The Serine Protease Inhibitor Protease Nexin-1 Controls Mammary Cancer Metastasis through LRP-1–Mediated MMP-9 Expression

Macrophage polarization in the tumor microenvironment: Emerging roles and therapeutic potentials

The tumor microenvironment (TME) is a combination of tumor cells and indigenous host stroma, which consists of tumor-infiltrating immune cells, endothelial cells, fibroblasts, pericytes, and non-cellular elements. Tumor-associated macrophages (TAMs) represent the major tumor-infiltrating immune cell type and are generally polarized into two functionally contradictory subtypes, namely classical activated M1 macrophages and alternatively activated M2 macrophages. Macrophage polarization refers to how macrophages are activated at a given time and space. The interplay between the TME and macrophage polarization can influence tumor initiation and progression, making TAM a potential target for cancer therapy. Here, we review the latest investigations on factors orchestrating macrophage polarization in the TME, how macrophage polarization affects tumor progression, and the perspectives in modulating macrophage polarization for cancer immunotherapy.

Restoring BARX2 in OSCC reverses partial EMT and suppresses metastasis through miR-186-5p/miR-378a-3p-dependent SERPINE2 inhibition

Tumor cells undergoing partial epithelial-mesenchymal transition (pEMT) are pivotal in local invasion and lymphatic metastasis of oral squamous cell carcinoma (OSCC), yet the mechanisms behind pEMT reversal remain poorly understood. In this study, the loss of BARX2 expression was revealed during the process of oral epithelial carcinogenesis and identified to activate the pEMT program, facilitate metastasis, and be associated with poor prognosis. Restoring BARX2 expression in OSCC cell lines effectively reversed tumor pEMT, evident in E/N-Cadherin switching, reduced cell invasion, proliferation, and stemness, and inhibited murine lung metastasis. BARX2 re-expression negatively correlated with several pEMT markers, notably SERPINE2, which was enriched in the invasive OSCC front, enhancing stemness and promoting metastasis, particularly in cervical lymph nodes. Furthermore, rescuing SERPINE2 impaired the inhibitory effect of BARX2 on the pEMT programs and reconstructed ECM through re-expression of MMP1. Mechanistically, we identified that BARX2 inhibited SERPINE2 through activating miR-186-5p and miR-378a-3p. These miRNAs, upregulated by BARX2, post-transcriptionally degraded SERPINE2 mRNA via targeting specific sequences. Blocking miR-186-5p and miR-378a-3p effectively abolished the negative regulatory effect of BARX2 on SERPINE2. Overall, our findings highlight BARX2 as a partial EMT-reverser in OSCC, providing fresh therapeutic prospects for restoring BARX2 signaling to inhibit invasion and metastasis.

A new Neu-a syngeneic model of spontaneously metastatic HER2-positive breast cancer

Metastatic disease results from the dissemination of tumor cells beyond their organ of origin to grow in distant organs and is the primary cause of death in patients with advanced breast cancer. Preclinical murine models in which primary tumors spontaneously metastasize are valuable tools for studying metastatic progression and novel cancer treatment combinations. Here, we characterize a novel syngeneic murine breast tumor cell line that provides a model of spontaneously metastatic neu-expressing breast cancer with quicker onset of widespread metastases after orthotopic mammary implantation in immune-competent NeuN mice. The NT2.5-lung metastasis (-LM) cell line was derived from serial passaging of tumor cells that were macro-dissected from spontaneous lung metastases after orthotopic mammary implantation of parental NT2.5 cells. Within one week of NT2.5-LM implantation, metastases are observed in the lungs. Within four weeks, metastases are also observed in the bones, spleen, colon, and liver. We demonstrate that NT2.5-LM metastases are positive for NeuN-the murine equivalent of human epidermal growth factor 2 (HER2). We further demonstrate altered expression of markers of epithelial-to-mesenchymal transition (EMT), suggestive of their enhanced metastatic potential. Genomic analyses support these findings and reveal enrichment in EMT-regulating pathways. In addition, the metastases are rapidly growing, proliferative, and responsive to HER2-directed therapy. The new NT2.5-LM model provides certain advantages over the parental NT2/NT2.5 model, given its more rapid and spontaneous development of metastases. Besides investigating mechanisms of metastatic progression, this new model may be used for the rationalized development of novel therapeutic interventions and assessment of therapeutic responses.

Serpin peptidase inhibitor, clade E, member 2 in physiology and pathology: recent advancements

Serine protease inhibitors (serpins) are the most numerous and widespread multifunctional protease inhibitor superfamily and are expressed by all eukaryotes. Serpin E2 (serpin peptidase inhibitor, clade E, member 2), a member of the serine protease inhibitor superfamily is a potent endogenous thrombin inhibitor, mainly found in the extracellular matrix and platelets, and expressed in numerous organs and secreted by many cell types. The multiple functions of serpin E2 are mainly mediated through regulating urokinase-type plasminogen activator (uPA, also known as PLAU), tissue-type plasminogen activator (tPA, also known as PLAT), and matrix metalloproteinase activity, and include hemostasis, cell adhesion, and promotion of tumor metastasis. The importance serpin E2 is clear from its involvement in numerous physiological and pathological processes. In this review, we summarize the structural characteristics of the Serpin E2 gene and protein, as well as its roles physiology and disease.

Mimicking the breast metastatic microenvironment: characterization of a novel syngeneic model of HER2+ breast cancer

Preclinical murine models in which primary tumors spontaneously metastasize to distant organs are valuable tools to study metastatic progression and novel cancer treatment combinations. Here, we characterize a novel syngeneic murine breast tumor cell line, NT2.5-lung metastasis (-LM), that provides a model of spontaneously metastatic neu-expressing breast cancer with quicker onset of widespread metastases after orthotopic mammary implantation in immune-competent NeuN mice. Within one week of orthotopic implantation of NT2.5-LM in NeuN mice, distant metastases can be observed in the lungs. Within four weeks, metastases are also observed in the bones, spleen, colon, and liver. Metastases are rapidly growing, proliferative, and responsive to HER2-directed therapy. We demonstrate altered expression of markers of epithelial-to-mesenchymal transition (EMT) and enrichment in EMT-regulating pathways, suggestive of their enhanced metastatic potential. The new NT2.5-LM model provides more rapid and spontaneous development of widespread metastases. Besides investigating mechanisms of metastatic progression, this new model may be used for the rationalized development of novel therapeutic interventions and assessment of therapeutic responses targeting distant visceral metastases.

Serpin peptidase inhibitor, clade E, member 2 is associated with malignant progression and clinical prognosis in oral squamous cell carcinoma

Background/purpose

The serpin peptidase inhibitor, clade E, member 2 (SERPINE2), is upregulated in breast cancer, prostate cancer, and urothelial carcinoma; however, limited information exists regarding its expression in oral cancer. Therefore, this study aimed to analyze the association between SERPINE2 expression and oral squamous cell carcinoma (OSCC) outcomes.

Materials and methods

SERPINE2 mRNA and protein expression in patients with head and neck squamous cell carcinoma and OSCC were investigated using online databases and tissue-array analysis. Its relationship with clinicopathological characteristics, OSCC prognosis and its biological function in OSCC cells were explored.

Results

Analysis using online databases revealed higher SERPINE2 expression in tumor tissues and its role as a prognostic factor. High SERPINE2 protein levels were significantly correlated with adverse pathological parameters, including advanced clinical stage and tumor status (P < 0.001), lymph nodes (P = 0.014), and distant metastases (P = 0.013). High SERPINE2 expression was associated with worse overall survival (P < 0.001) and was identified as an independent prognostic factor for OSCC. In vitro studies revealed that SERPINE2 knockdown significantly reduced cell proliferation, migration, and invasion in OSCC cell lines.

Conclusion

This study suggests that SERPINE2 may serve as a prognostic biomarker and potential therapeutic target for oral cancer.

Microdissection of cancer-associated fibroblast infiltration subtypes unveils the secreted SERPINE2 contributing to immunosuppressive microenvironment and immuotherapeutic resistance in gastric cancer: A large-scale study integrating bulk and single-cell transcriptome profiling

In the era of immunotherapy, the suboptimal response rate and the development of acquired resistance among the initial beneficiaries continue to present significant challenges across multiple malignancies, including gastric cancer (GC). Considering that the interactions of tumor stroma, especially the cancer-associated fibroblasts (CAFs), with immune and tumor cells, play indispensable roles in tumor progression, tumor microenvironment remodeling and therapeutic responsiveness, in-depth exploration on the roles of CAFs and pivotal mediators of their functions may provide novel clues to increase the effectiveness of current immunotherapeutic drugs and further achieve synergistic antitumor response. Herein, through the consensus clustering of canonical biomarkers, three GC subclasses with different abundance of CAFs were virtually microdissected in four integrated bulk cohorts encompassing 2148 GC patients from 11 independent datasets. An extensive immunogenomic analysis revealed that tumors with high CAFs infiltration were characterized with unfavorable outcomes, aggressive phenotypes, decreased tumor immunogenicity, high risk of immune evasion and thus immunotherapeutic resistance. By leveraging large-scale single-cell transcriptomic profiling, a series of CAF-secreted proteins were identified, among which the SERPINE2 was confirmed to be restrictively enriched in stromal fibroblasts of GC tissues and contribute to promoting a protumor milieu and fostering an immunosuppressive microenvironment via bioinformatics computations and tissue microarray analysis. Moreover, pan-cancer investigations generalized the immunological roles of SERPINE2, especially in pan-gastrointestinal malignancies, with multiple real-world immunotherapy cohorts further confirming its implications on predicting immunotherapeutic efficacy. In conclusion, these findings suggest that the CAF-derived SERPINE2 is a promising immune-oncology target with therapeutic implications to further synergize the immunotherapeutic combinations.

Growth differentiation factor myostatin regulates epithelial-mesenchymal transition genes and enhances invasion by increasing serine protease inhibitors E1 and E2 in human trophoblast cells

Placental insufficiency disorders, including preeclampsia and intrauterine growth restriction, are major obstetric complications that can have devastating effects on both the mother and the fetus. These syndromes have underlying poor placental trophoblast cell invasion into uterine tissues. Placental invasion is controlled by many hormones and growth factors. Myostatin (MSTN) is a transforming growth factor-β superfamily member recognized for its important role in muscle growth control. MSTN has also been shown to be secreted and functioning in the placenta, and its serum and/or placental levels were found to be upregulated in preeclampsia and intrauterine growth restriction. Considering that the mechanistic role of MSTN in placentation remains poorly understood, we hypothesized that MSTN uses ALK4/5-SMAD2/3/4 signaling to increase human trophoblast invasion through a group of epithelial-mesenchymal transition genes including SERPINE2, PAI-1, and SOX4. mRNA sequencing of control and MSTN-treated primary human trophoblast cells (n = 5) yielded a total of 610 differentially expressed genes (false discovery rate <0.05) of which 380 genes were upregulated and 230 were downregulated. These differentially expressed genes were highly enriched in epithelial-mesenchymal transition genes, and a subset including SERPINE2, PAI-1, and SOX4 was investigated for its role in MSTN-induced trophoblast cell invasion. We found that MSTN induced upregulation of SERPINE2 via ALK4/5-SMAD2/3/4 signaling; however, SMAD2 was not involved in MSTN-induced PAI-1 upregulation. SOX4 was involved in MSTN-induced upregulation of SERPINE2, but not PAI-1. Collectively, this study discovers novel molecular mechanisms of MSTN-induced human trophoblast cell invasion and provides insight into the functional consequences of its dysregulation in placental insufficiency disorders.

The endocytic receptor protein LRP-1 modulate P-glycoprotein mediated drug resistance in MCF-7 cells

Multidrug resistance (MDR) is a major obstacle to successful cancer chemotherapy. A typical form of MDR is due to the overexpression of membrane transport proteins., such as Glycoprotein-P (P-gp), resulting in an increased drug efflux preventing drug cytotoxicity. P-gp is mainly localized on the plasma membrane; however, it can also be endocytosed resulting in the trafficking of P-gp in endoplasmic reticulum, Golgi, endosomes, and lysosomes. The lysosomal P-gp has been found to be capable of transporting and sequestering P-gp substrates (e.g., Doxorubicin (Dox)) into lysosomes to protect cells against cytotoxic drugs. Many translational studies have shown that low-density lipoprotein receptor-related protein-1 (LRP-1) is involved in endocytosis and regulation of signalling pathways. LRP-1 mediates the endocytosis of a diverse set of extracellular ligands that play important roles in tumor progression. Here, we investigated the involvement of LRP-1 in P-gp expression and subcellular redistribution from the cell surface to the lysosomal membrane by endocytosis and its potential implication in P-gp-mediated multidrug resistance in MCF-7 cells. Our results showed that MCF-7 resistant cells (MCF-7R) overexpressed the P-gp, LRP-1 and LAMP-1 and were 11.66-fold resistant to Dox. Our study also revealed that in MCF-7R cells, lysosomes were predominantly high density compared to sensitized cells and P-gp was localized in the plasma membrane and lysosomes. LRP-1 blockade reduced lysosomes density and level of LAMP-1 and P-gp. It also affected the subcellular distribution of P-gp. Under these conditions, we restored Dox nuclear uptake and ERK 1/2 activation thus leading to MCF-7R cell sensitization to Dox. Our data suggest that LRP-1 is able to modulate the P-gp expression and subcellular redistribution by endocytosis and to potentiate the P-gp-acquired Dox resistance.

Loss of Serpin E2 alters antimicrobial gene expression by microglia but not astrocytes

Microglia are the brain-resident immune cells responsible for surveilling and protecting the central nervous system. These cells can express a wide array of immune genes, and that expression can become highly dynamic in response to changes in the environment, such as traumatic injury or neurological disease. Though microglial immune responses are well studied, we still do not know many mechanisms and regulators underlying all the varied microglial responses. Serpin E2 is a serine protease inhibitor that acts on a wide variety of serine proteases, with particularly potent affinity for the blood clotting enzyme thrombin. In the brain, Serpin E2 is highly expressed by many cell types, especially glia, and loss of Serpin E2 leads to behavioral changes as well as deficits in synaptic plasticity. To determine whether Serpin E2 is important for maintaining homeostasis in glia, we performed RNA sequencing of microglia and astrocytes from Serpin E2-deficient mice in a healthy state or under immune activation due to lipopolysaccharide (LPS) injection. We found that microglia in Serpin E2-deficient mice had higher expression of antimicrobial genes, while astrocytes did not display any robust changes in transcription. Furthermore, the lack of Serpin E2 did not affect transcriptional responses to LPS in either microglia or astrocytes. Overall, we find that Serpin E2 is a regulator of antimicrobial genes in microglia.

CRISPR-Cas-amplified urinary biomarkers for multiplexed and portable cancer diagnostics

Synthetic biomarkers, bioengineered sensors that generate molecular reporters in diseased microenvironments, represent an emerging paradigm in precision diagnostics. Despite the utility of DNA barcodes as a multiplexing tool, their susceptibility to nucleases in vivo has limited their utility. Here we exploit chemically stabilized nucleic acids to multiplex synthetic biomarkers and produce diagnostic signals in biofluids that can be 'read out' via CRISPR nucleases. The strategy relies on microenvironmental endopeptidase to trigger the release of nucleic acid barcodes and polymerase-amplification-free, CRISPR-Cas-mediated barcode detection in unprocessed urine. Our data suggest that DNA-encoded nanosensors can non-invasively detect and differentiate disease states in transplanted and autochthonous murine cancer models. We also demonstrate that CRISPR-Cas amplification can be harnessed to convert the readout to a point-of-care paper diagnostic tool. Finally, we employ a microfluidic platform for densely multiplexed, CRISPR-mediated DNA barcode readout that can potentially evaluate complex human diseases rapidly and guide therapeutic decisions.

SerpinB3 Upregulates Low-Density Lipoprotein Receptor-Related Protein (LRP) Family Members, Leading to Wnt Signaling Activation and Increased Cell Survival and Invasiveness

Abnormal activation of the Wnt-β-catenin signaling cascade is involved in tumor growth and dissemination. SerpinB3 has been shown to induce β-catenin, and both molecules are overexpressed in tumors, particularly in those with poor prognoses. The aim of this study was to evaluate the ability of SerpinB3 to modulate the Wnt pathway in liver cancer and in monocytic cells, the main type of inflammatory cells in the tumor microenvironment. The Wnt cascade, Wnt co-receptors, and low-density lipoprotein receptor-related protein (LRP) members were analyzed in different cell lines and human monocytes in the presence or absence of SerpinB3. The Wnt-β-catenin axis was also evaluated in liver tumors induced in mice with different extents of SeprinB3 expression. In monocytic cells, SerpinB3 induced a significant upregulation of Wnt-1/7, nuclear β-catenin, and c-Myc, which are associated with increased cell lifespan and proliferation. In liver tumors in mice, the expression of β-catenin was significantly correlated with the presence of SerpinB3. In hepatoma cells, Wnt co-receptors LRP-5/6 and LRP-1, implicated in cell survival and invasiveness, were upregulated by SerpinB3. The LRP pan-inhibitor RAP not only induced a decrease in LRP expression, but also a dose-dependent reduction in SerpinB3-induced invasiveness. In conclusion, SerpinB3 determines the activation of the Wnt canonical pathway and cell invasiveness through the upregulation of LRP family members.

Targeting tumor exosomal circular RNA cSERPINE2 suppresses breast cancer progression by modulating MALT1-NF-𝜅B-IL-6 axis of tumor-associated macrophages

BACKGROUND

Circular RNAs (circRNAs) have important regulatory functions in cancer, but the role of circRNAs in the tumor microenvironment (TME) remains unclear. Moreover, we also explore the effects of si-circRNAs loaded in nanoparticles as therapeutic agent for anti-tumor in vivo.

METHODS

We conducted bioinformatics analysis, qRT-PCR, EdU assays, Transwell assays, co-culture system and multiple orthotopic xenograft models to investigate the expression and function of circRNAs. Additionally, PLGA-based nanoparticles loaded with si-circRNAs were used to evaluate the potential of nanotherapeutic strategy in anti-tumor response.

RESULTS

We identified oncogene SERPINE2 derived circRNA, named as cSERPINE2, which was notably elevated in breast cancer and was closely related to poor clinical outcome. Functionally, tumor exosomal cSERPINE2 was shuttled to tumor associated macrophages (TAMs) and enhanced the secretion of Interleukin-6 (IL-6), leading to increased proliferation and invasion of breast cancer cells. Furthermore, IL-6 in turn increased the EIF4A3 and CCL2 levels within tumor cells in a positive feedback mechanism, further enhancing tumor cSERPINE2 biogenesis and promoting the recruitment of TAMs. More importantly, we developed a PLGA-based nanoparticle loaded with si-cSERPINE2, which effectively attenuated breast cancer progression in vivo.

CONCLUSIONS

Our study illustrates a novel mechanism that tumor exosomal cSERPINE2 mediates a positive feedback loop between tumor cells and TAMs to promote cancer progression, which may serve as a promising nanotherapeutic strategy for the treatment of breast cancer.

Molecular Mechanisms of Inhibitory Effects of Bovine Lactoferrin on Invasion of Oral Squamous Cell Carcinoma

Lactoferrin (LF), an iron-binding glycoprotein, has been reported to have anticancer properties. However, the molecular mechanisms behind its anticancer effects on oral squamous cell carcinoma (OSCC) have not yet been elucidated. Therefore, we aimed to clarify the effects of LF on invasion of OSCC, and its underlying molecular mechanism. OSCC cell lines, HSC2 and HOC313, were treated with bovine LF (bLF). The effects of bLF on cell invasion were examined by a chamber migration assay, wound healing assay, and Boyden chamber method with a basement-membrane-analogue. Expression levels of MMP-1, MMP-3, and AP-1 were examined using RT-PCR, qRT-PCR, and western blotting. Roles of LRP1, a receptor of bLF, on cell invasion were analyzed using siLRP1 knockdown cells. Furthermore, to clarify the importance of LRP1 in invasion, the effects of bLF on tPA-induced invasion of OSCC cells were examined. The invasion assays showed that bLF suppressed invasion of the OSCC cells. Moreover, bLF down-regulated AP-1, and resulted in reductions of MMP-1 and MMP-3. With SiLRP1 knockdown, OSCC cells failed to induce their invasion, and bLF was not able to exert its effects on invasion. Furthermore, bLF remarkably inhibited tPA-induced cell invasion. These findings suggest the importance of LRP1 in bLF-suppressed invasion of OSCC cells via the reduction of AP-1 and MMP production.

Single-cell RNA-seq integrated with multi-omics reveals SERPINE2 as a target for metastasis in advanced renal cell carcinoma

Tumor growth, metastasis and therapeutic response are believed to be regulated by the tumor and its microenvironment (TME) in advanced renal cell carcinoma (RCC). However, the mechanisms underlying genomic, transcriptomic and epigenetic alternations in RCC progression have not been completely defined. In this study, single-cell RNA-sequencing (scRNA-seq) data were obtained from eight tissue samples of RCC patients, including two matched pairs of primary and metastatic sites (lymph nodes), along with Hi-C, transposable accessible chromatin by high-throughput (ATAC-seq) and RNA-sequencing (RNA-seq) between RCC (Caki-1) and human renal tubular epithelial cell line (HK-2). The identified target was verified in clinical tissue samples (microarray of 407 RCC patients, TMA-30 and TMA-2020), whose function was further validated by in vitro and in vivo experiments through knockdown or overexpression. We profiled transcriptomes of 30514 malignant cells, and 14762 non-malignant cells. Comprehensive multi-omics analysis revealed that malignant cells and TME played a key role in RCC. The expression programs of stromal cells and immune cells were consistent among the samples, whereas malignant cells expressed distinct programs associated with hypoxia, cell cycle, epithelial differentiation, and two different metastasis patterns. Comparison of the hierarchical structure showed that SERPINE2 was related to these NNMF expression programs, and at the same time targeted the switched compartment. SERPINE2 was highly expressed in RCC tissues and lowly expressed in para-tumor tissues or HK-2 cell line. SERPINE2 knockdown markedly suppressed RCC cell growth and invasion, while SERPINE2 overexpression dramatically promoted RCC cell metastasis both in vitro and in vivo. In addition, SERPINE2 could activate the epithelial-mesenchymal transition pathway. The above findings demonstrated that the role of distinct expression patterns of malignant cells and TME played a distinct role in RCC progression. SERPINE2 was identified as a potential therapeutic target for inhibiting metastasis in advanced RCC.

Upregulation of SERPINE2 Results in Poor Prognosis of Hepatoblastoma via Promoting Invasion Abilities

Background

Hepatoblastoma (HB) is the most common malignant liver tumor in children. High-risk patients, especially those with tumor metastasis, have poor prognosis. Serpin family E member 2 (SERPINE2) is overexpressed in a variety of tumors, especially adenocarcinoma, and promotes tumor invasion and metastasis. The function and mechanism of SERPINE2 in HB are still unclear. The purpose of this study was to investigate the potential clinical prognostic value and molecular mechanism of SERPINE2 in HB.

Methods

We performed bioinformatics analyses on HB microarray data GSE131329 to study the role of SERPINE2. The expression level of SERPINE2 in HB and its clinical significance were further analyzed by quantitative real-time polymerase chain reaction (qRT-PCR), Western blot, and immunohistochemistry. After constructing the SERPINE2 overexpression and knockdown in HepG2 and HUH6 cells, the 5-ethynyl-29-deoxyuridine (EdU) assay, wound healing assay, Transwell experiment, and apoptosis assay were performed to explore the role of SERPINE2 in HB progress.

Results

Upregulation of SERPINE2 was found in HB tissues and was associated with a poor prognosis. Moreover, the SERPINE2 expression was related to tumor size, vascular invasion, and tumor metastasis. The Cox regressions show that high SERPINE2 expression is an independent risk factor for HB. SERPINE2 overexpression remarkably enhanced HB cell migration and invasion and suppressed apoptosis, while knockdown of SERPINE2 exerted the opposite effect. In addition, SERPINE2 facilitated the epithelial to mesenchymal transformation (EMT) phenotype of HB cells in vitro.

Conclusion

Our findings indicated that SERPINE2 accelerates HB progression, suggesting that SERPINE2 may be a potential prognostic biomarker and an underlying therapeutic target for HB.

Metformin and histone deacetylase inhibitor based anti-inflammatory nanoplatform for epithelial-mesenchymal transition suppression and metastatic tumor treatment

Epithelial-mesenchymal transition (EMT), a differentiation process with aberrant changes of tumor cells, is identified as an initial and vital procedure for metastatic processes. Inflammation is a significant inducer of EMT and provides an indispensable target for blocking EMT, however, an anti-inflammatory therapeutic with highlighted safety and efficacy is deficient. Metformin is a promising anti-inflammatory agent with low side effects, but tumor monotherapy with an anti-inflammation drug could generate therapy resistance, cell adaptation or even promote tumor development. Combination therapies with various anti-inflammatory mechanisms can be favorable options improving therapeutic effects of metformin, here we develop a tumor targeting hybrid micelle based on metformin and a histone deacetylase inhibitor propofol-docosahexaenoic acid for efficient therapeutic efficacies of anti-inflammatory drugs. Triptolide is further encapsulated in hybrid micelles for orthotopic tumor therapies. The final multifunctional nanoplatforms (HAOPTs) with hyaluronic acid (HA) modification can target tumor efficiently, inhibit tumor cell EMT processes, repress metastasis establishment and suppress metastatic tumor development in a synergistic manner. Collectively, the results afford proof of concept that the tumor targeting anti-inflammatory nanoplatform can provide a potent, safe and clinical translational approach for EMT inhibition and metastatic tumor therapy.

A Kunitz-type inhibitor from tick salivary glands: A promising novel antitumor drug candidate

Salivary glands are vital structures responsible for successful tick feeding. The saliva of ticks contains numerous active molecules that participate in several physiological processes. A Kunitz-type factor Xa (FXa) inhibitor, similar to the tissue factor pathway inhibitor (TFPI) precursor, was identified in the salivary gland transcriptome of Amblyomma sculptum ticks. The recombinant mature form of this Kunitz-type inhibitor, named Amblyomin-X, displayed anticoagulant, antiangiogenic, and antitumor properties. Amblyomin-X is a protein that inhibits FXa in the blood coagulation cascade and acts via non-hemostatic mechanisms, such as proteasome inhibition. Amblyomin-X selectively induces apoptosis in cancer cells and promotes tumor regression through these mechanisms. Notably, the cytotoxicity of Amblyomin-X seems to be restricted to tumor cells and does not affect non-tumorigenic cells, tissues, and organs, making this recombinant protein an attractive molecule for anticancer therapy. The cytotoxic activity of Amblyomin-X on tumor cells has led to vast exploration into this protein. Here, we summarize the function, action mechanisms, structural features, pharmacokinetics, and biodistribution of this tick Kunitz-type inhibitor recombinant protein as a promising novel antitumor drug candidate.

LRP-1-dependent control of calpain expression and activity: A new mechanism regulating thyroid carcinoma cell adhesion

The low-density lipoprotein receptor-related protein 1 (LRP1) is a multifunctional endocytic receptor mediating the clearance of various molecules from the extracellular matrix. LRP1 also regulates cell surface expression of matrix receptors by modulating both extracellular and intracellular signals, though current knowledge of the underlying mechanisms remains partial in the frame of cancer cells interaction with matricellular substrates. In this study we identified that LRP1 downregulates calpain activity and calpain 2 transcriptional expression in an invasive thyroid carcinoma cell model. LRP1-dependent alleviation of calpain activity limits cell-matrix attachment strength and contributes to FTC133 cells invasive abilities in a modified Boyden chamber assays. In addition, using enzymatic assays and co-immunoprecipitation experiments, we demonstrated that LRP1 exerts post-translational inhibition of calpain activity through PKA-dependent phosphorylation of calpain-2. This LRP-1 dual mode of control of calpain activity fine-tunes carcinoma cell spreading. We showed that LRP1-mediated calpain inhibition participates in talin-positive focal adhesions dissolution and limits β1-integrin expression at carcinoma cell surface. In conclusion, we identified an additional and innovative intracellular mechanism which demonstrates LRP-1 pro-motile action in thyroid cancer cells. LRP-1 ability to specifically control calpain-2 expression and activity highlights a novel facet of its de-adhesion receptor status.

Low-Density Lipoprotein Receptor-Related Protein 8 at the Crossroad between Cancer and Neurodegeneration

The low-density-lipoprotein receptors represent a family of pleiotropic cell surface receptors involved in lipid homeostasis, cell migration, proliferation and differentiation. The family shares common structural features but also has significant differences mainly due to tissue-specific interactors and to peculiar proteolytic processing. Among the receptors in the family, recent studies place low-density lipoprotein receptor-related protein 8 (LRP8) at the center of both neurodegenerative and cancer-related pathways. From one side, its overexpression has been highlighted in many types of cancer including breast, gastric, prostate, lung and melanoma; from the other side, LRP8 has a potential role in neurodegeneration as apolipoprotein E (ApoE) and reelin receptor, which are, respectively, the major risk factor for developing Alzheimer’s disease (AD) and the main driver of neuronal migration, and as a γ-secretase substrate, the main enzyme responsible for amyloid formation in AD. The present review analyzes the contributions of LDL receptors, specifically of LRP8, in both cancer and neurodegeneration, pointing out that depending on various interactions and peculiar processing, the receptor can contribute to both proliferative and neurodegenerative processes.

Ginsenoside Rh4 Suppresses Metastasis of Esophageal Cancer and Expression of c-Myc via Targeting the Wnt/β-Catenin Signaling Pathway

The metastasis of esophageal squamous cell carcinoma (ESCC) is a leading cause of death worldwide, however, it has a poor prognosis. Ginsenoside Rh4 is a rare saponin that has been shown to have potential antitumor effectiveness in ESCC. However, the utility of Rh4 in ESCC metastasis and its undiscovered mode of action has not yet been explored. In this study, we found that Rh4 could inhibit ESCC metastasis by regulating the Wnt/β-catenin signaling pathway and the level of c-Myc, which is an important transcription factor in cancer. In in vitro experiments, Rh4 could inhibit the migration and invasion of ESCC cells without affecting cell viability. In in vivo experiments, Rh4 restrained ESCC metastasis to the lymph nodes and lungs via the suppression of epithelial-mesenchymal transition (EMT). The Wnt agonist HLY78 promoted EMT and migration of ESCC cells, whereas treatment of Rh4 can attenuate the promotion effect of HLY78. The siRNA knocking out c-Myc can also significantly reduce the expression of EMT-related marker proteins. This study illustrates a new concept for further research on the mechanism of Rh4 in ESCC.

Fluoroquinolones Suppress TGF-β and PMA-Induced MMP-9 Production in Cancer Cells: Implications in Repurposing Quinolone Antibiotics for Cancer Treatment

BACKGROUND

Fluoroquinolones (FQs) are potent antimicrobials with multiple effects on host cells and tissues. Although FQs can attenuate cancer invasion and metastasis, the underlying molecular mechanisms remain unclear. Matrix metalloproteinase-9 (MMP-9) has functional roles in tumor angiogenesis, invasion, and metastasis, and is associated with cancer progression and poor prognosis, suggesting that inhibitors of MMP-9 activity and transcription are prime candidates for cancer therapy. Despite numerous preclinical data supporting the use of MMP-9 inhibitors as anticancer drugs, the few available examples are not therapeutically useful due to low specificity and off-target effects. We examined the effects of FQs on MMP-9 production in cancer cells following transforming growth factor beta (TGF-β) and phorbol 12-myristate 13-acetate (PMA) stimulation.

EXPERIMENTAL APPROACHES

Using confluent cultures of HepG2 and A549 cells, the effects of FQs (ciprofloxacin, levofloxacin, clinafloxacin, gatifloxacin, and enrofloxacin) on TGF-β and PMA-induced MMP-9 mRNA expression and production were studied in RNA extracts and culture supernatants, respectively. FQs specifically abrogated TGF-β and PMA-induced MMP-9 levels and activity in a concentration and time-dependent manner, without affecting other MMPs or proteins involved in epithelial-mesenchymal transition. Additionally, FQs inhibited TGF-β and PMA-induced cell migration via p38 and cyclic AMP signaling pathways.

CONCLUSIONS AND IMPLICATIONS

Overall, we demonstrated that FQs inhibit cancer cell migration and invasion by downregulating MMP-9 expression and revealed the cellular mechanisms underlying their potential value in cancer treatment.

CSF1R Inhibition Combined with GM-CSF Reprograms Macrophages and Disrupts Protumoral Interplays with AML Cells

Relapse is a major issue in acute myeloid leukemia (AML) and while the contribution of gene mutations in developing drug resistance is well established, little is known on the role of macrophages (MΦs) in an AML cell microenvironment. We examined whether myeloblasts could educate MΦs to adopt a protumoral orientation supporting myeloblast survival and resistance to therapy. Flow cytometry analyses demonstrated that M2-like CD163⁺ MΦs are abundantly present, at diagnosis, in the bone marrow of AML patients. We showed that myeloblasts, or their conditioned medium, polarize monocytes to M2-like CD163⁺ MΦs, induce the secretion of many protumoral factors, and promote myeloblast survival and proliferation as long as close intercellular contacts are maintained. Importantly, pharmacologic inhibition of the CSF1 receptor (CSF1R), in the presence of GM-CSF, reprogrammed MΦ polarization to an M1-like orientation, induced the secretion of soluble factors with antitumoral activities, reduced protumoral agonists, and promoted the apoptosis of myeloblasts interacting with MΦs. Furthermore, myeloblasts, which became resistant to venetoclax or midostaurin during their interplay with protumoral CD163⁺ MΦs, regained sensitivity to these targeted therapies following CSF1R inhibition in the presence of GM-CSF. These data reveal a crucial role of CD163⁺ MΦ interactions with myeloblasts that promote myeloblast survival and identify CSF1R inhibition as a novel target for AML therapy.

SERPINE2 Overexpression Is Associated with Poor Prognosis of Urothelial Carcinoma

Recent studies have reported that SERPINE2 contributes to the development of various cancers. However, its association with urothelial carcinoma (UC) remains unclear. In this study, data on urinary bladder UC (UBUC) cases from The Cancer Genome Atlas (TCGA) database were used to investigate the prognostic value of SERPINE2 mRNA expression. Then, SERPINE2 expression was analyzed with tissue microarrays constructed from 117 upper tract UC (UTUC) and 84 UBUC tissue specimens using immunohistochemical staining. Results were compared to clinicopathologic data by multivariate analysis. In the TCGA database, high SERPINE2 mRNA expression indicated a poor prognosis in patients with UBUC. Furthermore, Mann-Whitney U test showed that high SERPINE2 immunoexpression was significantly associated with adverse pathologic parameters including invasion, high grade, coexistence of UC in situ, and advanced pT stage (all p < 0.05, except for a marginal association with high-grade UBUC, p = 0.066). Kaplan-Meier analysis revealed that high SERPINE2 expression was associated with worse overall survival (OS; UTUC, p = 0.003; UBUC, p = 0.014) and disease-free survival (UTUC, p = 0.031; UBUC, p = 0.033). Moreover, multivariate analysis identified high SERPINE2 expression as an independent prognostic factor for OS (UTUC, p = 0.002; UBUC, p = 0.024). Taken together, our findings demonstrated that increased SERPINE2 expression is associated with adverse pathologic features and may serve as a prognostic biomarker for UC.

Synthesis and Characterization of Salinomycin-Loaded High-Density Lipoprotein and Its Effects on Cervical Cancer Cells and Cervical Cancer Stem Cells

Background

Cervical cancer stem cells (CCSCs), a small part of tumor population, are one of the important reasons for metastasis and recurrence of cervical cancer. Targeting CCSCs may be an effective way to eliminate tumors. Salinomycin (Sal) has been proved to be an effective anticancer drug in many studies, especially for cancer stem cells (CSCs). However, the cytotoxicity of salinomycin limits its further research as an anticancer drug. High-density lipoprotein (HDL) nanoparticles are an excellent drug carrier, which can reduce the toxicity of Sal, have a certain targeting effect and improve the clinical benefit of Sal.

Methods

Salinomycin-loaded high-density lipoprotein (S-HDL) was synthesized and characterized by various analytical techniques. CD44^highCD24^low CCSCs were isolated from HeLa cells by magnetic separation. The uptake of HDL nanoparticles was observed by laser confocal microscopy, and the effect of S-HDL on the proliferation of CCCs and CCSCs was detected by cell viability analysis. Genome-wide analysis was used to analyze the effects of S-HDL on the biological processes of CCCs and then cell apoptosis, cell cycle and cell migration were selected for verification.

Results

S-HDL had a particle size of 38.98 ± 1.78 nm and an encapsulation efficiency of 50.73 ± 4.29%. Cell uptake analysis showed that HDL nanoparticles could enhance the drug uptake of CCCs and CCSCs and may target CCCs and CCSCs. In cell viability analysis, CCCs and CCSCs showed high sensitivity to S-HDL. S-HDL can more efficiently prevent CCSCs from developing tumorspheres than Sal in tumorsphere formation study. S-HDL had stronger ability to induce cell cycle arrest, promote cell apoptosis and inhibit cell migration compared with free Sal, which was consistent with the results of Genome Wide analysis.

Conclusion

S-HDL can effectively target and eliminate CCCs and CCSCs, which is a potential drug for the treatment of cervical cancer.

SERPINE2 is an oral cancer-promoting factor that induces angiogenesis and lymphangiogenesis

BACKGROUND

LEM domain containing 1 (LEMD1) is a novel factor involved in the development of oral squamous cell carcinoma (OSCC). We previously performed a microarray analysis and found that serpin peptidase inhibitor, clade E, member 2 (SERPINE2) is an LEMD1-related signal. SERPINE2 is an extracellular serine proteinase inhibitor with secretory capacity. Although SERPINE2 displays tumor-promoting properties in many cancers, some reports indicate that SRPINE2 also has a tumor-suppressing function. Therefore, there are many unclear points about its role in cancer. In this study, we investigated SERPINE2 expression in OSCC.

METHODS

The gene expression and secretion levels of SERPINE2 were examined in 42 frozen specimens of OSCC, and SERPINE2 immunostaining was investigated in 167 cases of OSCC. Furthermore, the effect of SERPINE2 on angiogenesis and lymphangiogenesis was analyzed using OSCC cells and endothelial cells.

RESULTS

In the frozen specimens, the gene expression (P < 0.0001) and secretion levels (P < 0.0001) of SERPINE2 were higher in OSCC than in the normal oral mucosa. According to the immunohistochemical analysis, SERPINE2 expression was correlated with the depth of invasion (P = 0.0163), nodal metastasis (P = 0.0085), microvessel density (P < 0.0001), and lymphovessel density (P < 0.0001). Additionally, univariate and multivariate analyses indicated that the SERPINE2 expression level was an independent poor prognostic factor for OSCC. In vitro studies using OSCC cells revealed that SERPINE2 promotes angiogenesis and lymphangiogenesis.

CONCLUSION

These results suggest that SRPX2 might be a useful tumor marker for OSCC.

High expression level of serpin peptidase inhibitor clade E member 2 is associated with poor prognosis in lung adenocarcinoma

Background

Recent studies have revealed that serpin peptidase inhibitor clade E member 2 (SERPINE2) is associated with tumorigenesis. However, SERPINE2 expression and its role in lung adenocarcinomas are still unknown.

Methods

The expression levels of SERPINE2 in 74 consecutively resected lung adenocarcinomas were analyzed by using immunostaining. Inhibition of SERPINE2 expression by small interfering RNA (siRNA) was detected by quantitative PCR. Cell number assays and cell apoptosis assays were performed to clarify the cell-autonomous function of SERPINE2 in A549 and PC9 lung cancer cells.

Results

The overall survival of patients with high SERPINE2 expression was significantly worse than that of patients with low SERPINE2 expression (P = 0.0172). Multivariate analysis revealed that SERPINE2 expression was an independent factor associated with poor prognosis (P = 0.03237). The interference of SERPINE2 decreased cell number and increased apoptosis in A549 and PC9 cells

Conclusion

These results suggest that SERPINE2 can be used as a novel prognostic marker of lung adenocarcinoma.

BAP31 Promotes Tumor Cell Proliferation by Stabilizing SERPINE2 in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) patients are mostly diagnosed at an advanced stage, resulting in systemic therapy and poor prognosis. Therefore, the identification of a novel treatment target for HCC is important. B-cell receptor-associated protein 31 (BAP31) has been identified as a cancer/testis antigen; however, BAP31 function and mechanism of action in HCC remain unclear. In this study, BAP31 was demonstrated to be upregulated in HCC and correlated with the clinical stage. BAP31 overexpression promoted HCC cell proliferation and colony formation in vitro and tumor growth in vivo. RNA-sequence (RNA-seq) analysis demonstrated that serpin family E member 2 (SERPINE2) was downregulated in BAP31-knockdown HCC cells. Coimmunoprecipitation and immunofluorescence assays demonstrated that BAP31 directly binds to SERPINE2. The inhibition of SERPINE2 significantly decreased the BAP31-induced cell proliferation and colony formation of HCC cells and phosphorylation of Erk1/2 and p38. Moreover, multiplex immunohistochemistry staining of the HCC tissue microarray showed positive associations between the expression levels of BAP31, SERPINE2, its downstream gene LRP1, and a tumor proliferation marker, Ki-67. The administration of anti-BAP31 antibody significantly inhibited HCC cell xenograft tumor growth in vivo. Thus, these findings suggest that BAP31 promotes tumor cell proliferation by stabilizing SERPINE2 and can serve as a promising candidate therapeutic target for HCC.

Contribution of the Low-Density Lipoprotein Receptor Family to Breast Cancer Progression

The low-density lipoprotein receptor (LDLR) family comprises 14 single-transmembrane receptors sharing structural homology and common repeats. These receptors specifically recognize and internalize various extracellular ligands either alone or complexed with membrane-spanning co-receptors that are then sorted for lysosomal degradation or cell-surface recovery. As multifunctional endocytic receptors, some LDLR members from the core family were first considered as potential tumor suppressors due to their clearance activity against extracellular matrix-degrading enzymes. LDLRs are also involved in pleiotropic functions including growth factor signaling, matricellular proteins, and cell matrix adhesion turnover and chemoattraction, thereby affecting both tumor cells and their surrounding microenvironment. Therefore, their roles could appear controversial and dependent on the malignancy state. In this review, recent advances highlighting the contribution of LDLR members to breast cancer progression are discussed with focus on (1) specific expression patterns of these receptors in primary cancers or distant metastasis and (2) emerging mechanisms and signaling pathways. In addition, potential diagnosis and therapeutic options are proposed.

Mini Review: Opposing Pathologies in Cancer and Alzheimer's Disease: Does the PI3K/Akt Pathway Provide Clues?

This minireview is a brief overview examining the roles of insulin-like growth factors (IGFs) and the PI3K/Akt pathway in two apparently unconnected diseases: Alzheimer's dementia and cancer. For both, increased age is a major risk factor, and, in accord with the global rise in average life expectancy, their prevalence is also increasing. Cancer, however, involves excessive cell proliferation and metastasis, whereas Alzheimer's disease (AD) involves cell death and tissue destruction. The apparent "inverse" nature of these disease states is examined here, but also some important commonalities in terms of the PI3K/Akt pathway, glucose utilization and cell deregulation/death. The focus here is on four key molecules associated with this pathway; notably, the insulin receptor substrate 1 (IRS-1), cellular tumor antigen p53 (p53), peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 (PIN1) and low-density lipoprotein receptor-related protein-1 (LRP1), all previously identified as potential therapeutic targets for both diseases. The insulin-resistant state, commonly reported in AD brain, results in neuronal glucose deprivation, due to a dampening down of the PI3K/Akt pathway, including overactivity of the mammalian target of rapamycin 1 (mTORC1) complex, hyperphosphorylation of p53 and neuronal death. This contrasts with cancer, where there is overstimulation of the PI3K/Akt pathway and the suppression of mTORC1 and p53, enabling abundant energy and unrestrained cell proliferation. Although these disease states appear to be diametrically opposed, the same key molecules are controlling pathology and, with differential targeting of therapeutics, may yet provide a beneficial outcome for both.

Novel Barbiturate-Nitrate Compounds Inhibit the Upregulation of Matrix Metalloproteinase-9 Gene Expression in Intestinal Inflammation through a cGMP-Mediated Pathway

Matrix metalloproteinase-9 is upregulated in inflammatory bowel disease. Barbiturate nitrate hybrid compounds have been designed to inhibit MMP secretion and enzyme activity. In this study, we investigated the mechanism of action of barbiturate-nitrate hybrid compounds and their component parts using models of intestinal inflammation in vitro. Cytokine-stimulated Caco-2 cells were used in all in vitro experiments. The NO donors SNAP and DETA-NONOate were used to study the effect of NO on MMP-9 mRNA. Mechanistic elucidation was carried out using the soluble guanylate cyclase (sGC) inhibitor, ODQ, and the cGMP analogue, 8-Bromo-cGMP. Further experiments were carried out to elucidate the role of NF-κB. NO donors exerted an inhibitory effect on MMP-9 mRNA in cytokine-stimulated cells. While the non-nitrate barbiturates had a limited effect on MMP-9 expression, the hybrid compounds inhibited MMP-9 expression through its NO-mimetic properties. No effect could be observed on mRNA for MMP-1 or MMP-2. The sGC inhibitior, ODQ, abolished the nitrate-barbiturate inhibition of MMP-9 gene expression, an effect which was reversed by 8-Br-cGMP. This study shows that the barbiturate scaffold is suitable for hybrid design as an MMP-9 inhibitor in cytokine-stimulated Caco-2 cells. The inhibition of MMP-9 levels was largely mediated through a reduction in its mRNA by a sGC/cGMP pathway mediated mechanism.

Macrophage M1/M2 polarization

Macrophages can be affected by a variety of factors to change their phenotype and thus affect their function. Activated macrophages are usually divided into two categories, M1-like macrophages and M2-like macrophages. Both M1 macrophages and M2 macrophages are closely related to inflammatory responses, among which M1 macrophages are mainly involved in pro-inflammatory responses and M2 macrophages are mainly involved in anti-inflammatory responses. Improving the inflammatory environment by modulating the activation state of macrophages is an effective method for the treatment of diseases. In this review, we analyzed the mechanism of macrophage polarization from the tumor microenvironment, nanocarriers, nuclear receptor PPARγ, phagocytosis, NF-κB signaling pathways, and other pathways.

SERPINE2 promotes esophageal squamous cell carcinoma metastasis by activating BMP4

Metastasis is a major lethal cause of esophageal squamous cell carcinoma (ESCC) and confers a poor prognosis. Previous studies demonstrated that serpin family E member 2 (SERPINE2) is involved in tumor metastasis. However, the function and mechanism of SERPINE2 in ESCC metastasis remains unclear. In this study, we found that SERPINE2 was increased in ESCC and associated with tumor metastasis. SERPINE2 knockdown inhibited tumor cell invasion and lymph node and lung metastasis by inducing epithelial-mesenchymal transition (EMT). We identified a total of 410 differentially expressed genes in SERPINE2-knockdown cells by RNA-Seq analysis. Among them, bone morphogenetic protein 4 (BMP4) was significantly downregulated. Conversely, BMP4 was increased in SERPINE2-overexpressing cells. Inhibiting BMP4 could attenuate SERPINE2-induced migration and invasion. Moreover, SERPINE2 was positively correlated with clinical stage, tumor invasion depth and lymph node metastasis in ESCC patients. These findings suggest that SERPINE2 promotes tumor metastasis by activating BMP4 and could serve as a potential therapeutic target for clinical intervention in ESCC.

Protease Nexin I is a feedback regulator of EGF/PKC/MAPK/EGR1 signaling in breast cancer cells metastasis and stemness

Breast cancer is the most prevalent cancer in women worldwide, which remains incurable once metastatic. Breast cancer stem cells (BCSCs) are a small subset of breast cancer cells, which are the radical cause of drug resistance, tumor relapse, and metastasis in breast cancer. The extracellular serine protease inhibitor serpinE2, also named protease nexin-1 (PN-1), contributes to enhanced metastasis of cancer cells mainly by remodeling the tumor matrix. In this study, we found that PN-1 was up-regulated in breast cancer, which promoted cell invasion, migration and stemness. Furthermore, by using specific inhibitors, we discovered that epidermal growth factor (EGF) up-regulated PN-1 in breast cancer cells through cascade activation of epidermal growth factor receptor (EGFR) to the activation of protein kinase Cδ (PKCδ), mitogen-activated protein kinase (MEK) and extracellular signal-related kinase (ERK), which finally led to the up-regulation of early growth response protein 1 (EGR1). Moreover, EGF signaling was further activated as a feedback of PN-1 up-regulation through PN-1 blocking HtrA1. Taken together, our findings revealed a novel signaling axis that up-regulated PN-1 expression in breast cancer cells, and the new mechanism of PN-1-promoted breast cancer metastasis, which may provide new insights into identifying novel therapeutic targets for breast cancer.

Emerging roles of low-density lipoprotein in the development and treatment of breast cancer

Breast cancer is a heterogeneous disease with increasing incidence and mortality and represents one of the most common cancer types worldwide. Low-density lipoprotein (LDL) is a complex particle composed of several proteins and lipids, which carries cholesterol into peripheral tissues and also affects the metabolism of fatty acids. Recent reports have indicated an emerging role of LDL in breast cancer, affecting cell proliferation and migration, thereby facilitating disease progression. However, controversy still exists among distinct types of breast cancer that can be affected by LDL. Classical therapeutic approaches, such as radiotherapy, chemotherapy, and lipid-lowering drugs were also reported as affecting LDL metabolism and content in breast cancer patients. Therefore, in this review we summarized and discussed the role of LDL in the development and treatment of breast cancer.

Evaluation of the developmental toxicity of 2,7-dibromocarbazole to zebrafish based on transcriptomics assay

Polyhalogenated carbazoles (PHCZs), which have the similar structure of dioxin, have been reported ubiquitous in the environments and drawn wide concerns. However, their potential ecological and health risks are still poorly understood. Here, wildtype zebrafish embryos were used to evaluate the environmental risks of 2,7-dibromocarbazole (2,7-DBCZ), 3,6-dibromocarbazole (3,6-DBCZ), and 3,6-dichlorocarbazole (3,6-DCCZ). 2,7-DBCZ was the most toxic compound with the 96-h LC₅₀ value of 581.8 ± 29.3 μg·L^-1 and the EC₅₀ value of 201.5 ± 6.5 μg·L^-1 for pericardial edema. The teratogenic effects of 2,7-DBCZ were tested using transgenic zebrafish larvae. The transcriptomic analysis revealed that 90 genes in zebrafish expressed differently after exposure to 2,7-DBCZ, and many pathways were related to aryl hydrocarbon receptor (AhR) activation. The qRT-PCR also showed that expression levels of AhR1 and CYP1 A in zebrafish were significantly up-regulated after exposure to 2,7-DBCZ. In conclusion, 2,7-DBCZ exhibited more potent toxicity and cardiac teratogenic effects, and presented developmental toxicity partially consistent with AhR activation. Our results will be of great help to the risk assessment and regulation-making of PHCZs. Meanwhile, further studies should be promoted to illustrate the potential mechanism between PHCZs and AhR in the near future.

Leukocyte-mimicking Pluronic-lipid nanovesicle hybrids inhibit the growth and metastasis of breast cancer

Breast cancer is a severe threat to the health of women, and the metastasis of tumor cells leads to high mortality in female patients. Evidence shows that leukocytes are recruited by breast tumors through adhesion to inflammatory endothelial cells as well as tumor cells. Moreover, it is known that Pluronic P123 is effective in the reduction of matrix metalloproteinases (MMPs), which play a key role in the degradation of the extracellular matrix (ECM), therefore helping tumor cells to escape from the primary site. Inspired by these mechanisms, we established a leukocyte-mimicking Pluronic-lipid nanovesicle hybrid (LPL) through integrating the membrane proteins extracted from leukocytes with membrane-like vesicles, with Pluronic P123 hybridized in the lipid bilayer, while paclitaxel (PTX) was selected as the model drug. The hybrid vesicles were perfectly incorporated with the leukocyte membrane proteins, and no disruption to the lipid membrane was caused by P123, with the bio-targeting ability of leukocytes and the MMP-9-downregulation effect of P123 fully preserved in LPL. LPL exhibited enhanced cellular uptake and anti-metastasis efficacy in in vitro assays, while significant tumor targeting capabilities were also found through biodistribution assays. Moreover, the in vivo therapeutic effects of PTX-loaded LPL (PTX-LPL) were observed, with an 80.84% inhibition rate of tumor growth and a 10.62% metastatic rate of tumor foci in lung tissue. Furthermore, the amounts of MMP-9 and neutrophils in the tumor as well as in the lung were greatly reduced with PTX-LPL. In summary, LPL may have potential applications in metastatic breast cancer therapy.

The fibrinolytic factor tPA drives LRP1-mediated melanoma growth and metastasis

The multifunctional endocytic receptor low-density lipoprotein receptor-related protein (LRP)1 has recently been identified as a hub within a biomarker network for multicancer clinical outcome prediction. The mechanism how LRP1 modulates cancer progression is poorly understood. In this study we found that LRP1 and one of its ligands, tissue plasminogen activator (tPA), are expressed in melanoma cells and control melanoma growth and lung metastasis in vivo. Mechanistic studies were performed on 2 melanoma cancer cell lines, B16F10 and the B16F1 cells, both of which form primary melanoma tumors, but only B16F10 cells metastasize to the lungs. Tumor-, but not niche cell-derived tPA, enhanced melanoma cell proliferation in tPA^-/- mice. Gain-of-function experiments revealed that melanoma LRP1 is critical for tumor growth, recruitment of mesenchymal stem cells into the tumor bed, and metastasis. Melanoma LRP1 was found to enhance ERK activation, resulting in increased matrix metalloproteinase (MMP)-9 RNA, protein, and secreted activity, a well-known modulator of melanoma metastasis. Restoration of LRP1 and tPA in the less aggressive, poorly metastatic B16F1 tumor cells enhanced tumor cell proliferation and led to massive lung metastasis in murine tumor models. Antimelanoma drug treatment induced tPA and LRP1 expression. tPA or LRP1 knockdown enhanced chemosensitivity in melanoma cells. Our results identify the tPA-LRP1 pathway as a key switch that drives melanoma progression, in part by modulating the cellular composition and proteolytic makeup of the tumor niche. Targeting this pathway may be a novel treatment strategy in combination treatments for melanoma.-Salama, Y., Lin, S.-Y., Dhahri, D., Hattori, K., Heissig, B. The fibrinolytic factor tPA drives LRP1-mediated melanoma growth and metastasis.

Overexpression of low density lipoprotein receptor-related protein 1 (LRP1) is associated with worsened prognosis and decreased cancer immunity in clear-cell renal cell carcinoma

AIM

Clear-cell renal cell carcinoma (ccRCC) is characterized with underlying genetic disorders and the role of low density lipoprotein receptor-related protein 1 (LRP1) in ccRCC is unknown.

METHOD

An in silico exploratory analysis using multiple public genetic datasets was used to establish association between LRP1 expression and clinicopathological parameters. Associations of interest were validated using 155 ccRCC samples using immunohistochemistry.

RESULTS

LRP1 was overexpressed in tumor compared with normal kidney tissue. Increased LRP1 expression in ccRCC was associated with advanced stage, grade and worsened overall survival and progression-free survival. Functional annotation indicated an immune-modulatory role of LRP1 in ccRCC. LRP1 expression was significantly correlated with expressions of PBRM1, SETD2, and KDM5C. Positive correlations between LRP1 and pro-angiogenic factors ERAP1, SCG2, STAB1, and RUNX1 were observed. LRP1 expression was positively correlated with PD-L2 level. Negative correlations between LRP1 and anti-angiogenic factors EMCN and IL18 were observed. LRP1 expression was not associated with microvessel density (MVD) yet was negatively correlated with tumor-infiltrating lymphocytes (TIL).

CONCLUSION

LRP1 is associated with worsened prognosis in ccRCC and is related to cancer immune modulation. LRP1-targeted therapy can be of therapeutic potential.

Synergistically Enhanced Antimetastasis Effects by Honokiol-Loaded pH-Sensitive Polymer-Doxorubicin Conjugate Micelles

In an effort to prevent metastasis of breast tumor cells- at the same time of inhibiting tumor growth with less toxic side effects, honokiol (HNK) was encapsulated into pH-sensitive polymeric micelles based on the conjugate of poly(2-ethyl-2-oxazoline)-poly(d,l-lactide) (PEOz-PLA) with doxorubicin (DOX), denoted as PEOz-PLA-imi-DOX. PEOz-PLA-imi-DOX was successfully synthesized by connecting DOX to the hydrophobic end of PEOz-PLA via acid-cleavable benzoic imine linker. HNK-loaded conjugate micelles (HNK/PP-DOX-PM) with a size of 21 nm and homogeneous spherical shape exhibited high drug-loading capacity. PEOz-PLA-imi-DOX and HNK/PP-DOX-PM displayed faster release of DOX at pH 5.0 than at pH 7.4. As anticipated, PEOz-PLA-imi-DOX maintained cytotoxicity of DOX against MDA-MB-231 cells. The synergistically enhanced in vitro antitumor effect of HNK/PP-DOX-PM was confirmed by their synergetic inhibition of MDA-MB-231 cell growth. Furthermore, the efficient prevention of tumor metastasis by HNK/PP-DOX-PM was testified by in vitro anti-invasion, wound healing and antimigration assessment in MDA-MB-231 cells, and in vivo bioluminescence imaging in nude mice. The suppression of growth and metastasis of tumor cells by HNK/PP-DOX-PM was attributed to the synergistic effect of pH-triggered drug release and HNK-aroused inhibition of matrix metalloproteinases and epithelial-mesenchymal transition, respectively. In addition, HNK/PP-DOX-PM exhibited superior biosafety than physically encapsulated dual-drug micelles. Consequently, the fabricated HNK/PP-DOX-PM may have great potential for safe and effective suppression of tumor growth and metastasis.

pH Responsive Polymer Micelles Enhances Inhibitory Efficacy on Metastasis of Murine Breast Cancer Cells

A pH sensitive micellar cargo was fabricated for pH triggered delivery of hydrophobic drug paclitaxel with pH controlled drug release profiles. The size, drug loading content, and encapsulation efficiency of PTX loaded micelles were 20-30 nm, 7.5%, 82.5%, respectively. PTX loaded PELA-PBAE micelles could enhance the intracellular uptake of a model drug significantly, with increased cytotoxicity and inhibition of tumor metastasis on 4T1 cells, as confirmed by wound healing assay and tumor cells invasion assay. The expression of metastasis and apoptosis correlated proteins on 4T1 cells decreased remarkably after intervention by PTX loaded polymer micelles, as demonstrated by western blotting and quantitative reverse transcriptional-polymerase chain reaction (qRT-PCR). Our results demonstrated the pH responsive polymer micelles might have the potential to be used in the treatment of metastatic breast tumors.

ZEB1-repressed microRNAs inhibit autocrine signaling that promotes vascular mimicry of breast cancer cells

During normal tumor growth and in response to some therapies, tumor cells experience acute or chronic deprivation of nutrients and oxygen and induce tumor vascularization. While this occurs predominately through sprouting angiogenesis, tumor cells have also been shown to directly contribute to vessel formation through vascular mimicry (VM) and/or endothelial transdifferentiation. The extrinsic and intrinsic mechanisms underlying tumor cell adoption of endothelial phenotypes, however, are not well understood. Here we show that serum withdrawal induces mesenchymal breast cancer cells to undergo VM and that knockdown of the epithelial-to-mesenchymal transition (EMT) regulator, Zinc finger E-box binding homeobox 1 (ZEB1), or overexpression of the ZEB1-repressed microRNAs (miRNAs), miR-200c, miR-183, miR-96 and miR-182 inhibits this process. We find that secreted proteins Fibronectin 1 (FN1) and serine protease inhibitor (serpin) family E member 2 (SERPINE2) are essential for VM in this system. These secreted factors are upregulated in mesenchymal cells in response to serum withdrawal, and overexpression of VM-inhibiting miRNAs abrogates this upregulation. Intriguingly, the receptors for these secreted proteins, low-density lipoprotein receptor-related protein 1 (LRP1) and Integrin beta 1 (ITGB1), are also targets of the VM-inhibiting miRNAs, suggesting that autocrine signaling stimulating VM is regulated by ZEB1-repressed miRNA clusters. Together, these data provide mechanistic insight into the regulation of VM and suggest that miRNAs repressed during EMT, in addition to suppressing migratory and stem-like properties of tumor cells, also inhibit endothelial phenotypes of breast cancer cells adopted in response to a nutrient-deficient microenvironment.

Serpin E2 promotes breast cancer metastasis by remodeling the tumor matrix and polarizing tumor associated macrophages

The extracellular serine protease inhibitor serpinE2 is overexpressed in breast cancer and has been shown to foster metastatic spread. Here, we investigated the hypothesis that serpinE2 creates tumor-promoting conditions in the tumor microenvironment (TME) by affecting extracellular matrix remodeling. Using two different breast cancer models, we show that blocking serpinE2, either by knock-down (KD) in tumor cells or in response to a serpinE2 binding antibody, decreases metastatic dissemination from primary tumors to the lungs. We demonstrate that in response to serpinE2 KD or antibody treatment there are dramatic changes in the TME. Multiphoton intravital imaging revealed deposition of a dense extracellular collagen I matrix encapsulating serpinE2 KD or antibody-treated tumors. This is accompanied by a reduction in the population of tumor-promoting macrophages, as well as a decrease in chemokine ligand 2, which is known to affect macrophage abundance and polarization. In addition, TIMP-1 secretion is increased, which may directly inhibit matrix metalloproteases critical for collagen degradation in the tumor. In summary, our findings suggest that serpinE2 is required in the extracellular milieu of tumors where it acts in multiple ways to regulate tumor matrix deposition, thereby controlling tumor cell dissemination.

Expression pattern of human SERPINE2 in a variety of human tumors

Serine proteinase inhibitor, clade E member 2 (SERPINE2), also known as protease nexin-1 (PN-1), is a member of the serpin family. Despite several reported roles of SERPINE2 in tumor development the histological distribution of SERPINE2 and its expression levels in a large variety of tumors remains unclear. Through expressed sequence tag database analysis, immunohistochemical staining of tissue microarrays and a literature review, it was revealed that SERPINE2 expression varied according to growth stages and tissue types. SERPINE2 is differentially expressed in a number of tumors and their normal tissue counterparts. SERPINE2 is identified most abundantly in adenocarcinomas. SERPINE2 serves diverse roles in a variety of tumors and therefore may serve as a promising biomarker for tumor diagnosis and prognosis.

A slow-cycling subpopulation of melanoma cells with highly invasive properties

Melanoma is a heterogeneous tumor with different subpopulations showing different proliferation rates. Slow-cycling cells were previously identified in melanoma, but not fully biologically characterized. Using the label-retention method, we identified a subpopulation of slow-cycling cells, defined as label-retaining cells (LRC), with strong invasive properties. We demonstrate through live imaging that LRC are leaving the primary tumor mass at a very early stage and disseminate to peripheral organs. Through global proteome analyses, we identified the secreted protein SerpinE2/protease nexin-1 as causative for the highly invasive potential of LRC in melanomas.

The Kunitz Domain I of Hepatocyte Growth Factor Activator Inhibitor-2 Inhibits Matriptase Activity and Invasive Ability of Human Prostate Cancer Cells

Dysregulation of pericellular proteolysis is often required for tumor invasion and cancer progression. It has been shown that down-regulation of hepatocyte growth factor activator inhibitor-2 (HAI-2) results in activation of matriptase (a membrane-anchored serine protease), human prostate cancer cell motility and tumor growth. In this study, we further characterized if HAI-2 was a cognate inhibitor for matriptase and identified which Kunitz domain of HAI-2 was required for inhibiting matriptase and human prostate cancer cell motility. Our results show that HAI-2 overexpression suppressed matriptase-induced prostate cancer cell motility. We demonstrate that HAI-2 interacts with matriptase on cell surface and inhibits matriptase proteolytic activity. Moreover, cellular HAI-2 harnesses its Kunitz domain 1 (KD1) to inhibit matriptase activation and prostate cancer cell motility although recombinant KD1 and KD2 of HAI-2 both show an inhibitory activity and interaction with matriptase protease domain. The results together indicate that HAI-2 is a cognate inhibitor of matriptase, and KD1 of HAI-2 plays a major role in the inhibition of cellular matritptase activation as well as human prostate cancer invasion.

Concurrently suppressing multidrug resistance and metastasis of breast cancer by co-delivery of paclitaxel and honokiol with pH-sensitive polymeric micelles

To concurrently suppress multidrug resistance (MDR) and metastasis of breast cancer cells, paclitaxel (PTX) and honokiol (HNK) were coencapsulated into pH-sensitive polymeric micelles based on poly(2-ethyl-2-oxazoline)-poly(d,l-lactide) (PEOz-PLA). The physicochemical properties of dual drug-loaded PEOz-PLA micelles were characterized in size, drug loading and in vitro release. The efficiency of MDR reversal for the micelles was testified by synergetic enhancement of cytotoxicity and uptake by MCF-7/ADR cells. The flow cytometry and fluorescence polarization measurement results reinforced the conclusion that down-regulation of P-gp expression and increase of plasma membrane fluidity appeared to be possible mechanisms of MDR reversal by dual drug-loaded PEOz-PLA micelles. Further, the efficient inhibition of tumor metastasis by dual drug-loaded PEOz-PLA micelles was demonstrated by in vitro anti-invasion and anti-migration assessment in MDA-MB-231 cells and in vivo bioluminescence imaging in nude mice. The suppression of MDR and metastasis by the micelles was assigned to synergistic effects of pH-triggered drug release and HNK/PEOz-PLA-aroused P-gp inhibition, and pH-triggered drug release and PTX/HNK-aroused MMPs inhibition, respectively. In conclusion, our findings strengthen the usefulness of co-delivery of PTX and HNK by pH-responsive polymeric micelles for suppression of tumor MDR and metastasis.

STATEMENT OF SIGNIFICANCE

Multidrug resistance (MDR) and metastasis are considered to be two of the major barriers for successful chemotherapy. The combination of a chemotherapeutic drug with a modulator has emerged as a promising strategy for efficiently treating MDR cancer and preventing tumor metastasis. Herein, a dual drug (paclitaxel and honokiol)-loaded pH-sensitive polymeric micelle system based on PEOz-PLA was successfully fabricated to ensure that tumor MDR and metastasis could be concurrently suppressed, therefore achieving distinguishing endo/lysosomal pH from physiological pH by accelerating drug release and then enhancing the cytotoxicity of paclitaxel to drug-resistant tumor cells MCF-7/ADR by increasing cellular uptake of paclitaxel, preventing in vitro invasion and migration for MDA-MB-231 cells and in vivo metastasis in nude mice. Further, the mechanism of MDR reversal by dual drug-loaded PEOz-PLA micelles was elucidated to be down-regulation of P-gp expression and increase of plasma membrane fluidity of MCF-7/ADR cells. The present findings strengthen the usefulness of co-delivery of PTX and HNK by pH-responsive polymeric micelles for suppression of tumor MDR and metastasis.

Identification of Nucleobindin-2 as a Potential Biomarker for Breast Cancer Metastasis Using iTRAQ-based Quantitative Proteomic Analysis

Metastasis is a lethal step in the progression of breast cancer. None of the metastasis-associated biomarkers identified up to now has a definite prognostic value in breast cancer patients. This study was designed to identify biomarkers for breast cancer metastasis and predictors of the prognosis of breast cancer patients. The differentially expressed proteins between 23 paired primary breast tumor and metastatic lymph nodes were identified by quantitative iTRAQ proteomic analysis. Immunohistochemistry was applied to locate and assess the expression of NUCB2 in paired primary breast tumor and metastatic lymph node tissues (n = 106). The relationship between NUCB2 expression and the clinicopathological characteristics of breast cancer patients (n = 189) were analyzed by χ² test. Kaplan-Meier analysis and Cox hazard regression analysis were utilized to investigate the relationship between its expression and prognosis of breast cancer patients. The iTRAQ proteomic results showed that 4,837 confidential proteins were identified, 643 of which were differentially expressed in the primary breast cancer tissues and the paired metastatic lymph nodes. NUCB2 protein was found decreased in paired metastatic lymph nodes (P = 0.000), with the positive expression rate being 82% in primary breast cancer tissues and 47% in paired metastatic lymph nodes, respectively. According to Kaplan-Meier analysis, the overall survival time of patients with positive expression of NUCB2 protein were shorter than those with negative NUCB2 expression (P = 0.004). Cox regression model suggested that NUCB2 was a risk factor of breast cancer patients (P = 0.045, RR = 1.854). We conclude that NUCB2 can be used as a potential biomarker for breast cancer metastasis and a prognostic predictor of breast cancer patients.