SF3B3-regulated mTOR alternative splicing promotes colorectal cancer progression and metastasis.

BACKGROUND: Aberrant alternative splicing (AS) is a pervasive event during colorectal cancer (CRC) development. SF3B3 is a splicing factor component of U2 small nuclear ribonucleoproteins which are crucial for early stages of spliceosome assembly. The role of SF3B3 in CRC remains unknown. METHODS: SF3B3 expression in human CRCs was analyzed using publicly available CRC datasets, immunohistochemistry, qRT-PCR, and western blot. RNA-seq, RNA immunoprecipitation, and lipidomics were performed in SF3B3 knockdown or overexpressing CRC cell lines. CRC cell xenografts, patient-derived xenografts, patient-derived organoids, and orthotopic metastasis mouse models were utilized to determine the in vivo role of SF3B3 in CRC progression and metastasis. RESULTS: SF3B3 was upregulated in CRC samples and associated with poor survival. Inhibition of SF3B3 by RNA silencing suppressed the proliferation and metastasis of CRC cells in vitro and in vivo, characterized by mitochondria injury, increased reactive oxygen species (ROS), and apoptosis. Mechanistically, silencing of SF3B3 increased mTOR exon-skipped splicing, leading to the suppression of lipogenesis via mTOR-SREBF1-FASN signaling. The combination of SF3B3 shRNAs and mTOR inhibitors showed synergistic antitumor activity in patient-derived CRC organoids and xenografts. Importantly, we identified SF3B3 as a critical regulator of mTOR splicing and autophagy in multiple cancers. CONCLUSIONS: Our findings revealed that SF3B3 promoted CRC progression and metastasis by regulating mTOR alternative splicing and SREBF1-FASN-mediated lipogenesis, providing strong evidence to support SF3B3 as a druggable target for CRC therapy.

Targeting FTO induces colorectal cancer ferroptotic cell death by decreasing SLC7A11/GPX4 expression.

Ferroptosis is a newly identified iron-dependent form of death that is becoming increasingly recognized as a promising avenue for cancer therapy. N6-methyladenosine (m6A) is the most abundant reversible methylation modification in mRNA contributing to tumorigenesis. However, the crucial role of m6A modification in regulating ferroptosis during colorectal cancer (CRC) tumorigenesis remains elusive. Herein, we find that m6A modification is increased during ferroptotic cell death and correlates with the decreased m6A demethylase fat mass and obesity-associated protein (FTO) expression. Functionally, we demonstrate that suppressing FTO significantly induces CRC ferroptotic cell death, as well as enhancing CRC cell sensitivity to ferroptosis inducer (Erastin and RSL3) treatment. Mechanistically, high FTO expression increased solute carrier family 7 member 11 (SLC7A11) or glutathione peroxidase 4 (GPX4) expressions in an m6A-YTHDF2 dependent manner, thereby counteracting ferroptotic cell death stress. In addition, we identify Mupirocin as a novel inhibitor of FTO, and Mupirocin induces CRC ferroptosis and inhibits tumor growth. Clinically, the levels of FTO, SLC7A11, and GPX4, are highly correlated expression in CRC tissues. Our findings reveal that FTO protects CRC from ferroptotic cell death in promoting CRC tumorigenesis through triggering SLC7A11/GPX4 expression.

Discovery of a nitroaromatic nannocystin with potent in vivo anticancer activity against colorectal cancer by targeting AKT1.

The development of targeted chemotherapeutic agents against colorectal cancer (CRC), one of the most common cancers with a high mortality rate, is in a constant need. Nannocystins are a family of myxobacterial secondary metabolites featuring a 21-membered depsipeptide ring. The in vitro anti-CRC activity of natural and synthetic nannocystins was well documented, but little is known about their in vivo efficacy and if positive, the underlying mechanism of action. In this study we synthesized a nitroaromatic nannocystin through improved preparation of a key fragment, and characterized its in vitro activity and in vivo efficacy against CRC. We first described the total synthesis of compounds 2-4 featuring Heck macrocyclization to forge their 21-membered macrocycle. In a panel of 7 cancer cell lines from different tissues, compound 4 inhibited the cell viability with IC values of 1-6 nM. In particular, compound 4 (1, 2, 4 nM) inhibited the proliferation of CRC cell lines (HCT8, HCT116 and LoVo) in both concentration and time dependent manners. Furthermore, compound 4 concentration-dependently inhibited the colony formation and migration of CRC cell lines. Moreover, compound 4 induced cell cycle arrest at sub-G1 phase, apoptosis and cellular senescence in CRC cell lines. In three patient-derived CRC organoids, compound 4 inhibited the PDO with IC values of 3.68, 28.93 and 11.81 nM, respectively. In a patient-derived xenograft mouse model, injection of compound 4 (4, 8 mg/kg, i.p.) every other day for 12 times dose-dependently inhibited the tumor growth without significant change in body weight. We conducted RNA-sequencing, molecular docking and cellular thermal shift assay to elucidate the anti-CRC mechanisms of compound 4, and revealed that it exerted its anti-CRC effect at least in part by targeting AKT1.

Microbiota-derived imidazole propionate inhibits type 2 diabetic skin wound healing by targeting SPNS2-mediated S1P transport.

Imidazole propionate (ImP) is a recently discovered metabolite of T2DM-related gut microbiota. The effect of ImP on T2DM wound healing has not been studied yet. In this research, the changes of ImP-producing bacteria on the skin are firstly evaluated. 16sRNA sequencing results showed that the abundance of ImP-producing bacteria-Streptococcus in the intestine and skin of T2DM mice is significantly increased. Animal experiments show that ImP can inhibit the process of wound healing and inhibit the formation of blood vessels in the process of wound healing. Molecular mechanism research results show that ImP can inhibit S1P secretion mediated by SPNS2, and inhibit the activation of Rho signaling pathway, thereby affecting the angiogenesis process of HUVEC cells. This work also provides a potential drug HMPA that promotes T2DM wound healing.

Tyrosine metabolic reprogramming coordinated with the tricarboxylic acid cycle to drive glioma immune evasion by regulating PD-L1 expression.

Due to the existence of the blood-brain barrier in glioma, traditional drug therapy has a poor therapeutic outcome. Emerging immunotherapy has been shown to have satisfactory therapeutic effects in solid tumors, and it is clinically instructive to explore the possibility of immunotherapy in glioma. We performed a retrospective analysis of RNA-seq data and clinical information in 1027 glioma patients, utilizing machine learning to explore the relationship between tyrosine metabolizing enzymes and clinical characteristics. In addition, we also assessed the role of tyrosine metabolizing enzymes in the immune microenvironment including immune infiltration and immune evasion. Highly expressed tyrosine metabolizing enzymes 4-hydroxyphenylpyruvate dioxygenase, homogentisate 1,2-dioxygenase, and fumarylacetoacetate hydrolase not only promote the malignant phenotype of glioma but are also closely related to poor prognosis. The expression of tyrosine metabolizing enzymes could distinguish the malignancy degree of glioma. More importantly, tyrosine metabolizing enzymes regulate the adaptive immune process in glioma. Mechanistically, multiple metabolic enzymes remodel fumarate metabolism, promote α-ketoglutarate production, induce programmed death-ligand 1 expression, and help glioma evade immune surveillance. Our data suggest that the metabolic subclass driven by tyrosine metabolism provides promising targets for the immunotherapy of glioma.

A model for identification of potential phase-separated proteins based on protein sequence, structure and cellular distribution.

The cells are like a highly industrialized and urbanized city, filled with numerous biological macromolecules and metabolites, forming a crowded environment. While, the cells have compartmentalized organelles to complete different biological processes efficiently and orderly. However, membraneless organelles are more dynamic and adaptable for transient events including signal transduction and molecular interactions. Liquid-liquid phase separation (LLPS) is a mechanism that is widespread in which macromolecules form condensates without membranes to exert biological functions in crowded environments. Due to the lack of deep understanding of phase-separated proteins, platforms exploring phase-separated proteins by high-throughput methods is lacking. Bioinformatics has its unique properties and has proven to be a great impetus in multiple fields. Here, We integrated the amino acid sequence, protein structure, and cellular localization, then developed a workflow for screening phase-separated proteins and identified a novel cell cycle-related phase separation protein, serine/arginine-rich splicing factor 2 (SRSF2). In conclusion, we developed a workflow as a useful resource for predicting phase-separated proteins based on multi-prediction tool, which has an important contribution to the further identification of phase-separated proteins and the development strategies for treating disease.

Exosome-like nanovesicles derived from Phellinus linteus inhibit Mical2 expression through cross-kingdom regulation and inhibit ultraviolet-induced skin aging.

BACKGROUND: Phellinus linteus (PL), which is a typical medicinal fungus, has been shown to have antitumor and anti-inflammatory activities. However, studies on the effect of anti-photoaging are limited. Studies have shown that exosome-like nanovesicles are functional components of many medicinal plants, and miRNAs in exosome-like nanovesicles play a cross-kingdom regulatory role. At present, research on fungi exosome-like nanovesicles (FELNVs) is few. RESULTS: We systematically evaluated the anti-aging effects of PL. FELNVs of PL were isolated, and the functional molecular mechanisms were evaluated. The results of volunteer testing showed that PL had anti-aging activity. The results of component analysis showed that FELNVs were the important components of PL function. FELNVs are nanoparticles (100-260 nm) with a double shell structure. Molecular mechanism research results showed that miR-CM1 in FELNVs could inhibit Mical2 expression in HaCaT cells through cross-kingdom regulation, thereby promoting COL1A2 expression; inhibiting MMP1 expression in skin cells; decreasing the levels of ROS, MDA, and SA-ß-Gal; and increasing SOD activity induced by ultraviolet (UV) rays. The above results indicated that miR-CM1 derived from PL inhibited the expression of Mical2 through cross-kingdom regulation and inhibited UV-induced skin aging. CONCLUSION: miR-CM1 plays an anti-aging role by inhibiting the expression of Mical2 in human skin cells through cross-species regulation.

Predictors and prognosis of PCI-related myocardial injury in chronic total occlusion.

BACKGROUND: Periprocedural myocardial injury (PMI) is associated with major adverse cardiovascular events (MACE) after percutaneous coronary intervention (PCI). However, the incidence predictors and prognosis of PMI in chronic total occlusion (CTO) undergoing PCI remains unclear. METHOD: To evaluate the predictors and prognostic impact of PMI following PCI in patients with CTO. We consecutively enrolled 132 individuals and 8 of whom with procedural failure were excluded in this study. Thus, a total of 124 CTO patients successfully received PCI were included in this study. And patients were divided into the PMI group (n = 42) and the non-PMI group (n = 82) according to their c-TnI levels measured after procedure. The baseline and angiographic characteristics of the two groups were compared. The predictors of PMI and the correlation between PMI and MACE were investigated. RESULTS: Overall, PMI occurred in 42 patients (33.9%). Comparing with control group, PMI group had more diabetes (54.8% vs. 31.7%,P = 0.013) and dyslipidemia (54.8% vs. 13.4%, P＜0.001). Also, there were significant differences between the two groups in left ventricular ejection fraction(43.2 ± 7.2 vs 47.2 ± 8.0, P = 0.027), prior myocardial infarction(54.8%vs43.1%, P = 0.020), prior PCI(57.1% vs 22.0%, P＜0.001) and prior CABG(14.3% vs 2.4%, P = 0.011). Also, patients with PMI had more calcified lesions (52.4% vs 24.4%, P = 0.002) and were more likely to have multivessel disease (71.4% vs 35.4%, P＜0.001). In addition, patients in the PMI group had higher J-CTO scores (3.3 ± 1.0 vs 1.9 ± 0.5, P＜0.001) and were more likely to have wire-crossing difficulties (64.3% vs 37.8%, P = 0.005), require more use of retrograde approach (38.1% vs 7.3%, P＜0.001) and have more procedural complications (19.0% vs 2.4%, P = 0.003). In the multivariate analysis, multivessel artery disease (odd ratio [OR], 4.347;95% confidence interval [CI], 1.601- 11.809;P = 0.004), retrograde approach (OR, 4.036; 95%CI, 1.162- 14.020;P = 0.028) and the presence of procedural complications (OR, 16.480;95%CI, 2.515-107.987;P = 0.003) were predictors of PMI. CONCLUSION: The incidence of PMI in CTO patients after PCI was 33.9%. Multivessel artery disease, retrograde approach, and the presence of procedural complications were predictors of PMI after CTO-PCI. Patients who develop PMI tend to have a poorer clinical prognosis and more MACE than those who do not develop PMI.

Relationship between increased systemic immune-inflammation index and coronary slow flow phenomenon.

BACKGROUND: Systemic immune-inflammation index (SII, platelet × neutrophil/lymphocyte ratio), a new marker of inflammation, is associated with adverse cardiovascular events, but its relationship with coronary slow flow phenomenon (CSFP) is unclear. Therefore, we aimed to investigate the relationship between SII and CSFP. METHODS: We enrolled consecutive patients who presented with chest pain, with normal/near-normal coronary angiography findings (n = 89 as CSFP group; n = 167 as control group). The baseline characteristics, laboratory parameters and angiographic characteristics of the two groups were compared. RESULTS: SII levels were significantly higher in the CSFP group than in the control group (409.7 ± 17.7 vs. 396.7 ± 12.7, p < 0.001). A significant positive correlation between SII and the mean thrombolysis in myocardial infarction frame count (mTFC) was found (r = 0.624, p < 0.001). SII increased with the number of coronary arteries involved in CSFP. In multivariate logistic regression analysis, SII/10 was an independent predictor of CSFP (odds ratio: 1.739, p < 0.001). In addition, the SII level > 404.29 was a predictor of CSFP with 67.4% sensitivity and 71.9% specificity. CONCLUSIONS: SII can predict the occurrence of CSFP.

A non-retinol retinoic acid receptor-γ (RAR-γ/NR1B3) selective agonist, tectorigenin, can effectively inhibit the ultraviolet A-induced skin damage.

BACKGROUND AND PURPOSE: Long-term ultraviolet (UV) exposure can cause inflammation, pigmentation and photoaging. All-trans retinoic acid (ATRA/tretinoin) is a commonly used retinoic acid receptor (RAR) agonist in the clinical treatment of UV-induced skin problems. However, the use of such drugs is often accompanied by systemic adverse reactions caused by nonspecific activation of RARs. Therefore, this study was designed to screen for a novel RAR-γ-selective agonist with high safety. EXPERIMENTAL APPROACH: Molecular docking, dynamic simulation and Biacore were used to screen and identify novel RAR-γ-selective agonists. RT-PCR, ELISA, western blotting, immunofluorescence staining, flow cytometry and proteomic analysis were used to detect the effects of these novel RAR-γ selective agonists on UVA-induced inflammation and photoaging cell models. UVA-induced mouse models were used to evaluate the effects of tectorigenin on skin repair, ageing and inflammation. KEY RESULTS: Tectorigenin is a novel RAR-γ-selective agonist, which inhibits UV-induced oxidative damage, inflammatory factor release and matrix metalloproteinase (MMP) production. Tectorigenin can also reverse the UVA-induced loss of collagen. The results of the signalling pathway research showed that tectorigenin mainly affects the MAPK/JNK/AP-1 pathway. In animal experiments, tectorigenin showed better anti-inflammatory and anti-photoaging effects, and caused less skin irritation than ATRA. Nano-particle loaded tectorigenin significantly improved the utilization of tectorigenin. CONCLUSIONS AND IMPLICATIONS: Tectorignen is a non-retinol RAR-γ-selective agonist that can inhibit UV-induced skin damage and could be developed as a safe pharmaceutical component for the prevention of photoaging and skin inflammation.

Corrigendum: Doxycycline Inhibits Cancer Stem Cell-Like Properties via PAR1/FAK/PI3K/AKT Pathway in Pancreatic Cancer.

[This corrects the article DOI: 10.3389/fonc.2020.619317.].

Psychologic Stress Drives Progression of Malignant Tumors via DRD2/HIF1α Signaling.

Although it is established that the sustained psychologic stress conditions under which patients with tumors often reside accelerates malignant progression of tumors, the molecular mechanism behind this association is unclear. In this work, the effect of psychologic stress on tumor progression was verified using a stress-stimulated tumor-bearing mouse model (Str-tumor). Both D2 dopamine receptor (DRD2) and hypoxia-inducible factor-1α (HIF1α) were highly expressed in the nucleus of Str-tumors. Treatment with trifluoperazine (TFP), a DRD2 inhibitor, elicited better antitumor effects in Str-tumors than the control group. These results indicate that DRD2 may mediate stress-induced malignant tumor progression. DRD2 interacted with von Hippel-Lindau (VHL) in the nucleus, and competitive binding of DRD2 and HIF1α to VHL resulted in reduced ubiquitination-mediated degradation of HIF1α, enhancing the epithelial-mesenchymal transition of tumor cells. TFP acted as an interface inhibitor between DRD2 and VHL to promote the degradation of HIF1α. In conclusion, DRD2 may promote the progression of malignant tumors induced by psychologic stress via activation of the oxygen-independent HIF1α pathway, and TFP may serve as a therapeutic strategy for stress management in patients with cancer. SIGNIFICANCE: This work identifies DRD2 regulation of HIF1α as a mechanism underlying the progression of malignant tumors stimulated by psychologic stress and suggests that DRD2 inhibition can mitigate these stress conditions in patients.See related commentary by Bernabé, p. 5144.

Salidroside can target both P4HB-mediated inflammation and melanogenesis of the skin.

Rationale: Many external factors can induce the melanogenesis and inflammation of the skin. Salidroside (SAL) is the main active ingredient of Rhodiola, which is a perennial grass plant of the Family Crassulaceae. This study evaluated the effect and molecular mechanism of SAL on skin inflammation and melanin production. It then explored the molecular mechanism of melanin production under ultraviolet (UV) and inflammatory stimulation. Methods: VISIA skin analysis imaging system and DermaLab instruments were used to detect the melanin reduction and skin brightness improvement rate of the volunteers. UV-treated Kunming mice were used to detect the effect of SAL on skin inflammation and melanin production. Molecular docking and Biacore were used to verify the target of SAL. Immunofluorescence, luciferase reporter assay, CO-IP, pull-down, Western blot, proximity ligation assay (PLA), and qPCR were used to investigate the molecular mechanism by which SAL regulates skin inflammation and melanin production. Results: SAL can inhibit the inflammation and melanin production of the volunteers. SAL also exerted a protective effect on the UV-treated Kunming mice. SAL can inhibit the tyrosinase (TYR) activity and TYR mRNA expression in A375 cells. SAL can also regulate the ubiquitination degradation of interferon regulatory factor 1 (IRF1) by targeting prolyl 4-hydroxylase beta polypeptide (P4HB) to mediate inflammation and melanin production. This study also revealed that IRF1 and upstream stimulatory factor 1 (USF1) can form a transcription complex to regulate TYR mRNA expression. IRF1 also mediated inflammatory reaction and TYR expression under UV- and lipopolysaccharide-induced conditions. Moreover, SAL derivative SAL-plus (1-(3,5-dihydroxyphenyl) ethyl-ß-d-glucoside) showed better effect on inflammation and melanin production than SAL. Conclusion: SAL can inhibit the inflammation and melanogenesis of the skin by targeting P4HB and regulating the formation of the IRF1/USF1 transcription complex. In addition, SAL-plus may be a new melanin production and inflammatory inhibitor.

Doxycycline Inhibits Cancer Stem Cell-Like Properties via PAR1/FAK/PI3K/AKT Pathway in Pancreatic Cancer.

Pancreatic cancer stem cells (CSCs) play an important role in the promotion of invasion and metastasis of pancreatic cancer. Protease activation receptor 1 (PAR1) is closely related to malignant progression of tumors, however, its effects on pancreatic cancer stem cell-like (CSC-like) properties formation have not been reported. In this work, the effects of PAR1 on pancreatic cancer stem cell-like (CSC-like) properties formation were studied. PAR1 overexpression can induce CSC-like properties in Aspc-1 cells, whereas interference of PAR1 in Panc-1 cells showed the contrary results. Data on patients with pancreatic cancer obtained from TCGA showed that high PAR1 expression and focal adhesion kinase (FAK) protein considerably affect the prognosis of patients. Further experiments showed that PAR1 could regulate FAK, PI3K, and AKT phosphorylation and the epithelial-mesenchymal transformation (EMT) in Aspc-1 and Panc-1 cells. Doxycycline, as a PAR1 inhibitor, could effectively inhibit the CSC-like properties of pancreatic cancer cells and the FAK/PI3K/AKT pathway activation. Doxycycline inhibits the growth of pancreatic cancer and enhances the treatment effect of 5-fluorouracil (5-FU) in Panc-1 xenograft mouse model. In conclusion, PAR1 promotes the CSC-like properties and EMT of pancreatic cancer cells via the FAK/PI3K/AKT pathway. Doxycycline inhibits the pancreatic cancer through the PAR1/FAK/PI3K/AKT pathway and enhances the therapeutic effect of 5-FU.