RARRES2 regulates lipid metabolic reprogramming to mediate the development of brain metastasis in triple negative breast cancer.

BACKGROUND: Triple negative breast cancer (TNBC), the most aggressive subtype of breast cancer, is characterized by a high incidence of brain metastasis (BrM) and a poor prognosis. As the most lethal form of breast cancer, BrM remains a major clinical challenge due to its rising incidence and lack of effective treatment strategies. Recent evidence suggested a potential role of lipid metabolic reprogramming in breast cancer brain metastasis (BCBrM), but the underlying mechanisms are far from being fully elucidated. METHODS: Through analysis of BCBrM transcriptome data from mice and patients, and immunohistochemical validation on patient tissues, we identified and verified the specific down-regulation of retinoic acid receptor responder 2 (RARRES2), a multifunctional adipokine and chemokine, in BrM of TNBC. We investigated the effect of aberrant RARRES2 expression of BrM in both in vitro and in vivo studies. Key signaling pathway components were evaluated using multi-omics approaches. Lipidomics were performed to elucidate the regulation of lipid metabolic reprogramming of RARRES2. RESULTS: We found that down-regulation of RARRES2 is specifically associated with BCBrM, and that RARRES2 deficiency promoted BCBrM through lipid metabolic reprogramming. Mechanistically, reduced expression of RARRES2 in brain metastatic potential TNBC cells resulted in increased levels of glycerophospholipid and decreased levels of triacylglycerols by regulating phosphatase and tensin homologue (PTEN)-mammalian target of rapamycin (mTOR)-sterol regulatory element-binding protein 1 (SREBP1) signaling pathway to facilitate the survival of breast cancer cells in the unique brain microenvironment. CONCLUSIONS: Our work uncovers an essential role of RARRES2 in linking lipid metabolic reprogramming and the development of BrM. RARRES2-dependent metabolic functions may serve as potential biomarkers or therapeutic targets for BCBrM.

MTA1, a Novel ATP Synthase Complex Modulator, Enhances Colon Cancer Liver Metastasis by Driving Mitochondrial Metabolism Reprogramming.

Liver metastasis is the most fatal event of colon cancer patients. Warburg effect has been long challenged by the fact of upregulated oxidative phosphorylation (OXPHOS), while its mechanism remains unclear. Here, metastasis-associated antigen 1 (MTA1) is identified as a newly identified adenosine triphosphate (ATP) synthase modulator by interacting with ATP synthase F1 subunit alpha (ATP5A), facilitates colon cancer liver metastasis by driving mitochondrial bioenergetic metabolism reprogramming, enhancing OXPHOS; therefore, modulating ATP synthase activity and downstream mTOR pathways. High-throughput screening of an anticancer drug shows MTA1 knockout increases the sensitivity of colon cancer to mitochondrial bioenergetic metabolism-targeted drugs and mTOR inhibitors. Inhibiting ATP5A enhances the sensitivity of liver-metastasized colon cancer to sirolimus in an MTA1-dependent manner. The therapeutic effects are verified in xenograft models and clinical cases. This research identifies a new modulator of mitochondrial bioenergetic reprogramming in cancer metastasis and reveals a new mechanism on upregulating mitochondrial OXPHOS as the reversal of Warburg effect in cancer metastasis is orchestrated.

PRR15 deficiency facilitates malignant progression by mediating PI3K/Akt signaling and predicts clinical prognosis in triple-negative rather than non-triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast neoplasms with a higher risk of recurrence and metastasis than non-TNBC. Nevertheless, the factors responsible for the differences in the malignant behavior between TNBC and non-TNBC are not fully explored. Proline rich 15 (PRR15) is a protein involved in the progression of several tumor types, but its mechanisms are still controversial. Therefore, this study aimed to investigate the biological role and clinical applications of PRR15 on TNBC. PRR15 gene was differentially expressed between TNBC and non-TNBC patients, previously described as an oncogenic factor in breast cancer. However, our results showed a decreased expression of PRR15 that portended a favorable prognosis in TNBC rather than non-TNBC. PRR15 knockdown facilitated the proliferation, migration, and invasive ability of TNBC cells in vitro and in vivo, which was abolished by PRR15 restoration, without remarkable effects on non-TNBC. High-throughput drug sensitivity revealed that PI3K/Akt signaling was involved in the aggressive properties of PRR15 silencing, which was confirmed by the PI3K/Akt signaling activation in the tumors of PRR15Low patients, and PI3K inhibitor reversed the metastatic capacity of TNBC in mice. The reduced PRR15 expression in TNBC patients was positively correlated with more aggressive clinicopathological characteristics, enhanced metastasis, and poor disease-free survival. Collectively, PRR15 down-regulation promotes malignant progression through the PI3K/Akt signaling in TNBC rather than in non-TNBC, affects the response of TNBC cells to antitumor agents, and is a promising indicator of disease outcomes in TNBC.

Loss of TTC17 promotes breast cancer metastasis through RAP1/CDC42 signaling and sensitizes it to rapamycin and paclitaxel.

BACKGROUND: Breast cancer (BC) metastasis is the leading cause of poor prognosis and therapeutic failure. However, the mechanisms underlying cancer metastasis are far from clear. METHODS: We screened candidate genes related to metastasis through genome-wide CRISPR screening and high-throughput sequencing of patients with metastatic BC, followed by a panel of metastatic model assays. The effects of tetratricopeptide repeat domain 17 (TTC17) on migration, invasion, and colony formation ability together with the responses to anticancer drugs were investigated in vitro and in vivo. The mechanism mediated by TTC17 was determined by RNA sequencing, Western blotting, immunohistochemistry, and immunofluorescence. The clinical significance of TTC17 was evaluated using BC tissue samples combined with clinicopathological data. RESULTS: We identified the loss of TTC17 as a metastasis driver in BC, and its expression was negatively correlated with malignancy and positively correlated with patient prognosis. TTC17 loss in BC cells promoted their migration, invasion, and colony formation capacity in vitro and lung metastasis in vivo. Conversely, overexpressing TTC17 suppressed these aggressive phenotypes. Mechanistically, TTC17 knockdown in BC cells resulted in the activation of the RAP1/CDC42 pathway along with a disordered cytoskeleton in BC cells, and pharmacological blockade of CDC42 abolished the potentiation of motility and invasiveness caused by TTC17 silencing. Research on BC specimens demonstrated reduced TTC17 and increased CDC42 in metastatic tumors and lymph nodes, and low TTC17 expression was linked to more aggressive clinicopathologic characteristics. Through screening the anticancer drug library, the CDC42 inhibitor rapamycin and the microtubule-stabilizing drug paclitaxel showed stronger inhibition of TTC17-silenced BC cells, which was confirmed by more favorable efficacy in BC patients and tumor-bearing mice receiving rapamycin or paclitaxel in the TTC17Low arm. CONCLUSIONS: TTC17 loss is a novel factor promoting BC metastasis, that enhances migration and invasion by activating RAP1/CDC42 signaling and sensitizes BC to rapamycin and paclitaxel, which may improve stratified treatment strategies under the concept of molecular phenotyping-based precision therapy of BC.

Expression dynamics of periodic transcripts during cancer cell cycle progression and their correlation with anticancer drug sensitivity.

BACKGROUND: The cell cycle is at the center of cellular activities and is orchestrated by complex regulatory mechanisms, among which transcriptional regulation is one of the most important components. Alternative splicing dramatically expands the regulatory network by producing transcript isoforms of genes to exquisitely control the cell cycle. However, the patterns of transcript isoform expression in the cell cycle are unclear. Therapies targeting cell cycle checkpoints are commonly used as anticancer therapies, but none of them have been designed or evaluated at the alternative splicing transcript level. The utility of these transcripts as markers of cell cycle-related drug sensitivity is still unknown, and studies on the expression patterns of cell cycle-targeting drug-related transcripts are also rare. METHODS: To explore alternative splicing patterns during cell cycle progression, we performed sequential transcriptomic assays following cell cycle synchronization in colon cancer HCT116 and breast cancer MDA-MB-231 cell lines, using flow cytometry and reference cell cycle transcripts to confirm the cell cycle phases of samples, and we developed a new algorithm to describe the periodic patterns of transcripts fluctuating during the cell cycle. Genomics of Drug Sensitivity in Cancer (GDSC) drug sensitivity datasets and Cancer Cell Line Encyclopedia (CCLE) transcript datasets were used to assess the correlation of genes and their transcript isoforms with drug sensitivity. We identified transcripts associated with typical drugs targeting cell cycle by determining correlation coefficients. Cytotoxicity assays were used to confirm the effect of ENST00000257904 against cyclin dependent kinase 4/6 (CDK4/6) inhibitors. Finally, alternative splicing transcripts associated with mitotic (M) phase arrest were analyzed using an RNA synthesis inhibition assay and transcriptome analysis. RESULTS: We established high-resolution transcriptome datasets of synchronized cell cycle samples from colon cancer HCT116 and breast cancer MDA-MB-231 cells. The results of the cell cycle assessment showed that 43,326, 41,578 and 29,244 transcripts were found to be periodically expressed in HeLa, HCT116 and MDA-MB-231 cells, respectively, among which 1280 transcripts showed this expression pattern in all three cancer cell lines. Drug sensitivity assessments showed that a large number of these transcripts displayed a higher correlation with drug sensitivity than their corresponding genes. Cell cycle-related drug screening showed that the level of the CDK4 transcript ENST00000547281 was more significantly associated with the resistance of cells to CDK4/6 inhibitors than the level of the CDK4 reference transcript ENST00000257904. The transcriptional inhibition assay following M phase arrest further confirmed the M-phase-specific expression of the splicing transcripts. Combined with the cell cycle-related drug screening, the results also showed that a set of periodic transcripts, for example, ENST00000314392 (a dolichyl-phosphate mannosyltransferase polypeptide 2 isoform transcript), was more associated with drug sensitivity than the levels of their corresponding gene transcripts. CONCLUSIONS: In summary, we identified a panel of cell cycle-related periodic transcripts and found that the levels of transcripts of drug target genes showed different values for predicting drug sensitivity, providing novel insights into alternative splicing-related drug development and evaluation.

Propane-Trapping Ultramicroporous Metal-Organic Framework in the Low-Pressure Area toward the Purification of Propylene.

The propane (C3H8)-trapping adsorption behavior is considered as a potential performance to directly produce high-purity propylene (C3H6). Herein, we report an ultramicroporous Mn-based metal-organic framework (NUM-7) with a reverse C3H8-selective behavior in the low-pressure area. The pore structure of this material possesses more electronegative aromatic benzene rings for the stronger binding affinity to C3H8, and the material shows outstanding reverse ideal adsorbed solution theory (IAST) selectivity values. Single-component sorption isotherms preliminarily show the reverse adsorption behavior in the low-pressure part, and the moderate heat of adsorption further confirms this performance and exhibits less energy consumption for regeneration. In addition, the purification effect for the C3H8/C3H6 mixture is evaluated by the IAST selectivity and transient breakthrough curves, and the GCMC calculation results reveal that the fascinating C3H8-trapping behavior mainly depends on the multiple C-H···π interactions. Moreover, because C3H6 is the desired target product, the interesting C3H8-selective adsorption behavior of NUM-7 may provide its potential for one-step purification of C3H6, and this work can provide the method of developing C3H8-selective materials for the purification of C3H6.

Comprehensive analysis reveals GRP94 is associated with worse prognosis of breast cancer.

BACKGROUND: Breast cancer (BC) is the most common cancer diagnosed in women around the world. Glucose-related protein 94 (GRP94) is a molecular chaperone on the endoplasmic reticulum (ER) that is associated with many malignancies, although its role in breast carcinogenesis has remained unclear. This study aimed to investigate the expression of GRP94 in BC and its relationship with BC clinicopathological features and prognosis based on a comprehensive analysis. METHODS: The mutation and expression patterns of GRP94 in multiple cancers were elucidated from TCGA data. A GRP94 IS (immune score) was generated from breast tumors in Chinese women by multiplying the staining intensity and the percentage of positive cells. The relationship between GRP94 expression and clinicopathological parameters in TMA samples was identified by Spearman correlation analysis. We established a GRP94 co-expression interaction network from two databases (TCGA and STRING). Overall survival (OS) and relapse-free survival (RFS) were determined via the KM-plotter analysis platform. RESULTS: GRP94 is mutated in most cancer types, and the average mutation frequency is 1.1%. GRP94 expression in BC was in the middle of the expression levels of the analyzed cancer types. The protein level of GRP94 was significantly higher in BC tissues than in normal breast tissues. A high level of GRP94 was positively associated with the levels of PR and AR and negatively associated with the level of EGFR but was not associated with age, pathological types, pathological grades, clinical stages or the levels of ER, HER2, P53, Ki67, or CK5/6. High expression of GRP94 predicted decreased OS and RFS in BC. The cluster analysis of the GRP94 gene coexpression network showed six dominant biological events, including ribosome biogenesis, amino acid activation, ER stress, protein folding and protein localization to the nucleus, cell cycle processes and ubiquitin-protein ligase activity involved in the mitotic cell cycle. CONCLUSIONS: The study suggests that GRP94 could be a potential prognostic factor in BC.

Efficient Purification of Ethylene from C2 Hydrocarbons with an C2H6/C2H2-Selective Metal-Organic Framework.

The separation of ethylene (C2H4) from C2 hydrocarbons is considered as one of the most difficult and important processes in the petrochemical industry. Heat-driven cryogenic distillation is still widely used in the C2 hydrocarbons separation realms, which is an energy intensive process and takes up immense space. In response to a greener, more energy-efficient sustainable development, we successfully synthesized a multifunction microporous Mg-based MOF [Mg2(TCPE)(µ2-OH2)(DMA)2]·solvents (NUM-9) with C2H6/C2H2 selectivity based on a physical adsorption mechanism, and with outstanding stability; especially, it is stable up to 500 °C under an air atmosphere. NUM-9a (activated NUM-9) shows good performances in the separation of C2H6/C2H2 from raw ethylene gases. In addition, its actual separation potential is also examined by IAST and dynamic column breakthrough experiments. GCMC calculation results indicate that the unique structure of NUM-9a is primarily conducive to the selective adsorption of C2H6 and C2H2. More importantly, compared with C2H4, NUM-9a prefers to selectively adsorb C2H6 and C2H2 simultaneously, which makes NUM-9a as a sorbent have the capacity to separate C2H4 from C2 hydrocarbon mixtures under mild conditions through a greener and energy-efficient separation strategy.

Microporous Metal-Organic Framework with a Completely Reversed Adsorption Relationship for C2 Hydrocarbons at Room Temperature.

As a new type of porous material, metal-organic frameworks (MOFs) have been widely studied in gas adsorption and separation, especially in C2 hydrocarbons. Considering the stronger interaction between the unsaturated molecules and the metal sites, and the smaller molecular size of unsaturated molecules, the usual relationship of affinities and adsorption capacities among C2 hydrocarbons in most common MOFs is C2H2 > C2H4 > C2H6. Herein, a unique microporous metal-organic framework, NUM-7a (activated NUM-7), with a completely reversed adsorption relationship for C2 hydrocarbons (C2H6 > C2H4 > C2H2) has been successfully synthesized, which breaks the traditional concept of the adsorption relationship of MOFs for C2 hydrocarbons. Based on this unique adsorption relationship, a green and simple one-step separation purification for a large amount of C2H4 can be expected to be achieved through the selective adsorption of C2H6. In addition, NUM-7a also shows good selectivities in C2H2/CO2 and CO2/CH4.

Aerobic Oxidation of 5-Hydroxymethylfurfural to 2,5-Furandicarboxylic Acid over Holey 2 D Mn2 O3 Nanoflakes from a Mn-based MOF.

The aerobic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA), a promising renewable monomer to produce bio-based polymers such as polyethylene furanoate (PEF), has recently emerged as the subject of increasing interest. Here, holey 2 D Mn2 O3 nanoflakes were obtained by a facile thermal treatment of a Mn-based metal-organic framework (MOF) precursor. The structural and morphological properties of the nanoflakes were characterized by powder XRD, FTIR, SEM and TEM to explore the formation process. It was inferred that the linker loss in the MOF precursor and the oxidation of the Mn cation induced by the heat-treatment in air were responsible for the formation of holey 2 D Mn2 O3 nanoflakes. The specific morphology and redox cycle of the Mn cation on the surface endowed the synthesized nanoflakes with promising performance on the selective oxidation. The obtained nanoflakes calcined at 400 °C (M400) afforded over 99.5 % yield of FDCA at complete conversion of HMF, which is superior to the catalytic activity of commercial Mn2 O3 and activated MnO2 . To our knowledge, Mn2 O3 exhibiting such a high performance on the aerobic oxidation of HMF to FDCA has not yet been reported. Based on the investigation of the experimental parameters, a plausible reaction mechanism was proposed.

Toxicological effects of 3-methyl-4-nitrophenol on mouse ovarian and testicular cell proliferation, apoptosis and oocyte maturation.

The aim of the present study was to reveal the effects of 3-methyl-4-nitrophenol (PNMC) on mouse gonadal cell proliferation and apoptosis. Immature female and male mice were intramuscularly injected with 100 mg/kg PNMC or vehicle every five days. One-month later, ovarian rather than testicular weights were significantly decreased. The positive terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labelling staining was enhanced in both testicular seminiferous epithelium and ovarian corpus luteum. Further study in ovaries showed that PNMC treatment increased the protein expressions of PCNA, p21 and p27, and decreased the expression of Cyclin D2. Whereas PNMC had no significantly influence on those protein expressions in testes. In addition, we demonstrated that 100 nM PNMC significantly suppressed mouse oocyte meiotic resumption and cumulus cell expansion in vitro. These findings suggest that the reproductive toxicities of PNMC involve affecting the processes of gonadal cell apoptosis and proliferation.