Detection of the mesenchymal-to-epithelial transition of invasive non-small cell lung cancer cells by their membrane undulation spectra

A cancer cell changes its state from being epithelial- to mesenchymal-like in a dynamic manner during tumor progression. For example, it is well known that mesenchymal-to-epithelial transition (MET) is essential for cancer cells to regain the capability of seeding on and then invading secondary/tertiary regions. However, there is no fast yet reliable method for detecting this transition. Here, we showed that membrane undulation of invasive cancer cells could be used as a novel marker for MET detection, both in invasive model cell lines and repopulated circulating tumor cells (rCTCs) from non-small cell lung cancer (NSCLC) patients. Specifically, using atomic force microscopy (AFM), it was found that the surface oscillation spectra of different cancer cells, after undergoing MET, all exhibited two distinct peaks from 0.001 to 0.007 Hz that are absent in the spectra before MET. In addition, by adopting the long short-term memory (LSTM) based recurrent neural network learning algorithm, we showed that the positions of recorded membrane undulation peaks can be used to predict the occurrence of MET in invasive NSCLC cells with high accuracy (>90% for model cell lines and >80% for rCTCs when benchmarking against the conventional bio-marker vimentin). These findings demonstrate the potential of our approach in achieving rapid MET detection with a much reduced cell sample size as well as quantifying changes in the mesenchymal level of tumor cells.

A retrospective study of traumatic dental injuries in primary dentition: treatment outcomes of splinting

OBJECTIVE

Splinting in primary dentition is limited to several traumatic dental injuries. The prognosis associated with splint use has not been fully investigated. In this study, we investigated the outcomes of traumatic injuries in primary teeth treated with splinting.

MATERIALS AND METHODS

We retrospectively analysed 137 children with root fractures and lateral and extrusive luxation injuries to their primary teeth who were treated with semi-rigid splints between 2010 and 2016. Treatment outcomes were analysed in patients with follow-up periods of >6 months. The outcomes of splinting were based on clinical and radiographic evaluations performed during follow-up examinations.

RESULTS

In total, 182 primary teeth were examined, and of these, 90 teeth were treated using semi-rigid splints. In the splint group, pathological root resorption (31.1%) was the most common complication, whereas pathological tooth loss (25.0%) was found most common in the observation group. Splinting in root fractures showed a good prognosis, whereas in lateral and extrusive luxations, it did not (p < .05). There were no relationship between treatment delay and prognosis (p > .05).

CONCLUSIONS

Depending on the type of luxation, splint therapy results in acceptable outcomes and may be a feasible treatment option.

Cadherin- and Rigidity-Dependent Growth of Lung Cancer Cells in a Partially Confined Microenvironment

During tumor development, cancer cells constantly confront different types of extracellular barriers. However, fundamental questions like whether tumor cells will continue to grow against confinement or away from it and what key factors govern this process remain poorly understood. To address these issues, here we examined the growth dynamics of human lung epithelial carcinoma A549 cells partially confined in micrometer-sized cylindrical pores with precisely controlled wall stiffness. It was found that, after reaching confluency, the cell monolayer enclosed by a compliant wall was able to keep growing and pushing the boundary, eventually leading to a markedly enlarged pore. In contrast, a much reduced in-plane growth and elevated strain level among cells were observed when the confining wall becomes stiff. Furthermore, under such circumstance, cells switched their growth from within the monolayer to along the out-of-plane direction, resulting in cell stacking. We showed that these observations can be well explained by a simple model taking into account the deformability of the wall and the threshold stress for inhibiting cell growth. Interestingly, cadherins were found to play an important role in the proliferation and stress buildup within the cell monolayer by aggregating at cell-cell junctions. The stiff confinement led to an elevated expression level of cadherins. Furthermore, inhibition of N-cadherin resulted in a significantly suppressed cell growth under the same confining conditions.

A future of cancer prevention and cures: highlights of the Centennial Meeting of the American Association for Cancer Research

The Centennial Meeting of the American Association for Cancer Research (AACR) was held from 14-18 April 2007 at the Los Angeles Convention Center. This meeting brought together a diverse group of over 18 000 researchers working in the fields of basic and applied cancer sciences, and explored how cancer research could be used most effectively to prevent and cure cancer at the earliest possible stage. The goal of the AACR Annual Meeting was to stimulate the dialog between basic and clinical researchers so that the translation of new discoveries might be speeded up for the benefit of cancer patients. Advances in the clinical application of genomics, epigenomics and proteomics to diagnose, monitor and prognosticate cancer development led to a dramatic increase in the number of presentations with a translational focus at this year's meeting. Several remarkable areas were particularly highlighted in this report, including The Cancer Genome Atlas, cancer stem cells, microRNA and siRNA, targeted therapy and individualized treatment. This article tries to bring attention to some hot topics in the program that are both new and noteworthy. For those who did not attend the meeting, this report may serve as a highlight of this important international cancer research meeting.

Remarkable application of serum EBV EBER-1 in monitoring response of nasopharyngeal cancer patients to salvage chemotherapy

Nineteen consecutive patients with metastatic or recurrent nasopharyngeal cancer (NPC) receiving combination chemotherapy were monitored for EBV DNA in their serum. EBV DNA (EBER-1) concentration in serum was measured before, during, and after chemotherapy. Thirteen patients had additional multiple prechemotherapy readings. There was a significant lead time from first detection of serum EBER-1 to clinical recurrence in 62% of patients by a mean of 17.4 weeks (range: 8-74.5 weeks; mean = 28.2 weeks if confined to the 8 patients with significant lead time). The median EBER-1 concentration was significantly higher in those with distant metastasis as compared to those with loco-regional recurrence only (17,468 vs. 684 pg/mL serum; p = 0.046, Mann-Whitney U test). Among the 13 patients who responded to chemotherapy, 4 exhibited clinical complete remission (CR) who were only found in the group with EBER-1 DNA drop to background level, while the magnitude of EBER-1 drop did not discriminate partial remission (PR) and stable disease (SD) patients clearly. Subsequent profile of EBER-1 DNA showed concordance with clinical course of either continuous remission or later progression. EBER-1 DNA in serum can become a useful adjunctive surrogate marker to monitor chemotherapeutic response in NPC patients with distant metastasis or advanced local recurrence.

Pilot fragile X screening in normal population of Taiwan

Fragile X syndrome (FXS) is the most common hereditary form of mental retardation. Molecular analysis of the FMR1 gene has now been applied to diagnosis and carrier detection. Because treatment is not feasible, prevention of FXS by prenatal diagnosis of carrier women early during pregnancy is important. The aim of this pilot study was to ascertain the prevalence of mutant FMR1 gene in normal population of Taiwan and to evaluate the efficacy of a betaine-based polymerase chain reaction (PCR) and nonradioactive Southern blot assays. The DNA was randomly and anonymously collected from 100 women and 100 men. The results showed 62% of the women were heterozygous for the CGG-repeat size in FMR1 gene. One of 300 X chromosomes in this study showed premutation, with 95 CGG repeats. All other chromosomes have CGG repeats ranging from 19 to 52, with eight chromosomes (3%) having more than 40 CGG repeats. The most prevalent allele has 29 repeats (48.1%), followed by 30 (24.0%) and 36 (9.5%), respectively. The results of this study reconfirmed previous reports that the prevalent FMR1 CGG repeat alleles in Chinese population are different from that of other populations. However, the prevalence of premutation gene seems to be comparable among them. The betaine-based PCR could minimize the intrinsic problem of preferential amplification and may reliably determine the different allele repeats in heterozygous females. This nonradioactive Southern blot protocol is safe, efficient, and inexpensive. However, further technical improvement may be needed to be more cost-effective for a wide screening of all pregnant women.