Algicidal activity synchronized with nitrogen removal by actinomycetes: Algicidal mechanism, stress response of algal cells, denitrification performance, and indigenous bacterial community co-occurrence.

The harmful algal blooms (HABs) can damage the ecological equilibrium of aquatic ecosystems and threaten human health. The bio-degradation of algal by algicidal bacteria is an environmentally friendly and economical approach to control HABs. This study applied an aerobic denitrification synchronization algicidal strain Streptomyces sp. LJH-12-1 (L1) to control HABs. The cell-free filtrate of the strain L1 showed a great algolytic effect on bloom-forming cyanobacterium, Microcystis aeruginosa (M. aeruginosa). The optimal algicidal property of strain L1 was indirect light-dependent algicidal with an algicidal rate of 85.0%. The functional metabolism, light-trapping, light-transfer efficiency, the content of pigments, and inhibition of photosynthesis of M. aeruginosa decreased after the addition of the supernatant of the strain L1 due to oxidative stress. Moreover, 96.05% nitrate removal rate synchronized with algicidal activity was achieved with the strain L1. The relative abundance of N cycling functional genes significantly increased during the strain L1 effect on M. aeruginosa. The algicidal efficiency of the strain L1 in the raw water was 76.70% with nitrate removal efficiency of 81.4%. Overall, this study provides a novel route to apply bacterial strain with the property of denitrification coupled with algicidal activity in treating micro-polluted water bodies.

Aged-Signal-Eliciting Nanoparticles Stimulated Macrophage-Mediated Programmed Removal of Inflammatory Neutrophils.

Excessive infiltration of activated neutrophils is regarded as a predominant cause of tissue injury in neutrophilic inflammation. Although programmed cell death like apoptosis maintains the homeostasis of activated neutrophils, this process is disrupted by an abnormal inflammatory response. Unlike endogenous calreticulin exposed during apoptosis, exogenous calreticulin acts as an "aged" signal and initiates premature macrophage-mediated programmed cell removal (PrCR), which is independent of apoptosis. Here, we report a nano-mediated strategy to stimulate the precise clearance of activated neutrophils initiated with artificial aged signal and alleviated inflammation. Polymeric nanoparticles PC@PLGA were fabricated by cloaking poly(lactic-co-glycolic acid) (PLGA) with a hybrid membrane derived from platelet-derived extracellular vesicles (PEVs, denoted by P) and the calreticulin-expressed membrane obtained from doxorubicin-treated cells (denoted by C). P-selectin in PEVs favors PC@PLGA to anchor activated neutrophils, while calreticulin mimics exogenous "aged" signal secreted by macrophages to trigger PrCR. We showed that PC@PLGA specifically targeted activated neutrophils and misled macrophages to recognize them as "aged" neutrophils and then initiated premature PrCR and prevented proinflammatory response and tissue damage in a mouse model of acute lung injury and severe acute pancreatitis. The collective findings indicate the efficiency of specific elimination of activated neutrophils with exogenous aged signal in improving inflammation therapy.

In Situ Albumin-Hitchhiking NIR-II Probes for Accurate Detection of Micrometastases.

Tumor metastasis remains the primary cause of treatment failure in cancer patients, and the high-sensitivity preoperative and intraoperative detection of occult micrometastases continues to pose a notorious challenge. Therefore, we have designed an in situ albumin-hitchhiking near-infrared window II (NIR-II) fluorescence probe, IR1080, for the precise detection of micrometastases and subsequent fluorescence image-guided surgery. IR1080 rapidly covalently conjugates with albumin in plasma, resulting in a stronger fluorescence brightness upon binding. Moreover, the albumin-hitchhiked IR1080 has a high affinity for secreted protein acidic and rich in cysteine (SPARC), an albumin-binding protein that is overexpressed in micrometastases. The interaction between SPARC and IR1080-hitchhiked albumin enhances IR1080's capacity to track and anchor micrometastases, leading to a high detection rate and margin delineation ability, as well as a high tumor-to-normal tissue ratio. Therefore, IR1080 represents a highly efficient strategy for the diagnosis and image-guided resection surgery of micrometastases.

Prediction model based on radiomics and clinical features for preoperative lymphovascular invasion in gastric cancer patients.

Background: We explored whether a model based on contrast-enhanced computed tomography radiomics features and clinicopathological factors can evaluate preoperative lymphovascular invasion (LVI) in patients with gastric cancer (GC) with Lauren classification. Methods: Based on clinical and radiomic characteristics, we established three models: Clinical + Arterial phase_Radcore, Clinical + Venous phase_Radcore and a combined model. The relationship between Lauren classification and LVI was analyzed using a histogram. Results: We retrospectively analyzed 495 patients with GC. The areas under the curve of the combined model were 0.8629 and 0.8343 in the training and testing datasets, respectively. The combined model showed a superior performance to the other models. Conclusion: CECT-based radiomics models can effectively predict preoperative LVI in GC patients with Lauren classification.

A new nomogram for assessing complete response (CR) in gastric diffuse large B-cell lymphoma (DLBCL) patients after chemotherapy.

PURPOSE: Achieving complete response (CR) after first-line chemotherapy in gastric DLBCL patients often results in longer disease-free survival. We explored whether a model based on imaging features combined with clinicopathological factors could assess the CR to chemotherapy in patients with gastric DLBCL. METHODS: Univariate (P < 0.10) and multivariate (P < 0.05) analyses were used to identify factors associated with a CR to treatment. As a result, a system was developed to evaluate whether gastric DLBCL patients had a CR to chemotherapy. Evidence was found to support the model's ability to predict outcomes and demonstrate clinical value. RESULTS: We retrospectively analysed 108 people who had been diagnosed gastric DLBCL; 53 were in CR. Patients were divided at random into a 5:4 training/testing dataset split. ß2 microglobulin before and after chemotherapy and lesion length after chemotherapy were independent predictors of the CR of gastric DLBCL patients after chemotherapy. These factors were used in the predictive model construction. In the training dataset, the area under the curve (AUC) of the model was 0.929, the specificity was 0.806, and the sensitivity was 0.862. In the testing dataset, the model had an AUC of 0.957, specificity of 0.792, and sensitivity of 0.958. The AUC did not differ significantly between the training and testing dates (P > 0.05). CONCLUSION: A model constructed using imaging features combined with clinicopathological factors could effectively evaluate the CR to chemotherapy in gastric DLBCL patients. The predictive model can facilitate the monitoring of patients and be used to adjust individualised treatment plans.

Effects of magnetic resonance imaging (MRI)-detected extramural vascular invasion (mrEMVI) and tumor deposits (TDs) on distant metastasis and long-term survival after surgery for stage III rectal cancer: a retrospective study grouped based on the relationship between the bottom of the tumor and peritoneal reflection.

Background: To evaluate the effect of magnetic resonance imaging (MRI)-detected extramural vascular invasion (mrEMVI) and tumor deposits (TDs) on distant metastasis and long-term survival after surgery for stage III rectal cancer based on the relationship between the bottom of the tumor and peritoneal reflection. Methods: A retrospective study was performed on 694 patients who underwent radical resection for rectal cancer at the Harbin Medical University Tumor Hospital from October 2016 to October 2021. According to the surgical records, a new group was established based on the relationship between the lower end of the tumor and peritoneal reflection. On the peritoneal reflection group: the tumors are all located on the peritoneal reflection. Across the peritoneal reflection group: the tumors recurred across the peritoneal reflection. Under the peritoneal reflection group: the tumors are all located under the peritoneal reflection. We evaluated the effects of mrEMVI and TDs on postoperative distant metastasis and long-term survival of stage III rectal cancer by combining mrEMVI with TDs. Results: In the whole study population, neoadjuvant therapy (P=0.003) was negatively correlated with distant metastasis after rectal cancer surgery. Also, mesorectal fascia (MRF) (P=0.024), postoperative distant metastasis (P<0.001), and TDs (P<0.001) were independent risk factors for long-term survival after rectal cancer surgery. Lymph node metastasis (P<0.001) and neoadjuvant therapy (P=0.023) were independent risk factors for the presence or absence of TDs of rectal cancer. In the non-neoassisted subgroup, postoperative distant metastasis (P<0.001) was considered to be an independent risk factor for long-term survival after rectal cancer surgery. Conclusions: In the under the peritoneal reflection group, the combination of mrEMVI and TDs seems to play a certain guiding role in predicting distant metastasis and long-term survival after rectal cancer surgery.

A unique hyperdynamic dimer interface permits small molecule perturbation of the melanoma oncoprotein MITF for melanoma therapy.

Microphthalmia transcription factor (MITF) regulates melanocyte development and is the "lineage-specific survival" oncogene of melanoma. MITF is essential for melanoma initiation, progression, and relapse and has been considered an important therapeutic target; however, direct inhibition of MITF through small molecules is considered impossible, due to the absence of a ligand-binding pocket for drug design. Here, our structural analyses show that the structure of MITF is hyperdynamic because of its out-of-register leucine zipper with a 3-residue insertion. The dynamic MITF is highly vulnerable to dimer-disrupting mutations, as we observed that MITF loss-of-function mutations in human Waardenburg syndrome type 2 A are frequently located on the dimer interface and disrupt the dimer forming ability accordingly. These observations suggest a unique opportunity to inhibit MITF with small molecules capable of disrupting the MITF dimer. From a high throughput screening against 654,650 compounds, we discovered compound TT-012, which specifically binds to dynamic MITF and destroys the latter's dimer formation and DNA-binding ability. Using chromatin immunoprecipitation assay and RNA sequencing, we showed that TT-012 inhibits the transcriptional activity of MITF in B16F10 melanoma cells. In addition, TT-012 inhibits the growth of high-MITF melanoma cells, and inhibits the tumor growth and metastasis with tolerable toxicity to liver and immune cells in animal models. Together, this study demonstrates a unique hyperdynamic dimer interface in melanoma oncoprotein MITF, and reveals a novel approach to therapeutically suppress MITF activity.

Prediction scores of postoperative liver metastasis and long-term survival of pancreatic head cancer based on the distance between the mesenteric vessels and tumor, preoperative serum carbohydrate antigen 19-9 level, and lymph node metastasis rate.

BACKGROUND: The shortest distance between the superior mesenteric artery (SMA) or superior mesenteric vein (SMV) and the tumor margin was combined with preoperative serum carbohydrate antigen (CA) 19-9 and lymph node ratio (LNR) to evaluate joint effects on long-term survival and liver metastasis in patients with pancreatic head cancer after radical surgery. METHODS: This retrospective study included 149 patients who underwent pancreaticoduodenectomy for pancreatic head cancer at Harbin Medical University Tumor Hospital from May 2011 to March 2021. The preoperative serum CA 19-9 level and LNR were combined with the SMA or SMV distance. The joint association between long-term survival and postoperative liver metastasis was evaluated. RESULTS: Based on the receiver operating characteristic curve of postoperative liver metastasis or long-term survival, the optimal cut-off values of SMV distance were 3.1 and 0.7 mm, respectively, whereas the optimal cut-off value of SMA distance was 10.25 mm. The univariate model identified the liver metastasis score (p < 0.001) as a negative factor for postoperative liver metastasis of pancreatic head carcinoma. The SMV distance (p = 0.003), SMA distance (p < 0.001), LNR score (p < 0.001), and survival score (p < 0.001) were negatively correlated with long-term survival after pancreatic head cancer. The multivariate model highlighted SMA distance (p < 0.001), survival score (p = 0.001), and LNR score (p < 0.001) as independent risk factors for long-term survival in pancreatic head cancer. CONCLUSION: Liver metastasis score may be an independent predictor of postoperative liver metastasis in patients with pancreatic head cancer. Survival and LNR scores may be independent predictors of long-term postoperative survival in patients with pancreatic head cancer. However, the LNR score appears to improve long-term survival.

Clinical Application of Allograft Bone of Alveolar Cleft Repair.

OBJECTIVES: To investigate the osteogenic effect of allograft bone (BIO-GENE) and autologous iliac crest bone graft in the alveolar cleft repair. MATERIALS AND METHODS: A total of 131 patients with congenital unilateral alveolar cleft who consulted in our hospital from January 2016 to May 2021 were selected and divided into 3 groups according to the different bone restoration materials used. Group A totaling 43 cases was the autologous bone group; group B totaling 41 cases was the BIO-GENE group; and group C totaling 47 cases was the BMP-2+BIO-GENE group. The preoperative and postoperative cone beam CT data of the same patient were imported into MIMICS 21.0 in DICOM format. The preoperative cleft volume and newly formed bone volume were calculated by 3-dimensional reconstruction to measure their osteogenic rate. RESULTS: The differences in osteogenesis rates were not statistically significant in the group B compared with the group A, and in the group C compared with the group B ( P >0.05 for both). The differences in osteogenesis rates were statistically significant in the group C compared with the group A ( P =0.003). CONCLUSIONS: Comparative studies found the allograft bone with an ideal artificial material to repair alveolar clefts has become possible. Meanwhile, the addition of BMP-2 in the allograft bone significantly increased the osteogenic rate.

Fe-BPsalan Complex-Catalyzed Asymmetric [4 + 2] Cycloaddition of Cyclopentadiene with α,ß-Unsaturated Heterocycles.

An efficient iron-catalyzed asymmetric [4 + 2] cycloaddition of cyclopentadiene with α,ß-unsaturated acyl imidazoles or 2-cinnamoylisoindoline-1,3-dione derivatives was developed to afford the addition products in high yield and selectivity. Interestingly, the absolute structures of the addition products were controlled by the auxiliaries via different coordination modes with the same type of catalyst.

A Clinical Assessment of a Magnetic Resonance Computer-Aided Diagnosis System in the Detection of Pathological Complete Response After Neoadjuvant Chemotherapy in Breast Cancer.

Purpose: This study aimed to assess the diagnostic performance and the added value to radiologists of different levels of a computer-aided diagnosis (CAD) system for the detection of pathological complete response (pCR) after neoadjuvant chemotherapy (NAC) in patients with breast cancer. Besides, to investigate whether tumor molecular typing is associated with the efficiency of diagnosis of the CAD systems. Methods: 470 patients were identified with breast cancers who underwent NAC and post MR imaging between January 2016 and March 2019. The diagnostic performance of radiologists of different levels and the CAD system were compared. The added value of the CAD system was assessed and subgroup analyses were performed according to the tumor molecular typing. Results: Among 470 patients, 123 (26%) underwent pCR. The CAD system showed a comparable specificity as the senior radiologist (83.29% vs. 84.15%, p=0.488) and comparable area under the curve (AUC) (0.839 vs. 0.835, p =0.452). The performance of all radiologists significantly improved when aided by the CAD system (P<0.05), And there were no statistical differences in terms of sensitivity, specificity and accuracy between the two groups with CAD assistance(p>0.05).The AUC values for identifying pCR in TN patients were significant (0.883, 95%CI: 0.801-0.964, p < 0.001). Conclusion: The CAD system assessed in this study improves the performance of all radiologists, regardless of experience. The molecular typing of breast cancer is potential influencer of CAD diagnostic performance.

Biochemical characterization and mutational analysis of a novel flap endonuclease 1 from Thermococcus barophilus Ch5.

Flap endonuclease 1 (FEN1) plays important roles in DNA replication, repair and recombination. Herein, we report biochemical characteristics and catalytic mechanism of a novel FEN1 from the hyperthermophilic euryarchaeon Thermococcus barophilus Ch5 (Tb-FEN1). As expected, the recombinant Tb-FEN1 can cleave 5'-flap DNA. However, the enzyme has no activity on cleaving pseudo Y DNA, which sharply contrasts with other archaeal and eukaryotic FEN1 homologs. Tb-FEN1 retains 24% relative activity after heating at 100 °C for 20 min, demonstrating that it is the most thermostable among all reported FEN1 proteins. The enzyme displays maximal activity in a wide range of pH from 7.0 to 9.5. The Tb-FEN1 activity is dependent on a divalent metal ion, among which Mg2+ and Mn2+ are optimal. Enzyme activity is inhibited by NaCl. Kinetic analyzes estimated that an activation energy for removal of 5'-flap from DNA by Tb-FEN1 was 35.7 ± 4.3 kcal/mol, which is the first report on energy barrier for excising 5'-flap from DNA by a FEN1 enzyme. Mutational studies demonstrate that the K87A, R94A and E154A amino acid substitutions abolish cleavage activity and reduce 5'-flap DNA binding efficiencies, suggesting that residues K87, R94, and E154 in Tb-FEN1 are essential for catalysis and DNA binding as well. Overall, Tb-FEN1 is an extremely thermostable endonuclease with unusual features.

Computer-aided classification of MRI for pathological complete response to neoadjuvant chemotherapy in breast cancer.

Background: To determine suitable optimal classifiers and examine the general applicability of computer-aided classification to compare the differences between a computer-aided system and radiologists in predicting pathological complete response (pCR) from patients with breast cancer receiving neoadjuvant chemotherapy. Methods: We analyzed a total of 455 masses and used the U-Net network and ResNet to execute MRI segmentation and pCR classification. The diagnostic performance of radiologists, the computer-aided system and a combination of radiologists and computer-aided system were compared using receiver operating characteristic curve analysis. Results: The combination of radiologists and computer-aided system had the best performance for predicting pCR with an area under the curve (AUC) value of 0.899, significantly higher than that of radiologists alone (AUC: 0.700) and computer-aided system alone (AUC: 0.835). Conclusion: An automated classification system is feasible to predict the pCR to neoadjuvant chemotherapy in patients with breast cancer and can complement MRI.

Immunomodulating nano-adaptors potentiate antibody-based cancer immunotherapy.

Modulating effector immune cells via monoclonal antibodies (mAbs) and facilitating the co-engagement of T cells and tumor cells via chimeric antigen receptor- T cells or bispecific T cell-engaging antibodies are two typical cancer immunotherapy approaches. We speculated that immobilizing two types of mAbs against effector cells and tumor cells on a single nanoparticle could integrate the functions of these two approaches, as the engineered formulation (immunomodulating nano-adaptor, imNA) could potentially associate with both cells and bridge them together like an 'adaptor' while maintaining the immunomodulatory properties of the parental mAbs. However, existing mAbs-immobilization strategies mainly rely on a chemical reaction, a process that is rough and difficult to control. Here, we build up a versatile antibody immobilization platform by conjugating anti-IgG (Fc specific) antibody (αFc) onto the nanoparticle surface (αFc-NP), and confirm that αFc-NP could conveniently and efficiently immobilize two types of mAbs through Fc-specific noncovalent interactions to form imNAs. Finally, we validate the superiority of imNAs over the mixture of parental mAbs in T cell-, natural killer cell- and macrophage-mediated antitumor immune responses in multiple murine tumor models.

Sirtuin 3 is required for the protective effect of Resveratrol on Manganese-induced disruption of mitochondrial biogenesis in primary cultured neurons.

Chronic manganese (Mn) exposure can disturb mitochondrial homeostasis leading to mitochondrial dysfunction, which is involved in Mn-induced neurodegenerative diseases. Resveratrol (RSV), as a promoter of mitochondrial biogenesis, plays a significant role against mitochondrial dysfunction. However, whether RSV can relieve Mn-induced neuronal injury and mitochondrial dysfunction remains unknown. Sirtuin 3 (SIRT3), a main mitochondrial sirtuin, is an important regulator of mitochondria to maintain mitochondrial homeostasis. Therefore, this study investigated whether SIRT3 was required for RSV alleviating Mn-induced mitochondrial dysfunction in primary cultured neurons from C57BL/6 mice. Here, we showed that Mn (100 and 200 µM) exposure for 24 hr caused significant neuronal damage and mitochondrial dysfunction through increasing mitochondrial ROS, reducing mitochondrial membrane potential and adenosine triphosphate level, and leading to mitochondrial network fragmentation, which could be ameliorated by RSV pretreatment in primary cultured neurons. Additionally, our results also indicated that RSV could activate the SIRT1/PGC-1α signaling pathway and alleviate Mn-induced disruption of mitochondrial biogenesis by increasing SIRT1 expression and activity, enhancing deacetylation of PGC-1α. Furthermore, SIRT3 over-expression increased deacetylation of mitochondrial transcription factor A and mitochondrial DNA (mtDNA) copy number. Oppositely, silencing SIRT3 increased acetylation of mitochondrial transcription factor A and decreased mtDNA copy number. Our results showed SIRT3 was required for the protective effect of RSV in mitochondrial biogenesis. In conclusion, our findings demonstrated that RSV could ameliorate Mn-induced neuronal injury and mitochondrial dysfunction in primary cultured neurons through activating the SIRT1/ PGC-1α signaling pathway, and that SIRT3 is required for promoting mitochondrial biogenesis and attenuating Mn-induced mitochondrial dysfunction.

Resveratrol ameliorates disorders of mitochondrial biogenesis and mitophagy in rats continuously exposed to benzo(a)pyrene from embryonic development through adolescence.

Exposure to benzo(a)pyrene (BaP) is associated with poor neurodevelopment in children and memory impairment in adults. Previous research has demonstrated that mitochondrial damage plays an important role in BaP-induced neurotoxicity. Of interest, increasing evidence has suggested that resveratrol (RSV) can alleviate nerve cell damage, however the exact mechanisms of biological activity in mitochondria are not fully understood. In the current study, Wistar rats were exposed to BaP (1, 2, 4 mg/kg) and/or RSV (15, 30 mg/kg) during embryonic development and adolescence, and learning and memory ability, mitochondrial damage, and the expression of proteins associated with mitochondrial biogenesis and mitophagy were evaluated. These studies indicated that 2 and 4 mg/kg BaP could induce disorders of mitochondrial biogenesis and mitophagy, which leads to abnormal nerve cell development. However, pretreatment with 30 mg/kg RSV alleviated cell damage and the disorder of mitochondrial biogenesis by activating the AMPK/PGC-1α signaling pathway and promoting mitophagy. These findings suggested that RSV had utility in promoting mitochondrial homeostasis against BaP-induced nerve cell damage in the hippocampus of rats.

Resveratrol prevents benzo(a)pyrene-induced disruption of mitochondrial homeostasis via the AMPK signaling pathway in primary cultured neurons.

Exposure to benzo(a)pyrene (BaP) has been shown to cause mitochondrial dysfunction and injury to neural cells. Resveratrol (RSV) has been studied as an antioxidant, anti-inflammatory, anti-apoptotic, and anticancer agent and can modulate mitochondrial function in vitro and in vivo. However, the molecular mechanisms underlying RSV's protection against mitochondrial dysfunction have not been fully elucidated. To investigate whether RSV can effectively prevent BaP-induced mitochondrial dysfunction, we tested the effects of RSV in primary neuronal models. Our results confirmed that neurons exhibited mitochondrial dysfunction and apoptosis in the mitochondrial pathway after BaP-treatment, and that pretreatment with RSV could reduce that dysfunction. Further, our results indicated that RSV pretreatment enhanced mitochondrial biogenesis via the AMPK/PGC-1α pathway and activated mitophagy via the PINK1-Parkin and AMPK/ULK1 pathways, thereby coordinating mitochondrial homeostasis. We also found that RSV could alleviate mitochondrial network fragmentation caused by BaP. This work provided insights into the role of RSV in preventing BaP-induced primary neuronal apoptosis in the mitochondrial pathway, mainly via regulation of mitochondrial biogenesis and mitophagy through AMPK pathway, thus maintaining the integrity of the mitochondrial network.

Targeting of NLRP3 inflammasome with gene editing for the amelioration of inflammatory diseases.

The NLRP3 inflammasome is a well-studied target for the treatment of multiple inflammatory diseases, but how to promote the current therapeutics remains a large challenge. CRISPR/Cas9, as a gene editing tool, allows for direct ablation of NLRP3 at the genomic level. In this study, we screen an optimized cationic lipid-assisted nanoparticle (CLAN) to deliver Cas9 mRNA (mCas9) and guide RNA (gRNA) into macrophages. By using CLAN encapsulating mCas9 and gRNA-targeting NLRP3 (gNLRP3) (CLANmCas9/gNLRP3), we disrupt NLRP3 of macrophages, inhibiting the activation of the NLRP3 inflammasome in response to diverse stimuli. After intravenous injection, CLANmCas9/gNLRP3 mitigates acute inflammation of LPS-induced septic shock and monosodium urate crystal (MSU)-induced peritonitis. In addition, CLANmCas9/gNLRP3 treatment improves insulin sensitivity and reduces adipose inflammation of high-fat-diet (HFD)-induced type 2 diabetes (T2D). Thus, our study provides a promising strategy for treating NLRP3-dependent inflammatory diseases and provides a carrier for delivering CRISPR/Cas9 into macrophages.

Cationic Polymeric Nanoparticle Delivering CCR2 siRNA to Inflammatory Monocytes for Tumor Microenvironment Modification and Cancer Therapy.

Accumulating evidence has confirmed that malignant tumors have a complex microenvironment, which consists of a heterogeneous collection of tumor cells and other cell subsets (including the full gamut of immune cells). Tumor-associated macrophages (TAMs), derived from circulating Ly6Chi monocytes, constitute the most substantial fraction of tumor-infiltrating immune cells in nearly all cancer types and contribute to tumor progression, vascularization, metastasis, immunosuppression, and therapeutic resistance. Interrupting monocyte recruitment to tumor tissues by disturbing pivotal signaling pathways (such as CCL2-CCR2) is viewed as one of the most promising avenues for tumor microenvironment manipulation and cancer therapy. One critical issue for monocyte-based therapy is to deliver therapeutic agents into monocytes efficiently. In the present study, we systematically investigated the relationship between the surface potential and the biodistribution of polymeric nanoparticles in monocytes in vivo, aiming to screen and identify an appropriate delivery system for monocyte targeting, and we found that cationic nanoparticles have a higher propensity to accumulate in monocytes compared with their neutral counterparts. We further demonstrated that siCCR2-encapsulated cationic nanoparticle (CNP/siCCR2) could modify immunosuppressive tumor microenvironment more efficiently and exhibit superior antitumor effect in an orthotopic murine breast cancer model.