, 95% CI 1.4–3.2,
P
< 0.0001, respectively. Remarkably, multivariate analysis found that only the transcriptional amount of CD133 resulted in statistical significance (HR 2.6, 95% CI 1.9–3.6,
P
< 0.0001), indicating that this biomarker can independently predict the survival of these patients.
Conclusions
CD133-positive CTC may represent a suitable prognostic marker to stratify the risk of patients who undergo liver resection for CRC metastasis, which opens the avenue to identifying and potentially monitoring the patients who are most likely to benefit from adjuvant treatments.
The diagnosis and follow-up of bladder cancer are mainly based on cystoscopy, an invasive method which could be negative in case of flat malignancies such as carcinoma in situ. Other noninvasive ...diagnostic methods have not yet given satisfactory results. There is a need for a reliable yet noninvasive method for the detection of bladder cancer. Our aim was to investigate whether cell-free DNA quantified in urine (ucf-DNA) could be a useful marker for the diagnosis of bladder cancer. A standard urine test was performed in 150 naturally voided morning urine samples that were processed to obtain a quantitative evaluation of ucf-DNA. Leukocyturia and/or bacteriuria were found in 18 subjects, who were excluded from the study. Statistical analysis was performed on 45 bladder cancer patients and 87 healthy subjects. Ucf-DNA was extracted from urine samples by a spin column-based method and quantified using four different methods: GeneQuant Pro (Amersham Biosciences, Pittsburg, PA, USA), Quant-iT DNA high-sensitivity assay kit (Invitrogen, Carlsbad, CA, USA), Real-Time PCR (Applied Biosystems, Foster City, CA, USA), and NanoDrop 1000 (NanoDrop Technologies, Houston, TX, USA). Median free DNA quantification did not differ statistically between bladder cancer patients and healthy subjects. A receiver-operating characteristic (ROC) curve was developed to evaluate the diagnostic performance of ucf-DNA quantification for each method. The area under the ROC curve was 0.578 for GeneQuant Pro, 0.573 for the Quant-iT DNA high-sensitivity assay kit, 0.507 for Real-Time PCR, and 0.551 for NanoDrop 1000, which indicated that ucf-DNA quantification by these methods is not able to discriminate between the presence and absence of bladder cancer. No association was found between ucf-DNA quantification and tumor size or tumor focality. In conclusion, ucf-DNA isolated by a spin column-based method and quantified by GeneQuant Pro, Quant-iT DNA high-sensitivity assay kit, Real-Time PCR or NanoDrop 1000 does not seem to be a reliable marker for the diagnosis of bladder cancer.
Micro-Abstract Neoadjuvant radiochemotherapy is the gold standard for locally advanced rectal cancer, but this strategy does not achieve benefit in all patients. Analysis of intracellular signal ...pathways in patients with locally advanced rectal cancer identified a phosphoproteomic profile that may cluster patients who do not respond to neoadjuvant chemoradiotherapy.
Increasing evidence suggests that common gene polymorphisms may influence the toxicity of various cytotoxic agents used in the treatment of cancer.
To evaluate the predictive value of acute toxicity ...of methylenetetrahydrofolate reductase 677T polymorphism, glutathione S-transferase P1 (GSTP1) substitution of isoleucine with valine at codon 105 (Ile105Val) polymorphism and the tandem repeat polymorphism in the thymidylate synthase gene promoter in elderly patients with rectal cancer receiving preoperative chemoradiotherapy (CRT).
From 1994 to 2002, 166 Caucasian patients underwent surgery following CRT for mid-low rectal cancer at a single institution, 42 (male-to-female ratio, 25 : 17) of whom were aged > or =65 years (median age 70 years, range 65-79). The pre-treatment clinical stage was tumour (T) stage 3-4 in 38 patients and node (N)-positive in 29 patients. Patients received external-beam radiotherapy with conventional fractionation and fluorouracil-based chemotherapy. Blood samples were used to extract and amplify DNA. Gene polymorphisms were determined by polymerase chain reaction and restriction enzyme digestion. Acute toxicity to preoperative therapy was reported according to the National Cancer Institute Common Toxicity Criteria, version 2. Univariate and multivariate analyses were performed using one-way analysis of variance and linear regression, respectively.
Haematological toxicity (grade 1-2) was observed in 15 of 40 patients for whom toxicity data were available and gastrointestinal toxicity (grade 1-4) in 24 of these same 40 patients. At univariate analysis, female sex (p = 0.036) and GSTP1 Ile105Val (p = 0.0376) were associated with haematological toxicity. At multivariate analysis, GSTP1 Ile105Val polymorphism (p = 0.041) was the only factor found to be associated with haematological toxicity. Patients carrying the Val/Val genotype in the GSTP1 gene had a lower risk of haematological toxicity (odds ratio = 0.322, 95% CI 0.101, 0.957) than patients with the Ile/Ile genotype.
GSTP1 Ile105Val polymorphism is a promising marker of potential haematological toxicity in elderly patients with rectal cancer receiving preoperative CRT.
Cancer is the consequence of intra- and extracellular signaling network deregulation that derives from alteration of genetic and proteomic cellular homeostasis. Mapping the individual molecular ...circuitry of a patient's tumor cells is the starting point for rational personalized therapy.While genes and RNA encode information about cellular status, proteins are considered the engine of the cellular machine, as they are the effective elements that drive cellular functions, such as proliferation, migration, differentiation, and apoptosis. Consequently, investigations of the cellular protein network are considered a fundamental tool to understand cellular functions. In the last decades, increasing interest has been focused on the improvement of new technologies for proteomic analysis. In this context, reverse-phase protein microarrays (RPMAs) have been developed to study and analyze posttranslational modifications that are responsible for principal cell functions and activities. This innovative technology allows the investigation of protein activation as a consequence of protein-protein interaction or biochemical reactions, such as phosphorylation, glycosylation, ubiquitination, protein cleavage, and conformational alterations.Intracellular balance is carefully conserved by constant rearrangements of proteins through the activity of a series of kinases and phosphatases. Therefore, knowledge of the key cellular signaling cascades reveal information regarding the cellular processes driving a tumor's growth (such as cellular survival, proliferation, invasion, and cell death) and response to treatment.Alteration to cellular homeostasis, driven by elaborate intra- and extracellular interactions, has become one of the most studied fields in the era of personalized medicine and targeted therapy. RPMA technology is a valid tool that can be applied to protein analysis of several diseases for the potential to generate protein interaction and activation maps that lead to the identification of critical nodes for individualized or combinatorial target therapy.
The periodic process of cell replication by division, known as cell-cycle, is a natural phenomenon occurring asynchronously in any cell population. Here, we consider the problem of synchronising ...cell-cycles across a population of yeast cells grown in a microfluidics device. Cells were engineered to reset their cell-cycle in response to low methionine levels. Automated syringes enable changing methionine levels (control input) in the microfluidics device. However, the control input resets only those cells that are in a specific phase of the cell-cycle (G1 phase), while the others continue to cycle unperturbed. We devised a simplified dynamical model of the cell-cycle, inferred its parameters from experimental data and then designed two control strategies: (i) an open-loop controller based on the application of periodic stimuli; (ii) a closed-loop model predictive controller (MPC) that selects the sequence of control stimuli which maximises a synchronisation index. Both the proposed control strategies were validated in-silico, together with experimental validation of the open-loop strategy.
Media that sexually objectify women by portraying them in ways that emphasize physical beauty and sexual readiness as well as reduce them to decorative and sexual objects have been traditionally ...identified by scholars as a powerful cultural risk factor encouraging sexual harassment and sexual violence. In the present article we review the existing empirical evidence linking sexually objectifying media and sexual harassment of women to the overarching and integrative Media-Induced Sexual Harassment framework. This framework offers a coherent scheme for explaining the effects of sexually objectifying media on three target groups directly involved in sexual harassment—perpetrators, victims, and bystanders—and it postulates three cognitive and emotional mechanisms through which sexually objectifying media lead to sexual harassment: dehumanization, disruption of emphatic resonance, and a shift in gender norms. The evidence reviewed on the basis of the Media-Induced Sexual Harassment framework shows that sexually objectifying media converge in normalizing harassing behaviors and can be a causal risk factor for increasing engagement in sexual harassment, heightening victims’ acceptance of sexual harassment and discouraging bystander intervention. We discuss implications of these arguments for effectively preventing negative effects of exposure to sexually objectifying media and for education programs aimed at critical media-consumption.
PDF
