PP4C facilitates lung cancer proliferation and inhibits apoptosis via activating MAPK/ERK pathway

Comprehensive analysis of PPP4C's impact on prognosis, immune microenvironment, and immunotherapy response in lung adenocarcinoma using single-cell sequencing and multi-omics

Background

Elevated PPP4C expression has been associated with poor prognostic implications for patients suffering from lung adenocarcinoma (LUAD). The extent to which PPP4C affects immune cell infiltration in LUAD, as well as the importance of associated genes in clinical scenarios, still requires thorough investigation.

Methods

In our investigation, we leveraged both single-cell and comprehensive RNA sequencing data, sourced from LUAD patients, in our analysis. This study also integrated datasets of immune-related genes from InnateDB into the framework. Our expansive evaluation employed various analytical techniques; these included pinpointing differentially expressed genes, constructing WGCNA, implementing Cox proportional hazards models. We utilized these methods to investigate the gene expression profiles of PPP4C within the context of LUAD and to clarify its potential prognostic value for patients. Subsequent steps involved validating the observed enhancement of PPP4C expression in LUAD samples through a series of experimental approaches. The array comprised immunohistochemistry staining, Western blotting, quantitative PCR, and a collection of cell-based assays aimed at evaluating the influence of PPP4C on the proliferative and migratory activities of LUAD cells.

Results

In lung cancer, elevated expression levels of PPP4C were observed, correlating with poorer patient prognoses. Validation of increased PPP4C levels in LUAD specimens was achieved using immunohistochemical techniques. Experimental investigations have substantiated the role of PPP4C in facilitating cellular proliferation and migration in LUAD contexts. Furthermore, an association was identified between the expression of PPP4C and the infiltration of immune cells in these tumors. A prognostic framework, incorporating PPP4C and immune-related genes, was developed and recognized as an autonomous predictor of survival in individuals afflicted with LUAD. This prognostic tool has demonstrated considerable efficacy in forecasting patient survival and their response to immunotherapeutic interventions.

Conclusion

The involvement of PPP4C in LUAD is deeply intertwined with the tumor's immune microenvironment. PPP4C's over-expression is associated with negative clinical outcomes, promoting both tumor proliferation and spread. A prognostic framework based on PPP4C levels may effectively predict patient prognoses in LUAD, as well as the efficacy of immunotherapy strategy. This research sheds light on the mechanisms of immune interaction in LUAD and proposes a new strategy for treatment.

Downregulation of HIGD1B induces mitochondria-mediated apoptosis in gastric cancer cells by inactivating Akt and ERK pathways

Gastric cancer (GC) is one of the most common malignancies worldwide. Hypoxia-inducible domain (HIGD) family members (e.g., HIGD1A) have been linked to tumor progression. However, the role of HIGD1B (another HIGD family member) in GC has yet to be fully understood. Based on data from TCGA_GC, GSE65801, and GSE65801 data sets, HIGD1B levels were evaluated in normal and GC tissues. Next, HIGD1B levels were validated by reverse transcription-quantitative PCR and western blot analysis analyses. Meanwhile, patients with GC in the TCGA_GC cohort were grouped into high- and low-HIGD1B level groups, and overall survival, functional enrichment, and immune infiltration were analyzed. Additionally, gain- and loss-of-function experiments were performed to determine the function of HIGD1B in GC cells. Compared to normal controls, HIGD1B mRNA levels were significantly elevated in GC tissues. Moreover, high HIGD1B levels may be an independent indicator of poor prognosis in patients with GC. Additionally, high HIGD1B levels were correlated with high stromal and ESTIMATE scores and elevated expression of immune checkpoints in patients with GC. Functional analyses showed that HIGD1B deficiency notably suppressed GC cell proliferation, migration, and invasion. Moreover, HIGD1B deficiency significantly induced mitochondria-mediated apoptosis in GC cells by inactivating Akt and ERK pathways. Collectively, HIGD1B may predict the prognosis of patients with GC and may function as an oncogene in GC. These findings suggest that HIGD1B may serve as a prognostic biomarker and potential therapeutic target in GC.

Maimendong and Qianjinweijing Tang combined with cisplatin suppressed lung cancer through targeting lncRNA-p21

ETHNOPHARMACOLOGICAL RELEVANCE

Maimendong and Qianjinweijing Tang (Jin formula) is a traditional Chinese medicine formula that has been proven effective in the treatment of lung cancer in long-term clinical practice.

AIM OF THE STUDY

To evaluate the anti-tumor effects of Jin formula combined with cisplatin (JIN + DDP) in vivo and in vitro, as well as to explore the role of long non-coding RNA (lncRNA) in the anti-lung cancer mechanism of its action.

MATERIALS AND METHODS

A Lewis lung cancer model was established in C57 BL/6 mice to study the in vivo anti-tumor effect of Jin formula combined with cisplatin. TUNEL staining and western blot were applied to study the effects of Jin formula combined cisplatin on apoptosis. The in vitro anti-cancer function of Jin formula combined with cisplatin was explored by cell viability assay, flow cytometry, wound healing assay and transwell assay. The changes in lncRNA expression profiles were determined by lncRNA microarray, and the differentially expressed lncRNA-p21 was verified by quantitative reverse-transcription polymerase chain reaction (qRT-PCR) analysis. The expression differences of lncRNA-p21 in tumor and normal tissues were analyzed by bioinformatics, and the expression differences of lncRNA-p21 in tumor cells and normal cells were detected by qRT-PCR. The role of lncRNA-p21 in the anti-cancer effect of Jin formula combined cisplatin was investigated by knockdown or overexpression of lncRNA-p21 and a series of cell experiments. The expression of MAPK pathway-related proteins was analyzed by western blot.

RESULTS

Jin formula combined with cisplatin (JIN + DDP) can suppress tumor growth and promote apoptosis in Lewis lung cancer mouse model. LncRNA-p21 was significantly up-regulated in the JIN and JIN + DDP groups, and the expression of lncRNA-p21 in lung cancer tissues and cells was lower than that in normal tissues and cells. In vitro, JIN + DDP significantly induced apoptosis and inhibited the proliferation, migration, and invasion of H460 and H1650 lung cancer cells. The above effects can be enhanced by the overexpression of lncRNA-p21 and eliminated by knock-down of lncRNA-p21. Further studies revealed that JIN + DDP inhibited the expression of mitogen-activated protein kinase (MAPK) pathway-related proteins, whereas knock-down of lncRNA-p21 abrogated the inhibition of the MAPK signaling pathway.

CONCLUSIONS

This study showed that Jin formula combined with cisplatin could effectively inhibit the progression of lung cancer partially through targeting lncRNA-p21.

Single-cell and transcriptomic analyses reveal the influence of diabetes on ovarian cancer

BACKGROUND

There has been a significant surge in the global prevalence of diabetes mellitus (DM), which increases the susceptibility of individuals to ovarian cancer (OC). However, the relationship between DM and OC remains largely unexplored. The objective of this study is to provide preliminary insights into the shared molecular regulatory mechanisms and potential biomarkers between DM and OC.

METHODS

Multiple datasets from the GEO database were utilized for bioinformatics analysis. Single cell datasets from the GEO database were analysed. Subsequently, immune cell infiltration analysis was performed on mRNA expression data. The intersection of these datasets yielded a set of common genes associated with both OC and DM. Using these overlapping genes and Cytoscape, a protein‒protein interaction (PPI) network was constructed, and 10 core targets were selected. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were then conducted on these core targets. Additionally, advanced bioinformatics analyses were conducted to construct a TF-mRNA-miRNA coregulatory network based on identified core targets. Furthermore, immunohistochemistry staining (IHC) and real-time quantitative PCR (RT-qPCR) were employed for the validation of the expression and biological functions of core proteins, including HSPAA1, HSPA8, SOD1, and transcription factors SREBF2 and GTAT2, in ovarian tumors.

RESULTS

The immune cell infiltration analysis based on mRNA expression data for both DM and OC, as well as analysis using single-cell datasets, reveals significant differences in mononuclear cell levels. By intersecting the single-cell datasets, a total of 119 targets related to mononuclear cells in both OC and DM were identified. PPI network analysis further identified 10 hub genesincludingHSP90AA1, HSPA8, SNRPD2, UBA52, SOD1, RPL13A, RPSA, ITGAM, PPP1CC, and PSMA5, as potential targets of OC and DM. Enrichment analysis indicated that these genes are primarily associated with neutrophil degranulation, GDP-dissociation inhibitor activity, and the IL-17 signaling pathway, suggesting their involvement in the regulation of the tumor microenvironment. Furthermore, the TF-gene and miRNA-gene regulatory networks were validated using NetworkAnalyst. The identified TFs included SREBF2, GATA2, and SRF, while the miRNAs included miR-320a, miR-378a-3p, and miR-26a-5p. Simultaneously, IHC and RT-qPCR reveal differential expression of core targets in ovarian tumors after the onset of diabetes. RT-qPCR further revealed that SREBF2 and GATA2 may influence the expression of core proteins, including HSP90AA1, HSPA8, and SOD1.

CONCLUSION

This study revealed the shared gene interaction network between OC and DM and predicted the TFs and miRNAs associated with core genes in monocytes. Our research findings contribute to identifying potential biological mechanisms underlying the relationship between OC and DM.

PP4R1 accelerates the malignant progression of NSCLC via up-regulating HSPA6 expression and HSPA6-mediated ER stress

Protein phosphatase 4 (PP4) plays an indispensable regulatory part in the development and malignant progression of multifarious tumors. Nevertheless, the function of protein phosphatase 4 regulatory subunit 1 (PP4R1), a vital regulatory subunit of PP4, in tumors especially in lung cancer remains blurred. Therefore, this study aimed to investigate the function and mechanism of PP4R1 in the development of non-small cell lung cancer (NSCLC). We analyzed the clinical correlation of PP4R1 based on the TCGA database by UALCAN (https://ualcan.path.uab.edu/index.html) and found that hyper-expression of PP4R1 mRNA was related to the severe prognosis in NSCLC. The subsequent cellular experiments confirmed that the proliferation, colony growth, migration as well as invasion of H1299 and HCC827 were significantly enhanced after PP4R1 overexpression treatment in vitro. Results from animal experiments pointed out that tumors exhibited stronger growth and lung metastatic capacities due to the overexpression of PP4R1. The bioinformatics analysis, including RNA-seq, showed us that PP4R1 significantly promoted the expression of several HSP70 family member genes, with a particularly marked increase in HSPA6, and the enrichment analyses illustrated that the differentially expressed genes (DEGs) were enriched in those pathways related to protein folding. More importantly, the overexpression of HSPA6 resulted in the same malignant progression of NSCLC as PP4R1 overexpression, and both concomitant with the activation of endoplasmic reticulum (ER) stress. In aggregate, PP4R1 contributed to the malignant progression of NSCLC via up-regulating HSPA6 expression and then activating ER stress.

Identification of protein phosphatase 4 catalytic subunit as a Wnt promoting factor in pan-cancer and Xenopus early embryogenesis

Protein Phosphatase 4 Catalytic Subunit (PPP4C) is an evolutionarily conserved protein involved in multiple biological and pathological events, including embryogenesis, organogenesis, cellular homeostasis, and oncogenesis. However, the detailed mechanisms underlying these processes remain largely unknown. Thus, we investigated the potential correlation between PPP4C and biological processes (BPs) and canonical Wnt signaling using pan-cancer analysis and Xenopus laevis (X. laevis) embryo model. Our results indicate that PPP4C is a potential biomarker for specific cancer types due to its high diagnostic accuracy and significant prognostic correlation. Furthermore, in multiple cancer types, PPP4C-related differentially expressed genes (DEGs) were significantly enriched in pattern specification, morphogenesis, and canonical Wnt activation. Consistently, perturbation of Ppp4c in X. laevis embryos interfered with normal embryogenesis and canonical Wnt responses. Moreover, biochemical analysis of X. laevis embryos demonstrated that both endogenous and exogenous Ppp4c negatively regulated AXIN1 (Wnt inhibitor) abundance. This study provides novel insights into PPP4C roles in pattern specification and Wnt activation. The similarities in BPs and Wnt signaling regulation regarding PPP4C support the intrinsic link between tumorigenesis and early embryogenesis.

Rosavin exerts an antitumor role and inactivates the MAPK/ERK pathway in small-cell lung carcinoma in vitro

This study attempts to explore the function and mechanism of action of rosavin in small-cell lung cancer (SCLC) in vitro. The viability and clone formation of SCLC cells were assessed using cell counting kit-8 and colony formation assays, respectively. Apoptosis and cell cycle were detected using flow cytometry and cell cycle analysis, respectively. Wound healing and transwell assays were performed to evaluate the migration and invasion of SCLC cells. Besides, protein levels of p-ERK, ERK, p-MEK and MEK were determined using Western blot analysis. Rosavin repressed the viability and clone formation of SCLC cells, and promoted apoptosis and G₀/G₁ arrest of SCLC cells. At the same time, rosavin suppressed migration and invasion of SCLC cells. Moreover, protein levels of p-ERK/ERK and p-MEK/MEK were decreased after rosavin addition in SCLC cells. Rosavin impaired malignant behaviors of SCLC cells, which may be associated with inhibition of the MAPK/ERK pathway in vitro.

LEM Domain Containing 1 Acts as a Novel Oncogene and Therapeutic Target for Triple-Negative Breast Cancer

Breast cancer is the most common deadly malignancy in women worldwide. In particular, triple-negative breast cancer (TNBC) exhibits the worst prognosis among four subtypes of breast cancer due to limited treatment options. Exploring novel therapeutic targets holds promise for developing effective treatments for TNBC. Here, we demonstrated for the first time that LEMD1 (LEM domain containing 1) is highly expressed in TNBC and contributes to reduced survival in TNBC patients, through analysis of both bioinformatic databases and collected patient samples. Furthermore, LEMD1 silencing not only inhibited the proliferation and migration of TNBC cells in vitro, but also abolished tumor formation of TNBC cells in vivo. Knockdown of LEMD1 enhanced the sensitivity of TNBC cells to paclitaxel. Mechanistically, LEMD1 promoted the progress of TNBC by activating the ERK signaling pathway. In summary, our study revealed that LEMD1 may act as a novel oncogene in TNBC, and targeting LEMD1 may be exploited as a promising therapeutic approach to enhance the efficacy of chemotherapy against TNBC.

The topoisomerase inhibitor CPT-11 prevents the growth and metastasis of lung cancer cells in nude mice by inhibiting EGFR/MAPK signaling pathway

Objective

The topoisomerase inhibitor CPT-11 has been applied in treatment of multiple cancer types. Here, we probed into the possible mechanism of CPT-11 in affecting growth and metastasis of lung cancer (LC) cells, with involvement of the EGFR/MAPK pathway.

Methods

The target protein of CPT-11 was screened through bioinformatics analysis, and the LC-related microarray datasets GSE29249, GSE32863 and GSE44077 were obtained for differential analysis for identifying the target protein. A subcutaneous xenograft tumor model and a metastatic tumor model were constructed in nude mice for in vivo mechanism verification of the regulatory role of CPT-11 in LC through modulation of EGRF/MAPK pathway.

Results

Bioinformatics analysis showed that EGFR was the target protein of CPT-11. In vivo animal experiments confirmed that CPT-11 enhanced LC cell growth and metastasis in nude mice. CPT-11 could inhibit activation of EGFR/MAPK pathway. EGFR promoted LC cell growth and metastasis in nude mice through activation of the MAPK pathway.

Conclusion

The topoisomerase inhibitor CPT-11 may prevent LC growth and metastasis by inhibiting activation of EGFR/MAPK pathway.

Purinergic P2X7R as a potential target for pancreatic cancer

Pancreatic cancer is one of the deadliest types of cancer, with a death rate nearly equal to the incidence. The P2X7 receptor (P2X7R) is a kind of extracellular adenosine triphosphate (ATP)-gated ion channel with special permeability, which exists in most tissues of human body and mediates inflammation-related signaling pathways and immune signal transduction after activation. P2X7R is also present on the surface of several tumor cells and is involved in tumor growth and progression. P2X7R expression in pancreatic cancer has also been identified in recent studies. Activation of P2X7R in pancreatic cancer can support the proliferation of pancreatic stellate cells, participate in protein interactions, and mediate ERK1/2, IL-6/STAT3, hCAP-18/LL-37, PI3K/AKT signaling pathways to promote pancreatic cancer progression. Inhibitors targeting P2X7R can inhibit the development of pancreatic cancer and are expected to be used in clinical therapy. Therefore, P2X7R is promising as a potential therapeutic target for pancreatic cancer. This article reviews the progress of research on P2X7R in pancreatic cancer.

ThPOK inhibits the immune escape of gastric cancer cells by inducing STPG1 to inactivate the ERK pathway

Background

Gastric cancer is the second most frequently diagnosed cancer worldwide. Weak immunogenicity helps cancer cells escape from immune elimination and grow into predominant subpopulations. This study aimed to investigate the effect of Zinc finger and BTB domain containing 7B (Zbtb7b, Alias ThPOK) on T cell activation after coculture with gastric cancer cells.

Methods

Cell Counting Kit-8 assay (CCK-8) was performed to explore the viability of gastric cancer cells. Flow cytometry analysis was used to measure CD3+ T cell proliferation and the ratio of activated IFN-γ+ T cells which were co-incubated with gastric cancer cells (HGC-27, SNU-1). The binding between ThPOK and the promoter of its target sperm tail PG-rich repeat containing 1 (STPG1) was explored using ChIP and luciferase reporter assays. Relative gene expression was quantified using RT-qPCR.

Results

ThPOK was expressed at a low level in gastric cancer tissues and cells at mRNA and protein levels. Gastric cancer patients with lower ThPOK expression had poorer prognosis. ThPOK overexpression suppressed gastric cancer cell viability and increased T cell activation. ThPOK served as a transcription factor for STPG1. STPG1 expression was also at a low level in the tissues and cells of gastric cancer. ThPOK positively regulated the mRNA and protein levels of STPG1 in gastric cancer cells. Moreover, ThPOK was demonstrated to bind with STPG1 promoter. STPG1 upregulation also exerted inhibitory effects on gastric cancer cell viability and T cell activation. Additionally, ThPOK and STPG1 were revealed to inactivate the ERK pathway in gastric cancer cells.

Conclusion

ThPOK inhibits gastric cancer cell viability and increases T cell activation by inducing STPG1 to inactivate the ERK pathway.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12865-022-00485-5.

Comprehensive analysis of PPPCs family reveals the clinical significance of PPP1CA and PPP4C in breast cancer

The phosphoprotein phosphatase catalytic subunit (PPPCs) family has been shown to play an important role in the development and progression of various malignancies, but its expression patterns and biological functions in breast cancer (BC) remain unclear. Therefore, we aimed to investigate the clinical significance and biological functions of the PPPCs family to understand its possible significance in the diagnosis, prognosis and treatment of breast cancer. We comprehensively investigated the expression levels, diagnostic accuracy, prognostic outcomes, biological functions and effects on immune cell infiltration of the PPPCs family in breast cancer using online databases. Except for PPP1CB, PPP1CC, PPP5C and PPEF1, the mRNA expression levels of the PPPCs family in breast cancer tissues were significantly different from those in paracancerous tissues. The differentially expressed genes (DEGs) were associated with the clinicopathological parameters and prognosis of breast cancer. The DEGs were mainly associated with the WNT signaling pathway, antigen presentation and DNA repair. In addition, the DEGs significantly affected the infiltration of immune cells in breast cancer tissues. Among the PPPCs family, PPP1CA and PPP4C played a prominent role in the progression of breast cancer, and inhibition of PPP1CA and PPP4C expression by siRNA can significantly inhibit breast cancer cells proliferation and migration. In conclusion, the PPPCs family, especially PPP1CA and PPP4C, could be used as new biomarkers to improve diagnostic accuracy, predict prognosis and novel targets for the treatment of breast cancer.

Chemical Characteristics of Platycodon grandiflorum and its Mechanism in Lung Cancer Treatment

Objective: The technology, network pharmacology and molecular docking technology of the ultra performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF-MS/MS) were used to explore the potential molecular mechanism of Platycodon grandiflorum (PG) in the treatment of lung cancer (LC).

Methods: UPLC-Q-TOF-MS/MS technology was used to analyze the ingredients of PG and the potential LC targets were obtained from the Traditional Chinese Medicine Systems Pharmacology database, and the Analysis Platform (TCMSP), GeneCards and other databases. The interaction network of the drug-disease targets was constructed with the additional use of STRING 11.0. The pathway enrichment analysis was carried out using Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) in Metascape, and then the “Drug-Ingredients-Targets-Pathways-Disease” (D-I-T-P-D) network was constructed using Cytoscape v3.7.1. Finally, the Discovery Studio 2016 (DS) software was used to evaluate the molecular docking.

Results: Forty-seven compounds in PG, including triterpenoid saponins, steroidal saponins and flavonoids, were identified and nine main bioactive components including platycodin D were screened. According to the method of data mining, 545 potential drug targets and 2,664 disease-related targets were collected. The results of topological analysis revealed 20 core targets including caspase 3 (CASP3) and prostaglandin-endoperoxide synthase 2 (PTGS2) suggesting that the potential signaling pathway potentially involved in the treatment of LC included MAPK signaling pathway and P13K-AKT signaling pathway. The results of molecular docking proved that the bound of the ingredients with potential key targets was excellent.

Conclusion: The results in this study provided a novel insight in the exploration of the mechanism of action of PG against LC.

Therapeutic effects and mechanisms of actions of Descurainia sophia

Descurainia sophia Webb ex Prantl has been used in traditional medicine globally. It has been shown that Descurainia sophia, together with many other bioactive compounds, can modulate the biological functions of various genes. We have viewed the clinical benefits and mechanisms of action of Descurainia sophia associated with its current uses and outlined potential further applications. There are many studies documenting its numerous clinical effects in cancer, respiratory, gastrointestinal, and cardiac systems. Further, Descurainia sophia has been shown to exhibit anti-inflammatory, anti-oxidative, and anthelmintic activities. The clinical studies did not indicate any significant adverse effects of Descurainia sophia, demonstrating that it is a safe and effective herbal medicine. However, more clinical studies demonstrating the therapeutic effects of Descurainia sophia are still warranted.