Novel ProTide prodrugs of 5-fluoro-2'-deoxyuridine for the treatment of liver cancer.

ProTide prodrug technology has emerged as a promising way for the development of anti-viral and anti-tumor drugs, whereas, there are fewer applications for the treatment of liver cancer. Herein, a series of distinct 3'-ester ProTide prodrugs of 5-fluoro-2'-deoxyuridine (FdUR) were synthesized and evaluated for their anti-liver cancer activity. The most efficient prodrug 11b reached a sub-micromolar activity (IC50 = 0.42 ± 0.13 µM) against HepG2 and over 100-fold and 200-fold improvements compared to 5-FU, respectively. 11b also demonstrated favorable selectivity towards normal liver cells L-02 (IC50 > 100 µM). In vitro metabolic stability studies revealed that 11b is stable in the plasma and could be activated rapidly in the liver, which supported that 11b is liver-targeted. Importantly, to more accurately evaluate the anti-HCC activity of 11b, the liver orthotopic model was built and 11b significantly suppressed tumor growth (TGI = 75.5%) at a dose of 60 mg/kg/2d in vivo without obvious toxicity. Overall, these promising results indicated that 11b could serve as a safe and effective prodrug of 5-FU nucleoside for liver cancer therapy.

Translocation of IGF-1R in endoplasmic reticulum enhances SERCA2 activity to trigger Ca2+ER perturbation in hepatocellular carcinoma.

The well-known insulin-like growth factor 1 (IGF1)/IGF-1 receptor (IGF-1R) signaling pathway is overexpressed in many tumors, and is thus an attractive target for cancer treatment. However, results have often been disappointing due to crosstalk with other signals. Here, we report that IGF-1R signaling stimulates the growth of hepatocellular carcinoma (HCC) cells through the translocation of IGF-1R into the ER to enhance sarco-endoplasmic reticulum calcium ATPase 2 (SERCA2) activity. In response to ligand binding, IGF-1Rß is translocated into the ER by ß-arrestin2 (ß-arr2). Mass spectrometry analysis identified SERCA2 as a target of ER IGF-1Rß. SERCA2 activity is heavily dependent on the increase in ER IGF-1Rß levels. ER IGF-1Rß phosphorylates SERCA2 on Tyr990 to enhance its activity. Mutation of SERCA2-Tyr990 disrupted the interaction of ER IGF-1Rß with SERCA2, and therefore ER IGF-1Rß failed to promote SERCA2 activity. The enhancement of SERCA2 activity triggered Ca2+ER perturbation, leading to an increase in autophagy. Thapsigargin blocked the interaction between SERCA2 and ER IGF-1Rß and therefore SERCA2 activity, resulting in inhibition of HCC growth. In conclusion, the translocation of IGF-1R into the ER triggers Ca2+ER perturbation by enhancing SERCA2 activity through phosphorylating Tyr990 in HCC.

Activation of insulin-like growth factor-1 receptor (IGF-1R) promotes growth of colorectal cancer through triggering the MEX3A-mediated degradation of RIG-I.

Insulin-like growth factor-1 receptor (IGF-1R) has been made an attractive anticancer target due to its overexpression in cancers. However, targeting it has often produced the disappointing results as the role played by cross talk with numerous downstream signalings. Here, we report a disobliging IGF-1R signaling which promotes growth of cancer through triggering the E3 ubiquitin ligase MEX3A-mediated degradation of RIG-I. The active ß-arrestin-2 scaffolds this disobliging signaling to talk with MEX3A. In response to ligands, IGF-1Rß activated the basal ßarr2 into its active state by phosphorylating the interdomain domain on Tyr64 and Tyr250, opening the middle loop (Leu130‒Cys141) to the RING domain of MEX3A through the conformational changes of ßarr2. The models of ßarr2/IGF-1Rß and ßarr2/MEX3A could interpret the mechanism of the activated-IGF-1R in triggering degradation of RIG-I. The assay of the mutants ßarr2Y64A and ßarr2Y250A further confirmed the role of these two Tyr residues of the interlobe in mediating the talk between IGF-1Rß and the RING domain of MEX3A. The truncated-ßarr2 and the peptide ATQAIRIF, which mimicked the RING domain of MEX3A could prevent the formation of ßarr2/IGF-1Rß and ßarr2/MEX3A complexes, thus blocking the IGF-1R-triggered RIG-I degradation. Degradation of RIG-I resulted in the suppression of the IFN-I-associated immune cells in the TME due to the blockade of the RIG-I-MAVS-IFN-I pathway. Poly(I:C) could reverse anti-PD-L1 insensitivity by recovery of RIG-I. In summary, we revealed a disobliging IGF-1R signaling by which IGF-1Rß promoted cancer growth through triggering the MEX3A-mediated degradation of RIG-I.

Design, synthesis, and evaluation of JTE-013 derivatives as novel potent S1PR2 antagonists for recovering the sensitivity of colorectal cancer to 5-fluorouracil.

Targeting sphingosine-1-phosphate receptor 2 (S1PR2) has been proved as a promising strategy to reverse 5-fluorouracil (5-FU) resistance. Here, we report the discovery of the novel JTE-013 derivative compound 37 h as a more effective S1PR2 antagonist to reverse 5-FU resistance in SW620/5-FU and HCT116DPD cells than JTE-013 and previously reported compound 5. Compound 37 h could effectively bind S1PR2 and reduce its expression, thus leading to decreased expression of JMJD3 and dihydropyrimidine dehydrogenase (DPD), while also increasing the level of H3K27me3 to decrease the degradation of 5-FU and thereby increase its intracellular concentration in SW620/5-FU, HCT116DPD, and L02 cells. Furthermore, compound 37 h showed good selectivity to other S1PRs and normal colon cell line NCM460. Western blot analysis demonstrated that compound 37 h could abrogate the FBAL-stimulated upregulation of DPD expression by S1PR2. Importantly, compound 37 h also showed favorable metabolic stability with a long half-life (t1/2) of 7.9 h. Moreover, compound 37 h significantly enhanced the antitumor efficacy of 5-FU in the SW620/5-FU animal model. Thus, the JTE-013-based derivative compound 37 h represents a promising lead compound for the development of novel 5-FU sensitizers for colorectal cancer (CRC) therapy.

Rational Design, Synthesis, and Biological Evaluation of Novel S1PR2 Antagonists for Reversing 5-FU-Resistance in Colorectal Cancer.

Resistance to 5-FU reduces its clinical efficacy for the treatment of colorectal cancer. Sphingosine-1-phosphate receptor 2 (S1PR2) has emerged as a potential target to reverse 5-FU-resistance by inhibiting the expression of dihydropyrimidine dehydrogenase (DPD). In this study, 38 novel S1PR2 antagonists based on aryl urea structure were designed and synthesized, and the structure-activity relationship was investigated based on the S1PR2 binding assay. Representative compound 43 potently interacts with S1PR2 with a KD value of 0.73 nM. It displays potent 5-FU resensitizing activity in multiple 5-FU-resistant tumor cell lines, particularly in SW620/5-FU (EC50 = 1.99 ± 0.03 µM) but shows no cytotoxicity in the normal colon cell line NCM460 up to 1000 µM. Moreover, 43 significantly enhances the antitumor efficacy of 5-FU in the SW620/5-FU animal model. These data suggest that 43 could be a novel lead compound for developing a 5-FU resensitizing agent.

Intestinal aberrant sphingolipid metabolism shaped-gut microbiome and bile acids metabolome in the development of hepatic steatosis.

Conjugated bile acids (CBAs) play major roles in hepatic gene regulation via nuclear S1P-inhibited histone deacetylase (HDACs). Gut microbiota modifies bile acid pool to generate CBAs and then CBAs returned to liver to regulate hepatic genes, fatty liver, and non-alcoholic fatty liver disease (NAFLD). However, it is not yet known how the gut microbiota was modified under the environment of inflammatory bowel disease (IBD). Here, we revealed that aberrant intestinal sphingosine kinases (SphKs), a major risk factor of IBD, modified gut microbiota by increasing the proportions of Firmicutes and Verrucomicrobia, which were associated with the increase in CBAs. When exposed to a high-fat diet (HFD), sphingosine kinases 2 knockout (SphK2KO) mice developed more severity of intestinal inflammation and hepatic steatosis than their wild-type (WT) littermates. Due to knockdown of nuclear SphK2, Sphk2KO mice exhibited an increase in sphingosine kinases 1 (SphK1) and sphingosine-1-phosphate (S1P) in intestinal epithelial cells. Therefore, the microbiota was modified in the environment of the SphK1/S1P-induced IBD. 16S rDNA amplicon sequencing of cecal contents indicated an increase of Firmicutes and Verrucomicrobia. Ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) measured an increase in CBAs, including taurocholic acid (TCA), taurodeoxycholic acid (TDCA), and glycocholic acid (GCA), in cecal contents and liver tissues of Sphk2KO mice. These CBAs accumulated in the liver promoted hepatic steatosis through downregulating the acetylation of H3K9, H3K14, H3K18 and H3K27 due to the CBAs-S1PR2-nuclear SphK2-S1P signaling pathway was blocked in HFD-SphK2KO mice. In summary, intestinal aberrant sphingolipid metabolism developed hepatic steatosis through the increase in CBAs associated with an increase in Firmicutes and Verrucomicrobia.

Exosomal miR-146a-5p and miR-155-5p promote CXCL12/CXCR7-induced metastasis of colorectal cancer by crosstalk with cancer-associated fibroblasts.

C-X-C motif chemokine receptor 7 (CXCR7) is a newly discovered atypical chemokine receptor that binds to C-X-C motif chemokine ligand 12 (CXCL12) with higher affinity than CXCR4 and is associated with the metastasis of colorectal cancer (CRC). Cancer-associated fibroblasts (CAFs) have been known to promote tumor progression. However, whether CAFs are involved in CXCR7-mediated metastasis of CRC remains elusive. We found a significant positive correlation between CXCR7 expression and CAF activation markers in colonic tissues from clinical specimens and in villin-CXCR7 transgenic mice. RNA sequencing revealed a coordinated increase in the levels of miR-146a-5p and miR-155-5p in CXCR7-overexpressing CRC cells and their exosomes. Importantly, these CRC cell-derived miR-146a-5p and miR-155-5p could be uptaken by CAFs via exosomes and promote the activation of CAFs through JAK2-STAT3/NF-κB signaling by targeting suppressor of cytokine signaling 1 (SOCS1) and zinc finger and BTB domain containing 2 (ZBTB2). Reciprocally, activated CAFs further potently enhanced the invasive capacity of CRC cells. Mechanistically, CAFs transfected with miR-146a-5p and miR-155-5p exhibited a robust increase in the levels of inflammatory cytokines interleukin-6, tumor necrosis factor-α, transforming growth factor-ß, and CXCL12, which trigger the epithelial-mesenchymal transition and pro-metastatic switch of CRC cells. More importantly, the activation of CAFs by miR-146a-5p and miR-155-5p facilitated tumor formation and lung metastasis of CRC in vivo using tumor xenograft models. Our work provides novel insights into CXCR7-mediated CRC metastasis from tumor-stroma interaction and serum exosomal miR-146a-5p and miR-155-5p could serve as potential biomarkers and therapeutic targets for inhibiting CRC metastasis.

Atypical chemokine receptor 3 induces colorectal tumorigenesis in mice by promoting ß-arrestin-NOLC1-fibrillarin-dependent rRNA biogenesis.

Atypical chemokine receptor 3 (ACKR3) has emerged as a key player in various biological processes. Its atypical "intercepting receptor" properties have established ACKR3 as the major regulator in the pathophysiological processes in many diseases. In this study, we investigated the role of ACKR3 activation in promoting colorectal tumorigenesis. We showed that ACKR3 expression levels were significantly increased in human colon cancer tissues, and high levels of ACKR3 predicted the increased severity of cancer. In Villin-ACKR3 transgenic mice with a high expression level of CKR3 in their intestinal epithelial cells, administration of AOM/DSS induced more severe colorectal tumorigenesis than their WT littermates. Cancer cells of Villin-ACKR3 transgenic mice were characterised by the nuclear ß-arrestin-1 (ß-arr1)-activated perturbation of rRNA biogenesis. In HCT116 cells, cotreatment with CXCL12 and AMD3100 selectively activated ACKR3 and induced nuclear translocation of ß-arr1, leading to an interaction of ß-arr1 with nucleolar and coiled-body phosphoprotein 1 (NOLC1). NOLC1, as the phosphorylated protein, further interacted with fibrillarin, a conserved nucleolar methyltransferase responsible for ribosomal RNA methylation in the nucleolus, thereby increasing the methylation in histone H2A and promoting rRNA transcription in ribosome biogenesis. In conclusion, ACKR3 promotes colorectal tumorigenesis through the perturbation of rRNA biogenesis by the ß-arr1-induced interaction of NOLC1 with fibrillarin.

ZnO nanoparticles promote the malignant transformation of colorectal epithelial cells in APCmin/+ mice.

As the use of zinc oxide nanoparticles (ZnO NPs) in everyday products grows, so does concern about health risks. However, no findings on the gastrointestinal toxicity of ZnO NPs have been published. We investigated the possible malignant transformation of ZnO NPs in the mice's colonic tissues using the APCmin/+ mouse model with a premalignant lesion in intestinal epithelial cells. Higher doses and long-term oral exposure to ZnO NPs were found to mildly promote colonic inflammation in WT mice, while they moderately or strongly exacerbated the severity of chronic inflammation and tumorigenesis in APCmin/+ mice with intestinal adenomatous polyposis. The ZnO NPs-induced inflammation and tumorigenesis in colonic epithelial cells was linked to the activation of CXCR2/NF-κB/STAT3/ERK and AKT pathways. Analysis of the ZnO NPs-exacerbated intestinal adenomatous polyposis in APCmin/+ mice revealed that ZnO NPs could activate the APC-driven Wnt/ß-catenin signaling pathway, exacerbating intestinal tumorigenesis. In fact, ZnO NPs have been shown to increase intestinal inflammation and tumorigenesis in APCmin/+ mice by releasing free Zn2+. In WT mice, a low dose of ZnO NPs (26 mg/kg/day) did not cause intestinal inflammation. In conclusion, higher doses and prolonged exposure to ZnO NPs promote the malignant transformation of precancerous epithelial cells.

Novel 5-fluorouracil sensitizers for colorectal cancer therapy: Design and synthesis of S1P receptor 2 (S1PR2) antagonists.

Sphingosine-1-phosphate receptor 2 (S1PR2) has been identified as a brand-new GPCR target for designing antagonists to reverse 5-FU resistance. We herein report the structural optimization and structure-activity relationship of JTE-013 derivatives as S1PR2 antagonists. Compound 9d was the most potent S1PR2 antagonist (KD = 34.8 nM) among developed compounds. Here, compound 9d could significantly inhibit the expression of dihydropyrimidine dehydrogenase (DPD) to reverse 5-FU-resistance in HCT116DPD and SW620/5-FU cells. Further mechanism studies demonstrated that compound 9d not only inhibited S1PR2 but also affected the transcription of S1PR2. In addition, compound 9d also showed acceptable selectivity to normal cells (NCM460). Importantly, compound 9d with suitable pharmacokinetic properties could significantly reverse 5-FU-resistance in the HCT116DPD and SW620/5-FU xenograft models without obvious toxicity, in which the inhibition rates of 5-FU were increased from 23.97% to 65.29% and 27.23% to 60.81%, respectively. Further immunohistochemistry and western blotting analysis also demonstrated that compound 9d significantly decreases the expression of DPD in tumor and liver tissues. These results indicated that compound 9d is a promising lead compound to reverse 5-FU-resistance for colorectal cancer therapy.

Design, synthesis and biological evaluation of sphingosine-1-phosphate receptor 2 antagonists as potent 5-FU-resistance reversal agents for the treatment of colorectal cancer.

5-Fluorouracil (5-FU) and its prodrugs are the essential clinical drugs for colorectal cancer (CRC) treatment. However, the drug resistance of 5-FU has caused high mortality of CRC patients. Thus, it is urgent to develop reversal agents of 5-FU resistance. Sphingosine-1-phosphate receptor 2 (S1PR2) was proved to be a potential target for reversing 5-FU resistance, but the activity of known S1PR2 antagonists JTE-013 were weak in 5-FU-resistant cell lines. To develop more potent S1PR2 antagonists to treat 5-FU-resistant cancer, a series of JTE-013 derivatives were designed and synthesized. The most promising compound 40 could markedly reverse the resistance in 5-FU-resistant HCT116 cells and 5-FU-resistant SW620 cells via inhibiting the expression of dihydropyrimidine dehydrogenase (DPD). The key was that compound 40 with improved pharmacokinetic properties significantly increased the inhibitory rate of 5-FU in the SW620/5-FU cells xenograft model with no observable toxicity by inhibiting the expression of DPD in tumor and liver tissues. Altogether, these results suggest that compound 40 may be a promising drug candidate to reverse 5-FU resistance in the treatment of CRC.

Myricetin and M10, a myricetin-3-O-ß-d-lactose sodium salt, modify composition of gut microbiota in mice with ulcerative colitis.

Our previous studies found that M10, a myricetin-3-O-ß-d-lactose sodium salt, possessed higher effects of ameliorating ulcerative colitis (UC) than Myricetin in mice. Here, we aim to investigate whether the inhibition of UC is the consequence of the effects of M10 that leads to the changed microbiota. Mice model of UC was induced by dextran sulfate sodium (DSS) treatment. M10 and Myricetin were orally administrated for 12 weeks. We performed 16S rDNA sequencing assay to analyze the composition of gut microbiota isolated from ileocecum. Both M10 and Myricetin normalized the composition of Firmicutes and Actinobacteria as healthy mice had. At genus level, the effects of M10 and Myricetin on colitis were associated to the increase of probiotics, such as Akkermansia, and the inhibition of pathogenic microorganisms, such as Ruminococcus and Parabacteroides. M10 had stronger activity than Myricetin in the improvement of biosynthesis and degradation activities, resulting to increasing metabolism of sulfur, pyruvate, steroid biosynthesis and unsaturated fatty acid biosynthesis in gut. Furthermore, M10 normalized the proportion of Firmicutes and Actinobacteria in gut microbiota. It suggests that the improvements in UC are the consequence of the effect of M10 that leads to the changed intestinal microbiota. Conclusion: M10 contributed the pharmacological effects on UC by modification of the intestinal microbiota.

Nuclear translocation of ATG5 induces DNA mismatch repair deficiency (MMR-D)/microsatellite instability (MSI) via interacting with Mis18α in colorectal cancer.

BACKGROUND AND PURPOSE: It is well known that microsatellite instability-high (MSI-H) is associated with 5-fluorouracil (5-FU) resistance in colorectal cancer. MSI-H is the phenotype of DNA mismatch repair deficiency (MMR-D), mainly occurring due to hypermethylation of MLH1 promoter CpG island. However, the mechanisms of MMR-D/MSI-H are unclear. We aim to investigate the pathway of MMR-D/MSI-H involved in 5-FU resistance. EXPERIMENTAL APPROACH: Human colorectal cancer specimens were diagnosed for MSI-H by immunohistochemistry and western blotting. Proteome microarray interactome assay was performed to screen nuclear proteins interacting with ATG5. Nuclear ATG5 and ATG5-Mis18α overexpression were analysed in ATG5high colorectal cancer bearing mice. The methylation assay determined the hypermethylation of hMLH1 promoter CpG island in freshly isolated human colorectal cancer tissue samples and HT29atg5 and SW480atg5 cancer cells. KEY RESULTS: In ATG5high colorectal cancer patients, 5-FU-based therapy resulted in nuclear translocation of ATG5, leading to MSI-H. Colorectal cancer in Atg5 Tg mice demonstrated 5-FU resistance, compared to Atg5+/- and WT mice. Proteome microarray assay identified Mis18α, a protein localized on the centromere and a source for methylation of the underlying chromatin, which responded to the translocated nuclear ATG5 leading to ATG5-Mis18α conjugate overexpression. This resulted in MLH1 deficiency due to hypermethylation of hMLH1 promoter CpG island, while the deletion of nuclear Mis18α failed to induce ATG5-Mis18α complex and MMR-D/MSI-H. CONCLUSIONS AND IMPLICATIONS: Nuclear ATG5 resulted in MMR-D/MSI-H through its interaction with Mis18α in ATG5high colorectal cancer cells. We suggest that ATG5-Mis18α or Mis18α may be a therapeutic target for treating colorectal cancer.

Increased S1P induces S1PR2 internalization to blunt the sensitivity of colorectal cancer to 5-fluorouracil via promoting intracellular uracil generation.

Sphingosine-1-phosphate (S1P), the backbone of most sphingolipids, activating S1P receptors (S1PRs) and the downstream G protein signaling has been implicated in chemoresistance. In this study we investigated the role of S1PR2 internalization in 5-fluorouracil (5-FU) resistance in human colorectal cancer (CRC). Clinical data of randomly selected 60 CRC specimens showed the correlation between S1PR2 internalization and increased intracellular uracil (P < 0.001). Then we explored the regulatory mechanisms in CRC model of villin-S1PR2-/- mice and CRC cell lines. We showed that co-administration of S1P promoted S1PR2 internalization from plasma membrane (PM) to endoplasmic reticulum (ER), thus blunted 5-FU efficacy against colorectal tumors in WT mice, compared to that in S1PR2-/- mice. In HCT116 and HT-29 cells, application of S1P (10 µM) empowered S1PR2 to internalize from PM to ER, thus inducing 5-FU resistance, whereas the specific S1PR2 inhibitor JTE-013 (10 µM) effectively inhibited S1P-induced S1PR2 internalization. Using Mag-Fluo-AM-labeling [Ca2+]ER and LC-ESI-MS/MS, we revealed that internalized S1PR2 triggered elevating [Ca2+]ER levels to activate PERK-eLF2α-ATF4 signaling in HCT116 cells. The activated ATF4 upregulated RNASET2-mediated uracil generation, which impaired exogenous 5-FU uptake to blunt 5-FU therapy. Overall, this study reveals a previously unrecognized mechanism of 5-FU resistance resulted from S1PR2 internalization-upregulated uracil generation in colorectal cancer, and provides the novel insight into the significance of S1PR2 localization in predicting the benefit of CRC patients from 5-FU-based chemotherapy.

M10, a Myricetin-3-O-b-D-Lactose Sodium Salt, Prevents Ulcerative Colitis Through Inhibiting Necroptosis in Mice.

BACKGROUND: M10 is a derivative of Myricetin by adding a hydrophilic glycosylation group. Our previous study revealed that M10 by oral administration prevented colitis-associated colonic cancer (CAC) through attenuating endoplasmic reticulum stress in mice. In current study, we evaluated the inhibitory effects of M10 on ulcerative colitis in mice model, the mechanism of M10 in preventing colitis was further investigated. METHODS: Mice model of ulcerative colitis was induced by continuous oral dextran sodium sulfate (DSS). M10 was given gavage once a day for 12 consecutive weeks. Disease activity index (DAI) was recorded by analyzing the symptoms of colitis. Intestinal barrier was analyzed by the Immunofluorescence staining assay. The structure of microvilli of intestinal epithelial cells was analyzed under Transmission electron microscopy (TEM). TEM assay was also performed to determine the formation of necroptosis in the colonic epithelium with ulcerative colitis. We performed Western blotting assay to analyze the IL-6 and NF-κB pathways, as well as the cytokine cascades related to TNF-α signaling pathway during necroptosis. RESULTS: M10 by oral administration demonstrated a prevention of ulcerative colitis, showing a significant decrease of DAI as compared to the model mice. Pathological analysis indicated that M10 attenuated the degree of colonic inflammation in colonic tissues. M10 restored the structures of intestinal barrier damaged by DSS. M10 prevented the activation of the IL-6 and NF-κB signaling pathways in the inflamed colonic epithelium. Further, M10 prevented necroptosis in the inflamed colonic mucosal cells through down-regulating the TNF-α pathway. Importantly, M10 demonstrated higher activities in preventing ulcerative colitis than Myricetin and control drug Mesalazine. CONCLUSIONS: Myricetin derivative M10 prevents chronic ulcerative colitis through inhibiting necroptosis. M10 could be developed as a promising drug for the treatment of chronic ulcerative colitis.

SphK2 confers 5-fluorouracil resistance to colorectal cancer via upregulating H3K56ac-mediated DPD expression.

Aberrant sphingolipid metabolism has been implicated in chemoresistance, but the underlying mechanisms are still poorly understood. Herein we revealed a previously unrecognized mechanism of 5-fluorouracil (5-FU) resistance contributed by high SphK2-upregulated dihydropyrimidine dehydrogenase (DPD) in colorectal cancer (CRC), which is evidenced from human CRC specimens, animal models, and cancer cell lines. TMA samples from randomly selected 60 CRC specimens firstly identified the clinical correlation between high SphK2 and increased DPD (p < 0.001). Then the regulatory mechanism was explored in CRC models of villin-SphK2 Tg mice, SphK2-/-mice, and human CRC cells xenografted nude mice. Assays of ChIP-Seq and luciferase reporter gene demonstrated that high SphK2 upregulated DPD through promoting the HDAC1-mediated H3K56ac, leading to the degradation of intracellular 5-FU into inactive α-fluoro-ß-alanine (FBAL). Lastly, inhibition of SphK2 by SLR080811 exhibited excellent inhibition on DPD expression and potently reversed 5-FU resistance in colorectal tumors of villin-SphK2 Tg mice. Overall, this study manifests that SphK2high conferred 5-FU resistance through upregulating tumoral DPD, which highlights the strategies of blocking SphK2 to overcome 5-FU resistance in CRC.

Exposure to low dose ZnO nanoparticles induces hyperproliferation and malignant transformation through activating the CXCR2/NF-κB/STAT3/ERK and AKT pathways in colonic mucosal cells.

As ZnO nanoparticles have been applied in many fields, their biological risks on human health, of course, are worthy of our attention. Whether ZnO NPs have the risk and how colonic cells respond to the invaded ZnO NPs are still unknown. Herein, we evaluated the biological effects of ZnO NPs on colonic mucosal cells by in vitro and in vivo methods. IMCE cells, with APC mutation but phenotypically normal, demonstrated hyperproliferation through activating the CXCR2/NF-κB/STAT3/ERK and AKT pathways when exposed to ZnO NPs for 24 h. Long-term exposure of ZnO NPs resulted in the malignant transformation of IMCE cells, showing the morphological changes, anchorage-independent cell growth ability. Importantly, IMCE cells exposed to ZnO NPs subcutaneously grew and induced tumorigenesis in nude mice. In conclusion, exposure of ZnO NPs could induce malignant transformation of colonic mucosal cells through the CXCR2/NF-κB/STAT3/ERK and AKT pathways. We suggest that it was necessary to consider using the precautionary principle for gastrointestinal contact nanomaterials.

Exosome-encapsulated miRNAs contribute to CXCL12/CXCR4-induced liver metastasis of colorectal cancer by enhancing M2 polarization of macrophages.

Tumor-associated macrophages (TAMs) are important immunocytes associated with cancer metastasis. However, whether TAMs play a dominant role in mediating CXCL12/CXCR4-induced liver metastasis of colorectal cancer (CRC) remains unexplored. Herein, we found that CD206+ TAMs, which infiltrated at the invasive front, were correlated with CXCR4 expression and liver metastasis of CRC in clinical specimens. Several miRNAs (miR-25-3p, miR-130b-3p, miR-425-5p), upregulated in CRC cells by activation of the CXCL12/CXCR4 axis, could be transferred to macrophages via exosomes. These exosomal miRNAs induced M2 polarization of macrophages by regulating PTEN through activation of PI3K/Akt signaling pathway. In turn, M2 polarized macrophages promoted cancer metastasis by enhancing epithelial-mesenchymal transition (EMT) and secreting vascular endothelial growth factor (VEGF). Co-culture of CRC cells with macrophages transfected with these miRNAs or treated with exosomes enhanced their metastatic capacity both in vitro and in vivo. Clinically, the serum levels of exosomal miR-25-3p, miR-130b-3p and miR-425-5p were correlated with progression and metastasis of CRC. In conclusion, these results reveal a crucial role of exosomal miRNAs in mediating the crosstalk between CXCR4 overexpressing cancer cells and TAMs, providing potential therapeutic targets for circumventing liver metastasis of CRC.