Semaphorins and Their Receptors in Hematological Malignancies

Trends in childhood leukemia incidence in urban countries and their relation to environmental factors, including space weather

Leukemia is the most common cancer in children. Its incidence has been increasing worldwide since 1910th, suggesting the presence of common sources of the disease, most likely related to people's lifestyle and environment. Understanding the relationship between childhood leukemia and environmental conditions is critical to preventing the disease. This discussion article examines established potentially-carcinogenic environmental factors, such as vehicle emissions and fires, alongside space weather-related parameters like cosmic rays and the geomagnetic field. To discern the primary contributor, we analyze trends and annual variations in leukemia incidence among 0-14-year-olds in the United States, Canada, Australia, and Russia from 1990 to 2018. Comparisons are drawn with the number of vehicles (representing gasoline emissions) and fire-affected land areas (indicative of fire-related pollutants), with novel data for Russia introduced for the first time. While childhood leukemia incidence is rising in all countries under study, the rate of increase in Russia is twice that of other nations, possibly due to a delayed surge in the country's vehicle fleet compared to others. This trend in Russia may offer insights into past leukemia levels in the USA, Canada, and Australia. Our findings highlight vehicular emissions as the most substantial environmental hazard for children among the factors examined. We also advocate for the consideration of potential modulation of carcinogenic effects arising from variations in cosmic ray intensity, as well as the protective role of the geomagnetic field. To support the idea, we provide examples of potential space weather effects at both local and global scales. The additional analysis includes statistical data from 49 countries and underscores the significance of the magnetic field dip in the South Atlantic Anomaly in contributing to a peak in childhood leukemia incidence in Peru, Ecuador and Chile. We emphasize the importance of collectively assessing all potentially carcinogenic factors for the successful future predictions of childhood leukemia risk in each country.

Circulating Biomarkers Associated with the Diagnosis and Prognosis of B-Cell Progenitor Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is a hematological disease characterized by the dysfunction of the hematopoietic system that leads to arrest at a specific stage of stem cells development, suppressing the average production of cellular hematologic components. BCP-ALL is a neoplasm of the B-cell lineage progenitor. BCP-ALL is caused and perpetuated by several mechanisms that provide the disease with its tumor potential and genetic and cytological characteristics. These pathological features are used for diagnosis and the prognostication of BCP-ALL. However, most of these paraclinical tools can only be obtained by bone marrow aspiration, which, as it is an invasive study, can delay the diagnosis and follow-up of the disease, in addition to the anesthetic risk it entails for pediatric patients. For this reason, it is crucial to find noninvasive and accessible ways to supply information concerning diagnosis, prognosis, and the monitoring of the disease, such as circulating biomarkers. In oncology, a biomarker is any measurable indicator that demonstrates the presence of malignancy, tumoral behavior, prognosis, or responses to treatments. This review summarizes circulating molecules associated with BCP-ALL with potential diagnostic value, classificatory capacity during monitoring specific clinic features of the disease, and/or capacity to identify each BCP-ALL stage regarding its evolution and outcome of the patients with BCP-ALL. In the same way, we provide and classify biomarkers that may be used in further studies focused on clinical approaches or therapeutic target identification for BCP-ALL.

Plexins as Regulators of Cancer Cell Proliferation, Migration, and Invasivity

Plexins are a family of nine single-pass transmembrane receptors with a conserved GTPase activating protein (GAP) domain. The plexin family is divided into four subfamilies: Type-A, type-B, type-C, and type-D plexins. Plexins function as receptors for axon guidance factors of the semaphorin family. The semaphorin gene family contains 22 genes that are divided into eight subclasses of which subclasses three to seven represent vertebrate semaphorins. The plexins and their semaphorin ligands have important roles as regulators of angiogenesis, cancer proliferation, and metastasis. Class 3 semaphorins, with the exception of sema3E, are the only semaphorins that do not bind directly to plexins. In order to transduce their signals, they bind instead to complexes consisting of receptors of the neuropilin family and various plexins. Some plexins also form complexes with tyrosine-kinase receptors such as the epidermal growth factor receptor ErbB2, the mesenchymal epithelial transition factor receptor (MET), and the Vascular endothelial growth factor receptor 2 (VEGFR2) and, as a result, can modulate cell proliferation and tumor progression. This review focuses on the roles of the different plexins in the control of cancer cell proliferation and invasiveness. Plexins also affect tumor progression and tumor metastasis by indirect mechanisms, such as modulation of angiogenesis and immune responses. However, these topics are not covered in the present review.

mRNA-lncRNA gene expression signature for predicting pediatric AML relapse

Children with acute myeloid leukemia (AML) face a relapse of the disease in 30% of all cases. AML relapse is difficult to predict, and existing risk scales are often ineffective. Using data from the Therapeutically Applicable Research to Generate Effective Treatments (TARGET-AML) project, we defined an expression signature based on matrix RNAs (mRNAs) and long non-coding RNAs (lncRNAs) that could predict relapse in pediatric AML patients. We used a comprehensive bioinformatics analysis that included the identification of functionally significant differentially expressed genes in AML relapse, several rounds of association with relapse-free survival (RFS) mRNAs and lncRNAs selection, and evaluation of the obtained expression signatures to predict recurrence at the primary tumor level. Two mRNAs (ENSG00000149289.11 (ZC3H12C) and ENSG00000075213.11 (SEMA3A)) and one lncRNA (ENSG00000287569.1) were associated with a decreased RFS. Models including changes in the expression of ZC3H12C and ENSG00000287569.1, as well as all three markers, demonstrated very good quality and could predict the recurrence of pediatric AML.

Advances in SEMA3F regulation of clinically high-incidence cancers

Cancer has become a leading cause of morbidity and mortality in recent years. Its high prevalence has had a severe impact on society. Researchers have achieved fruitful results in the causative factors, pathogenesis, treatment strategies, and cancer prevention. Semaphorin 3F (SEMA3F), a member of the signaling family, was initially reported in the literature to inhibit the growth, invasion, and metastasis of cancer cells in lung cancer. Later studies showed it has cancer-inhibiting effects in malignant tumors such as breast, colorectal, ovarian, oral squamous cell carcinoma, melanoma, and head and neck squamous carcinoma. In contrast, recent studies have reported that SEMA3F is expressed more in hepatocellular carcinoma than in normal tissue and promotes metastasis of hepatocellular carcinoma. We chose lung, breast, colorectal, and hepatocellular carcinomas with high clinical prevalence to review the roles and molecular mechanisms of SEMA3F in these four carcinomas. We concluded with an outlook on clinical interventions for patients targeting SEMA3F.

The Role of Semaphorins and Their Receptors in Innate Immune Responses and Clinical Diseases of Acute Inflammation

Semaphorins are a group of proteins that have been studied extensively for their critical function in neuronal development. They have been shown to regulate airway development, tumorigenesis, autoimmune diseases, and the adaptive immune response. Notably, emerging literature describes the role of immunoregulatory semaphorins and their receptors, plexins and neuropilins, as modulators of innate immunity and diseases defined by acute injury to the kidneys, abdomen, heart and lungs. In this review we discuss the pathogenic functions of semaphorins in clinical conditions of acute inflammation, including sepsis and acute lung injury, with a focus on regulation of the innate immune response as well as potential future therapeutic targeting.

Semaphorin 4D is a potential biomarker in pediatric leukemia and promotes leukemogenesis by activating PI3K/AKT and ERK signaling pathways

Semaphorin 4D (Sema4D) is highly expressed in a variety of tumors and is associated with high invasion, poor prognosis and poor therapeutic response. However, the expression and role of Sema4D in leukemia remains unclear. The present study investigated the expression of Sema4D in pediatric leukemia and its effects in leukemia cells. The results demonstrated that Sema4D protein was highly expressed in peripheral blood mononuclear cells of patients with pediatric leukemia, and high levels of soluble Sema4D were also observed in the plasma of these patients. Sema4D knockdown induced cell cycle arrest in G₀/G₁ phase, inhibited proliferation and promoted apoptosis in BALL‑1 cells, while Sema4D overexpression exhibited the opposite effect. In Jurkat cells, Sema4D knockdown inhibited proliferation and promoted apoptosis, while Sema4D overexpression decreased the abundance of the cells in the G₀/G₁ phase of the cell cycle and promoted proliferation. Sema4D overexpression also increased the migratory capacity of Jurkat cells and the invasive capacity of BALL‑1 cells. The phosphorylation level of PI3K was decreased in both Sema4D knocked‑down Jurkat and BALL‑1 cells, and the phosphorylation level of ERK was decreased in Sema4D knocked‑down BALL‑1 cells. The phosphorylation levels of PI3K, ERK and AKT were elevated in patients with pediatric leukemia, and were correlated to the increased Sema4D expression. Sema4D overexpression was associated with a shorter overall survival in patients with acute myeloid leukemia. Overall, the results of the present study indicated that Sema4D serves an important role in leukemia development by activating PI3K/AKT and ERK signaling, and it may be used as a potential target for the diagnosis and treatment of leukemia.

Immunosuppressive Regulation of Dendritic Cells and T Cells in Allergic Rhinitis by Semaphorin 3A

BACKGROUND

Semaphrin3A (Sema3A) was found to play a major role in immune regulation in autoimmune diseases and to be of importance in allergic disease. However, the effect of Sema3A on allergic rhinitis (AR) is not fully clear.

OBJECTIVE

We sought to elucidate the effects of Sema3A on the regulation of dendritic cells (DCs) and naive CD4⁺ T cells in AR.

METHODS

The expression of Sema3A in nasal mucosa was measured by immunohistochemical staining and western blotting. Human peripheral blood mononuclear cells were separated by the Ficoll-Hypaque method. DCs and naive CD4⁺ T cells were purified by magnetic selection. A human Sema3A Fc chimera was added to DCs and naive CD4⁺ T cells in vitro to evaluate the effect of Sema3A on the function of DCs and T cells. Labeling T cells with CFSE was used to determine cell proliferation. Flow cytometry was used to detect the DC maturation markers (CD40 and CD83) and T helper 17 (Th17) and regulatory T cell (Treg) percentages. ELISA was used to detect the IL10, IL17, IL4, and IFNγ cytokine levels.

RESULTS

The expression of Sema3A in AR inferior turbinate tissue was lower than that in healthy control tissue. Compared with healthy control DCs, AR DCs showed decreased levels of the DC maturation markers CD40 and CD83 after Sema3A treatment. Furthermore, Sema3A decreased naive CD4⁺ T cell proliferation in AR. In addition, Sema3A increased the percentage of Tregs but had no obvious effect on Th17 cells. Moreover, Sema3A significantly increased levels of IL10 and IFNγ, and decreased level of IL4, but had no obvious effect on level of IL17.

CONCLUSION

AR presented with low expression of Sema3A in nasal mucosa, and Sema3A could decrease DC maturation, T cell proliferation, and Treg polarization.

Semaphorin 4D is a potential biomarker in pediatric leukemia and promotes leukemogenesis by activating PI3K/AKT and ERK signaling pathways

Semaphorin 4D (Sema4D) is highly expressed in a variety of tumors and is associated with high invasion, poor prognosis and poor therapeutic response. However, the expression and role of Sema4D in leukemia remains unclear. The present study investigated the expression of Sema4D in pediatric leukemia and its effects in leukemia cells. The results demonstrated that Sema4D protein was highly expressed in peripheral blood mononuclear cells of patients with pediatric leukemia, and high levels of soluble Sema4D were also observed in the plasma of these patients. Sema4D knockdown induced cell cycle arrest in G₀/G₁ phase, inhibited proliferation and promoted apoptosis in BALL-1 cells, while Sema4D overexpression exhibited the opposite effect. In Jurkat cells, Sema4D knockdown inhibited proliferation and promoted apoptosis, while Sema4D overexpression decreased the abundance of the cells in the G₀/G₁ phase of the cell cycle and promoted proliferation. Sema4D overexpression also increased the migratory capacity of Jurkat cells and the invasive capacity of BALL-1 cells. The phosphorylation level of PI3K was decreased in both Sema4D knocked-down Jurkat and BALL-1 cells, and the phosphorylation level of ERK was decreased in Sema4D knocked-down BALL-1 cells. The phosphorylation levels of PI3K, ERK and AKT were elevated in patients with pediatric leukemia, and were correlated to the increased Sema4D expression. Sema4D overexpression was associated with a shorter overall survival in patients with acute myeloid leukemia. Overall, the results of the present study indicated that Sema4D serves an important role in leukemia development by activating PI3K/AKT and ERK signaling, and it may be used as a potential target for the diagnosis and treatment of leukemia.

Semaphorins as emerging clinical biomarkers and therapeutic targets in cancer

Semaphorins are a large family of developmental regulatory signals, characterized by aberrant expression in human cancers. These molecules crucially control cell-cell communication, cell migration, invasion and metastasis, tumor angiogenesis, inflammatory and anti-cancer immune responses. Semaphorins comprise secreted and cell surface-exposed molecules and their receptors are mainly found in the Plexin and Neuropilin families, which are further implicated in a signaling network controlling the tumor microenvironment. Accumulating evidence indicates that semaphorins may be considered as novel clinical biomarkers for cancer, especially for the prediction of patient survival and responsiveness to therapy. Moreover, preclinical experimental studies have demonstrated that targeting semaphorin signaling can interfere with tumor growth and/or metastatic dissemination, suggesting their relevance as novel therapeutic targets in cancer; this has also prompted the development of semaphorin-interfering molecules for application in the clinic. Here we will survey, in diverse human cancers, the current knowledge about the relevance of semaphorin family members, and conceptualize potential lines of future research development in this field.

Immune semaphorins: Crucial regulatory signals and novel therapeutic targets in asthma and allergic diseases

Asthma and allergic diseases are a group of chronic inflammatory disorders that arise as a result of excessive responses of the immune system against intrinsically harmless environmental substances. It is well known that substantial joint characteristics exist between the immune and nervous systems. The semaphorins (Semas) were initially characterized as axon-guidance molecules that play a crucial role during the development of the nervous system. However, increasing evidence indicates that a subset of Semas, termed "immune Semas", acting through their cognate receptors, namely, plexins (Plxns), and neuropilins (Nrps), also contributes to both physiological and pathological responses of the immune system. Notably, immune Semas exert critical roles in regulating a broad spectrum of biological processes, including immune cell-cell interactions, activation, differentiation, cell migration and mobility, angiogenesis, tumor progression, as well as inflammatory responses. Accumulating evidence indicates that the modification in the signaling of immune Semas could lead to various immune-mediated inflammatory diseases, ranging from cancer to autoimmunity and allergies. This review summarizes the recent evidence regarding the role of immune Semas in the pathogenesis of asthma and allergic diseases and discusses their therapeutic potential for treating these diseases.

Semaphorin-4C is upregulated in epithelial ovarian cancer

The present retrospective study aimed to investigate the expression of semaphorin-4C (Sema4C) in epithelial ovarian cancer (EOC), and to determine the association between Sema4C expression and patient clinicopathological characteristics. Sema4C mRNA expression was detected by reverse transcription-quantitative polymerase chain reaction in the tissues of 74 cases of EOC, 20 cases of ovarian epithelial benign tumor, 20 cases of ovarian borderline epithelial tumor and 15 cases of normal ovarian tissue. Immunohistochemistry was used to detect the expression and localization of Sema4C. The association between Sema4C expression level and patients clinicopathological characteristics was determined by χ² test. The results demonstrated that Sema4C expression level in ovarian epithelial carcinoma tissues was significantly higher compared with that in benign tumors, borderline epithelial tumors and normal ovarian tissues (P<0.05). In addition, Sema4C expression in ovarian cancer tissues was significantly associated with the clinical and pathological stages of tumors (P<0.05). In conclusion, the present study demonstrated that Sema4C expression was upregulated in EOC.