PLCE1 as a diagnostic and prognostic biomarker by promoting the growth and progression of oral squamous cell carcinoma

OBJECTIVE

This study aimed to explore the role of phospholipase C epsilon1 (PLCE1) in the growth and progression of oral squamous cell carcinoma (OSCC) and determine its potential as a biomarker with respect to diagnosis, prognosis and treatment of OSCC.

METHODS

The expression level of PLCE1 in tissue specimens was detected by immunohistochemistry (182 OSCC cases and 76 controls) and its relationship to clinicopathological parameters was analyzed. Then, the diagnostic value of PLCE1 in OSCC was verified by constructing the receiver operating characteristic (ROC) curve. Kaplan-Meier and Cox analysis were performed to investigate the role of PLCE1 in predicting the prognosis of OSCC patients. Furthermore, the effects of PLCE1 on the occurrence and development of OSCC were revealed by knocking down the level of PLCE1.

RESULTS

PLCE1 was mainly located in the cytoplasm of OSCC cells, and its level in OSCC tissues was obviously higher than in adjacent normal tissues. While the expression of PLCE1 did not correlate with clinicopathological parameters of OSCC. The area under the ROC curve (AUC) of PLCE1 was 0.865 with a sensitivity of 75.8% and a specificity of 78.8%. Besides, high expression of PLCE1 suggested a worse prognosis in OSCC patients than those with low expression. The knockdown of PLCE1 obviously inhibited proliferation, migration, and invasion of OSCC cells, and induce G0 cell cycle phase arrest and apoptosis, thus preventing the progression of OSCC.

CONCLUSION

PLCE1 may cause carcinogenesis and development of OSCC, which provide a novel possibility in diagnosis, prognosis and treatment of OSCC. This article is protected by copyright. All rights reserved.

PLCE1 Polymorphisms Are Associated With Gastric Cancer Risk: The Changes in Protein Spatial Structure May Play a Potential Role

Background

Gastric cancer (GC) is one of the most significant health problems worldwide. Some studies have reported associations between Phospholipase C epsilon 1 (PLCE1) single-nucleotide polymorphisms (SNPs) and GC susceptibility, but its relationship with GC prognosis lacked exploration, and the specific mechanisms were not elaborated fully yet. This study aimed to further explore the possible mechanism of the association between PLCE1 polymorphisms and GC.

Materials and Methods

A case-control study, including 588 GC patients and 703 healthy controls among the Chinese Han population, was performed to investigate the association between SNPs of PLCE1 and GC risk by logistic regression in multiple genetic models. The prognostic value of PLCE1 in GC was evaluated by the Kaplan-Meier plotter. To explored the potential functions of PLCE1, various bioinformatics analyses were conducted. Furthermore, we also constructed the spatial structure of PLCE1 protein using the homology modeling method to analyze its mutations.

Results

Rs3765524 C > T, rs2274223 A > G and rs3781264 T > C in PLCE1 were associated with the increased risk of GC. The overall survival and progression-free survival of patients with high expression of PLCE1 were significantly lower than those with low expression [HR (95% CI) = 1.38 (1.1–1.63), P < 0.01; HR (95% CI) = 1.4 (1.07–1.84), P = 0.01]. Bioinformatic analysis revealed that PLCE1 was associated with protein phosphorylation and played a crucial role in the calcium signal pathway. Two important functional domains, catalytic binding pocket and calcium ion binding pocket, were found by homology modeling of PLCE1 protein; rs3765524 polymorphism could change the efficiency of the former, and rs2274223 polymorphism affected the activity of the latter, which may together play a potentially significant role in the tumorigenesis and prognosis of GC.

Conclusion

Patients with high expression of PLCE1 had a poor prognosis in GC, and SNPs in PLCE1 were associated with GC risk, which might be related to the changes in spatial structure of the protein, especially the variation of the efficiency of PLCE1 in the calcium signal pathway.

Phospholipase C Beta 2 Protein Overexpression Is a Favorable Prognostic Indicator in Newly Diagnosed Normal Karyotype Acute Myeloid Leukemia

Phospholipase C beta 2 (PLC-β2) regulates various essential functions in cell signaling, differentiation, growth, and mobility. We investigated the clinical implications of PLC-β2 protein expression in newly diagnosed normal karyotype acute myeloid leukemia (NK-AML). The PLC-β2 expression status in bone marrow tissues obtained from 101 patients with NK-AML was determined using semiquantitative immunohistochemistry (IHC). IHC results were compared with those for known prognostic markers. Using a cutoff score for positivity of 7.0, the PLC-β2 overexpression group showed superior overall survival (OS) (72.6% vs. 26.5%; P=0.016) and low hazard ratio (HR) (0.453; P=0.019) compared with the PLC-β2 low-expression group. The PLC-β2 overexpression group showed no significant gain in event-free survival (50.6% vs. 43.0%, P=0.465) and HR (0.735; P=0.464). Among the known prognostic markers, only FLT3-ITD positivity was associated with a significantly low OS and high HR. In conclusion, PLC-β2 overexpression was associated with favorable OS in NK-AML patients. Our results suggest that PLC-β2 expression assessment using IHC allows prognosis prediction in NK-AML.

Immunomodulatory regulation by heat-labile enterotoxins and potential therapeutic applications

Introduction: Heat-labile enterotoxins (HLTs) and their cognate ganglioside receptors have been extensively studied because of their therapeutic potential. Gangliosides play arole in modulating effector cells of the immune system, and HLTs provide a novel means for stimulating ganglioside-mediated responses in immunocompetent cells.Areas covered: To evaluate the mechanisms of HLT adjuvanticity, a systemic literature review was performed using relevant keyword searches of the PubMed database, accessing literature published as recently as late 2020. Since HLTs bind to specific ganglioside receptors on immunocytes, they can act as regulators via stimulation or tapering of immune responses from associated signal transduction events. Binding of HLTs to gangliosides can increase proliferation of T-cells, increase cytokine release, augment mucosal/systemic antibody responses, and increase the effectiveness of antigen presenting cells. Subunit components also independently stimulate certain immune responses. Mutant forms of HLTs have potent immunomodulatory effects without the toxicity associated with holotoxins.Expert opinion: HLTs have been the subject of abundant research exploring their use as vaccine adjuvants, in the treatment of autoimmune conditions, in cancer therapy, and for weight loss, proving that these molecules are promising tools in the field of immunotherapy.

Evaluation of Ficolin-3 as a Potential Prognostic Serum Biomarker in Chinese Patients with Esophageal Cancer

Aims: Ficolin-3 is a circulating pattern recognition molecule of the lectin pathway, which participates in the host immune responses to cancer. Our study aimed to evaluate the prognostic efficacy of ficolin-3 in patients with esophageal cancer (EC). Methods: A total of 233 patients with EC were recruited for this study during a period from March 2013 to March 2016. Clinical information and pretherapeutic tumor specimens from all of the patients were analyzed. Serum ficolin-3 levels were determined by enzyme-linked immunosorbent assay. Patients were then assigned into quartiles according to their serum ficolin-3 levels. The Cox proportional hazards model was utilized to explore the correlation between ficolin-3 levels with overall survival (OS) and disease-specific survival (DSS). Results: The serum ficolin-3 level in the esophageal squamous cell carcinoma (ESCC) group was significantly higher than in the esophageal adenocarcinoma (EAC) group (19.59 ± 4.35 ng/mL vs. 18.39 ± 5.42 ng/mL, p < 0.01). There were great differences in prevalence of ESCC, tumor length, involvement of adventitia, and lymph node status among patients in different ficolin-3 groups (all p < 0.01). Both univariate analyses and further multivariate analyses revealed the close association between ficolin-3 levels and EAC (For OS and DSS, all p < 0.05). Out of 233 patients, survival information was available for 220, including 100 (45.45%) females and 120 (54.54%) males. When dividing the ficolin-3 levels into quartiles, patients with higher serum ficolin-3 levels showed a trend toward longer OS and DSS no matter whether they were diagnosed as ESCC or EAC (HR 0.21-0.55, all p < 0.05). Conclusions: Serum ficolin-3 levels were identified as an independent prognostic biomarker for DSS and OS in Chinese patients with EC, especially EAC.

An epigenomic approach to identifying differential overlapping and cis-acting lncRNAs in cisplatin-resistant cancer cells

Long noncoding RNAs (lncRNAs) are critical regulators of cell biology whose alteration can lead to the development of diseases such as cancer. The potential role of lncRNAs and their epigenetic regulation in response to platinum treatment are largely unknown. We analyzed four paired cisplatin-sensitive/resistant non-small cell lung cancer and ovarian cancer cell lines. The epigenetic landscape of overlapping and cis-acting lncRNAs was determined by combining human microarray data on 30,586 lncRNAs and 20,109 protein coding mRNAs with whole-genome bisulfite sequencing. Selected candidate lncRNAs were further characterized by PCR, gene-ontology analysis, and targeted bisulfite sequencing. Differential expression in response to therapy was observed more frequently in cis-acting than in overlapping lncRNAs (78% vs. 22%, fold change ≥1.5), while significantly altered methylation profiles were more commonly associated with overlapping lncRNAs (29% vs. 8%; P value <0.001). Moreover, overlapping lncRNAs contain more CpG islands (CGIs) (25% vs. 17%) and the majority of CGI-containing overlapping lncRNAs share these CGIs with their associated coding genes (84%). The differences in expression between sensitive and resistant cell lines were replicated in 87% of the selected candidates (P<0.05), while our bioinformatics approach identifying differential methylation was confirmed in all of the selected lncRNAs (100%). Five lncRNAs under epigenetic regulation appear to be involved in cisplatin resistance (AC091814.2, AC141928.1, RP11-65J3.1-002, BX641110, and AF198444). These novel findings provide new insights into epigenetic mechanisms and acquired resistance to cisplatin that highlight specific lncRNAs, some with unknown function, that may signal strategies in epigenetic therapies.

Genetic variants in gastric cancer: Risks and clinical implications

Cancer is a multifactorial disease that involves many molecular alterations. Gastric cancer (GC) is the third leading cause of cancer death worldwide. GC is a highly heterogeneous disease with different molecular and genetics features. Therefore, this review focuses on an overview of the genetic aspects of gastric cancer by highlighting the important impact and role of deletions and/or duplications of chromosomal segments, genomic variants, H. pylori infection and interleukin variants, as found in gene expression and newly proposed molecular classification studies. The challenge is to better understand the mechanisms and different pathways that lead to the development and progression of GC.

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.

The Association Between Urinary Cadmium Levels and Dietary Habits with Risk of Gastrointestinal Cancer in Tabriz, Northwest of Iran

Cadmium (Cd) is a widespread toxic heavy metal and has long biological half-life. It has potential carcinogenic effects on multiple organ systems of human. However, no studies have evaluated the adverse effects of cadmium on incidence of cancer in gastrointestinal tract. The aim of this study was to investigate the association between urine cadmium (U-Cd) levels and risk of gastrointestinal cancer. This descriptive study was accomplished on 111 GI cancer patients as cases and 111 healthy people as control subjects from January to October in Tabriz, northwest Iran, during 2013. Cadmium in urine samples was measured by graphite furnace atomic absorption spectrophotometer (GFAAS). GI cancer patients had higher urine cadmium levels in comparison to healthy individuals (p < 0.05). The multivariate regression model manifested a significant association between the U-Cd concentrations and the risk of GI cancer (odds ratio (OR) = 1.70, 95 % CI = 1.35-2.20). Cases were 70 % more than controls at risk of cancer incidence. Our data indicates an association between U-Cd levels and GI cancer risk.

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.

Generation of metastatic melanoma specific antibodies by affinity purification

Melanoma is the most aggressive type of skin cancer and one of the most frequent tumours in young adults. Identification of primary tumours prone to develop metastasis is of paramount importance for further patient stratification. However, till today, no markers exist that are routinely used to predict melanoma progression. To ameliorate this problem, we generated antiserum directed against metastatic melanoma tissue lysate and applied a novel approach to purify the obtained serum via consecutive affinity chromatography steps. The established antibody, termed MHA-3, showed high reactivity against metastatic melanoma cell lines both in vitro and in vivo. We also tested MHA-3 on 227 melanoma patient samples and compared staining with the melanoma marker S100b. Importantly, MHA-3 was able to differentiate between metastatic and non-metastatic melanoma samples. By proteome analysis we identified 18 distinct antigens bound by MHA-3. Combined expression profiling of all identified proteins revealed a significant survival difference in melanoma patients. In conclusion, we developed a polyclonal antibody, which is able to detect metastatic melanoma on paraffin embedded sections. Hence, we propose that this antibody will represent a valuable additional tool for precise melanoma diagnosis.