SPP1 promotes radiation resistance through JAK2/STAT3 pathway in esophageal carcinoma

SPP1 promotes tumor progression in esophageal carcinoma by activating focal adhesion pathway

Background

Recurrence and metastasis are the major obstacles affecting the therapeutic efficacy and clinical outcomes for patients with esophageal carcinoma (ESCA). Secreted phosphoprotein 1 (SPP1) is considered as a hub gene in ESCA and is negatively associated with disease-free survival (DFS) in ESCA. However, the exact roles and underlying mechanisms remain elusive. This study aims to examine the roles of SPP1 on ESCA, and elucidate the potential mechanisms.

Methods

Bioinformatics were used to analyze the expression of SPP1 in ESCA tissues, and its relations with clinicopathological characteristics and clinical prognosis in patients with ESCA based on The Cancer Genome Atlas (TCGA) dataset. Loss-of-function was conducted to examine the roles of SPP1 on malignant behaviors of ESCA cells by cell counting kit-8 (CCK8), plate clone, wound healing, and transwell assays. Gene set enrichment analysis (GSEA) was conducted to screen the pathways associated with SPP1 in ESCA. Then, the enriched pathway and the underlying mechanism were elucidated by western blotting, cell adhesion, and cell spreading assays. Lastly, Y15 [a specific inhibitor of focal adhesion kinase (FAK)] was used to examine its potential to inhibit tumor growth in ESCA cells.

Results

SPP1 was upregulated in ESCA tissues compared to the adjacent nontumorous tissues, which was closely associated with clinical stage, lymph node metastasis, histological subtype, and p53 mutation. A high expression of SPP1 indicated a poor clinical prognosis in patients with ESCA. The knockdown of SPP1 inhibited cell proliferative, migratory, and invasive capacities in ESCA cells. GSEA indicated that the focal adhesion pathway was closely related with SPP1 in ESCA. Further studies confirmed that the knockdown of SPP1 suppressed cell adhesion ability and reduced the expression of p-FAK and p-Erk in ESCA cells. In addition, Y15 inhibited FAK autophosphorylation and dramatically inhibited cell proliferation, migration, and invasion in ESCA cells.

Conclusions

SPP1 promotes tumor progression in ESCA by activating FAK/Erk pathway, and FAK is a potential therapeutic target to overcome tumor recurrence and metastasis of ESCA.

Targeting leucine-rich PPR motif-containing protein/LRPPRC by 5,7,4'-trimethoxyflavone suppresses esophageal squamous cell carcinoma progression

JAK2/STAT3/MYC axis is dysregulated in nearly 70 % of human cancers, but targeting this pathway therapeutically remains a big challenge in cancer therapy. In this study, genes associated with JAK2, STAT3, and MYC were analyzed, and potential target genes were selected. Leucine-rich PPR motif-containing protein (LRPPRC) whose function and regulation are not fully understood, emerged as one of top 3 genes in terms of RNA epigenetic modification. Here, we demonstrate LRPPRC may be an independent prognostic indicator besides JAK2, STAT3, and MYC. Mechanistically, LRPPRC impairs N6-methyladenosine (m6A) modification of JAK2, STAT3, and MYC to facilitate nuclear mRNA export and expression. Meanwhile, excess LRPPRC act as a scaffold protein binding to JAK2 and STAT3 to enhance stability of JAK2-STAT3 complex, thereby facilitating JAK2/STAT3/MYC axis activation to promote esophageal squamous cell carcinoma (ESCC) progression. Furthermore, 5,7,4'-trimethoxyflavone was verified to bind to LRPPRC, STAT3, and CDK1, dissociating LRPPRC-JAK2-STAT3 and JAK2-STAT3-CDK1 interaction, leading to impaired tumorigenesis in 4-Nitroquinoline N-oxide induced ESCC mouse models and suppressed tumor growth in ESCC patient derived xenograft mouse models. In summary, this study suggests regulation of m6A modification by LRPPRC, and identifies a novel triplex target compound, suggesting that targeting LRPPRC-mediated JAK2/STAT3/MYC axis may overcome JAK2/STAT3/MYC dependent tumor therapeutic dilemma.

Taraxasterol enhanced bladder cancer cells radiosensitivity via inhibiting the COX-2/PGE2/JAK2/STAT3/MMP pathway

PURPOSE

Radiotherapy with bladder preservation is highly acceptable among patients bearing bladder cancer (BCa), but the occurrence of secondary tolerance (ARR) during treatment is one of the important reasons for the failure of clinical radiotherapy. COX-2 has been frequently reported to be highly expressed and associated with radio-resistance in various cancers. In this study, the feasibility of Taraxasterol (Tara) as a radiosensitizer was investigated, and the target effect of Tara on COX-2 and its underlying mechanism were explored.

METHODS AND MATERIALS

The toxicity of Tara toward BCa cells was detected with the MTT method and cells in response to IR or Tara + IR were compared by clone formation assay. Next, a small RNA interference system (siRNA) was employed to decrease endogenous COX-2 expression in BCa cells, and the stem cell-like features and motion abilities of BCa cells under different treatments were investigated using microsphere formation and transwell chamber assay, respectively. Meanwhile, the expression of a series of inflammation-related molecules and stem cell characteristic molecules was determined by qRT-PCR, western blot and ELISA method. In vivo studies, BCa cells were subcutaneously injected into the right flank of each male mouse. Those mice were then grouped and exposed to different treatment: Tara, IR, IR + Tara and untreated control. The volumes of each tumor were measured every two days and target proteins were detected with immunohistochemical (IHC) staining.

RESULTS

The results show that COX-2 decline, due to COX-2 knocking-down or Tara treatment, could greatly enhance BCa cells' radiosensitivity and significantly decrease their migration, invasion and microsphere formation abilities, companied with the reduce of JAK2, phos-STAT3, MMP2 and MMP9 expression. However, Tara could not further reduce the expression of an above molecule of cells in COX-2-deficient BCa cells. Correspondingly, Tara treatment could not further enhance those siCOX-2 BCa cells response to IR.

CONCLUSIONS

Our data support that Tara can improve the radiosensitivity of BCa cells by targeting COX-2/PGE2. The mechanism may involve regulating STAT3 phosphorylation, DNA damage response protein activation, and expression of MMP2/MMP9.

Targeting the cGAS-STING Pathway Inhibits Peripheral T-cell Lymphoma Progression and Enhances the Chemotherapeutic Efficacy

Peripheral T-cell lymphoma (PTCL) is a highly heterogeneous group of mature T-cell malignancies. The efficacy of current first-line treatment is dismal, and novel agents are urgently needed to improve patient outcomes. A close association between the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway and tumor promotion exists, revealing prospective therapeutic targets. This study, investigates the role of the cGAS-STING pathway and its underlying mechanisms in PTCL progression. Single-cell RNA sequencing showes that the cGAS-STING pathway is highly expressed and closely associated with PTCL proliferation. cGAS inhibition suppresses tumor growth and impaires DNA damage repair. Moreover, Cdc2-like kinase 1 (CLK1) is critical for residual tumor cell survival after treatment with cGAS inhibitors, and CLK1 suppression enhances sensitivity to cGAS inhibitors. Single-cell dynamic transcriptomic analysis indicates reduced proliferation-associated nascent RNAs as the underlying mechanism. In first-line therapy, chemotherapy-triggered DNA damage activates the cGAS-STING pathway, and cGAS inhibitors can synergize with chemotherapeutic agents to kill tumors. The cGAS-STING pathway is oncogenic in PTCL, whereas targeting cGAS suppresses tumor growth, and CLK1 may be a sensitivity indicator for cGAS inhibitors. These findings provide a theoretical foundation for optimizing therapeutic strategies for PTCL, especially in patients with relapsed/refractory disease.

The oncogenic mechanisms of the Janus kinase-signal transducer and activator of transcription pathway in digestive tract tumors

Digestive tract tumors are heterogeneous and involve the dysregulation of multiple signaling pathways. The Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway plays a notable role in the oncogenesis of digestive tract tumors. Typically activated by pro-inflammatory cytokines, it regulates important biological processes, such as cell growth, differentiation, apoptosis, immune responses, and inflammation. The aberrant activation of this pathway manifests in different forms, including mutations in JAKs, overexpression of cytokine receptors, and sustained STAT activation, and contributes to promoting the malignant characteristics of cancer cells, including uncontrolled proliferation, resistance to apoptosis, enhanced invasion and metastasis, angiogenesis, acquisition of stem-like properties, and drug resistance. Numerous studies have shown that aberrant activation of the JAK-STAT pathway is closely related to the development and progression of digestive tract tumors, contributing to tumor survival, angiogenesis, changes in the tumor microenvironment, and even immune escape processes. In addition, this signaling pathway also affects the sensitivity of digestive tract tumors to chemotherapy and targeted therapy. Therefore, it is crucial to comprehensively understand the oncogenic mechanisms underlying the JAK-STAT pathway in order to develop effective therapeutic strategies against digestive tract tumors. Currently, several JAK-STAT inhibitors are undergoing clinical and preclinical trials as potential treatments for various human diseases. However, further investigation is required to determine the role of this pathway, as well as the effectiveness and safety of its inhibitors, especially in the context of digestive tract tumors. In this review, we provide an overview of the structure, classic activation, and negative regulation of the JAK-STAT pathway. Furthermore, we discuss the pathogenic mechanisms of JAK-STAT signaling in different digestive tract tumors, with the aim of identifying potential novel therapeutic targets. Video Abstract.

Role of SPP1 in the diagnosis of gastrointestinal cancer

Recently, the incidence rate of digestive system tumors has increased in China and these tumors occur in a younger population. The present study aimed to determine the expression levels and potential clinical value of secreted phosphoprotein 1 (SPP1) in gastrointestinal cancer. The microarray datasets GSE104836, GSE189830 and GSE103236, obtained from the gene expression omnibus database, were analyzed to determine differentially expressed genes in patients with colorectal cancer (CRC), gastric cancer (GC) and esophageal cancer (EC). A total of 42 patients with CRC, GC or EC and 21 healthy controls were recruited to obtain blood and tissues samples. SPP1 expression levels were detected using reverse transcription-quantitative PCR. Moreover, levels of significance of SPP1 in patients with CRC, GC and EC were analyzed using receiver operating characteristic analysis. Potential correlations between SPP1 and carcinoembryonic antigen (CEA) were assessed using Pearson's correlation coefficient. SPP1 was significantly upregulated in the serum, plasma and tissue of patients with CRC, GC or EC. In addition, the area under the curve of SPP1 was >0.5 in the plasma, serum and cancer tissue of patients with early and late CRC, GC or EC. The present study further demonstrated that the specificity and sensitivity of SPP1 was higher in patients with late CRC, GC or EC compared with patients with early CRC, GC or EC. Moreover, SPP1 and CEA were significantly positively correlated in serum of patients with CRC, GC or EC. In conclusion, the current study demonstrated that SPP1 exhibited significant diagnostic value for gastrointestinal tumors, which suggested that SPP1 may exhibit potential as a diagnostic marker of CRC, GC and EC. The present study provided a novel theoretical basis for the role of SPP1 as a diagnostic marker of digestive system tumors.

Inhibition of protein kinase C isozymes causes immune profile alteration and possibly decreased tumorigenesis in bladder cancer

Protein kinase C (PRKC) isozymes activate many signaling pathways and promote tumorigenesis, which can be confirmed by masking the kinase activity. In the present study, the kinase activity of PRKC ε and ζ isozymes was masked by siRNA in bladder cancer, and the consequent gene profile was evaluated. Here, we show that the commonly dysregulated genes affected by both the isozymes were the chemokines (CXCL8 & CXCL10), adhesion molecules (ICAM1, SPP1, MMP3, VEGFA) and mutated isoform of TP53. As these same genes were upregulated in bladder cancer patients, the activity of the kinase in downregulating them is confirmed. These genes are associated with regulating the tumor microenvironment, proliferation and differentiation of cancer cells and poor prognosis. The effect of kinase masking in downregulating these genes in bladder cancer indicates the benefits PRKC inhibitors may have in managing these patients.

SPP1 promotes radiation resistance through JAK2/STAT3 pathway in esophageal carcinoma

BACKGROUND

Therapeutic resistance to radiotherapy is one of the major obstacles in clinical practice that significantly affect the therapeutic efficiency and prognosis of human esophageal carcinoma (ESCA). Thus, it is critical to understand the molecular mechanisms of radiation resistance in ESCA. Secreted phosphoprotein 1 (SPP1) plays an essential role in various human cancers, but its role in radiation resistance remains unclear.

METHOD

Cell culture and transfection; Cell Counting Kit-8 (CCK-8) assays; EdU incorporation assays; Patient sample collection and medical records review; Transwell assays; Colony formation assays; Wound healing assays; Western blot; Immunofluorescence; Immunohistochemistry; Irradiation; Flow cytometry; Animal studies; Human Apoptosis Array Kit; Bioinformatics.

RESULT

In the current study, we reported the novel phenomenon that radiation-treated human ESCA cells upregulated SPP1 expression, which in turn contributed to the ESCA resistance to radiotherapy. We also reported the tumor-promoting effect of SPP1 in ESCA systematically and comprehensively. Furthermore, subsequent studies by knocking down or overexpressing SPP1 in human ESCA cells showed that SPP1 could facilitate the repair of DNA damage and the survival of tumor cells post-radiation in ESCA, which might contribute to the development of radiation resistance during the radiotherapy process. More detailed investigations on the downstream molecular pathway suggested that radiation could increase the phosphorylation level of JAK2 and STAT3 by increasing SPP1 expression. Further in vivo validation using a mouse ESCA xenograft model showed that SPP1 overexpression significantly increased tumor volume while either SPP1 knockdown or pharmacological inhibition of the JAK2-STAT3 pathway reduced tumor volume in a synergistic manner with radiotherapy.

CONCLUSION

Collectively, these findings suggested that the SPP1/JAK2/STAT3 axis is a critical player in ESCA progression and radiation resistance, which is a potential therapeutic target for combined therapy with the standard radiotherapy regimen to improve curative effect and increase patients' survival with ESCA.