Over-expression of TRPM8 is associated with poor prognosis in urothelial carcinoma of bladder

Association of higher transient receptor potential melastatin 8 expression with higher tumor histologic grades, lymph node metastasis, risk factors, and worse survival in patients with head and neck squamous cell carcinoma

Background/purpose

Transient receptor potential melastatin 8 (TRPM8), a thermosensitive ion channel known for its role in cold sensation and menthol response, has emerged as a potential regulator in various cancers. This study aimed to investigate expression trends of TRPM8 in head and neck squamous cell carcinoma (HNSCC) cases and oral squamous cell carcinoma (OSCC) cell lines and its association with clinicopathological features.

Materials and methods

The noncancerous matched tissues and HNSCC paired tissue samples from 84 HNSCC patients were utilized to evaluate the association of TRPM8 with HNSCC clinicopathological features. TRPM8 expression was examined in HNSCC patient tissues and OSCC cell lines treated with arecoline.

Results

Kaplan-Meier survival analysis of TCGA data revealed high TRPM8 expression correlated with unfavorable outcomes and higher tumor histologic grades. TRPM8 mRNA expression was upregulated in HNSCC cell lines and patients' tissue samples. Arecoline treatment led to significantly increased TRPM8 mRNA and protein expression in OSCC cell lines. Lymph node metastasis showed a significant association with upregulated TRPM8 expression in combined OSCC and oropharyngeal squamous cell carcinoma (OPSCC) cases. TRPM8 mRNA expression was upregulated in HNSCC and OSCC patients with alcohol drinking and cigarette smoking habits, but not in betel quid chewing.

Conclusion

These findings reveal the involvement of TRPM8 in HNSCC's malignant development and metastasis, suggesting that high expression of TRMP8 may be mutually causal with addiction to tobacco, alcohol, and betel nut in HNSCC patients. Further investigations are needed to determine the underlying pathways of TRPM8 in HNSCC's development and progression.

TRP Channels in Cancer: Signaling Mechanisms and Translational Approaches

Ion channels play a crucial role in a wide range of biological processes, including cell cycle regulation and cancer progression. In particular, the transient receptor potential (TRP) family of channels has emerged as a promising therapeutic target due to its involvement in several stages of cancer development and dissemination. TRP channels are expressed in a large variety of cells and tissues, and by increasing cation intracellular concentration, they monitor mechanical, thermal, and chemical stimuli under physiological and pathological conditions. Some members of the TRP superfamily, namely vanilloid (TRPV), canonical (TRPC), melastatin (TRPM), and ankyrin (TRPA), have been investigated in different types of cancer, including breast, prostate, lung, and colorectal cancer. TRP channels are involved in processes such as cell proliferation, migration, invasion, angiogenesis, and drug resistance, all related to cancer progression. Some TRP channels have been mechanistically associated with the signaling of cancer pain. Understanding the cellular and molecular mechanisms by which TRP channels influence cancer provides new opportunities for the development of targeted therapeutic strategies. Selective inhibitors of TRP channels are under initial scrutiny in experimental animals as potential anti-cancer agents. In-depth knowledge of these channels and their regulatory mechanisms may lead to new therapeutic strategies for cancer treatment, providing new perspectives for the development of effective targeted therapies.

Construction of a prediction model for prognosis of bladder cancer based on the expression of ion channel-related genes

OBJECTIVES

To construct a prediction model for the prognosis of bladder cancer patients based on the expression of ion channel-related genes (ICRGs).

METHODS

ICRGs were obtained from the existing researches. The clinical information and the expression of ICRGs mRNA in breast cancer patients were obtained from the Cancer Genome Atlas database. Cox regression analysis, minimum absolute shrinkage and selection operator regression analysis were used to screen breast cancer prognosis related genes, which were verified by immunohistochemistry and qRT-PCR. The risk scoring equation for predicting the prognosis of patients with bladder cancer was constructed, and the patients were divided into high-risk group and low-risk group according to the median risk score. Immune cell infiltration was compared between the two groups. Kaplan-Meier survival curve and receiver operating characteristic (ROC) curve were used to evaluate the accuracy and clinical application value of the risk scoring equation. The factors related to the prognosis of bladder cancer patients were analyzed by univariate and multivariate Cox regression, and a nomogram for predicting the prognosis of bladder cancer patients was constructed.

RESULTS

By comparing the expression levels of ICRGs in bladder cancer tissues and normal bladder tissues, 73 differentially expressed ICRGs were dentified, of which 11 were related to the prognosis of bladder cancer patients. Kaplan-Meier survival curve suggested that the risk score based on these 11 genes was negatively correlated with the prognosis of patients. The area under the ROC curve of the risk score for predicting the prognosis of patients at 1, 3 and 5 year was 0.634, 0.665 and 0.712, respectively. Stratified analysis showed that the ICRGs-based risk score performed well in predicting the prognosis of patients with American Joint Committee on Cancer (AJCC) stage Ⅲ-Ⅳ bladder cancer (P<0.05), while it had a poor value in predicting the prognosis of patients with AJCC stage Ⅰ-Ⅱ (P>0.05). There were significant differences in the infiltration of plasma cells, activated natural killer cells, resting mast cells and M2 macrophages between the high-risk group and the low-risk group. Cox regression analysis showed that risk score, smoking, age and AJCC stage were independently associated with the prognosis of patients with bladder cancer (P<0.05). The nomogram constructed by combining risk score and clinical parameters has high accuracy in predicting the 1, 3 and 5 year overall survival rate of bladder cancer patients.

CONCLUSIONS

The study shows the potential value of ICRGs in the prognostic risk assessment of bladder cancer patients. The constructed prognostic nomogram based on ICRGs risk score has high accuracy in predicting the prognosis of bladder cancer patients.

"ThermoTRP" Channel Expression in Cancers: Implications for Diagnosis and Prognosis (Practical Approach by a Pathologist)

Temperature-sensitive transient receptor potential (TRP) channels (so-called "thermoTRPs") are multifunctional signaling molecules with important roles in cell growth and differentiation. Several "thermoTRP" channels show altered expression in cancers, though it is unclear if this is a cause or consequence of the disease. Regardless of the underlying pathology, this altered expression may potentially be used for cancer diagnosis and prognostication. "ThermoTRP" expression may distinguish between benign and malignant lesions. For example, TRPV1 is expressed in benign gastric mucosa, but is absent in gastric adenocarcinoma. TRPV1 is also expressed both in normal urothelia and non-invasive papillary urothelial carcinoma, but no TRPV1 expression has been seen in invasive urothelial carcinoma. "ThermoTRP" expression can also be used to predict clinical outcomes. For instance, in prostate cancer, TRPM8 expression predicts aggressive behavior with early metastatic disease. Furthermore, TRPV1 expression can dissect a subset of pulmonary adenocarcinoma patients with bad prognosis and resistance to a number of commonly used chemotherapeutic agents. This review will explore the current state of this rapidly evolving field with special emphasis on immunostains that can already be added to the armoire of diagnostic pathologists.

Therapeutic potential of TRPM8 channels in cancer treatment

Cancer is a multifactorial process associated with changes in signaling pathways leading to cell cycle variations and gene expression. The transient receptor potential melastatin 8 (TRPM8) channel is a non-selective cation channel expressed in neuronal and non-neuronal tissues, where it is involved in several processes, including thermosensation, differentiation, and migration. Cancer is a multifactorial process associated with changes in signaling pathways leading to variations in cell cycle and gene expression. Interestingly, it has been shown that TRPM8 channels also participate in physiological processes related to cancer, such as proliferation, survival, and invasion. For instance, TRPM8 channels have an important role in the diagnosis, prognosis, and treatment of prostate cancer. In addition, it has been reported that TRPM8 channels are involved in the progress of pancreatic, breast, bladder, colon, gastric, and skin cancers, glioblastoma, and neuroblastoma. In this review, we summarize the current knowledge on the role of TRPM8 channels in cancer progression. We also discuss the therapeutic potential of TRPM8 in carcinogenesis, which has been proposed as a molecular target for cancer therapy.

Transcriptional landscape of TRPV1, TRPA1, TRPV4, and TRPM8 channels throughout human tissues

AIMS

This article aims to analyze the baseline distribution of TRPA1, TRPV1, TRPV4, and TRPM8 channels in human systems at the transcriptional level.

MAIN METHODS

Using the RNA-seq dataset from the National Center for Biotechnology Information (NCBI) gene database, we investigated and compared the transcriptional levels of TRPV1, TRPA1, TRPV4 and TRPM8 found in 95 human subjects representing 33 different tissues to determine the tissue specificity of all protein-coding genes.

KEY FINDING

In this study, we observed higher transcriptional levels for TRPV1 (duodenum), TRPA1 (Urinary bladder), TRPV4 (Kidney) and TRPM8 (Prostate) compared to the other TRPs.

SIGNIFICANCE

These channels are involved in developing inflammatory and painful pathologies and seem to participate in cancer development. This information on transcriptional levels of TRPV1, TRPA1, TRPV4 and TRPM8 in human systems may provide essential suggestions for further studies on these proteins.

Expression of transient receptor potential cation channel subfamily M member 8 in gastric cancer and its clinical significance

Transient receptor potential cation channel subfamily M member (TRPM8) is abnormally expressed in many malignant tumors, such as breast cancer and pancreatic cancer, but its expression in gastric cancer (GC) has remained unclear. The present study aimed to detect TRPM8 expression and to explore its clinical significance in GC. Western blotting and immunohistochemistry were used to detect the protein expression of TRPM8 in 134 pairs of GC and adjacent healthy tissues. The association of TRMP8 with the 5-year overall survival rate of patients with GC was assessed using a Cox regression model. TRPM8 protein expression was significantly elevated (P<0.05) in gastric tumor cells (SUN-1, AGS, SNU-5 and NCI-N87) and was significantly associated with tumor diameter (P=0.003), Tumor-Node-Metastasis stage (P=0.003), lymph node metastasis (P=0.001) and cancer cell remote metastasis (P=0.010) in patients with GC. The expression of TRPM8 protein was significantly higher in GC patients with a tumor diameter of ≥2.5 cm. Additionally, TRPM8 protein expression in patients with metastases was significantly higher compared with patients without metastasis. Cox regression analysis revealed that TRPM8 protein expression was an independent risk factor for prognosis (odds ratio, 1.625; 95% CI=0.552-3.128) in patients with GC. In addition, the 5-year overall survival rate of patients with high expression of TRPM8 protein (64.44%) in GC was significantly lower compared with patients with low expression (12.36%). TRPM8 was highly expressed in GC tissues and may promote GC cell proliferation and metastasis in vivo.

TRP Channels and Small GTPases Interplay in the Main Hallmarks of Metastatic Cancer

Transient Receptor Potential (TRP) cations channels, as key regulators of intracellular calcium homeostasis, play a central role in the essential hallmarks of cancer. Among the multiple pathways in which TRPs may be involved, here we focus our attention on the ones involving small guanosine triphosphatases (GTPases), summarizing the main processes associated with the metastatic cascade, such as migration, invasion and tumor vascularization. In the last decade, several studies have highlighted a bidirectional interplay between TRPs and small GTPases in cancer progression: TRP channels may affect small GTPases activity via both Ca²⁺-dependent or Ca²⁺-independent pathways, and, conversely, some small GTPases may affect TRP channels activity through the regulation of their intracellular trafficking to the plasma membrane or acting directly on channel gating. In particular, we will describe the interplay between TRPC1, TRPC5, TRPC6, TRPM4, TRPM7 or TRPV4, and Rho-like GTPases in regulating cell migration, the cooperation of TRPM2 and TRPV2 with Rho GTPases in increasing cell invasiveness and finally, the crosstalk between TRPC1, TRPC6, TRPM8, TRPV4 and both Rho- and Ras-like GTPases in inducing aberrant tumor vascularization.

TRPM8 Inhibition Regulates the Proliferation, Migration and ROS Metabolism of Bladder Cancer Cells

Introduction

Based on accumulating evidence, transient receptor potential (TRP) ion channels may play important roles in the occurrence and the progression of cancer. TRP melastatin 8 (TRPM8), a member of the TRP family, functions as a Ca²⁺-permeable channel and regulates various physiological and pathological processes. However, the effects of TRPM8 on bladder cancer (BCa) and its underlying mechanisms have not been elucidated.

Methods

BCa tissues and matched noncancerous tissues were collected to examine the expression of the TRPM8 mRNA and protein using qRT-PCR, Western blotting and immunofluorescence staining. Meanwhile, the effect of knockdown or inhibition of the activity of the TRPM8 protein on the proliferation, migration and ROS metabolism of bladder cancer cells was detected using the MTT assay, clonogenic survival assay, Transwell chamber migration assay, and reactive oxygen species (ROS) detection, respectively. Furthermore, a mouse model transplanted with BCa cells was established to assess tumor growth after TRPM8 expression was inhibited in vivo.

Results

Compared with the noncancerous tissues, the levels of TRPM8 in BCa tissues were significantly increased. Knockdown or inhibition of the activity of the TRPM8 protein in BCa cells reduced cell proliferation and migration. Moreover, the production of ROS was increased in cells treated with siTRPM8, which was accompanied by increased levels of Catalase, HO-1 and SOD2. Furthermore, a mouse model transplanted with the stable TRPM8-deficient T24 cell line was established, demonstrating that knockdown of TRPM8 delayed tumor growth in vivo.

Discussion

TRPM8 might play an essential for BCa tumor progression and metastasis by interfering with BCa cell proliferation, motility, ROS metabolism and migration.

Highly functionalized β-lactams and 2-ketopiperazines as TRPM8 antagonists with antiallodynic activity

The cool sensor transient receptor potential melastatin channel 8 (TRPM8) is highly expressed in trigeminal and dorsal root ganglia, playing a key role in cold hypersensitivity associated to different peripheral neuropathies. Moreover, these channels are aberrantly expressed in different cancers, and seem to participate in tumor progression, survival and invasion. Accordingly, the search for potent and selective TRPM8 modulators attracted great interest in recent years. We describe new heterocyclic TRPM8 antagonist chemotypes derived from N-cloroalkyl phenylalaninol-Phe conjugates. The cyclization of these conjugates afforded highly substituted β-lactams and/or 2-ketopiperazine (KP) derivatives, with regioselectivity depending on the N-chloroalkyl group and the configuration. These derivatives behave as TRPM8 antagonists in the Ca2+ microfluorometry assay, and confirmed electrophysiologically for the best enantiopure β-lactams 24a and 29a (IC50, 1.4 and 0.8 µM). Two putative binding sites by the pore zone, different from those found for typical agonists and antagonists, were identified by in silico studies for both β-lactams and KPs. β-Lactams 24a and 29a display antitumor activity in different human tumor cell lines (micromolar potencies, A549, HT29, PSN1), but correlation with TRPM8 expression could not be established. Additionally, compound 24a significantly reduced cold allodynia in a mice model of oxaliplatin-induced peripheral neuropathy.

TRPM8 channels: A review of distribution and clinical role

Ion channels are important therapeutic targets due to their plethoric involvement in physiological and pathological consequences. The transient receptor potential cation channel subfamily M member 8 (TRPM8) is a nonselective cation channel that controls Ca²⁺ homeostasis. It has been proposed to be the predominant thermoreceptor for cellular and behavioral responses to cold stimuli in the transient receptor potential (TRP) channel subfamilies and exploited so far to reach the clinical-stage of drug development. TRPM8 channels can be found in multiple organs and tissues, regulating several important processes such as cell proliferation, migration and apoptosis, inflammatory reactions, immunomodulatory effects, pain, and vascular muscle tension. The related disorders have been expanded to new fields ranging from cancer and migraine to dry eye disease, pruritus, irritable bowel syndrome (IBS), and chronic cough. This review is aimed to summarize the distribution of TRPM8 and disorders related to it from a clinical perspective, so as to broaden the scope of knowledge of researchers to conduct more studies on this subject.

Silencing of TRPM8 inhibits aggressive tumor phenotypes and enhances gemcitabine sensitivity in pancreatic cancer

The transient receptor potential TRPM8 ion channel is required for cellular proliferation in pancreatic epithelia and adenocarcinoma. To elucidate the mechanism that mediates the function of TRPM8, we examined its role in the proliferation and invasion of pancreatic cancer (PC) cells. TRPM8 expression increased in both the PC tissues and cell lines; a high TRPM8 expression was correlated with poorer prognosis in patients with PC. In PC cell lines, PACN-1 and BxPC-3, Ca²⁺ influxes could be evoked by TRPM8; the sensitivity of PC cells to gemcitabine was increased, while the proliferation and invasion of PC cells were suppressed after RNA interference-mediated silencing of TRPM8. The mechanism of TRPM8 in gemcitabine-based chemotherapy was then investigated. The expression and activity of multidrug resistance-associated proteins, P-gp, MRP-2, LRP, was significantly reduced in response to TRPM8 silence. Moreover, TRPM8 knockdown significantly increased hENT1 protein levels and the ratio of Bax/Bcl-2 while decreased the protein levels of RRM1. Thus, TRPM8 is required for PC cell proliferation and invasion and was closely related to the gemcitabine sensitivity of PC. The modulation of TRPM8 expression may help improve treatment response of PC by combining with traditional chemotherapy.

Elevated Transient Receptor Potential Melastatin 8 (TRPM8) Expression Is Correlated with Poor Prognosis in Pancreatic Cancer

BACKGROUND The transient receptor potential melastatin 8 (TRPM8) was found to be expressed abnormally in a variety of tumors and is associated with unfavorable prognosis in human cancers. However, its clinical significance in pancreatic cancer (PC) is mostly unknown. MATERIAL AND METHODS qRT-PCR was performed to measure the expression of TRPM8 in 110 pairs of PC tissues and the adjacent non-cancerous tissues. The association of TRPM8 expression with the clinical characters of PC patients was analyzed using the chi-square test. Furthermore, the prognostic value of TRPM8 was determined with Kaplan-Meier survival curve and Cox regression analysis. RESULTS We found that the expression level of TRPM8 was significantly elevated in PC tissues compared to the non-cancerous controls (P<0.001). In addition, a close relationship was observed between elevated TRPM8 expression with large tumor size (P=0.001), advanced TNM (P=0.013), and distant metastasis (P=0.034). Survival analysis suggested that patients with high TRPM8 expression has worse OS (P=0.001) and DFS (P<0.001) than those with low TRPM8 expression. Moreover, TRPM8 was confirmed as a valuable prognostic biomarker for OS (HR=1.913; 95% CI: 1.020-3.589; P=0.043) or DFS (HR=2.374; 95% CI: 1.269-4.443; P=0.007) of PC patients. CONCLUSIONS This study shows that TRPM8 expression is significantly up-regulated in PC and it might be a useful prognostic factor for patients with PC.

The Role of TRP Channels in the Metastatic Cascade

A dysregulated cellular Ca2+ homeostasis is involved in multiple pathologies including cancer. Changes in Ca2+ signaling caused by altered fluxes through ion channels and transporters (the transportome) are involved in all steps of the metastatic cascade. Cancer cells thereby "re-program" and "misuse" the cellular transportome to regulate proliferation, apoptosis, metabolism, growth factor signaling, migration and invasion. Cancer cells use their transportome to cope with diverse environmental challenges during the metastatic cascade, like hypoxic, acidic and mechanical cues. Hence, ion channels and transporters are key modulators of cancer progression. This review focuses on the role of transient receptor potential (TRP) channels in the metastatic cascade. After briefly introducing the role of the transportome in cancer, we discuss TRP channel functions in cancer cell migration. We highlight the role of TRP channels in sensing and transmitting cues from the tumor microenvironment and discuss their role in cancer cell invasion. We identify open questions concerning the role of TRP channels in circulating tumor cells and in the processes of intra- and extravasation of tumor cells. We emphasize the importance of TRP channels in different steps of cancer metastasis and propose cancer-specific TRP channel blockade as a therapeutic option in cancer treatment.

Menthol evokes Ca2+ signals and induces oxidative stress independently of the presence of TRPM8 (menthol) receptor in cancer cells

Menthol is a naturally occurring monoterpene alcohol possessing remarkable biological properties including antipruritic, analgesic, antiseptic, anti-inflammatory and cooling effects. Here, we examined the menthol-evoked Ca²⁺ signals in breast and prostate cancer cell lines. The effect of menthol (50–500 µM) was predicted to be mediated by the transient receptor potential ion channel melastatin subtype 8 (TRPM8). However, the intensity of menthol-evoked Ca²⁺ signals did not correlate with the expression levels of TRPM8 in breast and prostate cancer cells indicating a TRPM8-independent signaling pathway. Menthol-evoked Ca²⁺ signals were analyzed in detail in Du 145 prostate cancer cells, as well as in CRISPR/Cas9 TRPM8-knockout Du 145 cells. Menthol (500 µM) induced Ca²⁺ oscillations in both cell lines, thus independent of TRPM8, which were however dependent on the production of inositol trisphosphate. Results based on pharmacological tools point to an involvement of the purinergic pathway in menthol-evoked Ca²⁺ responses. Finally, menthol (50–500 µM) decreased cell viability and induced oxidative stress independently of the presence of TRPM8 channels, despite that temperature-evoked TRPM8-mediated inward currents were significantly decreased in TRPM8-knockout Du 145 cells compared to wild type Du 145 cells.

TRPM8 is required for survival and radioresistance of glioblastoma cells

TRPM8 is a Ca²⁺-permeable nonselective cation channel belonging to the melastatin sub-group of the transient receptor potential (TRP) family. TRPM8 is aberrantly overexpressed in a variety of tumor entities including glioblastoma multiforme where it reportedly contributes to tumor invasion. The present study aimed to disclose further functions of TRPM8 in glioma biology in particular upon cell injury by ionizing radiation. To this end, TCGA data base was queried to expose the TRPM8 mRNA abundance in human glioblastoma specimens and immunoblotting was performed to analyze the TRPM8 protein abundance in primary cultures of human glioblastoma. Moreover, human glioblastoma cell lines were irradiated with 6 MV photons and TRPM8 channels were targeted pharmacologically or by RNA interference. TRPM8 abundance, Ca²⁺ signaling and resulting K⁺ channel activity, chemotaxis, cell migration, clonogenic survival, DNA repair, apoptotic cell death, and cell cycle control were determined by qRT-PCR, fura-2 Ca²⁺ imaging, patch-clamp recording, transfilter migration assay, wound healing assay, colony formation assay, immunohistology, flow cytometry, and immunoblotting. As a result, human glioblastoma upregulates TRPM8 channels to variable extent. TRPM8 inhibition or knockdown slowed down cell migration and chemotaxis, attenuated DNA repair and clonogenic survival, triggered apoptotic cell death, impaired cell cycle and radiosensitized glioblastoma cells. Mechanistically, ionizing radiation activated and upregulated TRPM8-mediated Ca²⁺ signaling that interfered with cell cycle control probably via CaMKII, cdc25C and cdc2. Combined, our data suggest that TRPM8 channels contribute to spreading, survival and radioresistance of human glioblastoma and, therefore, might represent a promising target in future anti-glioblastoma therapy.

Potential role of melastatin-related transient receptor potential cation channel subfamily M gene expression in the pathogenesis of urinary bladder cancer

Urinary bladder cancer is one of the most common malignancies of the urinary tract. Ion channels and calcium homeostasis are involved in almost all basic cellular mechanisms. The transient receptor potential cation channel subfamily M (TRPM) takes its name from the melastatin protein, which is classified as potential tumor suppressor. To the best of our knowledge, there have been no previous studies in the literature investigating the role of these ion channels in bladder cancer. The present study aimed to determine whether bladder cancer is associated with mRNA expression levels of TRPM ion channel genes, and whether there is the potential to conduct further studies to establish novel treatment modalities. The present study included a total of 47 subjects, of whom 40 were bladder cancer patients and 7 were controls. Following the histopathological evaluation for bladder carcinoma, the mRNA and protein expression of TRPM were examined by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry in tumor and normal tissues, in order to determine whether there is a difference in the expression of these channels in tumor and normal tissues. Immunoreactivity for TRPM2, TRPM4, TRPM7 and TRPM8 was observed in epithelial bladder cells in the two groups. RT-qPCR revealed a significant increase in TRPM7 expression in bladder cancer tissue compared to the controls (healthy bladder tissue), whereas no differences in TRPM2 or TRPM4 expression levels were observed. There were significant reductions in the expression levels of TRPM5 and TRPM8 in bladder cancer tissues. In the present study, the effects of TRP ion channels on the formation of bladder cancer was investigated. This study is instructive for TRPM2, TRPM4, TRPM5, TRPM7 and TRPM8 and their therapeutic role in bladder cancer. The results support the fact that these gens can be novel targets and can also be tested for during the treatment of bladder cancer.

Sphingosine kinase 1 is a reliable prognostic factor and a novel therapeutic target for uterine cervical cancer

Sphingosine kinase 1 (SPHK1), an oncogenic kinase, has previously been found to be upregulated in various types of human malignancy and to play a crucial role in tumor development and progression. Although SPHK1 has gained increasing prominence as an important enzyme in cancer biology, its potential as a predictive biomarker and a therapeutic target in cervical cancer remains unknown. SPHK1 expression was examined in 287 formalin-fixed, paraffin-embedded cervical cancer tissues using immunohistochemistry, and its clinical implications and prognostic significance were analyzed. Cervical cancer cell lines including HeLa and SiHa were treated with the SPHK inhibitors SKI-II or FTY720, and effects on cell survival, apoptosis, angiogenesis, and invasion were examined. Moreover, the effects of FTY720 on tumor growth were evaluated using a patient-derived xenograft (PDX) model of cervical cancer. Immunohistochemical analysis revealed that expression of SPHK1 was significantly increased in cervical cancer compared with normal tissues. SPHK1 expression was significantly associated with tumor size, invasion depth, FIGO stage, lymph node metastasis, and lymphovascular invasion. Patients with high SPHK1 expression had lower overall survival and recurrence-free survival rates than those with low expression. Treatment with SPHK inhibitors significantly reduced viability and increased apoptosis in cervical cancer cells. Furthermore, FTY720 significantly decreased in vivo tumor weight in the PDX model of cervical cancer. We provide the first convincing evidence that SPHK1 is involved in tumor development and progression of cervical cancer. Our data suggest that SPHK1 might be a potential prognostic marker and therapeutic target for the treatment of cervical cancer.

High expression of TRPM8 predicts poor prognosis in patients with osteosarcoma

The transient receptor potential melastatin member 8 (TRPM8) is a newly characterized oncoprotein involved in various malignant tumors. However, its expression pattern and biological function in osteosarcoma remain unclear. The present study aimed to explore the expression and prognostic significance of TRPM8 in osteosarcoma (OS). The results revealed that the expression of TRPM8 mRNA and protein in OS tissue was significantly higher than that in paired normal bone tissue (P<0.05). Additionally, the level of TRPM8 mRNA and protein in patients with a higher clinical stage and with distant metastasis was markedly higher than in those with a lower clinical stage and no metastasis (P<0.05). Furthermore, a high TRPM8 level was closely associated with clinical stage and distant metastasis (P=0.007 and 0.030), but not associated with the patient age (P=0.481), gender (P=0.905), tumor size (P=0.429), histological subtype (P=0.207) or anatomical location (P=0.369). In addition, OS patients with high TRPM8 expression had significantly shorter overall survival (P=0.008) and disease-free survival times (P=0.008) when compared with patients with low expression of TRPM8. In Cox multivariate analysis, TRPM8 overexpression was identified to be an independent and significant prognostic factor for overall survival (P=0.040), but not for disease-free survival (P=0.051). Collectively, the present data suggest that TRPM8 may play a crucial role in the development and progression of OS, and thus may be considered as a novel molecular target for therapy in patients with OS.

Involvement of ion channels and transporters in carcinoma angiogenesis and metastasis

Angiogenesis is a finely tuned process, which is the result of the equilibrium between pro- and antiangiogenic factors. In solid tumor angiogenesis, the balance is highly in favor of the production of new, but poorly functional blood vessels, initially intended to provide growing tumors with nutrients and oxygen. Among the numerous proteins involved in tumor development, several types of ion channels are overexpressed in tumor cells, as well as in stromal and endothelial cells. Ion channels thus actively participate in the different hallmarks of cancer, especially in tumor angiogenesis and metastasis. Indeed, from their strategic localization in the plasma membrane, ion channels are key operators of cell signaling, as they sense and respond to environmental changes. This review aims to decipher how ion channels of different families are intricately involved in the fundamental angiogenesis and metastasis hallmarks, which lead from a nascent tumor to systemic dissemination. An overview of the possible use of ion channels as therapeutic targets will also be given, showing that ion channel inhibitors or specific antibodies may provide effective tools, in the near future, in the treatment of carcinomas.

Roles of TRPM8 Ion Channels in Cancer: Proliferation, Survival, and Invasion

The goal of this article is to provide a critical review of the transient receptor potential melastatin-subfamily member 8 (TRPM8) in cancers, with an emphasis on its roles in cellular proliferation, survival, and invasion. The TRPM8 ion channels regulate Ca²⁺ homeostasis and function as a cellular sensor and transducer of cold temperature. Accumulating evidence has demonstrated that TRPM8 is aberrantly expressed in a variety of malignant solid tumors. Clinicopathological analysis has shown that over-expression of TRPM8 correlates with tumor progression. Experimental data have revealed important roles of TRPM8 channels in cancer cells proliferation, survival, and invasion, which appear to be dependent on the cancer type. Recent reports have begun to reveal the signaling mechanisms that mediate the biological roles of TRPM8 in tumor growth and metastasis. Determining the mechanistic roles of TRPM8 in cancer is expected to elucidate the impact of thermal and chemical stimuli on the formation and progression of neoplasms. Translational research and clinical investigation of TRPM8 in malignant diseases will help exploit these ion channels as molecular biomarkers and therapeutic targets for developing precision cancer medicine.