LNK promotes the growth and metastasis of triple negative breast cancer via activating JAK/STAT3 and ERK1/2 pathway

Role of STAT3 in cancer cell epithelial‑mesenchymal transition (Review)

Since its discovery, the role of the transcription factor, signal transducer and activator of transcription 3 (STAT3), in both normal physiology and the pathology of numerous diseases, including cancer, has been extensively studied. STAT3 is aberrantly activated in different types of cancer, fulfilling a critical role in cancer progression. The biological process, epithelial‑mesenchymal transition (EMT), is indispensable for embryonic morphogenesis. During the development of cancer, EMT is hijacked to confer motility, tumor cell stemness, drug resistance and adaptation to changes in the microenvironment. The aim of the present review was to outline recent advances in knowledge of the role of STAT3 in EMT, which may contribute to the understanding of the function of STAT3 in EMT in various types of cancer. Delineating the underlying mechanisms associated with the STAT3‑EMT signaling axis may generate novel diagnostic and therapeutic options for cancer treatment.

CircRNA circRREB1 promotes tumorigenesis and progression of breast cancer by activating Erk1/2 signaling through interacting with GNB4

Current investigations have illuminated the essential roles played by circular RNAs (circRNAs) in driving breast cancer (BC) tumorigenesis. However, the functional implications and molecular underpinnings of most circRNAs in BC are not well characterized. Here, Circular RNA (circRNA) expression profiles were analyzed in four surgically resected BC cases along with adjacent non-cancerous tissues applying RNA microarray analysis. The levels and prognostic implications of circRREB1 in BC were subjected to quantitative real-time PCR (qRT-PCR) and in situ hybridization (ISH). Experimental manipulation of circRREB1 levels in both in vivo and in vitro settings further delineated its role in BC cell growth, invasion, and metastasis. The mechanical verification of circRREB1's interaction with GNB4 was established through RNA pull-down, mass spectrometry, Western blot analysis, RNA immunoprecipitation assays (RIP), fluorescence ISH (FISH), and rescue experiments. We found that circRREB1 exhibited significant upregulation in BC tissues and cells, implicating its association with an unfavorable prognosis in BC patients. CircRREB1 knockdown elicited anti-proliferative, anti-migratory, anti-invasive, and pro-apoptotic effects in BC cells, whereas its upregulation exerted opposing influences. Follow-up mechanistic examinations suggested that circRREB1 might interact with GNB4 directly, inducing the activation of Erk1/2 signaling and driving BC progression. Our findings collectively indicate that the interplay of circRREB1 with GNB4 promotes Erk1/2 signaling, thereby fostering BC progression, and positioning circRREB1 as a candidate therapeutic target for intervention in BC.

A novel strategy of integrating network pharmacology and transcriptome reveals antiapoptotic mechanisms of Buyang Huanwu Decoction in treating intracerebral hemorrhage

ETHNOPHARMACOLOGICAL RELEVANCE

Buyang Huanwu Decoction (BYHWD), as a traditional Chinese medical prescription, has been used to treat intracerebral hemorrhage (ICH) for hundreds of years, but the antiapoptotic properties have not yet been studied.

AIM OF THE STUDY

This study aims to elucidate the antiapoptotic mechanism of BYHWD in ICH.

MATERIALS AND METHODS

The therapeutic effect of BYHWD on ICH was assessed by modified neurological severity scores (mNSS), foot fault, and histopathological staining. Then, we used a modified comprehensive strategy by integrating transcriptome and network pharmacology to reveal the underlying mechanism. TUNEL assay, qRT-PCR, and western blot were further applied to evaluate the antiapoptotic effect of BYHWD on ICH. Dual-luciferase reporter assay and plasmid transfections were implemented to validate the potential competing endogenous RNAs (ceRNA) mechanism of Sh2b3.

RESULTS

Network pharmacology analysis indicated that the regulation of the apoptotic process was the highest enriched GO term, and that MAP kinase activity, ERK1, and ERK2 cascade were strongly correlated. Transcriptome analysis screened 180 differentially expressed mRNAs, which were highly enriched in the immune system process and negative regulation of programmed cell death. By checking the literature, we found that Sh2b3 was of great importance to apoptosis by modulating MAPK cascades. TUNEL assay validated the anti-apoptotic effect of BYHWD. Moreover, BYHWD was proven to regulate the Sh2b3-mediated ERK1/2 signaling pathway in ICH mice by qRT-PCR and western blot. We further explored the lncRNA-miRNA-mRNA network underlying the therapeutic effect, among which 4933404O12Rik/miR-185-5p is the upstream regulatory mechanism of Sh2b3.

CONCLUSIONS

We explored the antiapoptotic mechanism of BYHWD in treating ICH by a novel integrated strategy, which involved the 4933404O12Rik/miR-185-5p/Sh2b3 ceRNAs axis.

Modulation of JAK-STAT Signaling by LNK: A Forgotten Oncogenic Pathway in Hormone Receptor-Positive Breast Cancer

Breast cancer remains the most frequently diagnosed cancer in women worldwide. Tumors that express hormone receptors account for 75% of all cases. Understanding alternative signaling cascades is important for finding new therapeutic targets for hormone receptor-positive breast cancer patients. JAK-STAT signaling is commonly activated in hormone receptor-positive breast tumors, inducing inflammation, proliferation, migration, and treatment resistance in cancer cells. In hormone receptor-positive breast cancer, the JAK-STAT cascade is stimulated by hormones and cytokines, such as prolactin and IL-6. In normal cells, JAK-STAT is inhibited by the action of the adaptor protein, LNK. However, the role of LNK in breast tumors is not fully understood. This review compiles published reports on the expression and activation of the JAK-STAT pathway by IL-6 and prolactin and potential inhibition of the cascade by LNK in hormone receptor-positive breast cancer. Additionally, it includes analyses of available datasets to determine the level of expression of LNK and various members of the JAK-STAT family for the purpose of establishing associations between expression and clinical outcomes. Together, experimental evidence and in silico studies provide a better understanding of the potential implications of the JAK-STAT-LNK loop in hormone receptor-positive breast cancer progression.

EPN3 plays oncogenic role in non-small cell lung cancer by activating the JAK1/2-STAT3 pathway

The effect of Epsin 3 (EPN3) on non-small cell lung cancer (NSCLC) has not yet been clearly elucidated. This study identified the exact function of EPN3 on NSCLC progression. EPN3 expression in NSCLC patients were analyzed based on the Cancer Genome Atlas database. Kaplan-Meier analysis was implemented to research the effect of EPN3 on patients' survival. EPN3 expression in clinical tissues of 62 NSCLC cases was monitored by real-time quantitative reverse transcription polymerase chain reaction, immunohistochemistry and Western blot. A549 and H1299 cells were transfected with EPN3 shRNA and treated by RO8191 (20 μM). Proliferation was researched by cell counting kit-8 and 5-ethnyl-2 deoxyuridine assays. Apoptosis was monitored by flow cytometry. Migration and invasion was assessed by Transwell experiment. EPN3 effect on A549 cell in vivo growth was researched using nude mice. RO8191 (200 μg) was intratumoral injected into mice. Immunohistochemistry and Western blot was implemented to monitor protein expression in cells and xenograft tumor tissues. EPN3 was abnormally up-regulated in NSCLC patients and cells, indicating a lower overall survival. Loss of EPN3 weakened proliferation, migration and invasion, induced apoptosis, and repressed epithelial-mesenchymal transition in NSCLC cells. Loss of EPN3 inactivated the JAK1/2-STAT3 pathway in NSCLC cells. RO8191 treatment reversed the inhibition of EPN3 knockdown on the malignant phenotype of NSCLC cells. RO8191 intratumoral injection reversed the suppression of EPN3 silencing on NSCLC cell in vivo growth. EPN3 acted as an oncogene in NSCLC via activating the JAK1/2-STAT3 pathway. EPN3 may be a promising target for NSCLC treatment.

TGF-β1/SH2B3 axis regulates anoikis resistance and EMT of lung cancer cells by modulating JAK2/STAT3 and SHP2/Grb2 signaling pathways

The pathogenesis of lung cancer, the most common cancer, is complex and unclear, leading to limited treatment options and poor prognosis. To provide molecular insights into lung cancer development, we investigated the function and underlying mechanism of SH2B3 in the regulation of lung cancer. We indicated SH2B3 was diminished while TGF-β1 was elevated in lung cancer tissues and cells. Low SH2B3 level was correlated with poor prognosis of lung cancer patients. SH2B3 overexpression suppressed cancer cell anoikis resistance, proliferation, migration, invasion, and EMT, while TGF-β1 promoted those processes via reducing SH2B3. SH2B3 bound to JAK2 and SHP2 to repress JAK2/STAT3 and SHP2/Grb2/PI3K/AKT signaling pathways, respectively, resulting in reduced cancer cell anoikis resistance, proliferation, migration, invasion, and EMT. Overexpression of SH2B3 suppressed lung cancer growth and metastasis in vivo. In conclusion, SH2B3 restrained the development of anoikis resistance and EMT of lung cancer cells via suppressing JAK2/STAT3 and SHP2/Grb2/PI3K/AKT signaling cascades, leading to decreased cancer cell proliferation, migration, and invasion.

SH2B3, Transcribed by STAT1, Promotes Glioblastoma Progression Through Transducing IL-6/gp130 Signaling to Activate STAT3 Signaling

Glioblastoma (GBM) is the most common and aggressive brain tumor in adults. The aberrant activation of STAT3 commonly occurs in GBM and is a key player in GBM tumorigenesis. Yet, the aberrant activation of STAT3 signaling is not fully understood. Here, we report that SH2B adaptor protein 3 (SH2B3) is highly expressed in GBM and preferentially expressed in GBM stem cells (GSCs). Moreover, SH2B3 high expression predicts worse survival of GBM patients. Targeting SH2B3 considerably impairs GBM cell proliferation, migration, and GSCs' self-renewal in vitro as well as xenograft tumors growth in vivo. Additionally, we provide evidence suggesting that STAT1 directly binds to the promoter of SH2B3 and activates SH2B3 expression in the transcriptional level. Functionally, SH2B3 facilitates GBM progression via physically interacting with gp130 and acting as an adaptor protein to transduce IL-6/gp130/STAT3 signaling. Together, our work firstly uncovers that the STAT1/SH2B3/gp130/STAT3 signaling axis plays critical roles in promoting GBM progression and provides insight into new prognosis marker and therapeutic target in GBM.

STAT3 Pathway in Gastric Cancer: Signaling, Therapeutic Targeting and Future Prospects

Molecular signaling pathways play a significant role in the regulation of biological mechanisms, and their abnormal expression can provide the conditions for cancer development. The signal transducer and activator of transcription 3 (STAT3) is a key member of the STAT proteins and its oncogene role in cancer has been shown. STAT3 is able to promote the proliferation and invasion of cancer cells and induces chemoresistance. Different downstream targets of STAT3 have been identified in cancer and it has also been shown that microRNA (miR), long non-coding RNA (lncRNA) and other molecular pathways are able to function as upstream mediators of STAT3 in cancer. In the present review, we focus on the role and regulation of STAT3 in gastric cancer (GC). miRs and lncRNAs are considered as potential upstream mediators of STAT3 and they are able to affect STAT3 expression in exerting their oncogene or onco-suppressor role in GC cells. Anti-tumor compounds suppress the STAT3 signaling pathway to restrict the proliferation and malignant behavior of GC cells. Other molecular pathways, such as sirtuin, stathmin and so on, can act as upstream mediators of STAT3 in GC. Notably, the components of the tumor microenvironment that are capable of targeting STAT3 in GC, such as fibroblasts and macrophages, are discussed in this review. Finally, we demonstrate that STAT3 can target oncogene factors to enhance the proliferation and metastasis of GC cells.