Novel role of PAF1 in attenuating radiosensitivity in cervical cancer by inhibiting IER5 transcription.

BACKGROUND: Radiosensitivity is limited in cervical cancer (CC) patients due to acquired radiation resistance. In our previous studies, we found that immediate-early response 5 (IER5) is upregulated in CC cells upon radiation exposure and decreases cell survival by promoting apoptosis. The details on the transcriptional regulation of radiation-induced IER5 expression are unknown. Studies in recent years have suggested that Pol II-associated factor 1 (PAF1) is a pivotal transcription factor for certain genes "induced" during tumor progression. In this study, we investigated the role of PAF1 in regulating IER5 expression during CC radiotherapy. METHODS: PAF1 expression in CC cells was measured by western blotting, immunohistochemistry, and qRT-PCR, and the localization of PAF1 and IER5 was determined by immunofluorescence. The effect of PAF1 and IER5 knockdown by siRNA in Siha and Hela cells was studied by western blotting, qRT-PCR, CCK-8 assay, and flow cytometry. The physical interaction of PAF1 with the IER5 promoter and enhancers was confirmed using chromatin immunoprecipitation and qPCR with or without enhancers knockout by CRISPR/Cas9. RESULTS: We confirmed that PAF1 was highly expressed in CC cells and that relatively low expression of IER5 was observed in cells with highly expressed PAF1 in the nucleus. PAF1 knockdown in Siha and Hela cells was associated with increased expression of IER5, reduced cell viability and higher apoptosis rate in response to radiation exposure, while simultaneous PAF1 and IER5 knockdown had little effect on the proportion of apoptotic cells. We also found that PAF1 hindered the transcription of IER5 by promoting Pol II pausing at the promoter-proximal region, which was primarily due to the binding of PAF1 at the enhancers. CONCLUSIONS: PAF1 reduces CC radiosensitivity by inhibiting IER5 transcription, at least in part by regulating its enhancers. PAF1 might be a potential therapeutic target for overcoming radiation resistance in CC patients.

Ultrasensitive Assay of Alkaline Phosphatase Based on the Fluorescent Response Difference of the Metal-Organic Framework Sensor.

The assay of alkaline phosphatase (ALP) is important in clinical diagnosis because the abnormal expression of this enzyme is related to many serious diseases. In this work, using a luminescent metal-organic framework (MOF) as the sensor, a fluorescent method was developed for the activity assay of ALP. With nanoscale particle size, the prepared MOF sensor exhibited good dispersability and stable photoluminescence in aqueous suspension. The emission of this MOF is inert to p-nitrophenylphosphate (NPP) but could be efficiently quenched by its dephosphorylated product, p-nitrophenol. Taking advantage of this feature, this MOF was added to the system of ALP-catalyzed NPP dephosphorylation to transduce the proceeding of the reaction real-timely to the fluorescent signal. The enzyme activity could be calculated based on the recorded kinetic trace. This method presented a low detection limit (2 × 10-3 U L-1) and a wide quantification range (0.6-90 U L-1) in our experiments, showing its quantification capability challenges the best of current ALP analytical methods. As a practical application, our method was successfully applied to the ALP analysis in human serum samples.

Metal-organic frameworks based fluorescent sensor array for discrimination of flavonoids.

Metal-organic frameworks (MOFs) are hotly investigated as a novel kind of fluorescent sensing materials in recent years. However, the application of MOF sensing to drug analysis is still very difficult yet, because the structural similarity among drug homolog-ues exceeds the discrimination ability of MOFs. Array sensing technique, which relies on the combined responses of a group of sensing materials, is a viable way to solve this problem. In this work, we chose five luminescent MOFs with different fluorophores to construct a fluorescent sensor array for the analysis of flavonoids. With the response pattern of these MOFs and the statistical methods of linear discriminant analysis and hierarchical cluster analysis, nine flavonoids with similar structures were correctly discriminated. By the combination with UV spectrum, our method could even realize the qualification and quantification of the flavonoid samples with unknown concentrations. This work is the first time of using MOFs to successfully distinguish multiple drug homolog-ues.

Pyrene-based MOFs as fluorescent sensors for PAHs: an energetic pathway of the backbone structure effect on response.

The sensing performance of metal-organic frameworks (MOFs), a novel kind of crystalline fluorescent sensing materials, would be profoundly affected by their backbone structures. The current understanding about the backbone effect is limited to the modulation of analyte accommodation through pore structures. Herein, three topologically different pyrene-based MOFs, including NU-1000, NU-901 and ROD-7, were investigated as potential fluorescent sensors for polycyclic aromatic hydrocarbons (PAHs). Although these MOFs are constructed by the same photoactive component, they exhibited distinct sensing behaviors. NU-1000 gave different forms of fluorescent response to acenaphthylene, pyrene and fluoranthene with detection limits at the ng L-1 level. In contrast, NU-901 and ROD-7 were unresponsive to all tested PAHs. Experimental and computational investigations illustrate that this distinction is due to the variance in the excited state energy. The strong inter-ligand interaction in NU-901 and ROD-7 lowers their excited state energy and thus thermodynamically inhibits the photo-induced electron transfer and excimer/exciplex formation, which works in the NU-1000 system. This work proves for the first time that the topological structure of MOFs could affect their sensing performance in an energetic way.

Metal-organic framework-based fluorescent sensing of tetracycline-type antibiotics applicable to environmental and food analysis.

Antibiotics have been noted as an important class of emerging contaminants in the environment. Metal-organic frameworks (MOFs), which have been intensely investigated as a novel kind of sensing material, have been tentatively applied to the detection of antibiotics in recent years. In this work, a nanoscale MOF (In-sbdc) with a strong (quantum yield = 13%) and stable emission in water was synthesized. With its effective spectral overlap with tetracyclines, adsorption preconcentration and the usage of a masking agent, In-sbdc gave sensitive responses to a series of tetracycline antibiotics (tetracycline, chlorotetracycline and oxytetracycline) with detection limits of 0.28-0.30 µM, but another eight tested kinds of antibiotics did not cause a remarkable change in its emission (<10% of the response caused by an equal amount of tetracyclines). This MOF-based sensing system was successfully applied to tetracyclines detection in a series of actual water and food samples.

MOF based fluorescent assay of xanthine oxidase for rapid inhibitor screening with real-time kinetics monitoring.

The activity assay of xanthine oxidase (XO) is of great application value in clinical diagnosis because the abnormal level of this enzyme is related to a series of pathological states. In this work, a Zr based metal-organic framework (BTB-MOF) with stable photoluminescence in pure water and buffer solution was synthesized. The examination about the fluorescent responses of this material to xanthine and its oxidation product, uric acid, showed that, although both of them affected the emission of BTB-MOF in quenching form, the efficiencies presented much difference. Taking advantage of this feature, a fluorescent method was developed for the activity assay of XO, that is, BTB-MOF was added to the enzymatic oxidation system as a sensor to transduce the proceeding of the reaction real-timely to the signal of fluorescent intensity change. Our method can work under the interference of normal biologically related species, and precisely reflect XO activity in the range of 0.2-40 U L-1 (detection limit = 0.004 U L-1). With consecutive fluorescence intensity scan, this assay could be applied as a high speed screening method of XO inhibitors with the testing time of 1 min. This work shows the wide potential application of MOFs in enzyme analysis.

[Study of the radiotherapy modality for patients with stage IIb-IIIb cervical stump cancer].

OBJECTIVE: To investigate the radiotherapy modality progress of stageIIb-IIIb cervical stump cancer. METHODS: The clinical data of 13 patients with stageIIb-IIIb cervical stump cancer undergoing radiotherapy from January 2000 to April 2012 was reviewed. Before 2006, 8 patients received conventional external beam radiotherapy and brachytherapy.Since 2006, 5 patients received intensity-modulated radiotherapy (IMRT) and brachytherapy. RESULTS: The median survival was 12-139 months. The median overall survivals and disease free survivals in the conventional radiotherapy (CRT) group were 57 months and 50 months, 3 cases of them recurred during 8-19 months and died of tumor progression.While, the median overall survivals and disease free survival in the IMRT group both were 21 months and nobody recurred. In the CRT group, 7 patients suffered toxicities, including 5 patients grade I-II acute rectum reaction, 2 patients grade I bladder reaction; and 3 had grade I-III, late rectum reaction, 2 patients for grade II bladder late reaction.In the IMRT group, toxicities including 1 case grade I acute or late rectum reaction, and no bladder reaction. CONCLUSION: In our experience, the recommended IMRT and interstitial brachytherapy for the selected patients with advanced cervical stump carcinoma may be obtain better tumor dose distribution and more sparing of the organ at risk.

[Photosynthetic characteristics of Drynaria fortunei and its relation to environmental factors].

OBJECTIVE: To have a better utilization of diurnal photosynthetic variation of Drynaria fortunei in three light environments and provide theoretical basis for its artificial cultivation. METHODS: Diurnal photosynthetic variation of Drynaria fortunei were determinated by portable photosynthesis analysis system (Li-6400), and correlation between physiological and environmental factors was further analysed. RESULTS: The diurnal net photosynthetic rate (NPR) exhibited a single peak curve, with the peak value of NPR occurring at 15:30. The mean diurnal Pn of D. fortunei in three environments followed a tread of tree epiphytes > shine > shade. WUE had significantly positive correlation with NPR. Air temperature (Ta), ambient CO2 concentration (Ca) and relative humidity (RH) were the main environmental factors for NPR of D. fortunei. CONCLUSION: The optimum cultivation condition of D. fortunei is 32 degrees C, RH around 40%, and appropriate shade is recommended.