Significance and expression of aquaporin 1, 3, 8 in cervical carcinoma in Xinjiang Uygur women of China

Aquaporins in colorectal cancer: exploring their role in tumorigenesis, metastasis, and drug response

Aquaporins (AQPs) are small, integral proteins facilitating water transport across plasma cell membranes in response to osmotic gradients. This family has 13 unique members (AQP0-12), which can also transport glycerol, urea, gases, and other salute small molecules. AQPs play a crucial role in the regulation of different cellular processes, including metabolism, migration, immunity, barrier function, and angiogenesis. These proteins are found to aberrantly overexpress in various cancers, including colorectal cancer (CRC). Growing evidence has explored AQPs as a potential diagnostic biomarker and therapeutic target in different cancers. However, there is no comprehensive review compiling the available information on the crucial role of AQPs in the context of colorectal cancer. This review highlights the significance of AQPs as the biomarker and regulator of tumor cells metabolism. In addition, the proliferation, angiogenesis, and metastasis of tumor cells related to AQPs expression as well as function are discussed. Understanding the AQPs prominent role in chemotherapy resistance is of great importance clinically.

Importance of Water Transport in Mammalian Female Reproductive Tract

Aquaporins (AQPs) are involved in water homeostasis in tissues and are ubiquitous in the reproductive tract. AQPs are classified into classical aquaporins (AQP0, 1, 2, 4, 5, 6 and 8), aquaglycerolporins (AQP3, 7, 9, and 10) and superaquaporins (AQP11 and 12). Nine AQPs were described in the mammalian female reproductive tract. Some of their functions are influenced by sexual steroid hormones. The continuous physiological changes that occur throughout the sexual cycle, pregnancy and parturition, modify the expression of AQPs, thus creating at every moment the required water homeostasis. AQPs in the ovary regulate follicular development and ovulation. In the vagina and the cervix, AQPs are involved mainly in lubrication. In the uterus, AQPs are mostly mediated by estradiol and progesterone to prepare the endometrium for possible embryo implantation and fetal development. In the placenta, AQPs are responsible for the fluid support to the fetus to maintain fetal homeostasis that ensures correct fetal development as pregnancy goes on. This review is focused on understanding the role of AQPs in the mammalian female reproductive tract during the sexual cycle of pregnancy and parturition.

Aquaporins in Reproductive System

AQP0-12, a total of 13 aquaporins are expressed in the mammalian reproductive system. These aquaporins mediate the transport of water and small solutes across biofilms for maintaining reproductive tract water balance and germ cell water homeostasis. These aquaporins play important roles in the regulation of sperm and egg cell production, maturation, and fertilization processes. Impaired AQP function may lead to diminished male and female fertility. This review focuses on the distribution, function, and regulation of AQPs throughout the male and female reproductive organs and tracts. Their correlation with reproductive success, revealing recent advances in the physiological and pathophysiological roles of aquaporins in the reproductive system.

KLF5-mediated aquaporin 3 activated autophagy to facilitate cisplatin resistance of gastric cancer

BACKGROUND

Resistance to chemotherapeutic drugs limits the control of gastric cancer (GC) development. The study intended to probe into the mechanism of aquaporin 3 (AQP3) on the chemoresistance of GC.

METHODS

Cisplatin (CDDP)-resistant cells were constructed. Parental AGS and HGC-27 cells and their respective CDDP-resistant cells were transfected with AQP3 overexpression plasmid, AQP3 short hairpin RNA (sh-AQP3) and sh-Kruppel-like factor 5 (shKLF5). The expressions of AQP3 and factors related to autophagy (LC3 I, LC3 II, Atg5, Beclin-1, p62)/epithelial-mesenchymal transition (EMT; E-cadherin and snail) were assessed by Western blot and qRT-PCR. Cell counting kit-8 assay was adopted to test cell viability and half maximal inhibitory concentration (IC 50) was determined. Transwell assay was used for the examination of cell migration and invasion. The regulatory relationship of AQP3 and KLF5 was tested by chromatin immunoprecipitation (ChIP) and dual luciferase reporter assays.

RESULTS

AQP3 was highly-expressed in GC cells and its level was even higher in CDDP-resistant GC cells. AQP3 silencing inhibited viability, autophagy and EMT in CDDP-resistant GC cells, while AQP3 overexpression had the opposite effect. KLF5 positively modulated AQP3 in GC cells resistant to CDDP. KLF5 knockdown reversed AQP3-induced autophagy, viability, migration, invasion and EMT in CDDP-resistant GC cells.

CONCLUSION

KLF5-modulated AQP3 activated autophagy to facilitate the resistance of GC to CDDP.

The Expression of Aquaporin-1 and Aquaporin-3 in Extrahepatic Cholangiocarcinoma and their Clinicopathological Significance

BACKGROUND

The aim of the study was to evaluate the expression and clinicopathological significance of aquaporin-1 (AQP1) and aquaporin-3 (AQP3) in extrahepatic cholangiocarcinoma (EHCC).

METHODS

Immunostaining of AQP1 and AQP3 was performed by EnVision immunohistochemistry in benign and malignant biliary tract tissues.

RESULTS

The expression of AQP1 and AQP3 protein were significantly higher in EHCC tumor tissues (P < 0.05 or P < 0.01). Adenoma and paracancerous tissues with positive AQP1 and/or AQP3 protein expression exhibited atypical hyperplasia. AQP1 expression was positive correlated with AQP3 expression in EHCC (P < 0.01). TNM I + II stage and radical surgery, the positive expression of AQP1 and AQP3 In patients with well-differentiation, no invasion, no lymph metastasis, is lower (P < 0.05 or P < 0.01). Average overall survival time of those with positive expression of AQP1 and AQP3 was significant shorter (P < 0.01). Both AQP1 and AQP3 positive expressions were proved to be an independent prognostic factors in EHCC by cox multivariate analysis. The AUC calculated for AQP1 was 0.769 (95% confidence interval [CI]: 0.618-0.920), and that for AQP3 was 0.758 (95%CI: 0.605-0.911, while that for AQP1 and AQP3 was 0.825 (95%CI: 0.658-0.991).

CONCLUSIONS

Positive expression of AQP1 and AQP3 is closely related to the pathogenesis, severe clinicopathological characteristics, aggressive biological behaviors, and dismal prognoses in EHCC.

Targeting Aquaporins in Novel Therapies for Male and Female Breast and Reproductive Cancers

Aquaporins are membrane channels in the broad family of major intrinsic proteins (MIPs), with 13 classes showing tissue-specific distributions in humans. As key physiological modulators of water and solute homeostasis, mutations, and dysfunctions involving aquaporins have been associated with pathologies in all major organs. Increases in aquaporin expression are associated with greater severity of many cancers, particularly in augmenting motility and invasiveness for example in colon cancers and glioblastoma. However, potential roles of altered aquaporin (AQP) function in reproductive cancers have been understudied to date. Published work reviewed here shows distinct classes aquaporin have differential roles in mediating cancer metastasis, angiogenesis, and resistance to apoptosis. Known mechanisms of action of AQPs in other tissues are proving relevant to understanding reproductive cancers. Emerging patterns show AQPs 1, 3, and 5 in particular are highly expressed in breast, endometrial, and ovarian cancers, consistent with their gene regulation by estrogen response elements, and AQPs 3 and 9 in particular are linked with prostate cancer. Continuing work is defining avenues for pharmacological targeting of aquaporins as potential therapies to reduce female and male reproductive cancer cell growth and invasiveness.

Aquaporins and (in)fertility: More than just water transport

Aquaporins (AQPs) are a family of channel proteins that facilitate the transport of water and small solutes across biological membranes. They are widely distributed throughout the organism, having a number of key functions, some of them unexpected, both in health and disease. Among the various diseases in which AQPs are involved, infertility has been overlooked. According to the World Health Organization (WHO) infertility is a global public health problem with one third of the couples suffering from subfertility or even infertility due to male or female factors alone or combined. Thus, there is an urgent need to unveil the molecular mechanisms that control gametes production, maturation and fertilization-related events, to more specifically determine infertility causes. In addition, as more couples seek for fertility treatment through assisted reproductive technologies (ART), it is pivotal to understand how these techniques can be improved. AQPs are heterogeneously expressed throughout the male and female reproductive tracts, highlighting a possible regulatory role for these proteins in conception. In fact, their function, far beyond water transport, highlights potential intervention points to enhance ART. In this review we discuss AQPs distribution and structural organization, functions, and modulation throughout the male and female reproductive tracts and their relevance to the reproductive success. We also highlight the most recent advances and research trends regarding how the different AQPs are involved and regulated in specific mechanisms underlying (in)fertility. Finally, we discuss the involvement of AQPs in ART-related processes and how their handling can lead to improvement of infertility treatment.

The Relevance of Aquaporins for the Physiology, Pathology, and Aging of the Female Reproductive System in Mammals

Aquaporins constitute a group of water channel proteins located in numerous cell types. These are pore-forming transmembrane proteins, which mediate the specific passage of water molecules through membranes. It is well-known that water homeostasis plays a crucial role in different reproductive processes, e.g., oocyte transport, hormonal secretion, completion of successful fertilization, blastocyst formation, pregnancy, and birth. Further, aquaporins are involved in the process of spermatogenesis, and they have been reported to be involved during the storage of spermatozoa. It is noteworthy that aquaporins are relevant for the physiological function of specific parts in the female reproductive system, which will be presented in detail in the first section of this review. Moreover, they are relevant in different pathologies in the female reproductive system. The contribution of aquaporins in selected reproductive disorders and aging will be summarized in the second section of this review, followed by a section dedicated to aquaporin-related proteins. Since the relevance of aquaporins for the male reproductive system has been reviewed several times in the recent past, this review aims to provide an update on the distribution and impact of aquaporins only in the female reproductive system. Therefore, this paper seeks to determine the physiological and patho-physiological relevance of aquaporins on female reproduction, and female reproductive aging.

Assessing the Expression of Aquaporin 3 Antigen-Recognition Sites in Oral Squamous Cell Carcinoma

Aquaporin 3 (AQP3) serves as a water and glycerol transporter facilitating epithelial cell hydration. Recently, the involvement of AQP3 in cancers has been reported. However, the immunohistochemical expression of AQP3 in carcinomas remains controversial. We hypothesized that differences in aquaporin 3 antigen recognition (AQP3 AR) may influence their expressions. Thus, our study aimed to assess the immunostaining patterns of 3 AQP3 AR sites in oral squamous cell carcinoma (OSCC) and to compare the adjacent areas of high-grade epithelial dysplasia (HG-ED) and normal oral mucosa (NOM). The study group included formalin-fixed OSCC samples (n=51) with adjacent regions of HG-ED (n=12) and NOM (n=51). The tissues were stained with anti-AQP3 antibodies (AR sites at amino acid (AA) 250-C terminus, AA180-228, and N terminus AA1-80) by immunohistochemistry. Our results showed that strong membranous immunostaining was observed for AQP3 AR sites at the AA250-C terminus and AA180-228 in all the samples for NOM and weak AQP3 immunostaining for both the AR sites in all the 12 samples for HG-ED. The invasive front of OSCC samples showed that AQP3 AR at the AA250-C terminus decreased in 42/51 samples (82.4%) and AA180-228 in 47/51 samples (92.2%). Conversely, in the AQP3 AR site at N terminus AA1-80, all samples of the NOM showed negative or slightly positive staining in the cytoplasm of the lower layers. AQP3 expression was increased in 12/12 cases (100%) and 46/51 cases (90.2%) in the HG-ED and invasive front of OSCC, respectively. AQP3 may be used as a biomarker for detecting malignant transformations. AQP3 AR site differences influence their immunohistochemical expression in OSCC.

Combined Systematic Review and Transcriptomic Analyses of Mammalian Aquaporin Classes 1 to 10 as Biomarkers and Prognostic Indicators in Diverse Cancers

Aquaporin (AQP) channels enable regulated transport of water and solutes essential for fluid homeostasis, but they are gaining attention as targets for anticancer therapies. Patterns of AQP expression and survival rates for patients were evaluated by systematic review (PubMed and Embase) and transcriptomic analyses of RNAseq data (Human Protein Atlas database). Meta-analyses confirmed predominantly negative associations between AQP protein and RNA expression levels and patient survival times, most notably for AQP1 in lung, breast and prostate cancers; AQP3 in esophageal, liver and breast cancers; and AQP9 in liver cancer. Patterns of AQP expression were clustered for groups of cancers and associated with risk of death. A quantitative transcriptomic analysis of AQP1-10 in human cancer biopsies similarly showed that increased transcript levels of AQPs 1, 3, 5 and 9 were most frequently associated with poor survival. Unexpectedly, increased AQP7 and AQP8 levels were associated with better survival times in glioma, ovarian and endometrial cancers, and increased AQP11 with better survival in colorectal and breast cancers. Although molecular mechanisms of aquaporins in pathology or protection remain to be fully defined, results here support the hypothesis that overexpression of selected classes of AQPs differentially augments cancer progression. Beyond fluid homeostasis, potential roles for AQPs in cancers (suggested from an expanding appreciation of their functions in normal tissues) include cell motility, membrane process extension, transport of signaling molecules, control of proliferation and apoptosis, increased mechanical compliance, and gas exchange. AQP expression also has been linked to differences in sensitivity to chemotherapy treatments, suggesting possible roles as biomarkers for personalized treatments. Development of AQP pharmacological modulators, administered in cancer-specific combinations, might inspire new interventions for controlling malignant carcinomas.

AQP1 and AQP3 Expression are Associated With Severe Symptoms and Poor-prognosis of the Pancreatic Ductal Adenocarcinoma

BACKGROUND

Approximately 80% of patients with pancreatic ductal adenocarcinoma (PDAC) have metastatic disease with poor prognosis, but clinically available biomarkers for the diagnosis, prediction of prognosis, and target therapy have not yet been identified.

OBJECTIVE

To investigate the expression of aquaporin-1 (AQP1) and AQP3 protein and their clinicopathological significances in PDACs.

MATERIALS AND METHOD

AQP1 and AQP3 protein expression in 106 PDAC, 35 peritumoral tissues, 55 benign pancreatic lesions, and 13 normal pancreatic tissues was measured by immunohistochemistry.

RESULTS

Western blot showed that AQP1 and AQP3 protein expression was significantly higher in PDAC tissues than that in benign pancreatic tissues (P<0.01). Immunohistochemistry showed that the percentages of positive AQP1 and AQP3 expressions were significantly higher in PDAC tumors than that in peritumoral tissues, benign, and normal pancreatic tissues (P<0.01). Benign pancreatic lesions with positive AQP1 and AQP3 expression exhibited a dysplasia or intraepithelial neoplasia. The percentage of cases with positive AQP1 and AQP3 expression was significantly lower in PDAC patients without lymph node metastasis and invasion, and having low Tumor, Node and Metastasis (TNM) stage disease than in patients with lymph node metastasis, invasion, and high TNM stage disease (P<0.05 or <0.01). Kaplan-Meier survival analysis showed that positive AQP1 and AQP3 expression were significantly associated with survival in PDAC patients (P<0.001). Cox multivariate analysis revealed that positive AQP1 and AQP3 expression was independent poor prognosis factors in PDAC patients. The area under the curve of receiver operating characteristic curve was 0.669 for AQP1 and 0.707 for AQP3, respectively.

CONCLUSIONS

Positive AQP1 and AQP3 expressions are associated with the tumorigenesis and progression of PDAC. Both AQP1 and AQP3 are a diagnostic marker of PDAC and a predictive marker of poor prognosis in PDAC patients.

Prognostic implications of Aquaporin 9 expression in clear cell renal cell carcinoma

Background

Growing evidence has demonstrated immune reactivity as a confirmed important carcinogenesis and therapy efficacy for clear cell renal cell carcinoma (ccRCC). Aquaporin 9 (AQP9) is involved in many immune-related signals; however, its role in ccRCC remains to be elucidated. This study investigated AQP9 expression in tumor tissues and defined the prognostic value in ccRCC patients.

Methods

A total of 913 ccRCC patients with available RNA-sequence data from the Cancer Genome Atlas (TCGA) database and Fudan University Shanghai Cancer Center (FUSCC) were consecutively recruited in analyses. Differential transcriptional and proteome expression profiles were obtained and validated using multiple datasets. A partial likelihood test from Cox regression analysis was developed to address the influence of independent factors on progression-free survival (PFS) and overall survival (OS). The Kaplan–Meier method and log-rank test were performed to assess survival. Receiver operating characteristic (ROC) curves were used to describe binary classifier value of AQP9 using area under the curve (AUC) score. Functional enrichment analyses and immune infiltration analysis were used to describe significantly involved hallmark pathways of hub genes.

Results

Significantly elevated transcriptional and proteomic AQP9 expressions were found in ccRCC samples. Increased AQP9 mRNA expression was significantly associated with advanced clinicopathological parameters and correlated with shorter PFS and OS in TCGA and FUSCC cohorts (p < 0.001). ROC curves suggested the significant diagnostic and prognostic ability of AQP9 (PFS, AUC = 0.823; OS, AUC = 0.828). Functional annotations indicated that AQP9 is involved in the most significant hallmarks including complement, coagulation, IL6/JAK–STAT3, inflammatory response and TNF-alpha signaling pathways.

Conclusion

Our study revealed that elevated AQP9 expression was significantly correlated with aggressive progression, poor survival and immune infiltrations in ccRCC patients, and we validated its prognostic value in a real-world cohort. These data suggest that AQP9 may act as an oncogene and a promising prognostic marker in ccRCC.

Decreased expression of aquaporin 1 correlates with clinicopathological features of patients with cervical cancer

Purpose: We aimed to investigate the expression dynamics of Aquaporin 1 (AQP1) in cervical cancer and evaluate correlations among AQP1 levels and the clinicopathological features of patients with cervical cancer.

Patients and methods:AQP1 mRNA and protein levels in cervical cancer and adjacent normal tissues were evaluated by quantitative reverse-transcription PCR (qRT-PCR) and western blot. Immunohistochemistry (IHC) for AQP1 was performed with a tissue microarray of cervical cancer (containing 63 cases of squamous cell cervical cancers and 10 normal cervical tissues) to investigate clinicopathological outcomes. Cut-off scores for positive expression of AQP1 were determined by receiver operating characteristic analysis. The χ² test was used to analyze correlations among AQP1 expression and clinicopathological features of cervical cancer.

Results: The expression of AQP1 was decreased in the majority of cervical cancer tissues by qRT-PCR and western blot analysis. Positive expression of AQP1 was observed in 100% (10/10) of normal cervical tissues and in 42.86% (27/63) of cervical cancer tissues by IHC analysis. The cut-off score for positive expression of AQP1 was determined to be 45% of cancer cells. Decreased expression of AQP1 was correlated with clinicopathological features including; poor pathological grade (P=0.000), late International Federation of Gynecology and Obstetrics stage (P=0.008), and positive lymph nodes (P=0.002).

Conclusion: These data suggest that decreased expression of AQP1 correlated with progressive features in patients with cervical cancer. AQP1 levels may serve as a potential biomarker for the diagnosis of cervical cancer.

Aquaporins 1, 3 and 5 in Different Tumors, their Expression, Prognosis Value and Role as New Therapeutic Targets

All different types of metabolism of tumors are dependent on the flow of water molecules through the biological membrane, where fluid transfer interceded by aquaporins (AQPs) are the basis means for water entrance into the cells or outside them. Aquaporins play other roles including cellular migration, cellular expansion and cellular adhesion facilitation. Therefore, regulators of AQPs may be useful anticancer agents. Medline, Scopus, Embase, and Web of Sciences were searched. From among the papers found, 106 were related to the subject. All of the examined cancers in relation to AQP1 included adenoid cystic carcinoma, bladder, breast, cervical, colon, colorectal, hepatocellular, lung, ovarian, plural mesothelioma, prostate, renal cell carcinoma and squamous cell carcinoma. All of the studied cancers in relation with AQP3 included gastric, breast, prostate, lung, pancreas, skin, bladder, squamous cell carcinoma, cervical, adenoid cystic carcinoma, colon, colorectal, ovarian, and hepatocellular cancers and with regard to AQP5 were lung, squamous cell carcinoma, ovarian, adenoid cystic carcinoma, breast, colon, colorectal, hepatic, pancreas, gallbladder, prostate, and gastric cancers. Over or under-expression of AQP1, 3 and is exist in the mentioned cancers across different studies. Over-expression of AQP1, AQP3 and AQP5 is clearly associated with carcinogenesis, metastasis, reduced survival rate, lymph node metastasis, poorer prognosis, and cellular migration. Also, cancer treatments in relation to these markers suggest AQP reduction during the treatment.

Aquaporins in cancer development: opportunities for bioinorganic chemistry to contribute novel chemical probes and therapeutic agents

Aquaporins (AQPs) are membrane proteins allowing permeation of water, glycerol & hydrogen peroxide across biomembranes, and playing an important role in water homeostasis in different organs, exocrine gland secretion, urine concentration, skin moisturization, fat metabolism and neural signal transduction. Notably, a large number of studies showed that AQPs are closely associated with cancer biological functions and expressed in more than 20 human cancer cell types. Furthermore, AQP expression is positively correlated with tumour types, grades, proliferation, migration, angiogenesis, as well as tumour-associated oedema, rendering these membrane channels attractive as both diagnostic and therapeutic targets in cancer. Recent developments in the field of AQPs modulation have identified coordination metal-based complexes as potent and selective inhibitors of aquaglyceroporins, opening new avenues in the application of inorganic compounds in medicine and chemical biology. The present review is aimed at providing an overview on AQP structure and function, mainly in relation to cancer. In this context, the exploration of coordination metal compounds as possible inhibitors of aquaporins may open the way to novel chemical approaches to study AQP roles in tumour growth and potentially to new drug families. Thus, we describe recent results in the field and reflect upon the potential of inorganic chemistry in providing compounds to modulate the activity of "elusive" membrane targets as the aquaporins.

AQP9 promotes astrocytoma cell invasion and motility via the AKT pathway

The aquaporin (AQP) family, which includes 13 members identified in mammalian cells, is involved in cancer development and progression. AQP9 expression is upregulated in several tumor tissue types. However, the functions of AQP9 in astrocytoma remain elusive. The present study identified that AQP9 was expressed in astrocytoma cells. AQP9 expression was silenced by transfection with small interfering RNAs and increased by transfection with a plasmid containing the AQP9 gene. Using invasion and wound-healing assays, it was revealed that the knockdown of AQP9 suppressed astrocytoma cell invasion and motility, whereas overexpression of AQP9 promoted the invasion and motility of astrocytoma cells. It was further revealed that AQP9 could induce RAC serine/threonine-protein kinase (AKT) activation and decrease E-cadherin expression in astrocytoma cells. Inhibition of the AKT pathway attenuated AQP9-mediated invasion, motility and E-cadherin expression. Taken together, the results of the present study indicated that AQP9 promoted the invasion and motility of cells via the AKT pathway. Therefore, AQP9 may represent a potential target for therapeutic use of astrocytoma.

Prognostic values of aquaporins mRNA expression in human ovarian cancer

Aquaporins (AQPs), a family of transmembrane channel, are composed of 13 identified members (AQP0–12). Accumulating evidences reported that AQPs were correlated with various biological roles and represented a prognostic predictor in various cancer types. However, the prognostic value of AQPs expression in ovarian cancer remains unclear. Using ‘Kaplan–Meier plotter’ (KM plotter) online database, we explored the predictive prognostic value of individual AQPs members’ mRNA expression to overall survival (OS) in different clinical data, such as histology, pathological grades, clinical stages, TP53 status, and applied chemotherapy in ovarian cancer patients. Our results revealed that higher AQP0, AQP1, and AQP4 mRNA expression were correlated with poor OS, whereas higher AQP3, AQP5, AQP6, AQP8, AQP10, and AQP11 showed better OS in ovarian cancer patients. Moreover, AQP4 and AQP8 showed poor OS in TP53-mutated ovarian cancer patients and AQP1 presented unfavorable OS in both TP53 mutated and wild ovarian cancer patients. Additionally, AQP3, AQP6, and AQP11 mRNA expression were correlated with better OS, whereas AQP0 and AQP1 showed poor OS in all ovarian cancer patients treated with Platin, Taxol, and Taxol + Platin chemotherapy. AQP5, AQP8, and AQP10 were associated with improved OS, however, AQP4 predicted unfavorable OS in all patients treated with Platin chemotherapy. Our results suggest that individual AQPs, except AQP2 and AQP9, are associated with unique prognostic significance and may thus act as new predictive prognostic indicators and potential drug therapeutic target in ovarian cancer.

Mechanisms of Aquaporin-Facilitated Cancer Invasion and Metastasis

Cancer is a leading cause of death worldwide, and its incidence is rising with numbers expected to increase 70% in the next two decades. The fact that current mainline treatments for cancer patients are accompanied by debilitating side effects prompts a growing demand for new therapies that not only inhibit growth and proliferation of cancer cells, but also control invasion and metastasis. One class of targets gaining international attention is the aquaporins, a family of membrane-spanning water channels with diverse physiological functions and extensive tissue-specific distributions in humans. Aquaporins−1,−2,−3,−4,−5,−8, and−9 have been linked to roles in cancer invasion, and metastasis, but their mechanisms of action remain to be fully defined. Aquaporins are implicated in the metastatic cascade in processes of angiogenesis, cellular dissociation, migration, and invasion. Cancer invasion and metastasis are proposed to be potentiated by aquaporins in boosting tumor angiogenesis, enhancing cell volume regulation, regulating cell-cell and cell-matrix adhesions, interacting with actin cytoskeleton, regulating proteases and extracellular-matrix degrading molecules, contributing to the regulation of epithelial-mesenchymal transitions, and interacting with signaling pathways enabling motility and invasion. Pharmacological modulators of aquaporin channels are being identified and tested for therapeutic potential, including compounds derived from loop diuretics, metal-containing organic compounds, plant natural products, and other small molecules. Further studies on aquaporin-dependent functions in cancer metastasis are needed to define the differential contributions of different classes of aquaporin channels to regulation of fluid balance, cell volume, small solute transport, signal transduction, their possible relevance as rate limiting steps, and potential values as therapeutic targets for invasion and metastasis.

Effect of selective inhibition of aquaporin 1 on chemotherapy sensitivity of J82 human bladder cancer cells

The occurrence of resistance to mitomycin C (MMC) often limits its clinical effectiveness. Combination therapy thus is employed to overcome this treatment resistance. The present study aimed to establish a novel J82 bladder cancer cell line so as to study the effect of inhibition of aquaporin 1 (AQP-1) on chemotherapy sensitivity of J82 bladder cancer cells. A novel J82 bladder cancer cell line whose expression of AQP-1 is inhibited was established through transfection of J82 cells with newly constructed recombinant plasmid. The resulting cell line was designated J82-short hairpin (sh)AQP1 and was subjected to further analyses together with J82 cell line. Reverse transcription-polymerase chain reaction was used to quantify the expression of AQP-1mRNA in the cells; cell viability was analyzed with MTT assay and apoptosis was measured by flow cytometry. The expression of cell proliferation and cell apoptosis-associated proteins, proliferating cell nuclear antigen (PCNA), B cell lymphoma 2 (Bcl-2), Bcl-2 associated X protein (Bax) and caspase-3, were detected by Western blot. A statistically significant decrease in the transcription and expression of AQP1 was observed in the J82-shAQP1 cells as compared with J82 cells. J82-shAQP1 cells treated by MMC, also had a lower cell viability than J82 cells treated by MMC and showed enhanced apoptosis. Western blot analysis revealed J82-shAQP1 cells treated by MMC had less expression of PCNA, lower bcl-2/Bax ratio and more expression of caspase-3 as compared with the J82 cells treated by MMC. Selective inhibition of AQP-1 enhanced MMC chemotherapy sensitivity of J82 bladder cancer cells, suggesting combination of AQP-1 inhibition with MMC treatment as a promising treatment strategy to overcome bladder cancer treatment resistance.

Aquaporin-1 expression as an indicator in evaluating the efficacy of meloxicam in the treatment of ankylosing spondylitis: A comparative study

OBJECTIVE

The key objective of the study was to investigate the correlation between the expression of aquaporin-1 (AQP1) and the efficacy of meloxicam and expressions of pro-inflammatory cytokines in ankylosing spondylitis (AS).

METHODS

40 AS patients whom had received meloxicam were recruited and subsequently placed into the experiment, while 40 healthy individuals were recruited as control group. Clinical indicators were detected before treatment (0 week), and at 2, 4, 6, 8, 10 and 12 week intervals after treatment, which included various assessments including Ankylosing Spondylitis 20% (ASAS20) response, Bath ankylosing spondylitis disease activity index (BASDAI), visual analog scale (VAS) for back pain, duration of morning stiffness, Bath ankylosing spondylitis functional index (BASFI), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) levels. Healthy volunteers were examined for ESR and CRP levels. The mRNA and protein expressions of AQP1 and pro-inflammatory cytokines, tumor necrosis factor-α (TNF-α) and interleukin-2 (IL-2), in peripheral blood mononuclear cells (PBMCs) were detected 6 and 12 weeks after treatment using reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blotting. Correlation of expressions of AQP1, efficacy of meloxicam and expression of pro-inflammatory cytokines were determined via Pearson correlation analysis.

RESULTS

Following 12 weeks of meloxicam treatment, the ASAS20 response reached 93.7±3.61%. 6 weeks after treatment, BASDAI, VAS for back pain, duration of morning stiffness, BASFI, ESR, and CRP levels all exhibited considerably reduced levels compared to the initial levels observed prior to the commencement of treatment. Compared with before treatment, the expressions of TNF-α, IL-2 and AQP1 mRNA and protein all displayed decreases in the experiment group after both 6 and 12-week periods of treatment. Pre and post treatment levels of TNF-α, IL-2 and AQP1 mRNA and protein expressions were higher than those in the control group. The expressions of AQP1 mRNA and protein in the experiment group were positively correlated with clinical indicators and expressions of pro-inflammatory cytokines.

CONCLUSION

Our findings indicated that AQP1 was both highly expressed and positively correlated with the efficacy of meloxicam and expressions of pro-inflammatory cytokines in AS patients, thereby highlighting the promise of meloxicam as a potential indicator in predicting the efficacy in the treatment of AS.

Expression of aquaporin1, a water channel protein, in cytoplasm is negatively correlated with prognosis of breast cancer patients

Aquaporin1 (AQP1) belongs to a highly conserved family of aquaporin proteins which facilitate water flux across cell membranes. Although emerging evidences indicated the cytoplasm was important for AQP1 localization, the function of AQP1 corresponding to its cytoplasmic distribution has rarely been explored until present. In our clinical study, we reported for the first time that AQP1 was localized dominantly in the cytoplasm of cancer cells of invasive breast cancer patients and cytoplasmic AQP1 was an independent prognostic factor. High expression of AQP1 indicated a shorter survival, especially in luminal subtype. Moreover, in line with our findings in clinic, cytoplasmic expression of AQP1 was further validated in both primary cultured breast cancer cells and AQP1 over-expressing cell lines, in which the functional importance of cytoplasmic AQP1 was confirmed in vitro. In conclusion, our study provided the first evidence that cytoplasmic expression of AQP1 promoted breast cancer progression and it could be a potential prognostic biomarker for breast cancer.

Aquaporin 1 protein expression is associated with BRAF V600 mutation and adverse prognosis in cutaneous melanoma

Despite experimental findings suggesting the prognostic significance of Aquaporin 1 (AQP1) in human melanoma, no published clinical data are available. We studied the expression of AQP1 protein in cutaneous melanoma, correlated our findings with standard histological and genetic markers, and long-term clinical follow-up. Our study evaluated the AQP1 protein expression in 78 melanoma patients, representing two predefined risk cohorts using the immune labeling technique with commercially available anti-AQP1 antibodies on routinely formalin-fixed and paraffin-embedded tumor tissue samples. BRAF V600E mutation analyses were carried out successfully in 70 patients using PCR and restriction fragment length polymorphism analyses, followed by confirmatory analysis with the Sanger sequencing technique. AQP1-expressing melanoma cells were found in 52 cases (66.7%, median H-score=124.24). Significantly higher AQP1 H-scores (P=0.047) were found in the 'high-risk' patients. No correlations were found with the established histological markers, such as mitotic index (P=0.42), Clark level (P=0.95), and Breslow thickness (P=0.51). BRAF V600 mutation analyses were successful in 89%, and showed a two times higher mutation frequency in the 'high-risk' group. The BRAF V600 mutations were significantly associated with AQP1 expression (P=0.014). Long-term follow-up indicated a reduced progression-free survival (P=0.036) and overall survival (P=0.017) for the AQP1-positive cutaneous melanoma patients. AQP1 expression is likely to be associated with an adverse prognosis in cutaneous melanoma.

Differential Expression of Aquaporins in Cervical Precursor Lesions and Invasive Cervical Cancer

OBJECTIVE

Aquaporins (AQPs) are highly expressed in tumor cells of different origins, particularly the aggressive tumors. The aim of this study was to investigate the expression of AQP isoforms during progression of squamous cervical cancer (SCC) and explore their associations with clinicopathologic variables of SCC.

METHODS

Expression of AQP isoforms (1, 3, 4, 5, and 8) was detected by immunohistochemistry in 47 SCCs, 37 cervical intraepithelial neoplasia (CIN), and 16 normal cervical tissues. Specific expression of AQP protein in SCC was detected by Western blot. Double immunohistochemistry was used to examine whether AQPs and vascular endothelial growth factor (VEGF) are coexpressed in SCC.

RESULTS

Aquaporin 1 showed higher positivity rate in CIN than in SCC and normal cervical tissues (P < .05). The expression intensity of AQP3, 4, 5, and 8 was higher in SCC than that in normal cervical tissues, respectively (P < .05). The expression of AQP3 and 8 was higher in SCC than that in CIN, respectively (P < .05). The AQP4 expression was higher in CIN than in normal cervical tissues (P < .05). The expression of AQP3 in CIN III was higher than that in CIN I and II (P < .05). There was a significant increase in the expression of AQP1 in stage I than that in stage II (P < .05). Aquaporin 3 showed lower positivity in moderately and well-differentiated tumors compared to that in poorly differentiated tumors (P < .05). Finally, double immunohistochemistry illustrated that AQP1/AQP3/AQP8 and VEGF were coexpressed in SCC.

CONCLUSIONS

Different AQP isoforms display specific expression patterns in normal cervical, CIN, and SCC tissues. This and the significant association with the clinicopathologic variables of SCC suggest that AQP isoforms might play different roles in the development of cervical cancer.

Expression of aquaporin 1 in bladder uroepithelial cell carcinoma and its relevance to recurrence

OBJECTIVES

To explore the expression of aquaporin 1 (AQP1) in bladder uroepithelium cell carcinoma (BUCC) and its relevance to recurrence.

MATERIALS AND METHODS

Tissue samples from 45 BUCC patients who underwent total cystectomy or transurethral resection of bladder tumor (TURBT) and from 40 patients with non-bladder cancers who underwent special detection or treatments were collected. The level of expression of AQP1 in BUCC tissues and normal bladder tissues was assessed by immunohistochemistry so as to analyze the relevance to pathological patterns and time of recurrence in BUCC patients.

RESULTS

The expression levels of AQP1 normal bladder tissues and BUCC tissues were 2.175±0.693 and 3.689±0.701, respectively, and the difference was significant (t=9.99, P<0.0001). Marked increase was noted with BUCC histological grade and pathological stage (P<0.01). Moreover, the expression of AQP1 was evidently higher in cancerous tissues with lymph node metastasis than in those without (P<0.01). With short-term recurrence, the positive cell expression rate of AQP1 was higher in primary tissues, which increased obviously after recurrence. Additionally, the recurrent time of BUCC was negatively associated with the positive cell expression rate of AQP1 and the difference between the expression of AQP1 before and after recurrence (r=-0.843, F=39.302, P=0.000; r=-0.829, F=35.191, P=0.000).

CONCLUSIONS

AQP1, which reflects the grade, stage, lymph node metastasis and recurrence of BUCC, has potential guiding significance in the diagnosis and treatment of bladder cancarcinoma.

Identification of Estrogen Response Element in Aquaporin-3 Gene that Mediates Estrogen-induced Cell Migration and Invasion in Estrogen Receptor-positive Breast Cancer

Accumulating evidence suggests that aquaporins (AQPs) may facilitate tumor development. The molecular pathways connecting the pathological functions of AQPs are unclear and need to be better defined. This study aimed to investigate whether AQP3, one of the AQPs expressed highly in breast cancer, had any clinical implication in estrogen-receptor (ER) positive breast cancer, and explore the regulatory mechanisms of AQP3 in estrogen-related breast cancer progression. Here we show that AQP3 is an important enforcer of migration and invasion in breast cancer. We, for the first time, reported that ER-positive breast cancer tissues obtained from premenopausal patients had higher AQP3 expression when compared to those obtained from postmenopausal patients. Estrogen directly upregulates AQP3 by activating ERE in the promoter of the AQP3 gene. The upregulation of AQP3 can influence the expression of molecules related to epithelial-mesenchymal transition and the reorganization of actin-cytoskeleton, resulting in enhancement of cell migration and invasion in ER-positive breast cancer cells.

Simultaneous changes of magnetic resonance diffusion-weighted imaging and pathological microstructure in locally advanced cervical cancer caused by neoadjuvant chemotherapy

PURPOSE

To investigate the changes to diffusion-weighted imaging (DWI) correlated with histopathology after neoadjuvant chemotherapy (NACT) in patients with locally advanced cervical cancer (LACC).

MATERIALS AND METHODS

Thirty-three patients with LACC were examined with 3T magnetic resonance imaging (MRI) with DWI and apparent diffusion coefficient (ADC) maps. MRIs were performed for each patient at three timepoints: before the first NACT, 2 weeks after the first NACT, and 2 weeks after the second NACT. Uterine cervical specimens were collected at the same timepoints. Specimens were stained for tumor cell density, proliferating cell nuclear antigen (PCNA), and aquaporin 1 (AQP1). Treatment responses were classified as the effective group (complete and partial response) and the ineffective group (stable and progressive disease).

RESULTS

The ADC value of the effective group after the first chemotherapy was higher than that before chemotherapy (P = 0.002), and expressions of three pathological indicators (tumor cell density, PCNA, and AQP1) significantly decreased after the first NACT compared with those prechemotherapy (P < 0.001). Changes of PCNA expression were negatively correlated with changes of ADC values after the first NACT in the effective group (r = -0.56, P = 0.03). Changes of cellular density were negatively correlated with changes of ADC values from the time of prechemotherapy to after the second NACT in the effective group (r = -0.51, P = 0.04).

CONCLUSION

The ADC change after successful chemotherapy is closely related with cellular characteristics preceding size reduction. ADC may be used as an early imaging biomarker of NACT response in LACC.

Aquaporin 3 knockdown suppresses tumour growth and angiogenesis in experimental non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is one of the most common diseases encountered in medical oncology practice. The aim of the present study was to test the antitumour effects of short-hairpin RNA targeting aquaporin 3 (AQP3) in experimental NSCLC. Expression of AQP3 was suppressed in human A549 and H1299 NSCLC cell lines by short-hairpin RNA-mediated silencing. Therapeutic effects were assessed by examining tumorigenicity using a subcutaneous xenograft mouse model of NSCLC. Aquaporin 3 knockdown inhibited tumour growth and prolonged survival of mice with tumours. Aquaporin 3 knockdown suppressed tumour proliferation, marked by enhanced expression of p53, an increased ratio of cleaved caspase 3 to pro-caspase 3 and reduced expression of proliferating cell nuclear antigen and B-cell lymphoma-2 (bcl-2). Aquaporin 3 knockdown inhibited tumour angiogenesis, marked by decreased CD31 immunostaining and reduced expression of hypoxia-inducible factor-2α and vascular endothelial growth factor. Aquaporin 3 knockdown reduced cellular glycerol content and suppressed mitochondrial ATP formation. Aquaporin 3 knockdown in vitro significantly suppressed activities of matrix metalloproteinases MMP2 and MMP9, reduced AKT phosphorylation and decreased cell invasiveness of A549 and H1299 cells. In conclusion, AQP3 knockdown suppressed tumour growth and reduced angiogenesis in human NSCLS xenografts. Aquaporin 3 could thus be envisaged as a novel therapeutic target for NSCLC.