Association of PM2.5 exposure in early pregnancy and maternal liver function: A retrospective cohort study in Shenzhen, China.

OBJECTIVE: Studies have shown that fine particulate matter (PM2.5) has adverse effects on the liver function, but epidemiological evidence is limited, especially regarding pregnant women. This study aims to investigate the association between PM2.5 exposure in early pregnancy and maternal liver function during pregnancy. METHODS: This retrospective cohort study included 13,342 pregnant participants. PM2.5 and Ozone (O3) exposure level, mean temperature, and relative humidity for each participant were assessed according to their residential address. The levels of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and total bilirubin (TBIL) were measured during the second and third trimesters. Data on PM2.5 and O3 exposure level were sourced from Tracking Air Pollution in China (TAP), while the mean temperature and relative humidity were obtained from the ERA5 dataset. The Generalized Additive Model (GAM) was used to analyze the associations between PM2.5 exposure and maternal liver function during pregnancy, adjusting for potential confounding factors. RESULTS: According to the results, each 10 µg/m3 increase in PM2.5 was associated with an increase of 3.57% (95% CI: 0.29%, 6.96%) in ALT and 4.25% (95% CI: 2.33%, 6.21%) in TBIL during the second trimester and 4.51% (95% CI: 2.59%, 6.47%) in TBIL during the third trimester, respectively. After adjusting for O3, these associations remained significant, and the effect of PM2.5 on ALT during the second trimester was further strengthened. No significant association observed between PM2.5 and AST. CONCLUSIONS: PM2.5 exposure in early pregnancy is associated with increasement of maternal ALT and TBIL, suggesting that PM2.5 exposure may have an adverse effect on maternal liver function. Although this finding indicates an association between PM2.5 exposure and maternal liver function, more research is needed to confirm our findings and explore the underlying biological mechanisms.

The OGT-c-Myc-PDK2 axis rewires the TCA cycle and promotes colorectal tumor growth.

Deregulated glucose metabolism termed the "Warburg effect" is a fundamental feature of cancers, including the colorectal cancer. This is typically characterized with an increased rate of glycolysis, and a concomitant reduced rate of the tricarboxylic acid (TCA) cycle metabolism as compared to the normal cells. How the TCA cycle is manipulated in cancer cells remains unknown. Here, we show that O-linked N-acetylglucosamine (O-GlcNAc) regulates the TCA cycle in colorectal cancer cells. Depletion of OGT, the sole transferase of O-GlcNAc, significantly increases the TCA cycle metabolism in colorectal cancer cells. Mechanistically, OGT-catalyzed O-GlcNAc modification of c-Myc at serine 415 (S415) increases c-Myc stability, which transcriptionally upregulates the expression of pyruvate dehydrogenase kinase 2 (PDK2). PDK2 phosphorylates pyruvate dehydrogenase (PDH) to inhibit the activity of mitochondrial pyruvate dehydrogenase complex, which reduces mitochondrial pyruvate metabolism, suppresses reactive oxygen species production, and promotes xenograft tumor growth. Furthermore, c-Myc S415 glycosylation levels positively correlate with PDK2 expression levels in clinical colorectal tumor tissues. This study highlights the OGT-c-Myc-PDK2 axis as a key mechanism linking oncoprotein activation with deregulated glucose metabolism in colorectal cancer.

A novel EIF3C-related CD8+ T-cell signature in predicting prognosis and immunotherapy response of nasopharyngeal carcinoma.

PURPOSE: At present, dysfunctional CD8+ T-cells in the nasopharyngeal carcinoma (NPC) tumor immune microenvironment (TIME) have caused unsatisfactory immunotherapeutic effects, such as a low response rate of anti-PD-L1 therapy. Therefore, there is an urgent need to identify reliable markers capable of accurately predicting immunotherapy efficacy. METHODS: Utilizing various algorithms for immune-infiltration evaluation, we explored the role of EIF3C in the TIME. We next found the influence of EIF3C expression on NPC based on functional analyses and RNA sequencing. By performing correlation and univariate Cox analyses of CD8+ Tcell markers from scRNA-seq data, we identified four signatures, which were then used in conjunction with the lasso algorithm to determine corresponding coefficients in the resulting EIF3C-related CD8+ T-cell signature (ETS). We subsequently evaluated the prognostic value of ETS using univariate and multivariate Cox regression analyses, Kaplan-Meier curves, and the area under the receiver operating characteristic curve (AUROC). RESULTS: Our results demonstrate a significant relationship between low expression of EIF3C and high levels of CD8+ T-cell infiltration in the TIME, as well as a correlation between EIF3C expression and progression of NPC. Based on the expression levels of four EIF3C-related CD8+ T-cell marker genes, we constructed the ETS predictive model for NPC prognosis, which demonstrated success in validation. Notably, our model can also serve as an accurate indicator for detecting immunotherapy response. CONCLUSION: Our findings suggest that EIF3C plays a significant role in NPC progression and immune modulation, particularly in CD8+ T-cell infiltration. Furthermore, the ETS model holds promise as both a prognostic predictor for NPC patients and a tool for adjusting individualized immunotherapy strategies.

Ochratoxin A detoxification potentials of basil, chan, and chia seeds.

The most toxic of the ochratoxins is ochratoxin A (OTA), which is primarily produced by species of Aspergillus and Penicillium that can be found in maize, wheat, coffee, red wine, and various grains. OTA induces immunotoxicity, nephrotoxicity, hepatotoxicity, teratogenicity, and carcinogenicity in both animals and humans. Thus, there is a need to identify mycotoxin detoxification agents that can effectively decontaminate OTA. Seeds of basil (Ocimum basilicum L.), chan (Hyptis suaveolens L.), and chia (Salvia hispanica L.) are functional foods capable of eliminating harmful substances. Despite this potential, the impact of these seeds on OTA detoxification remains unclear. This study reveals that milled basil, chan, and chia seeds adsorb significant levels of OTA, with chia demonstrating the highest adsorption capacity, followed by chan and basil seeds showing the least efficiency. Furthermore, milled basil, chan, and chia seeds effectively reduced OTA residues in artificial gastric and intestinal fluids, where they achieved up to 93% OTA adsorption in the former. In addition, these milled seeds were able to remove OTAs from canned, drip, and instant coffee. This study is the first to report the OTA elimination potential of basil, chan, and chia seeds.

Sialic Acid-Modified O-GlcNAc Transferase Inhibitor Liposome Presents Antitumor Effect in Hepatocellular Carcinoma.

O-linked-N-acetylglucosaminylation (O-GlcNAcylation) plays a key role in hepatocellular carcinoma (HCC) development, and the inhibition of O-GlcNAcylation has therapeutic potential. To decrease the systemic adverse events and increase targeting, we used sialic acid (SA)-decorated liposomes loaded with OSMI-1, an inhibitor of the O-GlcNAcylation, to further improve the anti-HCC effect. Fifty pairs of HCC tissue samples and the cancer genome atlas database were used to analyze the expression of O-GlcNAc transferase (OGT) and its effects on prognosis and immune cell infiltration. OSMI-1 cells were treated with SA and liposomes. Western blotting, immunofluorescence, cell proliferation assay, flow cytometry, enzyme-linked immunosorbent assay, immunohistochemistry, and tumorigenicity assays were used to investigate the antitumor effect of SA-modified OSMI-1 liposomes in vitro and in vivo. OGT was highly expressed in HCC tissues, negatively correlated with the degree of tumor infiltration of CD8+ and CD4+T cells and prognosis, and positively correlated with the degree of Treg cell infiltration. SA-modified OSMI-1 liposome (OSMI-1-SAL) was synthesized with stable hydrodynamic size distribution. Both in vitro and in vivo, OSMI-1-SAL exhibited satisfactory biosafety and rapid uptake by HCC cells. Compared to free OSMI-1, OSMI-1-SAL had a stronger capacity for suppressing the proliferation and promoting the apoptosis of HCC cells. Moreover, OSMI-1-SAL effectively inhibited tumor initiation and development in mice. OSMI-1-SAL also promoted the release of damage-associated molecular patterns, including anticalreticulin, high-mobility-group protein B1, and adenosine triphosphate, from HCC cells and further promoted the activation and proliferation of the CD8+ and CD4+T cells. In conclusion, the OSMI-1-SAL synthesized in this study can target HCC cells, inhibit tumor proliferation, induce tumor immunogenic cell death, enhance tumor immunogenicity, and promote antitumor immune responses, which has the potential for clinical application in the future.

NRF2, a Superstar of Ferroptosis.

Ferroptosis is an iron-dependent and lipid peroxidation-driven cell death cascade, occurring when there is an imbalance of redox homeostasis in the cell. Nuclear factor erythroid 2-related factor 2 (NFE2L2, also known as NRF2) is key for cellular antioxidant responses, which promotes downstream genes transcription by binding to their antioxidant response elements (AREs). Numerous studies suggest that NRF2 assumes an extremely important role in the regulation of ferroptosis, for its various functions in iron, lipid, and amino acid metabolism, and so on. Many pathological states are relevant to ferroptosis. Abnormal suppression of ferroptosis is found in many cases of cancer, promoting their progression and metastasis. While during tissue damages, ferroptosis is recurrently promoted, resulting in a large number of cell deaths and even dysfunctions of the corresponding organs. Therefore, targeting NRF2-related signaling pathways, to induce or inhibit ferroptosis, has become a great potential therapy for combating cancers, as well as preventing neurodegenerative and ischemic diseases. In this review, a brief overview of the research process of ferroptosis over the past decade will be presented. In particular, the mechanisms of ferroptosis and a focus on the regulation of ferroptosis by NRF2 will be discussed. Finally, the review will briefly list some clinical applications of targeting the NRF2 signaling pathway in the treatment of diseases.

O-GlcNAcylation promotes tumor immune evasion by inhibiting PD-L1 lysosomal degradation.

Programmed-death ligand 1 (PD-L1) and its receptor programmed cell death 1 (PD-1) mediate T cell-dependent immunity against tumors. The abundance of cell surface PD-L1 is a key determinant of the efficacy of immune checkpoint blockade therapy targeting PD-L1. However, the regulation of cell surface PD-L1 is still poorly understood. Here, we show that lysosomal degradation of PD-L1 is regulated by O-linked N-acetylglucosamine (O-GlcNAc) during the intracellular trafficking pathway. O-GlcNAc modifies the hepatocyte growth factor-regulated tyrosine kinase substrate (HGS), a key component of the endosomal sorting machinery, and subsequently inhibits its interaction with intracellular PD-L1, leading to impaired lysosomal degradation of PD-L1. O-GlcNAc inhibition activates T cell-mediated antitumor immunity in vitro and in immune-competent mice in a manner dependent on HGS glycosylation. Combination of O-GlcNAc inhibition with PD-L1 antibody synergistically promotes antitumor immune response. We also designed a competitive peptide inhibitor of HGS glycosylation that decreases PD-L1 expression and enhances T cell-mediated immunity against tumor cells. Collectively, our study reveals a link between O-GlcNAc and tumor immune evasion, and suggests strategies for improving PD-L1-mediated immune checkpoint blockade therapy.

O-GlcNAcylation regulates epidermal growth factor receptor intracellular trafficking and signaling.

SignificanceEpidermal growth factor receptor (EGFR) is one of the most important membrane receptors that transduce growth signals into cells to sustain cell growth, proliferation, and survival. EGFR signal termination is initiated by EGFR internalization, followed by trafficking through endosomes, and degradation in lysosomes. How this process is regulated is still poorly understood. Here, we show that hepatocyte growth factor regulated tyrosine kinase substrate (HGS), a key protein in the EGFR trafficking pathway, is dynamically modified by a single sugar N-acetylglucosamine. This modification inhibits EGFR trafficking from endosomes to lysosomes, leading to the accumulation of EGFR and prolonged signaling. This study provides an important insight into diseases with aberrant growth factor signaling, such as cancer, obesity, and diabetes.

SNHG16 promotes hepatocellular carcinoma development via activating ECM receptor interaction pathway.

BACKGROUND: Accumulating data have suggested that long non-coding RNAs (lncRNAs) play important roles in regulating tumor cell growth. This study was designed to investigate the role of SNHG16 in hepatocellular carcinoma (HCC). METHODS: SNHG16 expression was detected with real-time polymerase chain reaction (PCR). The cutoff value of SNHG16 for tumor-free survival (TFS) was determined with receiver operating characteristic curve analysis. Small interfering RNA was used to inhibit the expression of SNHG16 in HCC cell lines. The biologic behavior of HCC cell was determined with cell viability assay and Transwell assay in vitro. The potential predictive value of SNHG16 on prognosis was analyzed by Kaplan-Meier curves and Cox proportional hazards regression model. RESULTS: SNHG16 expression was upregulated in tumor tissues and HCC cell lines. High expression of SNHG16 was associated with tumor recurrence and poor prognosis after surgery. Multivariate analysis revealed that SNHG16 was an independent prognostic factor for poor recurrence-free survival. Moreover, inhibition of SNHG16 in HepG2, Hep3B, and BEL-7402 cells significantly reduced cell invasiveness and proliferation. Mechanistic analyses indicated that the ECM-receptor interaction pathway was remarkably activated by SNHG16. CONCLUSIONS: SNHG16 might be a promising biomarker for predicting tumor recurrence in HCC patients after surgery and a potential therapeutic target for HCC.

SMYD2 Promotes Hepatocellular Carcinoma Progression by Reprogramming Glutamine Metabolism via c-Myc/GLS1 Axis.

Metabolic reprogramming, such as alterations in glutamine metabolism or glycolysis, is the hallmark of hepatocellular carcinoma (HCC). However, the underlying mechanisms are still incompletely elucidated. Previous studies have identified that methyltransferase SET and MYND domain-containing protein 2(SMYD2) is responsible for the pathogenesis of numerous types of cancer. Here, we innovatively uncover how SMYD2 regulates glutamine metabolism in HCC cells and promotes HCC progression. We identified that SMYD2 expression is upregulated in HCC tissues, which correlates with unfavorable clinical outcomes. Our in vitro and in vivo results showed that the depletion of SMYD2 inhibits HCC cell growth. Mechanistically, c-Myc methylation by SMYD2 increases its protein stability through the ubiquitin-proteasome system. We showed SMYD2 depletion destabilized c-Myc protein by increasing the conjugated K48-linked polyubiquitin chain. SMYD2 increased c-Myc expression and further upregulated glutaminase1 (GLS1), a crucial enzyme that catalyzes the conversion of glutamine to glutamic acid, in HCC cells. GLS1 plays an important role in SMYD2-mediated HCC progression and glutamine metabolism regulation. The knockdown of SMYD2 inhibited glutamine metabolism in HCC cells and overcame their chemoresistance to sorafenib. Collectively, our findings demonstrated a novel mechanism of how SMYD2 promotes HCC progression by regulating glutamine metabolism through the c-Myc/GLS1signaling, implicating the therapeutic potential of targeting SMYD2 in HCC patients.

One-Step Enzymatic Labeling Reveals a Critical Role of O-GlcNAcylation in Cell-Cycle Progression and DNA Damage Response.

O-linked N-acetylglucosamine (O-GlcNAcylation) is a ubiquitous post-translational modification of proteins that is essential for cell function. Perturbation of O-GlcNAcylation leads to altered cell-cycle progression and DNA damage response. However, the underlying mechanisms are poorly understood. Here, we develop a highly sensitive one-step enzymatic strategy for capture and profiling O-GlcNAcylated proteins in cells. Using this strategy, we discover that flap endonuclease 1 (FEN1), an essential enzyme in DNA synthesis, is a novel substrate for O-GlcNAcylation. FEN1 O-GlcNAcylation is dynamically regulated during the cell cycle. O-GlcNAcylation at the serine 352 of FEN1 disrupts its interaction with Proliferating Cell Nuclear Antigen (PCNA) at the replication foci, and leads to altered cell cycle, defects in DNA replication, accumulation of DNA damage, and enhanced sensitivity to DNA damage agents. Thus, our study provides a sensitive method for profiling O-GlcNAcylated proteins, and reveals an unknown mechanism of O-GlcNAcylation in regulating cell cycle progression and DNA damage response.

Experience With Anti-PD-1 Antibody, Camrelizumab, Monotherapy for Biliary Tract Cancer Patients and Literature Review.

BACKGROUND: Novel immunotherapy is one of the options for advanced biliary tract cancer (BTC) patients who are traditionally intolerant to chemotherapy. However, clinical evidence for single immunotherapy with pembrolizumab or nivolumab is limited. The present study assessed the safety and efficiency of the anti-PD-1 antibody, camrelizumab, as monotherapy in patients with unresectable or recurrent BTC. METHODS: A retrospective evaluation was conducted among 4 patients with BTC, including 2 with intrahepatic cholangiocellular carcinoma (ICC), one with extrahepatic bile duct cancer, and one with gallbladder cancer. The patients with unresectable or recurrent BTC were refractory or intolerant to gemcitabine plus cisplatin treatment regimens and received at least one intravenous dose (3 mg/kg) of camrelizumab monotherapy every 3 weeks. Gene sequencing analysis was also performed for biomarker screening. Patient reaction was evaluated according to modified response evaluation criteria in solid tumor (RECIST) version 1.1, progression-free survival (PFS), and toxicity. RESULTS: In this cohort, 1 patient with recurrent ICC had a positive response to treatment, with a substantial tumor size reduction in liver and lung metastases verified using a radiological test after receiving 3 cycles of camrelizumab. The PFS was 4.9 months. The remaining 3 patients showed no response to treatment and experienced disease progression. RNA sequence analysis didn't found high expression on genes that related to PD-L1, microsatellite instability, tumor mutation burden, and DNA mismatch repair in these patients. Grade 3 treatment-related adverse event was observed in 1 patient. CONCLUSIONS: Anti-PD-1 antibody camrelizumab had a manageable safety profile in patients with advanced BTC. This initial assessment of camrelizumab monotherapy provides effective evidence for patients with refractory BTC in biomarker-unselected patients.

Long non-coding RNA00844 inhibits MAPK signaling to suppress the progression of hepatocellular carcinoma by targeting AZGP1.

BACKGROUND: Previous data have confirmed that disordered long non-coding ribonucleic acid (lncRNA) expression is evident in many cancers and is correlated with tumor progression. The present study aimed to investigate the function of long non-coding RNA00844 (LINC00844) in hepatocellular carcinoma (HCC). METHODS: The expression levels of target genes were detected with real-time polymerase chain reaction (PCR) and western blotting. The biologic function of HCC cells was determined with cell viability assay, colony formation assay, cell cycle analysis, apoptosis detection, and Transwell migration assay in vitro. Tumorigenesis was performed with cell injection in vivo. The relationship between LINC00844 and survival outcomes was determined with the Cox proportional hazards model. A RNA precipitation assay was conducted to reveal the types of LINC00844 that potentially bind with proteins. RESULTS: LINC00844 was found to be significantly decreased in HCC tissue and was correlated with poor tumor characteristics, such as portal vein invasion, high α-fetoprotein (AFP), and a high rate of tumor recurrence. Exotic LINC00844 expression in HCC cell lines significantly suppressed proliferation and migration, as well as invasiveness, whereas LINC00844 deletion had the opposite effect. LINC00844 overexpression significantly inhibited HCC tumorigenesis in vivo. Mechanistic analyses indicated that the mitogen-activated protein kinase (MAPK) signaling pathway was remarkably inactivated by LINC00844. Furthermore, the immunoprecipitation assay verified that LINC00844 can bind to zinc-alpha-2-glycoprotein (AZGP1) and interfere with its translocation. LINC00844 can also promote AZGP1 expression, leading to the suppression of the transforming growth factor-ß1 (TGF-ß1)-extracellular signal-regulated kinase (ERK) pathway. CONCLUSIONS: LINC00844 is a novel anti-oncogene in the development of HCC and a potentially promising therapeutic target in HCC.

Associations between obesity and metabolic health with nonalcoholic fatty liver disease in elderly Chinese.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is closely associated with obesity. However, this association could be influenced by the coexisting metabolic abnormalities. This study aimed to investigate the role of obesity and metabolic abnormalities in NAFLD among elderly Chinese. METHODS: A cross-sectional study was performed among elderly residents who took their annual health checkups during 2016 in Keqiao District, Shaoxing, China. RESULTS: A total of 3359 elderly adults were retrospectively included in this study. The overall prevalence of NAFLD was 28.7%. The prevalence of NAFLD were 7.14%, 27.92%, 34.80%, and 61.02% in participants with metabolically healthy normal weight (MHNW), metabolically abnormal normal weight (MANW), metabolically healthy obese (MHO), and metabolically abnormal obese (MAO), respectively. NAFLD patients in MHO group had more unfavorable metabolic profiles than those in MHNW group. Logistic regression analysis showed that sex, body mass index (BMI), fasting blood glucose, and serum uric acid were the risk factors of NAFLD. CONCLUSIONS: Both obesity and metabolic health were significantly associated with NAFLD in elderly Chinese. Screening for obesity and other metabolic abnormalities should be routinely performed for early risk stratification of NAFLD.

YAP promotes multi-drug resistance and inhibits autophagy-related cell death in hepatocellular carcinoma via the RAC1-ROS-mTOR pathway.

BACKGROUND: Multi-drug resistance is the major cause of chemotherapy failure in hepatocellular carcinoma (HCC). YAP, a critical effector of the Hippo pathway, has been shown to contribute to the progression, metastasis and invasion of cancers. However, the potential role of YAP in mediating drug resistance remains obscure. METHODS: RT-qPCR and western blot were used to assess YAP expression in HCC cell lines. CCK-8 assays, flow cytometry, a xenograft tumour model, immunochemistry and GFP-mRFP-LC3 fusion proteins were utilized to evaluate the effect of YAP on multi-drug resistance, intracellular ROS production and the autophagy of HCC cells in vitro and in vivo. Autophagy inhibitor and rescue experiments were carried out to elucidate the mechanism by which YAP promotes chemoresistance in HCC cells. RESULTS: We found that BEL/FU, a typical HCC cell line with chemoresistance, exhibited overexpression of YAP. Moreover, the inhibition of YAP by shRNA or verteporfin conferred the sensitivity of BEL/FU cells to chemotherapeutic agents through autophagy-related cell death in vitro and in vivo. Mechanistically, YAP silencing significantly enhanced autophagic flux by increasing RAC1-driven ROS, which contributed to the inactivation of mTOR in HCC cells. In addition, the antagonist of autophagy reversed the enhanced effect of YAP silencing on cell death under treatment with chemotherapeutic agents. CONCLUSION: Our findings suggested that YAP upregulation endowed HCC cells with multi-drug resistance via the RAC1-ROS-mTOR pathway, resulting in the repression of autophagy-related cell death. The blockade of YAP may serve as a promising novel therapeutic strategy for overcoming chemoresistance in HCC.

Lower mean platelet volume is a risk indicator of hepatocellular carcinoma recurrence following liver transplantation.

BACKGROUND: Lower mean platelet volume (MPV) is an indicator of platelet activity in the setting of tumor development. This study was to assess the relationship between preoperative MPV and survival outcomes of patients with hepatocellular carcinoma (HCC) following liver transplantation (LT). METHODS: The demographic and clinical characteristics of 304 HCC patients following LT were retrieved from an LT database. All the patients were divided into the normal and lower MPV groups according to the median MPV. The factors were first analyzed using a Kaplan-Meier survival analysis, then the factors with P < 0.10 were selected for multivariate Cox regression analysis and were used to define the independent risk factors for poor prognosis. RESULTS: The 1-, 3-, and 5-year tumor free survival was 95.34%, 74.67% and 69.29% in the normal MPV group, respectively, and 95.40%, 59.97% and 42.94% in the lower MPV group, respectively (P < 0.01). No significant difference was observed in post-LT complications between the normal and lower MPV groups. Portal vein tumor thrombosis (PVTT) [hazard ratio (HR = 2.24; 95% confidence interval: 1.46-3.43; P < 0.01) and lower MPV (HR = 1.58; 95% confidence interval: 1.05-2.36; P = 0.03) were identified as independent prognostic risk factors for recipient survival. CONCLUSION: Preoperative lower MPV is a risk indicator of HCC patients survival outcomes after LT.

Enzyme-responsive multifunctional peptide coating of gold nanorods improves tumor targeting and photothermal therapy efficacy.

It is well known that stealth coating effectively extends the circulation lifetime of nanomaterials in blood, which favors systemic delivery but also limits their cellular internalization and in turn prevents efficient tumor-targeting and accumulation. In this study, we address this dilemma by developing an enzyme-responsive zwitterionic stealth peptide coating capable of responding to matrix metalloproteinase-9 (MMP-9) which is overexpressed in tumor microenvironment. The peptide consists of a cell-penetrating Tat sequence, an MMP-9 cleavable sequence, and a zwitterionic antifouling sequence. Using this coating to protect photothermal gold nanorods (AuNRs), we found that responsive AuNRs showed both satisfactory systemic circulation lifetime and significantly enhanced cellular uptake in tumors, resulting in clearly improved photothermal therapeutic efficacy in mouse models. These results suggest that multifunctional peptide coated AuNRs sensitive to MMP-9 are promising nanomaterials, conferring both extended systemic circulation and enhanced tumor tissue accumulation, for more specific and efficient tumor therapy. STATEMENT OF SIGNIFICANCE: It is well known that stealth coating effectively extends the circulation lifetime of nanomaterials in blood, which favors systemic delivery but also limits their cellular internalization and in turn prevents efficient tumor-targeting and accumulation. In this study, we address this dilemma by developing an enzyme-responsive zwitterionic stealth peptide coating capable of responding to matrix metalloproteinase-9 (MMP-9) which is overexpressed in tumor microenvironment. The peptide consists of a cell-penetrating Tat sequence, an MMP-9 cleavable sequence, and a zwitterionic antifouling sequence. Using this coating to protect photothermal gold nanorods (AuNRs), we found that responsive AuNRs showed both satisfactory systemic circulation lifetime and significantly enhanced cellular uptake in tumors, resulting in clearly improved photothermal therapeutic efficacy in mouse models.