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Establishing a valid in vitro model to represent tumor heterogeneity and biology is critical but challenging. Tumor organoids are self‐assembled three‐dimensional cell clusters which are of great significance for recapitulating the histopathological, genetic, and phenotypic characteristics of primary tissues. The organoid has emerged as an attractive in vitro platform for tumor biology research and high‐throughput drug screening in cancer medicine. Organoids offer unique advantages over cell lines and patient‐derived xenograft models, but there are no standardized methods to guide the culture of organoids, leading to confusion in organoid studies that may affect accurate judgments of tumor biology. This review summarizes the shortcomings of current organoid culture methods, presents the latest research findings on organoid standardization, and proposes an outlook for organoid modeling. [ABSTRACT FROM AUTHOR]

Doxorubicin is the most frequently used chemotherapeutic agent for the treatment of hepatocellular carcinoma. However, one major obstacle to the effective management of liver cancer is the drug resistance derived from the cancer stem cells. Herein, we employed a CD133 aptamer for targeted delivery of doxorubicin into liver cancer stem cells to overcome chemoresistance. Furthermore, we explored the efficacy of autophagy inhibition to sensitize liver cancer stem cells to the treatment of CD133 aptamer-doxorubicin conjugates based on the previous observation that doxorubicin contributes to the survival of liver cancer stem cells by activating autophagy. The kinetics and thermodynamics of aptamer-doxorubicin binding, autophagy induction, cell apoptosis, and self-renewal of liver cancer stem cells were studied using isothermal titration calorimetry, Western blot analysis, annexin V assay, and tumorsphere formation assay. The aptamer-cell binding andintracellular accumulation of doxorubicin were quantified via flow cytometry. CD133 aptamer-guided delivery of doxorubicin resulted in a higher doxorubicin concentration in the liver cancer stem cells. The combinatorial treatment strategy of CD133 aptamer-doxorubicin conjugates and an autophagy inhibitor led to an over 10-fold higher elimination of liver cancer stem cells than that of free doxorubicin in vitro. Future exploration of cancer stem cell-targeted delivery of doxorubicin in conjunction with autophagy inhibition in vivo may well lead to improved outcomes in the treatment of hepatocellular carcinoma. [ABSTRACT FROM AUTHOR]

Besides its well‐known benefits on human health, calcitriol, the hormonally active form of vitamin D3, has been being evaluated in clinical trials as an anticancer agent. However, currently available results are contradictory and not fundamentally deciphered. To the best of our knowledge, hypercalcemia caused by high‐dose calcitriol administration and its low bioavailability limit its anticancer investigations and translations. Here, we show that the one‐step self‐assembly of calcitriol and amphiphilic cholesterol‐based conjugates leads to the formation of a stable minimalist micellar nanosystem. When administered to mice, this nanosystem demonstrates high calcitriol doses in breast tumor cells, significant tumor growth inhibition and antimetastasis capability, as well as good biocompatibility. We further reveal that the underlying molecular antimetastatic mechanisms involve downregulation of proteins facilitating metastasis and upregulation of paxillin, the key protein of focal adhesion, in primary tumors. [ABSTRACT FROM AUTHOR]

Background: The Pregnane X Receptor (PXR) is a principal signal transducer in mucosal responses to xenobiotic stress. It is well-recognized that inflammatory bowel disease is accompanied by xenobiotic stress, but the importance of the PXR in limiting inflammatory responses in inflammatory bowel disease remains obscure at best. Methods: We stimulate a total of 106 colonic biopsies from 19 Crohn’s disease patients with active disease, 36 colonic biopsies from 8 control patients, colonic organoids and various cell culture models (either proficient or genetically deficient with respect to PXR) in vitro with the PXR ligand rifampicin or vehicle. Effects on NF-κB activity are assessed by measuring interleukin-8 (IL-8) and interleukin-1ß (IL-1ß) mRNA levels by qPCR and in cell culture models by NF-κB reporter-driven luciferase activity and Western blot for signal transduction elements. Results: We observe a strict inverse correlation between colonic epithelial PXR levels and NF-κB target gene expression in colonic biopsies from Crohn’s disease patients. PXR, activated by rifampicin, is rate-limiting for mucosal NF-κB activation in IBD. The correlation between colonic epithelial PXR levels and NF-κB target gene expression was also observed in intestinal organoids system. Furthermore, in preclinical in vitro models of intestinal inflammation, including intestinal organoids, genetic inactivation of PXR unleashes NF-κB-dependent signal transduction whereas conversely NF-κB signaling reduces levels of PXR expression. Conclusions: Our data indicate that the PXR is a major and clinically relevant antagonist of NF-κB activity in the intestinal epithelial compartment during inflammatory bowel disease. [ABSTRACT FROM AUTHOR]

Rotavirus infection remains a great health burden worldwide especially in some developing countries. It causes severe dehydrating diarrhea in infants, young children, as well as immunocompromised and organ transplanted patients. Viral replication heavily relies on the host to supply nucleosides. Thus, host enzymes involved in nucleotide biosynthesis represent potential targets for antiviral development. Dihydroorotate dehydrogenase (DHODH) is the rate-limiting enzyme in the de novo biosynthesis pathway of pyrimidines. In this study, we demonstrated that two specific DHODH enzyme inhibitors, brequinar (BQR) and leflunomide (LFM) robustly inhibited rotavirus replication in conventional human intestinal Caco2 cell line as well as in human primary intestinal organoids. The antiviral effect is conserved in both laboratory strain SA11 and rotavirus strain 2011K isolated from clinical sample. Mechanistic study indicated that BQR and LFM exerted their anti-rotavirus effect through targeting DHODH to deplete pyrimidine nucleotide pool. Therefore, targeting pyrimidine biosynthesis represents a potential approach for developing antiviral strategies against rotavirus. • Host enzymes involved in nucleotide biosynthesis represent potential targets for antiviral development. • Dihydroorotate dehydrogenase (DHODH) is the rate-limiting enzyme in the de novo biosynthesis pathway of pyrimidines. • Two specific DHODH enzyme inhibitors, brequinar (BQR) and leflunomide (LFM) robustly inhibited rotavirus replication. • BQR and LFM exerted their anti-rotavirus effect through targeting DHODH to deplete pyrimidine nucleotide pool. [ABSTRACT FROM AUTHOR]

Rotavirus infection has emerged as an important cause of complications in organ transplantation recipients and might play a role in the pathogenesis of inflammatory bowel disease (IBD). 6-Thioguanine (6-TG) has been widely used as an immunosuppressive drug for organ recipients and treatment of IBD in the clinic. This study aims to investigate the effects and mode-of-action of 6-TG on rotavirus replication. Human intestinal Caco2 cell line, 3D model of human primary intestinal organoids, laboratory rotavirus strain (SA11) and patient-derived rotavirus isolates were used. We have demonstrated that 6-TG significantly inhibits rotavirus replication in these intestinal epithelium models. Importantly, gene knockdown or knockout of Rac1, the cellular target of 6-TG, significantly inhibited rotavirus replication, indicating the supportive role of Rac1 for rotavirus infection. We have further demonstrated that 6-TG can effectively inhibit the active form of Rac1 (GTP-Rac1), which essentially mediates the anti-rotavirus effect of 6-TG. Consistently, ectopic over-expression of GTP-Rac1 facilitates but an inactive Rac1 (N17) or a specific Rac1 inhibitor (NSC23766) inhibits rotavirus replication. In conclusion, we have identified 6-TG as an effective inhibitor of rotavirus replication via the inhibition of Rac1 activation. Thus, for transplantation patients or IBD patients infected with rotavirus or at risk of rotavirus infection, the choice of 6-TG as a treatment appears rational. [ABSTRACT FROM AUTHOR]

Rotavirus infection is a major cause of severe dehydrating diarrhea in infants younger than 5 y old and in particular cases of immunocompromised patients irrespective to the age of the patients. Although vaccines have been developed, antiviral therapy is an important complement that cannot be substituted. Because of the lack of specific approved treatment, it is urgent to facilitate the cascade of further understanding of the infection biology, identification of druggable targets and the final development of effective antiviral therapies. PI3K-Akt-mTOR signaling pathway plays a vital role in regulating the infection course of many viruses. In this study, we have dissected the effects of PI3K-Akt-mTOR signaling pathway on rotavirus infection using both conventional cell culture models and a 3D model of human primary intestinal organoids. We found that PI3K-Akt-mTOR signaling is essential in sustaining rotavirus infection. Thus, blocking the key elements of this pathway, including PI3K, mTOR and 4E-BP1, has resulted in potent anti-rotavirus activity. Importantly, a clinically used mTOR inhibitor, rapamycin, potently inhibited both experimental and patient-derived rotavirus strains. This effect involves 4E-BP1 mediated induction of autophagy, which in turn exerts anti-rotavirus effects. These results revealed new insights on rotavirus-host interactions and provided new avenues for antiviral drug development. [ABSTRACT FROM AUTHOR]

Traditional Chinese medicine (TCM) has been an excellent treasury for centuries' accumulation of clinical experiences, which deserves to be tapped for potential drugs and improved using modern scientific methods. 14-Deoxy-11,12-didehydroandrographolide (DAP), a major component of an important TCM named Andrographis paniculata , with non-toxic concentration of 1000 mg/kg/day, effectively reduced the mortality and weight loss of mice lethally challenged with A/chicken/Hubei/327/2004 (H5N1) or A/PR/8/34 (H1N1) influenza A viruses (IAV) when initiated at 4 h before infection, or A/duck/Hubei/XN/2007 (H5N1) when initiated at 4 h or 48 h before infection, or 4 h post-infection (pi). DAP (1000 or 500 mg/kg/day) also significantly diminished lung virus titres of infected mice when initiated at 4 h or 48 h before infection, or 4 h pi. In the infection of A/duck/Hubei/XN/2007 (H5N1), DAP (1000 mg/kg/day) treatment initiated at 48 h before infection gained the best efficacy that virus titres in lungs of mice in log 10 TCID 50 /mL reduced from 2.61 ± 0.14 on 3 days post-infection (dpi), 2.98 ± 0.17 on 5 dpi, 3.54 ± 0.19 on 7 dpi to 1.46 ± 0.14 on 3 dpi, 1.86 ± 0.18 on 5 dpi, 2.03 ± 0.21 on 7 dpi. Moreover, DAP obviously alleviated lung histopathology and also strongly inhibited proinflammatory cytokines/chemokines expression. The mRNA levels of TNF- α , IL-1 β , IL-6, CCL-2/MCP-1, IFN- α , IFN- β , IFN- γ , MIP-1 α , MIP-1 β in lungs of A/duck/Hubei/XN/2007 (H5N1)-infected mice and serum protein expression of TNF- α , IL-1 β , IL-6, CCL-2/MCP-1 and CXCL-10/IP-10 in mice infected with all the three strains of IAV were all significantly reduced by DAP. Results demonstrated that DAP could restrain both the host intense inflammatory responses and high viral load, which were considered to contribute to the pathogenesis of H5N1 virus and should be controlled together in a clinical setting. Considering the anti-inflammatory and anti-IAV activities of DAP, DAP may be a promising active component obtained from A. paniculata , which can be further investigated as a useful constitute of curative strategies in the future against IAV, the H5N1 strains in particular. [ABSTRACT FROM AUTHOR]

Although rotavirus infection is usually acute and self-limiting, it can cause chronic infection with severe diseases in immunocompromised patients, including organ transplantation recipients and cancer patients irrespective of pediatric or adult patients. Since no approved medication against rotavirus infection is available, this study screened a library of safe-in-man broad-spectrum antivirals. We identified gemcitabine, a widely used anti-cancer drug, as a potent inhibitor of rotavirus infection. We confirmed this effect in 2D cell cultures and 3D cultured human intestinal organoids with both laboratory-adapted rotavirus strains and five clinical isolates. Supplementation of UTP or uridine largely abolished the anti-rotavirus activity of gemcitabine, suggesting its function through inhibition of pyrimidine biosynthesis pathway. Our results support repositioning of gemcitabine for treating rotavirus infection, especially for infected cancer patients. • Gemcitabine, a widely used anti-cancer drug, has potent antiviral activity against rotavirus infection. • The antiviral effect of gemcitabine has been confirmed with both laboratory-adapted strains and clinical isolates. • Gemcitabine exerts its anti-rotavirus effect through inhibiting pyrimidine biosynthesis pathway. [ABSTRACT FROM AUTHOR]

The eIF4F complex is a translation initiation factor that closely regulates translation in response to a multitude of environmental conditions including viral infection. How translation initiation factors regulate rotavirus infection remains poorly understood. In this study, the knockdown of the components of the eIF4F complex using shRNA and CRISPR/Cas9 were performed, respectively. We have demonstrated that loss-of-function of the three components of eIF4F, including eIF4A, eIF4E and eIF4G, remarkably promotes the levels of rotavirus genomic RNA and viral protein VP4. Consistently, knockdown of the negative regulator of eIF4F and programmed cell death protein 4 (PDCD4) inhibits the expression of viral mRNA and the VP4 protein. Mechanically, we confirmed that the silence of the eIF4F complex suppressed the protein level of IRF1 and IRF7 that exert potent antiviral effects against rotavirus infection. Thus, these results demonstrate that the eIF4F complex is an essential host factor restricting rotavirus replication, revealing new targets for the development of new antiviral strategies against rotavirus infection. [ABSTRACT FROM AUTHOR]

Norovirus represents the main cause of acute nonbacterial gastroenteritis worldwide. In immunocompromised patients, it bears high risk of causing chronic infection with significant morbidity and mortality. The lack of specific treatment prompts the development of anti-norovirus agents. In this study, we have investigated the role of interferon (IFN) response and evaluated antiviral activities of different IFNs against human norovirus (HuNoV) replication using a HuNoV replicon model. We found that HuNoV RNA replication was sensitive to all types of IFNs, including IFNα (type I), IFNγ (type II), IFNλ1 and 3 (type III). IFNs canonically induce interferon-stimulated genes (ISGs) to exert their antiviral activities. By profiling a subset of important human ISGs using an overexpression approach, we have identified RTP4 and HPSE as moderate anti-norovirus ISGs, whereas IRF-1, RIG-I (also known as DDX58 ) and MDA5 (also known as IFIH1 ) were identified as potent anti-norovirus effectors. Interestingly, type I and III IFNs coordinately induced IRF-1, RIG-I and MDA5; whereas type II IFN predominantly induced IRF-1 to exhibit their anti-norovirus activities. Combination of different IFNs revealed that IFNγ worked cooperatively with type I or type III IFNs to induce ISGs and subsequently inhibit HuNoV replication. Of note, replication of HuNoV did not interfere with antiviral IFN response. In summary, we showed the potent anti-norovirus activities of different types of IFNs and identified the key anti-norovirus effectors. These findings are important for understanding norovirus-host interactions and developing antiviral therapies. [ABSTRACT FROM AUTHOR]

Background: The impact of HBV infection on the prognosis of patients with intrahepatic cholangiocarcinoma (ICC) remains uncertain, and the underlying mechanism has not been elucidated. This study aims to explore the potential mechanism via clinical perspectives and immune features., Methods: We retrospectively reviewed 1308 patients with ICC treated surgically from January 2007 to January 2015. Then, we compared immune-related markers using immunohistochemistry staining to obtain the gene expression profile GSE107943 and related literature for preliminary bioinformatics analysis. Subsequently, we conducted a drug sensitivity assay to validate the role of TNFSF9 in the ICC organoid-autologous immune cell coculture system and in the patient-derived organoids-based xenograft platform., Results: The analysis revealed that tumors in patients without HBV infection exhibited greater size and a higher likelihood of lymphatic metastasis, tumor invasion, and relapse. After resection, HBV-infected patients had longer survival time than uninfected patients (p<0.01). Interestingly, the expression of immune-related markers in HBV-positive patients with ICC was higher than that in uninfected patients (p<0.01). The percentage of CD8+ T cells in HBV-positive tissue was higher than that without HBV infection (p<0.05). We screened 21 differentially expressed genes and investigated the function of TNFSF9 through bioinformatics analyses. The expression of TNFSF9 in ICC organoids with HBV infection was lower than that in organoids without HBV infection. The growth of HBV-negative ICC organoids was significantly inhibited by inhibiting the expression of TNFSF9 with a neutralizing antibody. Additionally, the growth rate was faster in HbsAg (-) ICC patient-derived organoids-based xenograft model than in HbsAg (+) group., Conclusions: The activation of the immune response induced by HBV infection makes the prognosis of HBV-positive patients with ICC differ from that of uninfected patients., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Association for the Study of Liver Diseases.)

Besides its well-known benefits on human health, calcitriol, the hormonally active form of vitamin D 3 , has been being evaluated in clinical trials as an anticancer agent. However, currently available results are contradictory and not fundamentally deciphered. To the best of our knowledge, hypercalcemia caused by high-dose calcitriol administration and its low bioavailability limit its anticancer investigations and translations. Here, we show that the one-step self-assembly of calcitriol and amphiphilic cholesterol-based conjugates leads to the formation of a stable minimalist micellar nanosystem. When administered to mice, this nanosystem demonstrates high calcitriol doses in breast tumor cells, significant tumor growth inhibition and antimetastasis capability, as well as good biocompatibility. We further reveal that the underlying molecular antimetastatic mechanisms involve downregulation of proteins facilitating metastasis and upregulation of paxillin, the key protein of focal adhesion, in primary tumors., Competing Interests: The authors declare that there are no conflict of interests., (© 2021 The Authors. Bioengineering & Translational Medicine published by Wiley Periodicals LLC on behalf of American Institute of Chemical Engineers.)

Biliary atresia (BA) is a neonatal liver disease characterized by progressive fibroinflammatory obliteration of both intrahepatic and extrahepatic bile ducts. The etiologies of BA remain largely unknown, but rotavirus infection has been implicated at least for a subset of patients, and this causal relation has been well demonstrated in mouse models. In this study, we aim to further consolidate this evidence in human biliary organoids. We obtained seven batches of human biliary organoids cultured from fetal liver, adult liver, and bile duct tissues. We found that these organoids are highly susceptible and support the full life cycle of rotavirus infection in three-dimensional culture. The robust infection triggers active virus-host interactions, including interferon-based host defense mechanisms and injury responses. We have observed direct cytopathogenesis in organoids upon rotavirus infection, which may partially recapitulate the development of BA. Importantly, we have demonstrated the efficacy of mycophenolic acid and interferon alpha but not ribavirin in inhibiting rotavirus in biliary organoids. Furthermore, neutralizing antibody targeting rotavirus VP7 protein effectively inhibits infection in organoids. Thus, we have substantiated the causal evidence of rotavirus inducing BA in humans and provided potential strategies to combat the disease. IMPORTANCE There is substantial evidence indicating the possible involvement of rotavirus in biliary atresia (BA) development, at least in a subset of patients, but concrete proof remains lacking. In a mouse model, it has been well demonstrated that rotavirus can infect the biliary epithelium to cause biliary inflammation and obstruction, representing the pathogenesis of BA in humans. By using recently developed organoids technology, we now have demonstrated that human biliary organoids are susceptible to rotavirus infection, and this provokes active virus-host interactions and causes severe cytopathogenesis. Thus, our model recapitulates some essential aspects of BA development. Furthermore, we have demonstrated that antiviral drugs and neutralizing antibodies are capable of counteracting the infection and BA-like morphological changes, suggesting their potential for mitigating BA in patients., (Copyright © 2020 Chen et al.)

Norovirus is the main cause of viral gastroenteritis worldwide. Although norovirus gastroenteritis is self-limiting in immunocompetent individuals, chronic infections with debilitating and life-threatening complications occur in immunocompromised patients. Nitazoxanide (NTZ) has been used empirically in the clinic and has demonstrated effectiveness against norovirus gastroenteritis. In this study, we aimed at uncovering the antiviral potential and mechanisms of action of NTZ and its active metabolite, tizoxanide (TIZ), using a human norovirus (HuNV) replicon. NTZ and TIZ, collectively referred to as thiazolides (TZD), potently inhibited replication of HuNV and a norovirus surrogate, feline calicivirus. Mechanistic studies revealed that TZD activated cellular antiviral response and stimulated the expression of a subset of interferon-stimulated genes (ISGs), particularly interferon regulatory factor 1 (IRF-1), not only in a Huh7 cell-based HuNV replicon, but also in naive Huh7 and Caco-2 cells and novel human intestinal organoids. Overexpression of exogenous IRF-1 inhibited HuNV replication, whereas knockdown of IRF-1 largely attenuated the antiviral activity of TZD, suggesting that IRF-1 mediated TZD inhibition of HuNV. By using a Janus kinase (JAK) inhibitor, CP-690550, and a STAT1 knockout approach, we found that TZD induced antiviral response independently of the classical JAK-signal transducers and activators of transcription (JAK-STAT) pathway. Furthermore, TZD and ribavirin synergized to inhibit HuNV replication and completely depleted the replicons from host cells after long-term treatment. In summary, our results demonstrated that TZD combated HuNV replication through activation of cellular antiviral response, in particular by inducing a prominent antiviral effector, IRF-1. NTZ monotherapy or combination with ribavirin represent promising options for treating norovirus gastroenteritis, especially in immunocompromised patients., (Copyright © 2018 American Society for Microbiology.)