Hypoxic tumor-derived exosomal miR-4488 induces macrophage M2 polarization to promote liver metastasis of pancreatic neuroendocrine neoplasm through RTN3/FABP5 mediated fatty acid oxidation.

Tumor-associated macrophages (TAMs) represent a predominant cellular component within the tumor microenvironment (TME) of pancreatic neuroendocrine neoplasms (pNENs). There is a growing body of evidence highlighting the critical role of exosomes in facilitating communication between tumor cells and TAMs, thereby contributing to the establishment of the premetastatic niche. Nonetheless, the specific mechanisms through which exosomes derived from tumor cells influence macrophage polarization under hypoxic conditions in pNENs, and the manner in which these interactions support cancer metastasis, remain largely unexplored. Recognizing the capacity of exosomes to transfer miRNAs that can modify cellular behaviors, our research identified a significant overexpression of miR-4488 in exosomes derived from hypoxic pNEN cells. Furthermore, we observed that macrophages that absorbed circulating exosomal miR-4488 underwent M2-like polarization. Our investigations revealed that miR-4488 promotes M2-like polarization by directly targeting and suppressing RTN3 in macrophages. This suppression of RTN3 enhances fatty acid oxidation and activates the PI3K/AKT/mTOR signaling pathway through the interaction and downregulation of FABP5. Additionally, M2 polarized macrophages contribute to the formation of the premetastatic niche and advance pNENs metastasis by releasing MMP2, thereby establishing a positive feedback loop involving miR-4488, RTN3, FABP5, and MMP2 in pNEN cells. Together, these findings shed light on the role of exosomal miRNAs from hypoxic pNEN cells in mediating interactions between pNEN cells and intrahepatic macrophages, suggesting that miR-4488 holds potential as a valuable biomarker and therapeutic target for pNENs.

Identification and characterization of two P450 enzymes from Citrus sinensis involved in TMTT and DMNT biosyntheses and Asian citrus psyllid defense.

The homoterpenes (3E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) and (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene (TMTT) are the major herbivore-induced plant volatiles that help in defense directly by acting as repellants and indirectly by recruiting insects' natural enemies. In this study, DMNT and TMTT were confirmed to be emitted from citrus (Citrus sinensis) leaves infested with Asian citrus psyllid (Diaphorina citri Kuwayama; ACP), and two cytochrome P450 (CYP) genes (CsCYP82L1 and CsCYP82L2) were newly identified and characterized. Understanding the functions of these genes in citrus defense will help plan strategies to manage huanglongbing caused by Candidatus Liberibacter asiaticus (CLas) and spread by ACP. Quantitative real-time PCR (qPCR) analysis showed that CsCYP82L1 and CsCYP82L2 were significantly upregulated in citrus leaves after ACP infestation. Yeast recombinant expression and enzyme assays indicated that CsCYP82L1 and CsCYP82L2 convert (E)-nerolidol to DMNT and (E,E)-geranyllinalool to TMTT. However, citrus calluses stably overexpressing CsCYP82L1 generated only DMNT, whereas those overexpressing CsCYP82L2 produced DMNT and TMTT. Furthermore, ACPs preferred wild-type lemon (Citrus limon) over the CsCYP82L1-overexpressing line in dual-choice feeding assays and mineral oil over TMTT or DMNT in behavioral bioassays. Finally, yeast one-hybrid, electrophoretic mobility shift, and dual luciferase assays demonstrated that CsERF017, an AP2/ERF transcription factor, directly bound to the CCGAC motif and activated CsCYP82L1. Moreover, the transient overexpression of CsERF017 in lemon leaves upregulated CsCYP82L1 in the absence and presence of ACP infestation. These results provide novel insights into homoterpene biosynthesis in C. sinensis and demonstrate the effect of homoterpenes on ACP behavior, laying a foundation to genetically manipulate homoterpene biosynthesis for application in huanglongbing and ACP control.

Experimental study on the effect of Coumarone resin on the performance of SBS-modified asphalt.

An inexpensive and high-performing solid Coumarone resin was added to Styrene-butadiene-styrene (SBS) copolymer-modified asphalt to enhance its storage stability and road performance. To assess the effect of Coumarone resin dosage on the SBS-modified asphalt, a series of laboratory tests were conducted. The composite modified asphalt's segregation test was used to evaluate its storage stability, Dynamic Shear Rheometer (DSR) and Multiple Stress Creep Recovery (MSCR) tests were employed to investigate its high-temperature performance and permanent deformation resistance, and the Bending Beam Rheology (BBR) test was utilized to measure its low-temperature performance. Fluorescence microscopy was used to observe the composite modified asphalt's microstructure, and Fourier Transform Infrared Spectroscopy (FTIR) was conducted to study the changes in chemical structure during the modification process. The results showed that Coumarone resin can improve the compatibility of SBS and asphalt, improve the high-temperature performance and deformation resistance of SBS-modified asphalt, and adding an appropriate amount of Coumarone resin can help enhance the low-temperature cracking resistance of modified asphalt. The optimal dosage of Coumarone resin recommended for SBS-modified asphalt performance enhancement is 2% under the test conditions, as determined by comparing the test results of samples with various dosages.

The Potential Regulation of Working Anode for Long-Term Zero-Volt Storage at 37 °C in Li-Ion Batteries.

The advanced lithium-ion batteries that can tolerate zero-volt storage (ZVS) are in high demand for implantable medical devices and spacecraft. However, ZVS can raise the anode potential, leading to Cu current collector dissolution and solid-electrolyte interphase (SEI) degradation, especially at 37 °C. In this contribution, by quantitatively regulating the dosage of Li6CoO4 cathode additives, controllable potential of the working anode under abusive-discharge conditions is demonstrated. The addition of Li6CoO4 keeps zero-crossing potential (ZCP) and the potential of ZVS below 2.0 V (vs Li/Li+) for LiCoO2|mesocarbon microbead cells at 37 °C. The capacity retention ratio (CRR) increases from 69.1% and 35.9% to 98.6% and 90.8% after 10 and 20 days of ZVS, respectively. The Cu dissolution and SEI degradation are effectively suppressed, while the over-lithiated cathode exhibits high reversible capacity after ZVS. The limiting conditions of long-term ZVS are further explored and a corresponding guide map is designed. When quantitatively regulating ZCP and the potential in ZVS, Cu dissolution, SEI degradation, and irreversible conversion of the cathode constitute the limiting conditions. This contribution designs the most reasonable potential range for ZVS protection at 37 °C, and realizes the best CRR record through precise potential regulation for the first time.

FOXA2-initiated transcriptional activation of INHBA induced by methylmalonic acid promotes pancreatic neuroendocrine neoplasm progression.

Pancreatic neuroendocrine neoplasms (PanNENs) are a group of highly heterogeneous neoplasms originating from the endocrine islet cells of the pancreas with characteristic neuroendocrine differentiation, more than 60% of which represent metastases when diagnosis, causing major tumor-related death. Metabolic alterations have been recognized as one of the hallmarks of tumor metastasis, providing attractive therapeutic targets. However, little is known about the molecular mechanism of metabolic changes regulating PanNEN progression. In this study, we first identified methylmalonic acid (MMA) as an oncometabolite for PanNEN progression, based on serum metabolomics of metastatic PanNEN compared with non-metastatic PanNEN patients. One of the key findings was the potentially novel mechanism of epithelial-mesenchymal transition (EMT) triggered by MMA. Inhibin ßA (INHBA) was characterized as a key regulator of MMA-induced PanNEN progression according to transcriptomic analysis, which has been validated in vitro and in vivo. Mechanistically, INHBA was activated by FOXA2, a neuroendocrine (NE) specific transcription factor, which was initiated during MMA-induced progression. In addition, MMA-induced INHBA upregulation activated downstream MITF to regulate EMT-related genes in PanNEN cells. Collectively, these data suggest that activation of INHBA via FOXA2 promotes MITF-mediated EMT during MMA inducing PanNEN progression, which puts forward a novel therapeutic target for PanNENs.

Hypoxia upregulating ACSS2 enhances lipid metabolism reprogramming through HMGCS1 mediated PI3K/AKT/mTOR pathway to promote the progression of pancreatic neuroendocrine neoplasms.

BACKGROUND: Pancreatic neuroendocrine neoplasms (pNENs) are relatively rare. Hypoxia and lipid metabolism-related gene acetyl-CoA synthetase 2 (ACSS2) is involved in tumor progression, but its role in pNENs is not revealed. This study showed that hypoxia can upregulate ACSS2, which plays an important role in the occurrence and development of pNENs through lipid metabolism reprogramming. However, the precise role and mechanisms of ACSS2 in pNENs remain unknown. METHODS: mRNA and protein levels of ACSS2 and 3-hydroxy-3-methylglutaryl-CoA synthase1 (HMGCS1) were detected using quantitative real-time PCR (qRT-PCR) and Western blotting (WB). The effects of ACSS2 and HMGCS1 on cell proliferation were examined using CCK-8, colony formation assay and EdU assay, and their effects on cell migration and invasion were examined using transwell assay. The interaction between ACSS2 and HMGCS1 was verified by Co-immunoprecipitation (Co-IP) experiments, and the functions of ACSS2 and HMGCS1 in vivo were determined by nude mouse xenografts. RESULTS: We demonstrated that hypoxia can upregulate ACSS2 while hypoxia also promoted the progression of pNENs. ACSS2 was significantly upregulated in pNENs, and overexpression of ACSS2 promoted the progression of pNENs and knockdown of ACSS2 and ACSS2 inhibitor (ACSS2i) treatment inhibited the progression of pNENs. ACSS2 regulated lipid reprogramming and the PI3K/AKT/mTOR pathway in pNENs, and ACSS2 regulated lipid metabolism reprogramming through the PI3K/AKT/mTOR pathway. Co-IP experiments indicated that HMGCS1 interacted with ACSS2 in pNENs. Overexpression of HMGCS1 can reverse the enhanced lipid metabolism reprogramming and tumor-promoting effects of knockdown of ACSS2. Moreover, overexpression of HMGCS1 reversed the inhibitory effect of knockdown of ACSS2 on the PI3K/AKT/mTOR pathway. CONCLUSION: Our study revealed that hypoxia can upregulate the lipid metabolism-related gene ACSS2, which plays a tumorigenic effect by regulating lipid metabolism through activating the PI3K/AKT/mTOR pathway. In addition, HMGCS1 can reverse the oncogenic effects of ACSS2, providing a new option for therapeutic strategy.

High-quality genome assemblies for two Australimusa bananas (Musa spp.) and insights into regulatory mechanisms of superior fiber properties.

Bananas (Musa spp.) are monocotyledonous plants with high genetic diversity in the Musaceae family that are cultivated mainly in tropical and subtropical countries. The fruits are a popular food, and the plants themselves have diverse uses. Four genetic groups (genomes) are thought to have contributed to current banana cultivars: Musa acuminata (A genome), Musa balbisiana (B genome), Musa schizocarpa (S genome), and species of the Australimusa section (T genome). However, the T genome has not been effectively explored. Here, we present the high-quality TT genomes of two representative accessions, Abaca (Musa textilis), with high-quality natural fiber, and Utafun (Musa troglodytarum, Fe'i group), with abundant ß-carotene. Both the Abaca and Utafun assemblies comprise 10 pseudochromosomes, and their total genome sizes are 613 Mb and 619 Mb, respectively. Comparative genome analysis revealed that the larger size of the T genome is likely attributable to rapid expansion and slow removal of transposons. Compared with those of Musa AA or BB accessions or sisal (Agava sisalana), Abaca fibers exhibit superior mechanical properties, mainly because of their thicker cell walls with a higher content of cellulose, lignin, and hemicellulose. Expression of MusaCesA cellulose synthesis genes peaks earlier in Abaca than in AA or BB accessions during plant development, potentially leading to earlier cellulose accumulation during secondary cell wall formation. The Abaca-specific expressed gene MusaMYB26, which is directly regulated by MusaMYB61, may be an important regulator that promotes precocious expression of secondary cell wall MusaCesAs. Furthermore, MusaWRKY2 and MusaNAC68, which appear to be involved in regulating expression of MusaLAC and MusaCAD, may at least partially explain the high accumulation of lignin in Abaca. This work contributes to a better understanding of banana domestication and the diverse genetic resources in the Musaceae family, thus providing resources for Musa genetic improvement.

Two haplotype-resolved genome assemblies for AAB allotriploid bananas provide insights into banana subgenome asymmetric evolution and Fusarium wilt control.

Bananas (Musa spp.) are one of the world's most important fruit crops and play a vital role in food security for many developing countries. Most banana cultivars are triploids derived from inter- and intraspecific hybridizations between the wild diploid ancestor species Musa acuminate (AA) and M. balbisiana (BB). We report two haplotype-resolved genome assemblies of the representative AAB-cultivated types, Plantain and Silk, and precisely characterize ancestral contributions by examining ancestry mosaics across the genome. Widespread asymmetric evolution is observed in their subgenomes, which can be linked to frequent homologous exchange events. We reveal the genetic makeup of triploid banana cultivars and verify that subgenome B is a rich source of disease resistance genes. Only 58.5% and 59.4% of Plantain and Silk genes, respectively, are present in all three haplotypes, with >50% of genes being differentially expressed alleles in different subgenomes. We observed that the number of upregulated genes in Plantain is significantly higher than that in Silk at one-week post-inoculation with Fusarium wilt tropical race 4 (Foc TR4), which confirms that Plantain can initiate defense responses faster than Silk. Additionally, we compared genomic and transcriptomic differences among the genes related to carotenoid synthesis and starch metabolism between Plantain and Silk. Our study provides resources for better understanding the genomic architecture of cultivated bananas and has important implications for Musa genetics and breeding.

Chronic Sacral Nerve Stimulation Inhibits Visceral Hypersensitivity in Diarrhea-Predominant Irritable Bowel Syndrome Rats Model.

OBJECTIVE: Sacral nerve stimulation (SNS) is emerging as a novel treatment for irritable bowel syndrome (IBS). However, its effects are limited, and the underlying mechanisms remain largely unknown. MATERIALS AND METHODS: In this study, rats were divided into three groups (n = 12 rats per group): 1) the SNS group; 2) the sham SNS group (the sham group for short); and 3) the control group. The SNS and sham groups were exposed to chronic and acute stress to establish an IBS model. Electrode implantation surgery was performed in rats with the IBS model. The SNS group received electrical stimulation for 30 minutes every day for seven days. Abdominal withdrawal reflex (AWR) was used to evaluate the effect of SNS on visceral sensitivity in diarrhea-predominant IBS (IBS-D) rats. The frequency domain of heart rate variability (HRV) was analyzed to assess the effect of SNS on regulating the autonomic function. The expression of transient receptor potential vanilloid 1 (TRPV1) in the colon, spinal cord, and hippocampus was detected by immunohistochemistry to explore the mechanism of SNS in IBS-D rats. RESULTS: Compared with the sham group, AWR scores were significantly decreased under different gas volumes of stimulation of 0.4, 0.6, and 0.8 ml for rectal distention in the SNS group (all p < 0.05). However, there was no significant difference <1.0 ml between the two groups (p > 0.05). Compared with the sham group, the frequency domain indexes of HRV were significantly altered. Normalized low-frequency power and low frequency-to-high frequency ratio were significantly decreased, and normalized high-frequency power was significantly increased in the SNS group (all p < 0.05). Moreover, the expression of TRPV1 in the spinal cord and colon in the SNS group was significantly decreased compared with the sham group (both p < 0.05). These results suggested that chronic SNS not only improved the visceral sensitivity and autonomic dysfunction but also decreased the expression of TRPV1 in the spinal cord-gut tissue in IBS-D rats. CONCLUSION: Chronic SNS was found to have an inhibitory effect on visceral hypersensitivity in IBS-D rats, providing experimental evidence for its potential clinical application in IBS.

Frictional Wear and Thermal Fatigue Properties of Die Steel after Ultrasound-Assisted Alloying.

The surface layer of 8407 die steel was strengthened using the combination of ultrasonic surface rolling and high-energy ion implanting in the present work. The strengthened layer was then characterized via microstructure observation, composition analysis, and hardness test. After that, the frictional wear and thermal fatigue properties of high-energy ion implanting specimens and composite-reinforced specimens were compared. Results show that the pretreatment of specimens with ultrasonic surface rolling causes grain refinement in the material surface, which promotes the strengthening effect of high-energy ion implanting. The wear volume of composite-reinforced specimens at medium and high frequencies is reduced by about 20%, and the wear resistance of these specimens is significantly improved with a lower friction coefficient and wear volume at moderate and high frequencies in alternating load friction experiments. Meanwhile, the thermal fatigue crack depth of composite-reinforced specimens is reduced by about 47.5%, which effectively prevents the growth of thermal cracks in the surface, thus improving the curing ability of the implanted elements. Therefore, composite strengthening of the mold steel surface is conducive to improving the cycle life, ensuring accuracy, effectively hindering the expansion of thermal cracks, and saving the cost of production.

ALKBH5 enhances lipid metabolism reprogramming by increasing stability of FABP5 to promote pancreatic neuroendocrine neoplasms progression in an m6A-IGF2BP2-dependent manner.

The process of post-transcriptional regulation has been recognized to be significantly impacted by the presence of N6-methyladenosine (m6A) modification. As an m6A demethylase, ALKBH5 has been shown to contribute to the progression of different cancers by increasing expression of several oncogenes. Hence, a better understanding of the key targets of ALKBH5 in cancer cells could potentially lead to the development of new therapeutic targets. However, the specific role of ALKBH5 in pancreatic neuroendocrine neoplasms (pNENs) remains largely unknown. Here, we demonstrated that ALKBH5 was up-regulated in pNENs and played a critical role in tumor growth and lipid metabolism. Mechanistically, ALKBH5 over-expression was found to increase the expression of FABP5 in an m6A-IGF2BP2 dependent manner, leading to disorders in lipid metabolism. Additionally, ALKBH5 was found to activate PI3K/Akt/mTOR signaling pathway, resulting in enhanced lipid metabolism and proliferation abilities. In conclusion, our study uncovers the ALKBH5/IGF2BP2/FABP5/mTOR axis as a mechanism for aberrant m6A modification in lipid metabolism and highlights a new molecular basis for the development of therapeutic strategies for pNENs treatment.

Bent and Twisted: Synthesis of an Alkoxy-Substituted (1,5)Naphthalene-paracyclophanediene.

This contribution describes the synthesis of [2.2](1,5)naphthalenoparacyclophane-1,13-diene in four steps from 1,5-bis(bromomethyl)naphthalene and 1,4-benzenedimethanethiol. Consisting of 2,6-dioctyloxynaphthalene and benzene moieties, the effects of differing arene size on the structure, strain energy, and chemical reactivity of the cyclophanediene are examined. Despite a strain energy of 24.3 kcal/mol, the naphthalenoparacyclophanediene was unreactive toward a library of olefin metathesis catalysts. This diminished reactivity can be explained by the steric hindrance of the twisted olefin. Incorporation of an electron donor (naphthalene) into the rigid paracyclophanediene structure can allow for applications in optoelectronics, chiral ligands, and planar chiral materials.

Down-regulated FTO and ALKBH5 co-operatively activates FOXO signaling through m6A methylation modification in HK2 mRNA mediated by IGF2BP2 to enhance glycolysis in colorectal cancer.

BACKGROUND: N6-methyladenosine (m6A) modification is the most abundant reversible methylation modification in eukaryotes, and it is reportedly closely associated with a variety of cancers progression, including colorectal cancer (CRC). This study showed that activated lipid metabolism and glycolysis play vital roles in the occurrence and development of CRC. However, only a few studies have reported the biological mechanisms underlying this connection. METHODS: Protein and mRNA levels of FTO and ALKBH5 were measured using western blot and qRT-PCR. The effects of FTO and ALKBH5 on cell proliferation were examined using CCK-8, colony formation, and EdU assays, and the effects on cell migration and invasion were tested using a transwell assay. m6A RNA immunoprecipitation (MeRIP) and RNA-seq was used to explore downstream target gene. RIP was performed to verify the interaction between m6A and HK2. The function of FTO and ALKBH5 in vivo was determined by xenograft in nude mice. RESULTS: In this study, FTO and ALKBH5 were significantly down-regulated in CRC patients and cells both in vivo and in vitro in a high-fat environment. Moreover, FTO and ALKBH5 over-expression hampered cell proliferation both in vitro and in vivo. Conversely, FTO and ALKBH5 knockdown accelerated the malignant biological behaviors of CRC cells. The mechanism of action of FTO and ALKBH5 involves joint regulation of HK2, a key enzyme in glycolysis, which was identified by RNA sequencing and MeRIP-seq. Furthermore, reduced expression of FTO and ALKBH5 jointly activated the FOXO signaling pathway, which led to enhanced proliferation ability in CRC cells. IGF2BP2, as a m6A reader, positively regulated HK2 mRNA in m6A dependent manner. Additionally, down-regulation of FTO/ALKBH5 increased METTL3 and decreased METTL14 levels, further promoting CRC progression. CONCLUSION: In conclusion, our study revealed the FTO-ALKBH5/IGF2BP2/HK2/FOXO1 axis as a mechanism of aberrant m6A modification and glycolysis regulation in CRC.

WTAP activates MAPK signaling through m6A methylation in VEGFA mRNA-mediated by YTHDC1 to promote colorectal cancer development.

N6-methyladenosine modification, especially Wilms tumor 1-associated protein (WTAP), is reportedly associated with a variety of cancers, including colorectal cancer (CRC). Angiogenesis also plays an important role in the occurrence and development of CRC. However, only a few studies have reported the biological mechanisms underlying this connection. Therefore, tissue microarray and public database were used to explore WTAP levels in CRC. Then, WTAP was down-regulated and over-expressed, respectively. CCK8, EdU, colony formation, and transwell experiments were performed to study the role of WTAP in CRC. Combined RNA sequencing and m6A RNA immunoprecipitation (MeRIP) sequencing, we found downstream molecules VEGFA. Moreover, a tube formation assay was executed for tumor angiogenesis. Finally, a subcutaneous tumorigenesis assay in nude mice was used to examine the tumor-promoting effect of WTAP in vivo. In the present study, WTAP was significantly upregulated in CRC cells and patients with CRC. Moreover, higher WTAP expression was observed in the TCGA and CPATC databases in CRC tissues. WTAP over-expression exacerbates cell proliferation, migration, invasion, and angiogenesis. Conversely, WTAP knockdown inhibited the malignant biological behavior of CRC cells. Mechanistically, WTAP positively regulated VEGFA, as identified using RNA sequencing and MeRIP sequencing. Moreover, we identified YTHDC1 as a downstream effector of the YTHDC1-VEGFA axis in CRC. Furthermore, increased WTAP expression activated the MAPK signaling pathway, which led to enhanced angiogenesis. In conclusion, our study revealed that the WTAP/YTHDC1/VEGFA axis promotes CRC development, especially angiogenesis, suggesting that it may act as a potential biomarker of CRC.

Methylmalonic acid promotes colorectal cancer progression via activation of Wnt/ß-catenin pathway mediated epithelial-mesenchymal transition.

BACKGROUND: It has been manifested in several studies that age-related metabolic reprogramming is associated with tumor progression, in particular, colorectal cancer (CRC). Here we investigated the role of upregulated metabolites of the aged serum, including methylmalonic acid (MMA), phosphoenolpyruvate (PEP), and quinolinate (QA), in CRC. METHODS: Functional assays including CCK-8, EdU, colony formation and transwell experiments were used to ascertain which upregulated metabolite of elderly serum was related to tumor progression. RNA-seq analysis was conducted to explore the potential mechanisms of MMA-induced CRC progression. Subcutaneous tumorigenesis and metastatic tumor models were constructed to verify the function of MMA in vivo. RESULTS: Among three consistently increased metabolites of the aged sera, MMA was responsible for tumorigenesis and metastasis in CRC, according to functional assays. The promotion of Epithelial-mesenchymal transition (EMT) was observed in CRC cells treated with MMA, on the basis of protein expression of EMT markers. Moreover, combined with transcriptome sequencing, Wnt/ß-catenin signaling pathway was activated in CRC cells treated with MMA, which was verified by western blot and qPCR experiments. Furthermore, animal assays demonstrated the pro-proliferation and promotion of metastasis role of MMA in vivo. CONCLUSION: We have identified that age-dependent upregulation of MMA in serum promoted the progression of CRC via Wnt/ß-catenin signaling pathway mediated EMT. These collective findings provide valuable insights into the vital role of age-related metabolic reprogramming in CRC progression and propose a potential therapeutic target for elderly CRC.

FABP5 suppresses colorectal cancer progression via mTOR-mediated autophagy by decreasing FASN expression.

Lipid metabolism plays an important role in the occurrence and development of cancer, in particular, digestive system tumors such as colon cancer. Here, we investigated the role of the fatty acid-binding protein 5 (FABP5) in colorectal cancer (CRC). We observed marked down-regulation of FABP5 in CRC. Data from functional assays revealed inhibitory effects of FABP5 on cell proliferation, colony formation, migration, invasion as well as tumor growth in vivo. In terms of mechanistic insights, FABP5 interacted with fatty acid synthase (FASN) and activated the ubiquitin proteasome pathway, leading to a decrease in FASN expression and lipid accumulation, moreover, suppressing mTOR signaling and facilitating cell autophagy. Orlistat, a FASN inhibitor, exerted anti-cancer effects both in vivo and in vitro. Furthermore, the upstream RNA demethylase ALKBH5 positively regulated FABP5 expression via an m6A-independent mechanism. Overall, our collective findings offer valuable insights into the critical role of the ALKBH5/FABP5/FASN/mTOR axis in tumor progression and uncover a potential mechanism linking lipid metabolism to development of CRC, providing novel therapeutic targets for future interventions.

Orlistat Induces Ferroptosis in Pancreatic Neuroendocrine Tumors by Inactivating the MAPK Pathway.

Background: Orlistat is an antiobesity drug approved by the US Food and Drug Administration (FDA) with potential antitumor activity against a few malignant tumors, however, whether orlistat affects the progression of pancreatic neuroendocrine tumors (pNETs) remains unknown. Methods: Protein and mRNA levels of FASN were measured using western blotting (WB) and qRT-PCR. The effects of FASN and orlistat on cell proliferation were examined using CCK-8, colony formation, and EdU assays. The effects of FASN and orlistat on cell migration and invasion were tested using a transwell assay. A lipid peroxidation assay was used to explore the effects of orlistat on ferroptosis. The function of orlistat in vivo was determined by xenograft in nude mice. Results: Based on the results of WB and qRT-PCR, FASN was significantly up-regulated in pNET cell lines and public database indicated increased expression of FASN correlated with poor prognosis for patients with pNET. CCK-8, colony formation, and EdU assays showed that knockdown of FASN or treatment with orlistat suppressed the proliferation of pNET cells. The transwell assay indicated that the knockdown of FASN or treatment with orlistat inhibited the migration and invasion of pNET cells. WB and the peroxidation assay showed that orlistat induced ferroptosis in pNET cells. Moreover, orlistat was also found to inhibit the MAPK pathway in pNETs. Furthermore, orlistat showed excellent anti-tumor effects in xenografts in nude mice. Conclusion: Altogether, our study demonstrates that orlistat inhibits the progression of pNETs by inducing ferroptosis mediated by inactivation of the MAPK signaling pathway. Therefore, orlistat is a promising candidate for the treatment of pNETs.

FABP5 regulates lipid metabolism to facilitate pancreatic neuroendocrine neoplasms progression via FASN mediated Wnt/ß-catenin pathway.

Pancreatic neuroendocrine neoplasms (pNENs) are among the most frequently occurring neuroendocrine neoplasms (NENs) and require targeted therapy. High levels of fatty acid binding protein 5 (FABP5) are involved in tumor progression, but its role in pNENs remains unclear. We investigated the mRNA and protein levels of FABP5 in pNEN tissues and cell lines and found them to be upregulated. We evaluated changes in cell proliferation using CCK-8, colony formation, and 5-ethynyl-2'-deoxyuridine assays and examined the effects on cell migration and invasion using transwell assays. We found that knockdown of FABP5 suppressed the proliferation, migration, and invasion of pNEN cell lines, while overexpression of FABP5 had the opposite effect. Co-immunoprecipitation experiments were performed to clarify the interaction between FABP5 and fatty acid synthase (FASN). We further showed that FABP5 regulates the expression of FASN via the ubiquitin proteasome pathway and both proteins facilitate the progression of pNENs. Our study demonstrated that FABP5 acts as an oncogene by promoting lipid droplet deposition and activating the WNT/ß-catenin signaling pathway. Moreover, the carcinogenic effects of FABP5 can be reversed by orlistat, providing a novel therapeutic intervention option.

Insecticidal and Repellent Properties of Rapid-Acting Fluorine-Containing Compounds against Aedes aegypti Mosquitoes.

The development of safe and potent insecticides remains an integral part of a multifaceted strategy to effectively control human-disease-transmitting insect vectors. Incorporating fluorine can dramatically alter the physiochemical properties and bioavailability of insecticides. For example, 1,1,1-trichloro-2,2-bis(4-fluorophenyl)ethane (DFDT)─a difluoro congener of trichloro-2,2-bis(4-chlorophenyl)ethane (DDT)─was demonstrated previously to be 10-fold less toxic to mosquitoes than DDT in terms of LD50 values, but it exhibited a 4-fold faster knockdown. Described herein is the discovery of fluorine-containing 1-aryl-2,2,2-trichloro-ethan-1-ols (FTEs, for fluorophenyl-trichloromethyl-ethanols). FTEs, particularly per-fluorophenyl-trichloromethyl-ethanol (PFTE), exhibited rapid knockdown not only against Drosophila melanogaster but also against susceptible and resistant Aedes aegypti mosquitoes, major vectors of Dengue, Zika, yellow fever, and Chikungunya viruses. The R enantiomer of any chiral FTE, synthesized enantioselectively, exhibited faster knockdown than its corresponding S enantiomer. PFTE does not prolong the opening of mosquito sodium channels that are characteristic of the action of DDT and pyrethroid insecticides. In addition, pyrethroid/DDT-resistant Ae. aegypti strains having enhanced P450-mediated detoxification and/or carrying sodium channel mutations that confer knockdown resistance were not cross-resistant to PFTE. These results indicate a mechanism of PFTE insecticidal action distinct from that of pyrethroids or DDT. Furthermore, PFTE elicited spatial repellency at concentrations as low as 10 ppm in a hand-in-cage assay. PFTE and MFTE were found to possess low mammalian toxicity. These results suggest the substantial potential of FTEs as a new class of compounds for controlling insect vectors, including pyrethroid/DDT-resistant mosquitoes. Further investigations of FTE insecticidal and repellency mechanisms could provide important insights into how incorporation of fluorine influences the rapid lethality and mosquito sensing.