SHF confers radioresistance in colorectal cancer by the regulation of mitochondrial DNA copy number.

Altered mitochondrial function contributes greatly to pathogenesis and progression of colorectal cancer. In this study, we report a functional pool of Src homology 2 domain-containing F (SHF) in mitochondria controlling the response of colorectal cancer cells to radiation therapy. We found that elevated expression of SHF in cancer cells is essential for promoting mitochondrial function by increasing mitochondrial DNA copy number, thus reducing the sensitivity of colorectal cancer cells to radiation. Mechanistically, SHF binds to mitochondrial DNA and promotes POLG/SSBP1-mediated mitochondrial DNA synthesis. Importantly, SHF loss-mediated radiosensitization was phenocopied by depletion of mitochondrial DNA. Thus, our data demonstrate that mitochondrial SHF is an important regulator of radioresistance in colorectal cancer cells, identifying SHF as a promising therapeutic target to enhance radiotherapy efficacy in colorectal cancer.

FKBP4 regulates 5-fluorouracil sensitivity in colon cancer by controlling mitochondrial respiration.

Mitochondrial respiration and metabolism play a key role in the pathogenesis and progression of colon adenocarcinoma (COAD). Here, we report a functional pool of FKBP4, a co-chaperone protein, in the mitochondrial intermembrane space (IMS) of colon cancer cells. We found that IMS-localized FKBP4 is essential for the maintenance of mitochondrial respiration, thus contributing to the sensitivity of COAD cells to 5-fluorouracil (5-FU). Mechanistically, FKBP4 interacts with COA6 and controls the assembly of the mitochondrial COA6/SCO1/SCO2 complex, thereby governing COA6-regulated biogenesis and activity of mitochondrial cytochrome c oxidase (complex IV). Thus, our data reveal IMS-localized FKBP4 as a novel regulator of 5-FU sensitivity in COAD, linking mitochondrial respiration to 5-FU sensitivity in COAD.

A novel mitochondria-related gene signature for controlling colon cancer cell mitochondrial respiration and proliferation.

Colon cancer cells rely on mitochondrial respiration as major source of energy for supporting their proliferation and invasion, thus promoting colon cancer malignancy and progression. In this study, we comprehensively investigated the prognostic significance of mitochondria-related genes in colon cancer and identified the hub genes that control colon cancer cell mitochondrial respiration and proliferation. We first systematically evaluated the prognostic significance of differentially expressed mitochondria-related genes in colon cancer specimens. Furthermore, a protein-protein interaction network was constructed to explore the hub genes. Eventually, five hub genes were identified, namely, POLG, FASTK, MRPS5, AARS2, and VARS2. Functional analyses showed that all these five hub genes are essential for maintaining mitochondrial respiration and proliferation of colon cancer cells. Mechanistic studies revealed the roles of these five hub genes in modulating mitochondrial DNA expression, that in turn influence mitochondrial respiration. In summary, our study demonstrated that POLG, FASTK, MRPS5, AARS2, and VARS2 may potentially serve as prognostic biomarkers and therapeutic targets for colon cancer.

Environmentally-extended input-output and ecological network analysis for Energy-Water-CO2 metabolic system in China.

Resource and environmental elements as controlling factors for ecologic and socio-economic are crucial to seek new ideas and paths for development and prosperity. In this study, environmentally-extended input-output analysis and ecological network analysis were combined to develop three ecological networks including energy ecological network, water ecological network, and carbon ecological network for searching the complex relationships among different departments for water utilization, energy consumption, and carbon emissions under considering China as a superorganism with various complex metabolic processes and the most fundamental metabolic materials. The embodied ecological elements intensity, the indirect consumption and emissions, the embodied material flows, the ecological relationships, and the dependence intensities among sectors was obtained through transforming the monetary input-output data to physical data from 2007, 2012, and 2017. The results show that the Energy Ecological Network and Water Ecological Network were in a relatively stable state with a mutualism index greater than 1, and the relationship among different sectors in the CO2 Ecological Network needs to be further adjusted. AM (Advanced Manufacture) and Agr (Agriculture) played the top exporter and importer roles with AM as the largest embodied energy consumer and CO2 emitter, and Agr as the largest embodied water user. More measures about resource conservation and emission reduction for AM and Agr are desired. Con (construction) had a strong dependence intensity on other sectors with amounts of over 90%. Resources and environmental effects on Con can be improved by increasing the utilization efficiency of intermediate products. The results could provide scientific policy implications and guidelines to promote the stable and healthy operations by revealing the dynamic change of sectors within the Energy-Water-CO2 metabolic system in China.

Revealing potential immunotherapy targets through analysis of a ceRNA network in human colon adenocarcinoma.

BACKGROUND: Microsatellite instability-high (MSI-H) is a special type of human colon adenocarcinoma (COAD) that responds well to immunotherapy. MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs), which are important members of competing endogenous RNAs (ceRNAs) networks, are involved in the tumorigenesis and development of MSI-H COAD. This study aimed to establish a ceRNA network for MSI in COAD to identify targets and prognostic markers that may explain the effects of immunotherapy. METHODS: COAD sequencing data were extracted from The Cancer Genome Atlas (TCGA), after which differentially expressed miRNAs, lncRNAs, and mRNAs were determined according to microsatellite status. After building a network based on the ceRNA hypothesis, the relationships between microsatellite status and clinical features were explored. Biological processes in the Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) databases were analyzed for specific miRNAs, lncRNAs, and mRNAs. Survival analysis was used to identify potential biomarkers. RESULTS: Based on the inclusion criteria, a total of 363 COAD samples were obtained from TCGA. Strict screening criteria were used to identify differentially expressed RNAs in the MSI-H and microsatellite-stable groups, with 82 miRNAs, 1,280 lncRNAs, and 2121 mRNAs obtained (fold change >2, false discovery rate <0.01). Based on the RNA interaction mechanism, a miRNA-lncRNA-mRNA network was constructed, through which a subnetwork composed of 5 miRNAs was discovered. hsa-miR-31-5p, hsa-miR-302a-3p, hsa-miR-302b-3p, hsa-miR-302d-3p, hsa-miR-3619-5p and the RNAs interaction with them have the potential to become novel targets to change the effect of existing immunotherapy. GO and KEGG analyses showed that these differentially expressed miRNAs, lncRNAs, and mRNAs may play key roles in tumorigenesis, tumor development, and drug efficacy, with natural killer cells potentially becoming the next emerging targets for immunotherapy enhancement. Moreover, survival analysis identified 10 lncRNAs as potential survival markers. CONCLUSIONS: This study identified novel immunotherapy targets and revealed potential biomarkers for COAD according to microsatellite status.

c.1439delA frameshift deletion mutation in familial adenomatous polyposis.

Familial adenomatous polyposis (FAP) is a rare autosomal dominant genetic disease related to germline mutations of the APC gene. The clinical features of this disease most commonly include hundreds of adenomas or polyps. If not treated in a timely fashion, FAP can eventually result in colorectal carcinoma. In this report, clinical manifestations, family history, relevant auxiliary examinations and gene detection from patient blood led us to discover a novel frameshift mutation in exon 12 of the APC gene. The deletion of adenine in c.1439 resulted in the formation of codon 480. The occurrence of this frameshift deletion may lead to inexpressibility of the main functional regions in APC and may affect gene function. In addition, colonoscopy and histopathology showed malignant changes in the colon and rectum. There have been no reports of this frameshift mutation, but it can be considered in case of APC mutations and FAP in patients with clinical manifestations; auxiliary examination may be related, and it may be used as a reference for preventive clinical treatment in the future.

Mitochondrial DNA D­loop lesions with the enhancement of DNA repair contribute to gastrointestinal cancer progression.

Gastrointestinal cancer (GIC) is a worldwide public health problem with a high mortality rate. Mitochondrial DNA (mtDNA) mutations in the displacement loop (D­loop) region are quite common in various types of primary human cancers; however, their role in the pathogenesis of GIC is controversial. In the present study, tumor and para­tumor tissues were selected from 18 patients with gastric cancer (GC), 21 patients with colon cancer (CC) and 30 patients with rectal cancer (RC). The mtDNA D­loop was analyzed by sequencing and reverse transcription­quantitative polymerase chain reaction. Furthermore, DNA oxidative damage and DNA repair functioning were detected by immunohistochemistry. The results demonstrated that increased mtDNA deletion was not evident in GIC; however, significant DNA oxidative damage was significant in RC by detecting 8­hydroxyguanine expression. In addition, over­activated DNA repair was identified in CC and RC through the detection of 8­oxo­20­deoxyguanosine glycosylase 1 expression. The mtDNA D­loop had a specific mutation hotspot region, and the level of mtDNA D­loop mutations was correlated with the progression of the GIC. The mutations of the mtDNA D­loop were primarily homoplasmic in GIC and often transitioned at pyrimidine sites. Mitochondrial microsatellite instability, including the formation of poly­cytidine stretches, was common in GIC. These results demonstrate the occurrence of mtDNA D­loop mutations in GIC in Chinese patients and support the correlation of these mutations with carcinoma progression. Over­activated DNA repair function possibly repairs the GIC mtDNA lesions.

DRAM Is Involved in Regulating Nucleoside Analog-Induced Neuronal Autophagy in a p53-Independent Manner.

The widespread use of combined anti-retroviral therapy (cART) has not decreased the prevalence of HIV-1-associated neurocognitive disorder (HAND), a type of neurodegenerative disease, even though cART effectively inhibits virus colonization in the central nervous system. Therefore, anti-retroviral agents cannot be fully excluded from the pathogenesis of HAND. Our previous study reported that long-term nucleoside analogue (NA) exposure induced mitochondrial toxicity in the cortical neurons of HAND patients and mice, but the exact mechanism of NA-associated neurotoxicity has remained unclear. Alteration of autophagy can result in protein aggregation and the accumulation of dysfunctional organelles, which are hallmarks of some neurodegenerative diseases. In this study, we first found increased autophagy in cortical autopsy specimens of AIDS patients. We then found that a low dose of NAs could stimulate autophagy in primary cultured neurons, while a high dose of NAs could induce only neuronal apoptosis. The level of NA-induced Bcl-2 and Bax expressions determined whether neuronal autophagy or apoptosis occurred. Furthermore, the level of NA-induced neuronal apoptosis correlated with the dysfunction of cellular DNA polymerase gamma. Damage-regulated autophagy modulator (DRAM) overexpression was also involved in NA-induced neuronal autophagy. p53 played a role in the regulation of NA-induced neuronal apoptosis, but its role in NA-associated neuronal autophagy was uncertain. Our results suggest that DRAM is involved in the regulation of NA-induced neuronal autophagy in a p53-independent manner. Further research is needed to investigate the underlying mechanism.

Fever, Dry Cough and Exertional Dyspnea: Pulmonary Lymphomatoid Granulomatosis Masquerading as Pneumonia, Granulomatosis with Polyangiitis and Infectious Mononucleosis.

Lymphomatoid granulomatosis (LYG) is a rare Epstein-Barr virus-associated lymphoproliferative disorder. The disease lacks specific clinical and radiological manifestations, which may delay a definitive diagnosis. We report the case of a 39-year-old man with pulmonary LYG who presented to a hospital after experiencing three months of fever, weight loss, dry cough and exertional dyspnea. He was initially misdiagnosed with pneumonia, granulomatosis with polyangiitis and infectious mononucleosis due to the non-specific manifestations of the disease. We herein present the clinical and radiological characteristics of this case and discuss the procedure for pathological diagnosis, which will likely help clinicians in making a timely definitive diagnosis of this disease.

[ASPP2 inhibits oxaliplatin-induced autophagy and promotes apoptosis of colon cancer cells].

OBJECTIVE: To investigate the role of apoptosis stimulating p53 binding protein 2 (ASPP2)-induced p53-dependent and p53-independent autophagy inhibition in apoptosis-promoting function of oxaliplatin (OXA). METHODS: According to different treatments, HCT116(p53(-/-)) cells were divided into 6 groups: rapamycin combined with ASPP2 group, ASPP2 group, p53 group, ASPP2 combined with p53 group, OXA combined with 3-methyladenine (3-MA) group, control group (OXA treatment or starvation without OXA treatment). When the level of apoptosis was detected, green fluorescent protein-advirus (GFP-Ad) group and rapamycin group were supplemented as controls. Cells were transfected with GFP-microtubule-associated protein 1 light chain 3 (GFP-LC3) plasmid, and LC3-expressing cells were calculated under a fluorescent microscope. Expressions of autophagy-related molecules were detected by Western blotting. Cells were subjected to annexin V-FITC/PI staining and apoptosis was assessed by flow cytometry. RESULTS: The 3-MA group showed the same inhibitory ability on autophagy with the ASPP2 group, and both of them were able to promote OXA or starvation-induced apoptosis, but the cell apoptosis rate in the 3-MA group was lower than that of the ASPP2 group. Rapamycin combined with ASPP2 still promoted OXA or starvation-induced apoptosis, and the apoptosis rate was also lower than that of the ASPP2 group. However, rapamycin counteracted effectively the inhibitory effect of ASPP2 on autophagy. CONCLUSION: OXA can induce autophagy of colorectal cancer cells, while ASPP2 over-expression can suppress the OXA-induced autophagy. ASPP2 can promote apoptosis through p53-dependent and p53-independent pathways. The function of ASPP2 promoting cell apoptosis through p53-dependent and p53-independent pathways is not entirely achieved by inhibiting cell autophagy.

Mitochondrial DNA D-loop AG/TC transition mutation in cortical neurons of mice after long-term exposure to nucleoside analogues.

With the wide application of combined antiretroviral therapy, the prognosis of human immunodeficiency virus (HIV)-1 infected patient has been significantly improved. However, long-term administration of antiretroviral drugs can result in various drug-associated toxicities. Among them, nucleoside analogues were confirmed to inhibit DNA polymerase gamma, resulting in mitochondrial toxicity. Our previous study indicated that long-term exposure of mice to nucleoside analogue could induce mitochondria DNA (mtDNA) loss in cortical neurons. Herein, we further identify mitochondrial toxicity of four nucleoside analogues (zidovudine (AZT), stavudine (D4T), lamivudine (3TC), and didanosine (DDI)) by cloning and sequencing mtDNA D-loop region in mice neurons captured with laser capture microdissection. The results showed that mutation of neuronal mtDNA D-loop sequences increased in mice treated with each of the four nucleoside analogues for 4 months and D4T and DDI induced more severe D-loop lesion than the other two nucleoside analogues. The major type of D-loop point mutations induced by four nucleoside analogues was transition, in particular of "A→G" and "T→C" transition, but the point transition sites were variable. Our findings suggest that long-term exposure to nucleoside analogue can result in mtDNA D-loop region lesion in mouse cortical neurons.