Research on the establishment of a TPM3 monoclonal stable transfected PANC-1 cell line and the experiment of the EMT occurrence in human pancreatic cancer

Research Advances in the Role of the Tropomyosin Family in Cancer

Cancer is one of the most difficult diseases for human beings to overcome. Its development is closely related to a variety of factors, and its specific mechanisms have been a hot research topic in the field of scientific research. The tropomyosin family (Tpm) is a group of proteins closely related to the cytoskeleton and actin, and recent studies have shown that they play an important role in various cancers, participating in a variety of biological activities, including cell proliferation, invasion, and migration, and have been used as biomarkers for various cancers. The purpose of this review is to explore the research progress of the Tpm family in tumorigenesis development, focusing on the molecular pathways associated with them and their relevant activities involved in tumors. PubMed and Web of Science databases were searched for relevant studies on the role of Tpms in tumorigenesis and development and the activities of Tpms involved in tumors. Data from the literature suggest that the Tpm family is involved in tumor cell proliferation and growth, tumor cell invasion and migration, tumor angiogenesis, tumor cell apoptosis, and immune infiltration of the tumor microenvironment, among other correlations. It can be used as a potential biomarker for early diagnosis, follow-up, and therapeutic response of some tumors. The Tpm family is involved in cancer in a close relationship with miRNAs and LncRNAs. Tpms are involved in tumor tissue invasion and migration as a key link. On this basis, TPM is frequently used as a biomarker for various cancers. However, the specific molecular mechanism of its involvement in cancer progression has not been explained clearly, which remains an important direction for future research.

TPM2 attenuates progression of prostate cancer by blocking PDLIM7-mediated nuclear translocation of YAP1

BACKGROUND

Prostate cancer (PCa) is a common malignant tumor of the genitourinary system. Clinical intervention in advanced PCa remains challenging. Tropomyosins 2 (TPM2) are actin-binding proteins and have been found as a biomarker candidate for certain cancers. However, no studies have explored the role of TPM2 in PCa and its regulatory mechanism.

METHODS

TPM2 expression was assessed in Gene Expression Omnibus (GEO) and the Cancer Genome Atlas (TCGA) PCa patient dataset. The effect of TPM2 on PCa progression was assessed in vitro and in vivo by quantifying proliferation, migration, invasion and tumor growth assays, and the mechanism of TPM2 in PCa progression was gradually revealed by Western blotting, immunoprecipitation, and immunofluorescence staining arrays.

RESULTS

TPM2 was found to be severely downregulated in tumor tissues of PCa patients compared with tumor-adjacent normal tissues. In vitro experiments revealed that TPM2 overexpression inhibited PCa cell proliferation, invasion and androgen-independent proliferation. Moreover, TPM2 overexpression inhibited the growth of subcutaneous xenograft tumors in vivo. Mechanistically, this effect was noted to be dependent on PDZ-binding motif of TPM2. TPM2 competed with YAP1 for binding to PDLIM7 through the PDZ-binding motif. The binding of TPM2 to PDLIM7 subsequently inhibited the nuclear transport function of PDLIM7 for YAP1. YAP1 sequestered in the cytoplasm phosphorylated at S127, resulting in its inactivation or degradation which in turn inhibited the expression of YAP1 downstream target genes.

CONCLUSIONS

This study investigated the role of TPM2, PDLIM7, and YAP1 in PCa progression and castration resistance. TPM2 attenuates progression of PCa by blocking PDLIM7-mediated nuclear translocation of YAP1. Accordingly, targeting the expression or functional modulation of TPM2, PDLIM7, or YAP1 has the potential to be an effective therapeutic approach to reduce PCa proliferation and prevent the progression of castration-resistant prostate cancer (CRPC).

PolyC-RNA-binding protein 1 (PCBP1) enhances tropomyosin 3 (TPM3) mRNA stability to promote the progression of esophageal squamous cell carcinoma

The molecular etiology of esophageal squamous cell carcinoma (ESCC) has not been fully elucidated. Understanding the molecular mechanisms and finding new therapeutic targets for ESCC are of crucial importance. PolyC-RNA-binding protein 1 (PCBP1) is an RNA-binding protein. Here, we found overexpressed PCBP1 in esophageal cancer tissues by quantitative polymerase chain reaction (qPCR) and western blotting analysis. PCBP1 knockdown significantly attenuated migratory and invasion abilities of ESCC cells. Mechanistically, PCBP1 bound directly to tropomyosin 3 (TPM3) mRNA, which was verified by RNA–protein immunoprecipitation (RIP) assay. PCBP1 knockdown markedly reduced messenger RNA (mRNA) levels of TPM3. After inhibiting intracellular mRNA synthesis with actinomycin D (ActD), it was found that PCBP1 knockdown contributed to a significant decrease in TPM3 mRNA degradation. Furthermore, PCBP1 promoted migration and invasion of EC cells by directly binding to the 3’UTR of TPM3 mRNA, increasing TPM3 mRNA stability. Taken together, PCBP1 acting as a pro-oncogenic factor enhances TPM3 mRNA stability by directly binding to the 3’UTR of TPM3 mRNA in esophageal squamous cell carcinoma. Our findings provide a new perspective for understanding the molecular mechanism of esophageal carcinogenesis, and PCBP1 is a promising therapeutic target.

Systematic Analysis of an Invasion-Related 3-Gene Signature and Its Validation as a Prognostic Model for Pancreatic Cancer

Background

Pancreatic adenocarcinoma (PAAD) is a malignant tumor of the digestive system that is associated with a poor prognosis in patients owing to its rapid progression and high invasiveness.

Methods

Ninety-seven invasive-related genes obtained from the CancerSEA database were clustered to obtain the molecular subtype of pancreatic cancer based on the RNA-sequencing (RNA-seq) data of The Cancer Genome Atlas (TCGA). The differentially expressed genes (DEGs) between subtypes were obtained using the limma package in R, and the multi-gene risk model based on DEGs was constructed by Lasso regression analysis. Independent datasets GSE57495 and GSE62452 were used to validate the prognostic value of the risk model. To further explore the expression of the hub genes, immunohistochemistry was performed on PAAD tissues obtained from a large cohort.

Results

The TCGA-PAAD samples were divided into two subtypes based on the expression of the invasion-related genes: C1 and C2. Most genes were overexpressed in the C1 subtype. The C1 subtype was mainly enriched in tumor-related signaling pathways, and the prognosis of patients with the C1 subtype was significantly worse than those with the C2 subtype. A 3-gene signature consisting of LY6D, BCAT1, and ITGB6 based on 538 DEGs between both subtypes serves as a stable prognostic marker in patients with pancreatic cancer across multiple cohorts. LY6D, BCAT1, and ITGB6 were over-expressed in 120 PAAD samples compared to normal samples.

Conclusions

The constructed 3-gene signature can be used as a molecular marker to assess the prognostic risk in patients with PAAD.

Integrated analysis of miRNA and mRNA transcriptomic reveals antler growth regulatory network

The growth of antler is driven by endochondral ossification in the growth center of the apical region. Antler grows faster than cancer tissues, but it can be stably regulated and regenerated periodically. To elucidate the molecular mechanisms of how antler grows rapidly without carcinogenesis, in this study, we used RNA-seq technology to evaluate the changes of miRNA and mRNA profiles in antler at four different developmental stages, including 15, 60, 90, and 110 days. We identified a total of 55004 unigenes and 246 miRNAs of which, 10182, 13258, 10740 differentially expressed (DE) unigenes and 35, 53, 27 DE miRNAs were identified in 60-day vs. 15-day, 90-day vs. 60-day, and 110-day vs. 90-day. GO and KEGG pathway analysis indicated that DE unigenes and DE miRNA were mainly associated with chondrogenesis, osteogenesis and inhibition of oncogenesis, that were closely related to antler growth. The interaction networks of mRNA-mRNA and miRNA-mRNA related to chondrogenesis, osteogenesis and inhibition of oncogenesis of antler were constructed. The results indicated that mRNAs (COL2A1, SOX9, WWP2, FGFR1, SPARC, LOX, etc.) and miRNAs (miR-145, miR-199a-3p, miR-140, miR-199a-5p, etc.) might have key roles in chondrogenesis and osteogenesis of antler. As well as mRNA (TP53, Tpm3 and ATP1A1, etc.) and miRNA (miR-106a, miR-145, miR-1260b and miR-2898, etc.) might play important roles in inhibiting the carcinogenesis of antler. In summary, we constructed the mRNA-mRNA and miRNA-mRNA regulatory networks related to chondrogenesis, osteogenesis and inhibition of oncogenesis of antler, and identified key candidate mRNAs and miRNAs among them. Further developments and validations may provide a reference for in-depth analysis of the molecular mechanism of antler growth without carcinogenesis.

Dynamic financial economic fluctuation model based on non-normal distribution

This paper discusses the modeling of financial volatility under the condition of non-normal distribution. In order to solve the problem that the traditional central moment cannot estimate the thick-tailed distribution, the L-moment which is widely used in the hydrological field is introduced, and the autoregressive conditional moment model is used for static and dynamic fitting based on the generalized Pareto distribution. In order to solve the dimension disaster of multidimensional conditional skewness and kurtosis modeling, the multidimensional skewness and kurtosis model based on distribution is established, and the high-order moment model is deduced. Finally, the problems existing in the traditional investment portfolio are discussed, and on this basis, the high-order moment portfolio is further studied. The results show that the key lies in the selection of the model and the assumption of asset probability distribution. Financial risk analysis can be effective only with a large sample. High-frequency data contain more information and can provide rich data resources. The conditional generalized extreme value distribution can well describe the time-varying characteristics of scale parameters and shape parameters and capture the conditional heteroscedasticity in the high-frequency extreme value time series. Better describe the persistence and aggregation of the extreme value of high frequency data as well as the peak and thick tail characteristics of its distribution.

The m6A methyltransferase METTL3 aggravates the progression of nasopharyngeal carcinoma through inducing EMT by m6A-modified Snail mRNA

BACKGROUND

This study aims to elucidate the role of METTL3 in aggravating the progression of NPC through m6A modification on Snail and thus the stimulated EMT (epithelial-mesenchymal transition).

PATIENTS AND METHODS

Differential expressions of METTL3 in 48 paired NPC tissues and paracancerous tissues were determined by quantitative real-time polymerase chain reaction (qRT-PCR). Its level in NPC patients with different clinical stages and metastatic states was examined. Prognostic potential of METTL3 in NPC patients was assessed by Kaplan-Meier method. After knockdown of METTL3, expression changes of Snail and EMT-related genes, as well as invasive and migratory abilities in SUNE-1 cells were detected. The interaction between Snail with METTL3 and IGF2BP2 was verified by RIP (RNA-Binding Protein Immunoprecipitation) assay. At last, the roles of METTL3/Snail regulatory loop in influencing EMT and metastasis of NPC were clarified.

RESULTS

METTL3 was upregulated in NPC tissues than that of paracancerous ones. NPC patients with advanced stage or lymphatic metastasis expressed higher level of METTL3. Kaplan-Meier curves revealed that NPC patients expressing high level of METTL3 suffered worse prognosis. Knockdown of METTL3 downregulated protein levels of Snail and N-cadherin, while E-cadherin was upregulated in SUNE-1 cells. Meanwhile, knockdown of METTL3 inhibited invasive and migratory abilities in NPC cells. RIP assay confirmed the interaction between Snail and METTL3. Besides, knockdown of METTL3 decreased the enrichment abundance of Snail in anti-IGF2BP2. Overexpression of Snail partially reversed the regulatory effects of METTL3 on EMT-related gene expressions and metastatic abilities in NPC.

CONCLUSIONS

METTL3 is upregulated in NPC, which regulates EMT and metastasis in NPC cells through m6A-modified Snail mRNA.

DEP Domain-Containing Protein 1B (DEPDC1B) Promotes Migration and Invasion in Pancreatic Cancer Through the Rac1/PAK1-LIMK1-Cofilin1 Signaling Pathway

Background

With increasing incidence, pancreatic cancer (PC) is one of the most common digestive tract tumors. However, the prognosis of PC is particularly dismal due to the highly invasive and metastatic behavior of this deadly disease. DEP domain-containing protein 1B (DEPDC1B), which is overexpressed in multiple tumors, such as breast cancer, oral cancer and non-small cell lung cancer, plays a significant role in cell movement, cell cycle and cytoskeleton reorganization. However, the function of DEPDC1B in PC remains poorly understood.

Methods

The function of DEPDC1B in the migration and invasion of PC was evaluated by wound healing and Transwell assays in vitro and PC-derived liver metastasis models in vivo. The molecular mechanisms of DEPDC1B were investigated through cell line establishment, Western blotting, qRT-PCR, immunoprecipitation, histological examination and immunohistochemistry analysis.

Results

DEPDC1B was overexpressed in PC cell lines. DEPDC1B regulated cell migration and invasion. DEPDC1B regulated the Rac1/PAK1-LIMK1-cofilin1 signaling pathway by interacting with Rac1. Rac1 inhibition suppressed DEPDC1B-induced migration and invasion in PC in vitro and DEPDC1B-induced liver metastasis in vivo.

Conclusion

DEPDC1B promoted cell migration and invasion by activating the Rac1/PAK1-LIMK1-cofilin1 signaling pathway, thus providing a potential therapeutic target against PC.

Long noncoding RNA CERS6-AS1 functions as a malignancy promoter in breast cancer by binding to IGF2BP3 to enhance the stability of CERS6 mRNA

Breast cancer (BC) leads to the highest mortality in women worldwide, characterized by inevitable proliferation and metastasis of BC cells. Mounting evidence confirm that lncRNAs play a significant role in the tumorigenesis and development of BC. lncRNA CERS6-AS1 is a novel discovery, and its role and molecular mechanism in BC has not been studied. In this study, it was discovered that CERS6-AS1 was overexpressed in BC tissues and cells. CERS6-AS1 accelerated cell proliferation and suppressed cell apoptosis in BC. Moreover, molecular mechanism exploration uncovered that there was a positive association between CERS6 and CERS6-AS1 (or IGF2BP3) expression in BC. Furthermore, IGF2BP3 serves as a RNA-binding protein for CERS6-AS1 and CERS6-AS1 promoted CERS6 mRNA stability by binding to IGF2BP3. In the end, rescue experiments verified that overexpression of CERS6 rescues the inhibition of CERS6-AS1 deficiency on BC progression in vitro and vivo. Taken together, these evidences suggested that CERS6-AS1 promoted the progression of BC by binding to IGF2BP3 and thus enhancing the stability of CERS6 mRNA, providing a new underlying therapeutic target for BC to improve prognosis.

Overexpression of SLFN5 induced the epithelial-mesenchymal transition in human lung cancer cell line A549 through β-catenin/Snail/E-cadherin pathway

Lung cancer is a disease with increasing morbidity worldwide in recent years. Approaches such as chemotherapy and biological targeting for its treatment are urgently needed. Epithelial-mesenchymal transition (EMT) is an important initiation stage for tumor cells to acquire invasive and metastatic abilities. Increasing findings have shown that human schlafen family member 5 (SLFN5) plays a key role in malignant tumors. However, the role of SLFN5 in lung cancer cells is not completely elucidated yet. In this study, overexpression or knockdown of SLFN5 gene were induced by lentiviral transfection in human lung cancer cell line A549, then the EMT of A549 was detected by green fluorescent protein labeling method, the migrative and invasive abilities were evaluated via transwell and wound-healing tests in vitro and chick chorioallantoic membrane inoculation in vivo, and the possible mechanism was studied by quantitative real-time PCR and Western blotting. Our results demonstrated that overexpression of SLFN5 promoted the morphology transformation of A549 from epithelial to mesenchymal, as well as migration and invasion. However, knockdown of SLFN5 resulted in the opposite results. Moreover, with the development of EMT after SLFN5 was overexpressed, A549 exhibited enhanced translocation of β-catenin from membrane to cytoplasm or nucleus, with higher level of EMT-related transcription factor Snail, and lower expression of adhesin E-cadherin. Together these results suggest that SLFN5 may act as a synergist in lung cancer cell tumorigenesis and progression, providing a potential target for developing drugs for lung cancer therapy in future.