METTL3-mediated m6A modification of SOX4 regulates osteoblast proliferation and differentiation via YTHDF3 recognition.

N6-methyladenosine (m6A), the most prevalent internal modification in mRNA, is related to the pathogenesis of osteoporosis (OP). Although methyltransferase Like-3 (METTL3), an m6A transferase, has been shown to mitigate OP progression, the mechanisms of METTL3-mediated m6A modification in osteoblast function remain unclear. Here, fluid shear stress (FSS) induced osteoblast proliferation and differentiation, resulting in elevated levels of METTL3 expression and m6A modification. Through Methylated RNA Immunoprecipitation Sequencing (MeRIP-seq) and Transcriptomic RNA Sequencing (RNA-seq), SRY (Sex Determining Region Y)-box 4 (SOX4) was screened as a target of METTL3, whose m6A-modified coding sequence (CDS) regions exhibited binding affinity towards METTL3. Further functional experiments demonstrated that knockdown of METTL3 and SOX4 hampered osteogenesis, and METTL3 knockdown compromised SOX4 mRNA stability. Via RNA immunoprecipitation (RIP) assays, we further confirmed the direct interaction between METTL3 and SOX4. YTH N6-Methyladenosine RNA Binding Protein 3 (YTHDF3) was identified as the m6A reader responsible for modulating SOX4 mRNA and protein levels by affecting its degradation. Furthermore, in vivo experiments demonstrated that bone loss in an ovariectomized (OVX) mouse model was reversed through the overexpression of SOX4 mediated by adeno-associated virus serotype 2 (AAV2). In conclusion, our research demonstrates that METTL3-mediated m6A modification of SOX4 plays a crucial role in regulating osteoblast proliferation and differentiation through its recognition by YTHDF3. Our research confirms METTL3-m6A-SOX4-YTHDF3 as an essential axis and potential mechanism in OP.

Effect of carbogen on tumour oxygenation and 32P-colloid interstitial irradiation response.

BACKGROUND: Interstitial irradiation therapy using radionuclides is a slow and continual process in which the effect is exerted gradually, thus improvement of the hypoxic status of the tumor will also take a long time. It has been known that carbogen delivery of 5-15 min increases tumor oxygenation. However, the long-term effect of carbogen breathing on hypoxic cells has not yet been determined, and little is know about the effect of carbogen breathing for sensitization to interstitial irradiation therapy. MATERIAL/METHODS: 99mTc-HL91(99mTc 4,9-diaza-3,3,10,10-tetramethyldodecan-2,1-dione dioxime) hypoxic imaging was performed in 10 mice bearing sarcoma 180 (S180) before and after 2 h carbogen breathing. Radioactivity ratios of tumor to contralateral limbs (T/L) of the 2 images were calculated and compared. Mice bearing S180 were subjected to long-term carbogen breathing (2 h/day for 24 days), and were treated with or without 32P-colloid. Tumor growth rate was observed in the S180-bearing mice. RESULTS: T/L of 99mTc-HL91 uptake before and after carbogen breathing was 1.872+/-0.391 and 1.354+/-0.189, respectively (t=4.476, P<0.01). In mice in the 32P-treated air breathing group and 32P-treated carbogen breathing group, tumor growth rate did not differ on day 12 after 32P-colloid treatment, and on day 24 the tumor volume was 2.728+/-0.469 and 2.237+/-0.603 cm3 (t=2.128, P<0.05), respectively, with tumor mass being 2.437+/-0.447 and 1.965+/-0.538 g (t=2.134, P<0.05), respectively. CONCLUSIONS: Long-term carbogen breathing can increase tumor oxygenation and continual carbogen breathing is necessary for enhancing the therapeutic effect of 32P-colloid interstitial irradiation.

Evaluation of lung lesions using FDG gamma-camera PET equipped with a one-inch crystal.

The aim of this study was to evaluate the clinical value of 18-fluorodeoxyglucose (FDG) imaging with gamma-camera positron emission tomography (GCPET) equipped with a one-inch crystal for diagnosing lung lesions and determining the stage of non-small cell lung cancer (NSCLC) in regions with a high prevalence of inflammatory disease and tuberculosis. FDG-GCPET was used to examine 103 patients with suspected malignant lesions in the lung. The results of FDG-GCPET and conventional workup (CWU) including computed tomography (CT), ultrasonography and radionuclide bone scintigraphy were compared. The final diagnosis was based on the results of a histological analysis or follow-up of at least six months. The results showed 82 patients with malignant and 21 patients with benign lesions. If a lesion to background ratio > or = 2.0 was used as the threshold, then the diagnostic sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) of FDG-GCPET for NSCLC were 93.9, 57.1, 86.4, 89.5 and 70.6%, respectively. In 36 patients who underwent open-chest surgery, the diagnostic positive values of FDG-GCPET and CT for lymph-node involvement were 85% (17/20) and 65% (13/20), respectively. The diagnostic sensitivity, specificity, accuracy, PPV and NPV of FDG imaging were 85, 81.3, 83.3, 85 and 81.3%, respectively compared to the CT values of 65, 75, 69.4, 76.5 and 63.2%, respectively (NS). For the evaluation of distant metastases, 31 true-positive patients were identified during the follow-up. FDG imaging correctly identified 28 patients compared to 25 by CWU. In conclusion, FDG imaging with GCPET equipped with a one-inch crystal revealed a high lesion detection capability but a low level of clinical effectiveness for differentiating between malignant and benign lesions in the lung in regions with a high prevalence of inflammatory disease and tuberculosis. For N and M staging of NSCLC, this method may provide additional data that are not available from the CWU.

[89SrCl2 in the treatment of cancer patients with bone metastasis and pain].

OBJECTIVE: To evaluate the clinical value of (89)SrCl(2) (Ke xing Inc, Shanghai) as a palliative therapy modality for cancer patients with bone metastasis. METHODS: In 504 cancer patients with painful limitation of movement due to bony metastasis, a dose of 1.48-2.22 MBq/kg (40-60 uCi/kg) iv infusion of (89)SrCl(2) was given. RESULTS: In 97 patients (19.2%) there was no improvement in pain and life quality, 298 patients (59.1%) showed mild to moderate improvement (moderately effective), 109 patients (21.6%) became free of pain and were subsequently fully ambulatory (markedly effective). The pain relief appeared from D1-D46 after (89)SrCl(2) administration, most frequently from D5-D14. The palliative effect could last for about 56 days to 13 months. Repeated bone scans of some patients showed that the metastatic foci in the bone became smaller or even disappeared gradually after the administration of (89)SrCl(2). Approximately 55% of patients experienced grade I approximately III bone marrow depression attributable to (89)SrCl(2), which would return to the pre-treatment level within 3 approximately 9 months. CONCLUSION: (89)SrCl(2) is effective and safe for the relief of bone pain and improvement of quality of life in cancer patients with painful bony metastasis.

In vitro and in vivo evaluation of a novel capsule for colon-specific drug delivery.

The aim of this study was to estimate colon-specific drug delivery of a novel capsule (CS capsule). Theophylline was used as model drug and little was released from the CS capsules in the release medium mimicking physiological environment of stomach to small intestine. However, 66.7 +/- 8.8% theophylline was released from the capsules in the phosphate buffer (pH 6.8) mimicking the physiological environment of colon in the next 4 h, while the addition of galactomannanase (39.3 U/L) accelerated the disintegration of the CS capsule and enhanced the release rate to 92.6 +/- 6.0%. Rats in vivo pharmacokinetics demonstrated that the relative bioavailability of theophylline after intragastric administration of CS capsules was 76.72% with delayed T(max) of 8 h comparing to that of theophylline solution with T(max) of 1.5 h. Radiolabeled with technetium-99m, the CS capsule could keep intact from stomach to small intestine while disintegration of the CS capsule was observed in the proximal colon or the joint between the distal small intestine and right colon. A great quantity of radiolabeled marker was released as well as distributed in the whole colon at 10 h after administration. As a whole, the CS capsule prepared could provide an alternative carrier for the colon-specific drug delivery.

Application of FDG-PET for detection of malignant lesions in patients with elevated blood tumor markers but without a history of malignancy.

The aim of this study was to evaluate the clinical application of 18-fluorodeoxyglucose positron emission tomography (FDG-PET) imaging for the detection of malignant lesions. A total of 132 patients with increased levels of blood tumor markers but without a prior history of malignancy were examined. The results of FDG-PET and conventional work-up (CWU) including computed tomography (CT), ultrasonography, radionuclide bone scintigraphy and endoscopy were compared. The final diagnosis was based on pathological evidence, other medical imaging results and a follow-up of at least 6 months. There were 61 patients with malignant lesions and 71 without (benign lesions, n=35; healthy individuals, n=36). The average number of elevated tumor markers and the average increase in these tumor markers were greater in the malignant group than in the non-malignant group. FDG-PET imaging revealed that the maximum standardized uptake value (SUVmax) of the major lesion in patients with malignant (n=61) and benign (n=35) tumors was not significantly related to increased levels of tumor markers (r=0.10, p<0.05). In patients with malignant lesions and an SUVmax ≥3.0, the diagnostic sensitivity, specificity, accuracy, positive predictive value and negative predictive value of FDG-PET were 95.1, 83.1, 88.6, 82.9 and 95.2%, respectively. CWU identified 61 (100%) true-positive patients. No statistically significant differences in sensitivity were observed between the results of FDG-PET and CWU (p>0.05). In 36 healthy subjects without abnormal CWU findings, no abnormal FDG accumulation was revealed by FDG-PET imaging. In conclusion, FDG-PET imaging is a valuable tool for the detection of malignant lesions in patients with increased levels of blood tumor markers but without a history of malignancy. It is therefore reasonable to apply FDG-PET imaging in situations in which the results of CWU are inconclusive, or when patients wish to limit the number of examinations they must undergo.