Infiltrating mast cells enhance prostate cancer invasion via altering LncRNA-HOTAIR/PRC2-androgen receptor (AR)-MMP9 signals and increased stem/progenitor cell population

The prognostic significance of CD117-positive mast cells and microvessel density in colorectal cancer

The prognostic significance of angiogenesis has been demonstrated in various types of cancer. However, in colorectal cancer (CRC), there are conflicting results regarding the relationship between angiogenesis and clinical-histopathological prognostic factors. Mast cells are immune system cells found in the inflammatory microenvironment; their role in carcinogenesis and prognosis remains unclear although they are considered to cause cancer development and progression. The present study aims to evaluate the prognostic significance of mast cell accumulation and angiogenesis assessed by microvessel density (MVD) in patients with CRC. Patients who underwent curative resection and who were not treated with neoadjuvant chemotherapy were included. The anti-CD34 antibody and anti-CD117 antibody were utilized for the immunohistochemical assessment of MVD and the mast cell count (MCC) in the tissue samples, respectively. The relationship between MCC, MVD, survival and clinical-histopathological prognostic factors were evaluated. A total of 94 patients were enrolled to the study. In a median 49-month follow-up, 65 patients (69.1%) died. The 5-year disease-free survival was 61.1% and 31.3% for the group with CD34 < 18.3% and CD34 > 18.3%, respectively (P = .001). The same groups presented 5-year overall survival rates of 77, 1% and 51, 4%, respectively (P, .012). The MVD was found to be associated with the pathological T stage, lymph node metastasis and distant metastasis (P < .05). Although the MCC was positively correlated with MVD, there was no association between the MCC and clinical-histopathological prognostic factors. MVD-assessed angiogenesis was significantly related to survival and the clinical-histopathological prognostic factors in patients diagnosed with CRC.

An extensive overview of the role of lncRNAs generated from immune cells in the etiology of cancer

Long non-coding RNAs (lncRNAs) are involved in the control of critical tumor-suppressor and oncogenic pathways in cancer. These types of non-coding RNAs could affect both immune and cancer cells. The thorough analysis of lncRNAs derived from immune cells and the incorporation of new findings significantly advance our understanding of the complex role of lncRNAs in the context of cancer. This work highlights the promise of lncRNAs for translational therapeutic approaches while also establishing a solid foundation for comprehending the complex link between lncRNAs and cancer through a coherent narrative. The main findings of this article are that types of lncRNAs derived from immune cells, such as MM2P and MALAT1, can affect the behaviors of cancer cells, like invasion, angiogenesis, and proliferation. As research in this area grows, the therapeutic potential of targeting these lncRNAs offers promising opportunities for expanding our understanding of cancer biology and developing cutting-edge, precision-based therapies for cancer therapy.

Role of mast cells activation in the tumor immune microenvironment and immunotherapy of cancers

The mast cell is an important cellular component that plays a crucial role in the crosstalk between innate and adaptive immune responses within the tumor microenvironment (TME). Recently, numerous studies have indicated that mast cells related to tumors play a dual role in regulating cancers, with conflicting results seemingly determined by the degranulation medium. As such, mast cells are an ignored but very promising potential target for cancer immunotherapy based on their immunomodulatory function. In this review, we present a comprehensive overview of the roles and mechanisms of mast cells in diverse cancer types. Firstly, we evaluated the infiltration density and location of mast cells on tumor progression. Secondly, mast cells are activated by the TME and subsequently release a range of inflammatory mediators, cytokines, chemokines, and lipid products that modulate their pro-or anti-tumor functions. Thirdly, activated mast cells engage in intercellular communication with other immune or stromal cells to modulate the immune status or promote tumor development. Finally, we deliberated on the clinical significance of targeting mast cells as a therapeutic approach to restrict tumor initiation and progression. Overall, our review aims to provide insights for future research on the role of mast cells in tumors and their potential as therapeutic targets for cancer treatment.

Inflammation in Prostate Cancer: Exploring the Promising Role of Phenolic Compounds as an Innovative Therapeutic Approach

Prostate cancer (PCa) remains a significant global health concern, being a major cause of cancer morbidity and mortality worldwide. Furthermore, profound understanding of the disease is needed. Prostate inflammation caused by external or genetic factors is a central player in prostate carcinogenesis. However, the mechanisms underlying inflammation-driven PCa remain poorly understood. This review dissects the diagnosis methods for PCa and the pathophysiological mechanisms underlying the disease, clarifying the dynamic interplay between inflammation and leukocytes in promoting tumour development and spread. It provides updates on recent advances in elucidating and treating prostate carcinogenesis, and opens new insights for the use of bioactive compounds in PCa. Polyphenols, with their noteworthy antioxidant and anti-inflammatory properties, along with their synergistic potential when combined with conventional treatments, offer promising prospects for innovative therapeutic strategies. Evidence from the use of polyphenols and polyphenol-based nanoparticles in PCa revealed their positive effects in controlling tumour growth, proliferation, and metastasis. By consolidating the diverse features of PCa research, this review aims to contribute to increased understanding of the disease and stimulate further research into the role of polyphenols and polyphenol-based nanoparticles in its management.

Non-coding RNAs in enzalutamide resistance of castration-resistant prostate cancer

Enzalutamide (Enz) is a next-generation androgen receptor (AR) antagonist used to treat castration-resistant prostate cancer (CRPC). Unfortunately, the relapsing nature of CRPC results in the development of Enz resistance in many patients. Non-coding RNAs (ncRNAs) are RNA molecules that do not encode proteins, which include microRNAs (miRNA), long ncRNAs (lncRNAs), circular RNAs (circRNAs), and other ncRNAs with known and unknown functions. Recently, dysregulation of ncRNAs in CRPC, particularly their regulatory function in drug resistance, has attracted more and more attention. Herein, we introduce the roles of dysregulation of different ncRNAs subclasses in the development of CRPC progression and Enz resistance. Recently determined mechanisms of Enz resistance are discussed, focusing mainly on the role of AR-splice variant-7 (AR-V7), mutations, circRNAs and lncRNAs that act as miRNA sponges. Also, the contributions of epithelial-mesenchymal transition and glucose metabolism to Enz resistance are discussed. We summarize the different mechanisms of miRNAs, lncRNAs, and circRNAs in the progression of CRPC and Enz resistance, and highlight the prospect of future therapeutic strategies against Enz resistance.

Non-coding RNAs: emerging roles in the characterization of immune microenvironment and immunotherapy of prostate cancer

Prostate cancer is the most common tumor among men. Although the prognosis for early-stage prostate cancer is good, patients with advanced disease often progress to metastatic castration-resistant prostate cancer (mCRPC), which usually leads to death owing to resistance to existing treatments and lack of long-term effective therapy. In recent years, immunotherapy, especially immune checkpoint inhibitors (ICIs), has made great progress in the treatment of various solid tumors, including prostate cancer. However, the ICIs have only shown modest outcomes in mCRPC compared with other tumors. Previous studies have suggested that the suppressive tumor immune microenvironment (TIME) of prostate cancer leads to poor anti-tumor immune response and tumor resistance to immunotherapy. It has been reported that non-coding RNAs (ncRNAs) are capable of regulating upstream signaling at the transcriptional level, leading to a "cascade of changes" in downstream molecules. As a result, ncRNAs have been identified as an ideal class of molecules for cancer treatment. The discovery of ncRNAs provides a new perspective on TIME regulation in prostate cancer. ncRNAs have been associated with establishing an immunosuppressive microenvironment in prostate cancer through multiple pathways to modulate the immune escape of tumor cells which can promote resistance of prostate cancer to immunotherapy. Targeting these related ncRNAs presents an opportunity to improve the effectiveness of immunotherapy in this patient population.

Mast cell ontogeny: From fetal development to life-long health and disease

Mast cells (MCs) are evolutionarily ancient innate immune cells with important roles in protective immunity against bacteria, parasites, and venomous animals. They can be found in most organs of the body, where they also contribute to normal tissue functioning, for example by engaging in crosstalk with nerves. Despite this, they are most widely known for their detrimental roles in allergy, anaphylaxis, and atopic disease. Just like macrophages, mast cells were conventionally thought to originate from the bone marrow. However, they are already present in fetal tissues before the onset of bone marrow hematopoiesis, questioning this dogma. In recent years, our view of myeloid cell ontogeny has been revised. We now know that the first mast cells originate from progenitors made in the extra-embryonic yolk sac, and later get supplemented with mast cells produced from subsequent waves of hematopoiesis. In most connective tissues, sizeable populations of fetal-derived mast cells persist into adulthood, where they self-maintain largely independently from the bone marrow. These developmental origins are highly reminiscent of macrophages, which are known to have critical functions in development. Mast cells too may thus support healthy development. Their fetal origins and longevity also make mast cells susceptible to genetic and environmental perturbations, which may render them pathological. Here, we review our current understanding of mast cell biology from a developmental perspective. We first summarize how mast cell populations are established from distinct hematopoietic progenitor waves, and how they are subsequently maintained throughout life. We then discuss what functions mast cells may normally have at early life stages, and how they may be co-opted to cause, worsen, or increase susceptibility to disease.

Single-cell transcriptomic analysis of normal and pathological tissues from the same patient uncovers colon cancer progression

The aim of the present study was to elucidate the evolutionary trajectory of colon cells from normal colon mucosa, to adenoma, then to carcinoma in the same microenvironment. Normal colon, adenoma and carcinoma tissues from the same patient were analyzed by single-cell sequencing, which perfectly simulated the process of time-dependent colon cancer due to the same microenvironment. A total of 22 cell types were identified. Results suggest the presence of dominant clones of same cells including C2 goblet cell, epithelial cell subtype 1 (Epi1), enterocyte cell subset 0 (Entero0), and Entero5 in carcinoma. Epi1 and Entero0 were Co-enriched in antibacterial and IL-17 signaling, Entero5 was enriched in immune response and mucin-type O-glycan biosynthesis. We discovered new colon cancer related genes including AC007952.4, NEK8, CHRM3, ANO7, B3GNT6, NEURL1, ODC1 and KCNMA1. The function of TBC1D4, LTB, C2CD4A, AND GBP4/5 in T cells needs to be clarified. We used colon samples from the same person, which provide new information for colon cancer therapy.

Impact of Immune Cells in the Tumor Microenvironment of Prostate Cancer Metastasis

Prostate cancer is the most prevalent type of cancer in senior American men. Currently, the five-year survival rate after the initial diagnosis of prostate cancer is close to 100%. However, it is also the second leading cause of cancer death in senior men due to the dissemination of prostate cancer cells outside of the prostate causing growth in other organs, known as metastatic prostate cancer. The tumor microenvironment (TME) plays a critical role in the development, progression and metastasis of prostate cancer. One of the major components of the TME contains various types of immune cells, often recruited by cancer cells to the cancer formation areas. The interactions among prostate cancer cells and the infiltrating immune cells affect the outcome of prostate cancer. Here, we summarize the mechanisms various infiltrating immune cells use to regulate prostate cancer metastasis and possibly lead to the development of treatment strategies. Furthermore, the information here may also give rise to preventative strategies that focus on targeting the TME of prostate cancer patients.

Mast cells and tryptase are linked to itch and disease severity in mycosis fungoides: Results of a pilot study

Introduction

In mycosis fungoides (MF), the most common cutaneous T-cell lymphoma, itch is a frequent clinical symptom. Whether mast cells (MCs), eosinophils (Eos) or their mediators play a role in MF-associated itch or disease severity is controversially discussed. Here, we explored the role of MC and Eo numbers in the skin as well as blood levels of their mediators in disease severity and itch.

Methods

In 10 patients with MF and 10 matched control subjects we assessed disease severity, itch, and quality of life impairment using dedicated tools such as the mSWAT, ItchyQoL and DLQI. We analyzed skin biopsies and measured serum levels of tryptase, a mast cell mediator, as well as of the eosinophil products eosinophil cationic protein (ECP) and major basic protein (MBP).

Results

The presence of chronic itch, in four of 10 patients, was associated with significantly higher disease severity (mSwat), larger body surface area affected, and stronger QoL impairment (Itchy-Qol, DLQI). Serum levels of tryptase, but not ECP and MBP, were linked with patient-reported disease severity, body surface area affected, and the presence of itch. Three of the four patients with chronic itch, but none of the six patients without, had tryptase levels above &gt;6µg/l. Numbers of MCs in the papillary dermis were higher in MF skin lesions then in non-lesional skin of MF patients and skin of healthy controls.

Discussion

The MC-mediator tryptase, in MF, is linked to disease activity and impact, most prominently to itch. Our findings call for larger studies that explore the role of MCs, tryptase and other MC mediators as drivers of itch and their role in MF pathogenesis.

Molecular and cellular functions of long non-coding RNAs in prostate and breast cancer

Long noncoding RNAs (lncRNAs) are defined as noncoding RNA transcripts with a length greater than 200 nucleotides. Research over the last decade has made great strides in our understanding of lncRNAs, especially in the biology of their role in cancer. In this article, we will briefly discuss the biogenesis and characteristics of lncRNAs, then review their molecular and cellular functions in cancer by using prostate and breast cancer as examples. LncRNAs are abundant, diverse, and evolutionarily, less conserved than protein-coding genes. They are often expressed in a tumor and cell-specific manner. As a key epigenetic factor, lncRNAs can use a wide variety of molecular mechanisms to regulate gene expression at each step of the genetic information flow pathway. LncRNAs display widespread effects on cell behavior, tumor growth, and metastasis. They act intracellularly and extracellularly in an autocrine, paracrine and endocrine fashion. Increased understanding of lncRNA's role in cancer has facilitated the development of novel biomarkers for cancer diagnosis, led to greater understanding of cancer prognosis, enabled better prediction of therapeutic responses, and promoted identification of potential targets for cancer therapy.

The Crossroads of Periodontitis and Oral Squamous Cell Carcinoma: Immune Implications and Tumor Promoting Capacities

Periodontitis (PD) is increasingly considered to interact with and promote a number of inflammatory diseases, including cancer. In the case of oral squamous cell carcinoma (OSCC) the local inflammatory response associated with PD is capable of triggering altered cellular events that can promote cancer cell invasion and proliferation of existing primary oral carcinomas as well as supporting the seeding of metastatic tumor cells into the gingival tissue giving rise to secondary tumors. Both the immune and stromal components of the periodontium exhibit phenotypic alterations and functional differences during PD that result in a microenvironment that favors cancer progression. The inflammatory milieu in PD is ideal for cancer cell seeding, migration, proliferation and immune escape. Understanding the interactions governing this attenuated anti-tumor immune response is vital to unveil unexplored preventive or therapeutic possibilities. Here we review the many commonalities between the oral-inflammatory microenvironment in PD and oral-inflammatory responses that are associated with OSCC progression, and how these conditions can act to promote and sustain the hallmarks of cancer.

Mast Cell–Tumor Interactions: Molecular Mechanisms of Recruitment, Intratumoral Communication and Potential Therapeutic Targets for Tumor Growth

Mast cells (MCs) are tissue-resident immune cells that are important players in diseases associated with chronic inflammation such as cancer. Since MCs can infiltrate solid tumors and promote or limit tumor growth, a possible polarization of MCs to pro-tumoral or anti-tumoral phenotypes has been proposed and remains as a challenging research field. Here, we review the recent evidence regarding the complex relationship between MCs and tumor cells. In particular, we consider: (1) the multifaceted role of MCs on tumor growth suggested by histological analysis of tumor biopsies and studies performed in MC-deficient animal models; (2) the signaling pathways triggered by tumor-derived chemotactic mediators and bioactive lipids that promote MC migration and modulate their function inside tumors; (3) the possible phenotypic changes on MCs triggered by prevalent conditions in the tumor microenvironment (TME) such as hypoxia; (4) the signaling pathways that specifically lead to the production of angiogenic factors, mainly VEGF; and (5) the possible role of MCs on tumor fibrosis and metastasis. Finally, we discuss the novel literature on the molecular mechanisms potentially related to phenotypic changes that MCs undergo into the TME and some therapeutic strategies targeting MC activation to limit tumor growth.

Interaction between Non-Coding RNAs and Androgen Receptor with an Especial Focus on Prostate Cancer

The androgen receptor (AR) is a member of the nuclear receptor superfamily and has three functional domains, namely the N-terminal, DNA binding, and C-terminal domain. The N-terminal domain harbors potent transactivation functions, whereas the C-terminal domain binds to androgens and antiandrogens used to treat prostate cancer. AR has genomic activity being DNA binding-dependent or through interaction with other DNA-bound transcription factors, as well as a number of non-genomic, non-canonical functions, such as the activation of the ERK, AKT, and MAPK pathways. A bulk of evidence indicates that non-coding RNAs have functional interactions with AR. This type of interaction is implicated in the pathogenesis of human malignancies, particularly prostate cancer. In the current review, we summarize the available data on the role of microRNAs, long non-coding RNAs, and circular RNAs on the expression of AR and modulation of AR signaling, as well as the effects of AR on their expression. Recognition of the complicated interaction between non-coding RNAs and AR has practical importance in the design of novel treatment options, as well as modulation of response to conventional therapeutics.

The Role of Androgen Receptor in Cross Talk Between Stromal Cells and Prostate Cancer Epithelial Cells

Prostate cancer (PCa) lists as the second most lethal cancer for men in western countries, and androgen receptor (AR) plays a central role in its initiation and progression, which prompts the development of androgen deprivation therapy (ADT) as the standard treatment. Prostate tumor microenvironment, consisting of stromal cells and extracellular matrix (ECM), has dynamic interactions with PCa epithelial cells and affects their growth and invasiveness. Studies have shown that both genomic and non-genomic AR signaling pathways are involved in the biological regulation of PCa epithelial cells. In addition, AR signaling in prostate stroma is also involved in PCa carcinogenesis and progression. Loss of AR in PCa stroma is clinically observed as PCa progresses to advanced stage. Especially, downregulation of AR in stromal fibroblasts dysregulates the expression levels of ECM proteins, thus creating a suitable environment for PCa cells to metastasize. Importantly, ADT treatment enhances this reciprocal interaction and predisposes stromal cells to promote cell invasion of PCa cells. During this process, AR in PCa epithelium actively responds to various stimuli derived from the surrounding stromal cells and undergoes enhanced degradation while elevating the expression of certain genes such as MMP9 responsible for cell invasion. AR reduction in epithelial cells also accelerates these cells to differentiate into cancer stem-like cells and neuroendocrine cells, which are AR-negative PCa cells and inherently resistant to ADT treatments. Overall, understanding of the cross talk between tumor microenvironment and PCa at the molecular level may assist the development of novel therapeutic strategies against this disease. This review will provide a snapshot of AR's action when the interaction of stromal cells and PCa cells occurs.

Role of long non-coding RNA in regulating polarization of gastric cancer macrophages

Tumor-associated macrophages (TAMs) are an important part of the tumor microenvironment. They are distributed in tumor tissues and distant metastatic sites, and are related to tumor progression and prognosis. TAMs M2 can promote tumor biological processes such as tumor proliferation, invasion, and metastasis, and inhibit apoptosis, and are obviously related to the poor prognosis of tumor patients. In recent years, the role of long non-coding RNAs (lncRNAs) in regulating the polarization of macrophages has gradually been revealed, which can affect the occurrence and development of tumors by adjusting the polarization of macrophages. Studies have shown that lncRNAs play an important role in the polarization process of gastric cancer macrophages. This article summarizes the related research reports, hoping to provide ideas for studies that interfere with the polarization process of TAMs to inhibit tumor progression.

Histamine in cancer immunology and immunotherapy. Current status and new perspectives

Cancer is the second leading cause of death globally and its incidence and mortality are rapidly increasing worldwide. The dynamic interaction of immune cells and tumor cells determines the clinical outcome of cancer. Immunotherapy comes to the forefront of cancer treatments, resulting in impressive and durable responses but only in a fraction of patients. Thus, understanding the characteristics and profiles of immune cells in the tumor microenvironment (TME) is a necessary step to move forward in the design of new immunomodulatory strategies that can boost the immune system to fight cancer. Histamine produces a complex and fine-tuned regulation of the phenotype and functions of the different immune cells, participating in multiple regulatory responses of the innate and adaptive immunity. Considering the important actions of histamine-producing immune cells in the TME, in this review we first address the most important immunomodulatory roles of histamine and histamine receptors in the context of cancer development and progression. In addition, this review highlights the current progress and foundational developments in the field of cancer immunotherapy in combination with histamine and pharmacological compounds targeting histamine receptors.

HOTAIR beyond repression: In protein degradation, inflammation, DNA damage response, and cell signaling

Long noncoding RNAs (lncRNAs) are pervasively transcribed from the mammalian genome as transcripts that are usually >200 nucleotides long. LncRNAs generally do not encode proteins but are involved in a variety of physiological processes, principally as epigenetic regulators. HOX transcript antisense intergenic RNA (HOTAIR) is a well-characterized lncRNA that has been implicated in several cancers and in various other diseases. HOTAIR is a repressor lncRNA and regulates various repressive chromatin modifications. However, recent studies have revealed additional functions of HOTAIR in regulation of protein degradation, microRNA (miRNA) sponging, NF-κB activation, inflammation, immune signaling, and DNA damage response. Herein, we have summarized the diverse functions and modes of action of HOTAIR in protein degradation, inflammation, DNA repair, and diseases, beyond its established functions in gene silencing.

MiR-133b inhibits colorectal cancer metastasis via lncRNA-LUCAT1

Aim: Colorectal cancer (CRC) is a common malignant tumor of the digestive system. Metastasis is the leading cause of poor prognosis of CRC patients, warranting further study of the molecular mechanism of metastasis in CRC and identification of new therapeutic targets. MiR-133b has been proven to play an important role in tumorigenesis by directly targeting coding genes. However, whether miR-133b can regulate tumorigenesis via long noncoding RNA (lncRNA) remains unclear. Methods: We systematically analyzed the expression level and correlation of miR-133b and LUCAT1 in cancer tissues and adjacent tissues from 30 patients with CRC. The effects of miR-133b and LUCAT1 on the invasive ability of CRC cells were detected by a transwell assay. The relationship between miR-133b and LUCAT1 was investigated by cells transfection experiments, rescue experiments and luciferase reporter assays. The binding of LUCAT1 and EZH2 was detected by RNA immunoprecipitation assay. Results: MiR-133b was expressed at low levels in CRC tissues, and LUCAT1 was highly expressed, with an inverse correlation between them. LUCAT1 promoted the migration and invasion of HCT116 and SW620 cells. Overexpression of LUCAT1 attenuated the inhibition of cell migration and invasion induced by miR-133b. However, the dual luciferase assay showed that miR-133b did not directly target LUCAT1. Conclusion: MiR-133b affects CRC metastasis via the LUCAT1/EZH2 complex. MiR-133b and LUCAT1 may be potential targets for antimetastasis therapy in CRC.

A microRNA-Messenger RNA Regulatory Network and Its Prognostic Value in Cervical Cancer

Cervical cancer (CC) is the fourth commonest cancer in women worldwide. Increasing evidence proves that microRNA (miRNA)-messenger RNA (mRNA) network is involved in CC. In this study, miRNA and mRNA expression profiles were downloaded from The Cancer Genome Atlas (TCGA) database. Differently expressed miRNAs (DE-miRNAs) and mRNAs (DE-mRNAs) were obtained by "Empirical Analysis of Digital Gene Expression Data in R (EdgeR)" package. Then, functional analyses were conducted. With Cytoscape software, a protein-protein interaction (PPI) network was established to identify hub genes that were used for building an miRNA-hub gene network. Next, a prognostic signature based on hub genes was constructed by Cox regression analysis, and its prognostic value was assessed by a nomogram. Finally, the relationship between immune cell infiltration and the three genes in the prognostic model was investigated by using the CIBERSORT algorithm. We screened out 5096 DE-mRNAs and 114 DE-miRNAs between healthy cervical and CC tissues. Then, 102 target DE-mRNAs of upregulated DE-miRNAs and 150 target DE-mRNAs of downregulated DE-miRNAs were obtained. PPI network demonstrated 20 hub nodes with higher connectivity. DE-mRNAs were mostly enriched in pathways in cancer, cell cycle, and proteoglycans in cancer. The miRNA-hub gene network showed that most hub genes could be potentially modulated by miR-200c-3p, miR-23b-3p, and miR-106b-5p. Quantitative real-time PCR proved that 10 miRNAs were downregulated and 6 mRNAs were upregulated markedly in CC tissues. Furthermore, a prognostic signature was established based on enhancer of zeste homolog 2 (EZH2), Fms-related tyrosine kinase 1 (FLT1), and glyceraldehyde 3-phosphate dehydrogenase (GAPDH). The area under the curve value of the 5-year receiver operating characteristic curve was 0.609. The three genes were also found to be related to the infiltration of six types of immune cells, including dendritic cells, macrophages M0 and M1, mast cells, and monocytes. In conclusion, the development of CC is regulated by the miRNA-mRNA network we proposed in this study.

The evolution of long noncoding RNA acceptance in prostate cancer initiation, progression, and its clinical utility in disease management

CONTEXT

It is increasingly evident that non-protein-coding regions of the genome can give rise to transcripts that form functional layers of the cancer genome. One of most abundant classes in these regions is long noncoding RNAs (lncRNAs). They have gained increasing attention in prostate cancer (PCa) and paved the way for a greater understanding of these cryptic regulators in cancer.

OBJECTIVE

To review current research exploring the functional biology of lncRNAs in PCa over the past three decades.

EVIDENCE ACQUISITION

A systematic review was performed using PubMed to search for reports with terms "long noncoding RNA", "prostate", and "cancer" over the past 30 yr (1988-2018).

EVIDENCE SYNTHESIS

We comprehensively surveyed the literature collected and summarise experiments leading to the characterisation of lncRNAs in PCa. A historical timeline of lncRNA identification is described, where each lncRNA is categorised mechanistically and within the primary areas of carcinogenesis: tumour risk and initiation, tumour promotion, tumour suppression, and tumour treatment resistance. We describe select lncRNAs that exemplify these areas. We also review whether these lncRNAs have a clinical utility in PCa diagnosis, prognosis, and prediction, and as therapeutic targets.

CONCLUSIONS

The biology of lncRNA is multifaceted, demonstrating a complex array of molecular and cellular functions. These studies reveal that lncRNAs are involved in every stage of PCa. Their clinical utility for diagnosis, prognosis, and prediction of PCa is well supported, but further evaluation for their therapeutic candidacy is needed. We provide a detailed resource and view inside the lncRNA landscape for other cancer biologists, oncologists, and clinicians.

PATIENT SUMMARY

In this study, we review current knowledge of the non-protein-coding genome in prostate cancer (PCa). We conclude that many of these regions are functional and a source of accurate biomarkers in PCa. With a strong research foundation, they hold promise as future therapeutic targets, yet clinical trials are necessary to determine their intrinsic value to PCa disease management.

The long noncoding RNA CTA-941F9.9 is frequently downregulated and may serve as a biomarker for carcinogenesis in colorectal cancer

BACKGROUND

Long noncoding RNAs (lncRNAs) participate in the carcinogenesis of many different cancers. This study aimed to detect expression of lncRNA CTA-941F9.9 in colorectal cancer tissues compared with matched nontumorous adjacent tissues (NATs). Moreover, we investigated whether this molecule is able to influence carcinogenesis in colorectal cancer (CRC).

METHODS

Colorectal cancer tissues and NATs from two cohorts of patients were examined. Quantitative PCR was performed to quantify levels of CTA-941F9.9 expression in these samples. The association between CTA-941F9.9 expression and clinicopathological features, including receiver operating characteristic (ROC) curves, was also analyzed to evaluate the diagnostic value of CTA-941F9.9 in CRC. Potential effects of lncRNA CTA-941F9.9 on CRC cells were assessed via autophagy, transwell assay, CCK8 assays, and flow cytometry.

RESULTS

Our experimental results showed lncRNA CTA-941F9.9 to be significantly downregulated in CRC tissues in both cohorts, with areas under the ROC curve (AUC) of 0.802 and 0.876. However, no significant correlations between CTA-941F9.9 expression levels and clinicopathological characteristics or patient outcomes were observed. We also found that CTA-941F9.9 promotes autophagy in CRC cell lines but no significant function of CTA-941F9.9 in regulating cancer cell proliferation or migration.

CONCLUSIONS

LncRNA CTA-941F9.9 is frequently downregulated in CRC compared with NATs and might play an important role in CRC carcinogenesis.

LncRNA HOTAIR in Tumor Microenvironment: What Role?

lncRNAs participate in many cellular processes, including regulation of gene expression at the transcriptional and post-transcriptional levels. In addition, many lncRNAs can contribute to the development of different human diseases including cancer. The tumor microenvironment (TME) plays an important role during tumor growth and metastatic progression, and most of these lncRNAs have a key function in TME intracellular signaling. Among the numerous identified lncRNAs, several experimental evidences have shown the fundamental role of the lncRNA HOTAIR in carcinogenesis, also highlighting its use as a circulating biomarker. In this review we described the contribution of HOTAIR in the TME modulation, highlighting its relation with cellular and non-cellular components during tumor evolution and progression.

Mast Cells as an Indicator and Prognostic Marker in Molecular Subtypes of Breast Cancer

BACKGROUND/AIM

Mast cells (MCs) represent the most controversial non-malignant element of the tumor microenvironment. Our aim was to study how MCs density and distribution (intratumoral-MCit versus peritumoral-MCpt) relate to tumor grade and molecular subtypes.

MATERIALS AND METHODS

MCs tryptase immunohistochemistry was performed on 80 cases of breast carcinomas.

RESULTS

For Luminal A tumors, a partial correlation was detected between MCit and progesterone receptor (PR) (p=0.005). Luminal B tumors showed a significant correlation between MCpt and age (p=0.009), estrogen receptor (ER) (p=0.017) and PR (p=0.035). MCit and MCpt were strongly interrelated in this subtype (p=0.002) and in triple-negative breast cancers (p=0.002). In HER2 subtype, MCpt tumors were significantly correlated with HER2 (p=0.044). In G2 tumors, MCpt correlated with ER (p=0.015) and PR (p=0.038) while in G3 tumors ER correlated with both MCit (p=0.009) and MCpt (p=0.000487) tumors.

CONCLUSION

MCs dynamics are strongly influenced by hormone receptors and HER2 status. MCit increased in aggressive tumor types and is a worse prognostic factor.

ADT with antiandrogens in prostate cancer induces adverse effect of increasing resistance, neuroendocrine differentiation and tumor metastasis

Prostate cancer (PCa) is the most common cancer and the 2nd leading cause of cancer-related deaths among men in the United States. Androgen-deprivation-therapy (ADT) with antiandrogens to target the androgens/androgen receptor (AR) signals remains the standard therapy for advanced PCa. However, most of the PCa patients who received ADT with antiandrogens, including the recently developed Enzalutamide (Enz) that might extend PCa patients survival an extra 4.8 months, will still develop the castration (or antiandrogen) resistance. Mechanism dissection studies suggest these antiandrogen resistances may involve the induction of AR splicing variants and/or AR mutants. Further preclinical in vitro/in vivo studies suggest ADT-antiandrogens may also enhance the neuroendocrine differentiation (NED) and PCa cell invasion, and these unwanted side-effects may function through various mechanisms including altering the infiltrating inflammatory cells within the prostate tumor microenvironment. This review summarizes these unwanted ADT-induced side-effects and discusses multiple approaches to overcome these side-effects to better suppress the PCa at the castration resistant stage.

Long non-coding RNA NIFK-AS1 inhibits M2 polarization of macrophages in endometrial cancer through targeting miR-146a

Accumulating evidence suggested that tumor-associated macrophages played crucial roles in the progression of endometrial cancer. The aim of this study was to determine the role of lncRNA NIFK-AS1 in M2-like polarization of macrophages and further to investigate the effect of NIFK-AS1 modulating macrophage polarization on the proliferation, migration and invasion of endometrial cancer cells. Human peripheral blood mononuclear cells and tumor-associated macrophages were isolated from healthy volunteers and endometrial cancer patients, respectively. The expression of NIFK-AS1 and miR-146a were detected by qRT-PCR in tumor-associated macrophages or THP-1 monocytes differentiated macrophages. The expression of NIFK-AS1 and miR-146a were decreased and increased in tumor-associated macrophages of endometrial cancer patients, respectively. NIFK-AS1 overexpression suppressed the IL-4-induced M2 polarization of THP-1 macrophages. Moreover, we found that NIFK-AS1 overexpression inhibited the 17β-estradiol-induced proliferation, migration and invasion of endometrial cancer cells through suppressing M2-like polarization of macrophages. NIFK-AS1 could interact with miR-146a and increased the expression of Notch1 through downregulating miR-146a. Further experiments revealed that miR-146a overexpression attenuated the effect of NIFK-AS1 on suppressing the M2 polarization of macrophages and the estrogen-induced proliferation, migration and invasion of endometrial cancer cells. These findings indicated that NIFK-AS1 inhibited the M2-like polarization of macrophages via targeting miR-146a, thereby reducing the estrogen-induced proliferation, migration and invasion of endometrial cancer cells. Our study highlights the important role of NIFK-AS1 in regulating the polarization and function of tumor-associated macrophages in endometrial cancer and provides novel insight into the TAMs-mediated progression of endometrial cancer.

[Infiltrating mast cells promote neuroendocrine differentiation and increase docetaxel resistance of prostate cancer cells by up-regulating p21]

OBJECTIVE

To investigate the effect of infiltrating mast cells on neuroendocrine differentiation (NED) and docetaxel sensitivity of prostate cancer (PCa) cells in vitro.

METHODS

Human PCa cell lines (LNCaP and C4-2) were co-cultured with human mast cell line (HMC-1) in Transwell chambers. Androgen receptor (AR) was silenced in C4-2 cells using sh-AR lentivirus, and p21 was knocked down and overexpressed by transfecting C4-2 cells with pLKO.1-sh-p21 and pCMV-p21, respectively. The morphological changes of LNCaP and C4-2 cells were observed. MTT assay and colony formation assay were used to assess the proliferation of LNCaP and C4-2 cells. CCK8 assay was used to detect the cell viability of C4-2 cells following docetaxel trreatment. RT-qPCR and Western blotting were performed to determine the mRNA and protein expressions of neuroendocrine markers, AR and p21 in the cells.

RESULTS

Co-culture with HMC-1 cells enhanced the neuroendocrine phenotypes, inhibited the proliferation and up-regulated the expression of p21 in LNCaP and C4-2 cells. P21 positively regulated NED through a non-AR-dependent signaling pathway, while p21 knockdown partially reversed NED promoted by the mast cells. PCa cells co-cultured with HMC-1 cells showed increased resistance to docetaxel, and silencing p21 partially reversed docetaxel resistance in PCa cells.

CONCLUSION

Infiltrating mast cells up-regulates p21 to promote NED and increase docetaxel resistance in PCa cells in vitro.

The use of long non-coding RNAs as prognostic biomarkers and therapeutic targets in prostate cancer

Prostate cancer is the most common cancer in men and the second leading cause of cancer-related deaths. The most used biomarker to detect prostate cancer is Prostate Specific Antigen (PSA), whose levels are measured in serum. However, it has been recently established that molecular markers of cancer should not be based solely on genes and proteins but should also reflect other genomic traits; long non-coding RNAs (lncRNAs) serve this purpose. lncRNAs are transcripts of >200 bases that do not encode proteins and that have been shown to display abnormal expression profiles in different types of cancer. Experimental studies have highlighted lncRNAs as potential biomarkers for prognoses and treatments in patients with different types of cancer, including prostate cancer, where the PCA3 lncRNA is currently used as a diagnostic tool and management strategy. With the development of genomic technologies, particularly next-generation sequencing (NGS), several other lncRNAs have been linked to prostate cancer and are currently under validation for their medical use. In this review, we will discuss different strategies for the discovery of novel lncRNAs that can be evaluated as prognostic biomarkers, the clinical impact of these lncRNAs and how lncRNAs can be used as potential therapeutic targets.

Genetic variation of long non-coding RNA TINCR contribute to the susceptibility and progression of colorectal cancer

Colorectal cancer (CRC) accounts for the leading causes of cancer-related morbidity and mortality. However, a large part of heritable factors are warranted to be explored. Long non-coding RNAs (lncRNAs) serve critical roles in cancer development and progression. Herein, we explored effect of genetic variants of Tissue differentiation-inducing non-protein coding RNA (TINCR), a key lncRNA required for somatic tissue differentiation and tumor progression, on risk and progression of CRC. Three tagSNPs, including rs2288947, rs8105637, and rs12610531, were evaluated in in a two-stage, case-control study. Two SNPs, rs2288947 and rs8105637, were significantly associated with susceptibility of CRC in both stages. When pooled together, the allele G was significantly associated with 23% decreased risk of CRC (OR=0.77; 95% CI=0.67-0.88; P value = 1.2×10-4)for SNP rs2288947. While for SNP rs8105637, the allele A was significantly associated with 22% increased risk of CRC (OR=1.22; 95% CI=1.09-1.37; P value = 6.2×10-4). The two SNPs were also statistically associated with occurrence of lymph node metastasis of CRC. The carriers of allele G are less likely to get lymph node metastasis (OR=0.77; 95% CI=0.63-0.94; P value = 0.011) for rs2288947, and the carriers of allele A are more likely to get lymph node metastasis (OR=1.22; 95% CI=1.03-1.43; P value = 0.019) for rs8105637. These results suggest that lncRNA TINCR polymorphisms may be implicated in the development and progression of CRC.

Influence of HOTAIR rs920778 and rs12826786 genetic variants on prostate cancer risk and progression-free survival

Aim: Evaluate the impact of the single nucleotide polymorphisms rs920778 and rs12826786 in the long noncoding RNA HOTAIR in the susceptibility and prognosis of prostate cancer (PCa) patients. Patients & methods: HOTAIR single nucleotide polymorphisms were genotyped by restriction fragment length polymorphism in 151 PCa cases and 180 cancer-free controls. Odds ratio, 95% CIs and prognostic significance were calculated. Results: Our data showed no statistically significant associations between HOTAIR polymorphic variants in rs920778 and rs12826786 and PCa susceptibility. However, the CC genotype in rs12826786 was significantly associated with shorter biochemical recurrence-free survival in pT3-stage PCa patients. Conclusion: Our results indicate that HOTAIR rs12826786 CC genotype may be an independent prognostic biomarker in a particular subset of PCa tumors.

Carcinogenesis in prostate cancer: The role of long non-coding RNAs

LncRNAs appear to play a considerable role in tumourigenesis through regulating key processes in cancer cells such as proliferative signalling, replicative immortality, invasion and metastasis, evasion of growth suppressors, induction of angiogenesis and resistance to apoptosis. LncRNAs have been reported to play a role in prostate cancer, particularly in regulating the androgen receptor signalling pathway. In this review article, we summarise the role of 34 lncRNAs in prostate cancer with a particular focus on their role in the androgen receptor signalling pathway and the epithelial to mesenchymal transition pathway.

TR4 nuclear receptor suppresses HCC cell invasion via downregulating the EphA2 expression

Early studies indicated that testicular nuclear receptor 4 (TR4) could function as a suppressor in the transcriptional regulation of the HBV core gene expression, which might then influence the development of hepatocellular carcinoma (HCC). The direct linkage between TR4 and HCC progression, however, remained unclear. Here, via a human clinical sample survey, we found that 13 of the 18 HCC patients studied had lower TR4 expression in metastatic lesions than in matched primary HCC lesions, suggesting that TR4 may play a negative role in HCC metastasis. Results from in vitro cell migration/invasion studied confirmed that TR4 could suppress HCC cell migration/invasion. Mechanism dissection revealed that TR4 might function through downregulating ephrin type-A receptor 2 (EphA2) expression at the transcriptional level via direct binding to the TR4REs located on the 5' promoter of EphA2 to suppress HCC cell migration/invasion. Targeting the EphA2 via EphA2-siRNA partially reversed the enhanced HCC cell migration/invasion with confirmed TR4 knockdown. Notably, results from preclinical studies using in vivo mouse model with orthotopic xenograft of HCC LM3 cells also confirmed the in vitro findings. Taking these findings together, preclinical studies using multiple in vitro HCC cell lines and an in vivo mouse model all led to the conclusion that TR4 may function as a suppressor of HCC metastasis and that targeting this newly identified TR4-EphA2 signaling may improve our ability to suppress HCC metastasis.

Long non-coding RNA implicated in the invasion and metastasis of head and neck cancer: possible function and mechanisms

Head and neck cancer (HNC) ranks as the 6th most common malignancy across the world. Metastasis is a hallmark of cancer, primarily contributing to the relapse and poor prognosis of HNC. Recently, long noncoding RNAs (lncRNAs), previously considered as non-functional, are increasingly appreciated by scholars to play crucial roles in mediating HNC metastasis. LncRNAs, which are located in the nucleus and cytoplasm, mainly exert their function via epigenetic modification, transcriptional control and translational regulation. As several lncRNAs are presently demonstrated to participate in HNC metastasis, we make a summary of the functions and mechanisms regarding these lncRNAs. As shown in the literature, most lncRNAs appear to promote the metastasis of HNC. Hence, we primarily discuss the lncRNAs involved in enhancing metastasis. Additionally, more studies are needed to understand those lncRNAs without clear mechanisms. Furthermore, we introduced the upstream regulator for the aberrant expression of lncRNAs in HNC. Finally, we concisely addressed future research prospects of lncRNAs, particularly the interplay between lncRNAs and tumor immunity as well as lncRNA-targeted therapeutic techniques, and we introduced clustered regularly interspaced short palindromic repeats (CRISPR)-Display as a possibly transformative tool to study lncRNAs. Although lncRNA research is still in the initial stage, it holds great promise to be applied as a prognosticator of HNC and a therapeutic target to inhibit HNC metastasis, which could significantly enhance the outcome of HNC patients.

Androgen receptor (AR) degradation enhancer ASC-J9® in an FDA-approved formulated solution suppresses castration resistant prostate cancer cell growth

ASC-J9^® is a recently-developed androgen receptor (AR)-degradation enhancer that effectively suppresses castration resistant prostate cancer (PCa) cell proliferation and invasion. The optimal half maximum inhibitory concentrations (IC₅₀) of ASC-J9^® at various PCa cell confluences (20%, 50%, and 100%) were assessed via both short-term MTT growth assays and long-term clonogenic proliferation assays. Our results indicate that the IC₅₀ values for ASC-J9^® increased with increasing cell confluency. The IC₅₀ values were significantly decreased in PCa AR-positive cells compared to PCa AR-negative cells or in normal prostate cells. This suggests that ASC-J9^® may function mainly via targeting the AR-positive PCa cells with limited unwanted side-effects to suppress the surrounding normal prostate cells. Mechanism dissection indicated that ASC-J9^® might function via altering the apoptosis signals to suppress the PCa AR-negative PC-3 cells. Preclinical studies using multiple in vitro PCa cell lines and an in vivo mouse model with xenografted castration-resistant PCa CWR22Rv1 cells demonstrated that ASC-J9^® has similar AR degradation effects when dissolved in FDA-approved solvents, including DMSO, PEG-400:Tween-80 (95:5), DMA:Labrasol:Tween-80 (10:45:45), and DMA:Labrasol:Tween-20 (10:45:45). Together, results from preclinical studies suggest a potential new therapy with AR-degradation enhancer ASC-J9^® may potentially be ready to be used in human clinical trials in order to better suppress PCa at later castration resistant stages.

Infiltrating macrophages increase RCC epithelial mesenchymal transition (EMT) and stem cell-like populations via AKT and mTOR signaling

Infiltrating macrophages are a key component of inflammation during tumorigenesis and progression. However, the role of macrophages in renal cell carcinoma (RCC), especially in the stage of RCC malignant progression, is still unclear. Here, we found the macrophages could be recruited more easily into RCC tissues than the surrounding non-tumor tissues. In vitro co-culture system also confirmed RCC cells had a better capacity to recruit macrophages via CXCL8 signaling than normal renal epithelial cells. The consequences of recruiting more macrophages may then increase RCC cells invasion abilities. Mechanism dissection revealed that infiltrating macrophages could function through induction of epithelial-mesenchymal transition and increased cancer stem cell-like populations via activation of AKT/mTOR signal, and then led to increasing RCC cells invasion. The orthotopically xenografted mouse model with RCC cells and macrophages also confirmed that infiltrating macrophages could increase RCC cells progression via AKT/mTOR signal. Together, our results reveal a new mechanism that macrophages in the RCC tumor microenvironment could increase RCC metastasis via activation of the AKT/mTOR signals. Targeting this newly identified signaling may help us to better inhibit RCC metastasis.

Inflammatory Cytokine Signaling during Development of Pancreatic and Prostate Cancers

Inflammation is essential for many diseases including cancer. Activation and recruitment of immune cells during inflammation result in a cytokine- and chemokine-enriched cell environment, which affects cancer development. Since each type of cancer has its unique tumor environment, effects of cytokines from different sources such as tumor-infiltrating immune cells, stromal cells, endothelial cells, and cancer cells on cancer development can be quite complex. In this review, how immune cells contribute to tumorigenesis of pancreatic and prostate cancers through their secreted cytokines is discussed. In addition, the cytokine signaling that tumor cells of pancreatic and prostate cancers utilize to benefit their own survival is delineated.

Androgen-deprivation therapy with enzalutamide enhances prostate cancer metastasis via decreasing the EPHB6 suppressor expression

Early studies suggested that using ADT with the recently developed anti-androgen Enzalutamide (Enz, also named as MDV3100 could extent castration resistant prostate cancer (CRPC) patients' survival an extra 4.8 months. Yet the therapy in most patients might eventually fail due to development of Enz-resistance. Here we found Enz might also increase some unwanted side-effects via increasing the CRPC cell invasion that might involve altering the Enz-mediated androgen receptor (AR)/EPHB6 suppressor/JNK signaling. Results from multiple clinical surveys also indicated that EPHP6 might function as a suppressor of PCa metastasis. Mechanism dissection revealed that Enz-mediated AR might function via binding to the androgen-response-element (ARE) on the EPHB6 promoter to decrease EPHB6 suppressor expression, which might then activate the phosphorylation of JNK signals to increase the CRPC cell invasion. Targeting this newly identified AR/EPHB6/JNK signaling with JNK inhibitor (SP600125) may then block/reverse the Enz-increased CRPC cell invasion. Collectively, our results suggest that Enz may increase CRPC cell invasion via altering the AR/EPHB6/JNK/MMP9 signaling and targeting this newly identified signaling may help us to increase the Enz efficacy to better suppress the CRPC at the later metastatic stage.

Quantitative assessment of lncRNA HOTAIR polymorphisms and cancer risk in Chinese population: a meta-analysis based on 26,810 subjects

As a well-known long non-coding RNA, HOTAIR has been demonstrated to be involved in carcinogenesis and progression of various human cancers. Previous studies have investigated the potential association between HOTAIR polymorphisms and cancer risk in Chinese population. However, the results remain conflicting. Therefore, for the first time, we conducted a meta-analysis to derive a more precise estimation of these associations for Chinese. PubMed, Embase, CNKI and Wanfang databases were systematically searched. Odds ratios with 95% confidence intervals were applied to assess the association between rs920778, rs4759314, rs7958904, rs874945 and rs1899663 polymorphisms of HOTAIR and cancer susceptibility. Heterogeneity, sensitivity analysis and publication bias were conducted to measure the robustness of our findings. A total of 21 eligible studies comprising 12,278 cases and 14,532 controls were analyzed. The pooled data showed that rs920778 polymorphism was significantly associated with an increased cancer risk in all five genetic models in Chinese population. As for rs4759314 and rs874945 polymorphisms, similarly increased risks were found in specific genetic models and stratified groups. However, significant decreases in cancer risk were observed for rs7958904 in the total population, as well as in subgroup analyses. In addition, lack of association was detected between rs1899663 polymorphism and cancer susceptibility. In summary, our meta-analysis implicates possible relationship between HOTAIR polymorphisms and cancer risk in Chinese population.

Cellular determinants and microenvironmental regulation of prostate cancer metastasis

Metastasis causes more than 90% of cancer-related deaths and most prostate cancer (PCa) patients also die from metastasis. The 'metastatic cascade' is a complex biological process that encompasses tumor cell dissociation (from the primary tumor), local invasion, intravasation, transport in circulation, extravasation, colonization, and overt growth in end organs. It has become clear that successful metastasis not only involves many tumor cell-intrinsic properties but also depends on productive interactions between cancer cells and the tumor microenvironment. In this Review, we begin with a general summary on cancer metastasis and a specific discussion on PCa metastasis. We then discuss recent advances in our knowledge of the cellular determinants of PCa metastasis and the importance of tumor microenvironment, especially an immunosuppressive tumor microenvironment, in shaping metastatic propensities. We conclude with a presentation of current and future therapeutic options for patients with PCa metastasis, emphasizing the development of novel, mechanism-based combinatorial strategies for treating metastatic and castration-resistant PCa.

Are Mast Cells MASTers in Cancer?

Prolonged low-grade inflammation or smoldering inflammation is a hallmark of cancer. Mast cells form a heterogeneous population of immune cells with differences in their ultra-structure, morphology, mediator content, and surface receptors. Mast cells are widely distributed throughout all tissues and are stromal components of the inflammatory microenvironment that modulates tumor initiation and development. Although canonically associated with allergic disorders, mast cells are a major source of pro-tumorigenic (e.g., angiogenic and lymphangiogenic factors) and antitumorigenic molecules (e.g., TNF-α and IL-9), depending on the milieu. In certain neoplasias (e.g., gastric, thyroid and Hodgkin's lymphoma) mast cells play a pro-tumorigenic role, in others (e.g., breast cancer) a protective role, whereas in yet others they are apparently innocent bystanders. These seemingly conflicting results suggest that the role of mast cells and their mediators could be cancer specific. The microlocalization (e.g., peritumoral vs intratumoral) of mast cells is another important aspect in the initiation/progression of solid and hematologic tumors. Increasing evidence in certain experimental models indicates that targeting mast cells and/or their mediators represent a potential therapeutic target in cancer. Thus, mast cells deserve focused consideration also as therapeutic targets in different types of tumors. There are many unanswered questions that should be addressed before we understand whether mast cells are an ally, adversary, or innocent bystanders in human cancers.

Natural killer cells suppress enzalutamide resistance and cell invasion in the castration resistant prostate cancer via targeting the androgen receptor splicing variant 7 (ARv7)

Despite the success of androgen-deprivation therapy (ADT) with the newly developed anti-androgen enzalutamide (Enz, also known as MDV3100) to suppress castration resistant prostate cancer (CRPC) in extending patient survival by an extra 4.8 months, eventually patients die with the development of Enz resistance that may involve the induction of the androgen receptor (AR) splicing variant ARv7. Here we identify an unrecognized role of Natural Killer (NK) cells in the prostate tumor microenvironment that can be better recruited to the CRPC cells to suppress ARv7 expression resulting in suppressing the Enz resistant CRPC cell growth and invasion. Mechanism dissection revealed that CRPC cells, compared to normal prostate epithelial cells, could recruit more NK cells that might then lead to alterations of the microRNA-34 and microRNA-449 to suppress both ARv7 expression and ARv7-induced EZH2 expression to suppress CRPC cell invasion. Together, these results identify a new potential therapy using recruited NK cells to better suppress the Enz resistance and cell invasion in CRPC at the later enzalutamide resistant stage.

Prostate Cancer Stem Cells and Nanotechnology: A Focus on Wnt Signaling

Prostate cancer is the most common cancer among men worldwide. However, current treatments for prostate cancer patients in advanced stage often fail because of relapse. Prostate cancer stem cells (PCSCs) are resistant to most standard therapies, and are considered to be a major mechanism of cancer metastasis and recurrence. In this review, we summarized current understanding of PCSCs and their self-renewal signaling pathways with a specific focus on Wnt signaling. Although multiple Wnt inhibitors have been developed to target PCSCs, their application is still limited by inefficient delivery and toxicity in vivo. Recently, nanotechnology has opened a new avenue for cancer drug delivery, which significantly increases specificity and reduces toxicity. These nanotechnology-based drug delivery methods showed great potential in targeting PCSCs. Here, we summarized current advancement of nanotechnology-based therapeutic strategies for targeting PCSCs and highlighted the challenges and perspectives in designing future therapies to eliminate PCSCs.

Androgen Receptor Regulates the Growth of Neuroblastoma Cells in vitro and in vivo

Background: Neuroblastoma is the most common extracranial tumors in children. At present about the true etiology of neuroblastoma is unclear and many studies have tried to find effective treatments for these primary malignant tumors. Although it has been illustrated that androgen receptor (AR) was expressed in neuroblastoma cells in some former reports, the biological role of androgen receptor in the development of neuroblastoma is not fully understood.

Methods: Androgen (R1881) and the antagonists of androgen receptor (MDV3100 and ARN509) were used to study the role of the androgen receptor signaling pathway in vitro and in vivo on SH-SY5Y and Neuro-2a (N2a) cell lines.

Results: We found that AR expression showed an R1881 dose-dependent manner in neuroblastoma cells in vitro and R1881was able to increase, while both antagonists of androgen receptor (MDV3100 and ARN509) significantly decrease, the proliferation, migration, invasion and sphere formation of SH-SY5Y and N2a cells. Moreover, androgen promoted the growth of N2a tumor in vivo. However, when androgen receptor (AR) was effectively knocked down in the two cell lines by siRNA, either promoting or inhibiting effect of the androgen or androgen receptor antagonists, respectively, was attenuated.

Conclusion: Our results suggested that androgen receptor may involve in the progression of neuroblastoma as well as provided insight into a new target for the diagnosis and treatment of neuroblastoma patients.

Uncovering the roles of long non-coding RNAs in cancer stem cells

Cancer has been a major public health problem that has threatened human life worldwide throughout history. The main causes that contribute to the poor prognosis of cancer are metastasis and recurrence. Cancer stem cells are a group of tumor cells that possess self-renewal and differentiation ability, which is a vital cause of cancer metastasis and recurrence. Long non-coding RNAs refer to a class of RNAs that are longer than 200 nt and have no potential to code proteins, some of which can be specifically expressed in different tissues and different tumors. Long non-coding RNAs have great biological significance in the occurrence and progression of cancers. However, how long non-coding RNAs interact with cancer stem cells and then affect cancer metastasis and recurrence is not yet clear. Therefore, this review aims to summarize recent studies that focus on how long non-coding RNAs impact tumor occurrence and progression by affecting cancer stem cell self-renewal and differentiation in liver cancer, prostate cancer, breast cancer, and glioma.

Cancer Stem Cells and Their Microenvironment: Biology and Therapeutic Implications

Tumor consists of heterogeneous cancer cells including cancer stem cells (CSCs) that can terminally differentiate into tumor bulk. Normal stem cells in normal organs regulate self-renewal within a stem cell niche. Likewise, accumulating evidence has also suggested that CSCs are maintained extrinsically within the tumor microenvironment, which includes both cellular and physical factors. Here, we review the significance of stromal cells, immune cells, extracellular matrix, tumor stiffness, and hypoxia in regulation of CSC plasticity and therapeutic resistance. With a better understanding of how CSC interacts with its niche, we are able to identify potential therapeutic targets for the development of more effective treatments against cancer.

Infiltrating mast cells promote renal cell carcinoma angiogenesis by modulating PI3K→︀AKT→︀GSK3β→︀AM signaling

The recruitment of vascular endothelial cells from the tumor microenvironment (TME) to promote angiogenesis plays key roles in the progression of renal cell carcinoma (RCC). The potential impact of immune cells in the TME on RCC angiogenesis, however, remains unclear. Here, we found that recruitment of mast cells resulted in increased RCC angiogenesis in both in vitro cell lines and in vivo mouse models. Mechanistic analyses revealed that RCC recruited mast cells by modulating PI3K→AKT→GSK3β→AM signaling. A clinical survey of human RCC samples also showed that higher expression of the PI3K→AKT→GSK3β→AM signaling pathway correlated with increased angiogenesis. Interruption of PI3K→AKT→GSK3β→AM signaling via specific inhibitors led to decreased recruitment of mast cells, and targeting this infiltrating mast cell-related signaling via an AKT-specific inhibitor suppressed RCC angiogenesis in xenograft mouse models. Together, these results identified a novel role of infiltrating mast cells in RCC angiogenesis and metastasis and suggest a new strategy for treating RCC by targeting this newly identified signaling pathway.

Infiltrating mast cells increase prostate cancer chemotherapy and radiotherapy resistances via modulation of p38/p53/p21 and ATM signals

Early studies indicated that mast cells in prostate tumor microenvironment might influence prostate cancer (PCa) progression. Their impacts to PCa therapy, however, remained unclear. Here we found PCa could recruit more mast cells than normal prostate epithelial cells then alter PCa chemotherapy and radiotherapy sensitivity, leading to PCa more resistant to these therapies. Mechanism dissection revealed that infiltrated mast cells could increase p21 expression via modulation of p38/p53 signals, and interrupting p38-p53 signals via siRNAs of p53 or p21 could reverse mast cell-induced docetaxel chemotherapy resistance of PCa. Furthermore, recruited mast cells could also increase the phosphorylation of ATM at ser-1981 site, and inhibition of ATM activity could reverse mast cell-induced radiotherapy resistance. The in vivo mouse model with xenografted PCa C4-2 cells co-cultured with mast cells also confirmed that mast cells could increase PCa chemotherapy resistance via activating p38/p53/p21 signaling. Together, our results provide a new mechanism showing infiltrated mast cells could alter PCa chemotherapy and radiotherapy sensitivity via modulating the p38/p53/p21 signaling and phosphorylation of ATM. Targeting this newly identified signaling may help us better suppress PCa chemotherapy and radiotherapy resistance.