Six-transmembrane epithelial antigen of the prostate 1 expression promotes ovarian cancer metastasis by aiding progression of epithelial-to-mesenchymal transition.

Ovarian cancer is a severe malignant tumour of the female genital organs. Six-transmembrane epithelial antigen of the prostate 1 (STEAP1) expression is correlated with the occurrence and progression of multiple cancers. Here, we assessed STEAP1 expression in ovarian cancer and explored the relationship between STEAP1 and ovarian cancer progression. We used immunohistochemistry and public databases to test STEAP1 expression in normal human ovarian tissues, benign ovarian tumours, and ovarian cancer. The expression of STEAP1 and epithelial-to-mesenchymal transition (EMT)-related genes was analysed using immunocytochemistry, quantitative reverse transcription polymerase chain reaction, and western blotting in ovarian cancer cell lines. Lentivirus was used to knockdown and overexpress STEAP1. Invasion, migration, growth, clonogenicity, and apoptosis were assessed using transwell assay, growth curve, plate clone formation assay, and flow cytometry. We used a tumour xenograft to verify the relationship between STEAP1 and in vivo ovarian cancer cell growth. Matrix metalloproteinase-2 (MMP2) and matrix metalloproteinase-9 (MMP9) activities were examined using Matrix metalloproteinase zymography assay. STEAP1 was highly expressed in the human ovarian cancer tissues and a highly invasive ovarian cancer cell line. Overexpression of STEAP1 was related to poor prognosis in ovarian cancer patients. Down-regulation of STEAP1 suppressed the invasion, migration, proliferation, clonogenicity, EMT progression in human ovarian cancer cells and xenograft tumour growth in vivo, but it enhanced apoptosis. In human ovarian cancer, the STEAP1 gene is highly expressed, and its function is correlated with human ovarian cancer cell metastasis and growth. STEAP1 may be a possible target for suppressing ovarian cancer metastasis.

Platelet membrane-coated nanoparticles for targeted drug delivery and local chemo-photothermal therapy of orthotopic hepatocellular carcinoma.

Specific targeted drug delivery and controllable release of drugs at tumor regions are two of the main challenges for hepatocellular carcinoma (HCC) therapy, particularly post metastasis. Herein, we present a platelet membrane-facilitated local chemo-photothermal therapy strategy, in which polypyrrole (PPy) nanoparticles act as photothermal agents and along with antitumor drug doxorubicin (DOX) are encapsulated into platelet membranes (PLT-PPy-DOX). The particles are endowed with immune evasiveness and tumor targeting abilities from platelet membranes, and are then intravenously injected into an orthotopic mouse model of HCC. As expected, the PLT-PPy-DOX nanoplatforms were abundant in the tumor tissues. Hyperthermia was generated under laser irradiation (808 nm) not only to ablate tumor cells directly but also to increase the triggered release of DOX. This combination of local chemotherapy and photothermal therapy demonstrated excellent antitumor efficiency in suppressing primary tumor growth and inhibiting tumor metastases. This localized therapy which adopts biocompatible natural cell membranes and good biodegradable organic photothermal agents may provide new insights into designing biomimetic nano-vehicles for personalized therapy of HCC.

Low-dose paclitaxel via hyaluronan-functionalized bovine serum albumin nanoparticulate assembly for metastatic melanoma treatment.

Due to the critical role of CD44 in mediating cell adhesion and migration, CD44-targeted drug delivery via hyaluronan has been extensively explored. Herein, cationic bovine serum albumin nanoparticles were assembled with hyaluronan (HA) of various molecular weights via simple electrostatic interaction to afford hierarchical nanoparticles (HNPs) with various size distributions and structures. Next, HNPs obtained using 49 kDa HA have been used to encapsulate paclitaxel (PTX-HNPs), which demonstrated selective lung accumulation due to both size effect and CD44-mediated targetability. Biodistribution studies showed that HNPs enhanced the lung specific accumulation of HNPs in the C57BL/6 mice melanoma lung metastasis model. In the antitumor studies, compared with the Taxol or bovine serum albumin nanoparticle (NP) groups, PTX-HNPs significantly inhibited B16F10 lung metastasis at a relatively low dose. Additionally, cell migration and invasion experiments in vitro further confirmed that PTX-HNPs significantly inhibited the migration of B16F10 cells compared to Taxol or paclitaxel-loaded NP groups. Overall, our results suggest that PTX-HNPs represent a highly promising strategy for the treatment of lung metastatic melanoma.

Amide-sulfamide modulators as effective anti-tumor metastatic agents targeting CXCR4/CXCL12 axis.

Breast cancer is the most frequently diagnosed malignancy and the second common cause of death in women worldwide. High mortality in breast cancer is frequently associated with metastatic progression rather than the primary tumor itself. It has been recently identified that the CXCR4/CXCL12 axis plays a pivotal role in breast cancer metastasis, especially in directing metastatic cancer cells to CXCL12-riched organs and tissues. Herein, taking the amide-sulfamide as the lead structure, the second-round structural modifications to the sulfamide structure were performed to obtain more active CXCR4 modulators against tumor metastasis. Both in vivo and in vitro experiments illustrated that compound IIIe possessed potent CXCR4 binding affinity, excellent anti-metastatic and anti-angiogenetic activity against breast cancer. More importantly, in a mouse breast cancer lung metastasis model, compound IIIe exerted a significant inhibitory effect on breast cancer metastasis. Taken together, all these positive results demonstrated that developing of CXCR4 modulators is a promising strategy to mediate breast cancer metastasis.

Simple and robust polymer-based sensor for rapid cancer detection using serum.

We report a polymer-based sensor that rapidly detects cancer based on changes in serum protein levels. Using three ratiometric fluorescence outputs, this simple system identifies early stage and metastatic lung cancer with a high level of accuracy exceeding many biomarker-based assays, making it an attractive strategy for point-of-care testing.

Bone-Targeted Nanoplatform Combining Zoledronate and Photothermal Therapy To Treat Breast Cancer Bone Metastasis.

Bone metastasis, a clinical complication of patients with advanced breast cancer, seriously reduces the quality of life. To avoid destruction of the bone matrix, current treatments focus on inhibiting the cancer cell growth and the osteoclast activity through combination therapy. Therefore, it could be beneficial to develop a bone-targeted drug delivery system to treat bone metastasis. Here, a bone-targeted nanoplatform was developed using gold nanorods enclosed inside mesoporous silica nanoparticles (Au@MSNs) which were then conjugated with zoledronic acid (ZOL). The nanoparticles (Au@MSNs-ZOL) not only showed bone-targeting ability in vivo but also inhibited the formation of osteoclast-like cells and promoted osteoblast differentiation in vitro. The combination of Au@MSNs-ZOL and photothermal therapy (PTT), triggered by near-infrared irradiation, inhibited tumor growth both in vitro and in vivo and relieved pain and bone resorption in vivo by inducing apoptosis in cancer cells and improving the bone microenvironment. This single nanoplatform combines ZOL and PTT to provide an exciting strategy for treating breast cancer bone metastasis.

Dual-active targeting liposomes drug delivery system for bone metastatic breast cancer: Synthesis and biological evaluation.

Bone is the most common organ affected by metastatic breast cancer. Targeting cancers within the bone remains a great challenge due to the inefficient delivery of therapeutic to bone. In order to increase the distribution of paclitaxel (PTX) in bone metastases, in this study, a novel bone-targeted glutamic oligopeptides-RGD peptide (Glu6-RGD) derivative was designed and synthesized as liposome ligand for preparing liposome to effectively deliver PTX to bone metastases. The liposome was prepared and its particle size, zeta potential, encapsulation efficiency, release profile, stability, hemolysis and cytotoxicity were also characterized. What's more, the Glu6-RGD-Lip showed superior targeting ability in vitro and in vivo evaluation as compared to naked PTX, non-coated, singly-modified and co-modified by physical blending liposomes. All the results suggested that Glu6-RGD-modified liposome showed excellent targeting activity to metastatic bone cancer. This study may be conducive to the field of bone-targeting drugs delivery.

Unresolved endoplasmic reticulum stress engenders immune-resistant, latent pancreatic cancer metastases.

The majority of patients with pancreatic ductal adenocarcinoma (PDA) develop metastatic disease after resection of their primary tumor. We found that livers from patients and mice with PDA harbor single disseminated cancer cells (DCCs) lacking expression of cytokeratin 19 (CK19) and major histocompatibility complex class I (MHCI). We created a mouse model to determine how these DCCs develop. Intraportal injection of immunogenic PDA cells into preimmunized mice seeded livers only with single, nonreplicating DCCs that were CK19- and MHCI- The DCCs exhibited an endoplasmic reticulum (ER) stress response but paradoxically lacked both inositol-requiring enzyme 1α activation and expression of the spliced form of transcription factor XBP1 (XBP1s). Inducible expression of XBP1s in DCCs, in combination with T cell depletion, stimulated the outgrowth of macrometastatic lesions that expressed CK19 and MHCI. Thus, unresolved ER stress enables DCCs to escape immunity and establish latent metastases.

Adaptor protein p62 promotes skin tumor growth and metastasis and is induced by UVA radiation.

Skin cancer is the most common cancer, and exposure to ultraviolet (UV) radiation, namely UVA and UVB, is the major risk factor for skin cancer development. UVA is significantly less effective in causing direct DNA damage than UVB, but UVA has been shown to increase skin cancer risk. The mechanism by which UVA contributes to skin cancer remains unclear. Here, using RNA-Seq, we show that UVA induces autophagy and lysosomal gene expression, including the autophagy receptor and substrate p62. We found that UVA activates transcription factor EB (TFEB), a known regulator of autophagy and lysosomal gene expression, which, in turn, induces p62 transcription. Next, we identified a novel relationship between p62 and cyclooxygenase-2 (COX-2), a prostaglandin synthase critical for skin cancer development. COX-2 expression was up-regulated by UVA-induced p62, suggesting that p62 plays a role in UVA-induced skin cancer. Moreover, we found that p62 stabilizes COX-2 protein through the p62 ubiquitin-associated domain and that p62 regulates prostaglandin E2 production in vitro In a syngeneic squamous cell carcinoma mouse model, p62 knockdown inhibited tumor growth and metastasis. Furthermore, p62-deficient tumors exhibited reduced immune cell infiltration and increased cell differentiation. Because prostaglandin E2 is known to promote pro-tumorigenic immune cell infiltration, increase proliferation, and inhibit keratinocyte differentiation in vivo, this work suggests that UVA-induced p62 acts through COX-2 to promote skin tumor growth and progression. These findings expand our understanding of UVA-induced skin tumorigenesis and tumor progression and suggest that targeting p62 can help prevent or treat UVA-associated skin cancer.

A novel 3D in vitro metastasis model elucidates differential invasive strategies during and after breaching basement membrane.

Invasive breast cancer and other tumors of epithelial origin must breach a layer of basement membrane (BM) that surrounds the primary tumor before invading into the adjacent extracellular matrix. To analyze invasive strategies of breast cancer cells during BM breaching and subsequent invasion into a collagen I-rich extracellular matrix (ECM), we developed a physiologically relevant 3D in vitro model that recreates the architecture of a solid tumor with an intact, degradable, cell-assembled BM layer embedded in a collagen I environment. Using this model we demonstrate that while the BM layer fully prevents dissemination of non-malignant cells, cancer cells are capable of breaching it and invading into the surrounding collagen, indicating that the developed system recreates a hallmark of invasive disease. We demonstrate that cancer cells exhibiting individual invasion in collagen matrices preferentially adopt a specific mode of collective invasion when transmigrating a cell-assembled BM that is not observed in any other tested fibrillar, non-fibrillar, or composite ECM. Matrix-degrading enzymes are found to be crucial during BM breaching but not during subsequent invasion in the collagen matrix. It is further shown that multicellular transmigration of the BM is less susceptible to pharmacological MMP inhibition than multicellular invasion in composite collagen/basement membrane extract matrices. The newly developed in vitro model of metastasis allows 3D cancer cell invasion to be studied not only as a function of a particular tumor's genetics but also as a function of its heterogeneous environment and the different stages of invasion. As such, this model is a valuable new tool with which to dissect basic mechanisms of invasion and metastasis and develop new therapeutic approaches in a physiologically relevant, yet inexpensive and highly tunable, in vitro setting.

Fibrotic microenvironment promotes the metastatic seeding of tumor cells via activating the fibronectin 1/secreted phosphoprotein 1-integrin signaling.

The seeding of tumor cells is a critical step in the process of metastasis, but whether and how the microenvironment of target organs affects metastatic seeding remain largely unknown. Based on cell and mouse models, we found that the metastatic seeding and outgrowth of tumor cells were significantly enhanced in fibrotic lungs. The conditioned medium from both fibrotic lungs and the fibrotic lung-derived fibroblasts (CM-FLF) had a strong activity to chemoattract tumor cells and to inhibit the apoptosis of tumor cells. Subsequent investigations revealed that the levels of fibronectin 1 (FN1) and secreted phosphoprotein 1 (SPP1) were significantly increased in fibrotic lungs. Silencing of FN1 in the fibrotic lung-derived fibroblasts dramatically decreased the chemoattracting activity of CM-FLF, while silencing of FN1 or SPP1 in fibroblasts attenuated the anti-apoptosis activity of CM-FLF. Moreover, the CM-FLF-induced apoptosis resistance or chemotaxis of tumor cells was attenuated when ITGAV, the common receptor of FN1 and SPP1, was silenced by RNA interference or blocked by GRGDS treatment in tumor cells. Consistently, ITGAV silencing or GRGDS treatment significantly inhibited the seeding and outgrowth of tumor cells in fibrotic lungs in vivo. Collectively, we suggest that fibrotic microenvironment may enhance the metastatic seeding of tumor cells in the lung by chemoattracting tumor cells and inhibiting their apoptosis via activating the FN1/SPP1-ITGAV signaling. These findings give a novel insight into the regulatory mechanisms of cancer metastasis and provide a potential target for anti-metastasis therapy.

Inositol Hexaphosphate and Inositol Inhibit Colorectal Cancer Metastasis to the Liver in BALB/c Mice.

Inositol hexaphosphate (IP6) and inositol (Ins), naturally occurring carbohydrates present in most mammals and plants, inhibit the growth of numerous cancers both in vitro and in vivo. In this study, we first examined the anti-metastatic effects of IP6 and Ins using a liver metastasis model of colorectal cancer (CRC) in BALB/c mice. CT-26 cells were injected into the splenic capsule of 48 BALB/c mice. The mice were then randomly divided into four groups: IP6, Ins, IP6 + Ins and normal saline control (n = 12 per group). IP6 and/or Ins (80 mg/kg each, 0.2 mL/day) were injected into the gastrointestinal tracts of the mice on the second day after surgery. All mice were sacrificed after 20 days, and the tumor inhibition rates were determined. The results demonstrated that the tumor weights of liver metastases and the tumor inhibition rates were reduced in the experimental groups compared to the control group and that treatment with the combination of IP6 and Ins resulted in greater inhibition of tumor growth than treatment with either compound alone. These findings suggest that IP6 and Ins prevent the development and metastatic progression of colorectal cancer to the liver in mice by altering expression of the extracellular matrix proteins collagen IV, fibronectin and laminin; the adhesion factor receptor integrin-ß1; the proteolytic enzyme matrix metalloproteinase 9; and the angiogenic factors vascular endothelial growth factor, basic fibroblast growth factor, and transforming growth factor beta in the tumor metastasis microenvironment. In conclusion, IP6 and Ins inhibited the development and metastatic progression of colorectal cancer to the liver in BALB/c mice, and the effect of their combined application was significantly greater than the effect of either compound alone. This evidence supports further testing of the combined application of IP6 and Ins for the prevention of colorectal cancer metastasis to the liver in clinical studies.

Self-targeting of TNF-releasing cancer cells in preclinical models of primary and metastatic tumors.

Circulating cancer cells can putatively colonize distant organs to form metastases or to reinfiltrate primary tumors themselves through a process termed "tumor self-seeding." Here we exploit this biological attribute to deliver tumor necrosis factor alpha (TNF), a potent antitumor cytokine, directly to primary and metastatic tumors in a mechanism that we have defined as "tumor self-targeting." For this purpose, we genetically engineered mouse mammary adenocarcinoma (TSA), melanoma (B16-F10), and Lewis lung carcinoma cells to produce and release murine TNF. In a series of intervention trials, systemic administration of TNF-expressing tumor cells was associated with reduced growth of both primary tumors and metastatic colonies in immunocompetent mice. We show that these malignant cells home to tumors, locally release TNF, damage neovascular endothelium, and induce massive cancer cell apoptosis. We also demonstrate that such tumor-cell-mediated delivery avoids or minimizes common side effects often associated with TNF-based therapy, such as acute inflammation and weight loss. Our study provides proof of concept that genetically modified circulating tumor cells may serve as targeted vectors to deliver anticancer agents. In a clinical context, this unique paradigm represents a personalized approach to be translated into applications potentially using patient-derived circulating tumor cells as self-targeted vectors for drug delivery.

In vivo sensing of proteolytic activity with an NSET-based NIR fluorogenic nanosensor.

Biomedical in vivo sensing methods in the near-infrared (NIR) range, which that provide relatively high photon transparency, separation from auto-fluorescence background, and extended sensitivity, are being used increasingly for non-invasive mapping and monitoring of molecular events in cancer cells. In this study, we fabricated an NIR fluorogenic nanosensor based on the nanoparticle surface energy transfer effect, by conjugation of fluorescent proteolytic enzyme-specific cleavable peptides with gold nanorods (GNRs). Membrane-anchored membrane type 1-matrix metalloproteinases (MT1-MMPs), a family of zinc-dependent proteolytic enzymes, can induce the metastatic potential of cancer cells by promoting degradation of the extracellular matrix. Therefore, sensitive detection of MT1-MMP activity can provide essential information in the clinical setting. We have applied in vivo NIR sensing to evaluate MT1-MMP activity, as an NIR imaging target, in an MT1-MMP-expressing metastatic tumor mouse model.

In situ vaccination with cowpea mosaic virus nanoparticles suppresses metastatic cancer.

Nanotechnology has tremendous potential to contribute to cancer immunotherapy. The 'in situ vaccination' immunotherapy strategy directly manipulates identified tumours to overcome local tumour-mediated immunosuppression and subsequently stimulates systemic antitumour immunity to treat metastases. We show that inhalation of self-assembling virus-like nanoparticles from cowpea mosaic virus (CPMV) reduces established B16F10 lung melanoma and simultaneously generates potent systemic antitumour immunity against poorly immunogenic B16F10 in the skin. Full efficacy required Il-12, Ifn-γ, adaptive immunity and neutrophils. Inhaled CPMV nanoparticles were rapidly taken up by and activated neutrophils in the tumour microenvironment as an important part of the antitumour immune response. CPMV also exhibited clear treatment efficacy and systemic antitumour immunity in ovarian, colon, and breast tumour models in multiple anatomic locations. CPMV nanoparticles are stable, nontoxic, modifiable with drugs and antigens, and their nanomanufacture is highly scalable. These properties, combined with their inherent immunogenicity and demonstrated efficacy against a poorly immunogenic tumour, make CPMV an attractive and novel immunotherapy against metastatic cancer.

Animal models of human colorectal cancer: Current status, uses and limitations.

AIM: To make orthotopic colon cancer murine models a more clearly understood subject. The orthotopic tumor models have been found to be more relevant in replicating the human disease process as compared to heterotopic models, many techniques for making orthotopic colorectal murine models have been reported. METHODS: We evaluated the current literature for various reported orthotopic colon cancer models to understand their techniques, advantages and limitations. An extensive literature review was performed by searching the National Library of Medicine Database (PubMed) using MeSH terms animal model; colon cancer; orthotopic model; murine model. Twenty studies related to colon cancer orthotopic xenograft model were evaluated in detail and discussed here. RESULTS: The detailed analysis of all relevant reports on orthotopic model showed tumor take rate between 42%-100%. While models using the enema technique and minimally invasive technique have reported development of tumor from mucosa with tumor take rate between 87%-100% with metastasis in 76%-90%. CONCLUSION: Over the years, the increased understanding of the murine models of human colon cancer has resulted in the development of various models. Each reported model has some limitations. These latest models have opened up new doors for continuing cancer research for not only understanding the colon cancer pathogenesis but also aid in the development of newer chemotherapeutic drugs as they mimic the human disease closely.

Patrolling monocytes control tumor metastasis to the lung.

The immune system plays an important role in regulating tumor growth and metastasis. Classical monocytes promote tumorigenesis and cancer metastasis, but how nonclassical "patrolling" monocytes (PMo) interact with tumors is unknown. Here we show that PMo are enriched in the microvasculature of the lung and reduce tumor metastasis to lung in multiple mouse metastatic tumor models. Nr4a1-deficient mice, which specifically lack PMo, showed increased lung metastasis in vivo. Transfer of Nr4a1-proficient PMo into Nr4a1-deficient mice prevented tumor invasion in the lung. PMo established early interactions with metastasizing tumor cells, scavenged tumor material from the lung vasculature, and promoted natural killer cell recruitment and activation. Thus, PMo contribute to cancer immunosurveillance and may be targets for cancer immunotherapy.

Bone metastasis treatment using magnetic resonance-guided high intensity focused ultrasound.

OBJECTIVES: Bone pain resulting from cancer metastases reduces a patient's quality of life. Magnetic Resonance-guided High Intensity Focused Ultrasound (MR-HIFU) is a promising alternative palliative thermal treatment technique for bone metastases that has been tested in a few clinical studies. Here, we describe a comprehensive pre-clinical study to investigate the effects, and efficacy of MR-HIFU ablation for the palliative treatment of osteoblastic bone metastases in rats. MATERIALS AND METHODS: Prostate cancer cells (MATLyLu) were injected intra-osseously in Copenhagen rats. Upon detection of pain, as determined with a dynamic weight bearing (DWB) system, a MR-HIFU system was used to thermally ablate the bone region with tumor. Treatment effect and efficacy were assessed using magnetic resonance imaging (MRI), single-photon emission computed tomography (SPECT) with technetium-99m medronate ((99m)Tc-MDP), micro-computed tomography (µCT) and histology. RESULTS: DWB analysis demonstrated that MR-HIFU-treated animals retained 58.6 ± 20.4% of limb usage as compared to 2.6 ± 6.3% in untreated animals (P=0.003). MR-HIFU delayed tumor specific growth rates (SGR) from 29 ± 6 to 13 ± 5%/day (P<0.001). Untreated animals (316.5 ± 78.9 mm(3)) had a greater accumulation of (99m)Tc-MDP than HIFU-treated animals (127.0 ± 42.7 mm(3), P=0.004). The total bone volume increase for untreated and HIFU-treated animals was 15.6 ± 9.6% and 3.0 ± 4.1% (P=0.004), respectively. Histological analysis showed ablation of nerve fibers, tumor, inflammatory and bone cells. CONCLUSIONS: Our study provides a detailed characterization of the effects of MR-HIFU treatment on bone metastases, and provides fundamental data, which may motivate and advance its use in the clinical treatment of painful bone metastases with MR-HIFU.

The motility-proliferation-metabolism interplay during metastatic invasion.

Metastasis is the major cause for cancer patients' death, and despite all the recent advances in cancer research it is still mostly incurable. Understanding the mechanisms that are involved in the migration of the cells in a complex environment is a key step towards successful anti-metastatic treatment. Using experimental data-based modeling, we focus on the fundamentals of metastatic invasion: motility, invasion, proliferation and metabolism, and study how they may be combined to maximize the cancer's ability to metastasize. The modeled cells' performance is measured by the number of cells that succeed in migration in a maze, which mimics the extracellular environment. We show that co-existence of different cell clones in the tumor, as often found in experiments, optimizes the invasive ability in a frequently-changing environment. We study the role of metabolism and stimulation by growth factors, and show that metabolism plays a crucial role in the metastatic process and should therefore be targeted for successful treatment.