Curcumin combined with FAPαc vaccine elicits effective antitumor response by targeting indolamine-2,3-dioxygenase and inhibiting EMT induced by TNF-α in melanoma

Curcumin modulates purinergic signaling and inflammatory response in cutaneous metastatic melanoma cells

Cutaneous melanoma (CM) poses a therapeutic challenge due to its aggressive nature and often limited response to conventional treatments. Exploring novel therapeutic targets is essential, and natural compounds have emerged as potential candidates. This study aimed to elucidate the impact of curcumin, a natural compound known for its anti-inflammatory, antioxidant, and anti-tumor properties, on metastatic melanoma cells, focusing on the purinergic system and immune responses. Human melanoma cell line SK-Mel-28 were exposed to different curcumin concentrations for either 6 or 24 h, after which we assessed components related to the purinergic system and the inflammatory cascade. Using RT-qPCR, we assessed the gene expression of CD39 and CD73 ectonucleotidases, as well as adenosine deaminase (ADA). Curcumin effectively downregulated CD39, CD73, and ADA gene expression. Flow cytometry analysis revealed that curcumin significantly reduced CD39 and CD73 protein expression at specific concentrations. Moreover, the A2A receptor's protein expression decreased across all concentrations. Enzymatic activity assays demonstrated that curcumin modulated CD39, CD73, and ADA activities, with effects dependent on concentration and duration of treatment. Extracellular ATP levels increased after 24 h of curcumin treatment, emphasizing its role in modulating hydrolytic activity. Curcumin also displayed anti-inflammatory properties by reducing NLRP3 gene expression and impacting the levels of key inflammatory cytokines. In conclusion, this study unveils the potential of curcumin as a promising adjuvant in CM treatment. Curcumin modulates the expression and activity of crucial components of the purinergic system and exhibits anti-inflammatory effects, indicating its potential therapeutic role in combating CM. These findings underscore curcumin's promise and warrant further investigation in preclinical and clinical settings for melanoma management.

Targeting fibroblast activation protein (FAP): advances in CAR-T cell, antibody, and vaccine in cancer immunotherapy

Fibroblast activation protein (FAP) is a serine protease with dual enzymatic activities overexpressed in cancer-associated fibroblasts (CAFs) in several tumor types, while its expression in healthy adult tissues is scarce. FAP overexpression on CAFs is associated with poor prognosis and plays an important role in tumor development, progression, and invasion. Therefore, FAP is considered a robust therapeutic target for cancer therapy. Here, we try to review and highlight the recent advances in immunotherapies for FAP targeting including the anti-FAP antibodies and immunoconjugates, FAP chimeric antigen receptor (CAR)-T cell, and various FAP vaccines in a preclinical and clinical setting. Subsequently, a discussion on the challenges and prospects associated with the development and translation of effective and safe therapies for targeting and depletion of FAP is provided. We proposed that new CAR-T cell engineering strategies and nanotechnology-based systems as well as advanced functional biomaterials can be used to improve the efficiency and safety of CAR-T cells and vaccines against FAP for more personalized immunotherapy. This review emphasizes the immune targeting of FAP as an emerging stromal candidate and one of the crucial elements in immunotherapy and shows the potential for improvement of current cancer therapy. A summary of different immunotherapy approaches to target fibroblast activation protein (FAP) for cancer therapy.

Mechanism of epithelial-mesenchymal transition in cancer and its regulation by natural compounds

Epithelial-mesenchymal transition (EMT) is a complex process with a primordial role in cellular transformation whereby an epithelial cell transforms and acquires a mesenchymal phenotype. This transformation plays a pivotal role in tumor progression and self-renewal, and exacerbates resistance to apoptosis and chemotherapy. EMT can be initiated and promoted by deregulated oncogenic signaling pathways, hypoxia, and cells in the tumor microenvironment, resulting in a loss-of-epithelial cell polarity, cell-cell adhesion, and enhanced invasive/migratory properties. Numerous transcriptional regulators, such as Snail, Slug, Twist, and ZEB1/ZEB2 induce EMT through the downregulation of epithelial markers and gain-of-expression of the mesenchymal markers. Additionally, signaling cascades such as Wnt/β-catenin, Notch, Sonic hedgehog, nuclear factor kappa B, receptor tyrosine kinases, PI3K/AKT/mTOR, Hippo, and transforming growth factor-β pathways regulate EMT whereas they are often deregulated in cancers leading to aberrant EMT. Furthermore, noncoding RNAs, tumor-derived exosomes, and epigenetic alterations are also involved in the modulation of EMT. Therefore, the regulation of EMT is a vital strategy to control the aggressive metastatic characteristics of tumor cells. Despite the vast amount of preclinical data on EMT in cancer progression, there is a lack of clinical translation at the therapeutic level. In this review, we have discussed thoroughly the role of the aforementioned transcription factors, noncoding RNAs (microRNAs, long noncoding RNA, circular RNA), signaling pathways, epigenetic modifications, and tumor-derived exosomes in the regulation of EMT in cancers. We have also emphasized the contribution of EMT to drug resistance and possible therapeutic interventions using plant-derived natural products, their semi-synthetic derivatives, and nano-formulations that are described as promising EMT blockers.

SNCA inhibits epithelial-mesenchymal transition and correlates to favorable prognosis of breast cancer

Alpha-synuclein (SNCA) is a pathological hallmark of Parkinson's disease, known to be involved in cancer occurrence and development; however, its specific effects in breast cancer remain unknown. Data from 150 patients with breast cancer were retrieved from tissue microarray and analyzed for SNCA protein level using immunohistochemistry. Functional enrichment analysis was performed to investigate the potential role of SNCA in breast cancer. SNCA-mediated inhibition of epithelial-mesenchymal transition (EMT) was confirmed with western blotting. The effects of SNCA on invasion and migration were evaluated using transwell and wound-healing experiments. Furthermore, the potential influence of SNCA expression level on drug sensitivity and tumor infiltration by immune cells was analyzed using the public databases. SNCA is lowly expressed in breast cancer tissues. Besides, in vitro and in vivo experiments, SNCA overexpression blocked EMT and metastasis, and the knockdown of SNCA resulted in the opposite effect. A mouse model of metastasis verified the restriction of metastatic ability in vivo. Further analysis revealed that SNCA enhances sensitivity to commonly used anti-breast tumor drugs and immune cell infiltration. SNCA blocks EMT and metastasis in breast cancer and its expression levels could be useful in predicting the chemosensitivity and evaluating the immune microenvironment in breast cancer.

Targeting cancer-associated fibroblasts: Challenges, opportunities and future directions

Cancer-associated fibroblasts (CAFs) are a common cell in the tumour microenvironment with diverse tumour-promoting functions. Their presence in tumours is commonly associated with poor prognosis making them attractive therapeutic targets, particularly in the context of immunotherapy where CAFs have been shown to promote resistance to checkpoint blockade. Previous attempts to inhibit CAFs clinically have not been successful, however, in part due to a lack of understanding of CAF heterogeneity and function, with some fibroblast populations potentially being tumour suppressive. Recent single-cell transcriptomic studies have advanced our understanding of fibroblast phenotypes in normal tissues and cancers, allowing for a more precise characterisation of CAF subsets and providing opportunities to develop new therapies. Here we review recent advances in the field, focusing on the evolving area of therapeutic CAF targeting.

Epitope-based minigene vaccine targeting fibroblast activation protein α induces specific immune responses and anti-tumor effects in 4 T1 murine breast cancer model

Fibroblast activation protein (FAPα) is a tumor stromal antigen expressed by cancer-associated fibroblasts (CAFs) in more than 90 % of malignant epithelial carcinomas. FAPα-based immunotherapy has been reported and showed that FAPα-specific immune response can remold immune microenvironment and contribute to tumor regression. Many FAPα-based vaccines have been investigated in preclinical trials, which can elicit strong and durable cytolytic T lymphocytes (CTL) with good safety. However, epitope-based FAPα vaccines are rarely reported. To break tolerance against self-antigens, analogue epitopes with modified peptides at the anchor residues are typically used to improve epitope immunogenicity. To investigate the feasibility of a FAPα epitope-based vaccine for cancer immunotherapy in vivo, we conducted a preclinical study to identify a homologous CTL epitope of human and mouse FAPα and obtained its analogue epitope in BALB/c mice, and explored the anti-tumor activity of their minigene vaccines in 4 T1 tumor-bearing mice. By using in silico epitope prediction tools and immunogenicity assays, immunodominant epitope FAP.291 (YYFSWLTWV) and its analogue epitope FAP.291I9 (YYFSWLTWI) were identified. The FAP.291-based epitope minigene vaccine successfully stimulated CTLs targeting CAFs and exhibited anti-tumor activity in a 4 T1 murine breast cancer model. Furthermore, although the analogue epitope FAP.291I9 enhanced FAP.291-specific immune responses, improvement of anti-tumor immunity effects was not observed. Check of immunosuppressive factors revealed that the high levels of IL-10, IL-13, myeloid-derived suppressor cells and iNOS induced by FAP.291I9 increased, which considered the main cause of the failure of the analogue epitope-based vaccine. Thus, we demonstrated for the first time that the FAP.291 minigene vaccine could induce mouse CTLs and also function as a tumor regression antigen, providing the basis for future studies of FAPα epitope-based vaccines. This study may also be valuable for further improvement of the immunogenicity of analogue epitope vaccines.

Research progress on the role of fibroblast activation protein in diagnosis and treatment of cancer

Fibroblast activation protein (FAP) is a type II transmembrane protein, which is over-expressed in cancer-associated fibroblasts (CAFs). CAFs are tumor stromal cells that constitute a major component of cancer volume and are reportedly related to tumorigenesis, angiogenesis, metastasis, promotion of drug resistance and induction of tumor immunity. FAP is widely acknowledged as the signature protein of CAFs. At present, FAP inhibitors (FAPI) have achieved ideal results in tumor PET/computed tomography (CT) imaging. Theoretically, FAP-targeted drugs can inhibit tumor progression. Nonetheless, no satisfactory therapeutic effect has been observed so far, which has impeded their implementation in clinical practice. In this review, we describe the characteristics of FAP and its role in the occurrence and development of cancer. We also highlight the potential value of targeting FAP to improve current diagnostic and therapeutic approaches.

Targeting of the tumor microenvironment by curcumin

The tumor microenvironment (TME) is made up of several cells and molecules that affect the survival of cancer cells. Indeed, certain (immunosuppressive) cells which promote tumors can promote the growth of tumors by stimulating the proliferation of cancer cells and promoting angiogenesis. During tumor growth, antitumoral immunity includes natural killer cells and CD8+ T cells cannot overcome immunosuppressive responses and cancer cell proliferation. In order to achieve the appropriate therapeutic response, we must kill cancer cells and suppress the release of immunosuppressive molecules. The balance between anti-tumor immunity and immunosuppressive cells, such as regulatory T cells (Tregs), cancer-associated fibroblasts, tumor-associated macrophages, and myeloid-derived suppressor cells plays a key role in the suppression or promotion of cancer cells. Curcumin is a plant-derived agent that has shown interesting properties for cancer therapy. It has shown that not only directly inhibit the growth of cancer cells, but can also modulate the growth and activity of immunosuppressant and tumor-promoting cells. In this review, we explain how curcumin modulates interactions within TME in favor of tumor treatment. The potential modulating effects of curcumin on the responses of cancer cells to treatment modalities such as immunotherapy will also be discussed.

Crosstalk between cancer-associated fibroblasts and immune cells in the tumor microenvironment: new findings and future perspectives

Cancer-associated fibroblasts (CAFs), a stromal cell population with cell-of-origin, phenotypic and functional heterogeneity, are the most essential components of the tumor microenvironment (TME). Through multiple pathways, activated CAFs can promote tumor growth, angiogenesis, invasion and metastasis, along with extracellular matrix (ECM) remodeling and even chemoresistance. Numerous previous studies have confirmed the critical role of the interaction between CAFs and tumor cells in tumorigenesis and development. However, recently, the mutual effects of CAFs and the tumor immune microenvironment (TIME) have been identified as another key factor in promoting tumor progression. The TIME mainly consists of distinct immune cell populations in tumor islets and is highly associated with the antitumor immunological state in the TME. CAFs interact with tumor-infiltrating immune cells as well as other immune components within the TIME via the secretion of various cytokines, growth factors, chemokines, exosomes and other effector molecules, consequently shaping an immunosuppressive TME that enables cancer cells to evade surveillance of the immune system. In-depth studies of CAFs and immune microenvironment interactions, particularly the complicated mechanisms connecting CAFs with immune cells, might provide novel strategies for subsequent targeted immunotherapies. Herein, we shed light on recent advances regarding the direct and indirect crosstalk between CAFs and infiltrating immune cells and further summarize the possible immunoinhibitory mechanisms induced by CAFs in the TME. In addition, we present current related CAF-targeting immunotherapies and briefly describe some future perspectives on CAF research in the end.

TGF-β1-activated cancer-associated fibroblasts promote breast cancer invasion, metastasis and epithelial-mesenchymal transition by autophagy or overexpression of FAP-α

Cancer-associated fibroblasts (CAFs) play an important role in the initiation, metastasis, and invasion of breast cancer. However, whether autophagy acts as a tumor promotion mechanism by inducing epithelial-mesenchymal transition (EMT) is still controversial and remains undefined at the mechanistic levels. In this study, we investigated whether autophagy or FAP-α is required for the invasion, pulmonary metastasis and EMT of breast cancer cells and underlying mechanism. We employed an in vitro model of NIH3T3 fibroblasts treated with H₂O₂ and confirmed that TGF-β1 could convert fibroblasts into CAFs through autophagy under oxidative stress in the tumor microenvironment. Modulation of autophagy by rapamycin, 3-methyladenine or ATG-5 knockdown regulated the expression of CAFs markers, suggesting a role of autophagy in the tumor promotion mechanism of TGF-β1-induced CAFs activation. Furthermore, we established an indirect co-culture model and a mixed xenograft as a corresponding in vivo model. We demonstrated that TGF-β1-activated CAFs promote tumor invasion, pulmonary metastasis and EMT, which act through autophagy and overexpression of FAP-α in both models, while autophagy inhibitor 3-methyladenine blocked these effects induced by TGF-β1-activated CAFs. Moreover, the co-localization of LC3β and EMT marker vimentin in mixed xenograft also revealed that TGF-β1-activated CAFs promote tumor growth, pulmonary metastasis, and EMT program partly through autophagy. In addition, knockdown of FAP-α resulted in reversed EMT and abolished tumor invasion and pulmonary metastasis induced by TGF-β1-activated CAFs. Taken together, we conclude that both autophagy and FAP-α are required for breast cancer cell invasion and metastasis. Targeting autophagy or FAP-α rather than both can serve as a potential approach to improve the prognosis for human breast cancer.

Hyperglycemia and Chemoresistance in Breast Cancer: From Cellular Mechanisms to Treatment Response

Female breast cancer is a complex, multifactorial disease. Studies have shown that hyperglycemia is one of the most important contributing factors to increasing the risk of breast cancer that also has a major impact on the efficacy of chemotherapy. At the cellular level, hyperglycemia can promote the proliferation, invasion, and migration of breast cancer cells and can also induce anti-apoptotic responses to enhance the chemoresistance of tumors via abnormal glucose metabolism. In this article, we focus on the latest progress in defining the mechanisms of chemotherapy resistance in hyperglycemic patients including the abnormal behaviors of cancer cells in the hyperglycemic microenvironment and the impact of abnormal glucose metabolism on key signaling pathways. To better understand the advantages and challenges of breast cancer treatments, we explore the causes of drug resistance in hyperglycemic patients that may help to better inform the development of effective treatments.

Reversal of Epithelial-Mesenchymal Transition by Natural Anti-Inflammatory and Pro-Resolving Lipids

Epithelial mesenchymal transition (EMT) is a key process in the progression of malignant cancer. Therefore, blocking the EMT can be a critical fast track for the development of anticancer drugs. In this paper, we update recent research output of EMT and we explore suppression of EMT by natural anti-inflammatory compounds and pro-resolving lipids.

The E-Cadherin and N-Cadherin Switch in Epithelial-to-Mesenchymal Transition: Signaling, Therapeutic Implications, and Challenges

Epithelial-to-Mesenchymal Transition (EMT) has been shown to be crucial in tumorigenesis where the EMT program enhances metastasis, chemoresistance and tumor stemness. Due to its emerging role as a pivotal driver of tumorigenesis, targeting EMT is of great therapeutic interest in counteracting metastasis and chemoresistance in cancer patients. The hallmark of EMT is the upregulation of N-cadherin followed by the downregulation of E-cadherin, and this process is regulated by a complex network of signaling pathways and transcription factors. In this review, we summarized the recent understanding of the roles of E- and N-cadherins in cancer invasion and metastasis as well as the crosstalk with other signaling pathways involved in EMT. We also highlighted a few natural compounds with potential anti-EMT property and outlined the future directions in the development of novel intervention in human cancer treatments. We have reviewed 287 published papers related to this topic and identified some of the challenges faced in translating the discovery work from bench to bedside.

Effects of hyperglycemia on the progression of tumor diseases

Malignant tumors are often multifactorial. Epidemiological studies have shown that hyperglycemia raises the prevalence and mortality of certain malignancies, like breast, liver, bladder, pancreatic, colorectal, endometrial cancers. Hyperglycemia can promote the proliferation, invasion and migration, induce the apoptotic resistance and enhance the chemoresistance of tumor cells. This review focuses on the new findings in the relationship between hyperglycemia and tumor development.

Unraveling the molecular mechanisms and the potential chemopreventive/therapeutic properties of natural compounds in melanoma

Melanoma is the most fatal form of skin cancer. Current therapeutic approaches include surgical resection, chemotherapy, targeted therapy and immunotherapy. However, these treatment strategies are associated with development of drug resistance and severe side effects. In recent years, natural compounds have also been extensively studied for their anti-melanoma effects, including tumor growth inhibition, apoptosis induction, angiogenesis and metastasis suppression and cancer stem cell elimination. Moreover, a considerable number of studies reported the synergistic activity of phytochemicals and standard anti-melanoma agents, as well as the enhanced effectiveness of their synthetic derivatives and novel formulations. However, clinical data confirming these promising effects in patients are still scanty. This review emphasizes the anti-tumor mechanisms and potential application of the most studied natural products for melanoma prevention and treatment.

Curcumin: a potent agent to reverse epithelial-to-mesenchymal transition

BACKGROUND

Epithelial-to-mesenchymal transition (EMT) is involved in tumor progression, invasion, migration and metastasis. EMT is a process by which polarized epithelial cells acquire motile mesothelial phenotypic features. This process is initiated by disassembly of cell-cell contacts through the loss of epithelial markers and replacement of these markers by mesenchymal markers. Reconstruction of the cytoskeleton and degradation of the tumor basement membrane ensures the spread of invasive malignant tumor cells to distant locations. Accumulating evidence indicates that curcumin, as a well-known phytochemical, can inhibit EMT/metastasis through various mechanisms and pathways in human tumors.

CONCLUSIONS

In this review, we summarize the mechanisms by which curcumin may affect EMT in cells under pathological conditions to understand its potential as a novel anti-tumor agent. Curcumin can exert chemo-preventive effects by inhibition and reversal of the EMT process through both TGF-β-dependent (e.g. in hepatoma and retinal pigment epithelial cancer) and -independent (e.g. in oral cancer, colorectal cancer, pancreatic cancer, hepatocellular carcinoma, breast cancer, melanoma, prostate cancer, bladder cancer, thyroid cancer and lung cancer) pathways. Curcumin can also mitigate chemoresistance through EMT suppression and promotion of the antiproliferative effects of conventional chemotherapeutics. Therefore, curcumin has the potential to be used as a novel adjunctive agent to prevent tumor metastasis, which may at least partly be attributed to its hampering of the EMT process.

Anticancer potential of naturally occurring immunoepigenetic modulators: A promising avenue?

The immune system represents the major primary defense line against carcinogenesis and acts by identifying and eradicating nascent transformed cells. A growing body of evidence is indicating that aberrant epigenetic reprogramming plays a key role in tumor immune escape through: 1) impaired efficient recognition of neoplastic cells by the immune system, resulting from a downregulation or loss of the expression of tumor-associated antigens, human leukocyte antigens, antigen processing and presenting machinery, and costimulatory molecule genes; 2) aberrant expression of immune checkpoint proteins and their ligands; and 3) modification of cytokine profiles and tumor-associated immune cell populations toward an immunosuppressive state in the tumor microenvironment. Consistent with the inherent reversibility of epigenetic alterations, epigenetic drugs, including DNA methyltransferase and histone deacetylase inhibitors, have the unique potential to favorably modify the tumor microenvironment, restore tumor recognition and stimulate an antitumor immune response. The objective of this review is to highlight selected, naturally occurring epigenetic modulators, namely, butyrate, curcumin, (-)-epigallocatechin-3-gallate, resveratrol, romidepsin, and trichostatin A, with a special focus on their antitumor immune properties.

Chemopreventive and therapeutic potential of curcumin in esophageal cancer: Current and future status

Esophageal cancer is a common malignant tumor with an increasing trend during the past three decades. Currently, esophagectomy, often in combination with neoadjuvant chemo- and radiotherapy, is the cornerstone of curative treatment for esophageal cancer. However, esophagostomy is related to significant risks of perioperative mortality and morbidity, as well as lengthy recovery. Moreover, the adjuvant therapies including chemotherapy and radiotherapy are associated with numerous side effects, limiting compliance and outcome. The dietary agent curcumin has been extensively studied over the past few decades and is known to have many biological activities especially in regard to the prevention and potential treatment of cancer. This review summarizes the chemo-preventive and chemotherapeutic potential of curcumin in esophageal cancer in both preclinical and clinical settings.

Pro-tumorigenic roles of fibroblast activation protein in cancer: back to the basics

Fibroblast activation protein (FAP) is a cell-surface serine protease that acts on various hormones and extracellular matrix components. FAP is highly upregulated in a wide variety of cancers, and is often used as a marker for pro-tumorigenic stroma. It has also been proposed as a molecular target of cancer therapies, and, especially in recent years, a great deal of research has gone into design and testing of diverse FAP-targeted treatments. Yet despite this growing field of research, our knowledge of FAP's basic biology and functional roles in various cancers has lagged behind its use as a tumor-stromal marker. In this review, we summarize and analyze recent advances in understanding the functions of FAP in cancer, most notably its prognostic value in various tumor types, cellular effects on various cell types, and potential as a therapeutic target. We highlight outstanding questions in the field, the answers to which could shape preclinical and clinical studies of FAP.

Diabetes mellitus stimulates pancreatic cancer growth and epithelial-mesenchymal transition-mediated metastasis via a p38 MAPK pathway

Diabetes mellitus (DM) and its accompanying chronic inflammation promote tumor progression. p38 mitogen-activated protein kinase (MAPK) is an essential kinase for inflammation. The effects of p38 MAPK on epithelial-mesenchymal transition (EMT)-mediated diabetic pancreatic cancer metastasis remain unclear. Here, we demonstrate that p38 MAPK phosphorylation was significantly increased in pancreatic cancer cells treated with high glucose and in pancreatic tumors from diabetic animals. A p38 MAPK inhibitor significantly suppressed the proliferation and invasion of pancreatic cancer cells under high-glucose conditions. Moreover, p38 MAPK inhibition not only significantly decreased both the tumor volume monitored by magnetic resonance imaging and EMT-related metastasis but also increased the survival of diabetic mice bearing pancreatic tumors. Furthermore, the inflammation in diabetic animals bearing pancreatic tumors was also significantly lower after therapy. Collectively, our findings reveal that p38 MAPK inhibitors may provide a novel intervention strategy for diabetic pancreatic cancer treatment.

The application of the fibroblast activation protein α-targeted immunotherapy strategy

Cancer immunotherapy has primarily been focused on attacking tumor cells. However, given the close interaction between tumor cells and cancer-associated fibroblasts (CAFs) in the tumor microenvironment (TME), CAF-targeted strategies could also contribute to an integrated cancer immunotherapy. Fibroblast activation protein α (FAP α) is not detectible in normal tissues, but is overexpressed by CAFs and is the predominant component of the stroma in most types of cancer. FAP α has both dipeptidyl peptidase and endopeptidase activities, cleaving substrates at a post-proline bond. When all FAP α-expressing cells (stromal and cancerous) are destroyed, tumors rapidly die. Furthermore, a FAP α antibody, FAP α vaccine, and modified vaccine all inhibit tumor growth and prolong survival in mouse models, suggesting FAP α is an adaptive tumor-associated antigen. This review highlights the role of FAP α in tumor development, explores the relationship between FAP α and immune suppression in the TME, and discusses FAP α as a potential immunotherapeutic target.

p68 prompts the epithelial-mesenchymal transition in cervical cancer cells by transcriptionally activating the TGF-β1 signaling pathway

Overexpression of p68 has been reported in various types of cancer. However, little study has been conducted on the expression and role of p68 in cervical cancer. Therefore, the present study focuses on the role of p68 in cervical cancer cells, which may elucidate its potential mechanism of cervical cancer progression and shed light on the precision medical treatment of cervical cancer. Firstly, the expression of p68 was analyzed using reverse transcription-quantitative polymerase chain reaction and western blot analysis. The changes to cell morphology were observed using an inverted microscope (XDS-500D; Shanghai Caikon Optical Instrument Co., Ltd., Shanghai, China). Cell migration was determined using an in vitro scratch assay. The present study demonstrated that the mRNA and protein levels of p68 were significantly enhanced in cervical cancer CaSki, HeLa [human papillomavirus (HPV)-18-positive], SiHa (HPV-16-positive) and C-33A (HPV-negative) cell lines compared with the human keratinocyte HaCaT cell line. Overexpression of p68 induced an elongated and spindle-shaped morphology in CaSki cells. Upregulation of p68 increased the expression of α-smooth muscle actin, vimentin and fibronectin however, epithelial marker E-cadherin was significantly decreased. Furthermore, the in vitro scratch assay demonstrated that overexpression of p68 markedly enhanced CaSki cell migration capacity at 24 and 48 h. Knockdown of p68 partially reversed transforming growth factor-β1 (TGF-β1)-induced changes in epithelial-mesenchymal transition (EMT) markers and cell morphological changes. In summary, the present study demonstrated that p68 transcriptionally activated the expression of TGF-β1, thereby prompting EMT in cervical cancer cells.

Curcumin downregulates the expression of Snail via suppressing Smad2 pathway to inhibit TGF-β1-induced epithelial-mesenchymal transitions in hepatoma cells

Hepatocellular carcinoma (HCC) remains the third cause of cancer-related mortality. Resection and transplantation are the only curative treatments available but are greatly hampered by high recurrence rates and development of metastasis, the initiation of cancer metastasis requires migration and invasion of cells, which is enabled by epithelial-mesenchymal transitions (EMT). TGF-β1 is a secreted protein that performs many cellular functions, including the control of cell growth, cell proliferation, cell differentiation and apoptosis. TGF-β1 is known as a major inducer of EMT, and it was reported that TGF-β1 induced EMT via Smad-dependent and Smad-independent pathways. However, the extrinsic signals of TGF-β1 regulated the EMT in hepatoma cells remains to be elucidated, and searching drugs to inhibit TGF-β1 induced EMT may be considered to be a potentially effective therapeutic strategy in HCC. Fortunately, in this study, we found that curcumin inhibited TGF-β1-induced EMT in hepatoma cells. Furthermore, we demonstrated that curcumin inhibited TGF-β1-induced EMT via inhibiting Smad2 phosphorylation and nuclear translocation, then suppressing Smad2 combined with the promoter of Snail which inhibited the transcriptional expression of Snail. These findings suggesting curcumin could be a useful agent for antitumor therapy and also a promising drug combined with other strategies to preventing and treating HCC.

Curcumin reversed chronic tobacco smoke exposure induced urocystic EMT and acquisition of cancer stem cells properties via Wnt/β-catenin

Tobacco smoke (TS) is the most important single risk factor for bladder cancer. Epithelial–mesenchymal transition (EMT) is a transdifferentiation process, involved in the initiation of TS-related cancer. Cancer stem cells (CSCs) have an essential role in the progression of many tumors including TS-related cancer. However, the molecular mechanisms of TS exposure induced urocystic EMT and acquisition of CSCs properties remains undefined. Wnt/β-catenin pathway is critical for EMT and the maintenance of CSCs. The aim of our present study was to investigate the role of Wnt/β-catenin pathway in chronic TS exposure induced urocystic EMT, stemness acquisition and the preventive effect of curcumin. Long time TS exposure induced EMT changes and the levels of CSCs’ markers were significant upregulated. Furthermore, we demonstrated that Wnt/β-catenin pathway modulated TS-triggered EMT and stemness, as evidenced by the findings that TS elevated Wnt/β-catenin activation, and that TS-mediated EMT and stemness were attenuated by Wnt/β-catenin inhibition. Treatment of curcumin reversed TS-elicited activation of Wnt/β-catenin, EMT and CSCs properties. Collectively, these data indicated the regulatory role of Wnt/β-catenin in TS-triggered urocystic EMT, acquisition of CSCs properties and the chemopreventive effect of curcumin.

Targeting epithelial-mesenchymal plasticity in cancer: clinical and preclinical advances in therapy and monitoring

The concept of epithelial-mesenchymal plasticity (EMP), which describes the dynamic flux within the spectrum of phenotypic states that invasive carcinoma cells may reside, is being increasingly recognised for its role in cancer progression and therapy resistance. The myriad of events that are able to induce EMP, as well as the more recently characterised control loops, results in dynamic transitions of cancerous epithelial cells to more mesenchymal-like phenotypes through an epithelial-mesenchymal transition (EMT), as well as the reverse transition from mesenchymal phenotypes to an epithelial one. The significance of EMP, in its ability to drive local invasion, generate cancer stem cells and facilitate metastasis by the dissemination of circulating tumour cells (CTCs), highlights its importance as a targetable programme to combat cancer morbidity and mortality. The focus of this review is to consolidate the existing knowledge on the strategies currently in development to combat cancer progression via inhibition of specific facets of EMP. The prevalence of relapse due to therapy resistance and metastatic propensity that EMP endows should be considered when designing therapy regimes, and such therapies should synergise with existing chemotherapeutics to benefit efficacy. To further improve upon EMP-targeted therapies, it is imperative to devise monitoring strategies to assess the impact of such treatments on EMP-related phenomenon such as CTC burden, chemosensitivity/-resistance and micrometastasis in patients.

Curcumin inhibits bladder cancer progression via regulation of β-catenin expression

Bladder cancer has a considerable morbidity and mortality impact with particularly poor prognosis. Curcumin has been recently noticed as a polyphenolic compound separated from turmeric to regulate tumor progression. However, the precise molecular mechanism by which curcumin inhibits the invasion and metastasis of bladder cancer cells is not fully elucidated. In this study, we investigate the effect of curcumin on the bladder cancer as well as possible mechanisms of curcumin. The expression of β-catenin was detected by quantitative real-time polymerase chain reaction and immunohistochemical analysis in a series of bladder cancer tissues. In addition, bladder cancer cell lines T24 and 5637 cells were treated with different concentrations of curcumin. The cytotoxic effect of curcumin on cell proliferation of T24 and 5637 cells was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The migration and invasion capacity of T24 and 5637 cells were measured by transwell assay. The effects of curcumin on expression levels of β-catenin and epithelial-mesenchymal transition marker were determined by western blotting. The β-catenin expression was significantly upregulated in bladder cancer tissues when compared with corresponding peri-tumor tissues. Furthermore, curcumin inhibited the cell proliferation of T24 and 5637 cells, and curcumin reduced the migration and invasive ability of T24 and 5637 cells via regulating β-catenin expression and reversing epithelial-mesenchymal transition. Curcumin may be a new drug for bladder cancer.

[Tumor Associated Fibroblasts Promote PD-L1 Expression in Lung Cancer Cells]

背景与目的

肿瘤相关成纤维细胞（tumor-associated fibroblasts, TAF）是肿瘤微环境的重要组成部分，可抑制免疫细胞的功能。在肿瘤免疫中CD8⁺T细胞发挥重要的作用，T细胞膜表面程序性死亡因子1（programmed death factor 1, PD-1），与其配体PD-L1（programmed death factor ligand 1, PD-L1）结合对T细胞的激活起负调节作用。本研究旨在探讨TAF对肺癌细胞PD-L1表达的影响。

方法

我们以肺癌细胞株H1975、H520和TAF细胞进行Transwell非接触式共培养48 h的H1975、H520细胞为实验组，单独培养的H1975、H520细胞为对照组，两组培养条件一致。倒置显微镜计数实验组和对照组H1975、H520细胞数、流式细胞仪分别检测实验组和对照组肺癌细胞PD-L1的蛋白表达率、RT-PCR分别检测实验组和对照组肺癌细胞PD-L1 mRNA的表达。

结果

每100 μm²细胞计数，H1975细胞实验组为（46±21）个，对照组为（16±5）个（P < 0.05）；H520细胞实验组为（38±10）个，对照组为（12±5）个（P < 0.05）。PD-L1蛋白表达率，H1975细胞实验组为（20.93%±3.54%），对照组为（12.58%±2.52%）（P < 0.05）；H520细胞实验组（19.26%±3.04%），对照组为（11.60%±2.65%）（P < 0.05）。mRNA表达水平，H1975细胞实验组为（16.45±1.25）pg/mL，对照组为（7.78±1.27）pg/mL（P < 0.05）；H520细胞实验组为（15.38±2.02）pg/mL，对照组为（7.20±1.58）pg/mL（P < 0.05）。

结论

TAF促进肺癌细胞株H1975、H520的生长，增强细胞株PD-L1表达。

Bisdemethoxycurcumin in combination with α-PD-L1 antibody boosts immune response against bladder cancer

Curcumin was recently discovered to strengthen immune response through multiple mechanisms. Cytotoxic CD8⁺ T-cells play a critical role in modulating anticancer immune response, but is severely restricted by T-cell exhaustion. Bladder carcinomas express PD-L1 and can abrogate CD8⁺ T-cell response. Thus, we hypothesized that bisdemethoxycurcumin, a natural dimethoxy derivative of curcumin, may provide a favorable environment for T-cell response against bladder cancer when used in combination with α-PD-L1 antibody. Immunocompetent C56BL/6 mouse models bearing subcutaneous or lung metastasized MB79 bladder cancer were established to validate this conjecture. We found that bisdemethoxycurcumin significantly increased intratumoral CD8⁺ T-cell infiltration, elevated the level of IFN-γ in the blood, and decreased the number of intratumoral myeloid-derived suppressor cells. Furthermore, α-PD-L1 antibody protected these amplified CD8⁺ T-cells from exhaustion, and therefore facilitated the secretion of IFN-γ, granzyme B, and perforin through these CD8⁺ T-cells. As a result, this combination treatment strategy significantly prolonged survival of intraperitoneal metastasized bladder cancer bearing mice, suggesting that bisdemethoxycurcumin in combination with α-PD-L1 antibody may be promising for bladder cancer patients.

Antitumor effects of curcumin in human bladder cancer in vitro

Bladder cancer is one of the major causes of cancer-associated mortality, with a high incidence. Curcumin, a polyphenol compound extracted from turmeric, has been identified to regulate tumor progression. However, the therapeutic effect of curcumin in human bladder cancer has not yet been determined. In the present study, the effects of curcumin on cell growth, apoptosis and migration of bladder cancer cell lines were evaluated using an MTT assay, a Transwell assay and flow cytometry, and the associated mechanisms were investigated using western blot analysis. Curcumin was identified to decrease the growth of T24 and 5637 cells in a dose- and time-dependent manner. The present study confirmed that curcumin is able to inhibit cell migration and promote apoptosis of bladder cancer through suppression of matrix metalloproteinase signaling pathways in vitro. The anticancer effects of curcumin on bladder cancer cells may benefit clinical practice in the future.

Potential therapeutic targets of epithelial-mesenchymal transition in melanoma

Melanoma is a cutaneous neoplastic growth of melanocytes with great potential to invade and metastasize, especially when not treated early and effectively. Epithelial-mesenchymal transition (EMT) is the process by which melanocytes lose their epithelial characteristics and acquire mesenchymal phenotypes. Mesenchymal protein expression increases the motility, invasiveness, and metastatic potential of melanoma. Many pathways play a role in promotion of mesenchymal protein expression including RAS/RAF/MEK/ERK, PI3K/AKT/mTOR, Wnt/β-catenin, and several others. Downstream effectors of these pathways induce expression of EMT transcription factors including Snail, Slug, Twist, and Zeb that promote repression of epithelial and induction of mesenchymal character. Emerging research has demonstrated that a variety of small molecule inhibitors as well as phytochemicals can influence the progression of EMT and may even reverse the process, inducing re-expression of epithelial markers. Phytochemicals are of particular interest as supplementary treatment options because of their relatively low toxicities and anti-EMT properties. Modulation of EMT signaling pathways using synthetic small molecules and phytochemicals is a potential therapeutic strategy for reducing the aggressive progression of metastatic melanoma. In this review, we discuss the emerging pathways and transcription factor targets that regulate EMT and evaluate potential synthetic small molecules and naturally occurring compounds that may reduce metastatic melanoma progression.

Use of Polyphenolic Compounds in Dermatologic Oncology

Polyphenols are a widely used class of compounds in dermatology. While phenol itself, the most basic member of the phenol family, is chemically synthesized, most polyphenolic compounds are found in plants and form part of their defense mechanism against decomposition. Polyphenolic compounds, which include phenolic acids, flavonoids, stilbenes, and lignans, play an integral role in preventing the attack on plants by bacteria and fungi, as well as serving as cross-links in plant polymers. There is also mounting evidence that polyphenolic compounds play an important role in human health as well. One of the most important benefits, which puts them in the spotlight of current studies, is their antitumor profile. Some of these polyphenolic compounds have already presented promising results in either in vitro or in vivo studies for non-melanoma skin cancer and melanoma. These compounds act on several biomolecular pathways including cell division cycle arrest, autophagy, and apoptosis. Indeed, such natural compounds may be of potential for both preventive and therapeutic fields of cancer. This review evaluates the existing scientific literature in order to provide support for new research opportunities using polyphenolic compounds in oncodermatology.

Curcumin: A new candidate for melanoma therapy?

Melanoma remains among the most lethal cancers and, in spite of great attempts that have been made to increase the life span of patients with metastatic disease, durable and complete remissions are rare. Plants and plant extracts have long been used to treat a variety of human conditions; however, in many cases, effective doses of herbal remedies are associated with serious adverse effects. Curcumin is a natural polyphenol that shows a variety of pharmacological activities including anti-cancer effects, and only minimal adverse effects have been reported for this phytochemical. The anti-cancer effects of curcumin are the result of its anti-angiogenic, pro-apoptotic and immunomodulatory properties. At the molecular and cellular level, curcumin can blunt epithelial-to-mesenchymal transition and affect many targets that are involved in melanoma initiation and progression (e.g., BCl2, MAPKS, p21 and some microRNAs). However, curcumin has a low oral bioavailability that may limit its maximal benefits. The emergence of tailored formulations of curcumin and new delivery systems such as nanoparticles, liposomes, micelles and phospholipid complexes has led to the enhancement of curcumin bioavailability. Although in vitro and in vivo studies have demonstrated that curcumin and its analogues can be used as novel therapeutic agents in melanoma, curcumin has not yet been tested against melanoma in clinical practice. In this review, we summarized reported anti-melanoma effects of curcumin as well as studies on new curcumin formulations and delivery systems that show increased bioavailability. Such tailored delivery systems could pave the way for enhancement of the anti-melanoma effects of curcumin.

Curcumin inhibits tumor epithelial‑mesenchymal transition by downregulating the Wnt signaling pathway and upregulating NKD2 expression in colon cancer cells

Tumor invasion and metastasis are closely associated with epithelial-mesenchymal transition (EMT). EMT refers to epithelial cells under physiological and pathological conditions that are specific to mesenchymal transition. Curcumin inhibits EMT progression via Wnt signaling. The Wnt signaling pathway is a conservative EMT-related signaling pathway that is involved in the development of various tumors. In the present study, MTS assays were employed to analyze the proliferation of curcumin-treated cells. Naked cuticle homolog 2 (NKD2), chemokine receptor 4 (CXCR4) and antibodies associated with EMT were examined in SW620 colorectal cancer cell lines using western blot analysis and real-time qPCR. NKD2 small-interfering RNA (siRNA) and CXCR4 expression plasmid was synthesized and transfected into the colorectal cancer cell lines, and NKD2 and CXCR4 expression levels were detected. The results showed that curcumin significantly inhibited the proliferation of colorectal cancer cells and upregulated the expression of NKD2 in SW620 colorectal cancer cells and in the xenograft, resulting in the downregulation of key markers in the Wnt signaling. In addition, the progression of ETM was inhibited due to the overexpression of E-cadherin as well as the downregulation of vimentin. Curcumin also inhibited tumor metastasis by downregulating the expression of CXCR4 significantly. The results suggested involvement of the NKD2-Wnt-CXCR4 signaling pathway in colorectal cancer cells. In addition, curcumin is inhibit this signaling and the development of colorectal cancer.

Bitargeted microemulsions based on coix seed ingredients for enhanced hepatic tumor delivery and synergistic therapy

A hepatic tumor bitargeted microemulsions drug delivery system using coix seed oil and coix seed polysaccharide (CP) acting as anticancer components, as well as functional excipients, was developed for enhanced tumor-specific accumulation by CP-mediated enhancement on passive tumor targeting and modification of galactose stearate (tumor-targeted ligand). In the physicochemical characteristics studies, galactose stearate-modified coix seed multicomponent microemulsions containing 30% CP (w%) (Gal-C-MEs) had a well-defined spherical shape with a small size (47.63 ± 1.41 nm), a narrow polydispersity index (PDI, 0.101 ± 0.002), and a nearly neutral surface charge (-4.37 ± 1.76 mV). The half-maximal inhibitory concentration (IC50) of Gal-C-MEs against HepG2 cells was 70.2 μg/mL, which decreased by 1.8-fold in comparison with that of coix seed multicomponent microemulsions (C-MEs). The fluorescence intensity of fluorescein isothiocyanate (FITC)-loaded Gal-C-MEs (FITC-Gal-C-MEs) internalized by HepG2 cells was 1.8-fold higher than that of FITC-loaded C-MEs (FIT C-C-MEs), but the cellular uptake of the latter became reduce by 1.6-fold when the weight ratio of CP decreased up to 10%. In the cell apoptosis studies, C-MEs (containing 30% CP) did not show a significant difference with Gal-C-MEs, but exhibited 3.3-fold and 1.5-fold increase relative to C-MEs containing 10% CP and 20% CP, respectively. In the in vivo tumor targeting studies, Cy5-loaded Gal-C-MEs (Cy5-Gal-C-MEs), notably distributed in the tumor sites and still found even at 48 h post-administration, displayed the strongest capability of tumor tissue accumulation and retention among all the test groups. Most importantly, Gal-C-MEs had stronger inhibition of tumor growth, prolonged survival time and more effectively tumor cell apoptosis induction in comparison with C-MEs containing different amounts of CP, which further confirmed that a certain amount of CP and tumor-targeted ligand were of great importance to potent anticancer efficacy. The aforementioned results suggested that Gal-C-MEs presented promising potential as a highly effective and safe anticancer drug delivery system for enhanced liver cancer delivery.