p21 Regulates Wnt-Notch balance via DREAM/MMB/Rb-E2F1 and maintains intestinal stem cell homeostasis.

The crosstalk and balance regulation of Wnt-Notch have been known to be essential for cell fate decision and tissue regeneration, however, how this balance is maintained and how the Wnt-Notch pathways are connected with cell cycle regulation is still not clear. By analyzing the molecular alterations in mouse model with accelerated aging phenotypes due to loss of p21 function in a Werner syndrome background, we observed that Wnt3 and ß-Catenin were down-regulated, while Notch1 and Hes1 were up-regulated. This disruption in Wnt-Notch signaling was accompanied by the loss of intestinal stem cell compartment, increase in Bmi1 positive cells, loss of Olfm4/Lgr5 positive cells, and reduced secretory Paneth cells and goblet cells in the intestinal crypts of p21TKO mice. BrdU incorporation, cleaved caspase 3, and Tunel assay results revealed the fast turnover of intestinal epithelia, which may result in abnormal stem cell mobilization and exhaustion of the stem cell reservoir in the intestinal crypts. We further identified shift of DREAM complex towards MMB complex due to the loss of p21 as the cause for faster turnover of intestinal epithelia. Importantly, we identified the E2F1 as the transcriptional regulator for Notch1, which linked the p21-DREAM/MMB/Rb-E2F1 pathway with Wnt-Notch pathway. The overexpression of p21 rescued the DREAM pathway, as well as the imbalance of Wnt-Notch pathway. In summary, our data identify p21 as an important factor in maintaining sequential mobilization, proliferation, and homeostasis of intestinal stem cells.

Macrophage-engaging peptidic bispecific antibodies (pBsAbs) for immunotherapy via a facile bioconjugation strategy.

Bispecific antibodies are artificial molecules that fuse two different antigen-binding sites of monoclonal antibodies into one single entity. They have emerged as a promising next-generation anticancer treatment. Despite the fascinating applications of bispecific antibodies, the design and production of bispecific antibodies remain tedious and challenging, leading to a long R&D process and high production costs. We herein report an unprecedented strategy to cyclise and conjugate tumour-targeting peptides on the surface of a monoclonal antibody to form a novel type of bispecific antibody, namely the peptidic bispecific antibody (pBsAb). Such design combines the merits of highly specific monoclonal antibodies and serum-stable cyclic peptides that endows an additional tumour-targeting ability to the monoclonal antibody for binding with two different antigens. Our results show that the novel pBsAb, which comprises EGFR-binding cyclic peptides and an anti-SIRP-α monoclonal antibody, could serve as a macrophage-engaging bispecific antibody to initiate enhanced macrophage-cancer cell interaction and block the "don't eat me" signal between CD47-SIRP-α, as well as promoting antibody-dependent cellular phagocytosis and 3D cell spheroid infiltration. These findings give rise to a new type of bispecific antibody and a new platform for the rapid generation of new bispecific antibodies for research and potential therapeutic uses.

Chemical Modification of Cytochrome C for Acid-Responsive Intracellular Apoptotic Protein Delivery for Cancer Eradication.

Delivering bioactive proteins into cells without carriers presents significant challenges in biomedical applications due to limited cell membrane permeability and the need for targeted delivery. Here, we introduce a novel carrier-free method that addresses these challenges by chemically modifying proteins with an acid-responsive cell-penetrating peptide (CPP) for selective intracellular delivery within tumours. Cytochrome C, a protein known for inducing apoptosis, served as a model for intracellular delivery of therapeutic proteins for cancer treatment. The CPP was protected with 2,3-dimethyl maleic anhydride (DMA) and chemically conjugated onto the protein surface, creating an acid-responsive protein delivery system. In the acidic tumour microenvironment, DMA deprotects and exposes the positively charged CPP, enabling membrane penetration. Both in vitro and in vivo assays validated the pH-dependent shielding mechanism, demonstrating the modified cytochrome C could induce apoptosis in cancer cells in a pH-selective manner. These findings provide a promising new approach for carrier-free and tumour-targeted intracellular delivery of therapeutic proteins for a wide range of potential applications.

Profiles and persistence of initial antiretroviral therapy among HIV infected patients in taiwan: A nationwide population-based cross-sectional study from 2011 to 2017.

BACKGROUND/PURPOSE: Antiretroviral therapy (ART) has been applied for treating patients with human immunodeficiency virus (HIV) for decades. Our study explored initial ART use patterns and ART persistence in patients who begin HIV treatment in Taiwan. METHODS: The National Health Insurance Research Database in Taiwan was used in our study. The study cohort included patients who are incident ART users from 2011 to 2017. The patterns of ART-based regimens initiated were documented, mainly including non-nucleoside reverse transcriptase inhibitor (NNRTI)-based, protease inhibitor (PI)-based and integrase inhibitor (INI)-based regimens. Time from HIV diagnosis to ART initiation, ART persistence, and ART treatment patterns were documented. RESULTS: There were 19,726 incident ART users. While NNRTI-based regimen was the first choice of initial ART from 2011 to 2017, INI-based regimen accounted for 52.9% of total ART initiation and was the most commonly prescribed regimen in 2017. PI-based regimen decreased from 17.0% to 0.7% during the study period. We found that changes of initial ART between 2011 and 2017 were common, consist with the changes of National Imbursement Guideline for HIV therapy in Taiwan. CONCLUSIONS: We found a trend of rapidly increasing INI-based regimen and decreasing PI-based regimen during the study period. Shorten time window for initiating ART was found according to reimbursement regulation of STR as the first-line therapy and government policy of same-day HIV testing and treatment initiation. The persistence of ART was influenced by treatment guideline during the study period.

Potential or contraindicated drug-drug interactions with antiretroviral therapy in real-world settings in Taiwan.

BACKGROUND/PURPOSE: Given the complex metabolic pathway of antiretroviral therapy (ART), polypharmacy may increase the risk of drug-drug interactions (DDIs). Therefore, we investigated the frequency of DDIs during ART exposure to improve medical care for patients with human immunodeficiency virus (HIV). METHODS: This was a nationwide cross-sectional study using claims data from the National Health Insurance in Taiwan in 2016. Potential or contraindicated DDIs with recommended first-line ART (1L-ART) or protease inhibitors (PIs) were identified from the University of Liverpool drug interaction database. Fisher's exact or chi-square test was used to determine the significance of categorical variables. RESULTS: A total of 25,863 HIV-infected individuals were identified. Regarding 1L-ART users, patients with contraindicated DDIs accounted for 1-4%, whereas those with potential DDIs accounted for 15-50%. The most frequently coprescribed medications related to potential DDIs were diclofenac and polyvalent cation-containing antacids. Among PI users, 8-10% of them had contraindicated DDIs while 44-50% of them had potential DDIs. The medications related to potential DDIs with PIs were zolpidem, betamethasone, polyvalent cation-containing antacids, and loperamide. CONCLUSION: Our study showed a low prevalence of contraindicated DDIs in the HIV population; however, more attention should be paid to a high proportion of potential DDIs. Strategies to avoid these DDIs should be implemented if possible. Further research that focuses on the long-term clinical impact of potential DDIs is warranted.

Comparison of risk of acute kidney injury between patients receiving the combination of teicoplanin and piperacillin/tazobactam versus vancomycin and piperacillin/tazobactam.

BACKGROUND/PURPOSE: To compare the risk of acute kidney injury (AKI) among patients receiving teicoplanin (TA) plus piperacillin/tazobactam (TZP) versus vancomycin (VAN) plus TZP. METHODS: This was a retrospective cohort study using electronic health records. Patients were included if a combination of glycopeptide and TZP or other selected ß-lactams were used during hospitalization. In the main analysis, two study groups were identified: TA + TZP and VAN + TZP. We used 1:1 propensity score matching to control for potential confounders, and hazard ratio (HR) of AKI between study groups was calculated. We further compared the risk of AKI between patients receiving VAN + TZP and VAN + ß-lactams as an auxiliary analysis to verify the validity of the study design. RESULTS: The final sample contained 211 pairs of patients receiving either TA + TZP or VAN + TZP. The median dosage of TA and VAN were 10.3 and 26.7 mg/kg/day, respectively. The median trough level of VAN was 12.3 mg/L. The AKI risk in the TA + TZP group was similar to that in the VAN + TZP group (12.3% vs. 11.4%; HR = 1.25 [0.72-2.18], p = 0.44). The auxiliary analysis showed a higher risk of AKI in the VAN + TZP group than in the VAN + ß-lactam group (13.2% vs. 9.6%; HR = 1.63 [1.04-2.55], p = 0.03). CONCLUSION: Our study results showed that the risk of AKI were similar for patients receiving TA + TZP and VAN + TZP. However, low VAN and high TA dose may play a role in this finding. Further investigation on the association between AKI and TA + TZP is required.

One-pot peptide cyclisation and surface modification of photosensitiser-loaded red blood cells for targeted photodynamic therapy.

We report herein a one-pot approach to cyclise a tumour-targeting peptide and conjugate it on the surface of red blood cells loaded with a boron dipyrromethene-based photosensitiser using a bifunctional linker consisting of a bis(bromomethyl)phenyl unit and an ortho-phthalaldehyde unit. This cell-based photosensitiser with surface modification with cyclic RGD peptide moieties can selectively bind against the αvß3 integrin-overexpressed cancer cells, leading to enhanced photocytotoxicity. The results demonstrate that this facile strategy is effective for live-cell surface modification for a wide range of applications.

The Distinct Function of p21Waf1/Cip1 With p16Ink4a in Modulating Aging Phenotypes of Werner Syndrome by Affecting Tissue Homeostasis.

Human Werner syndrome (WS) is an autosomal recessive progeria disease. A mouse model of WS manifests the disease through telomere dysfunction-induced aging phenotypes, which might result from cell cycle control and cellular senescence. Both p21Waf1/Cip1 (p21, encoded by the Cdkn1a gene) and p16Ink4a (p16, encoded by the Ink4a gene) are cell cycle inhibitors and are involved in regulating two key pathways of cellular senescence. To test the effect of p21 and p16 deficiencies in WS, we crossed WS mice (DKO) with p21 -/- or p16 -/- mice to construct triple knockout (p21-TKO or p16-TKO) mice. By studying the survival curve, bone density, regenerative tissue (testis), and stem cell capacity (intestine), we surprisingly found that p21-TKO mice displayed accelerated premature aging compared with DKO mice, while p16-TKO mice showed attenuation of the aging phenotypes. The incidence of apoptosis and cellular senescence were upregulated in p21-TKO mice tissue and downregulated in p16-TKO mice. Surprisingly, cellular proliferation in p21-TKO mice tissue was also upregulated, and the p21-TKO mice did not show telomere shortening compared with age-matched DKO mice, although p16-TKO mice displayed obvious enhancement of telomere lengthening. Consistent with these phenotypes, the SIRT1-PGC1 pathway was upregulated in p16-TKO but downregulated in p21-TKO compared with DKO mouse embryo fibroblasts (MEFs). However, the DNA damage response pathway was highly activated in p21-TKO, but rescued in p16-TKO, compared with DKO MEFs. These data suggest that p21 protected the stem cell reservoir by regulating cellular proliferation and turnover at a proper rate and that p21 loss in WS activated fairly severe DNA damage responses (DDR), which might cause an abnormal increase in tissue homeostasis. On the other hand, p16 promoted cellular senescence by inhibiting cellular proliferation, and p16 deficiency released this barrier signal without causing severe DDR.

Nephrotoxicity of teicoplanin-based combination therapy: focus on piperacillin/tazobactam and other anti-pseudomonal ß-lactams.

BACKGROUND: The concurrent use of vancomycin and piperacillin/tazobactam increases the risk of acute kidney injury (AKI) compared with vancomycin use with other anti-pseudomonal ß-lactams (OAPBs). Teicoplanin is a glycopeptide antibiotic with lower nephrotoxicity than that of vancomycin. Whether the concomitant use of teicoplanin and piperacillin/tazobactam also increases the risk of AKI remains unknown. OBJECTIVES: To evaluate the AKI risk between teicoplanin-piperacillin/tazobactam and teicoplanin-OAPBs. METHODS: This was a retrospective, propensity score-matched cohort study. Adult patients receiving teicoplanin-based combination therapy were included. OAPBs included cefepime, cefoperazone/sulbactam, ceftazidime, doripenem, imipenem/cilastatin and meropenem. Propensity score matching was performed to balance demographic and confounding factors. The primary endpoint was AKI during combination therapy. RESULTS: After propensity score matching, 954 patients (teicoplanin-piperacillin/tazobactam: teicoplanin-OAPBs, 1:3 matched, 243 pairs in total) were included for analysis. The mean age was 66.3 years in the matched cohort and 17.1% of patients had shock. Use of nephrotoxic medications (45.7% versus 48.7%) and baseline renal function (78.88 ± 31.26 versus 81.05 ± 31.53 mL/min/1.73 m2) were similar in the two groups. The median teicoplanin dose was 10.7 mg/kg in both groups. The groups did not differ significantly in terms of AKI risk (14.8% versus 14.2%, P = 0.815). However, the time to AKI appeared shorter in the teicoplanin-piperacillin/tazobactam group (4.64 ± 2.33 versus 6.29 ± 4.72 days, P = 0.039). CONCLUSIONS: The combination of teicoplanin and piperacillin/tazobactam was not associated with an increased risk of AKI compared with teicoplanin and OAPBs.

Mouse models in modeling aging and cancer.

Mouse models have been widely used in the research of human diseases. Aging, just as cancer, is influenced by the interaction of various genetic and environmental factors. Currently, aging could be induced by many mechanism, including telomere dysfunction, oxidase stress, DNA damage and epigenetic changes. Many of these genetic pathways are also shared by aging and cancer. The mouse models generated to study these pathways might manifest either aging or cancer phenotypes, sometimes both, which in deed has worked as a good model system in understanding the correlation between aging and cancer. Here, we reviewed these mouse models that were generated to model aging or cancer. These mouse models might help us put those related pathways in context and discover essential interactions in cancer and aging regulation.

Safety of high-dose daptomycin in patients with severe renal impairment.

BACKGROUND: Treatment options are limited for infections due to multidrug-resistant Gram-positive pathogens. Daptomycin is a lipopeptide antibiotic with concentration-dependent killing characteristic and dose-dependent post-antibiotic effect. To achieve optimized pharma-codynamic effect, some experts advocated using a high dose of daptomycin (≥9 mg/kg) for severe infections. However, the safety of high-dose therapy in patients with renal impairment remains unknown. This study was aimed to evaluate the safety of daptomycin in patients with severe renal impairment. METHODS: This was a retrospective study performed by reviewing electronic medical records. Patients with severe renal impairment who were treated with daptomycin in a tertiary teaching hospital between January 1, 2013, and June 30, 2016, were included for evaluation. The incidence rates of creatine kinase (CK) elevation between high-dose (≥9 mg/kg) and standard-dose (<9 mg/kg) groups were compared. RESULTS: Overall, 164 patients met the inclusion criteria, and 114 (69.5%) of them were on renal replacement therapy. Vancomycin-resistant enterococci were the most common pathogens (61.3%) of the patients with documented pathogens. The treatment success rate was 51.6% in the 91 patients with bacteremia. The average dose of daptomycin was 8.0±2.3 mg/kg, and 37 (22.6%) patients received ≥9 mg/kg. CK levels were followed in 108 (65.9%) patients. Significantly higher incidence of CK elevation was found in the high-dose group compared with that in the standard-dose group (10.8% vs 1.6%, P<0.05). Moreover, patients with elevated CK received a higher dose of daptomycin than those without (9.3±1.2 vs 7.9±2.3 mg/kg, P<0.05). There was no significant difference in the rate of CK elevation between patients treated with different dosing frequency or with the concurrent use of statins, fibrate, or colchicine. CONCLUSIONS: In patients with severe renal impairment, high-dose (≥9 mg/kg) daptomycin therapy may result in a significantly higher incidence of CK elevation. More frequent CK monitoring is warranted to avoid potential harm in this population.

Loss of p21 promoted tumorigenesis in the background of telomere dysfunctions induced by TRF2 and Wrn deficiency.

Werner syndrome (WS) is a rare autosomal recessive progeria disease with genetic instability/cancer predisposition, thus a good model in understanding aging related carcinogenesis. Telomere dysfunction induced cellular senescence is essential in the manifestation of the WS phenotype. Our previous data has shown that p21 (encoded by Cdkn1a gene) could induce cellular senescence and suppress cellular growth of ALT (alternative lengthening of telomere) tumors derived from WS, suggested that p21 might play a key role in maintaining senescence of WS cells. To confirm the role of p21 in suppressing telomere dysfunction induced tumorigenesis, we overexpressed dominant negative protein TRF2ΔBΔM in p21-/- mouse embryonic fibroblasts (MEFs). To further stress the cell, we crossed Wrn-/- mice with p21-/- mice to obtained p21-/-Wrn-/- MEFs, and overexpressed TRF2ΔBΔM in these MEFs to induce telomere dysfunction similar to that in WS cells. Our data showed that, in the context of p21-/- TRF2ΔBΔM, loss of p21 function rescued cellular senescence, and induced p53 mutation, but did not induce tumorigenesis. However, in the set of p21-/-Wrn-/- TRF2ΔBΔM, loss of p21 function induced p53 mutation and tumorigenesis. To further verify the role of p21 in suppressing telomere dysfunction related tumorigenesis, we knocked down p21 in non-tumorigenic immortalized cells derived from WS MEFs (mTerc -/-Wrn-/- ), and found that loss of p21 could induce ALT tumorigenesis, which displayed typical smear pattern of telomere length and arc-shaped telomeric DNA. In another hand, recovering telomerase activity in these MEFs could also induce tumorigenesis without affecting p21 expression level. Together our data suggested that p21 controlled cell cycle regulation played an essential role in suppressing telomere dysfunction-related tumorigenesis. These data also suggested that the genetic context is essential in determining the role of p21 in cancer prevention. Therefore, targeting p21 in the treatment of human degenerative diseases would require a personalized genetic background screen.

The relationship between RASSF1A gene promoter methylation and the susceptibility and prognosis of melanoma: A meta-analysis and bioinformatics.

BACKGROUND: The function of the tumor suppressor gene RASSF1A in cancer cells has been detailed in many studies. However, due to the methylation of its promoter, the expression of RASSF1A is missing in most cancers. In the literature, we found that the conclusion regarding the relationship between RASSF1A gene promoter methylation and the susceptibility and prognosis of melanoma was not unified. This study adopts the use of a meta-analysis and bioinformatics to explore the relationship between RASSF1A gene promoter methylation and the susceptibility and prognosis of melanoma. METHODS: Data on melanoma susceptibility were downloaded from the PubMed, Cochrane Library, Web of Science and Google Scholar databases, which were analyzed via a meta-analysis. The effect sizes were estimated by measuring an odds ratio (OR) with a 95% confidence interval (CI). We also used a chi-squared-based Q test to examine the between-study heterogeneity, and used funnel plots to evaluate publication bias. The data on melanoma prognosis, which were analyzed by bioinformatics methods, were downloaded from The Cancer Genome Atlas (TCGA) project. The effect sizes were estimated by measuring the hazard ratios (HRs) with a 95% confidence interval (CI). RESULTS: Our meta-analysis included 10 articles. We found that RASSF1A gene promoter methylation was closely related to melanoma susceptibility (OR = 12.67, 95% CI: 6.16 ∼ 26.05, z = 6.90, P<0.0001 according to a fixed effects model and OR = 9.25, 95% CI: 4.37 ∼ 19.54, z = 5.82, P<0.0001 according to a random effects model). The results of the meta-analysis did not reveal any heterogeneity (tau2 = 0.00; H = 1 [1; 1.55]; I2 = 0% [0%; 58.6%], P = 0.5158) or publication bias (t = 0.87, P = 0.4073 by Egger's test; Z = 0.45, P = 0.6547 by Begg's test); therefore, we believe that the results of our meta-analysis were more reliable. To explore the relationship between RASSF1A gene methylation, the prognosis of melanoma and the clinical features of this cancer type, we used the melanoma DNA methylation data and clinical data from TCGA project. We found that RASSF1A gene promoter methylation and melanoma prognosis did not demonstrate any relationship (HR was 0.94 (95% CI = [0.69; 1.27], P = 0.694) with disease-free survival and 0.74 (95% CI = [0.53; 1.05], P = 0.106) for overall survival), and no significant difference was observed between RASSF1A gene promoter methylation and the clinical-pathological features of melanoma. CONCLUSIONS: In conclusion, the meta-analysis of the data in these articles provides strong evidence that the methylation status of the RASSF1A gene promoter was strongly related to melanoma susceptibility. Our bioinformatics analysis revealed no significant difference between RASSF1A gene promoter methylation and the prognosis and clinical-pathological features of melanoma.