Down-regulation of CHERP inhibits neuroblastoma cell proliferation and induces apoptosis through ER stress induction

Pan-Cancer Analysis of the Prognostic and Immunological Role of SEMA7A

Background

Semaphorin7A (SEMA7A) has been found to regulate both nerve and vessel homeostasis, but its specific role in pan-cancer remains uncertain. This research seeks to delve into the function and clinical relevance of SEMA7A in pan-cancer.

Methods

Through an analysis of gene expression omnibus and the cancer genome atlas datasets, we investigated the impact of SEMA7A on prognosis and immune regulation across 33 types of tumors. Variations in SEMA7A expression were observed between cancerous and adjacent normal tissues, with a notable correlation between SEMA7A levels and patient prognosis.

Results

Across most cancer types, SEMA7A expression was linked to the infiltration of immune cells, as well as immune checkpoints and other immune regulators. The findings were further confirmed through quantitative real-time polymerase chain reaction analysis of SEMA7A expression in breast cancer. Further, SEMA7A is positively associated with prognosis in different cancers. Additionally, SEMA7A expression was associated with TMB and MSI in some cancer types, while in 15 types of cancer, there was a correlation between SEMA7A expression and DNA methylation. SEMA7A was associated with the expression of multiple immune checkpoint genes and abundance of tumor-infiltrating immune cells across multiple types of cancer.

Conclusion

This inaugural pan-cancer examination of SEMA7A sheds light on its prognostic and immunological significance in diverse tumor types, suggesting its potential utility as a biomarker for predicting unfavorable outcomes and immune cell infiltration in cancer.

Kuwanon H Inhibits Melanoma Growth through Cytotoxic Endoplasmic Reticulum Stress and Impaired Autophagy Flux

Although great progress has been made recently in targeted and immune-based therapies, additional treatments are needed for most melanoma patients due to acquired chemoresistance, recurrence, or metastasis. Elevated autophagy is required for the pathogenesis of melanoma to attenuate metabolic stress, protecting cancer cells from chemotherapeutics or radiation. Thus, intervention with autophagy is a promising strategy for melanoma treatment. Here, we examined a novel antimelanoma natural compound named kuwanon H (KuH), which significantly inhibited melanoma cell growth in vitro/vivo. Mechanistically, KuH induced cytotoxic endoplasmic reticulum (ER) stress, which inhibited cell viability and induced apoptosis. Meanwhile, KuH-induced ER stress mediated autophagysome formation through the ATF4-DDIT3-TRIB3-AKT-MTOR axis. Importantly, KuH impaired autophagy flux, which contributed to the anticancer effects of KuH. Finally, our results showed that KuH enhanced the sensitivity of melanoma cells to cisplatin, both in vitro and in vivo, by impairing autophagy degradation of reactive oxygen species and damaged mitochondria. Our findings indicate that KuH is a promising candidate anticancer natural product for melanoma therapy.

Cortex Mori extracts induce apoptosis and inhibit tumor invasion via blockage of the PI3K/AKT signaling in melanoma cells

Melanoma, the most aggressive and deadliest form of skin cancer, has attracted increased attention due to its increasing incidence worldwide. The Cortex Mori (CM) has long been used as a classical traditional Chinese medicine (TCM) to treat various diseases, including cancer. The bioactive components and underlying mechanisms, however, remain largely unknown. The current study aims to investigate the anti-melanoma effects of CM and potential mechanisms through combined network pharmacology and bioinformatic analyses, and validated by in vitro and in vivo experiments. We report here that CM has anti-melanoma activity both in vitro and in vivo. Furthermore, 25 bioactive compounds in CM were found to share 142 melanoma targets, and network pharmacology and enrichment analyses suggested that CM inhibits melanoma through multiple biological processes and signaling pathways, particularly the PI3K-AKT signaling inhibition and activation of apoptotic pathways, which were further confirmed by biochemical and histological examinations. Finally, partial CM-derived bioactive compounds were found to show anti-melanoma effects, validating the anti-melanoma potential of bioactive ingredients of CM. Taken together, these results reveal bioactive components and mechanisms of CM in inhibiting melanoma, providing them as potential anti-cancer natural products for the treatment of melanoma.

Comprehensive analyses of PDHA1 that serves as a predictive biomarker for immunotherapy response in cancer

Recent studies have proposed that pyruvate dehydrogenase E1 component subunit alpha (PDHA1), a cuproptosis-key gene, is crucial to the glucose metabolism reprogram of tumor cells. However, the functional roles and regulated mechanisms of PDHA1 in multiple cancers are largely unknown. The Cancer Genome Atlas (TCGA), GEPIA2, and cBioPortal databases were utilized to elucidate the function of PDHA1 in 33 tumor types. We found that PDHA1 was aberrantly expressed in most cancer types. Lung adenocarcinoma (LUAD) patients with high PDHA1 levels were significantly correlated with poor prognosis of overall survival (OS) and first progression (FP). Kidney renal clear cell carcinoma (KIRC) patients with low PDHA1 levels displayed poor OS and disease-free survival (DFS). However, for stomach adenocarcinoma (STAD), the downregulated PDHA1 expression predicted a good prognosis in patients. Moreover, we evaluated the mutation diversity of PDHA1 in cancers and their association with prognosis. We also analyzed the protein phosphorylation and DNA methylation of PDHA1 in various tumors. The PDHA1 expression was negatively correlated with tumor-infiltrating immune cells, such as myeloid dendritic cells (DCs), B cells, and T cells in pan-cancers. Mechanically, we used single-cell sequencing to discover that the PDHA1 expression had a close link with several cancer-associated signaling pathways, such as DNA damage, cell invasion, and angiogenesis. At last, we conducted a co-expressed enrichment analysis and showed that aberrantly expressed PDHA1 participated in the regulation of mitochondrial signaling pathways, including oxidative phosphorylation, cellular respiration, and electron transfer activity. In summary, PDHA1 could be a prognostic and immune-associated biomarker in multiple cancers.

Nup54-induced CARM1 nuclear importation promotes gastric cancer cell proliferation and tumorigenesis through transcriptional activation and methylation of Notch2

Gastric cancer (GC) has the fifth highest incidence globally, but its molecular mechanisms are not well understood. Here, we report that coactivator-associated arginine methyltransferase 1 (CARM1) is specifically highly expressed in gastric cancer and that its overexpression correlates with poor prognosis in patients with gastric cancer. Nucleoporin 54 (Nup54) was identified as a CARM1-interacting protein that promoted CARM1 nuclear importation. In the nucleus, CARM1 cooperates with transcriptional factor EB (TFEB) to activate Notch2 transcription by inducing H3R17me2 of the Notch2 promoter but not H3R26me2. Additionally, the Notch2 intracellular domain (N2ICD) was identified as a CARM1 substrate. Methylation of N2ICD at R1786, R1838, and R2047 by CARM1 enhanced the binding between N2ICD and mastermind-like protein 1 (MAML1) and increased gastric cancer cell proliferation in vitro and tumor formation in vivo. Our findings reveal a molecular mechanism linking CARM1-mediated transcriptional activation of the Notch2 signaling pathway to Notch2 methylation in gastric cancer progression.

Alternative splicing regulation of cell-cycle genes by SPF45/SR140/CHERP complex controls cell proliferation

The regulation of pre-mRNA processing has important consequences for cell division and the control of cancer cell proliferation, but the underlying molecular mechanisms remain poorly understood. We report that three splicing factors, SPF45, SR140, and CHERP, form a tight physical and functionally coherent complex that regulates a variety of alternative splicing events, frequently by repressing short exons flanked by suboptimal 3' splice sites. These comprise alternative exons embedded in genes with important functions in cell-cycle progression, including the G2/M key regulator FOXM1 and the spindle regulator SPDL1. Knockdown of either of the three factors leads to G2/M arrest and to enhanced apoptosis in HeLa cells. Promoting the changes in FOXM1 or SPDL1 splicing induced by SPF45/SR140/CHERP knockdown partially recapitulates the effects on cell growth, arguing that the complex orchestrates a program of alternative splicing necessary for efficient cell proliferation.

U2-related proteins CHERP and SR140 contribute to colorectal tumorigenesis via alternative splicing regulation

Dysregulation of calcium homeostasis endoplasmic reticulum protein (CHERP) has been implicated in several cancers, but it remains elusive how CHERP contributes to cancer cell proliferation and cancer development. Here, we observed that CHERP and its binding partner SR140 are significantly upregulated in human clinical colorectal cancer tissues (CRC). CHERP and SR140 could form a protein complex to stabilize each other. Knockdown of CHERP or SR140 triggers double-stranded DNA breaks and cell death. Furthermore, UPF3A, the RNA surveillance factor, was identified as a splicing target of CHERP and SR140, which bind specifically to the regulated exon4 and modulate UPF3A splicing. UPF3A knockdown recapitulates CHERP/SR140 depletion both in vitro and in mice. Importantly, overexpression of UPF3A significantly rescues proliferation defect of CHERP/SR140-depleted cells. These results confirmed that the effect of CHERP/SR140 in promoting tumorigenesis was partially mediated by UPF3A. Extending these results, upregulation of CHERP/SR140 observed in CRC remarkably parallels increased inclusion of UPF3A exon4. Together, our study clarifies how CHERP/SR140 exert an oncogenic role in CRC development partially through regulating expression of UPF3A variants.

TP53BP2 decreases cell proliferation and induces autophagy in neuroblastoma cell lines

Tumor protein p53-binding protein 2 (TP53BP2), a member of the apoptosis-stimulating protein of p53 (ASPP) family, has previously been reported to be associated with tumor development. However, to the best of our knowledge, the role of TP53BP2 in neuroblastoma has not been elucidated. The aim of the present study was to investigate the function of TP53BP2 in the proliferation and autophagy of neuroblastoma. An expression vector that expresses TP53BP2-specific short hairpin RNA (shTP53BP2) was used for the experimental group and green fluorescent protein short hairpin RNA was used as a control. Cell proliferation was measured using MTT assays, self-renewal was evaluated using soft agar assays, light chain 3 (LC3) II expression level was examined by western blot and immunofluorescence analysis, and the autophagy-related 3 homolog (ATG3), autophagy-related 5 homolog (ATG5) and autophagy-related 9 homolog (ATG7) expression levels were examined using the reverse transcription-quantitative polymerase chain reaction (RT-qPCR). A genomics analysis revealed that TP53BP2 expression was associated with the survival of patients with neuroblastoma. Western blot and RT-qPCR assays indicated that TP53BP2 could be implicated in neuroblastoma, as the proliferative ability of the experimental group decreased compared with that of the control group (P<0.001) and the expression levels of genes associated with autophagy, including LC3 II. ATG3, ATG5 and ATG7, increased in the experimental group. In conclusion, an increased expression of TP53BP2 in patients with neuroblastoma may be associated with poor survival and shTP53BP2 may decrease the proliferative abilities of neuroblastoma cells, including BE(2)C and SK-N-DZ cell lines. In addition, the LC3 II, ATG3, ATG5 and ATG7 expression levels increased and were associated with increased rates of autophagy following upregulation of TP53BP2.

Cancer cell targeting and therapeutic delivery of silver nanoparticles by mesoporous silica nanocarriers: insights into the action mechanisms using quantitative proteomics

An approach for safely delivering AgNPs to cancer cells and the evaluation of the affected cellular mechanism are presented. The use of mesoporous silica nanoparticles (MSNs) as nanovehicles decorated with transferrin (Tf, targeting agent) provides a nanoplatform for the nucleation and immobilization of AgNPs (MSNs-Tf-AgNPs). We performed the physico-chemical characterization of the nanosystems and evaluated their therapeutic potential using bioanalytical strategies to estimate the efficiency of the targeting, the degree of cellular internalization in two cell lines with different TfR expression, and the cytotoxic effects of the delivered AgNPs. In addition, cellular localization of the nanosystems in cells has been evaluated by a transmission electron microscopy analysis of ultrathin sections of human hepatocarcinoma (HepG2) cells exposed to MSNs-Tf-AgNPs. The in vitro assays demonstrate that only the nanosystem functionalized with Tf is able to transport the AgNPs inside the cells which overexpress transferrin receptors. Therefore, this novel nanosystem is able to deliver AgNPs specifically to cancer cells overexpressing Tf receptors and offers the possibility of a targeted therapy using reduced doses of silver nanoparticles as cytotoxic agents. Then, a quantitative proteomic experiment validated through the analysis of gene expression has been performed to identify the molecular mechanisms of action associated with the chemotherapeutic potential of the MSNs-Tf-AgNP nanocarriers.

Resveratrol induces apoptosis in human melanoma cell through negatively regulating Erk/PKM2/Bcl-2 axis

Background

Resveratrol is known as a natural phytoalexin found in grapes and wine, which has significant antitumor activity under in vitro and in vivo conditions. In recent years, great progress has been made in understanding the underlying mechanisms of resveratrol in inducing cellular apoptosis of melanoma cells. Our previous study has shown that the apoptosis regulation of resveratrol in melanoma cells was independent of activation of classical apoptosis-related protein p53.

Materials and methods

MTT assay and 5-bromo-2′-deoxyuridine staining assay were used to analyze cell viability and proliferation. Immunofluorescence analysis of γ-H2AX was employed to clarify DNA damages. Annexin V–propidine iodide/fluorescein isothiocyanate assay was performed to evaluate the cell apoptosis. The mechanisms underlying the activation of M2-type pyruvate kinase (PKM2) by Erk1/2 to stabilize and maintain Bcl-2 signaling was investigated by subcellular fractionation analyses, immunofluorescence analysis, co-immunoprecipitation assay, ubiquitination assay, and glutathione S-transferase pull-down assay.

Results

In the present study, we found that resveratrol dramatically inhibited melanoma cell proliferation and induced cell apoptosis through upregulation of p53 in a concentration-dependent manner. Conversely, p53 downregulation by short hairpin RNA couldn’t rescue resveratrol-induced cell proliferation inhibition or apoptosis enlargement. Additionally, we found that resveratrol downregulated antiapoptotic protein Bcl-2 and activated Bax in the protein levels by promoting Bcl-2 degradation and cytochrome c release. Moreover, we discovered that PKM2, had a key role in cell apoptosis triggered by resveratrol through interacting with Bcl-2. Based on these results, we overexpressed PKM2 in melanoma cells and found that this prevented resveratrol-induced apoptosis by stabilizing the protein level of Bcl-2.

Conclusion

Taken together, our results provided a novel mechanism accounting for the apoptosis induction of resveratrol in melanoma cells and suggested that downregulating Erk/PKM2/Bcl-2 axis appears to be a new approach for the prevention or treatment of melanoma.