Effect of the modulation of leucine zipper tumor suppressor 2 expression on proliferation of various cancer cells functions as a tumor suppressor

LZTS2 methylation as a potential diagnostic and prognostic marker in LIHC and STAD: Evidence from bioinformatics and in vitro analyses

The rising mortality rate from cancer, driven by the absence of reliable biomarkers, highlights the pressing need for advanced diagnostic and prognostic strategies. This study investigates LZTS2's role as a pan-cancer biomarker, emphasizing its predictive value for immunotherapy and therapeutic targeting. Unlike existing biomarkers such as AFP in hepatocellular carcinoma or HER2 in gastric cancer, which exhibit tissue-specific utility, LZTS2 demonstrates unique cross-cancer applicability, as evidenced by its consistent dysregulation in both liver hepatocellular carcinoma (LIHC) and stomach adenocarcinoma (STAD) alongside emerging associations with other malignancies. Leveraging advanced bioinformatics tools and databases including UALCAN, KM-plotter, and The Cancer Genome Atlas (TCGA), alongside experimental validation in LIHC and STAD cell lines, we analyze LZTS2 expression patterns and their clinical relevance. Notably, LZTS2's dual role-acting as a tumor suppressor in some cancers while promoting oncogenesis in others-distinguishes it from conventional single-function markers, offering novel insights into its regulatory versatility. Our findings reveal that LZTS2 mutations and expression levels are closely associated with cancer progression and patient survival, solidifying its potential as a prognostic biomarker. Notably, LZTS2 expression correlates with various clinicopathological parameters, underscoring its significance in cancer biology. Pathway analysis highlights LZTS2's involvement in critical biological processes, providing actionable insights for therapeutic interventions. Quantitative real-time polymerase chain reaction (qRT-PCR) and quantitative methylation-specific PCR (qMSP) experimental validations confirm these results, further establishing LZTS2's utility as a multi-dimensional biomarker that integrates genetic, epigenetic, and immunological features-a capability rarely observed in existing markers. This comprehensive analysis positions LZTS2 as a pivotal player in cancer progression, opening promising avenues for enhanced clinical management.

Phosphorylation of LZTS2 by PLK1 activates the Wnt pathway

Lung adenocarcinoma (LUAD), responsible for nearly half of lung cancer cases, is one of the most prevalent and lethal malignant tumors globally. There is increasing evidence suggesting that the oncoprotein PLK1 plays a role in the onset and advancement of different types of cancer, including LUAD. Nonetheless, the precise mechanism by which PLK1 promotes tumorigenesis remains unclear. In this study, we demonstrate the upregulation of PLK1 in LUAD samples, which leads to a poor prognosis for LUAD patients. Intriguingly, PLK1 enables to bind to LZTS2 and promote its phosphorylation without affecting LZTS2 degradation. Furthermore, we identify that Ser451 is a key phosphorylation site in LZTS2 protein. LZTS2 exerts an anti-tumor effect by restricting the translocation of the transcription factor β-Catenin into the nucleus, thereby suppressing the Wnt pathway. PLK1 disrupts the interaction between LZTS2 and β-Catenin, resulting in the nuclear accumulation of β-Catenin and the activation of the Wnt pathway. Additionally, we reveal that LZTS2 inhibits the proliferation and migration of LUAD cells, which is rescued by PLK1. Finally, PLK1 inhibitors exhibit a dose-dependent suppression of LUAD cell proliferation and migration. Collectively, this study uncovers the pro-tumorigenic mechanism of PLK1, positioning it as a promising therapeutic target for Wnt-related LUAD.

Long non-coding RNA linc00921 suppresses tumorigenesis and epithelial-to-mesenchymal transition of triple-negative breast cancer via targeting miR-9-5p/LZTS2 axis

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer. Dysregulation of long non-coding RNAs (lncRNAs) plays crucial roles in the initiation and progression of TNBC. In this study, we analyzed public GEO profiles to verify the key lncRNAs in TNBC. Linc00921 was selected for further study. Low expression of linc00921 was observed in 49 of 95 TNBC tissues. Low expression of linc00921 was correlated with poor postoperative disease-free survival (DFS) and overall survival (OS) of TNBC patients. Overexpression of linc00921 with lentivirus suppressed the proliferation, migration and invasion of TNBC cells. A luciferase reporter assay showed that linc00921 could sponge miR-9-5p in TNBC. Moreover, linc00921 and miR-9-5p occupied the same Argonaute-2 (Ago2) protein in TNBC cells. Leucine zipper tumor suppressor 2 (LZTS2) was recognized as a target gene of miR-9-5p, and thereby a linc00921/miR-9-5p/LZTS2 axis was identified in TNBC cells. Overexpression of linc00921 promoted nuclear export of β-catenin, neutralized its function, and subsequently promoted epithelial-to-mesenchymal transition (EMT) in TNBC. A xenograft tumor mouse model showed that the miR-9-5p inhibitor upregulates LZTS2 expression and induce nuclear export of β-catenin in TNBC. Thus, linc00921 upregulates LZTS2 by sponging miR-9-5p to suppress tumorigenesis and EMT of TNBC. Linc00921/miR-9-5p/LZTS2 axis may be a novel biomarker and therapeutic target for TNBC patients.

β-Trcp and CK1δ-mediated degradation of LZTS2 activates PI3K/AKT signaling to drive tumorigenesis and metastasis in hepatocellular carcinoma

Distant metastasis is the leading cause of treatment failure in patients with hepatocellular carcinoma (HCC). However, the underlying mechanisms have not been fully elucidated. Here, we report that Leucine zipper tumor suppressor 2 (LZTS2) is downregulated and correlated with poor prognosis in HCC. Furthermore, we provide evidence that LZTS2 associates with p85 to inhibit the activation of PI3K/AKT signaling and impairs HCC tumorigenesis and metastasis in vitro and in vivo. Moreover, we identify LZTS2 as a bona fide substrate of the E3 ligase β-Trcp and protein kinase CK1δ, which are responsible for the ubiquitination and degradation of LZTS2. Importantly, we show that the β-Trcp and CK1δ-mediated degradation of LZTS2 promotes HCC progression and metastasis by activating PI3K/AKT signaling. Collectively, our study not only illustrates the roles of LZTS2 in regulating HCC tumorigenesis and metastasis but also reveals a novel posttranslational modification of LZTS2 by β-Trcp and CK1δ, indicating that the β-Trcp/CK1δ/LZTS2/PI3K axis may be a novel oncogenic driver involved in HCC progression and metastasis.

LZTS2 inhibits PI3K/AKT activation and radioresistance in nasopharyngeal carcinoma by interacting with p85

Phosphoinositide 3-kinase (PI3K) activity is aberrantly activated in nasopharyngeal carcinoma. However, the underlying mechanisms remain unclear. Here, we found that Leucine zipper tumor suppressor 2 (LZTS2) was downregulated and predicted poor prognosis in nasopharyngeal carcinoma patients. Furthermore, we identified the PI3K subunit p85 as a novel LZTS2-interacting protein using an unbiased proteomics approach. Moreover, we demonstrated that LZTS2 competes with p110 for p85 binding and inhibits activation of the PI3K/AKT signaling pathway. Functionally, we showed that LZTS2 suppresses tumorigenesis and radioresistance in nasopharyngeal carcinoma in a p85-dependent manner. Taken together, our results not only provide understanding of the molecular mechanisms by which PI3K/AKT signaling is activated but also suggest that targeting the LZTS2/PI3K/AKT signaling axis is a promising therapeutic strategy for radiosensitization of nasopharyngeal carcinoma.

HTLV-1 Rex: the courier of viral messages making use of the host vehicle

The human T-cell leukemia virus type 1 (HTLV-1) is a retrovirus causing an aggressive T-cell malignancy, adult T-cell leukemia (ATL). Although HTLV-1 has a compact RNA genome, it has evolved elaborate mechanisms to maximize its coding potential. The structural proteins Gag, Pro, and Pol are encoded in the unspliced form of viral mRNA, whereas the Env protein is encoded in singly spliced viral mRNA. Regulatory and accessory proteins, such as Tax, Rex, p30II, p12, and p13, are translated only from fully spliced mRNA. For effective viral replication, translation from all forms of HTLV-1 transcripts has to be achieved in concert, although unspliced mRNA are extremely unstable in mammalian cells. It has been well recognized that HTLV-1 Rex enhances the stability of unspliced and singly spliced HTLV-1 mRNA by promoting nuclear export and thereby removing them from the splicing site. Rex specifically binds to the highly structured Rex responsive element (RxRE) located at the 3' end of all HTLV-1 mRNA. Rex then binds to the cellular nuclear exporter, CRM1, via its nuclear export signal domain and the Rex-viral transcript complex is selectively exported from the nucleus to the cytoplasm for effective translation of the viral proteins. Yet, the mechanisms by which Rex inhibits the cellular splicing machinery and utilizes the cellular pathways beneficial to viral survival in the host cell have not been fully explored. Furthermore, physiological impacts of Rex against homeostasis of the host cell via interactions with numerous cellular proteins have been largely left uninvestigated. In this review, we focus on the biological importance of HTLV-1 Rex in the HTLV-1 life cycle by following the historical path in the literature concerning this viral post-transcriptional regulator from its discovery to this day. In addition, for future studies, we discuss recently discovered aspects of HTLV-1 Rex as a post-transcriptional regulator and its use in host cellular pathways.

NFκB signaling regulates embryonic and adult neurogenesis

Both embryonic and adult neurogenesis involves the self-renewal/proliferation, survival, migration and lineage differentiation of neural stem/progenitor cells. Such dynamic process is tightly regulated by intrinsic and extrinsic factors and complex signaling pathways. Misregulated neurogenesis contributes much to a large range of neurodevelopmental defects and neurodegenerative diseases. The signaling of NFκB regulates many genes important in inflammation, immunity, cell survival and neural plasticity. During neurogenesis, NFκB signaling mediates the effect of numerous niche factors such as cytokines, chemokines, growth factors, extracellular matrix molecules, but also crosstalks with other signaling pathways such as Notch, Shh, Wnt/β-catenin. This review summarizes current progress on the NFκB signaling in all aspects of neurogenesis, focusing on the novel role of NFκB signaling in initiating early neural differentiation of neural stem cells and embryonic stem cells.

rs4919510 in hsa-mir-608 is associated with outcome but not risk of colorectal cancer

BACKGROUND

Colorectal cancer is the third most incident cancer and cause of cancer-related death in the United States. MicroRNAs, a class of small non-coding RNAs, have been implicated in the pathogenesis and prognosis of colorectal cancer, although few studies have examined the relationship between germline mutation in the microRNAs with risk and prognosis. We therefore investigated the association between a SNP in hsa-mir-608, which lies within the 10q24 locus, and colorectal cancer.

METHODS AND RESULTS

A cohort consisting of 245 cases and 446 controls was genotyped for rs4919510. The frequency of the GG genotype was significantly higher in African Americans (15%) compared to Caucasians (3%) controls. There was no significant association between rs4919510 and colorectal cancer risk (African American: OR(GG vs. CC) 0.89 [95% CI, 0.41-1.80]) (Caucasian: OR(GG vs. CC) 1.76, ([95% CI, 0.48-6.39]). However, we did observe an association with survival. The GG genotype was associated with an increased risk of death in Caucasians (HR(GG vs. CC) 3.54 ([95% CI, 1.38-9.12]) and with a reduced risk of death in African Americans (HR(GG vs. CC) 0.36 ([95% CI 0.12-1.07).

CONCLUSIONS

These results suggest that rs4910510 may be associated with colorectal cancer survival in a manner that is dependent on race.

Metabolomic profiling of serum from human pancreatic cancer patients using 1H NMR spectroscopy and principal component analysis

Pancreatic cancer is a malignant tumor with the worst prognosis among all cancers. At the time of diagnosis, surgical cure is no longer a feasible option for most patients, thus early detection of pancreatic cancer is crucial for its treatment. Metabolomics is a powerful new analytical approach to detect the metabolome of cells, tissue, or biofluids. Here, we report the application of (1)H nuclear magnetic resonance (NMR) combined with principal components analysis to discriminate pancreatic cancer patients from healthy controls based on metabolomic profiling of the serum. The metabolic analysis revealed significant lower of 3-hydroxybutyrate, 3-hydroxyisovalerate, lactate, and trimethylamine-N-oxide as well as significant higher level of isoleucine, triglyceride, leucine, and creatinine in the serum from pancreatic cancer patients compared to that of healthy controls. Our data demonstrate that the subtle differences in metabolite profiles in serum of pancreatic cancer patients and that of healthy subjects as a result of physiological and pathological variations could be identified by NMR-based metabolomics and exploited as metabolic markers for the early detection of pancreatic cancer.