Brain network centrality and connectivity are associated with clinical subtypes and disease progression in Parkinson's disease.

To investigate brain network centrality and connectivity alterations in different Parkinson's disease (PD) clinical subtypes using resting-state functional magnetic resonance imaging (RS-fMRI), and to explore the correlation between baseline connectivity changes and the clinical progression. Ninety-two PD patients were enrolled at baseline, alongside 38 age- and sex-matched healthy controls. Of these, 85 PD patients underwent longitudinal assessments with a mean of 2.75 ± 0.59 years. Two-step cluster analysis integrating comprehensive motor and non-motor manifestations was performed to define PD subtypes. Degree centrality (DC) and secondary seed-based functional connectivity (FC) were applied to identify brain network centrality and connectivity changes among groups. Regression analysis was used to explore the correlation between baseline connectivity changes and clinical progression. Cluster analysis identified two main PD subtypes: mild PD and moderate PD. Two different subtypes within the mild PD were further identified: mild motor-predominant PD and mild-diffuse PD. Accordingly, the disrupted DC and seed-based FC in the left inferior frontal orbital gyrus and left superior occipital gyrus were severe in moderate PD. The DC and seed-based FC alterations in the right gyrus rectus and right postcentral gyrus were more severe in mild-diffuse PD than in mild motor-predominant PD. Moreover, disrupted DC were associated with clinical manifestations at baseline in patients with PD and predicted motor aspects progression over time. Our study suggested that brain network centrality and connectivity changes were different among PD subtypes. RS-fMRI holds promise to provide an objective assessment of subtype-related connectivity changes and predict disease progression in PD.

Extracellular-vesicle-packaged S100A11 from osteosarcoma cells mediates lung premetastatic niche formation by recruiting gMDSCs.

The premetastatic niche (PMN) contributes to lung-specific metastatic tropism in osteosarcoma. However, the crosstalk between primary tumor cells and lung stromal cells is not clearly defined. Here, we dissect the composition of immune cells in the lung PMN and identify granulocytic myeloid-derived suppressor cell (gMDSC) infiltration as positively associated with immunosuppressive PMN formation and tumor cell colonization. Osteosarcoma-cell-derived extracellular vesicles (EVs) activate lung interstitial macrophages to initiate the influx of gMDSCs via secretion of the chemokine CXCL2. Proteomic profiling of EVs reveals that EV-packaged S100A11 stimulates the Janus kinase 2/signal transducer and activator of transcription 3 signaling pathway in macrophages by interacting with USP9X. High level of S100A11 expression or circulating gMDSCs correlates with the presentation of lung metastasis and poor prognosis in osteosarcoma patients. In summary, we identify a key role of tumor-derived EVs in lung PMN formation, providing potential strategies for monitoring or preventing lung metastasis in osteosarcoma.

Abnormal cerebellum connectivity patterns related to motor subtypes of Parkinson's disease.

Cerebellar dysfunction may substantially contribute to the clinical symptoms of Parkinson's disease (PD). The role of cerebellar subregions in tremors and gait disturbances in PD remains unknown. To investigate alterations in cerebellar subregion volumes and functional connectivity (FC), as well as FC between the dentate nucleus (DN) and ventral lateral posterior nucleus (VLp) of the thalamus, which are potentially involved in different PD motor subtypes. We conducted morphometric and resting-state functional connectivity analyses in various cerebellar subregions in 22 tremor-dominant (TD)-PD and 35 postural instability gait difficulty dominant (PIGD)-PD patients and 38 sex- and age-matched healthy controls (HCs). The volume and FC alterations in various cerebellar subregions and the neural correlates of these changes with the clinical severity scores were investigated. The PIGD-PD group showed greater FC between the right motor cerebellum (CBMm) and left postcentral gyrus than the HC group, and a higher FC was associated with less severe PIGD symptoms. In contrast, the TD-PD group had decreased FC between the right DN and left VLp compared with the PIGD-PD and HC groups, and lower FC was associated with worse TD symptoms. Furthermore, the PIGD-PD group had higher FC between the left DN and left inferior temporal gyrus than the TD-PD group. Morphometric analysis revealed that the TD-PD group showed a significantly higher volume of left CBMm than the HC group. Our findings point to differential alteration patterns in cerebellar subregions and offer a new perspective on the pathophysiology of motor subtypes of PD.

Comparison of Toxicities among Different Bumped Kinase Inhibitor Analogs for Treatment of Cryptosporidiosis.

Recent advances on the development of bumped kinase inhibitors for treatment of cryptosporidiosis have focused on the 5-aminopyrazole-4-carboxamide scaffold, due to analogs that have less hERG inhibition, superior efficacy, and strong in vitro safety profiles. Three compounds, BKI-1770, -1841, and -1708, showed strong efficacy in C. parvum infected mice. Both BKI-1770 and BKI-1841 had efficacy in the C. parvum newborn calf model, reducing diarrhea and oocyst excretion. However, both compounds caused hyperflexion of the limbs seen as dropped pasterns. Toxicity experiments in rats and calves dosed with BKI-1770 showed enlargement of the epiphyseal growth plate at doses only slightly higher than the efficacious dose. Mice were used as a screen to check for bone toxicity, by changes to the tibia epiphyseal growth plate, or neurological causes, by use of a locomotor activity box. These results showed neurological effects from both BKI-1770 and BKI-1841 and bone toxicity in mice from BKI-1770, indicating one or both effects may be contributing to toxicity. However, BKI-1708 remains a viable treatment candidate for further evaluation as it showed no signs of bone toxicity or neurological effects in mice.

Disulfiram enhances cisplatin cytotoxicity by forming a novel platinum chelate Pt(DDTC)3.

Despite the use of targeted therapy in non-small cell lung cancer (NSCLC) patients, cisplatin (DDP)-based chemotherapy is still the main option. However, DDP resistance is the major factor contributing to the failure of chemotherapy. In this study, we tried to screen DDP sensitizers from an FDA-approved drug library containing 1374 small-molecule drugs to overcome DDP resistance in NSCLC. As a result, disulfiram (DSF) was identified as a DDP sensitizer: DSF and DDP had synergistic anti-NSCLC effects, which are mainly reflected in inhibiting tumor cell proliferation, plate colony formation and 3D spheroidogenesis and inducing apoptosis in vitro, as well as the growth of NSCLC xenografts in mice. Although DSF has recently been reported to promote the antitumor effect of DDP by inhibiting ALDH activity or modulating some important factors or pathways, unexpectedly, we found that DSF reacted with DDP to form a new platinum chelate, Pt(DDTC)3+, which might be one of the important mechanisms for their synergistic effect. Moreover, Pt(DDTC)3+ has a stronger anti-NSCLC effect than DDP, and its antitumor activity is broad-spectrum. These findings reveal a novel mechanism underlying the synergistic antitumor effect of DDP and DSF, and provide a drug candidate or a lead compound for the development of a new antitumor drug.

MCPIP1 Suppresses the NF-κB Signaling Pathway Through Negative Regulation of K63-Linked Ubiquitylation of TRAF6 in Colorectal Cancer.

The abnormal activation of the nuclear factor-kappa B (NF-κB) signaling pathway is an important precipitating factor for the inception and development of colorectal cancer (CRC), one of the most common tumors worldwide. As a pro-apoptotic transcription factor, monocyte chemotactic protein-induced protein 1 (MCPIP1) has been closely associated with many tumor types. In the present study, the expression of MCPIP1 was firstly discovered reduced in CRC tissues and correlated with poor patient prognosis. The decreased expression was caused by promoter hypermethylation. Overexpressed MCPIP1 was found to inhibit the proliferative and migratory abilities of CRC cells, whereas knockdown of MCPIP1 produced the opposite result. The subsequent investigation demonstrated that MCPIP1 exerted its "anti-cancer" effect by suppression of the NF-κB signaling pathway through negative regulation of K63-linked ubiquitylation of TNF receptor associated factor 6 (TRAF6). Therefore, our results indicate a prognostic marker for CRC and a theoretical basis for MCPIP1 as a treatment.

Epithelial-mesenchymal transition classification of circulating tumor cells predicts clinical outcomes in progressive nasopharyngeal carcinoma.

Background: Liquid biopsy facilitates the enrichment and isolation of circulating tumor cells (CTCs) in various human cancers, including nasopharyngeal carcinoma (NPC). Characterizing CTCs allows observation of the evolutionary process of single tumor cells undergoing blood-borne dissemination, such as epithelial-mesenchymal transition. However, the prognostic value of phenotypic classification of CTCs in predicting the clinical outcomes of NPC remains poorly understood. Patients and methods: A total of 92 patients who met the inclusion criteria were enrolled in the present study. The CanPatrol™ CTC technology platform was employed to isolate CTCs, and an RNA in situ hybridization-based system was used for phenotypic classification. Kaplan-Meier survival curves were used for univariate survival analysis, and the log-rank test was performed for between-group comparisons of the survival curves. Results: CTCs were detected in 88.0% (81/92) of the enrolled patients with NPC. The total CTC number did not vary between the T and N stages or between Epstein-Barr virus DNA-positive and -negative cases. The numbers of total CTCs and epithelial/mesenchymal (E/M) hybrid CTCs decreased significantly at 3 months post concurrent chemoradiotherapy (P=0.008 and P=0.023, respectively), whereas the numbers of epithelial or mesenchymal CTCs did not decrease. E/M hybrid-predominant cases had lower disease-free survival (P=0.043) and distant metastasis-free survival (P=0.046) rates than non-E/M hybrid-predominant cases. Conclusion: CTC classification enables a better understanding of the cellular phenotypic alterations responsible for locoregional invasion and distant metastasis in NPC. E/M hybrid-predominant CTC distribution predicts unfavorable clinical outcomes in patients with progressive NPC.

Analysis and Validation of Key Genes Related to Radiosensitivity in Prostate Cancer.

PURPOSE: To investigate the potential relationship between differential gene expression, biological function enrichment, and disease prognosis affecting the sensitivity of prostate cancer radiotherapy by bioinformatics analysis. MATERIALS AND METHODS: Retrieve and obtain data on differential gene expression of prostate cancer radiosensitivity in the GEO database (GSM3954350, GSM3954351, GSM3954352), GER2 tool to screen and analyze the differential genes, Enrichr database for enrichment analysis of GO and KEGG, use Cytoscape software builds protein-protein interaction (PPI) networks and analyzes key genes. RESULTS: A total of 7041 differentially expressed genes were screenedout, including 3842 high expression genes and 3199 low expressed genes. The top 20 differentially expressed genes were selected for further analysis. Their biological functions are mainly enriched in the following aspects: "Cell communication" and "Signal transduction"; cytological components are mainly located outside the cell; molecular functions are enriched in structural molecular activity, receptor binding, serine-like peptidase activity, etc. The KEGG enrichment analysis showed that the differentially expressed genes were mainly enriched in the mismatch repair pathway, non-homologous terminal binding pathway and so on. Survival analysis showed that VGF gene was associated with the prognosis of prostate cancer patients receiving radiotherapy, and high expression of VGF significantly reduced progression-free survival(PFS) in these patients(HR = 4.84, 95% CI: 1.34-17.5, P = .016). CONCLUSION: This study identified key genes associated with radiation sensitivity in prostate cancer and verified the relationship between the VGF gene and patient prognosis.

CMTM6 and PD-L1 coexpression is associated with an active immune microenvironment and a favorable prognosis in colorectal cancer.

BACKGROUND: CKLF-like MARVEL transmembrane domain-containing 6 (CMTM6), a programmed death-ligand 1 (PD-L1) regulator, is widely expressed in various tumors and regulates the immune microenvironment. However, its prognostic value remains controversial, and the roles of CMTM6 in colorectal cancer (CRC) are still unknown. In this study, we aimed to elaborate the expression patterns of CMTM6 and PD-L1 in CRC and investigate their relationship with the infiltration of T cells and the prognosis of patients with CRC. METHODS: Analysis of CMTM6 mRNA levels, gene ontology enrichment analysis and single-sample gene set enrichment analysis were performed in a The Cancer Genome Atlas colon cancer cohort. The expression of CMTM6 and PD-L1 and the infiltration of T cells in tumor tissues from our cohort containing 156 patients with CRC receiving adjuvant chemotherapy and 77 patients with CRC without chemotherapy were examined by immunohistochemistry assay. RESULTS: CMTM6 expression was upregulated in CRC compared with normal colon tissues, and CMTM6 levels were lower in advanced tumors than in early-stage tumors. High expression of CMTM6 correlated with lower pT stage and more CD4+/CD8+ tumor-infiltrating lymphocytes (TILs) and predicted a favorable prognosis in CRC. PD-L1 was expressed in CRC tissues at a low level, and PD-L1 positivity in tumor stroma (PD-L1(TS)), but not PD-L1 positivity in cancer cells (PD-L1(CC)), was associated with an increased density of CD4+ TILs and a favorable prognosis. The coexpression status of CMTM6 and PD-L1(TS) divided patients with CRC into three groups with low, moderate and high risks of progression and death, and patients with CMTM6High/PD-L1(TS)+ status had the longest survival. Moreover, the prognostic value of CMTM6/PD-L1 expression was more significant in patients with CRC treated with adjuvant chemotherapy than in those not treated with chemotherapy. CONCLUSION: CMTM6 has a critical impact on the immune microenvironment and can be used as an independent prognostic factor for CRC. The coexpression status of CMTM6 and PD-L1 can be used as a new classification to stratify the risk of progression and death for patients with CRC, especially for patients receiving adjuvant chemotherapy. These findings may provide insights into improving responses to immunotherapy-included comprehensive treatment for CRC in the future.

One health therapeutics: Target-Based drug development for cryptosporidiosis and other apicomplexa diseases.

This is a review of the development of bumped-kinase inhibitors (BKIs) for the therapy of One Health parasitic apicomplexan diseases. Many apicomplexan infections are shared between humans and livestock, such as cryptosporidiosis and toxoplasmosis, as well as livestock only diseases such as neosporosis. We have demonstrated proof-of-concept for BKI therapy in livestock models of cryptosporidiosis (newborn calves infected with Cryptosporidium parvum), toxoplasmosis (pregnant sheep infected with Toxoplasma gondii), and neosporosis (pregnant sheep infected with Neospora caninum). We discuss the potential uses of BKIs for the treatment of diseases caused by apicomplexan parasites in animals and humans, and the improvements that need to be made to further develop BKIs.

Comparative assessment of the effects of bumped kinase inhibitors on early zebrafish embryo development and pregnancy in mice.

Bumped kinase inhibitors (BKIs) are effective against a variety of apicomplexan parasites. Fifteen BKIs with promising in vitro efficacy against Neospora caninum tachyzoites, low cytotoxicity in mammalian cells, and no toxic effects in non-pregnant BALB/c mice were assessed in pregnant mice. Drugs were emulsified in corn oil and were applied by gavage for 5 days. Five BKIs did not affect pregnancy, five BKIs exhibited ~15-35% neonatal mortality and five compounds caused strong effects (infertility, abortion, stillbirth and pup mortality). Additionally, the impact of these compounds on zebrafish (Danio rerio) embryo development was assessed by exposing freshly fertilised eggs to 0.2-50 µM of BKIs and microscopic monitoring of embryo development in a blinded manner for 4 days. We propose an algorithm that includes quantification of malformations and embryo deaths, and established a scoring system that allows the calculation of an impact score (Si) indicating at which concentrations BKIs visibly affect zebrafish embryo development. Comparison of the two models showed that for nine compounds no clear correlation between Si and pregnancy outcome was observed. However, the three BKIs affecting zebrafish embryos only at high concentrations (≥40 µM) did not impair mouse pregnancy at all, and the three compounds that inhibited zebrafish embryo development already at 0.2 µM showed detrimental effects in the pregnancy model. Thus, the zebrafish embryo development test has limited predictive value to foresee pregnancy outcome in BKI-treated mice. We conclude that maternal health-related factors such as cardiovascular, pharmacokinetic and/or bioavailability properties also contribute to BKI-pregnancy effects.

Protective role of NRF2 in macrovascular complications of diabetes.

Macrovascular complications develop in over a half of the diabetic individuals, resulting in high morbidity and mortality. This poses a severe threat to public health and a heavy burden to social economy. It is therefore important to develop effective approaches to prevent or slow down the pathogenesis and progression of macrovascular complications of diabetes (MCD). Oxidative stress is a major contributor to MCD. Nuclear factor (erythroid-derived 2)-like 2 (NRF2) governs cellular antioxidant defence system by activating the transcription of various antioxidant genes, combating diabetes-induced oxidative stress. Accumulating experimental evidence has demonstrated that NRF2 activation protects against MCD. Structural inhibition of Kelch-like ECH-associated protein 1 (KEAP1) is a canonical way to activate NRF2. More recently, novel approaches, such as activation of the Nfe2l2 gene transcription, decreasing KEAP1 protein level by microRNA-induced degradation of Keap1 mRNA, prevention of proteasomal degradation of NRF2 protein and modulation of other upstream regulators of NRF2, have emerged in prevention of MCD. This review provides a brief introduction of the pathophysiology of MCD and the role of oxidative stress in the pathogenesis of MCD. By reviewing previous work on the activation of NRF2 in MCD, we summarize strategies to activate NRF2, providing clues for future intervention of MCD. Controversies over NRF2 activation and future perspectives are also provided in this review.

GREMA: modelling of emulated gene regulatory networks with confidence levels based on evolutionary intelligence to cope with the underdetermined problem.

MOTIVATION: Non-linear ordinary differential equation (ODE) models that contain numerous parameters are suitable for inferring an emulated gene regulatory network (eGRN). However, the number of experimental measurements is usually far smaller than the number of parameters of the eGRN model that leads to an underdetermined problem. There is no unique solution to the inference problem for an eGRN using insufficient measurements. RESULTS: This work proposes an evolutionary modelling algorithm (EMA) that is based on evolutionary intelligence to cope with the underdetermined problem. EMA uses an intelligent genetic algorithm to solve the large-scale parameter optimization problem. An EMA-based method, GREMA, infers a novel type of gene regulatory network with confidence levels for every inferred regulation. The higher the confidence level is, the more accurate the inferred regulation is. GREMA gradually determines the regulations of an eGRN with confidence levels in descending order using either an S-system or a Hill function-based ODE model. The experimental results showed that the regulations with high-confidence levels are more accurate and robust than regulations with low-confidence levels. Evolutionary intelligence enhanced the mean accuracy of GREMA by 19.2% when using the S-system model with benchmark datasets. An increase in the number of experimental measurements may increase the mean confidence level of the inferred regulations. GREMA performed well compared with existing methods that have been previously applied to the same S-system, DREAM4 challenge and SOS DNA repair benchmark datasets. AVAILABILITY AND IMPLEMENTATION: All of the datasets that were used and the GREMA-based tool are freely available at https://nctuiclab.github.io/GREMA. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Bumped Kinase Inhibitors as therapy for apicomplexan parasitic diseases: lessons learned.

Bumped Kinase Inhibitors, targeting Calcium-dependent Protein Kinase 1 in apicomplexan parasites with a glycine gatekeeper, are promising new therapeutics for apicomplexan diseases. Here we will review advances, as well as challenges and lessons learned regarding efficacy, safety, and pharmacology that have shaped our selection of pre-clinical candidates.

Reprograming the tumor immunologic microenvironment using neoadjuvant chemotherapy in osteosarcoma.

Tumor-infiltrating immune cells play a crucial role in tumor progression and response to treatment. However, the limited studies on infiltrating immune cells have shown inconsistent and even controversial results for osteosarcoma (OS). In addition, the dynamic changes of infiltrating immune cells after neoadjuvant chemotherapy are largely unknown. We downloaded the RNA expression matrix and clinical information of 80 OS patients from the TARGET database. CIBERSORT was used to evaluate the proportion of 22 immune cell types in patients based on gene expression data. M2 macrophages were found to be the most abundant immune cell type and were associated with improved survival in OS. Another cohort of pretreated OS samples was evaluated by immunohistochemistry to validate the results from CIBERSORT analysis. Matched biopsy and surgical samples from 27 patients were collected to investigate the dynamic change of immune cells and factors before and after neoadjuvant chemotherapy. Neoadjuvant chemotherapy was associated with increased densities of CD3+ T cells, CD8+ T cells, Ki67 + CD8+ T cells and PD-L1+ immune cells. Moreover, HLA-DR-CD33+ myeloid-derived suppressive cells (MDSC) were decreased after treatment. We determined that the application of chemotherapy may activate the local immune status and convert OS into an immune "hot" tumor. These findings provide rationale for investigating the schedule of immunotherapy treatment in OS patients in future clinical trials.

MicroRNA-200a improves diabetic endothelial dysfunction by targeting KEAP1/NRF2.

Over a half of the diabetic individuals develop macrovascular complications that cause high mortality. Oxidative stress (OS) promotes endothelial dysfunction (ED) which is a critical early step toward diabetic macrovascular complications. Nuclear factor erythroid 2-related factor 2 (NRF2) is a master regulator of cellular antioxidant defense system and combats diabetes-induced OS. Previously, we found that impaired NRF2 antioxidant signaling contributed to diabetes-induced endothelial OS and dysfunction in mice. The present study has investigated the effect of microRNA-200a (miR-200a) on NRF2 signaling and diabetic ED. In aortic endothelial cells (ECs) isolated from C57BL/6 wild-type (WT) mice, high glucose (HG) reduced miR-200a levels and increased the expression of kelch-like ECH-associated protein 1 (Keap1) - a target of miR-200a and a negative regulator of NRF2. This led to the inactivation of NRF2 signaling and exacerbation of OS and inflammation. miR-200a mimic (miR-200a-M) or inhibitor modulated KEAP1/NRF2 antioxidant signaling and manipulated OS and inflammation under HG conditions. These effects were completely abolished by knockdown of Keap1, indicating that Keap1 mRNA is a major target of miR-200a. Moreover, the protective effect of miR-200a-M was completely abrogated in aortic ECs isolated from C57BL/6 Nrf2 knockout (KO) mice, demonstrating that NRF2 is required for miR-200a's actions. In vivo, miR-200a-M inhibited aortic Keap1 expression, activated NRF2 signaling, and attenuated hyperglycemia-induced OS, inflammation and ED in the WT, but not Nrf2 KO, mice. Therefore, the present study has uncovered miR-200a/KEAP1/NRF2 signaling that controls aortic endothelial antioxidant capacity, which protects against diabetic ED.

Structure-guided discovery of selective methionyl-tRNA synthetase inhibitors with potent activity against Trypanosoma brucei.

Based on crystal structures of Trypanosoma brucei methionyl-tRNA synthetase (TbMetRS) bound to inhibitors, we designed, synthesized, and evaluated two series of novel TbMetRS inhibitors targeting this parasite enzyme. One series has a 1,3-dihydro-imidazol-2-one containing linker, the other has a rigid fused aromatic ring in the linker. For both series of compounds, potent inhibition of parasite growth was achieved with EC50 < 10 nM and most compounds exhibited low general toxicity to mammalian cells with CC50s > 20 000 nM. Selectivity over human mitochondrial methionyl tRNA synthetase was also evaluated, using a cell-based mitochondrial protein synthesis assay, and selectivity in a range of 20-200-fold was achieved. The inhibitors exhibited poor permeability across the blood brain barrier, necessitating future efforts to optimize the compounds for use in late stage human African trypanosomiasis.

Association of Toll-like 4 receptor gene polymorphism (rs4986790, rs4986791) with the risk of urinary tract infection: A systematic review and meta-analysis.

Recently published studies had shown that there may be a potential link between the Single nucleotide polymorphism (SNP) of Toll-like receptor-4 (TLR4), and the risk of urinary tract infection (UTI); however, no consensus was reached. To further understand the relationship between TLR SNPs and urinary tract infections, we searched for related studies published in PubMed, EMBASE, and Web of Science before October 30, 2018, for further systematic review and meta-analysis. Our study accrued 10 case-control studies, which included 1476 urinary tract infection patients and 1449 healthy controls in TLR4(rs4986790, rs4986791). R3.4.2 and Stata 15.0 software were used for the analysis. In general, there was no statistically significant association between rs4986790 and urinary tract infection in the four genetic models. However, in the subgroup analysis, the Asian population showed significantly difference in the allelic model (G vs A: OR = 1.88 [95% CI:1.42-2.49], P = .03). In addition, there were also significant differences in the dominant model (GG + AG vs AA OR = 1.97 [95% CI:1.46-2.66], P = .01). Due to the small number of available literatures, no meaningful conclusion can be drawn regarding the relationship between TLR4 (rs4986791) and the risk of urinary tract infections in general. Nevertheless, our meta-analysis shows that in Asian populations, TLR4 (rs4986790) may be associated with risk of urinary tract infection.

Genome-wide RNAi Screening Identifies RFC4 as a Factor That Mediates Radioresistance in Colorectal Cancer by Facilitating Nonhomologous End Joining Repair.

PURPOSE: Neoadjuvant chemoradiotherapy (neoCRT) is a standard treatment for locally advanced rectal cancer (LARC); however, resistance to chemoradiotherapy is one of the main obstacles to improving treatment outcomes. The goal of this study was to identify factors involved in the radioresistance of colorectal cancer and to clarify the underlying mechanisms. EXPERIMENTAL DESIGN: A genome-wide RNAi screen was used to search for candidate radioresistance genes. After RFC4 knockdown or overexpression, colorectal cancer cells exposed to X-rays both in vitro and in a mouse model were assayed for DNA damage, cytotoxicity, and apoptosis. Moreover, the regulatory effects and mechanisms of RFC4 in DNA repair were investigated in vitro. Finally, the relationships between RFC4 expression and clinical parameters and outcomes were investigated in 145 patients with LARC receiving neoCRT. RESULTS: RFC4, NCAPH, SYNE3, LDLRAD2, NHP2, and FICD were identified as potential candidate radioresistance genes. RFC4 protected colorectal cancer cells from X-ray-induced DNA damage and apoptosis in vitro and in vivo. Mechanistically, RFC4 promoted nonhomologous end joining (NHEJ)-mediated DNA repair by interacting with Ku70/Ku80 but did not affect homologous recombination-mediated repair. Higher RFC4 expression in cancer tissue was associated with weaker tumor regression and poorer prognosis in patients with LARC treated with neoCRT, which likely resulted from the effect of RFC4 on radioresistance, not chemoresistance. CONCLUSIONS: RFC4 was identified as a radioresistance factor that promotes NHEJ-mediated DNA repair in colorectal cancer cells. In addition, the expression level of RFC4 predicted radiotherapy responsiveness and the outcome of neoadjuvant radiotherapy in patients with LARC.

P53/NRF2 mediates SIRT1's protective effect on diabetic nephropathy.

Diabetic nephropathy (DN) is the leading cause of end stage renal disease, posing a severe threat to public health. Previous studies reported the protective role of sirtuin 1 (SIRT1) in DN, encouraging the investigation of more potent and specific SIRT1 activators. SRT2104 is a novel, first-in-class, highly selective small-molecule activator of SIRT1, with its effect and mechanism unknown on DN. To this end, streptozotocin-induced C57BL/6 wild-type (WT) diabetic mice were treated with SRT2104, for 24 weeks. To determine whether SRT2104 acted through inhibition of P53 - a substrate of SIRT1, the P53 activator nutlin3a was administered to the WT diabetic mice in the presence of SRT2104. In order to test whether nuclear factor erythroid 2-related factor 2 (NRF2) - the master of cellular antioxidants - mediated SIRT1 and P53's actions, WT and Nrf2 gene knockout (KO) diabetic mice were treated with SRT2104 or the P53 inhibitor pifithrin-α (PFT-α). In the WT mice, SRT2104 enhanced renal SIRT1 expression and activity, deacetylated P53, and activated NRF2 antioxidant signaling, providing remarkable protection against the DM-induced renal oxidative stress, inflammation, fibrosis, glomerular remodeling and albuminuria. These effects were completely abolished in the presence of nutlin3a. Deletion of the Nrf2 gene completely abrogated the efficacies of SRT2104 and PFT-α in elevating antioxidants and ameliorating DN, despite their abilities to activate SIRT1 and inhibit P53 in the Nrf2 KO mice. The present study reports the beneficial effects of SRT2104 on DN, uncovering a SIRT1/P53/NRF2 pathway that modulates the pathogenesis of DN.