Involvement of the PLCε/PKCα pathway in human BIU-87 bladder cancer cell proliferation

MicroRNA-34 and gastrointestinal cancers: a player with big functions

It is commonly assumed that gastrointestinal cancer is the most common form of cancer across the globe and is the leading contributor to cancer-related death. The intricate mechanisms underlying the growth of GI cancers have been identified. It is worth mentioning that both non-coding RNAs (ncRNAs) and certain types of RNA, such as circular RNAs (circRNAs), long non-coding RNAs (lncRNAs), and microRNAs (miRNAs), can have considerable impact on the development of gastrointestinal (GI) cancers. As a tumour suppressor, in the group of short non-coding regulatory RNAs is miR-34a. miR-34a silences multiple proto-oncogenes at the post-transcriptional stage by targeting them, which inhibits all physiologically relevant cell proliferation pathways. However, it has been discovered that deregulation of miR-34a plays important roles in the growth of tumors and the development of cancer, including invasion, metastasis, and the tumor-associated epithelial-mesenchymal transition (EMT). Further understanding of miR-34a's molecular pathways in cancer is also necessary for the development of precise diagnoses and effective treatments. We outlined the most recent research on miR-34a functions in GI cancers in this review. Additionally, we emphasize the significance of exosomal miR-34 in gastrointestinal cancers.

Phospholipase PLCE1 Promotes Transcription and Phosphorylation of MCM7 to Drive Tumor Progression in Esophageal Cancer

Phospholipase C epsilon 1 (PLCE1) is a well-established susceptibility gene for esophageal squamous cell carcinoma (ESCC). Identification of the underlying mechanism(s) regulated by PLCE1 could lead to a better understanding of ESCC tumorigenesis. In this study, we found that PLCE1 enhances tumor progression by regulating the replicative helicase MCM7 via two pathways. PLCE1 activated PKCα-mediated phosphorylation of E2F1, which led to the transcriptional activation of MCM7 and miR-106b-5p. The increased expression of miR-106b-5p, located in intron 13 of MCM7, suppressed autophagy and apoptosis by targeting Beclin-1 and RBL2, respectively. Moreover, MCM7 cooperated with the miR-106b-25 cluster to promote PLCE1-dependent cell-cycle progression both in vivo and in vitro. In addition, PLCE1 potentiated the phosphorylation of MCM7 at six threonine residues by the atypical kinase RIOK2, which promoted MCM complex assembly, chromatin loading, and cell-cycle progression. Inhibition of PLCE1 or RIOK2 hampered MCM7-mediated DNA replication, resulting in G1-S arrest. Furthermore, MCM7 overexpression in ESCC correlated with poor patient survival. Overall, these findings provide insights into the role of PLCE1 as an oncogenic regulator, a promising prognostic biomarker, and a potential therapeutic target in ESCC.

SIGNIFICANCE

PLCE1 promotes tumor progression in ESCC by activating PKCα-mediated phosphorylation of E2F1 to upregulate MCM7 and miR-106b-5p expression and by potentiating MCM7 phosphorylation by RIOK2.

Protein Kinase C (PKC) Isozymes as Diagnostic and Prognostic Biomarkers and Therapeutic Targets for Cancer

Protein kinase C (PKC) is a large family of calcium- and phospholipid-dependent serine/threonine kinases that consists of at least 11 isozymes. Based on their structural characteristics and mode of activation, the PKC family is classified into three subfamilies: conventional or classic (cPKCs; α, βI, βII, and γ), novel or non-classic (nPKCs; δ, ε, η, and θ), and atypical (aPKCs; ζ, ι, and λ) (PKCλ is the mouse homolog of PKCι) PKC isozymes. PKC isozymes play important roles in proliferation, differentiation, survival, migration, invasion, apoptosis, and anticancer drug resistance in cancer cells. Several studies have shown a positive relationship between PKC isozymes and poor disease-free survival, poor survival following anticancer drug treatment, and increased recurrence. Furthermore, a higher level of PKC activation has been reported in cancer tissues compared to that in normal tissues. These data suggest that PKC isozymes represent potential diagnostic and prognostic biomarkers and therapeutic targets for cancer. This review summarizes the current knowledge and discusses the potential of PKC isozymes as biomarkers in the diagnosis, prognosis, and treatment of cancers.

Evidence that PKCα inhibition in Dalton's Lymphoma cells augments cell cycle arrest and mitochondrial-dependent apoptosis

Protein kinase Cα (PKCα), belonging to ser/thr protein kinase, perform various biological functions. Overexpression of PKCα has been observed in multiple human malignancies including lymphoma. However, the molecular pathogenesis and involvement of PKCα in Non-Hodgkin lymphoma (NHL) are not clearly understood. Hence, deciphering the role of PKCα in NHL management may provide a better therapeutic option. In the present study, we used selective pharmacological inhibitors Gö6976 and Ro320432 that potentially inhibit PKCα-mediated signaling in DL cells, resulting in the inhibition of cell growth and mitochondrial-dependent apoptosis. PKCα inhibition by these inhibitors also displays cell cycle arrest at the G1 phase and causes growth retardation of DL cells. Our results extended the mechanism of PKCα in NHL, and provided potential implications for its therapy.

The Role of Calcium Signaling in Regulation of Epithelial-Mesenchymal Transition

Despite substantial advances in the field of cancer therapeutics, metastasis is a significant challenge for a favorable clinical outcome. Epithelial to mesenchymal transition (EMT) is a process of acquiring increased motility, invasiveness, and therapeutic resistance by cancer cells for their sustained growth and survival. A plethora of intrinsic mechanisms and extrinsic microenvironmental factors drive the process of cancer metastasis. Calcium (Ca2+) signaling plays a critical role in dictating the adaptive metastatic cell behavior comprising of cell migration, invasion, angiogenesis, and intravasation. By modulating EMT, Ca2+ signaling can regulate the complexity and dynamics of events leading to metastasis. This review summarizes the role of Ca2+ signal remodeling in the regulation of EMT and metastasis in cancer.

Oncogene PLCE1 may be a diagnostic biomarker and prognostic biomarker by influencing cell cycle, proliferation, migration, and invasion ability in hepatocellular carcinoma cell lines

Hepatocellular carcinoma (HCC) is a lethal malignancy worldwide. HCC has traits of late diagnosis and high recurrence. This study explored potential diagnosis and prognosis significance of phospholipase C epsilon 1 (PLCE1) in HCC. The messenger RNA (mRNA) levels and diagnostic value of PLCE1 were determined by real-time polymerase chain reaction and online databases GEPIA, oncomine, and GSE14520 data set. Survival analysis used the Kaplan-Meier Plotter website. Cell cycle, proliferation, migration, and invasion assays were performed with downregulated PLCE1 expression in HCC-M and HepG2 cell lines. PLCE1 was differentially expressed and highly expressed in tumors and had low expression in nontumor tissues (all p < .05). The diagnostic value of PLCE1 was validated with the datasets (all p < .01, all areas under curves > 0.7). PLCE1 mRNA expression was associated with the overall and relapse-free survival (both p < .05). Functional experiments indicated that downregulation of PLCE1 expression led to increased G1 stage in cell cycle and decreased cell proliferation, migration, and invasion compared with a negative control group (all p ≤ .05). The oncogene PLCE1 was differentially expressed in HCC and non-HCC tissues. It is a candidate for diagnosis and serves as prognosis biomarker. PLCE1 influenced survival by affecting the cell cycle, proliferation, migration, and invasion ability.

PLCε promotes urinary bladder cancer cells proliferation through STAT3/LDHA pathway‑mediated glycolysis

Phospholipase Cε (PLCε) and anaerobic glycolysis were determined to be involved in the development of human urinary bladder cancer (UBC), but the mechanisms remain unclear. In the present study, 64 bladder cancer specimens and 42 adjacent tissue specimens were obtained from 64 patients, and immunochemistry indicated that PLCε and lactate dehydrogenase (LDHA) are overexpressed in UBC. PLCε and LDHA were demonstrated to be positively correlated at transcription levels, indicating that one of these two genes may be regulated by another. To elucidate the mechanisms, PLCε was knocked down in T24 cells by short hairpin RNA, and then signal transducer and activator of transcription 3 (STAT3) phosphorylation and LDHA were determined to be downregulated, which indicated that PLCε may serve roles upstream of LDHA through STAT3 to regulate glycolysis in UBC. Furthermore, chromatin immunoprecipitation and luciferase reporter assays were performed to confirm that STAT3 could bind to the promoter of the LDHA gene to enhance its expression. A xenograft tumor mouse model also demonstrated similar results as the in vitro experiments, further confirming the role of PLCε in regulating bladder cell growth in vivo. Collectively, the present study demonstrated that PLCε may regulate glycolysis through the STAT3/LDHA pathway to take part in the development of human UBC.

Lidocaine enhances the effects of chemotherapeutic drugs against bladder cancer

This study aimed to investigate whether lidocaine, alone or in combination with other chemotherapeutic agents, inhibits the growth of human bladder cancer cells in vitro and orthotopically transplanted bladder tumors in vivo. The effects of lidocaine (1.25, 2.5 or 5 mg/mL), mitomycin C (MMC, 0.66 mg/mL), pirarubicin (0.75 mg/mL) and Su Fu’ning lotion (SFN, 0.0625 mg/mL) on the proliferation of human bladder cancer (BIU-87) cells were studied using the MTT assay. A Balb/c nude mouse model of bladder cancer was developed by orthotopic transplantation of BIU-87 cells, and the effects of intravesical instillation of lidocaine and MMC on bladder wet weight (a measure of tumor size) and survival (over 60 days) were studied. Lidocaine inhibited proliferation of BIU-87 cells in a concentration-dependent manner and (when given in combination) enhanced the actions of each of the other antiproliferative agents. In tumor-bearing mice, MMC alone had no effect on mean survival or bladder wet weight. However, the combination of 0.66 mg/mL MMC and 5 mg/mL lidocaine prolonged survival (from 34.62 ± 6.49 to 49.30 ± 6.72 days; n = 8, P < 0.05) and reduced bladder wet weight (from 68.94 ± 53.61 to 20.26 ± 6.07; n = 8, P < 0.05). Intravesical instillation of lidocaine combined with other chemotherapeutic agents potentially could be an effective therapy for bladder cancer.

Comprehensive bioinformatics analysis of the mRNA profile of PLCE1 knockdown in esophageal squamous cell carcinoma

The authors previously reported that Phospholipase C epsilon 1 (PLCE1) exacerbated esophageal squamous cell carcinoma (ESCC), however, the underlying mechanism remains to be fully elucidated. The present study aimed to identify key differentially expressed genes (DEGs) and signaling pathways regulated by PLCE1 in ESCC. EC9706 and Eca109 cell lines were transfected with the specific small interfering (si) RNA of PLCE1, reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) and western blotting were performed to detect the expression levels of PLCE1, and subsequently, mRNA array and multiple bioinformatics analysis were conducted. RT‑qPCR was used to verify gene expression array results. The findings of the present study indicated that PLCE1 mRNA and protein expression were significantly suppressed (P<0.05) in the PLCE1 siRNA‑transfected cells. In addition, a total of 223 DEGs with >2‑fold alterations were screened between the PLCE1 siRNA‑treated cells, including 168 upregulated and 53 downregulated DEGs. In particular, inflammation or immune‑associated molecules, including Toll‑like receptor (TLR)‑4 interleukin‑6, ‑8 and chemokine C‑X‑C motif ligand 2 were significantly increased following PLCE1 knockdown. Furthermore, Gene Ontology enrichment revealed terms associated with cell proliferation, differentiation, apoptosis, signal transduction, invasion and metastasis, which may potentially be associated with PLCE1 function. Kyoto Encyclopedia of Genes and Genomes pathway analysis demonstrated 46 pathways were disturbed by DEGs, including focal adhesion, mitogen activated protein kinase, TLR, p53 and janus kinase/signal transducer and activator of transcription signaling pathways. The RT‑qPCR results for validation of the selected DEGs were consistent with that of the microarray data. Overall, the results of the multiple bioinformatic analysis contributes to a systematic understanding of the roles of PLCE1 in ESCC.

Phospholipase C ε-1 gene polymorphisms and prognosis of esophageal cancer patients from a high-incidence region in northern China

Recent genome-wide association studies identified susceptibility loci for esophageal squamous cell carcinoma (ESCC), the most common histological type of esophageal cancer, in the phospholipase C ε-1 gene (PLCE1). The aim of the present study was to investigate whether polymorphisms of PLCE1 were associated with the prognosis of ESCC patients in a high-incidence region of northern China. The PLCE1 rs2274223 A/G and rs11599672T/G single-nucleotide polymorphisms (SNPs) were genotyped by polymerase chain reaction-ligase detection reaction method in 207 ESCC patients with survival information. The mean age ± standard deviation of the 207 ESCC patients was 60.3±7.9 years. Sex, age, smoking status and family history of upper gastrointestinal cancer were not found to be associated with the survival time of ESCC patients. The mean survival time of rs2274223 SNP A/A, A/G and G/G genotype carriers were 42.9, 43.4 and 46.3 months, respectively; for rs11599672 SNP T/T, T/G and G/G genotype carriers the survival time were 42.8, 43.8 and 42.7 months, respectively. There was no significant difference in survival time among the ESCC patients with different genotypes of rs2274223 and rs11599672 SNPs. In conclusion, PLCE1 rs227423 and rs11599672 SNPs cannot be used as predictive markers for the survival of ESCC patients from a high-incidence region of northern China.

MicroRNA-34a functions as a tumor suppressor by directly targeting oncogenic PLCE1 in Kazakh esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the frequent malignant tumors with poor prognosis worldwide. Identifying the prognostic biomarkers and potential mechanisms of such tumors has attracted increasing interest in esophageal cancer biology. Our previous study showed that phospholipase C elipson 1 (PLCE1) expression is up-regulated and associated with disease progression in esophageal carcinoma. MicroRNAs (miRNAs) play vital roles in regulating its target gene expression. However, studies on miRNA-regulated PLCE1 expression and its cellular function are still very few. We found that miR-34a is significantly expressed lower in ESCC tissues. We further showed that PLCE1 is a direct functional target gene of miR-34a, and the functional roles of miR-34a in ESCC cell lines in vitro were also determined through gain- and loss-of-function analyses. Results revealed that miR-34a functions as a tumor suppressor by inhibiting the proliferation, migration, and EMT phenotype, as well as promoting apoptosis of ESCC cell lines. Moreover, PLCE1 is overexpressed in ESCC tumors and promotes tumorigenicity in vivo and vitro. PLCE1 expression is negatively correlated with miR-34a profiles in ESCC tissues. Our data suggest that miR-34a exerts its anti-cancer function by suppressing PLCE1. The newly identified miR-34a/PLCE1 axis partially illustrates the molecular mechanism of ESCC metastasis and represents a new candidate therapeutic target for ESCC treatment.

The controversial role of phospholipase C epsilon (PLCε) in cancer development and progression

The phospholipase C (PLC) enzymes are important regulators of membrane phospholipid metabolism. PLC proteins can be activated by the receptor tyrosine kinases (RTK) or G-protein coupled receptors (GPCR) in response to the different extracellular stimuli including hormones and growth factors. Activated PLC enzymes hydrolyze phosphoinositides to increase the intracellular level of Ca²⁺ and produce diacylglycerol, which are important mediators of the intracellular signaling transduction. PLC family includes 13 isozymes belonging to 6 subfamilies according to their domain structures and functions. Although importance of PLC enzymes for key cellular functions is well established, the PLC proteins belonging to the ε, ζ and η subfamilies were identified and characterized only during the last decade. As a largest known PLC protein, PLCε is involved in a variety of signaling pathways and controls different cellular properties. Nevertheless, its role in carcinogenesis remains elusive.

The aim of this review is to provide a comprehensive and up-to-date overview of the experimental and clinical data about the role of PLCε in the development and progression of the different types of human and experimental tumors.

Targeting oncogenic PLCE1 by miR-145 impairs tumor proliferation and metastasis of esophageal squamous cell carcinoma

Phospholipase C epsilon 1 (PLCE1) is a susceptibility gene in esophageal squamous cell carcinoma (ESCC). Nevertheless, the role of PLCE1 in ESCC tumorigenesis has not been elucidated. In this study, we determined the function of PLCE1 and its regulatory microRNA (miRNA) in ESCC. PLCE1 protein was excessively expressed in ESCC and precancerous lesions compared with that in normal tissues. High PLCE1 expression levels in ESCC were significantly linked with poor overall survival. Knockdown of PLCE1 promoted the apoptosis, cytokine-induced apoptosis, and sensitivity of cancer cells to chemotherapeutic drugs but abrogated the proliferation and EMT phenotype of ESCC in vitro. Notably, miR-145 was newly identified as a potent repressor of PLCE1 expression by directly targeting the 3′UTR of PLCE1. MiR-145 also inhibited cell proliferation, migration, and metastasis, as well as controlled the cytoskeleton dynamics of esophageal cancer. Moreover, miR-145 was expressed at low levels in a large cohort of patients with ESCC and was inversely correlated with PLCE1 protein expression in cancer cells and tissues. These findings demonstrate that PLCE1 functions as tumor promoter in ESCC and can be suppressed by miR-145 through inhibition of PLCE1 translation. Hence, delivery of PLCE1-targeting miR-145 is a potential therapeutic approach for esophageal cancer.

Knockout of phospholipase Cε attenuates N-butyl-N-(4-hydroxybutyl) nitrosamine-induced bladder tumorigenesis

Bladder cancer frequently shows mutational activation of the oncogene Ras, which is associated with bladder carcinogenesis. However, the signaling pathway downstream of Ras remains to be fully elucidated. N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN) is able to induce bladder cancer by driving the clonal expansion of initiated cells carrying the activated form of Ras. Phospholipase Cε (PLCε) is the main target of BBN, while the tumor promoting role of PLCε remains controversial. The present study examined the role of PLCε in BBN-induced bladder carcinogenesis of mice with genetically inactivated PLCε. Using light and electron microscopy, the present study demonstrated that PLCε^−/− mice were resistant to BBN-induced bladder carcinogenesis. Furthermore, it was demonstrated that cyclooxygenase 2 and vascular endothelial growth factor-A were affected by the PLCε background of the mice, suggesting that the role of PLCε in tumor promotion may be ascribed to augmentation of inflammatory responses and angiogenesis. These results indicated that PLCε is crucial for BBN-induced bladder carcinogenesis as well as signaling downstream of Ras, and that PLCε is a candidate molecular target for the development of anti-cancer drugs.

MiR-328 suppresses the survival of esophageal cancer cells by targeting PLCE1

Esophageal cancer (EC) is the sixth leading cause of death worldwide. Recent studies have highlighted the vital role of microRNAs (miRNAs) in EC development and diagnosis. In our study, qPCR analysis showed that miRNA-328 was expressed at significantly low levels in EC109 and EC9706 cells. The results also showed that overexpression of miR-328 by lentivirus-mediated gene transfer markedly inhibited cell proliferation and invasion, and enhanced apoptosis; whereas, inhibition of miR-328 significantly promoted cell proliferation and invasion, and suppressed apoptosis in EC109 and EC9706 cells. Dual-luciferase reporter assay confirmed that miR-328 directly targeted phospholipase C epsilon 1 (PLCE1) by binding to target sequences in the 3'-UTR. qPCR and Western blot analysis showed that the PLCE1 was overexpressed in EC109 and EC9706 cells. Additionally, we found that miR-328 overexpression decreased PLCE1 mRNA and protein levels, while miR-328 inhibition enhanced the PLCE1 expression. Further analysis showed that PLCE1 overexpression rescued the inhibitory effect of miR-328 on cell proliferation and invasion, and repressed the promotive effect of miR-328 on cell apoptosis. In conclusion, our results suggest that miR-328 suppresses the survival of EC cells by regulating PLCE1 expression, which might be a potential therapeutic method for EC.

Knockdown of PLCε inhibits inflammatory cytokine release via STAT3 phosphorylation in human bladder cancer cells

Phospholipase Cε (PLCε) is a multifunctional enzyme implicated in inflammatory functions. There are limited data, however, on how PLCε can alter inflammatory cytokine by affecting downstream pathways. Recent studies suggest that inflammation is likely to have an important role in transitional cell carcinoma of bladder (TCCB) and cancer disease progression. Here, we showed that PLCε and p-STAT3 expression were both elevated in TCCB tissues compared to adjacent tissues, and the increase of PLCε level was associated with the increase of p-STAT3 level. Then, knockdown of PLCε using adenovirus-shPLCε significantly decreased inflammatory cytokine (IL-6, TNF-α, IL-1β) expression and inflammation-associated gene (TLR4, MyD88, p-STAT3) expression. Furthermore, we demonstrated that PLCε knockdown blocked LPS-induced inflammatory cytokine and p-STAT3 expression. Additionally, we found that combined treatment of STAT3 inhibitor S3I-201 with adenovirus-shPLCε exhibited synergistic inhibitory effects on expression of p-STAT3. Our results suggested that STAT3 phosphorylation is involved in PLCε-mediated inflammatory cytokine release. Our research is of potential importance in drug development programs using PLCε as a therapeutic target for TCCB.

PLCε signaling in cancer

PURPOSE

As one of the members of the PLC family, the phosphoinositide-specific phospholipase Cε (PLCε) has been shown to play pivotal roles in multiple signal pathways and control a variety of cellular functions. A number of studies have shown that aberrant regulation of PLCε was involved in various types of animal and human cancer. However, the role of PLCε in cancer remains elusive. In this review, we provide an overview of the PLCε, especially its roles in multiple signal pathways, and summarize the recent findings that highlight the roles of PLCε in carcinogenesis and cancer progression, making an avenue to provide a novel therapeutic strategy for the treatment of cancer.

METHODS

A literature search mainly paying attention to the network of PLCε involved in tumorigenesis and development was performed in electronic databases.

RESULTS

PLCε plays a key role in medicating the development and progression of human cancers with highest potency to be a target of cancer prevention and treatment.

PLCε knockdown inhibits prostate cancer cell proliferation via suppression of Notch signalling and nuclear translocation of the androgen receptor

Phospholipase Cε (PLCε), a key regulator of diverse cellular functions, has been implicated in various malignancies. Indeed, PLCε functions include cell proliferation, apoptosis and malignant transformation. Here, we show that PLCε expression is elevated in prostate cancer (PCa) tissues compared to benign prostate tissues. Furthermore, PLCε depletion using an adenovirally delivered shRNA significantly decreased cell growth and colony formation, arresting the PC3 and LNCaP cell lines in the S phase of the cell cycle. We also observed that PLCε was significantly correlated with Notch1 and androgen receptor (AR). Additionally, we demonstrate that the activation of both the Notch and AR signalling pathways is involved in PLCε-mediated oncogenic effects in PCa. Our findings suggest that PLCε is a putative oncogene and prognostic marker, potentially representing a novel therapeutic target for PCa.

Protein Kinase C (PKC) Isozymes and Cancer

Protein kinase C (PKC) is a family of phospholipid-dependent serine/threonine kinases, which can be further classified into three PKC isozymes subfamilies: conventional or classic, novel or nonclassic, and atypical. PKC isozymes are known to be involved in cell proliferation, survival, invasion, migration, apoptosis, angiogenesis, and drug resistance. Because of their key roles in cell signaling, PKC isozymes also have the potential to be promising therapeutic targets for several diseases, such as cardiovascular diseases, immune and inflammatory diseases, neurological diseases, metabolic disorders, and multiple types of cancer. This review primarily focuses on the activation, mechanism, and function of PKC isozymes during cancer development and progression.

Nuclear factor-κB signaling pathway is involved in phospholipase Cε-regulated proliferation in human renal cell carcinoma cells

Phospholipase Cε (PLCε), a downstream effector of small GTPase superfamily, has been identified to play a crucial role in tumorigenesis. Previously, our studies have showed that PLCε promotes proliferation of renal cell carcinoma (RCC) cells. However, the molecular mechanisms by which PLCε enhances the survival phenotype of RCC cells are still not fully instructed. In the present study, we first demonstrated that PLCε was highly expressed and had a close correlation with Ki67 protein expression in RCC tissue samples. Further, we found that downregulation of PLCε expression repressed growth and induced apoptosis in RCC cells. In addition, we reported a mechanism by which knockdown of PLCε gene potently suppressed the nuclear factor kappa (NF-κB) signaling pathway through action on inhibitor of κB kinase. Moreover, silencing PLCε gene decreased vascular endothelial growth factor (VEGF) expression, which was a downstream growth factor of NF-κB signaling pathway. Finally, downregulation of VEGF was severely enhanced by treatment cells with NF-κB specific inhibitor BAY11-7028 in PLCε knockdown cells. Taken together, these findings suggest that PLCε promotes RCC cell growth via NF-κB-mediated upregulation of VEGF.

A new PKCα/β/TBX3/E-cadherin pathway is involved in PLCε-regulated invasion and migration in human bladder cancer cells

Although PLCε has been verified to enhance bladder cancer cell invasion, the signaling pathways responsible for this remain elusive. Protein kinase C (PKCα/β), which is involved in cancer development and progression, has been demonstrated to be activated by PLCε. However, the roles of PKCα/β in PLCε-mediated bladder carcinoma cell invasion and migration have not been clearly identified. In this study, to determine what role PKCα/β plays in PLCε-mediated bladder cancer cell invasion and migration, we silenced PLCε gene by adenovirus-shPLCε in T24 and BIU-87 cells and then revealed that it significantly inhibited cell migration and invasion. Further research indicated that cell bio-function of PLCε-regulated was related with PKCα/β activity. These in vitro findings were supported by data from bladder carcinoma patient samples. In 35 case bladder cancer tumor samples, PLCε-overexpressing tumors showed significantly higher positive rates of PKCα/β membrane immunohistochemistry staining than PLCε-low-expressing tumors. Mechanistically, study further showed that PLCε knockdown gene induced E-cadherin expression and decreased TBX3 expression, both of which were dependent on PKCα/β activity. In addition, we demonstrated that treatment cells with TBX3-specific shorting hairpin RNA (shRNA) up-regulated E-cadherin expression and inhibited cell invasion/migration. Moreover, in in vivo experiment, immunohistochemistry analysis of Ad-shPLCε-infected tumor tissue showed low expression levels of phospho-PKCα/β and TBX3 and high expression levels of E-cadherin compared with those of the control group. In summary, our findings uncover that PKCα/β is critical for PLCε-mediated cancer cell invasion and migration and provide valuable insights for current and future Ad-shPLCε and PKCα/β clinical trials.

Heterozygote of PLCE1 rs2274223 increases susceptibility to human papillomavirus infection in patients with esophageal carcinoma among the Kazakh populations

The involvement of human papillomavirus (HPV) in the carcinogenesis of esophageal squamous carcinoma remains undetermined. However, three genome-wide association studies of esophageal cancer have identified a shared susceptibility locus at 10q23 (rs2274223: A5780G) in phospholipase C epsilon 1 (PLCE1). The current study aims to present a comprehensive and novel spectrum about the HPV genotype distribution of esophageal carcinoma in Kazakhs and assess its association with PLCE1 polymorphisms. The HPV genotypes in 183 patients with esophageal cancer and 89 controls selected from the Kazakh population were evaluated using the HPV gene chip. The PLCE1 rs2274223 variant was genotyped in esophageal carcinoma patients by MALDI-ToF Mass Spectrometry. The presence of seven HPV genotypes in esophageal carcinoma tissues-including HPV 16, 18, 35, 52, 6, 11, 43-was significantly higher at 31.7% than those in controls at 9.0% (P < 0.001). Such presence was strongly associated with increased risk of esophageal carcinoma (OR 4.70; 95% CI 2.13-10.36). Among all HPV genotypes detected, HPV16 was the most common genotype identified (29.0%, OR 4.13; 95% CI 1.87-9.13), which is significantly associated with well-differentiated esophageal carcinoma (P = 0.037). HPV-positive patients were generally younger than HPV-negative patients (70.1% vs. 29.3%, P = 0.013). PLCE1 rs2274223 genotypes AG and AG/GG were significantly associated with HPV-positive patients with esophageal carcinoma (OR 2.05, 95% CI 1.03-4.08 and OR 1.98, 95% CI 1.02-3.84, respectively). These findings suggest that heterozygote of PLCE1 rs2274223 increases susceptibility to HPV infection in patients with esophageal carcinoma among the Kazakh populations.

Multiple polymorphisms within the PLCE1 are associated with esophageal cancer via promoting the gene expression in a Chinese Kazakh population

Although recent genome-wide association studies of esophageal squamous cell carcinoma (ESCC) identified a susceptibility locus in phospholipase C epsilon 1 (PLCE1) in Chinese Han populations, few studies further confirmed these findings in pure Kazakh population in which there are higher incidence and mortality of ESCC. Here, we investigated the potential associations between 19 SNPs of PLCE1 and susceptibility to ESCC in 222 cases and 326 controls from a pure ethnic population of Kazakh. Real-time PCR and immunohistochemistry were performed to detect the PLCE1 expression levels and evaluate their association with PLCE1 polymorphism. We found that only 4 SNPs (rs753724, rs11187842, rs2274223, and rs12263737) with moderate linkage disequilibrium (LD) confer significantly increased risk of ESCC, with the ORs ranging from 1.43 to 2.04, and there was a risk allele dose-dependent increase in ESCC risk (P-trend=0.043). Especially, the risk effects of rs2274223 were more evident in poor differentiation and advanced clinical stages of Kazakh ESCC. Additionally, the significantly lowest PLCE1 mRNA expression was found in the KYSE-150 cell line having no risk alleles compared with other three cell lines having risk alleles, and the normal tissues of both homozygous mutant type of PLCE1 rs12263737 and rs2274223 had a higher PLCE1 staining score than that of homozygous wild type. Our findings suggested that genetic variants in PLCE1 might serve as candidate markers for Kazakh ESCC susceptibility, and these LD variants might influence ESCC risk individually and jointly by promoting the messenger RNA and protein expression of the gene.

Overexpression of PLCE1 in Kazakh esophageal squamous cell carcinoma: implications in cancer metastasis and aggressiveness

Three recent large-scale genome-wide association studies (GWAS) in Chinese Han populations have identified an esophageal squamous cell carcinoma (ESCC) susceptibility locus within phospholipase C epsilon 1 (PLCE1) gene, which encodes a phospholipase involved in intracellular signaling. The expressed PLCE1 in ESCC, however, are inconsistent. This study examined PLCE1 expression by immunohistochemistry (IHC) from 110 ethnic Kazakh ESCC patients and 50 from adjacent normal esophageal tissues (NETs). The expressed PLCE1 was localized in cytoplasm, especially in the peripheral layers of cancer cell nests, which was significantly higher in tumors than in NETs (p < 0.001). Increased expression of PLCE1 was correlated with advanced tumor-node-metastasis (TNM) stages (p = 0.015) and lymph node metastasis (p = 0.003) in patients with ESCC. Of the 110 patients, we examined 50 paired ESCC tissues and corresponding NETs by quantitative RT-PCR (polymerase chain reaction) and the mean mRNA level of PLCE1 in ESCC was 1.85-fold higher compared with those in corresponding NETs (p = 0.0012). Meanwhile, 4 of 5 ESCC cell lines also showed elevated expression of PLCE1 mRNA. Furthermore, elevated expression of PLCE1 mRNA in Kazakh ESCC was associated with its immunoreactivity (ρ = 0.297, p = 0.040), lymph node metastasis (p < 0.001), and advanced TNM stages of ESCC (p = 0.013). To our knowledge, this study demonstrates for the first time that PLCE1 overexpression correlates with lymph node metastasis and advanced TNM stages of Kazakh ESCC, implicating a role of PLCE1 in cancer metastasis and aggressiveness in ethnic Kazakh patients with ESCC. Furthermore, the current findings may warrant investigations into whether inhibiting PLCE1 could be a strategy for targeted anticancer therapy particularly for Kazakh ESCC.