Background N6-methyladenosine (m6A) modification is the most pervasive modification in mRNA, and has been considered as a new layer of epigenetic regulation on mRNA processing, stability and translation. Despite its functional significance in various physiological processes, the role of the m6A modification involved in breast cancer is yet fully understood. Methods We used the m6A-RNA immunoprecipitation sequencing to identify the potential targets in breast cancer. To determine the underlying mechanism for the axis of FTO-BNIP3, we performed a series of in vitro and in vivo assays in 3 breast cancer cell lines and 36 primary breast tumor tissues and 12 adjunct tissues. Results We showed that FTO, a key m6A demethylase, was up-regulated in human breast cancer. High level of FTO was significantly associated with lower survival rates in patients with breast cancer. FTO promoted breast cancer cell proliferation, colony formation and metastasis in vitro and in vivo. We identified BNIP3, a pro-apoptosis gene, as a downstream target of FTO-mediated m6A modification. Epigenetically, FTO mediated m6A demethylation in the 3’UTR of BNIP3 mRNA and induced its degradation via an YTHDF2 independent mechanism. BNIP3 acts as a tumor suppressor and is negatively correlated with FTO expression in clinical breast cancer patients. BNIP3 dramatically alleviated FTO-dependent tumor growth retardation and metastasis. Conclusions Our findings demonstrate the functional significance of the m6A modification in breast cancer, and suggest that FTO may serve as a novel potential therapeutic target for breast cancer. Electronic supplementary material The online version of this article (10.1186/s12943-019-1004-4) contains supplementary material, which is available to authorized users.

Success in treating hepatitis B virus (HBV) infection with nucleoside analog drugs like lamivudine is limited

To determine whether adefovir is active against lamivudine-resistant hepatitis B virus (HBV), the inhibition constants of adefovir diphosphate and lamivudine triphosphate for wild-type and mutant human HBV DNA polymerases, which contain amino acid substitutions associated with lamivudine resistance, were compared. Recombinant wildtype and mutant human HBV DNA polymerases were expressed and substantially purified using a baculovirus expression system and immunoaffinity chromatography. HBV DNA polymerase mutants M552I, M552V, and L528M/ M552V showed resistance to lamivudine triphosphate with inhibition constants (K i ) increased by 8.0-fold, 19.6-fold, and 25.2-fold compared with that of wild-type HBV DNA polymerase. However, these mutants remained sensitive to adefovir diphosphate with the inhibition constants increasing by 1.3-fold and 2.2-fold or decreasing by 0.79-fold. The L528M single mutation, identified in patients with increasing HBV DNA levels during therapy with famciclovir, also remained sensitive to adefovir diphosphate with the inhibition constant increased by only 2.3-fold. (HEPATOLOGY 1998;28:1669-1673.)Chronic hepatitis B virus (HBV) infection is a major health problem because more than 350 million people are infected worldwide. HBV is a major cause of chronic hepatitis, cirrhosis, and hepatocellular carcinoma, and it ranks as the ninth most common cause of death worldwide. 1 Current treatment regimens rely primarily on interferon alfa therapy; however interferon alfa has been successful in only approximately one third of patients, is limited to patients with compensated liver disease, and is associated with a variety of side effects. Fortunately, there are several new anti-HBV agents (such as lamivudine, 2-6 famciclovir, 7 adefovir dipivoxil, 8,9 lobucavir, 10 and BMS-200475 11 ) currently being evaluated in clinical trials.Adefovir is an acyclic nucleotide monophosphate analogue with broad-spectrum antiviral activity against retroviruses, hepadnaviruses, and herpesviruses. 12-15 Adefovir dipivoxil (the oral prodrug of adefovir) is being used in clinical trials for the treatment of HBV 8 and human immunodeficiency virus (HIV) infections. In a recent phase II clinical study, 15 patients with chronic HBV who were treated with 30 mg adefovir dipivoxil daily for 12 weeks had a median 4.1 log reduction in serum HBV DNA by polymerase chain reaction (PCR) assay. 9 Lamivudine is a potent inhibitor of HIV replication and has been approved for the treatment of HIV infection in combination with zidovudine. Lamivudine is also effective against HBV and is in the late stage of development for the treatment of HBV infection. [2][3][4][5][6] Resistance to lamivudine has been observed in both immunocompetent 16 patients and patients who have undergone orthotopic liver transplantation [17][18][19][20] infected with HBV. Most recently, genotypic resistance was observed in 14% of 267 Asian patients treated with lamivudine for 12 months. 4 The resistance is associated with mutations of methionine 552 to either isoleu...

G proteins are key mediators of G protein-coupled receptor signalling, which facilitates a plethora of important physiological processes. The cyclic depsipeptides YM-254890 and FR900359 are the only known specific inhibitors of the Gq subfamily of G proteins; however, no synthetic route has been reported previously for these complex natural products and they are not easily isolated from natural sources. Here we report the first total synthesis of YM-254890 and FR900359, as well as of two known analogues, YM-385780 and YM-385781. The versatility of the synthetic approach also enabled the design and synthesis of ten analogues, which provided the first structure–activity relationship study for this class of compounds. Pharmacological characterization of all the compounds at Gq-, Gi- and Gs-mediated signalling provided succinct information on the structural requirements for inhibition, and demonstrated that both YM-254890 and FR900359 are highly potent inhibitors of Gq signalling, with FR900359 being the most potent. These natural products and their analogues represent unique tools for explorative studies of G protein inhibition.

In December 2019, an outbreak of coronavirus disease 2019 (COVID‐19) emerged in Wuhan, China. Although it has been reported that some COVID‐19 patients showed elevated liver biochemistries, there are few studies regarding clinical features and prognosis of these patients. In this multicenter, retrospective study, we collected data on laboratory‐confirmed COVID‐19 patients from three hospitals in Wuhan, China, who died or were discharged between February 1, 2020, and February 20, 2020. The data on demographics, comorbidities, clinical symptoms, laboratory examinations on admission, complications, treatment, and outcome were collected. A total of 482 patients were enrolled in this study. Of those, 142 (29.5%) patients showed abnormal liver biochemistries on admission, and patients with elevated alanine aminotransferase (ALT), aspartate aminotransferase (AST), and total bilirubin (TBIL) accounted for 67.6%, 69.0%, and 16.2%, respectively. Those with abnormal liver biochemistries showed higher percentages of severe cases and comorbidities and were more likely to have dyspnea, chest distress or pain, and increased hemoglobin (Hb) on admission. Higher rates of complications and mortality and worse recovery when discharged were observed in patients with abnormal AST or TBIL. The multivariable regression analysis showed that chest distress or pain (odds ratio [OR], 1.765; P = 0.018), dyspnea (OR, 2.495; P = 0.001), elevated C‐reactive protein [CRP] level (OR, 1.007; P = 0.008), elevated white blood count (WBC) (OR, 1.139; P = 0.013), and elevated Hb concentration (OR, 1.024; P = 0.001) were independent factors associated with elevated liver biochemistries in COVID‐19 patients. Conclusion: Elevated liver biochemistries were common in COVID‐19 patients. Patients with hypoxia or severe inflammation are more likely to experience increased liver biochemistries on admission. Those with abnormal AST or TBIL on admission are more likely to suffer from severe complications and death.

Take home message: The median time from symptoms onset to viral RNA shedding was 19 days. Patients with CHD comorbidity or decreased albumin levels experienced delays in clearance of SARS-CoV-2 RNA.

Cidofovir (CDV) (HPMPC) has potent in vitro and in vivo activity against human cytomegalovirus (HCMV), CDV diphosphate (CDVpp), the putative antiviral metabolite of CDV, is an inhibitor and an alternate substrate of HCMV DNA polymerase. CDV is incorporated with the correct complementation to dGMP in the template, and the incorporated CDV at the primer end is not excised by the 3'-to-5' exonuclease activity of HCMV DNA polymerase. The incorporation of a CDV molecule causes a decrease in the rate of DNA elongation for the addition of the second natural nucleotide from the singly incorporated CDV molecule. The reduction in the rate of DNA (36-mer) synthesis from an 18-mer by one incorporated CDV is 31% that of the control. However, the fidelity of HCMV DNA polymerase is maintained for the addition of the nucleotides following a single incorporated CDV molecule. The rate of DNA synthesis by HCMV DNA polymerase is drastically decreased after the incorporation of two consecutive CDV molecules; the incorporation of a third consecutive CDV molecule is not detectable. Incorporation of two CDV molecules separated by either one or two deoxynucleoside monophosphates (dAMP, dGMP, or dTMP) also drastically decreases the rate of DNA chain elongation by HCMV DNA polymerase. The rate of DNA synthesis decreases by 90% when a template which contains one internally incorporated CDV molecule is used. The inhibition by CDVpp of DNA synthesis by HCMV DNA polymerase and the inability of HCMV DNA polymerase to excise incorporated CDV from DNA may account for the potent and long-lasting anti-CMV activity of CDV.

BackgroundVitamin D is involved in the host immune response toward Mycobacterium tuberculosis. However, the efficacy of vitamin D supplementation on sputum conversion, clinical response to treatment, adverse events, and mortality in patients with pulmonary tuberculosis (PTB) remains controversial. We aimed to clarify the efficacy and safety of vitamin D supplementation in PTB treatment.MethodsWe searched Medline, Embase, Cochrane Central Register of Controlled Trials, Web of Science for double-blind, randomized controlled trials of vitamin D supplementation in patients with PTB that reported sputum conversion, clinical response to treatment, adverse events, or mortality, published from database inception to November 26, 2017. This study was registered with PROSPERO, number CRD42018081236.ResultsA total of 1787 patients with active PTB receiving vitamin D supplementation along with standard anti-tuberculosis regimen were included in the eight trials with different doses of vitamin D ranging from 1000 IU/day to 600,000 IU/month at different intervals. Primary analysis revealed that vitamin D supplementation increased the proportion of sputum smear and culture conversions (OR 1.21, 95%CI 1.05~ 1.39, z = 2.69, P = 0.007; OR 1.22, 95%CI 1.04~ 1.43, z = 2.41, P = 0.02), but did not improve the time to sputum smear and culture conversions (HR 1.07, 95%CI 0.83~ 1.37, z = 0.50, P = 0.62; HR 0.97, 95%CI 0.76~ 1.23, z = 0.29, P = 0.77). In the secondary analysis, vitamin D improved serum 25(OH)D, plasma calcium concentration, lymphocyte count, and chest radiograph (MD 103.36, 95%CI 84.20~ 122.53, z = 10.57, P < 0.00001; SMD 0.26, 95%CI 0.15~ 0.37, z = 4.61, P < 0.00001; MD 0.09, 95%CI 0.03~ 0.14, z = 2.94, P = 0.003); MD -0.33, 95% CI -0.57~ − 0.08 z = 2.57, P = 0.01), but had no impact on adverse events, mortality and other indicators(TB score, BMI, mean mid-upper arm circumference, weight gain, CRP, ESR, and other blood cells) (P > 0.05).ConclusionsVitamin D supplementation can be considered as a combination therapy in patients with PTB.Electronic supplementary materialThe online version of this article (10.1186/s12890-018-0677-6) contains supplementary material, which is available to authorized users.