Multi-cohort validation of Ascore: an anoikis-based prognostic signature for predicting disease progression and immunotherapy response in bladder cancer.

Bladder cancer ranks as the 10th most common cancer worldwide, with deteriorating prognosis as the disease advances. While immune checkpoint inhibitors (ICIs) have shown promise in clinical therapy in both operable and advanced bladder cancer, identifying patients who will respond is challenging. Anoikis, a specialized form of cell death that occurs when cells detach from the extracellular matrix, is closely linked to tumor progression. Here, we aimed to explore the anoikis-based biomarkers for bladder cancer prognosis and immunotherapeutic decisions. Through consensus clustering, we categorized patients from the TCGA-BLCA cohort into two clusters based on anoikis-related genes (ARGs). Significant differences in survival outcome, clinical features, tumor immune environment (TIME), and potential ICIs response were observed between clusters. We then formulated a four-gene signature, termed "Ascore", to encapsulate this gene expression pattern. The Ascore was found to be closely associated with survival outcome and served as an independent prognosticator in both the TCGA-BLCA cohort and the IMvigor210 cohort. It also demonstrated superior predictive capacity (AUC = 0.717) for bladder cancer immunotherapy response compared to biomarkers like TMB and PD-L1. Finally, we evaluated Ascore's independent prognostic performance as a non-invasive biomarker in our clinical cohort (Gulou-Cohort1) using circulating tumor cells detection, achieving an AUC of 0.803. Another clinical cohort (Gulou-Cohort2) consisted of 40 patients undergoing neoadjuvant anti-PD-1 treatment was also examined. Immunohistochemistry of Ascore in these patients revealed its correlation with the pathological response to bladder cancer immunotherapy (P = 0.004). Impressively, Ascore (AUC = 0.913) surpassed PD-L1 (AUC = 0.662) in forecasting immunotherapy response and indicated better net benefit. In conclusion, our study introduces Ascore as a novel, robust prognostic biomarker for bladder cancer, offering a new tool for enhancing immunotherapy decisions and contributing to the tailored treatment approaches in this field.

GALNT12 suppresses the bone-specific prostate cancer metastasis by activating BMP pathway via the O-glycosylation of BMPR1A.

Bone metastasis caused the majority death of prostate cancer (PCa) but the mechanism remains poorly understood. In this present study, we show that polypeptide N-acetylgalactosaminyltransferase 12 (GALNT12) suppresses bone-specific metastasis of PCa. GALNT12 suppresses proliferation, migration, invasion and cell division ability of PCa cells by activating the BMP pathway. Mechanistic investigations showed that GALNT12 augments the O-glycosylation of BMPR1A then actives the BMP pathway. Activated BMP signaling inhibits the expression of integrin αVß3 to reduce the bone-specific seeding of PCa cells. Furthermore, activated BMP signaling remolds the immune microenvironment by suppressing the STAT3 pathway. Our results of this study illustrate the role and mechanism of GALNT12 in the process of bone metastasis of PCa and identify GALNT12 as a potential therapeutic target for metastatic PCa.

[Comparative study on three molecular typing methods of Vibrio parahaemolyticus].

OBJECTIVE: To evaluate the correlation among the three molecular typing method of pulsed field gel electrophoresis(PFGE), repetitive extragenic palindromic(REP)-PCR and en-terobacterial repetitive intergenic consensus(ERIC)-PCR, and to explore the genetic relationship among strains, and to further understand the distribution and epidemic trend of Vibrio parahaemolyticus in Liaoning Province by combining Serotype analysis. METHODS: Serum typing, PFGE, REP-PCR, and ERIC-PCR molecular typing and cluster analysis were performed on 150 VP isolates from Liaoning Province in 2018. RESULTS: 118 isolates could be divided into 14 Serotype, and 32 isolates could not be classified. The main serotypes were O3, O1 and O2. The resolution(DI) of PFGE is 0.969, the resolution(DI) of REP-PCR is 0.948, and the resolution(DI) of ERIC-PCR is 0.927. The Serotype O3 group strains are highly similar to the molecular types of O1 group strains. CONCLUSION: In 2018, the epidemic Serotype of clinical VP isolates in Liaoning Province is still O3: K6, and the epidemic serotype of food VP isolates is still O2. The result of PFGE, REP-PCR, and ERIC-PCR typing method are consistent, and the resolution and reproducibility of PFGE typing method are superior to the other two method. The Serotype O3 group is closely related to O1 group.

MIOX inhibits autophagy to regulate the ROS -driven inhibition of STAT3/c-Myc-mediated epithelial-mesenchymal transition in clear cell renal cell carcinoma.

The specific mechanism of clear cell renal cell carcinoma (ccRCC) progression, a pathological type that accounts for the highest proportion of RCC, remains unclear. In this study, bioinformatics analysis of scRNA-seq dataset in ccRCC revealed that MIOX was a gene specifically down-regulated in tumor epithelial cells of ccRCC. Analysis of the TCGA database further validated the association between decreased MIOX mRNA levels and ccRCC malignant phenotype and poor prognosis. Immunohistochemistry indicated the down-regulation of MIOX in ccRCC tissues compared to paired adjacent renal tissues, with further down-regulation of MIOX in the primary tumors of patients with primary metastasis compared to those without metastasis. Also, patients with low expression of MIOX showed shorter metastasis-free survival (MFS) compared to those with high MIOX expression. In vitro results showed that overexpression of MIOX in ccRCC cells inhibited the proliferation, migration and invasion and promoted apoptosis. Mechanistically, up-regulation of MIOX inhibited autophagy to elevate the levels of ROS, and thus suppressed STAT3/c-Myc-mediated epithelial-mesenchymal transition in ccRCC cells. In vivo data further confirmed that increased MIOX expression suppressed the growth and proliferation of RCC cells and reduced the ability of RCC cells to form metastases in the lung. This study demonstrates that MIOX is an important regulatory molecule of ccRCC, which is conducive to understanding the potential molecular mechanism of ccRCC progression.

WDR4 promotes the progression and lymphatic metastasis of bladder cancer via transcriptional down-regulation of ARRB2.

Lymph node (LN) metastasis is one of the key prognostic factors in bladder cancer, but its underlying mechanisms remain unclear. Here, we found that elevated expression of WD repeat domain 4 (WDR4) in bladder cancer correlated with worse prognosis. WDR4 can promote the LN metastasis and proliferation of bladder cancer cells. Mechanistic studies showed that WDR4 can promote the nuclear localization of DEAD-box helicase 20 (DDX20) and act as an adaptor to bind DDX20 and Early growth response 1 (Egr1), thereby inhibiting Egr1-promoted transcriptional expression of arrestin beta 2 (ARRB2) and ultimately contributing to the progression of bladder cancer. Immunohistochemical analysis confirmed that WDR4 expression is also an independent predictor of LN metastasis in bladder cancer. Our results reveal a novel mechanism of LN metastasis and progression in bladder cancer and identify WDR4 as a potential therapeutic target for metastatic bladder cancer.

LINC00926 promotes progression of renal cell carcinoma via regulating miR-30a-5p/SOX4 axis and activating IFNγ-JAK2-STAT1 pathway.

The role of long non-coding RNA (lncRNA) in the progression of renal cell carcinoma (RCC) remains further study. Whether lncRNA may be used to predict the immunotherapy efficacy of RCC is less studied. In this study, LINC00926 was found to be mainly located in cytoplasm by FISH and RNA nuclear-cytoplasmic fractionation. Downregulation of LINC00926 in RCC cell lines inhibited the progression and metastasis of RCC cells. RNA pull-down assay and dual-luciferase reporter assay demonstrated that LINC00926 functioned as miR-30a-5p sponge to facilitate SOX4 expression. LINC00926 overexpression in BALB/c mice enhanced PD-L1 surface expression and resulted in immune escape. Mechanistic investigations showed that LINC00926 competitively bound to Lyn, leading to the inhibition of CBL-mediated ubiquitination and degradation, and stabilized Lyn, contributing to the activation of IFNγ-JAK2-STAT1 signaling pathway. Moreover, LINC00926, together with PD-L1 or PD-1 expression, may predict the overall survival in RCC patients. Therefore, LINC00926 has the potential to be a novel therapeutic target and a biomarker to predict ICB immunotherapy response in RCC.

ROS Scavenging Nanozyme Modulates Immunosuppression for Sensitized Cancer Immunotherapy.

Myeloid-derived suppressor cells (MDSCs) and tumor-associated macrophages (TAMs), two immunosuppressive myeloid components within the tumor microenvironment (TME), represent fundamental barriers in cancer immunotherapy, whereas current nanomedicines rarely exert dual modulatory roles on these cell types simultaneously. Reactive oxygen species (ROS) not only mediates MDSC-induced immunosuppression but also triggers differentiation and polarization of M2-TAMs. Herein, an ROS scavenging nanozyme, Zr-CeO, with enhanced superoxide dismutase- and catalase-like activities for renal tumor growth inhibition is reported. Mechanistically, intracellular ROS scavenging by Zr-CeO significantly attenuates MDSC immunosuppression via dampening the unfolded protein response, hinders M2-TAM polarization through the ERK and STAT3 pathways, but barely affects neoplastic cells and cancer-associated fibroblasts. Furthermore, Zr-CeO enhances the antitumor effect of PD-1 inhibition in murine renal and breast tumor models, accompanied with substantially decreased MDSC recruitment and reprogrammed phenotype of TAMs in the tumor mass. Upon cell isolation, reversed immunosuppressive phenotypes of MDSCs and TAMs are identified. In addition, Zr-CeO alone or combination therapy enhances T lymphocyte infiltration and IFN-γ production within the TME. Collectively, a promising strategy to impair the quantity and function of immunosuppressive myeloid cells and sensitize immunotherapy in both renal and breast cancers is provided.

Small ankyrin 1 (sANK1) promotes docetaxel resistance in castration-resistant prostate cancer cells by enhancing oxidative phosphorylation.

Docetaxel (DTX) plays an important role in treating advanced prostate cancer (PCa). However, nearly all patients receiving DTX therapy ultimately progress to DTX resistance. How to address DTX resistance in PCa remains a key challenge for all urologists. Small ankyrin 1 (sAnk1) is an integral membrane protein in the endoplasmic reticulum. In the present study, we identified that sAnk1 is upregulated in PCa tissues and is positively associated with DTX therapy resistance in PCa. Further investigation demonstrated that overexpression of sAnk1 can significantly increase the DTX-resistant ability of PCa cells in vitro and in vivo. In addition, overexpression of sAnk1 could enhance oxidative phosphorylation (OXPHOS) levels in PCa cells, which was consistent with the higher OXPHOS levels observed in DTX-resistant PCa cells as compared to DTX-sensitive PCa cells. sAnk1 was also found to interact with polypyrimidine-tract-binding protein (PTBP1), an alternative splicing factor, and suppressed PTBP1-mediated alternative splicing of the pyruvate kinase gene (PKM). Thus, overexpression of sAnk1 decreased the ratio of PKM2/PKM1, enhanced the OXPHOS level, and ultimately promoted the resistance of PCa cells to DTX. In summary, our data suggest that sAnk1 enhances DTX resistance in PCa cells.

Tumor-intrinsic RGS1 potentiates checkpoint blockade response via ATF3-IFNGR1 axis.

Background: Non-responsiveness is a major barrier in current cancer immune checkpoint blockade therapies, and the mechanism has not been elucidated yet. Therefore, it is necessary to discover the mechanism and biomarkers of tumor immunotherapeutic resistance. Methods: Bioinformatics analysis was performed based on CD8+ T cell infiltration in multiple tumor databases to screen out genes related to anti-tumor immunity. Associations between Regulator of G-protein signaling 1 (RGS1) and IFNγ-STAT1 signaling, and MHCI antigen presentation pathway were examined by RT-qPCR, western blotting, and flow cytometry. The modulatory mechanisms of RGS1 were investigated via CHIP-qPCR and dual-luciferase assay. The clinical and therapeutic implications of RGS1 were comprehensively investigated using tumor cell lines, mouse models, and clinical samples receiving immunotherapy. Results: RGS1 was identified as the highest gene positively correlated with immunogenicity among RGS family. Inhibition of RGS1 in neoplastic cells dampened anti-tumor immune response and elicited resistance to immunotherapy in both renal and lung murine subcutaneous tumors. Mechanistically, RGS1 enhanced the binding of activating transcription factor 3 (ATF3) to the promoter of interferon gamma receptor 1 (IFNGR1), activated STAT1 and the subsequent expression of IFNγ-inducible genes, especially CXCL9 and MHC class I (MHCI), thereby influenced CD8+ T cell infiltration and antigen presentation and processing. Clinically, lower expression level of RGS1 was associated with resistance of PD1 inhibition therapy and shortened progression-free survival among 21 NSCLC patients receiving immunotherapy. Conclusions: Together, these findings uncover a novel mechanism that elicits immunotherapy resistance and highlight the function of tumor-intrinsic RGS1, which brings new insights for future strategies to sensitize anti-PD1 immunotherapy.

Cancer-associated fibroblasts promote the stemness and progression of renal cell carcinoma via exosomal miR-181d-5p.

The mechanisms underlying the effects of cancer-associated fibroblasts (CAFs) on cancer stemness and tumor progression in renal cell carcinoma (RCC) have not been elucidated yet. In the present study, we found that the enrichment of CAFs was positively associated with tumor progression and cancer stemness in RCC. Further investigation revealed that CAFs could enhance cancer stemness through delivering exosomes to RCC cells, and miR-181d-5p was identified as the critical exosomal miRNA in CAF-secreted exosomes by small RNA sequencing and subsequent screening assays. Mechanistically, exosomal miR-181d-5p transferred from CAFs to RCC cells directly suppressed the expression of ring finger protein 43 (RNF43) and activated Wnt/ß-catenin signaling pathway, thus promoted cancer stemness and tumor progression. Overexpression of RNF43 strongly suppressed stemness properties and the effects could be reverted by miR-181d-5p. Overall, our findings revealed a crucial mechanism by which CAF-secreted exosomal miRNAs to enhance cancer stemness and thus promote RCC progression, suggesting a new avenue based on CAF-secreted miRNAs for more effective targeted therapies.

Allosteric activation of the metabolic enzyme GPD1 inhibits bladder cancer growth via the lysoPC-PAFR-TRPV2 axis.

BACKGROUND: Bladder cancer is the most common malignant tumor of the urinary system. Surgical resection and chemotherapy are the two mainstream treatments for bladder cancer. However, the outcomes are not satisfactory for patients with advanced bladder cancer. There is a need to further explore more effective targeted therapeutic strategies. METHODS: Proteomics were performed to compare protein expression differences between human bladder cancer tissues and adjacent normal tissues. The function of GPD1 on bladder cancer cells were confirmed through in vivo and in vitro assays. Transcriptomics and metabolomics were performed to reveal the underlying mechanisms of GPD1. Virtual screening was used to identify allosteric activator of GPD1. RESULTS: Here, we used proteomics to find that GPD1 expression was at low levels in bladder cancer tissues. Further investigation showed that GPD1 overexpression significantly promoted apoptosis in bladder cancer cells. Based on transcriptomics and metabolomics, GPD1 promotes Ca2+ influx and apoptosis of tumor cells via the lysoPC-PAFR-TRPV2 axis. Finally, we performed a virtual screening to obtain the GPD1 allosteric activator wedelolactone and demonstrated its ability to inhibit bladder tumor growth in vitro and in vivo. CONCLUSIONS: This study suggests that GPD1 may act as a novel tumor suppressor in bladder cancer. Pharmacological activation of GPD1 is a potential therapeutic approach for bladder cancer.

Lysosomal protein transmembrane 5 promotes lung-specific metastasis by regulating BMPR1A lysosomal degradation.

Organotropism during cancer metastasis occurs frequently but the underlying mechanism remains poorly understood. Here, we show that lysosomal protein transmembrane 5 (LAPTM5) promotes lung-specific metastasis in renal cancer. LAPTM5 sustains self-renewal and cancer stem cell-like traits of renal cancer cells by blocking the function of lung-derived bone morphogenetic proteins (BMPs). Mechanistic investigations showed that LAPTM5 recruits WWP2, which binds to the BMP receptor BMPR1A and mediates its lysosomal sorting, ubiquitination and ultimate degradation. BMPR1A expression was restored by the lysosomal inhibitor chloroquine. LAPTM5 expression could also serve as an independent predictor of lung metastasis in renal cancer. Lastly, elevation of LAPTM5 expression in lung metastases is a common phenomenon in multiple cancer types. Our results reveal a molecular mechanism underlying lung-specific metastasis and identify LAPTM5 as a potential therapeutic target for cancers with lung metastasis.

Mass cytometry reveals immune atlas of urothelial carcinoma.

Immunotherapy has emerged as a robust clinical strategy for cancer treatment. PD1/PD-L1 inhibitors have been used as second-line therapy for urothelial carcinoma due to the high tumor mutational burden. Despite the efficacy of the treatment is significant, the response rate is still poor. The tumor immune microenvironment plays a key role in the regulation of immunotherapeutic efficacy. However, a comprehensive understanding of the intricate microenvironment in clinical samples remains unclear. To obtain detailed systematic tumor immune profile, we performed an in-depth immunoassay on 12 human urothelial carcinoma tissue samples and 14 paratumor tissue samples using mass cytometry. Among the large number of cells assayed, we identified 71 T-cell phenotypes, 30 tumor-associated macrophage phenotypes. T cell marker expression profiles showed that almost all T cells in the tumor tissue were in a state of exhaustion. CD38 expression on tumor-associated macrophages (TAMs) was significantly higher than PDL1, and CD38+ TAMs were closely associated with immunosuppression. CD38 may be a more suitable target for immunotherapy in urothelial carcinoma compared to PD1/PDL1. This single-cell analysis of clinical samples expands our insights into the immune microenvironment of urothelial carcinoma and reveals potential biomarkers and targets for immunotherapy development.

circDHTKD1 promotes lymphatic metastasis of bladder cancer by upregulating CXCL5.

Lymph node (LN) metastasis is associated with unfavorable prognosis of bladder cancer (BCa). Although lymphangiogenesis is functionally important in LN metastasis of tumors, the potential mechanism in BCa remains unclear. Here, we clarified a regulatory mechanism of circRNA-mediated lymphangiogenesis and LN metastasis in BCa based on next-generation sequencing data. We revealed that circDHTKD1 was positively associated with LN metastasis and significantly upregulated in BCa. By analyzing the co-expression patterns of circDHTKD1 and differentially expressed mRNAs, we identified that circDHTKD1 facilitated lymphangiogenesis by upregulating CXCL5. Mechanistically, circDHTKD1 directly interacted with miR-149-5p, and antagonized the repression of miR-149-5p on CXCL5. Furthermore, circDHTKD1-induced CXCL5 expression recruited and activated neutrophils, which participated in lymphangiogenesis by secreting VEGF-C. Our study supports circDHTKD1 as a promising diagnostic and therapeutic target for LN metastasis in BCa.

Pan-cancer analysis identifies LMNB1 as a target to redress Th1/Th2 imbalance and enhance PARP inhibitor response in human cancers.

BACKGROUND: Emerging evidence suggests that LMNB1 is involved in the development of multiple cancer types. However, there is no study reporting the potential role of LMNB1 in a systematic pan-cancer manner. METHODS: The gene expression level and potential oncogenic roles of LMNB1 in The Cancer Genome Atlas (TCGA) database were analyzed with Tumor Immune Estimation Resource version 2 (TIMER2.0), Gene Expression Profiling Interactive Analysis version 2 (GEPIA2), UALCAN and Sangerbox tools. Pathway enrichment analysis was carried out to explore the possible mechanism of LMNB1 on tumorigenesis and tumor progression. The therapeutic effects of LMNB1 knockdown combined with PARP inhibition on human cancers were further investigated in vitro. RESULTS: LMNB1 upregulation is generally observed in the tumor tissues of most TCGA cancer types, and is verified in kidney renal clear cell carcinoma using clinical specimens of our institute. High level of LMNB1 expression usually predicts poor overall survival and disease free survival for patients with tumors. Mechanically, LMNB1 level is positively correlated with CD4+ Th2 cell infiltration and DNA homologous recombination repair gene expression. In vitro experiments reveal that targeting LMNB1 has a synergistic effect on prostate cancer with PARP inhibitor treatment. CONCLUSIONS: LMNB1 is a biomarker of CD4+ Th2 cell infiltration and DNA homologous recombination repair in human cancers. Blockage of LMNB1 combined with PARP inhibitor treatment could be a promising therapeutic strategy for patients with cancers.

SOX9 in prostate cancer is upregulated by cancer-associated fibroblasts to promote tumor progression through HGF/c-Met-FRA1 signaling.

Transcription factor SOX9 was a biomarker for prostate cancer (Pca) with poor prognosis. Nevertheless, the regulatory mechanism underlying SOX9 upregulation still remains unclear. Several cytokines have been reported to be involved in the regulation of SOX9, suggesting that cancer-associated fibroblasts (CAFs), one of the main sources of secreted factors in the tumor microenvironment (TME), may play a role in regulating SOX9 expression. Herein, an in vitro model of paracrine interaction between primary CAFs and Pca cells was applied to investigate the molecular mechanism of SOX9 upregulation during Pca progression. The regulatory axis was validated by in vivo experiments and The Cancer Genome Atlas data. Conditional medium of CAFs (CAF-CM) upregulated the expression of SOX9, which was mutually proved to be essential for CAF-induced tumor progression. Further analysis showed that hepatocyte growth factor (HGF) secreted by CAFs was responsible for SOX9 elevation in Pca cells, via the activation of c-Met signaling. Mechanistically, HGF/c-Met signaling specifically activated MEK1/2-ERK1/2 pathway, which induced phosphorylation and upregulation of FRA1, which then transcriptionally upregulated SOX9 by binding to the promoter of SOX9 gene. Moreover, we identified that HGF/c-Met-ERK1/2-FRA1-SOX9 axis was relatively conserved between human and mouse species by validating in mouse Pca cells. Our results reveal a novel insight into the molecular mechanism that SOX9 in Pca cells is promoted by CAFs through HGF/c-Met-ERK1/2-FRA1 axis. Furthermore, SOX9 may serve as an alternative marker for the activated HGF/c-Met signaling to enroll the optimal Pca patients for HGF/c-Met inhibition treatment, since it is much more stable and easier to detect.

Comparison of gemcitabine and anthracycline antibiotics in prevention of superficial bladder cancer recurrence.

BACKGROUND: Because of the failure, shortage and related toxicities of Bacillus Calmette-Guérin (BCG), the other intravesical chemotherapy drugs are also widely used in clinical application. Gemcitabine and anthracycline antibiotics (epirubicin and pirarubicin) are widely used as first-line or salvage therapy, but which drug is better is less discussed. METHODS: A total of 124 primary NMIBC patients administered intravesical therapy after transurethral resection of bladder tumor (TURBT) at Nanjing Drum Tower hospital from January 1996 to July 2018. After TURBT, all patients accepted standard intravesical chemotherapy. Recurrence was defined as the occurrence of a new tumor in the bladder. Progression was defined as confirmed tumor invading muscular layer. Treatment failure was defined as need for radical cystectomy (RC), systemic chemotherapy and radiation therapy. RESULTS: Of the 124 patients who underwent intravesical chemotherapy, 84 patients were given gemcitabine, 40 patients were given epirubicin or pirarubicin, with mean follow-up times (mean ± SD) of (34.8 ± 17.9) and (35.9 ± 22.1) months respectively. The clinical and pathological features of patients show no difference between two groups. Recurrence rate of patients given gemcitabine was 8.33% (7 out of 84), the recurrence rate was 45% (18 out of 40) for epirubicin or pirarubicin (P < 0.0001). The progression rates of gemcitabine, anthracycline antibiotics groups were 2.38% (2 out of 84) and 20% (8 out of 40), respectively (P < 0.001). The rate of treatment failure is 8.33% (7 out of 84) and 25% (10 out of 40), respectively (P = 0.012). Gemcitabine intravesical chemotherapy group was significantly related to a lower rate of recurrence (HR = 0.165, 95% CI 0.069-0.397, P = 0.000), progression (HR = 0.160, 95% CI 0.032-0.799, P = 0.026) and treatment failure (HR = 0.260, 95% CI 0.078-0.867, P = 0.028). CONCLUSION: In conclusion, gemcitabine intravesical chemotherapy group was significantly related to a lower rate of recurrence, progression and treatment failure. Gemcitabine could be considered as a choice for these patients who are not suitable for BCG.

Astaxanthin protects against renal fibrosis through inhibiting myofibroblast activation and promoting CD8+ T cell recruitment.

BACKGROUND: Renal fibrosis is a common pathological hallmark of chronic kidney disease, and no effective treatment is clinically available to manage its progression. Astaxanthin was recently found to be anti-fibrotic, but its effect on renal fibrosis remains unclear. METHODS: C57BL/6J mice were subjected to unilateral ureteral obstruction and intragastrically administered astaxanthin. Histopathology and immunohistochemistry were performed to evaluate renal fibrosis. Flow cytometry was used to examine lymphocyte accumulation in the fibrotic kidneys. Western blotting, real-time qPCR, and immunofluorescence were performed to cover the underlying mechanism concerning astaxanthin treatment during renal fibrosis. RESULTS: Oral administration of astaxanthin effectively alleviates renal fibrosis in mice. In vitro, astaxanthin inhibited fibroblast activation by modulating Smad2, Akt and STAT3 pathways and suppressed epithelial-to-mesenchymal transition in renal tubular epithelial cells through Smad2, snail, and ß-catenin. Moreover, astaxanthin significantly induced the rapid accumulation of CD8+ T cells in fibrotic kidneys, which was accompanied by elevated expression of IFN-γ. Accordingly, the depletion of CD8+ T cells strongly diminished the protective effect of astaxanthin. Further investigation showed that astaxanthin increased the population of CD8+ T cells by upregulating the expression of CCL5 in macrophages. CONCLUSIONS: These findings highlight the beneficial effect of astaxanthin on fibroblast activation, epithelial-to-mesenchymal transition, and CD8+ T cell recruitment during renal fibrosis. GENERAL SIGNIFICANCE: These data indicate that astaxanthin could serve as a therapeutic strategy to treat renal fibrotic conditions.