The Effect of MDSC-Derived Exosomes Played in Esophageal Squamous Carcinoma Cells after Ionizing Radiation

PURPOSE/OBJECTIVE(S)

Radiotherapy is the main treatment for esophageal cancer. Previous studies have shown that radiotherapy not only kills tumor cells directly, but also reshapes the immune microenvironment of the tumor. It has been reported an increase in the recruitment of myeloid-derived suppressor cells (MDSC) can occur in tumor tissue after ionizing radiation. Exosomes are mediators of intercellular information exchange and are also involved in the regulation of the tumor microenvironment. In this study, we wanted to understand whether MDSC in esophageal cancer tissue are involved in the regulation of tumor cell response to ionizing radiation via exosomes.

MATERIALS/METHODS

KYSE-150 was used to construct a subcutaneous transplantation tumor model in nude mice. And then mice irradiated with 5 Gy×5fx and 0 Gy×5fx respectively. After irradiation, the spleens of the mice were used to isolate MDSC, and collect the cell supernatants to extract the exosomes. Based on the exosomes, we divided the experiment into three groups (control, exosomes, exosomes+radiation). Exosomes were injected into a nude mouse model of esophageal cancer via the tail vein or co-cultured with KYSE-150 cells. Mice were irradiated with a 5 Gy×5fx after completion of injection, and KYSE-150 cells were irradiated with a single dose 4 Gy. After radiation, KYSE-150 cells were used to detect cell cloning, apoptosis and cell cycle by flow cytometry, cell proliferation by CCK 8. XRCC4,XRCC5,XRCC6,γH2AX,ATM expression in cells and tumor tissue were measured by Western blot and RT-PCR.

RESULTS

The tumor volume was significantly reduced after 5 Gy x 5fx radiation. When exosomes co-cultured with KYSE-150 cells, decrease in apoptosis and increase in cell cloning and cell proliferation were found in the exosomes+radiation group and exosomes group after radiation when compared with the control group, with this change being more pronounced in the exosome+radiation group. The results of the cell cycle assay showed that after ionizing radiation, the proportion of cells in the G0/G1 phase was significantly lower, and the proportion of cells in the S and G2/M phases were significantly higher in the exosomes+radiation group and exosomes group when compared to the Control group. The protein and mRNA expression of XRCC4,XRCC5,XRCC6,γH2AX,ATM in cells were increased in exosomes+radiation group and exosomes group after radiation when compared with the control group, with this change being more obvious in the exosome+radiation group. After irradiation, tumor volumes were measured in nude mice and the results showed that exosomes+radiation group tumors were the largest in volume, while the control group regressed most significantly after irradiation.

CONCLUSION

MDSC-derived exosomes have a tumor growth-promoting effect in esophageal squamous carcinoma, which is enhanced by ionizing radiation, and this may be related to the accelerated repair of damage in tumor tissue after radiation.

Choroid Plexus Calcification Correlates with Cortical Microglial Activation in Humans: A Multimodal PET, CT, MRI Study

BACKGROUND AND PURPOSE

The choroid plexus (CP) within the brain ventricles is well-known to produce cerebrospinal fluid (CSF). Recently, the CP has been recognized as critical in modulating inflammation. MRI-measured CP enlargement has been reported in neuroinflammatory disorders like MS as well as with aging and neurodegeneration. The basis of MRI-measured CP enlargement is unknown. On the basis of tissue studies demonstrating CP calcification as a common pathology associated with aging and disease, we hypothesized that previously unmeasured CP calcification contributes to MRI-measured CP volume and may be more specifically associated with neuroinflammation.

MATERIALS AND METHODS

We analyzed 60 subjects (43 healthy controls and 17 subjects with Parkinson's disease) who underwent PET/CT using 11C-PK11195, a radiotracer sensitive to the translocator protein expressed by activated microglia. Cortical inflammation was quantified as nondisplaceable binding potential. Choroid plexus calcium was measured via manual tracing on low-dose CT acquired with PET and automatically using a new CT/MRI method. Linear regression assessed the contribution of choroid plexus calcium, age, diagnosis, sex, overall volume of the choroid plexus, and ventricle volume to cortical inflammation.

RESULTS

Fully automated choroid plexus calcium quantification was accurate (intraclass correlation coefficient with manual tracing = .98). Subject age and choroid plexus calcium were the only significant predictors of neuroinflammation.

CONCLUSIONS

Choroid plexus calcification can be accurately and automatically quantified using low-dose CT and MRI. Choroid plexus calcification-but not choroid plexus volume-predicted cortical inflammation. Previously unmeasured choroid plexus calcium may explain recent reports of choroid plexus enlargement in human inflammatory and other diseases. Choroid plexus calcification may be a specific and relatively easily acquired biomarker for neuroinflammation and choroid plexus pathology in humans.

Measurement of the cosmic ray proton spectrum from 40 GeV to 100 TeV with the DAMPE satellite

The precise measurement of the spectrum of protons, the most abundant component of the cosmic radiation, is necessary to understand the source and acceleration of cosmic rays in the Milky Way. This work reports the measurement of the cosmic ray proton fluxes with kinetic energies from 40 GeV to 100 TeV, with 2 ¹/₂ years of data recorded by the DArk Matter Particle Explorer (DAMPE). This is the first time that an experiment directly measures the cosmic ray protons up to ~100 TeV with high statistics. The measured spectrum confirms the spectral hardening at ~300 GeV found by previous experiments and reveals a softening at ~13.6 TeV, with the spectral index changing from ~2.60 to ~2.85. Our result suggests the existence of a new spectral feature of cosmic rays at energies lower than the so-called knee and sheds new light on the origin of Galactic cosmic rays.

Distribution of Pathotypes of Rhynchosporium secalis and Cultivar Reaction on Barley in Alberta

Forty-four barley accessions and commercial cultivars with different levels of resistance to scald caused by Rhynchosporium secalis were evaluated for scald reaction from 1997 to 1999 at various sites in Alberta. The accessions Hudson, Atlas, Atlas 46, Atlas 68, Abyssinian, and Kitchin that have the major resistance genes were resistant to pathotypes of R. secalis at all sites. Although scald levels were low for these accessions, they were significantly different among years. Pathotypes of R. secalis and environmental conditions affected diseases levels on 32 commercial cultivars, resulting in significantly different scald reactions among sites and seasons. Resistance in commercial cultivars, AC Stacy, Kasota, and Seebe, held up at most sites with the majority of cultivars being intermediate to moderately susceptible. Cultivars that were previously considered resistant were intermediate in reaction and became increasingly susceptible at some sites from 1997 to 1999. Pathogen virulence was more diverse at the sites where the cultivars became increasingly susceptible compared with sites where the same cultivars were resistant. Scald reactions of the commercial cultivars depended on location, which reflected the presence of different pathotypes, as well as variation in environmental conditions. Consequently, scald management via cultivar choice will be dependent on location.

[Determination of chromium, manganese and nickel in six biological agents]

The determination of chromium, manganese and nickel in biological agents has obtained by flame atomic absorption spectrometry. The results show that three trace elements of body necessary are the most rich in ant factor injection liquid. The chromium content is slightly lower in the brain cell activator injection liquid, the nickel content is slightly lower in the shift factor injection liquid and the manganese is the lowest in the marrow factor injection liquid. In this paper, we have studied three trace element contents in six biological agents. It provides, useful data for clinical treatment to some trace-element-lacking diseases.

Staining paraffin embedded sections of scald of barley before paraffin removal

Staining of paraffin embedded sections with periodic acid-Schiff reagent and fast green before paraffin removal resulted in differentiation of barley seed and leaf tissue from fungal structures of Rhynchosporium secalis. Crystal violet, toluidine blue O and antiline blue also successfully stained fungal structures of R. secalis in barley leaf tissues. Staining of embedded sections before paraffin removal allows simple processing of a series of sections, saves time and reduces solvent consumption.

Liver targeting of interferon through pullulan conjugation

PURPOSE

The purpose of this study was to actively target interferon (IFN) to the liver through its chemical conjugation with pullulan, a water-soluble polysaccharide with a high affinity for the liver.

METHODS

Chemical conjugation of IFN with pullulan was achieved by a cyanuric chloride method. Following intravenous injection of the conjugates to mice, their body distribution and the activity of an IFN-induced enzyme, 2', 5'-oligoadenylate (2-5A) synthetase in the liver and other organs, were evaluated.

RESULTS

The cyanuric chloride method enabled us to prepare an IFN-pullulan conjugate that retained approximately 7-9% of the biological activity of IFN. Pullulan conjugation enhanced the liver accumulation of IFN and the retention period with the results being reproducible. When injected intravenously to mice, the IFN-pullulan conjugate enhanced the activity of 2-5A synthetase in the liver. The activity could be induced at IFN doses much lower than those of free IFN injection. In addition, the liver 2-5A synthetase induced by conjugate injection was retained for 3 days, whereas it was lost within the first day for the free IFN-injected mice.

CONCLUSIONS

IFN-pullulan conjugation was promising for IFN targeting to the liver with efficient exertion of its antiviral activity therein.