Identification of COQ2 as a regulator of proliferation and lipid peroxidation through genome-scale CRISPR-Cas9 screening in myeloma cells.

Multiple myeloma (MM) is the second most common malignant haematological disease with a poor prognosis. The limit therapeutic progress has been made in MM patients with cancer relapse, necessitating deeper research into the molecular mechanisms underlying its occurrence and development. A genome-wide CRISPR-Cas9 loss-of-function screening was utilized to identify potential therapeutic targets in our research. We revealed that COQ2 plays a crucial role in regulating MM cell proliferation and lipid peroxidation (LPO). Knockout of COQ2 inhibited cell proliferation, induced cell cycle arrest and reduced tumour growth in vivo. Mechanistically, COQ2 promoted the activation of the MEK/ERK cascade, which in turn stabilized and activated MYC protein. Moreover, we found that COQ2-deficient MM cells increased sensitivity to the LPO activator, RSL3. Using an inhibitor targeting COQ2 by 4-CBA enhanced the sensitivity to RSL3 in primary CD138+ myeloma cells and in a xenograft mouse model. Nevertheless, co-treatment of 4-CBA and RSL3 induced cell death in bortezomib-resistant MM cells. Together, our findings suggest that COQ2 promotes cell proliferation and tumour growth through the activation of the MEK/ERK/MYC axis and targeting COQ2 could enhance the sensitivity to ferroptosis in MM cells, which may be a promising therapeutic strategy for the treatment of MM patients.

Wnt/ß-catenin signalling activates IMPDH2-mediated purine metabolism to facilitate oxaliplatin resistance by inhibiting caspase-dependent apoptosis in colorectal cancer.

BACKGROUND: Oxaliplatin resistance usually leads to therapeutic failure and poor prognosis in colorectal cancer (CRC), while the underlying mechanisms are not yet fully understood. Metabolic reprogramming is strongly linked to drug resistance, however, the role and mechanism of metabolic reprogramming in oxaliplatin resistance remain unclear. Here, we aim to explore the functions and mechanisms of purine metabolism on the oxaliplatin-induced apoptosis of CRC. METHODS: An oxaliplatin-resistant CRC cell line was generated, and untargeted metabolomics analysis was conducted. The inosine 5'-monophosphate dehydrogenase type II (IMPDH2) expression in CRC cell lines was determined by quantitative real-time polymerase chain reaction (qPCR) and western blotting analysis. The effects of IMPDH2 overexpression, knockdown and pharmacological inhibition on oxaliplatin resistance in CRC were assessed by flow cytometry analysis of cell apoptosis in vivo and in vitro. RESULTS: Metabolic analysis revealed that the levels of purine metabolites, especially guanosine monophosphate (GMP), were markedly elevated in oxaliplatin-resistant CRC cells. The accumulation of purine metabolites mainly arose from the upregulation of IMPDH2 expression. Gene set enrichment analysis (GSEA) indicated high IMPDH2 expression in CRC correlates with PURINE_METABOLISM and MULTIPLE-DRUG-RESISTANCE pathways. CRC cells with higher IMPDH2 expression were more resistant to oxaliplatin-induced apoptosis. Overexpression of IMPDH2 in CRC cells resulted in reduced cell death upon treatment with oxaliplatin, whereas knockdown of IMPDH2 led to increased sensitivity to oxaliplatin through influencing the activation of the Caspase 7/8/9 and PARP1 proteins on cell apoptosis. Targeted inhibition of IMPDH2 by mycophenolic acid (MPA) or mycophenolate mofetil (MMF) enhanced cell apoptosis in vitro and decreased in vivo tumour burden when combined with oxaliplatin treatment. Mechanistically, the Wnt/ß-catenin signalling was hyperactivated in oxaliplatin-resistant CRC cells, and a reciprocal positive regulatory mechanism existed between Wnt/ß-catenin and IMPDH2. Blocking the Wnt/ß-catenin pathway could resensitize resistant cells to oxaliplatin, which could be restored by the addition of GMP. CONCLUSIONS: IMPDH2 is a predictive biomarker and therapeutic target for oxaliplatin resistance in CRC.

Tight Junction Protein 1 Suppresses Kidney Renal Clear Cell Carcinoma Cells Proliferation by Inducing Autophagy.

TJP1, an adaptor protein of the adhesive barrier, has been found to exhibit distinct oncogenic or tumor suppressor functions in a cell-type dependent manner. However, the role of TJP1 in kidney renal clear cell carcinoma (KIRC) remains to be explored. The results showed a marked down-regulation of TJP1 in KIRC tissues compared to normal tissues. Low expression of TJP1 was significantly associated with high grade and poor prognosis in KIRC. Autophagosome aggregation and LC3 II conversion demonstrated that TJP1 may induce autophagy signaling in 786-O and OS-RC-2 cells. Knockdown of TJP1 led to a decrease in the expression of autophagy-related genes, such as BECN1, ATG3, and ATG7. Consistently, TJP1 expression showed a significant positive correlation with these autophagy-related genes in KIRC patients. Furthermore, the overall survival analysis of KIRC patients based on the expression of autophagy-related genes revealed that most of these genes were associated with a good prognosis. TJP1 overexpression significantly suppressed cell proliferation and tumor growth in 786-O cells, whereas the addition of an autophagy inhibitor diminished its inhibitory function. Taken together, these results suggest that TJP1 serves as a favorable prognostic marker and induces autophagy to suppress cell proliferation and tumor growth in KIRC.

In situ analysis of surface composition and meteorology at the Zhurong landing site on Mars.

The Zhurong rover of the Tianwen-1 mission landed in southern Utopia Planitia, providing a unique window into the evolutionary history of the Martian lowlands. During its first 110 sols, Zhurong investigated and categorized surface targets into igneous rocks, lithified duricrusts, cemented duricrusts, soils and sands. The lithified duricrusts, analysed by using laser-induced breakdown spectroscopy onboard Zhurong, show elevated water contents and distinct compositions from those of igneous rocks. The cemented duricrusts are likely formed via water vapor-frost cycling at the atmosphere-soil interface, as supported by the local meteorological conditions. Soils and sands contain elevated magnesium and water, attributed to both hydrated magnesium salts and adsorbed water. The compositional and meteorological evidence indicates potential Amazonian brine activities and present-day water vapor cycling at the soil-atmosphere interface. Searching for further clues to water-related activities and determining the water source by Zhurong are critical to constrain the volatile evolution history at the landing site.

Oscillating Fluid Flow Activated Osteocyte Lysate-Based Hydrogel for Regulating Osteoblast/Osteoclast Homeostasis to Enhance Bone Repair.

As major regulators on bone formation/resorption in response to mechanical stimuli, osteocytes have shown great promise for restoring bone injury. However, due to the unmanageable and unabiding cell functions in unloading or diseased environments, the efficacy of osteogenic induction by osteocytes has been enormously limited. Herein, a facile method of oscillating fluid flow (OFF) loading for cell culture is reported, which enables osteocytes to initiate only osteogenesis and not the osteolysis process. After OFF loading, multiple and sufficient soluble mediators are produced in osteocytes, and the collected osteocyte lysates invariably induce robust osteoblastic differentiation and proliferation while restraining osteoclast generation and activity under unloading or pathological conditions. Mechanistic studies confirm that elevated glycolysis and activation of the ERK1/2 and Wnt/ß-catenin pathways are the major contributors to the initiation of osteoinduction functions induced by osteocytes. Moreover, an osteocyte lysate-based hydrogel is designed to establish a stockpile of "active osteocytes" to sustainably deliver bioactive proteins, resulting in accelerated healing through regulation of endogenous osteoblast/osteoclast homeostasis.

Nanoemulsified clove essential oils-based edible coating controls Pseudomonas spp.-causing spoilage of tilapia (Oreochromis niloticus) fillets: Working mechanism and bacteria metabolic responses.

Fish products suffer Pseudomonas-causing spoilage quickly during refrigeration storage, which could be solved by applying edible coating derived from nanoemulsified clove essential oils and fish gelatin (NCEO-FG). This study aimed to evaluate the effects and mechanism of NCEO-FG in preserving tilapia (Oreochromis niloticus) fillets that were inoculated with Pseudomonas spp. (Pseudomonas sp. strain ABa3, P. psychrophila strain ABe3, and P. fragi strain BBa3). NCEO caused remarkable leakage of proteins (198.5-252.8 µg/L) and nucleic acids (0.30-0.34 of OD260). After being incorporated into FG, NCEO-FG effectively delayed the deterioration of tilapia fillets because it significantly reduced the surviving bacteria populations (0.78 - 1.80 log CFU/g reductions) and inhibited the proteolysis and oxidation during cold storage. Further, the metabolic responses of NCEO-FG coated Pseudomonas spp. were revealed using NMR spectroscopy: the reducing levels of metabolites (e.g., pyruvate, amino acids, and betaine) suggested that the NCEO-FG disturbed energy and amino acid metabolisms of bacteria cells. However, the levels of metabolites (e.g., amino acids and osmoprotectants) were upregulated after 3 h and then back to normal concentration after 24 h, which indicated a defense system was built in bacterial cells to tolerate NCEO-FG. In short, this study confirmed that NCEO-FG could control the Pseudomonas-causing spoilage in fish fillets via elucidating the metabolisms.

Case report: ISL2 is involved in malignant transformation in a patient with multiple relapsed oligodendroglioma.

The majority of oligodendrogliomas exhibit an intrinsic tendency to develop into malignant high-grade tumors. Angiogenesis is a major factor contributing to the malignant transformation of oligodendroglioma, and its molecular regulatory mechanism needs further study. We provide a case report of an oligodendroglioma patient with two recurrences whose disease progressed from WHO grade II to grade III. We showed that the expression of insulin gene enhancer protein (ISL2) and its angiogenic ability were positively correlated with the progression of oligodendroglioma. In Low-grade glioma (LGG) patients, including oligodendroglioma patients, overexpression of ISL2 was correlated with poor prognosis, and this correlation was not affected by gender or isocitrate dehydrogenase 1(IDH1) mutation status. ISL2 expression and ISL2-mediated angiogenic pathway activity are ideal biomarkers for the malignant transformation of oligodendroglioma. Anti-ISL2 therapy is also a potential treatment option for malignantly transformed oligodendroglioma.

Metabolic Responses of "Big Six" Escherichia coli in Wheat Flour to Thermal Treatment Revealed by Nuclear Magnetic Resonance Spectroscopy.

Escherichia coli outbreaks linked to wheat flour consumption have kept emerging in recent years, which necessitated an antimicrobial step being incorporated into the flour production process. The objectives of this in vivo study were to holistically evaluate the sanitizing efficacy of thermal treatment at 60 and 70°C against the "big six" E. coli strains (O26:H11, O45:H2, O103:H11, O111, O121:H19, and O145) in wheat flour and to assess the strain-specific metabolic responses using nuclear magnetic resonance (NMR) spectroscopy. The 70°C treatment temperature indiscriminatingly inactivated all strains by over 4.3-log CFU/g within 20 min, suggesting the high sanitization effectiveness of this treatment temperature, whereas the treatment at 60°C inactivated the strains to various degrees during the 1-h process. The most resistant strains at 60°C, O26 and O45, were characterized by amino acid and sugar depletion, and their high resistance was attributed to the dual effects of activated heat shock protein (HSP) synthesis and promoted glycolysis. O121 also demonstrated these metabolic changes, yet its thermal resistance was largely impaired by the weakened membrane structure and diminished osmotic protection due to phosphorylcholine exhaustion. In contrast, O111, O145, and O103 presented a substantial elevation of metabolites after stress at 60°C; their moderate thermal resistance was mainly explained by the accumulation of amino acids as osmolytes. Overall, the study enhanced our understanding of the metabolic responses of big six E. coli to heat stress and provided a model for conducting NMR-based metabolomic studies in powdered food matrices. IMPORTANCE "Big six" Escherichia coli strains have caused several outbreaks linked to wheat flour consumption in the last decade, revealing the vital importance of adopting an antimicrobial treatment during the flour production process. Therefore, the present study was carried out to evaluate the efficacy of a typical sanitizing approach, thermal treatment, against the big six strains in wheat flour along with the underlying antimicrobial mechanisms. Findings showed that thermal treatment at 60 and 70°C could markedly mitigate the loads of all strains in wheat flour. Moreover, activated heat shock protein synthesis combined with expedited glycolysis and enhanced osmotic protection were identified as two major metabolic alteration patterns in the E. coli strains to cope with the heat stress. With the responses of big six in wheat flour to thermal treatment elucidated, scientific basis for incorporating a thermal inactivation step in wheat flour production was provided.

Targeting hexokinase 2 increases the sensitivity of oxaliplatin by Twist1 in colorectal cancer.

Colorectal cancer (CRC) is the third most malignant tumour worldwide, with high mortality and recurrence. Chemoresistance is one of the main factors leading to metastasis and poor prognosis in advanced CRC patients. By analysing the Gene Expression Omnibus data set, we found higher hexokinase 2 (HK2) expression levels in patients with metastatic CRC than in those with primary CRC. Moreover, we observed higher enrichment in oxaliplatin resistance-related gene sets in metastatic CRC than in primary CRC. However, the underlying relationship has not yet been elucidated. In our study, HK2 expression was significantly elevated in CRC patients. Gene set enrichment analysis (GSEA) revealed multi-drug resistance and epithelial-mesenchymal transition (EMT) pathways related to high HK2 expression. Our results showed that knockdown of HK2 significantly inhibited vimentin and Twist1 expression and promoted TJP1 and E-cadherin expression in CRC cells. Additionally, transcriptional and enzymatic inhibition of HK2 by 3-bromopyruvate (3-bp) impaired oxaliplatin resistance in vitro and in vivo. Mechanistically, HK2 interacts with and stabilized Twist1 by preventing its ubiquitin-mediated degradation, which is related to oxaliplatin resistance, in CRC cells. Overexpression of Twist1 reduced the apoptosis rate by HK2 knockdown in CRC cells. Collectively, we discovered that HK2 is a crucial regulator that mediates oxaliplatin resistance through Twist1. These findings identify HK2 and Twist1 as promising drug targets for CRC chemoresistance.