Enhancement of paclitaxel and carboplatin therapies by CCL2 blockade in ovarian cancers

Chemokine systems in oncology: From microenvironment modulation to nanocarrier innovations

Over the past few decades, significant strides have been made in understanding the pivotal roles that chemokine networks play in tumor biology. These networks, comprising chemokines and their receptors, wield substantial influence over cancer immune regulation and therapeutic outcomes. As a result, targeting these chemokine systems has emerged as a promising avenue for cancer immunotherapy. However, therapies targeting chemokines face significant challenges in solid tumor treatment, due to the complex and fragile of the chemokine networks. A nuanced comprehension of the complicacy and functions of chemokine networks, and their impact on the tumor microenvironment, is essential for optimizing their therapeutic utility in oncology. This review elucidates the ways in which chemokine networks interact with cancer immunity and tumorigenesis. We particularly elaborate on recent innovations in manipulating these networks for cancer treatment. The review also highlights future challenges and explores potential biomaterial strategies for clinical applications.

Key role of exosomes derived from M2 macrophages in maintaining cancer cell stemness (Review)

Cancer stem cells (CSCs) constitute a specific subset of cells found within tumors that are responsible for initiating, advancing and resisting traditional cancer treatments. M2 macrophages, also known as alternatively activated macrophages, contribute to the development and progression of cancer through their involvement in promoting angiogenesis, suppressing the immune system, supporting tumor growth and facilitating metastasis. Exosomes, tiny vesicles released by cells, play a crucial role in intercellular communications and have been shown to be associated with cancer development and progression by influencing the immune response; thus, they may serve as markers for diagnosis and prognosis. Currently, investigating the impact of exosomes derived from M2 macrophages on the maintenance of CSCs is a crucial area of research with the aim of developing novel therapeutic strategies to target this process and improve outcomes for individuals with cancer. Understanding the biological functions of exosomes derived from M2 macrophages and their involvement in cancer may lead to the formulation of novel diagnostic tools and treatments for this disease. By targeting M2 macrophages and the exosomes they secrete, promising prospects emerge for cancer treatment, given their substantial contribution to cancer development and progression. Further research is required to fully grasp the intricate interactions between CSCs, M2 macrophages and exosomes in cancer, and to identify fresh targets for cancer therapy. The present review explores the pivotal roles played by exosomes derived from M2 cells in maintaining the stem‑like properties of cancer cells.

MiRNA-mRNA integrative analysis reveals epigenetically regulated and prognostic miR-103a with a role in migration and invasion of carboplatin-resistant ovarian cancer cells that acquired mesenchymal-like phenotype

BACKGROUND

DNA methylation, histone modifications, and miRNAs affect ovarian cancer (OC) progression and therapy response.

PURPOSE

Identification of epigenetically downregulated miRNAs in drug-resistant OC cell lines with a possible role in drug resistance and/or drug-induced mesenchymal-like phenotype.

METHODS

MiRNA profiling was performed on parental and carboplatin-resistant OC cells, MES-OV and MES-OV CBP. RT-qPCR validation, epigenetic modulation and other CBP-resistant OC cell lines were used to select miRNAs of interest. The integration of miRNA-predicted target genes and differentially expressed genes (DEGs), pathway and functional analysis were used for forecasting their biological role. Data mining was performed to determine their possible prognostic and predictive values.

RESULTS

MiRNA profiling revealed 48 downregulated miRNAs in OC cells whose drug sensitivity and metastatic potential were impacted by epigenetic modulators. Of the fourteen selected, nine were validated as changed, and seven of these restored their expression upon treatment with epigenetic inhibitors. Only three had similar expression patterns in other OC cell lines. MiRNA-mRNA integrative analysis resulted in 56 target DEGs. Pathway analysis revealed that these genes are involved in cell adhesion, migration, and invasion. The functional analysis confirmed the role of miR-103a-3p, miR-17-5p and miR-107 in cell invasion, while data mining showed their prognostic and predictive values. Only miR-103a-3p was epigenetically regulated at the constitutive level.

CONCLUSION

High throughput miRNA and cDNA profiling coupled with pathway analysis and data mining delivered evidence for miRNAs which can be epigenetically regulated in drug-resistant, mesenchymal-like OC cells as possible markers to combat therapy-induced short overall survival and tumor metastatic potential.

Carboplatin-induced upregulation of pan β-tubulin and class III β-tubulin is implicated in acquired resistance and cross-resistance of ovarian cancer

Resistance to platinum- and taxane-based chemotherapy represents a major obstacle to long-term survival in ovarian cancer (OC) patients. Here, we studied the interplay between acquired carboplatin (CBP) resistance using two OC cell models, MES-OV CBP and SK-OV-3 CBP, and non-P-glycoprotein-mediated cross-resistance to paclitaxel (TAX) observed only in MES-OV CBP cells. Decreased platination, mesenchymal-like phenotype, and increased expression of α- and γ-tubulin were observed in both drug-resistant variants compared with parental cells. Both variants revealed increased protein expression of class III β-tubulin (TUBB3) but differences in TUBB3 branching and nuclear morphology. Transient silencing of TUBB3 sensitized MES-OV CBP cells to TAX, and surprisingly also to CBP. This phenomenon was not observed in the SK-OV-3 CBP variant, probably due to the compensation by other β-tubulin isotypes. Reduced TUBB3 levels in MES-OV CBP cells affected DNA repair protein trafficking and increased whole-cell platination level. Furthermore, TUBB3 depletion augmented therapeutic efficiency in additional OC cells, showing vice versa drug-resistant pattern, lacking β-tubulin isotype compensation visible at the level of total β-tubulin (TUBB) in vitro and ex vivo. In summary, the level of TUBB in OC should be considered together with TUBB3 in therapy response prediction.

Chemotherapy-induced metastasis: molecular mechanisms and clinical therapies

Chemotherapy, the most widely accepted treatment for malignant tumors, is dependent on cell death induced by various drugs including antimetabolites, alkylating agents, mitotic spindle inhibitors, antitumor antibiotics, and hormonal anticancer drugs. In addition to causing side effects due to non-selective cytotoxicity, chemotherapeutic drugs can initiate and promote metastasis, which greatly reduces their clinical efficacy. The knowledge of how they induce metastasis is essential for developing strategies that improve the outcomes of chemotherapy. Herein, we summarize the recent findings on chemotherapy-induced metastasis and discuss the underlying mechanisms including tumor-initiating cell expansion, the epithelial-mesenchymal transition, extracellular vesicle involvement, and tumor microenvironment alterations. In addition, the use of combination treatments to overcome chemotherapy-induced metastasis is also elaborated.

Tumor Immune Microenvironment in Gynecologic Cancers

Gynecologic cancers have varying response rates to immunotherapy due to the heterogeneity of each cancer's molecular biology and features of the tumor immune microenvironment (TIME). This article reviews key features of the TIME and its role in the pathophysiology and treatment of ovarian, endometrial, cervical, vulvar, and vaginal cancer. Knowledge of the role of the TIME in gynecologic cancers has been rapidly developing with a large body of preclinical studies demonstrating an intricate yet dichotomous role that the immune system plays in either supporting the growth of cancer or opposing it and facilitating effective treatment. Many targets and therapeutics have been identified including cytokines, antibodies, small molecules, vaccines, adoptive cell therapy, and bacterial-based therapies but most efforts in gynecologic cancers to utilize them have not been effective. However, with the development of immune checkpoint inhibitors, we have started to see the rapid and successful employment of therapeutics in cervical and endometrial cancer. There remain many challenges in utilizing the TIME, particularly in ovarian cancer, and further studies are needed to identify and validate efficacious therapeutics.

Interleukin-33: Friend or Foe in Gastrointestinal Tract Cancers?

Accumulating evidence suggests that Interleukin-33 (IL-33), a member of the IL-1 family, has crucial roles in tissue homeostasis and repair, type 2 immunity, inflammation, and viral infection. IL-33 is a novel contributing factor in tumorigenesis and plays a critical role in regulating angiogenesis and cancer progression in a variety of human cancers. The partially unraveled role of IL-33/ST2 signaling in gastrointestinal tract cancers is being investigated through the analysis of patients' samples and by studies in murine and rat models. In this review, we discuss the basic biology and mechanisms of release of the IL-33 protein and its involvement in gastrointestinal cancer onset and progression.

The role of metabolic reprogramming of tumor-associated macrophages in shaping the immunosuppressive tumor microenvironment

Macrophages are potent immune effector cells in innate immunity and exert dual-effects in the tumor microenvironment (TME). Tumor-associated macrophages (TAMs) make up a significant portion of TME immune cells. Similar to M1/M2 macrophages, TAMs are also highly plastic, and their functions are regulated by cytokines, chemokines and other factors in the TME. The metabolic changes in TAMs are significantly associated with polarization towards a protumour or antitumour phenotype. The metabolites generated via TAM metabolic reprogramming in turn promote tumor progression and immune tolerance. In this review, we explore the metabolic reprogramming of TAMs in terms of energy, amino acid and fatty acid metabolism and the potential roles of these changes in immune suppression.

Sequential targeting of PARP with carboplatin inhibits primary tumour growth and distant metastasis in triple-negative breast cancer

BACKGROUND

Patients with triple-negative breast cancer (TNBC) develop early recurrence. While PARP inhibitors (PARPi) have demonstrated potential in BRCA1/2-mutant (BRCA^MUT) TNBC, durable responses will likely be achieved if PARPi are used in combination. It is plausible that sequential administration of a potent PARPi like talazoparib in combination with carboplatin can enhance primary tumour and metastasis inhibition in BRCA^MUT and BRCA1/2 wild-type (BRCA^WT) TNBCs, and decrease toxicity.

METHODS

We evaluated the impact of the concurrent combination of talazoparib and carboplatin on cell survival in 13 TNBC cell lines. We compared the concurrent and sequential combination upon fork replication, migration and invasion. We also used three orthotopic xenograft models to evaluate primary tumour growth, distant metastasis, and toxicity.

RESULTS

Concurrent talazoparib and carboplatin was synergistic in 92.3% of TNBC cell lines, independent of BRCA1/2-mutation status. The sequential combination decreased fork speed in normal cells, but not in TNBC cells. The talazoparib-first sequential combination resulted in a strong reduction in migration (70.4%, P < 0.0001), invasion (56.9%, P < 0.0001), lung micrometastasis (56.4%, P < 0.0001), and less toxicity in a BRCA^WT model.

CONCLUSION

The sequential combination of talazoparib and carboplatin is an effective approach to inhibit micrometastatic disease, providing rationale for the use of this combination in early TNBC patients.

Transcriptome analysis of newly established carboplatin-resistant ovarian cancer cell model reveals genes shared by drug resistance and drug-induced EMT

BACKGROUND

In ovarian cancer (OC) therapy, even initially responsive patients develop drug resistance.

METHODS

Here, we present an OC cell model composed of variants with differing degrees of acquired resistance to carboplatin (CBP), cross-resistance to paclitaxel, and CBP-induced metastatic properties (migration and invasion). Transcriptome data were analysed by two approaches identifying differentially expressed genes and CBP sensitivity-correlating genes. The impact of selected genes and signalling pathways on drug resistance and metastatic potential, along with their clinical relevance, was examined by in vitro and in silico approaches.

RESULTS

TMEM200A and PRKAR1B were recognised as potentially involved in both phenomena, also having high predictive and prognostic values for OC patients. CBP-resistant MES-OV CBP8 cells were more sensitive to PI3K/Akt/mTOR pathway inhibitors Rapamycin, Wortmannin, SB216763, and transcription inhibitor Triptolide compared with parental MES-OV cells. When combined with CBP, Rapamycin decreased the sensitivity of parental cells while Triptolide sensitised drug-resistant cells to CBP. Four PI3K/Akt/mTOR inhibitors reduced migration in both cell lines.

CONCLUSIONS

A newly established research model and two distinct transcriptome analysis approaches identified novel candidate genes enrolled in CBP resistance development and/or CBP-induced EMT and implied that one-gene targeting could be a better approach than signalling pathway inhibition for influencing both phenomena.

The portrayal of macrophages as tools and targets: A paradigm shift in cancer management

Macrophages play a major role in maintaining an organism's physiology, such as development, homeostasis, tissue repair, and immunity. These immune cells are known to be involved in tumor progression and modulation. Monocytes can be polarized to two types of macrophages (M1 macrophages and pro-tumor M2 macrophages). Through this article, we aim to emphasize the potential of targeting macrophages in order to improve current strategies for tumor management. Various strategies that target macrophages as a therapeutic target have been discussed along with ongoing clinical trials. We have discussed the role of macrophages in various stages of tumor progression epithelial-to-mesenchymal transition (EMT), invasion, maintaining the stability of circulating tumor cells (CTCs) in blood, and establishing a premetastatic niche along with the role of various cytokines and chemokines involved in these processes. Intriguingly macrophages can also serve as drug carriers due to their tumor tropism along the chemokine gradient. They surpass currently explored nanotherapeutics in tumor accumulation and circulation half-life. We have emphasized on macrophage-based biomimetic formulations and macrophage-hitchhiking as a strategy to effectively target tumors. We firmly believe that targeting macrophages or utilizing them as an indigenous carrier system could transform cancer management.

Targeting tumor-associated macrophages for successful immunotherapy of ovarian carcinoma

Epithelial ovarian cancer (EOC) is among the top five causes of cancer-related death in women, largely reflecting early, prediagnosis dissemination of malignant cells to the peritoneum. Despite improvements in medical therapies, particularly with the implementation of novel drugs targeting homologous recombination deficiency, the survival rates of patients with EOC remain low. Unlike other neoplasms, EOC remains relatively insensitive to immune checkpoint inhibitors, which is correlated with a tumor microenvironment (TME) characterized by poor infiltration by immune cells and active immunosuppression dominated by immune components with tumor-promoting properties, especially tumor-associated macrophages (TAMs). In recent years, TAMs have attracted interest as potential therapeutic targets by seeking to reverse the immunosuppression in the TME and enhance the clinical efficacy of immunotherapy. Here, we review the key biological features of TAMs that affect tumor progression and their relevance as potential targets for treating EOC. We especially focus on the therapies that might modulate the recruitment, polarization, survival, and functional properties of TAMs in the TME of EOC that can be harnessed to develop superior combinatorial regimens with immunotherapy for the clinical care of patients with EOC.

Regulatory cells and the effect of cancer immunotherapy

Several mechanisms and cell types are involved in the regulation of the immune response. These include mostly regulatory T cells (Tregs), regulatory macrophages (Mregs), myeloid suppressor cells (MDSCs) and other regulatory cell types such as tolerogenic dendritic cells (tolDCs), regulatory B cells (Bregs), and mesenchymal stem cells (MSCs). These regulatory cells, known for their ability to suppress immune responses, can also suppress the anti-tumor immune response. The infiltration of many regulatory cells into tumor tissues is therefore associated with a poor prognosis. There is growing evidence that elimination of Tregs enhances anti-tumor immune responses. However, the systemic depletion of Treg cells can simultaneously cause deleterious autoimmunity. Furthermore, since regulatory cells are characterized by their high level of expression of immune checkpoints, it is also expected that immune checkpoint inhibitors perform part of their function by blocking these molecules and enhancing the immune response. This indicates that immunotherapy does not only act by activating specific effector T cells but can also directly or indirectly attenuate the suppressive activity of regulatory cells in tumor tissues. This review aims to draw together our current knowledge about the effect of immunotherapy on the various types of regulatory cells, and how these effects may be beneficial in the response to immunotherapy.

Tumor-associated macrophage polarization in the inflammatory tumor microenvironment

The chronic inflammation of tumor continues to recruit TAMs (tumor-associated macrophages) to the TME (tumor microenvironment) and promote polarization. Pro-inflammatory signals polarize macrophages to the M1 phenotype to enhance inflammation against pathogens. Tumor inflammatory development changes the pro-inflammatory response to an anti-inflammatory response, resulting in the alteration of macrophages from M1 to M2 to promote tumor progression. Additionally, hypoxia activates HIF (hypoxia-inducible factors) in the TME, which reprograms macrophages to the M2 phenotype to support tumor development. Here, we discuss the factors that drive phenotypic changes in TAMs in the inflammatory TME, which will help in the development of cancer immunotherapy of macrophages.

Therapeutic implications of the tumor microenvironment in ovarian cancer patients receiving PD-1/PD-L1 therapy

Epithelial ovarian cancer (EOC) ranks as the second most common cause of gynecologic cancer death. The conventional treatment for patients with EOC is postoperative therapy along with platinum chemotherapy. However, a more efficient treatment regimen is of great need for these patients diagnosed with advanced disease (FIGO stages III–IV), whose survival is approximately 29%. Immunotherapy seems to be an encouraging therapeutic strategy for EOC. Given the crucial role in the complicated interactions between tumor cells and other cells, the tumor microenvironment (TME) influences the response to immunotherapy. In this review, we discuss feasible strategies for EOC immunotherapy by exploiting the reciprocity of cancer cells and the constituents of the TME.

CC Chemokine Ligand-2: A Promising Target for Overcoming Anticancer Drug Resistance

Simple Summary

Drug resistance is an obstacle to cancer therapy, and the underlying mechanisms are still being explored. CC chemokine ligand-2 (CCL2) is one of the key proinflammatory chemokines that regulate the migration and infiltration of multiple inflammatory cells, such as monocytes and macrophages. CCL2 can be secreted by tumor cells and multiple cell types, mediating the formation of the tumor-promoting and immunosuppressive microenvironment to promote cancer development, progression, and anticancer drug resistance. Notably, CCL2 is also frequently overexpressed in drug-resistant cancer cells. Here, we review recent findings regarding the role of CCL2 in the development of resistance to multiple anticancer reagents. In addition, the possible mechanisms by which CCL2 participates in anticancer drug resistance are discussed, which may provide new therapeutic targets for reversing cancer resistance.

Abstract

CC chemokine ligand-2 (CCL2), a proinflammatory chemokine that mediates chemotaxis of multiple immune cells, plays a crucial role in the tumor microenvironment (TME) and promotes tumorigenesis and development. Recently, accumulating evidence has indicated that CCL2 contributes to the development of drug resistance to a broad spectrum of anticancer agents, including chemotherapy, hormone therapy, targeted therapy, and immunotherapy. It has been reported that CCL2 can reduce tumor sensitivity to drugs by inhibiting drug-induced apoptosis, antiangiogenesis, and antitumor immunity. In this review, we mainly focus on elucidating the relationship between CCL2 and resistance as well as the underlying mechanisms. A comprehensive understanding of the role and mechanism of CCL2 in anticancer drug resistance may provide new therapeutic targets for reversing cancer resistance.

Asparagus officinalis combined with paclitaxel exhibited synergistic anti-tumor activity in paclitaxel-sensitive and -resistant ovarian cancer cells

PURPOSE

Although paclitaxel is a promising first-line chemotherapeutic drug for ovarian cancer, acquired resistance to paclitaxel is one of the leading causes of treatment failure, limiting its clinical application. Asparagus officinalis has been shown to have anti-tumorigenic effects on cell growth, apoptosis, cellular stress and invasion of various types of cancer cells and has also been shown to synergize with paclitaxel to inhibit cell proliferation in ovarian cancer.

METHODS

Human ovarian cancer cell lines MES and its PTX-resistant counterpart MES-TP cell lines were used and were treated with Asparagus officinalis and paclitaxel alone as well as in combination. Cell proliferation, cellular stress, invasion and DMA damage were investigated and the synergistic effect of a combined therapy analyzed.

RESULTS

In this study, we found that Asparagus officinalis combined with low-dose paclitaxel synergistically inhibited cell proliferation, induced cellular stress and apoptosis and reduced cell invasion in paclitaxel-sensitive and -resistant ovarian cancer cell lines. The combined treatment effects were dependent on DNA damage pathways and suppressing microtubule dynamics, and the AKT/mTOR pathway and microtubule-associated proteins regulated the inhibitory effect through different mechanisms in paclitaxel-sensitive and -resistant cells.

CONCLUSION

These findings suggest that the combination of Asparagus officinalis and paclitaxel have potential clinical implications for development as a novel ovarian cancer treatment strategy.

DDR2 Expression in Cancer-Associated Fibroblasts Promotes Ovarian Cancer Tumor Invasion and Metastasis through Periostin-ITGB1

Ovarian cancer has the highest mortality of all gynecologic malignancies. As such, there is a need to identify molecular mechanisms that underlie tumor metastasis in ovarian cancer. Increased expression of receptor tyrosine kinase, DDR2, has been associated with worse patient survival. Identifying downstream targets of DDR2 may allow specific modulation of ovarian cancer metastatic pathways. Additionally, stromal cells play a critical role in metastasis. The crosstalk between tumor and stromal cells can lead to tumor progression. We first identified that tumor cells co-cultured with DDR2-expressing fibroblasts had lower periostin expression when compared to tumor cells co-cultured with DDR2-depleted fibroblasts. We confirmed that DDR2 regulates POSTN expression in ovarian cancer-associated fibroblasts (CAFs). We found that mesothelial cell clearance and invasion by tumor cells were enhanced three-fold when DDR2 and POSTN-expressing CAFs were present compared to DDR2 and POSTN-depleted CAFs. Furthermore, DDR2-depleted and POSTN-overexpressing CAFs co-injected with ovarian tumor cells had increased tumor burden compared to mice injected with tumor cells and DDR2 and POSTN-depleted CAFs. Furthermore, we demonstrated that DDR2 regulates periostin expression through integrin B1 (ITGB1). Stromal DDR2 is highly correlated with stromal POSTN expression in ovarian cancer patient tumors. Thus, DDR2 expression in CAFs regulates the steps of ovarian cancer metastasis through periostin.

Leveraging macrophages for cancer theranostics

As fundamental immune cells in innate and adaptive immunity, macrophages engage in a double-edged relationship with cancer. Dissecting the character of macrophages in cancer development facilitates the emergence of macrophages-based new strategies that encompass macrophages as theranostic targets/tools of interest for treating cancer. Herein, we provide a concise overview of the mixed roles of macrophages in cancer pathogenesis and invasion as a foundation for the review discussions. We survey the latest progress on macrophage-based cancer theranostic strategies, emphasizing two major strategies, including targeting the endogenous tumor-associated macrophages (TAMs) and engineering the adoptive macrophages to reverse the immunosuppressive environment and augment the cancer theranostic efficacy. We also discuss and provide insights on the major challenges along with exciting opportunities for the future of macrophage-based cancer theranostic approaches.

Molecular imaging of tumor-associated macrophages in cancer immunotherapy

Tumor-associated macrophages (TAMs), the most abundant inflammatory cell group in the tumor microenvironment, play an essential role in tumor immune regulation. The infiltration degree of TAMs in the tumor microenvironment is closely related to tumor growth and metastasis, and TAMs have become a promising target in tumor immunotherapy. Molecular imaging is a new interdisciplinary subject that combines medical imaging technology with molecular biology, nuclear medicine, radiation medicine, and computer science. The latest progress in molecular imaging allows the biological processes of cells to be visualized in vivo, which makes it possible to better understand the density and distribution of macrophages in the tumor microenvironment. This review mainly discusses the application of targeting TAM in tumor immunotherapy and the imaging characteristics and progress of targeting TAM molecular probes using various imaging techniques.

Down-regulation of ZNF252P-AS1 alleviates ovarian cancer progression by binding miR-324-3p to downregulate LY6K

Background

Ovarian cancer is a common gynecological malignant disease in women. Our work aimed to study the specific functions of ZNF252P antisense RNA 1 (ZNF252P-AS1) in ovarian cancer.

Methods

ZNF252P-AS1, miR-324-3p, and lymphocyte antigen 6 family member K (LY6K) expression were analyzed by bioinformatics tools in ovarian cancer tissues and was quantified by qRT-PCR in ovarian cancer cells. The effect of ZNF252P-AS1 knockdown, miR-324-3p suppression, and LY6K over-expression on apoptosis, cell viability, invasion, migration, and epithelial to mesenchymal transition (EMT) was determined in vitro by using colony formation and EdU assays, flow cytometry, transwell assay, and Western blot. The interactions between ZNF252P-AS1 and miR-324-3p and between miR-324-3p and LY6K were validated by luciferase assays. The effects of restraining ZNF252P-AS1 in vivo were studied using BALB/c male nude mice.

Results

ZNF252P-AS1 and LY6K levels were up-regulated, while miR-324-3p was declined in ovarian cancer tissues and cells. ZNF252P-AS1 knockdown reduced ovarian cancer cell proliferation, invasion, migration, and EMT, whereas promoted its apoptosis. Besides, ZNF252P-AS1 interacted with miR-324-3p and reversely regulated its level, and miR-324-3p was directly bound to LY6K and negatively regulated its expression. Moreover, ZNF252P-AS1 knockdown reversed the effect of miR-324-3p on cancer cell apoptosis, growth, migration, invasion, and EMT. Similar results were discovered in the rescue experiments between miR-324-3p and LY6K. Additionally, mouse models in vivo experiments further validated that ZNF252P-AS1 knockdown distinctly inhibited tumor growth.

Conclusion

ZNF252P-AS1 mediated miR-324-3p/LY6K signaling to facilitate progression of ovarian cancer.

Macrophages in ovarian cancer and their interactions with monoclonal antibody therapies

The unmet clinical need for effective treatments in ovarian cancer has yet to be addressed using monoclonal antibodies (mAbs), which have largely failed to overcome tumour-associated immunosuppression, restrict cancer growth, and significantly improve survival. In recent years, experimental mAb design has moved away from solely targeting ovarian tumours and instead sought to modulate the wider tumour microenvironment (TME). Tumour-associated macrophages (TAMs) may represent an attractive therapeutic target for mAbs in ovarian cancer due to their high abundance and close proximity to tumour cells and their active involvement in facilitating several pro-tumoural processes. Moreover, the expression of several antibody crystallisable fragment (Fc) receptors and broad phenotypic plasticity of TAMs provide opportunities to modulate TAM polarisation using mAbs to promote anti-tumoural phenotypes. In this review, we discuss the role of TAMs in ovarian cancer TME and the emerging strategies to target the contributions of these cells in tumour progression through the rationale design of mAbs.

GAS6/AXL Inhibition Enhances Ovarian Cancer Sensitivity to Chemotherapy and PARP Inhibition through Increased DNA Damage and Enhanced Replication Stress

Over 80% of women with high-grade serous ovarian cancer (HGSOC) develop tumor resistance to chemotherapy and die of their disease. There are currently no FDA-approved agents to improve sensitivity to first-line platinum- and taxane-based chemotherapy or to PARP inhibitors. Here, we tested the hypothesis that expression of growth arrest-specific 6 (GAS6), the ligand of receptor tyrosine kinase AXL, is associated with chemotherapy response and that sequestration of GAS6 with AVB-S6-500 (AVB-500) could improve tumor response to chemotherapy and PARP inhibitors. We found that GAS6 levels in patient tumor and serum samples collected before chemotherapy correlated with ovarian cancer chemoresponse and patient survival. Compared with chemotherapy alone, AVB-500 plus carboplatin and/or paclitaxel led to decreased ovarian cancer-cell survival in vitro and tumor burden in vivo. Cells treated with AVB-500 plus carboplatin had more DNA damage, slower DNA replication fork progression, and fewer RAD51 foci than cells treated with carboplatin alone, indicating AVB-500 impaired homologous recombination (HR). Finally, treatment with the PARP inhibitor olaparib plus AVB-500 led to decreased ovarian cancer-cell survival in vitro and less tumor burden in vivo. Importantly, this effect was seen in HR-proficient and HR-deficient ovarian cancer cells. Collectively, our findings suggest that GAS6 levels could be used to predict response to carboplatin and AVB-500 could be used to treat platinum-resistant, HR-proficient HGSOC. IMPLICATIONS: GAS6/AXL is a novel target to sensitize ovarian cancers to carboplatin and olaparib. Additionally, GAS6 levels can be associated with response to carboplatin treatment.

Role of the CCL2-CCR2 signalling axis in cancer: Mechanisms and therapeutic targeting

The chemokine ligand CCL2 and its receptor CCR2 are implicated in the initiation and progression of various cancers. CCL2 can activate tumour cell growth and proliferation through a variety of mechanisms. By interacting with CCR2, CCL2 promotes cancer cell migration and recruits immunosuppressive cells to the tumour microenvironment, favouring cancer development. Over the last several decades, a series of studies have been conducted to explore the CCL2-CCR2 signalling axis function in malignancies. Therapeutic strategies targeting the CCL2- CCR2 axis have also shown promising effects, enriching our approaches for fighting against cancer. In this review, we summarize the role of the CCL2-CCR2 signalling axis in tumorigenesis and highlight recent studies on CCL2-CCR2 targeted therapy, focusing on preclinical studies and clinical trials.

An Overview of Ovarian Cancer: Molecular Processes Involved and Development of Target-based Chemotherapeutics

Ovarian cancer is one of the leading gynecologic diseases with a high mortality rate worldwide. Current statistical studies on cancer reveal that over the past two decades, the fifth most common cause of death related to cancer in females of the western world is ovarian cancer. In spite of significant strides made in genomics, proteomics and radiomics, there has been little progress in transitioning these research advances into effective clinical administration of ovarian cancer. Consequently, researchers have diverted their attention to finding various molecular processes involved in the development of this cancer and how these processes can be exploited to develop potential chemotherapeutics to treat this cancer. The present review gives an overview of these studies which may update the researchers on where we stand and where to go further. The unfortunate situation with ovarian cancer that still exists is that most patients with it do not show any symptoms until the disease has moved to an advanced stage. Undoubtedly, several targets-based drugs have been developed to treat it, but drug-resistance and the recurrence of this disease are still a problem. For the development of potential chemotherapeutics for ovarian cancer, however, some theoretical approaches have also been applied. A description of such methods and their success in this direction is also covered in this review.

Kaempferia parviflora extract inhibits TNF-α-induced release of MCP-1 in ovarian cancer cells through the suppression of NF-κB signaling

Ovarian clear cell carcinoma (OCCC) is an uncommon subtype of epithelial cell ovarian cancers (EOCs) that has poor response to conventional platinum-based therapy. Therefore, finding new potential therapeutic agents is required. Since inflammatory cytokine, tumor necrosis factor alpha (TNF-α), is strongly expressed in EOCs and associated with the level of tumor grade, disruption of this inflammation pathway may provide another potential target for OCCC treatment. We previously reported that Kaempferia parviflora (KP) extract decreased cell proliferation and induced apoptosis. However, the effects of KP on OCCC, especially the aspects related to inflammatory cytokines, have not been elucidated. Our current study demonstrated the effects of KP extract on cytokine production in TNF-α-induced OCCC TOV-21G cell line. This study showed that KP extract inhibited interleukin 6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1) production at both transcription and translation levels via the suppression of nuclear factor-kappa B (NF-κB) signal transduction. In contrast, KP extract increased the expression of inhibitor kappa B (IκB) protein which may delay NF-κB translocation into the nucleus upon TNF-α activation. Moreover, the suppression of cytokines released from KP treated-TOV-21G reduced the migration of monocyte cell (THP-1). KP extract also exhibited the inhibition of IL-6 and MCP-1 production from THP-1 activated by lipopolysaccharides (LPS). Cells treated with KP extract exhibited a decrease in extracellular signal-regulated kinases (ERK1/2) and protein kinase B (AKT) phosphorylation and induced myeloid leukemia cell differentiation protein Mcl-1 (MCL-1) expression. Suppression of inflammatory cytokine and chemokine production and inhibition of tumor-associated macrophage (TAM) migration support the possibility of using KP for OCCC treatment.

Tumor-Associated Macrophages: Combination of Therapies, the Approach to Improve Cancer Treatment

Macrophages are one of the most important cells of the innate immune system and are known for their ability to engulf and digest foreign substances, including cellular debris and tumor cells. They can convert into tumor-associated macrophages (TAMs) when mature macrophages are recruited into the tumor microenvironment. Their role in cancer progression, metastasis, and therapy failure is of special note. The aim of this review is to understand how the presence of TAMs are both advantageous and disadvantageous in the immune system.

New insight towards development of paclitaxel and docetaxel resistance in cancer cells: EMT as a novel molecular mechanism and therapeutic possibilities

Epithelial-to-mesenchymal transition (EMT) mechanism is responsible for metastasis and migration of cancer cells to neighboring cells and tissues. Morphologically, epithelial cells are transformed to mesenchymal cells, and at molecular level, E-cadherin undergoes down-regulation, while an increase occurs in N-cadherin and vimentin levels. Increasing evidence demonstrates role of EMT in mediating drug resistance of cancer cells. On the other hand, paclitaxel (PTX) and docetaxel (DTX) are two chemotherapeutic agents belonging to taxene family, capable of inducing cell cycle arrest in cancer cells via preventing microtubule depolymerization. Aggressive behavior of cancer cells resulted from EMT-mediated metastasis can lead to PTX and DTX resistance. Upstream mediators of EMT such as ZEB1/2, TGF-β, microRNAs, and so on are involved in regulating response of cancer cells to PTX and DTX. Tumor-suppressing factors inhibit EMT to promote PTX and DTX sensitivity of cancer cells. Furthermore, three different strategies including using anti-tumor compounds, gene therapy and delivery systems have been developed for suppressing EMT, and enhancing cytotoxicity of PTX and DTX against cancer cells that are mechanistically discussed in the current review.

Prognostic significance and targeting tumor-associated macrophages in cancer: new insights and future perspectives

Macrophages are phagocytic sentinel cells of the immune system that are central to both innate and adaptive immune responses and serve as the first line of defense against pathogenic insults to tissues. In the tumor microenvironment, tumor-derived factors induce monocyte polarization towards a pro-tumor phenotype. The pro-tumor macrophages regulate key steps in tumorigenicity including tumor growth, angiogenesis, immune suppression, and metastasis. Macrophage infiltration in solid tumors correlates with poor prognosis and resistance to chemotherapy in most cancers. Here in this review, we will shed light on tumor-associated macrophages (TAMs) in regulating tumorigenicity and TAMs as a prognostic biomarker. Also, we will review the recent advances in targeting TAMs to increase the prognosis of cancer patients.

Genome-wide CRISPR/Cas9 knockout screening uncovers a novel inflammatory pathway critical for resistance to arginine-deprivation therapy

Arginine synthesis deficiency due to the suppressed expression of ASS1 (argininosuccinate synthetase 1) represents one of the most frequently occurring metabolic defects of tumor cells. Arginine-deprivation therapy has gained increasing attention in recent years. One challenge of ADI-PEG20 (pegylated ADI) therapy is the development of drug resistance caused by restoration of ASS1 expression and other factors. The goal of this work is to identify novel factors conferring therapy resistance.

Methods: Multiple, independently derived ADI-resistant clones including derivatives of breast (MDA-MB-231 and BT-549) and prostate (PC3, CWR22Rv1, and DU145) cancer cells were developed. RNA-seq and RT-PCR were used to identify genes upregulated in the resistant clones. Unbiased genome-wide CRISPR/Cas9 knockout screening was used to identify genes whose absence confers sensitivity to these cells. shRNA and CRISPR/Cas9 knockout as well as overexpression approaches were used to validate the functions of the resistant genes both in vitro and in xenograft models. The signal pathways were verified by western blotting and cytokine release.

Results: Based on unbiased CRISPR/Cas9 knockout screening and RNA-seq analyses of independently derived ADI-resistant (ADIR) clones, aberrant activation of the TREM1/CCL2 axis in addition to ASS1 expression was consistently identified as the resistant factors. Unlike ADIR, MDA-MB-231 overexpressing ASS1 cells achieved only moderate ADI resistance both in vitro and in vivo, and overexpression of ASS1 alone does not activate the TREM1/CCL2 axis. These data suggested that upregulation of TREM1 is an independent factor in the development of strong resistance, which is accompanied by activation of the AKT/mTOR/STAT3/CCL2 pathway and contributes to cell survival and overcoming the tumor suppressive effects of ASS1 overexpression. Importantly, knockdown of TREM1 or CCL2 significantly sensitized ADIR toward ADI. Similar results were obtained in BT-549 breast cancer cell line as well as castration-resistant prostate cancer cells. The present study sheds light on the detailed mechanisms of resistance to arginine-deprivation therapy and uncovers novel targets to overcome resistance.

Conclusion: We uncovered TREM1/CCL2 activation, in addition to restored ASS1 expression, as a key pathway involved in full ADI-resistance in breast and prostate cancer models.

Is the C-C Motif Ligand 2-C-C Chemokine Receptor 2 Axis a Promising Target for Cancer Therapy and Diagnosis?

C-C motif ligand 2 (CCL2) was originally reported as a chemical mediator attracting mononuclear cells to inflammatory tissue. Many studies have reported that CCL2 can directly activate cancer cells through a variety of mechanisms. CCL2 can also promote cancer progression indirectly through increasing the recruitment of tumor-associated macrophages into the tumor microenvironment. The role of CCL2 in cancer progression has gradually been understood, and various preclinical cancer models elucidate that CCL2 and its receptor C-C chemokine receptor 2 (CCR2) are attractive targets for intervention in cancer development. However, clinically available drugs that regulate the CCL2-CCR2 axis as anticancer agents are not available at this time. The complete elucidation of not only the oncological but also the physiological functions of the CCL2-CCR2 axis is required for achieving a satisfactory effect of the CCL2-CCR2 axis-targeted therapy.

Targeting tumor-associated macrophages: A potential treatment for solid tumors

Tumor-associated macrophages (TAMs) in solid tumors exert protumor activities by releasing cytokines or growth factors into the tumor microenvironment. Increasing studies have also shown that TAMs play a key role in tumor progression, such as tumor angiogenesis, immunosuppression, cell proliferation, migration, invasion, and metastasis. A large body of evidence shows that the abundance of TAMs in solid tumors is correlated with poor disease prognosis and resistance to therapies. Therefore, targeting TAMs in solid tumors is considered to be a promising immunotherapeutic strategy. At present, the therapeutic strategies of targeting macrophages mainly include limiting monocyte recruitment, depletion strategies, promoting macrophage phagocytic activity, and induction of macrophage reprogramming. Additionally, targeting TAMs in combination with conventional therapies has been demonstrated to be a promising therapeutic strategy in solid tumors. In the present review, we summarized various TAMs-targeting therapeutic strategies for treating solid tumors. This review also discusses the challenges for targeting TAMs as tumor treatments, the obstacles in clinical trials, and the perspective for the future development of TAMs-targeting therapies for various cancers.

CC Chemokines in a Tumor: A Review of Pro-Cancer and Anti-Cancer Properties of the Ligands of Receptors CCR1, CCR2, CCR3, and CCR4

CC chemokines, a subfamily of 27 chemotactic cytokines, are a component of intercellular communication, which is crucial for the functioning of the tumor microenvironment. Although many individual chemokines have been well researched, there has been no comprehensive review presenting the role of all known human CC chemokines in the hallmarks of cancer, and this paper aims at filling this gap. The first part of this review discusses the importance of CCL1, CCL3, CCL4, CCL5, CCL18, CCL19, CCL20, CCL21, CCL25, CCL27, and CCL28 in cancer. Here, we discuss the significance of CCL2 (MCP-1), CCL7, CCL8, CCL11, CCL13, CCL14, CCL15, CCL16, CCL17, CCL22, CCL23, CCL24, and CCL26. The presentation of each chemokine includes its physiological function and then the role in tumor, including proliferation, drug resistance, migration, invasion, and organ-specific metastasis of tumor cells, as well as the effects on angiogenesis and lymphangiogenesis. We also discuss the effects of each CC chemokine on the recruitment of cancer-associated cells to the tumor niche (eosinophils, myeloid-derived suppressor cells (MDSC), tumor-associated macrophages (TAM), tumor-associated neutrophils (TAN), regulatory T cells (T_reg)). On the other hand, we also present the anti-cancer properties of CC chemokines, consisting in the recruitment of tumor-infiltrating lymphocytes (TIL).

Tumor-associated macrophages: A promising target for a cancer immunotherapeutic strategy

Macrophages, a type of myeloid immune cell, play essential roles in fighting against pathogenic invasion and activating T cell-mediated adaptive immune responses. As a major constituent of the tumor microenvironment (TME), macrophages play a complex role in tumorigenesis and tumor progression. They can inhibit tumor growth by releasing proinflammatory cytokines and exerting cytotoxic activities but principally contribute to tumor progression by promoting tumor proliferation, angiogenesis, and metastasis. The tumor-promoting hallmarks of macrophages have aroused widespread interest in targeting tumor-associated macrophages (TAMs) for cancer immunotherapy. Increasing preclinical and clinical studies suggest that TAMs are a promising target for cancer immunotherapy. To date, TAM-targeted therapeutic strategies have mainly been divided into two kinds: inhibiting pro-tumor TAMs and activating anti-tumor TAMs. We reviewed the heterogeneous and plastic characteristics of macrophages in the TME and the feasible strategies to target TAMs in cancer immunotherapy and summarized the complementary effect of TAM-targeted therapy with traditional treatments or other immunotherapies.

The role of caspase-8 in the tumor microenvironment of ovarian cancer

Caspase-8 is an aspartate-specific cysteine protease, which is best known for its apoptotic functions. Caspase-8 is placed at central nodes of multiple signal pathways, regulating not only the cell cycle but also the invasive and metastatic cell behavior, the immune cell homeostasis and cytokine production, which are the two major components of the tumor microenvironment (TME). Ovarian cancer often has dysregulated caspase-8 expression, leading to imbalance between its apoptotic and non-apoptotic functions within the tumor and the surrounding milieu. The downregulation of caspase-8 in ovarian cancer seems to be linked to high aggressiveness with chronic inflammation, immunoediting, and immune resistance. Caspase-8 plays therefore an essential role not only in the primary tumor cells but also in the TME by regulating the immune response, B and T lymphocyte activation, and macrophage differentiation and polarization. The switch between M1 and M2 macrophages is possibly associated with changes in the caspase-8 expression. In this review, we are discussing the non-apoptotic functions of caspase-8, highlighting this protein as a modulator of the immune response and the cytokine composition in the TME. Considering the low survival rate among ovarian cancer patients, it is urgently necessary to develop new therapeutic strategies to optimize the response to the standard treatment. The TME is highly heterogenous and provides a variety of opportunities for new drug targets. Given the variety of roles of caspase-8 in the TME, we should focus on this protein in the development of new therapeutic strategies against the TME of ovarian cancer.

Targeting tumor-associated macrophages for cancer immunotherapy

Macrophages are important effector cells of the innate immune system and are also major components of the tumor microenvironment (TME). Macrophages that are abundant in the TME are called tumor-associated macrophages (TAMs). As TAMs promote strong tumor angiogenesis and support tumor cell survival, they are closely related to tumor growth. Several studies have demonstrated that reducing the density or effects of TAMs can inhibit the growth of tumors, making them targets for cancer immunotherapy, which has become a research hot spot. Several clinical and preclinical trials have studied drugs that inhibit the effects of and reduce the population of phagocytes that target TAMs achieve cancer immunotherapy. In this paper, we summarize the various methods of targeting TAMs for tumor immunotherapy, focusing on TAM mechanisms, sources, and polarization.

Tumor Microenvironment in Ovarian Cancer: Function and Therapeutic Strategy

Ovarian cancer is one of the leading causes of death in patients with gynecological malignancy. Despite optimal cytoreductive surgery and platinum-based chemotherapy, ovarian cancer disseminates and relapses frequently, with poor prognosis. Hence, it is urgent to find new targeted therapies for ovarian cancer. Recently, the tumor microenvironment has been reported to play a vital role in the tumorigenesis of ovarian cancer, especially with discoveries from genome-, transcriptome- and proteome-wide studies; thus tumor microenvironment may present potential therapeutic target for ovarian cancer. Here, we review the interactions between the tumor microenvironment and ovarian cancer and various therapies targeting the tumor environment.

Hypoxia Alters the Expression of CC Chemokines and CC Chemokine Receptors in a Tumor-A Literature Review

Hypoxia, i.e., oxygen deficiency condition, is one of the most important factors promoting the growth of tumors. Since its effect on the chemokine system is crucial in understanding the changes in the recruitment of cells to a tumor niche, in this review we have gathered all the available data about the impact of hypoxia on β chemokines. In the introduction, we present the chronic (continuous, non-interrupted) and cycling (intermittent, transient) hypoxia together with the mechanisms of activation of hypoxia inducible factors (HIF-1 and HIF-2) and NF-κB. Then we describe the effect of hypoxia on the expression of chemokines with the CC motif: CCL1, CCL2, CCL3, CCL4, CCL5, CCL7, CCL8, CCL11, CCL13, CCL15, CCL16, CCL17, CCL18, CCL19, CCL20, CCL21, CCL22, CCL24, CCL25, CCL26, CCL27, CCL28 together with CC chemokine receptors: CCR1, CCR2, CCR3, CCR4, CCR5, CCR6, CCR7, CCR8, CCR9, and CCR10. To better understand the effect of hypoxia on neoplastic processes and changes in the expression of the described proteins, we summarize the available data in a table which shows the effect of individual chemokines on angiogenesis, lymphangiogenesis, and recruitment of eosinophils, myeloid-derived suppressor cells (MDSC), regulatory T cells (T_reg), and tumor-associated macrophages (TAM) to a tumor niche.

Comparison of the therapeutic effects of lobaplatin and carboplatin on retinoblastoma in vitro and in vivo

Retinoblastoma (RB) is one of the most aggressive malignancies affecting infants and children. Platinum drugs are commonly used in the treatment of RB; however, their efficacy is often compromised by drug resistance and severe toxicity. The present study aimed to investigate and compare the toxicity and antitumor activity of the third-generation platinum drugs, carboplatin and lobaplatin, in vitro and in vivo. The Y79 RB cell line was treated with carboplatin or lobaplatin in vitro and then used to establish xenografts in immunodeficient nude mice in vivo; the effects of pharmacological doses of these drugs were then assessed. High concentrations of carboplatin and lobaplatin markedly inhibited Y79 RB cell proliferation in vitro. In addition, the lobaplatin group exhibited higher proportions of early-stage apoptotic cells than the carboplatin group, while no significant differences in the proportions of cells in the S phase were observed between the 2 groups, as shown by flow cytometry. Significant changes in the E2F1/Cdc25a/Cdk2 pathway in the RB cells were detected by RNA-seq following carboplatin or lobaplatin intervention. RT-qPCR, immunofluorescence and immunohistochemical analyses in vivo and in vitro demonstrated that the trends of drug-induced inhibition of tumor pathological changes may have been regulated through the E2F1/Cdc25a/Cdk2 pathway, and that lobaplatin was more effective than carboplatin in controlling tumors in vivo. On the whole, the findings of the present study demonstrate that lobaplatin is associated with lower cytotoxicity and exerts more prominent therapeutic effects than carboplatin on Y79 RB cells in vitro and in mice in vivo.

Targeting Mononuclear Phagocyte Receptors in Cancer Immunotherapy: New Perspectives of the Triggering Receptor Expressed on Myeloid Cells (TREM-1)

Inflammatory cells are major players in the onset of cancer. The degree of inflammation and type of inflammatory cells in the tumor microenvironment (TME) are responsible for tilting the balance between tumor progression and regression. Cancer-related inflammation has also been shown to influence the efficacy of conventional therapy. Mononuclear phagocytes (MPs) represent a major component of the inflammatory circuit that promotes tumor progression. Despite their potential to activate immunosurveillance and exert anti-tumor responses, MPs are subverted by the tumor to support its growth, immune evasion, and spread. MP responses in the TME are dictated by a network of stimuli integrated through the cross-talk between activatory and inhibitory receptors. Alterations in receptor expression/signaling can create excessive inflammation and, when chronic, promote tumorigenesis. Research advances have led to the development of new therapeutic strategies aimed at receptor targeting to induce a tumor-infiltrating MP switch from a cancer-supportive toward an anti-tumor phenotype, demonstrating efficacy in different human cancers. This review provides an overview of the role of MP receptors in inflammation-mediated carcinogenesis and discusses the most recent updates regarding their targeting for immunotherapeutic purposes. We focus in particular on the TREM-1 receptor, a major amplifier of MP inflammatory responses, highlighting its relevance in the development and progression of several types of inflammation-associated malignancies and the promises of its inhibition for cancer immunotherapy.

Role of CC Chemokines Subfamily in the Platinum Drugs Resistance Promotion in Cancer

Cancer is a significant medical issue, being one of the main causes of mortality around the world. The therapies for this pathology depend on the stage in which the cancer is found, but it is usually diagnosed at an advanced stage in which the treatment is chemotherapy. Platinum drugs are among the most commonly used in therapy, unfortunately, one of the main obstacles to this treatment is the development of chemoresistance, which is the ability of cancer cells to evade the effects of drugs. Although some molecular mechanisms involved in resistance to platinum drugs are described, elucidation is still required of others. Secretion of inflammatory mediators such as cytokines and chemokines, by tumor microenvironment components or tumor cells, show direct influence on proliferation, metastasis and progression of cancer and are related to chemoresistance and poor prognosis. In this review, the general mechanisms associated with resistance to platinum drugs, inflammation on cancer development and chemoresistance in various types of cancer will be approached with special emphasis on the current history of CC chemokines subfamily-mediated chemoresistance.

CCL2-CCR2 axis recruits tumor associated macrophages to induce immune evasion through PD-1 signaling in esophageal carcinogenesis

Background

The poor prognosis of esophageal squamous cell carcinoma (ESCC) highlights the need for novel strategies against this disease. Our previous study suggested the involvement of CCL2 and tumor associated macrophages (TAMs) in esophageal carcinogenesis. Despite the recognition of TAMs as a promising target for cancer treatment, mechanisms underlying its infiltration, activation and tumor-promotive function in ESCC remain unknown.

Methods

Human esophageal tissue array and TCGA database were used to evaluate the clinical relevance of CCL2 and TAMs in ESCC. F344 rats and C57BL/6 mice were treated with N-nitrosomethylbenzylamine (NMBA) to establish orthotopic models of esophageal carcinogenesis. CCL2/CCR2 gene knockout mice and macrophage-specific PPARG gene knockout mice were respectively used to investigate the role of infiltration and polarization of TAMs in ESCC. CCL2-mediated monocyte chemotaxis was estimated in malignantly transformed Het-1A cells. THP-1 cells were used to simulate TAMs polarization in vitro. RNA-sequencing was performed to uncover the mechanism.

Results

Increasing expression of CCL2 correlated with TAMs accumulation in esophageal carcinogenesis, and they both predicts poor prognosis in ESCC cohort. Animal studies show blockade of CCL2-CCR2 axis strongly reduces tumor incidence by hindering TAMs recruitment and thereby potentiates the antitumor efficacy of CD8⁺ T cells in the tumor microenvironment. More importantly, M2 polarization increases PD-L2 expression in TAMs, resulting in immune evasion and tumor promotion through PD-1 signaling pathway.

Conclusion

This study highlights the role of CCL2-CCR2 axis in esophageal carcinogenesis. Our findings provide new insight into the mechanism of immune evasion mediated by TAMs in ESCC, suggesting the potential of TAMs-targeted strategies for ESCC prevention and immunotherapy.

Interleukin-33-nuclear factor-κB-CCL2 signaling pathway promotes progression of esophageal squamous cell carcinoma by directing regulatory T cells

Esophageal cancer is currently one of the most fatal cancers. However, there is no effective treatment. Increasing evidence suggests that interleukin (IL)‐33 has a significant role in tumor progression and metastasis. Currently, the underlying cellular and molecular mechanism of IL‐33 in promoting esophageal squamous cell carcinoma (ESCC) remains unclear. In this study, we investigated whether IL‐33 could induce the epithelial‐mesenchymal transition (EMT) in ESCC. Interleukin‐33 expression was examined in ESCC and corresponding adjacent normal tissues by immunohistochemistry and quantitative real‐time PCR experiments. Elevated IL‐33 levels were observed in ESCC tissues. Further in vitro experiments were undertaken to elucidate the effect of IL‐33 on migration and invasion in KYSE‐450 and Eca‐109 esophageal cancer cells. Knockdown of IL‐33 decreased the metastasis and invasion capacity in esophageal cancer cells, whereas IL‐33 overexpression showed the opposite effect. We then screened CCL2 which is a downstream molecule of IL‐33, and proved that IL‐33 could promote tumor development and metastasis by recruiting regulatory T cells (Tregs) through CCL2, and IL‐33 regulated the expression of CCL2 through transforming growth factor‐β in Treg cells. Knockdown of IL‐33 decreased the development of human ESCC xenografts in BALB/c nude mice. Collectively, we found that the IL‐33/nuclear factor‐κB/CCL2 pathway played an essential role in human ESCC progress. Hence, IL‐33 should be considered as an effective therapy target for ESCC.

Opposite Macrophage Polarization in Different Subsets of Ovarian Cancer: Observation from a Pilot Study

The role of the innate immune system in ovarian cancer is gaining importance. The relevance of tumor-associated macrophages (TAM) is insufficiently understood. In this pilot project, comprising the immunofluorescent staining of 30 biopsies taken from 24 patients with ovarian cancer, we evaluated the presence of total TAM (cluster of differentiation (CD) 68 expression), M1 (major histocompatibility complex (MHC) II expression), and M2 (anti-mannose receptor C type 1 (MRC1) expression), and the blood vessel diameter. We observed a high M1/M2 ratio in low-grade ovarian cancer compared to high-grade tumors, more total TAM and M2 in metastatic biopsies, and a further increase in total TAM and M2 at interval debulking, without beneficial effects of bevacizumab. The blood vessel diameter was indicative for M2 tumor infiltration (Spearman correlation coefficient of 0.65). These data mainly reveal an immune beneficial environment in low-grade ovarian cancer in contrast to high-grade serous ovarian cancer, where immune suppression is not altered by neoadjuvant therapy.

Drug delivery to macrophages: A review of targeting drugs and drug carriers to macrophages for inflammatory diseases

Macrophages play a key role in defending against foreign pathogens, healing wounds, and regulating tissue homeostasis. Driving this versatility is their phenotypic plasticity, which enables macrophages to respond to subtle cues in tightly coordinated ways. However, when this coordination is disrupted, macrophages can aid the progression of numerous diseases, including cancer, cardiovascular disease, and autoimmune disease. The central link between these disorders is aberrant macrophage polarization, which misguides their functional programs, secretory products, and regulation of the surrounding tissue microenvironment. As a result of their important and deterministic roles in both health and disease, macrophages have gained considerable attention as targets for drug delivery. Here, we discuss the role of macrophages in the initiation and progression of various inflammatory diseases, summarize the leading drugs used to regulate macrophages, and review drug delivery systems designed to target macrophages. We emphasize strategies that are approved for clinical use or are poised for clinical investigation. Finally, we provide a prospectus of the future of macrophage-targeted drug delivery systems.

SI-CLP inhibits the growth of mouse mammary adenocarcinoma by preventing recruitment of tumor-associated macrophages

Chitinase-like proteins (CLP) are chitin-binding proteins that lack chitin hydrolyzing activity, but possess cytokine-like and growth factor-like properties, and play crucial role in intercellular crosstalk. Both human and mice express two members of CLP family: YKL-40 and stabilin-1 interacting chitinase-like protein (SI-CLP). Despite numerous reports indicating the role of YKL-40 in the support of angiogenesis, tumor cell proliferation, invasion and metastasis, the role of its structurally related protein SI-CLP in cancer was not reported. Using gain-of-function approach, we demonstrate in the current study that the expression of recombinant SI-CLP in mouse TS/A mammary adenocarcinoma cells results in significant and persistent inhibition of in vivo tumor growth. Using quantitative immunohistochemistry, we show that on the cellular level this phenomenon is associated with reduced infiltration of tumor-associated macrophages (TAMs), CD4+ and FoxP3+ cells in SI-CLP expressing tumors. Gene expression analysis in TAM isolated from SI-CLP-expressing and control tumors demonstrated that SI-CLP does not affect macrophage phenotype. However, SI-CLP significantly inhibited migration of murine bone-marrow derived macrophages and human primary monocytes toward monocyte-recruiting chemokine CCL2 produced in the tumor microenvironment (TME). Mechanistically, SI-CLP did not affect CCL2/CCR2 interaction, but suppressed cytoskeletal rearrangements in response to CCL2. Altogether, our data indicate that SI-CLP functions as a tumor growth inhibitor in mouse breast cancer by altering cellular composition of TME and blocking cytokine-induced TAM recruitment. Taking into consideration weak to absent expression of SI-CLP in human breast cancer, it can be considered as a therapeutic protein to block TAM-mediated support of breast tumor growth.

The Role of Epithelial-to-Mesenchymal Plasticity in Ovarian Cancer Progression and Therapy Resistance

Ovarian cancer is the most lethal of all gynecologic malignancies and the eighth leading cause of cancer-related deaths among women worldwide. The main reasons for this poor prognosis are late diagnosis; when the disease is already in an advanced stage, and the frequent development of resistance to current chemotherapeutic regimens. Growing evidence demonstrates that apart from its role in ovarian cancer progression, epithelial-to-mesenchymal transition (EMT) can promote chemotherapy resistance. In this review, we will highlight the contribution of EMT to the distinct steps of ovarian cancer progression. In addition, we will review the different types of ovarian cancer resistance to therapy with particular attention to EMT-mediated mechanisms such as cell fate transitions, enhancement of cancer cell survival, and upregulation of genes related to drug resistance. Preclinical studies of anti-EMT therapies have yielded promising results. However, before anti-EMT therapies can be effectively implemented in clinical trials, more research is needed to elucidate the mechanisms leading to EMT-induced therapy resistance.

Chemotherapy and Inflammatory Cytokine Signalling in Cancer Cells and the Tumour Microenvironment

Cancer is the result of a cell's acquisition of a variety of biological capabilities or 'hallmarks' as outlined by Hanahan and Weinberg. These include sustained proliferative signalling, the ability to evade growth suppressors, resisting cell death, enabling replicative immortality, inducing angiogenesis, and the ability to invade other tissue and metastasize. More recently, the ability to escape immune destruction has been recognized as another important hallmark of tumours. It is suggested that genome instability and inflammation accelerates the acquisition of a variety of the above hallmarks. Inflammation, is a product of the body's response to tissue damage or pathogen invasion. It is required for tissue repair and host defense, but prolonged inflammation can often be the cause for disease. In a cancer patient, it is often unclear whether inflammation plays a protective or deleterious role in disease progression. Chemotherapy drugs can suppress tumour growth but also induce pathways in tumour cells that have been shown experimentally to support tumour progression or, in other cases, encourage an anti-tumour immune response. Thus, with the goal of better understanding the context under which each of these possible outcomes occurs, recent progress exploring chemotherapy-induced inflammatory cytokine production and the effects of cytokines on drug efficacy in the tumour microenvironment will be reviewed. The implications of chemotherapy on host and tumour cytokine pathways and their effect on the treatment of cancer patients will also be discussed.