CCL2 secreted from cancer-associated mesothelial cells promotes peritoneal metastasis of ovarian cancer cells through the P38-MAPK pathway

M2-like tumor-associated macrophage-secreted CCL2 facilitates gallbladder cancer stemness and metastasis

BACKGROUND

The predominant immune cells in solid tumors are M2-like tumor-associated macrophages (M2-like TAMs), which significantly impact the promotion of epithelial-mesenchymal transition (EMT) in tumors, enhancing stemness and facilitating tumor invasion and metastasis. However, the contribution of M2-like TAMs to tumor progression in gallbladder cancer (GBC) is partially known.

METHODS

Immunohistochemistry was used to evaluate the expression of M2-like TAMs and cancer stem cell (CSC) markers in 24 pairs of GBC and adjacent noncancerous tissues from patients with GBC. Subsequently, GBC cells and M2-like TAMs were co-cultured to examine the expression of CSC markers, EMT markers, and migratory behavior. Proteomics was performed on the culture supernatant of M2-like TAMs. The mechanisms underlying the induction of EMT, stemness, and metastasis in GBC by M2-like TAMs were elucidated using proteomics and transcriptomics. GBC cells were co-cultured with undifferentiated macrophages (M0) and analyzed. The therapeutic effect of gemcitabine combined with a chemokine (C-C motif) receptor 2 (CCR2) antagonist on GBC was observed in vivo.

RESULTS

The expression levels of CD68 and CD163 in M2-like TAMs and CD44 and CD133 in gallbladder cancer stem cells (GBCSCs) were increased and positively correlated in GBC tissues compared with those in neighboring noncancerous tissues. M2-like TAMs secreted a significant amount of chemotactic cytokine ligand 2 (CCL2), which activated the MEK/extracellular regulated protein kinase (ERK) pathway and enhanced SNAIL expression after binding to the receptor CCR2 on GBC cells. Activation of the ERK pathway caused nuclear translocation of ELK1, which subsequently led to increased SNAIL expression. GBCSCs mediated the recruitment and polarization of M0 into M2-like TAMs within the GBC microenvironment via CCL2 secretion. In the murine models, the combination of a CCR2 antagonist and gemcitabine efficiently inhibited the growth of subcutaneous tumors in GBC.

CONCLUSIONS

The interaction between M2-like TAMs and GBC cells is mediated by the chemokine CCL2, which activates the MEK/ERK/ELK1/SNAIL pathway in GBC cells, promoting EMT, stemness, and metastasis. A combination of a CCR2 inhibitor and gemcitabine effectively suppressed the growth of subcutaneous tumors. Consequently, our study identified promising therapeutic targets and strategies for treating GBC.

The effects of tumor-derived supernatants (TDS) on cancer cell progression: A review and update on carcinogenesis and immunotherapy

Tumors can produce bioactive substances called tumor-derived supernatants (TDS) that modify the immune response in the host body. This can result in immunosuppressive effects that promote the growth and spread of cancer. During tumorigenesis, the exudation of these substances can disrupt the function of immune sentinels in the host and reinforce the support for cancer cell growth. Tumor cells produce cytokines, growth factors, and proteins, which contribute to the progression of the tumor and the formation of premetastatic niches. By understanding how cancer cells influence the host immune system through the secretion of these factors, we can gain new insights into cancer diagnosis and therapy.

CCL2 regulated by the CTBP1-AS2/miR-335-5p axis promotes hemangioma progression and angiogenesis

CONTEXT

Hemangioma (HA) is a benign vascular neoplasm that can lead to permanent scarring. C-C motif chemokine ligand 2 (CCL2) plays a crucial role in facilitating growth and angiogenesis during HA progression. However, the mechanism regulating CCL2 in HA remains poorly elucidated.

OBJECTIVE

To elucidate the mechanism regulating CCL2 in HA.

METHODS

Quantitative real-time polymerase chain reaction (RT-qPCR) was employed to determine the expression levels of CCL2, long noncoding RNA (lncRNA) CTBP1 divergent transcript (CTBP1-AS2), and microRNAs (miRNAs). Proliferation, migration, invasion, and angiogenic abilities of human HA endothelial cells (HemECs) were assessed using cell counting kit-8 (CCK-8), colony formation, flow cytometry, transwell, and tube formation assays. Bioinformatics analysis, RNA pull-down, and luciferase reporter assays were conducted to investigate whether CCL2 targets miR-335-5p. Additionally, rescue experiments were performed in this study.

RESULTS

CCL2 expression was markedly upregulated in HemECs. CCL2 promoted HA cell proliferation, migration, invasion, and angiogenesis while inhibiting apoptosis. CCL2 was directly targeted by miR-335-5p. Additionally, we found that CTBP1-AS2 could function as a competing endogenous RNA (ceRNA) to sponge miR-335-5p, thereby upregulating CCL2.

CONCLUSION

Our findings suggest that targeting the CTBP1-AS2/miR-335-5p/CCL2 axis may hold promise as a therapeutic strategy for HA.

Hydrophobic surface induced pro-metastatic cancer cells for in vitro extravasation models

In vitro vascularized cancer models utilizing microfluidics have emerged as a promising tool for mechanism study and drug screening. However, the lack of consideration and preparation methods for cancer cellular sources that are capable of adequately replicating the metastatic features of circulating tumor cells contributed to low relevancy with in vivo experimental results. Here, we show that the properties of cancer cellular sources have a considerable impact on the validity of the in vitro metastasis model. Notably, with a hydrophobic surface, we can create highly metastatic spheroids equipped with aggressive invasion, endothelium adhesion capabilities, and activated metabolic features. Combining these metastatic spheroids with the well-constructed microfluidic-based extravasation model, we validate that these metastatic spheroids exhibited a distinct extravasation response to epidermal growth factor (EGF) and normal human lung fibroblasts compared to the 2D cultured cancer cells, which is consistent with the previously reported results of in vivo experiments. Furthermore, the applicability of the developed model as a therapeutic screening platform for cancer extravasation is validated through profiling and inhibition of cytokines. We believe this model incorporating hydrophobic surface-cultured 3D cancer cells provides reliable experimental data in a clear and concise manner, bridging the gap between the conventional in vitro models and in vivo experiments.

Tianhuang formula ameliorates liver fibrosis by inhibiting CCL2-CCR2 axis and MAPK/NF-κB signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

In the progression of chronic liver diseases, liver fibrosis is a reversible pathophysiologic event for liver diseases prognosis and risk of cirrhosis. Liver injury factors of different etiologies mediate this process. There is still a lack of effective medications for treating liver fibrosis. Additionally, the ameliorative effects of traditional herbs on liver fibrosis have been commonly reported. Tianhuang formula (THF) is a drug combination consisting of 2 traditional Chinese herbs, which has been showing significant improvement in metabolic liver diseases. However, the hepatoprotective effect and mechanism of THF in ameliorating liver fibrosis are still unclear.

AIM OF THE STUDY

This study aimed to investigate the effects of THF on carbon tetrachloride (CCl4)-induced and methionine-choline-deficient (MCD) diet-induced liver fibrosis model and to reveal the potential mechanisms. It can provide experimental evidence for THF as a therapeutic candidate for liver fibrosis.

MATERIALS AND METHODS

In this study, CCl4-induced mice were treated with THF (80 mg/kg, 160 mg/kg) or Fuzheng Huayu (FZHY) capsules (4.8 g/kg) for 6 weeks. MCD-induced mice received the same doses of THF or FZHY for 4 weeks. FZHY is used as a comparative study in these two models. Following that, using kit reagents detected changes in relevant serum and liver biochemical indicators. Histological changes in mouse liver were measured by staining of H&E and Sirius Red. The markers expression of liver fibrosis and inflammation were detected using qRT-PCR, western blotting and immunohistochemical staining analysis. The potential regulatory mechanism of THF to ameliorate liver fibrosis was performed by RNA-sequencing analysis. Finally, the analysis results were verified by immunofluorescence co-staining, qRT-PCR and western blotting.

RESULTS

Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and hepatic triglyceride (TG) levels in CCl4 and MCD-induced liver fibrosis mice were significantly improved after THF treatment. Meanwhile, the expression of fibrosis and inflammation markers were significantly suppressed. Furthermore, THF downregulated the expression of the macrophage marker CD68. According to RNA-sequencing analysis, we found the CCL2-CCR2 axis and MAPK/NF-κB as the potential signaling pathway for THF against liver fibrosis.

CONCLUSION

This study revealed that THF ameliorated liver injury, inflammation and fibrotic process by inhibiting CCL2-CCR2 axis and its downstream MAPK/NF-κB signaling pathway.

Mechanisms of carboplatin- and paclitaxel-dependent induction of premature senescence and pro-cancerogenic conversion of normal peritoneal mesothelium and fibroblasts

Carboplatin (CPT) and paclitaxel (PCT) are the optimal non-surgical treatment of epithelial ovarian cancer (EOC). Although their growth-restricting influence on EOC cells is well known, their impact on normal peritoneal cells, including mesothelium (PMCs) and fibroblasts (PFBs), is poorly understood. Here, we investigated whether, and if so, by what mechanism, CPT and PCT induce senescence of omental PMCs and PFBs. In addition, we tested whether PMC and PFB exposure to the drugs promotes the development of a pro-cancerogenic phenotype. The results showed that CPT and PCT induce G2/M growth arrest-associated senescence of normal peritoneal cells and that the strongest induction occurs when the drugs act together. PMCs senesce telomere-independently with an elevated p16 level and via activation of AKT and STAT3. In PFBs, telomeres shorten along with an induction of p21 and p53, and their senescence proceeds via the activation of ERK1/2. Oxidative stress in CPT + PCT-treated PMCs and PFBs is extensive and contributes causatively to their premature senescence. Both PMCs and PFBs exposed to CPT + PCT fuel the proliferation, migration, and invasion of established (A2780, OVCAR-3, SKOV-3) and primary EOCs, and this activity is linked with an overproduction of multiple cytokines altering the cancer cell transcriptome and controlled by p38 MAPK, NF-κB, STAT3, Notch1, and JAK1. Collectively, our findings indicate that CPT and PCT lead to iatrogenic senescence of normal peritoneal cells, which paradoxically and opposing therapeutic needs alters their phenotype towards pro-cancerogenic. It cannot be excluded that these adverse outcomes of chemotherapy may contribute to EOC relapse in the case of incomplete tumor eradication and residual disease initiation. © 2023 The Pathological Society of Great Britain and Ireland.

The cell stress and immunity cycle in cancer: Toward next generation of cancer immunotherapy

The cellular stress and immunity cycle is a cornerstone of organismal homeostasis. Stress activates intracellular and intercellular communications within a tissue or organ to initiate adaptive responses aiming to resolve the origin of this stress. If such local measures are unable to ameliorate this stress, then intercellular communications expand toward immune activation with the aim of recruiting immune cells to effectively resolve the situation while executing tissue repair to ameliorate any damage and facilitate homeostasis. This cellular stress-immunity cycle is severely dysregulated in diseased contexts like cancer. On one hand, cancer cells dysregulate the normal cellular stress responses to reorient them toward upholding growth at all costs, even at the expense of organismal integrity and homeostasis. On the other hand, the tumors severely dysregulate or inhibit various components of organismal immunity, for example, by facilitating immunosuppressive tumor landscape, lowering antigenicity, and increasing T-cell dysfunction. In this review we aim to comprehensively discuss the basis behind tumoral dysregulation of cellular stress-immunity cycle. We also offer insights into current understanding of the regulators and deregulators of this cycle and how they can be targeted for conceptualizing successful cancer immunotherapy regimen.

Cancer-Associated Fibroblast-Induced Remodeling of Tumor Microenvironment in Recurrent Bladder Cancer

Bladder carcinoma (BC) recurrence is a major clinical challenge, and targeting the tumor microenvironment (TME) is a promising therapy. However, the relationship between individual TME components, particularly cancer-associated fibroblasts (CAFs), and tumor recurrence is unclear. Here, TME heterogeneity in primary and recurrent BC is investigated using single-cell RNA sequence profiling of 62 460 cells. Two cancer stem cell (CSC) subtypes are identified in recurrent BC. An inflammatory CAF subtype, ICAM1+ iCAFs, specifically associated with BC recurrence is also identified. iCAFs are found to secrete FGF2, which acts on the CD44 receptor of rCSC-M, thereby maintaining tumor stemness and epithelial-mesenchymal transition. Additionally, THBS1+ monocytes, a group of myeloid-derived suppressor cells (MDSCs), are enriched in recurrent BC and interacted with CAFs. ICAM1+ iCAFs are found to secrete CCL2, which binds to CCR2 in MDSCs. Moreover, elevated STAT3, NFKB2, VEGFA, and CTGF levels in iCAFs reshape the TME in recurrent tumors. CCL2 inhibition in an in situ BC mouse model suppressed tumor growth, decreased MDSCs and Tregs, and fostered tumor immune suppression. The study results highlight the role of iCAFs in TME cell-cell crosstalk during recurrent BC. The identification of pivotal signaling factors driving BC relapse is promising for the development of novel therapies.

Insights into the tumor-stromal-immune cell metabolism cross talk in ovarian cancer

The ovarian cancer tumor microenvironment (TME) consists of a constellation of abundant cellular components, extracellular matrix, and soluble factors. Soluble factors, such as cytokines, chemokines, structural proteins, extracellular vesicles, and metabolites, are critical means of noncontact cellular communication acting as messengers to convey pro- or antitumorigenic signals. Vast advancements have been made in our understanding of how cancer cells adapt their metabolism to meet environmental demands and utilize these adaptations to promote survival, metastasis, and therapeutic resistance. The stromal TME contribution to this metabolic rewiring has been relatively underexplored, particularly in ovarian cancer. Thus, metabolic activity alterations in the TME hold promise for further study and potential therapeutic exploitation. In this review, we focus on the cellular components of the TME with emphasis on 1) metabolic signatures of ovarian cancer; 2) understanding the stromal cell network and their metabolic cross talk with tumor cells; and 3) how stromal and tumor cell metabolites alter intratumoral immune cell metabolism and function. Together, these elements provide insight into the metabolic influence of the TME and emphasize the importance of understanding how metabolic performance drives cancer progression.

Cancer-mesothelial and cancer-macrophage interactions in the ovarian cancer microenvironment

The metastatic ovarian cancer microenvironment is characterized by an intricate interaction network between cancer cells and host cells. This complex heterotypic cancer-host cell crosstalk results in an environment that promotes cancer cell metastasis and treatment resistance, leading to poor patient prognosis and survival. In this review, we focus on two host cell types found in the ovarian cancer microenvironment: mesothelial cells and tumor-associated macrophages. Mesothelial cells make up the protective lining of organs in the abdominal cavity. Cancer cells attach and invade through the mesothelial monolayer to form metastatic lesions. Crosstalk between mesothelial and cancer cells can contribute to metastatic progression and chemotherapy resistance. Tumor-associated macrophages are the most abundant immune cell type in the ovarian cancer microenvironment with heterogeneous subpopulations exhibiting protumor or antitumor functions. Macrophage reprogramming toward a protumor or antitumor state can be influenced by chemotherapy and communication with cancer cells, resulting in cancer cell invasion and treatment resistance. A better understanding of cancer-mesothelial and cancer-macrophage crosstalk will uncover biomarkers of metastatic progression and therapeutic targets to restore chemotherapy sensitivity.

Vascular Dysfunctions Contribute to the Long-Term Cognitive Deficits Following COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a single-stranded RNA virus and a member of the corona virus family, primarily affecting the upper respiratory system and the lungs. Like many other respiratory viruses, SARS-CoV-2 can spread to other organ systems. Apart from causing diarrhea, another very common but debilitating complication caused by SARS-CoV-2 is neurological symptoms and cognitive difficulties, which occur in up to two thirds of hospitalized COVID-19 patients and range from shortness of concentration and overall declined cognitive speed to executive or memory function impairment. Neuro-cognitive dysfunction and "brain fog" are frequently present in COVID-19 cases, which can last several months after the infection, leading to disruption of daily life. Cumulative evidence suggests that SARS-CoV-2 affects vasculature in the extra-pulmonary systems directly or indirectly, leading to impairment of endothelial function and even multi-organ damage. The post COVID-19 long-lasting neurocognitive impairments have not been studied fully and their underlying mechanism remains elusive. In this review, we summarize the current understanding of the effects of COVID-19 on vascular dysfunction and how vascular dysfunction leads to cognitive impairment in patients.

Cancer-associated mesothelial cells are regulated by the anti-Müllerian hormone axis

Cancer-associated mesothelial cells (CAMCs) in the tumor microenvironment are thought to promote growth and immune evasion. We find that, in mouse and human ovarian tumors, cancer cells express anti-Müllerian hormone (AMH) while CAMCs express its receptor AMHR2, suggesting a paracrine axis. Factors secreted by cancer cells induce AMHR2 expression during their reprogramming into CAMCs in mouse and human in vitro models. Overexpression of AMHR2 in the Met5a mesothelial cell line is sufficient to induce expression of immunosuppressive cytokines and growth factors that stimulate ovarian cancer cell growth in an AMH-dependent way. Finally, syngeneic cancer cells implanted in transgenic mice with Amhr2-/- CAMCs grow significantly slower than in wild-type hosts. The cytokine profile of Amhr2-/- tumor-bearing mice is altered and their tumors express less immune checkpoint markers programmed-cell-death 1 (PD1) and cytotoxic T lymphocyte-associated protein 4 (CTLA4). Taken together, these data suggest that the AMH/AMHR2 axis plays a critical role in regulating the pro-tumoral function of CAMCs in ovarian cancer.

Vemurafenib induces a noncanonical senescence-associated secretory phenotype in melanoma cells which promotes vemurafenib resistance

More than one half melanoma patients have BRAF gene mutation. BRAF inhibitor vemurafenib is an effective medication for these patients. However, acquired resistance is generally inevitable, the mechanisms of which are not fully understood. Cell senescence and senescence-associated secretory phenotype (SASP) are involved in extensive biological functions. This study was designed to explore the possible role of senescent cells in vemurafenib resistance. The results showed that vemurafenib treatment induced BRAF-mutant but not wild-type melanoma cells into senescence, as manifested by positive β-galactosidase staining, cell cycle arrest, enlarged cellular morphology, and cyclin D1/p-Rb pathway inhibition. However, the senescent cells induced by vemurafenib (SenV) did not display DNA damage response, p53/p21 pathway activation, reactive oxygen species accumulation, decline of mitochondrial membrane potential, or secretion of canonical SASP cytokines. Instead, SenV released other cytokines, including CCL2, TIMP2, and NGFR, to protect normal melanoma cells from growth inhibition upon vemurafenib treatment. Xenograft experiments further confirmed that vemurafenib induced melanoma cells into senescence in vivo. The results suggest that vemurafenib can induce robust senescence in BRAF^V600E melanoma cells, leading to the release of resistance-conferring cytokines. Both the senescent cells and the resistant cytokines could be potential targets for tackling vemurafenib resistance.

"DEPHENCE" system-a novel regimen of therapy that is urgently needed in the high-grade serous ovarian cancer-a focus on anti-cancer stem cell and anti-tumor microenvironment targeted therapies

Ovarian cancer, especially high-grade serous type, is the most lethal gynecological malignancy. The lack of screening programs and the scarcity of symptomatology result in the late diagnosis in about 75% of affected women. Despite very demanding and aggressive surgical treatment, multiple-line chemotherapy regimens and both approved and clinically tested targeted therapies, the overall survival of patients is still unsatisfactory and disappointing. Research studies have recently brought some more understanding of the molecular diversity of the ovarian cancer, its unique intraperitoneal biology, the role of cancer stem cells, and the complexity of tumor microenvironment. There is a growing body of evidence that individualization of the treatment adjusted to the molecular and biochemical signature of the tumor as well as to the medical status of the patient should replace or supplement the foregoing therapy. In this review, we have proposed the principles of the novel regimen of the therapy that we called the "DEPHENCE" system, and we have extensively discussed the results of the studies focused on the ovarian cancer stem cells, other components of cancer metastatic niche, and, finally, clinical trials targeting these two environments. Through this, we have tried to present the evolving landscape of treatment options and put flesh on the experimental approach to attack the high-grade serous ovarian cancer multidirectionally, corresponding to the "DEPHENCE" system postulates.

CC Chemokine 2 Promotes Ovarian Cancer Progression through the MEK/ERK/MAP3K19 Signaling Pathway

Ovarian cancer is a gynecological tumor with an incidence rate lower than those of other gynecological tumor types and the second-highest death rate. CC chemokine 2 (CCL2) is a multifunctional factor associated with the progression of numerous cancers. However, the effect of CCL2 on ovarian cancer progression is unclear. Here, we found that exogenous CCL2 and the overexpression of CCL2 promoted the proliferation and metastasis of ovarian cancer cells. On the other hand, CCL2 knockdown via CRISPR/Cas9 inhibited ovarian cancer cell proliferation, migration, and invasion. The present study demonstrated that mitogen-activated protein three kinase 19 (MAP3K19) was the key CCL2 target for regulating ovarian cancer progression through transcriptome sequencing. Additionally, MAP3K19 knockout inhibited ovarian cancer cell proliferation, migration, and invasion. Furthermore, CCL2 increased MAP3K19 expression by activating the mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway. The present study showed the correlation between CCL2 and ovarian cancer, suggesting that CCL2 may be a novel target for ovarian cancer therapy.

Cancer-associated mesothelial cell-derived ANGPTL4 and STC1 promote the early steps of ovarian cancer metastasis

Ovarian cancer (OvCa) preferentially metastasizes in association with mesothelial cell-lined surfaces. We sought to determine if mesothelial cells are required for OvCa metastasis and detect alterations in mesothelial cell gene expression and cytokine secretion upon interaction with OvCa cells. Using omental samples from patients with high-grade serous OvCa and mouse models with Wt1-driven GFP-expressing mesothelial cells, we validated the intratumoral localization of mesothelial cells during human and mouse OvCa omental metastasis. Removing mesothelial cells ex vivo from human and mouse omenta or in vivo using diphtheria toxin-mediated ablation in Msln-Cre mice significantly inhibited OvCa cell adhesion and colonization. Human ascites induced angiopoietin-like 4 (ANGPTL4) and stanniocalcin 1 (STC1) expression and secretion by mesothelial cells. Inhibition of STC1 or ANGPTL4 via RNAi obstructed OvCa cell-induced mesothelial cell to mesenchymal transition while inhibition of ANGPTL4 alone obstructed OvCa cell-induced mesothelial cell migration and glycolysis. Inhibition of mesothelial cell ANGPTL4 secretion via RNAi prevented mesothelial cell-induced monocyte migration, endothelial cell vessel formation, and OvCa cell adhesion, migration, and proliferation. In contrast, inhibition of mesothelial cell STC1 secretion via RNAi prevented mesothelial cell-induced endothelial cell vessel formation and OvCa cell adhesion, migration, proliferation, and invasion. Additionally, blocking ANPTL4 function with Abs reduced the ex vivo colonization of 3 different OvCa cell lines on human omental tissue explants and in vivo colonization of ID8p53-/-Brca2-/- cells on mouse omenta. These findings indicate that mesothelial cells are important to the initial stages of OvCa metastasis and that the crosstalk between mesothelial cells and the tumor microenvironment promotes OvCa metastasis through the secretion of ANGPTL4.

Macrophages Promote Ovarian Cancer-Mesothelial Cell Adhesion by Upregulation of ITGA2 and VEGFC in Mesothelial Cells

Ovarian cancer is a metastatic disease that frequently exhibits extensive peritoneal dissemination. Recent studies have revealed that noncancerous cells inside the tumor microenvironment, such as macrophages and mesothelial cells, may play a role in ovarian cancer metastasis. In this study, we found that human ovarian cancer cells (A2780 and SKOV3) adhered more to human mesothelial Met5A cells stimulated by macrophages (M-Met5A) in comparison to unstimulated control Met5A cells. The mRNA sequencing revealed that 94 adhesion-related genes, including FMN1, ITGA2, COL13A1, VEGFC, and NRG1, were markedly upregulated in M-Met5A cells. Knockdown of ITGA2 and VEGFC in M-Met5A cells significantly inhibited the adhesion of ovarian cancer cells. Inhibition of the JNK and Akt signaling pathways suppressed ITGA2 and VEGFC expression in M-Met5A cells as well as ovarian cancer-mesothelial cell adhesion. Furthermore, increased production of CC chemokine ligand 2 (CCL2) and CCL5 by macrophages elevated ovarian cancer-mesothelial cell adhesion. These findings imply that macrophages may play a significant role in ovarian cancer-mesothelial cell adhesion by inducing the mesothelial expression of adhesion-related genes via the JNK and Akt pathways.

Laminins in tumor-derived exosomes upregulated by ETS1 reprogram omental macrophages to promote omental metastasis of ovarian cancer

Tumor-derived exosomes participate in omental metastatic colonization of ovarian cancer by inducing an adaptive response in the tumor microenvironment. However, cell-cell communication via exosomes between primary tumor cells and the microenvironment of distant omentum and the mechanism of pre-metastatic niche formation are poorly understood. Here, we demonstrated that ETS1-overexpressing ovarian cancer cells secreted larger exosomes with higher laminin levels. In addition, ovarian cancer exosomes could be taken up by omental macrophages through integrin and laminin interaction. Compared with control exosomes, exosomes derived from ETS1-overexpressing ovarian cancer cells (LV-ETS1 Exos) stimulated the polarization of more macrophages toward the M2 phenotype (CD163 marker), as well as the production of more CXCL5 and CCL2 in macrophages, via integrin αvβ5/AKT/Sp1 signaling. In vivo experiments showed that LV-ETS1 Exos promoted omental metastasis of ovarian cancer by mediating the tumor-promoting effect of macrophages, which could be neutralized by integrin ανβ5 inhibitor cilengitide. These results indicated that ETS1 could drive ovarian cancer cells to release exosomes with higher laminin levels, thereby accelerating the exosome-mediated pro-metastatic effects of omental macrophages via the integrin αvβ5/AKT/Sp1 signaling pathway, and the integrin ανβ5 inhibitor cilengitide could inhibit omental metastasis of ovarian cancer driven by tumor-derived exosomes.

The Interface of Tumour-Associated Macrophages with Dying Cancer Cells in Immuno-Oncology

Tumour-associated macrophages (TAMs) are essential players in the tumour microenvironment (TME) and modulate various pro-tumorigenic functions such as immunosuppression, angiogenesis, cancer cell proliferation, invasion and metastasis, along with resistance to anti-cancer therapies. TAMs also mediate important anti-tumour functions and can clear dying cancer cells via efferocytosis. Thus, not surprisingly, TAMs exhibit heterogeneous activities and functional plasticity depending on the type and context of cancer cell death that they are faced with. This ultimately governs both the pro-tumorigenic and anti-tumorigenic activity of TAMs, making the interface between TAMs and dying cancer cells very important for modulating cancer growth and the efficacy of chemo-radiotherapy or immunotherapy. In this review, we discuss the interface of TAMs with cancer cell death from the perspectives of cell death pathways, TME-driven variations, TAM heterogeneity and cell-death-inducing anti-cancer therapies. We believe that a better understanding of how dying cancer cells influence TAMs can lead to improved combinatorial anti-cancer therapies, especially in combination with TAM-targeting immunotherapies.

Prognostic biomarker MCP-4 triggers epithelial-mesenchymal transition via the p38 MAPK pathway in ovarian cancer

BACKGROUND

Monocyte chemoattractant protein-4 (MCP-4/CCL13) is a proinflammatory factor that is overexpressed in various malignant tumors and may play an important role in tumor progression and metastasis. However, its role and mechanism of action in ovarian cancer remains unknown.

METHODS

Immunohistochemistry (IHC) was performed to detect the expression of MCP-4 in ovarian cancer tissues, and the effect of MCP-4 on patient survival and prognosis was analyzed. Overexpression and suppression of MCP-4 in ovarian cancer cell lines were then established, and their effects on cell invasion, migration, and apoptosis were studied. ES-2 cell lines were employed to establish a peritoneal dissemination model in nude mice. Western blotting was performed to detect the expression of epithelial mesenchymal transition (EMT) markers and the p38 mitogen-activated protein kinase (p38 MAPK) signaling pathway.

RESULTS

MCP-4 was highly expressed in ovarian cancer tissues and its expression level was related to the prognosis of patients with ovarian cancer. MCP-4 overexpression promoted the migration and invasion of ovarian cancer cells but inhibited apoptosis. MCP-4 overexpression increased the expression of MMP-2, MMP-9, N-cadherin, vimentin and Bcl2/Bax and decreased the expression of E-cadherin. MCP-4 overexpression increased the phosphorylation of the p38 MAPK pathway. The inhibition of MCP-4 expression indicated an opposite trend. In vivo experiments have also confirmed that MCP-4 overexpression can promote metastasis of ovarian cancer.

CONCLUSION

MCP-4 promotes ovarian cancer progression through the p38 MAPK signaling pathway, and may be a potential biomarker and therapeutic target for ovarian cancer.

Role of CC-chemokine ligand 2 in gynecological cancer

Gynecological cancer is one of the most severe diseases that threaten the lives and health of women worldwide. Its incidence rate increases with each passing year and becomes more prevalent among young people. The prognosis of gynecological cancer remains poor despite significant advances in surgical removal and systemic chemotherapy. Several chemokines play a role in the progression of gynecologic cancers. CCL2 (CC-chemokine ligand 2), also termed MCP-1 (monocyte chemotactic protein 1), plays a significant physiological role in monocyte cell migration and the inflammatory response. Recent studies have demonstrated that CCL2 plays a pro-tumorigenic function in the tumor microenvironment. According to previous studies, CCL2 plays a significant role in the occurrence and development of gynecological cancers. Furthermore, recent studies noted that CCL2 could be a potential diagnostic biomarker and prognostic predictor. The purpose of this paper is to review the role of CCL2 in the occurrence and development of gynecological cancers and to discuss the potential therapeutic strategy of CCL2 for gynecological cancers, with a primary focus on breast cancer, ovarian cancer, cervical cancer, and endometrial cancer.

The role of cancer-associated mesothelial cells in the progression and therapy of ovarian cancer

Ovarian cancer is currently one of the most common malignant tumors in females with poor survival rates around the world, killing about 200,000 women each year. Although great progress has been made in treatment, most patients receiving first-line therapy experience tumor recurrence. The tumor microenvironment plays an important role in regulating the progression and prognosis of ovarian cancer. Cancer-associated mesothelial cells are the main cell population in the tumor microenvironment, which affect the progression, prognosis and chemical resistance of ovarian cancer. Cancer-associated mesothelial cells can also interact with other microenvironmental components, such as exosomes, macrophages, and adipocytes. Some studies have developed drugs targeting cancer-associated mesothelial cells in ovarian cancer to evaluate the therapeutic efficiency. In this review we highlighted the key role of cancer-associated mesothelial cells in the progression and prognosis of ovarian cancer. We also described the progress of cancer-associated mesothelial cells targeted therapy for ovarian cancer. Continued insight into the role of cancer-associated mesothelial cells in ovarian cancer will potentially contribute to the development of new and effective therapeutic regiments.

Serum CCL2 Is a Prognostic Biomarker for Non-Metastatic Castration-Sensitive Prostate Cancer

Purpose: Prostate-specific antigen (PSA) is a useful prostate cancer (PC) biomarker, but some cases reported that PSA does not correlate with the Gleason score. Serum chemokine (CC motif) ligand 2 (CCL2) has been reported to be a potential complementary PSA biomarker, but it remains unclear whether it can be applied to non-metastatic castration-sensitive prostate cancer (nmCSPC) or each section of the stages. Serum CCL2′s usefulness was investigated as a prognostic nmCSPC biomarker in this study. Methods: Serum samples were collected from 379 patients who underwent prostate biopsy at Kanazawa University Hospital from 2007 to 2013. A total of 230 patients with nmCSPC were included in this study of the 255 patients with histologically diagnosed prostate cancer. The serum CCL2 efficacy as a prognostic nmCSPC biomarker was investigated retrospectively. Results: An independent significant predictor of worse OS was CCL2 ≥ 280 pg/dL and CRP ≥ 0.5 mg/dL in multivariate analysis. Gleason score ≥ 8 and CCL2 ≥ 280 pg/dL were independent significant predictors of CRPC-free survival (CFS) worsening in multivariate analysis. Serum CCL2 was a predictive biomarker for OS and CFS in nmCSPC. Furthermore, CCL2 ≥ 280 pg/mL patients had significantly worse visceral metastasis-free survival than those with CCL2 < 280 pg/mL. Conclusion: This study is the first to demonstrate serum CCL2 utility as a biomarker to predict OS and CFS in nmCSPC.

Overexpression of NCAPG in ovarian cancer is associated with ovarian cancer proliferation and apoptosis via p38 MAPK signaling pathway

Background

Non-SMC condensin I complex subunit G (NCAPG), a member of the subunit of condensin complex, is significantly overexpressed in various cancers and involved in the pathogenesis of cancers. However, the roles of NCAPG in ovarian cancer remain unclear.

Methods

The mRNA expression, overall survival, and disease-free survival of NCAPG in ovarian cancer were analyzed by GEPIA and KM plotter database, and the expression levels of NCAPG in OC tissues and cell lines were determined by qPCR and immunohistochemistry analysis. shRNA targeting NCAPG gene (sh-NCAPG) was utilized to knock down NCAPG expression in OVCAR3 and SKOV3 cells. Subsequently, CCK-8 assay, colony formation assay, transwell invasion assay and flow cytometric analysis were performed to detect the effect of NCAPG on OC cell proliferation, apoptosis, and invasion. Finally, western blot assays were performed to detect the mechanism of NCAPG in ovarian cancer.

Results

Analysis using GEPIA and KM plotter database showed NCAPG was upregulated in ovarian cancer and negatively associated with the survival of OC patients. qPCR and immunohistochemistry analysis confirmed it was highly expressed in both ovarian cancer tissues and cells. The silencing of NCAPG inhibited OC cell proliferation and invasion, and induced cell apoptosis. Additionally, flow cytometric analysis revealed that NCAPG knockdown arrested the cell cycle at G2 and S phases. Furthermore, we also found that downregulation of NCAPG could suppress OC cell proliferation and invasion via activating the p38 MAPK signaling pathway.

Conclusion

Our results suggest that NCAPG exhibits an important role in the development and progression of ovarian cancer and implicates NCAPG as a potential therapeutic target in ovarian cancer.

Peritoneal Restoration by Repurposing Vitamin D Inhibits Ovarian Cancer Dissemination via Blockade of the TGF-β1/Thrombospondin-1 Axis

PURPOSE

Ovarian cancer (OvCa), a lethal gynecological malignancy, disseminates to the peritoneum. Mesothelial cells (MCs) act as barriers in the abdominal cavity, preventing the adhesion of cancer cells. However, in patients with OvCa, they are transformed into cancer-associated mesothelial cells (CAMs) via mesenchymal transition and form a favorable microenvironment for tumors to promote metastasis. However, attempts for restoring CAMs to their original state have been limited. Here, we investigated whether inhibition of mesenchymal transition and restoration of MCs by vitamin D suppressed the OvCa dissemination in vitro and in vivo.

METHODS

The effect of vitamin D on the mutual association of MCs and OvCa cells was evaluated using in vitro coculture models and in vivo using a xenograft model.

RESULTS

Vitamin D restored the CAMs, and thrombospondin-1 (component of the extracellular matrix that is clinically associated with poor prognosis and is highly expressed in peritoneally metastasized OvCa) was found to promote OvCa cell adhesion and proliferation. Mechanistically, TGF-β1 secreted from OvCa cells enhanced thrombospondin-1 expression in CAMs via Smad-dependent TGF-β signaling. Vitamin D inhibited mesenchymal transition in MCs and suppressed thrombospondin-1 expression via vitamin D receptor/Smad3 competition, contributing to the marked reduction in peritoneal dissemination in vivo. Importantly, vitamin D restored CAMs from a stabilized mesenchymal state to the epithelial state and normalized thrombospondin-1 expression in preclinical models that mimic cancerous peritonitis in vivo.

CONCLUSIONS

MCs are key players in OvCa dissemination and peritoneal restoration and normalization of thrombospondin-1 expression by vitamin D may be a novel strategy for preventing OvCa dissemination.

Functional Roles of Chemokine Receptor CCR2 and Its Ligands in Liver Disease

Chemokines are a family of cytokines that orchestrate the migration and positioning of immune cells within tissues and are critical for the function of the immune system. CCR2 participates in liver pathology, including acute liver injury, chronic hepatitis, fibrosis/cirrhosis, and tumor progression, by mediating the recruitment of immune cells to inflammation and tumor sites. Although a variety of chemokines have been well studied in various diseases, there is no comprehensive review presenting the roles of all known chemokine ligands of CCR2 (CCL2, CCL7, CCL8, CCL12, CCL13, CCL16, and PSMP) in liver disease, and this review aims to fill this gap. The introduction of each chemokine includes its discovery, its corresponding chemotactic receptors, physiological functions and roles in inflammation and tumors, and its impact on different immune cell subgroups.

High-Fat Diet-Induced Obese Effects of Adipocyte-Specific CXCR2 Conditional Knockout in the Peritoneal Tumor Microenvironment of Ovarian Cancer

Obesity contributes to ovarian cancer (OC) progression via tumorigenic chemokines. Adipocytes and OC cells highly express CXCR2, and its ligands CXCL1/8, respectively, indicating that the CXCL1/8-CXCR2 axis is a molecular link between obesity and OC. Here, we investigated how the adipocyte-specific CXCR2 conditional knockout (cKO) affected the peritoneal tumor microenvironment of OC in a high-fat diet (HFD)-induced obese mouse model. We first generated adipocyte-specific CXCR2 cKO in mice: adipose tissues were not different in crown-like structures and adipocyte size between the wild-type (WT) and cKO mice but expressed lower levels of CCL2/6 compared to the obese WT mice. HFD-induced obese mice had a shorter survival time than lean mice. Particularly, obese WT and cKO mice developed higher tumors and ascites burdens, respectively. The ascites from the obese cKO mice showed increased vacuole clumps but decreased the floating tumor burden, tumor-attached macrophages, triglyceride, free fatty acid, CCL2, and TNF levels compared to obese WT mice. A tumor analysis revealed that obese cKO mice attenuated inflammatory areas, PCNA, and F4/80 compared to obese WT mice, indicating a reduced tumor burden, and there were positive relationships between the ascites and tumor parameters. Taken together, the adipocyte-specific CXCR2 cKO was associated with obesity-induced ascites despite a reduced tumor burden, likely altering the peritoneal tumor microenvironment of OC.

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.

Roles of CCL2-CCR2 Axis in the Tumor Microenvironment

Chemokines are a small family of cytokines that were first discovered as chemotactic factors in leukocytes during inflammation, and reports on the relationship between chemokines and cancer progression have recently been increasing. The CCL2-CCR2 axis is one of the major chemokine signaling pathways, and has various functions in tumor progression, such as increasing tumor cell proliferation and invasiveness, and creating a tumor microenvironment through increased angiogenesis and recruitment of immunosuppressive cells. This review discusses the roles of the CCL2-CCR2 axis and the tumor microenvironment in cancer progression and their future roles in cancer therapy.

Postoperative elevation in the plasma CCL2 level is a predictive biomarker of colorectal cancer recurrence

PURPOSE

There is currently no adequate biomarker for predicting colorectal cancer (CRC) recurrence. Chemokine (C-C motif) ligand 2 (CCL2) induces macrophages and fibroblasts to occupy metastatic niches in distant organs. The purpose of this study was to examine CCL2 as a potential predictive biomarker for CRC recurrence.

METHODS

Plasma samples (n = 402) were collected from 80 stage II/III/IV CRC cases and the relationship between CCL2 profiles and recurrence was investigated. The tumor immune response genes associated with CCL2 mRNA expression in a subgroup of 8 stage I/II CRC cases with 12 recurrent sites and The Cancer Genome Atlas database were also analyzed retrospectively.

RESULTS

Sixteen stage II/III/IV postoperative recurrent CRC cases experienced a significant increase in plasma CCL2 levels 6 months after surgery and continuously increased even after R0-1 resection. The 6-month postoperative CCL2 levels in recurrent cases of ≥ 1 year were significantly higher than in non-recurrent cases and recurrent cases of < 1 year. The CCL2 level in the primary tumor cases significantly correlated with the cytolytic activity, thus indicating a tumor immune response from the CD163-expressing macrophages.

CONCLUSION

Plasma CCL2 was found to be a predictive biomarker of postoperative CRC recurrence. CCL2 in metastatic sites derives from metastatic niches that surpass the host immune response.

Ovarian Cancer-Associated Mesothelial Cells: Transdifferentiation to Minions of Cancer and Orchestrate Developing Peritoneal Dissemination

Ovarian cancer has one of the poorest prognoses among carcinomas. Advanced ovarian cancer often develops ascites and peritoneal dissemination, which is one of the poor prognostic factors. From the perspective of the "seed and soil" hypothesis, the intra-abdominal environment is like the soil for the growth of ovarian cancer (OvCa) and mesothelial cells (MCs) line the top layer of this soil. In recent years, various functions of MCs have been reported, including supporting cancer in the OvCa microenvironment. We refer to OvCa-associated MCs (OCAMs) as MCs that are stimulated by OvCa and contribute to its progression. OCAMs promote OvCa cell adhesion to the peritoneum, invasion, and metastasis. Elucidation of these functions may lead to the identification of novel therapeutic targets that can delay OvCa progression, which is difficult to cure.

Effects of Gentiopicroside on Oxidative Stress and Apoptosis in Gastric Cancer Cells

Gastric cancer (GC) cells were sorted into six groups: NC, different concentrations of gentiopi-croside, pcDNA-NC, pcDNA-Nrf2, pcDNA-NC + gentiopicroside, and pcDNA-Nrf2 + gentiopicroside. The detection and comparison of cell survival and apoptosis showed that the activity of GC cells decreased and the apoptosis rate increased after gentiopicroside treatment. Western blot detection was performed to determine the expression levels of proliferating cell nuclear antigen (PCNA), B-cell leukemia/lymphoma-2 (Bcl-2)-associated X protein (Bax), Bcl-2, Kelch-like epichlorohydrin-associated protein 1 (Keap1), nuclear factor erythroid 2-related factor 2 (Nrf2), and antioxidant response element (ARE). Kits were used to determine the malondialdehyde (MDA) content, superoxide dismutase (SOD) activity, and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity. The MDA content, NADPH oxidase activity, and Keap1 and Bax expression levels increased, and the SOD activity and Bcl-2, PCNA, Nrf2, and ARE expression levels decreased. Nrf2 overexpression increased the cell activity, SOD activity, and Nrf2, ARE, PCNA, and Bcl-2 expression levels and reduced the apoptosis rate, MDA content, NADPH oxidase activity, and Bax and Keap1 expression levels. At the same time, Nrf2 overexpression reversed the effects of gentiopicroside on oxidative stress and apoptosis of GC cells. These results suggest that gentiopicroside probably promotes oxidative stress and apoptosis of GC cells by inhibiting the Keap1/Nrf2/ARE signaling pathway.

GINS2 affects cell proliferation, apoptosis, migration and invasion in thyroid cancer via regulating MAPK signaling pathway

Globally, thyroid cancer (TC) is considered to be the commonest endocrine malignancy. GINS complex subunit 2 (GINS2) belongs to the GINS complex family and is associated with cellular migration, invasion and growth. The present study aimed to investigate the underlying mechanisms of GINS2 on cell viability, migration and invasion in TC cells. By using MTT, wound healing and Transwell assays, the cell viability, migration and invasion were determined. Apoptosis was examined by immunofluorescence. Western blotting was used to detect protein expression levels. In the present study, biological function analysis demonstrated that GINS2 interference attenuated cell viability, migration and invasion in TC cell lines (K1 and SW579). It was discovered that, compared with the control group, GINS2 silencing induced apoptosis in TC cells. Additionally, GINS2 interference inhibited key proteins in the MAPK signaling pathway, including JNK, ERK and p38. According to these comparative experiments, GINS2 was considered to act a pivotal part in cell viability, migration and invasion of TC by regulating the MAPK signaling pathway and might be a potential therapeutic target for treating TC.

Fibroblast activation protein-α-adaptive micelles deliver anti-cancer drugs and reprogram stroma fibrosis

Cancer-associated fibroblasts (CAFs) are the majority cell population of tumor stroma, and they not only play important roles in tumor growth and metastasis, but they also form a protective physical barrier for cancer cells. Herein, we designed a fibroblast activation protein-α (FAP-α)-adaptive polymeric micelle based on hyaluronic acid and curcumin conjugates. The polymeric micelle is composed of a CD44-targeting shell and a FAP-α-cleavable polyethylene glycol (PEG) coating. When FAP-α is encountered on the surface of CAFs in the tumor microenvironment, the PEG layer is released, hyaluronic acid is recovered on the surface of nanoparticles, and the nanoparticles effectively inhibit the growth of tumor cells and CAFs through CD44-mediated endocytosis. The FAP-α-adaptive polymeric micelle exhibited potent anti-cancer efficacy by enhancing CAF apoptosis and reducing collagen in tumor tissues. Collectively, FAP-α-adaptive nanoparticles may be a promising method for antitumor anticancer treatments via reprogramming of stroma fibrosis.

Relationship between the Monocyte Chemo-attractant Protein-1 gene rs1024611 A>G Polymorphism and Cancer Susceptibility: A Meta-analysis Involving 14,617 Subjects

BACKGROUND

Inflammatory and inducible chemokines are the hallmarks of malignancy. Monocyte chemo-attractant protein-1 (MCP-1) is a crucial chemokine implicated in infection and inflammation. Methods: We performed an updated meta-analysis of thirty independent case-control studies with 6,777 cancer cases and 7,840 controls to determine if the MCP-1 gene rs1024611 A > G variant is associated with the risk of cancer. Results: The G allele carriers of rs1024611 in the MCP-1 gene might have a null association with cancer risk in overall comparison. In a subgroup analysis by ethnicity, we identified a marked association between the MCP-1 G allele rs1024611 polymorphism and cancer risk in the Caucasian populations (GG vs. AA: OR = 1.72, 95% CI, 1.12-2.64, P = .013, and GG vs. AG/AA: OR = 1.82, 95% CI, 1.19-2.78, P = .006). The potential bias in literature selection was witnessed in this meta-analysis (G vs. A: P _Begg's =  0.187, P_Egger's =  0.049; and GG/GA vs. AA: P _Begg's =  0.069, P_Egger's =  0.024). The adjusted ORs and CIs of the nonparametric "trim-and-fill" method demonstrated the reliability of these findings. The outcome of heterogeneity analysis indicated that heterogeneity might be due to small sample sizes (<1000 subjects), cancer types (bladder cancer, other cancers), ethnicity (Asians), and population-based studies. However, the sensitivity analysis validated the reliability of the findings. Conclusion: In conclusion, this updated meta-analysis showed that the G carrier of the MCP-1 gene rs1024611 is associated with susceptibility to cancer in Caucasian.

Establishment and Evaluation of a 6-Gene Survival Risk Assessment Model Related to Lung Adenocarcinoma Microenvironment

Objective

A survival risk assessment model associated with a lung adenocarcinoma (LUAD) microenvironment was established and evaluated to identify effective independent prognostic factors for LUAD.

Methods

The public data were downloaded from the TCGA database, and ESTIMATE prediction software was used to score immune cells and stromal cells for tumor purity prediction. The samples were divided into the high-score group and the low-score group by the median value of the immune score (or stromal score). The Wilcoxon test was used for differential analysis. GO and KEGG enrichment analysis of differentially expressed genes (DEGs) was performed using “clusterProfiler” of R package. Meanwhile, univariate and multivariate regression analysis was performed on DEGs to construct a multivariate Cox risk regression model with variable gene expression levels as independent prognostic factors affecting a tumor microenvironment (TME) and tumor immunity.

Results

This study found that LUAD patients with high immune cell (stromal cell) infiltration had better prognosis and were in earlier staging. Functional enrichment analysis revealed that most DEGs were related to the proliferation and activation of immune cells or stromal cells. A survival prediction model composed of 6 TME-related genes (CLEC17A, TAGAP, ABCC8, BCAN, FLT3, and CCR2) was established, and finally, the 6 feature genes closely related to the prognosis of LUAD were proved. The AUC value of the ROC curve in this model was 0.7, indicating that the model was reliable.

Conclusion

Six genes related to the LUAD microenvironment have a predictive prognostic value in LUAD.

Chemokines and their Receptors: Multifaceted Roles in Cancer Progression and Potential Value as Cancer Prognostic Markers

Chemokines are chemotactic cytokines that mediate immune cell chemotaxis and lymphoid tissue development. Recent advances have indicated that chemokines and their cognate receptors play critical roles in cancer-related inflammation and cancer progression. On the basis of these findings, the chemokine system has become a new potential drug target for cancer immunotherapy. In this review, we summarize the essential roles of the complex network of chemokines and their receptors in cancer progression. Furthermore, we discuss the potential value of the chemokine system as a cancer prognostic marker. The chemokine system regulates the infiltration of immune cells into the tumor microenvironment, which induces both pro- and anti-immunity and promotes or suppresses tumor growth and proliferation, angiogenesis, and metastasis. Increasing evidence indicates the promising prognostic value of the chemokine system in cancer patients. While CCL2, CXCL10, and CX3CL1/CX3CR1 can serve as favorable or unfavorable prognostic factors depending on the cancer types, CCL14 and XCL1 possess good prognostic value. Other chemokines such as CXCL1, CXCL8, and CXCL12 are poor prognostic markers. Despite vast advances in our understanding of the complex nature of the chemokine system in tumor biology, knowledge about the multifaceted roles of the chemokine system in different types of cancers is still limited. Further studies are necessary to decipher distinct roles within the chemokine system in terms of cancer progression and to validate their potential value in cancer prognosis.