The role of SOX18 in bladder cancer and its underlying mechanism in mediating cellular functions

TGF-β1-Induced SOX18 Elevation Promotes Hepatocellular Carcinoma Progression and Metastasis Through Transcriptionally Upregulating PD-L1 and CXCL12

BACKGROUND & AIMS

Hepatocellular carcinoma (HCC) is characterized by an immune-suppressive microenvironment, which contributes to tumor progression, metastasis, and immunotherapy resistance. Identification of HCC-intrinsic factors regulating the immunosuppressive microenvironment is urgently needed. Here, we aimed to elucidate the role of SYR-Related High-Mobility Group Box 18 (SOX18) in inducing immunosuppression and to validate novel combination strategies for SOX18-mediated HCC progression and metastasis.

METHODS

The role of SOX18 in HCC was investigated in orthotopic allografts and diethylinitrosamine/carbon tetrachloride-induced spontaneous models by using murine cell lines, adeno-associated virus 8, and hepatocyte-specific knockin and knockout mice. The immune cellular composition in the HCC microenvironment was evaluated by flow cytometry and immunofluorescence.

RESULTS

SOX18 overexpression promoted the infiltration of tumor-associated macrophages (TAMs) and regulatory T cells (Tregs) while diminishing cytotoxic T cells to facilitate HCC progression and metastasis in cell-derived allografts and chemically induced HCC models. Mechanistically, transforming growth factor-beta 1 (TGF-β1) upregulated SOX18 expression by activating the Smad2/3 complex. SOX18 transactivated chemokine (C-X-C motif) ligand 12 (CXCL12) and programmed death ligand 1 (PD-L1) to induce the immunosuppressive microenvironment. CXCL12 knockdown significantly attenuated SOX18-induced TAMs and Tregs accumulation and HCC dissemination. Antagonism of chemokine receptor 4 (CXCR4), the cognate receptor of CXCL12, or selective knockout of CXCR4 in TAMs or Tregs likewise abolished SOX18-mediated effects. TGFβR1 inhibitor Vactosertib or CXCR4 inhibitor AMD3100 in combination with anti-PD-L1 dramatically inhibited SOX18-mediated HCC progression and metastasis.

CONCLUSIONS

SOX18 promoted the accumulation of immunosuppressive TAMs and Tregs in the microenvironment by transactivating CXCL12 and PD-L1. CXCR4 inhibitor or TGFβR1 inhibitor in synergy with anti-PD-L1 represented a promising combination strategy to suppress HCC progression and metastasis.

Targeting SOX18 Transcription Factor Activity by Small-Molecule Inhibitor Sm4 in Non-Small Lung Cancer Cell Lines

The transcription factor SOX18 has been shown to play a crucial role in lung cancer progression and metastasis. In this study, we investigated the effect of Sm4, a SOX18 inhibitor, on cell cycle regulation in non-small cell lung cancer (NSCLC) cell lines LXF-289 and SK-MES-1, as well as normal human lung fibroblast cell line IMR-90. Our results demonstrated that Sm4 treatment induced cytotoxic effects on all three cell lines, with a greater effect observed in NSCLC adenocarcinoma cells. Sm4 treatment led to S-phase cell accumulation and upregulation of p21, a key regulator of the S-to-G2/M phase transition. While no significant changes in SOX7 or SOX17 protein expression were observed, Sm4 treatment resulted in a significant upregulation of SOX17 gene expression. Furthermore, our findings suggest a complex interplay between SOX18 and p21 in the context of lung cancer, with a positive correlation observed between SOX18 expression and p21 nuclear presence in clinical tissue samples obtained from lung cancer patients. These results suggest that Sm4 has the potential to disrupt the cell cycle and target cancer cell growth by modulating SOX18 activity and p21 expression. Further investigation is necessary to fully understand the relationship between SOX18 and p21 in lung cancer and to explore the therapeutic potential of SOX18 inhibition in lung cancer.

Targeting c-Met in the treatment of urologic neoplasms: Current status and challenges

At present, studies have found that c-Met is mainly involved in epithelial-mesenchymal transition (EMT) of tumor tissues in urologic neoplasms. Hepatocyte growth factor (HGF) combined with c-Met promotes the mitosis of tumor cells, and then induces motility, angiogenesis, migration, invasion and drug resistance. Therefore, c-Met targeting therapy may have great potential in urologic neoplasms. Many strategies targeting c-Met have been widely used in the study of urologic neoplasms. Although the use of targeting c-Met therapy has a strong biological basis for the treatment of urologic neoplasms, the results of current clinical trials have not yielded significant results. To promote the application of c-Met targeting drugs in the clinical treatment of urologic neoplasms, it is very important to study the detailed mechanism of c-Met in urologic neoplasms and innovate c-Met targeted drugs. This paper firstly discussed the value of c-Met targeted therapy in urologic neoplasms, then summarized the related research progress, and finally explored the potential targets related to the HGF/c-Met signaling pathway. It may provide a new concept for the treatment of middle and late urologic neoplasms.

c-Met: A Promising Therapeutic Target in Bladder Cancer

Mesenchymal-epithelial transition factor (c-Met) belongs to the tyrosine kinase receptor family and is overexpressed in various human cancers. Its ligand is hepatocyte growth factor (HGF), and the HGF/c-Met signaling pathway is involved in a wide range of cellular processes, including cell proliferation, migration, and metastasis. Emerging studies have indicated that c-Met expression is strongly associated with bladder cancer (BCa) development and prognosis. Therefore, c-Met is a potential therapeutic target for BCa treatment. Recently, the aberrant expression of noncoding RNAs was found to play a significant role in tumour progression. There is a close connection between c-Met and noncoding RNA. Herein, we summarized the biological function and prognostic value of c-Met in BCa, as well as its potential role as a drug target. The relation of c-Met and ncRNA was also described in the paper.

Identification of the Functions and Prognostic Values of RNA Binding Proteins in Bladder Cancer

Post-transcriptional regulation plays a leading role in gene regulation and RNA binding proteins (RBPs) are the most important posttranscriptional regulatory protein. RBPs had been found to be abnormally expressed in a variety of tumors and is closely related to its occurrence and progression. However, the exact mechanism of RBPs in bladder cancer (BC) is unknown. We downloaded transcriptomic data of BC from the Cancer Genome Atlas (TCGA) database and used bioinformatics techniques for subsequent analysis. A total of 116 differentially expressed RBPs were selected, among which 61 were up-regulated and 55 were down-regulated. We then identified 12 prognostic RBPs including CTIF, CTU1, DARS2, ENOX1, IGF2BP2, LIN28A, MTG1, NOVA1, PPARGC1B, RBMS3, TDRD1, and ZNF106, and constructed a prognostic risk score model. Based on this model we found that patients in the high-risk group had poorer overall survival (P < 0.001), and the area under the receiver operator characteristic curve for this model was 0.677 for 1 year, 0.697 for 3 years, and 0.709 for 5 years. Next, we drew a nomogram based on the risk score and other clinical variables, which showed better predictive performance. Our findings contribute to a better understanding of the pathogenesis, progression and metastasis of BC. The model of these 12 genes has good predictive value and may have good prospects for improving clinical treatment regimens and patient prognosis.

Transitional cell carcinoma matrix stiffness regulates the osteopontin and YAP expression in recurrent patients

Cells translate the mechanosensing of extracellular matrix component dysregulation and stiffness into the signal transduction including Osteopontin (OPN) through the Hippo pathway. But how extracellular matrix (ECM) component dysregulation and stiffness are ultimately linked to transitional cell carcinoma (TCC) development remains poorly understood. This study was aimed to evaluate the possible links between ECM component alteration after cancer surgery and OPN and Yes-associated protein (YAP) expression in TCC and adjacent tissues. In this study, we used 50 TCC (25 newly diagnosed and 25 recurrent) and 50 adjacent tissues to determine the tissue stiffness using atomic force microscopy. The mRNA expression of SPP1, Indian hedgehog (IHH), and YAP was also determined using qRT-PCR. Western blotting and ELISA were performed to assess the tissue and serum levels of OPN, respectively. To assess the glycoproteins and elastic fibers content, Periodic Acid Schiff, and Verhoeff-Van Gieson Staining were performed, respectively. Matrix stiffness was markedly higher in TCCs than adjacent tissues (p < 0.05). Gene expression analysis showed that YAP, SPP1, and IHH genes were upregulated in TCC tissues (p < 0.05). Additionally, the OPN protein overexpression was observed in the tissue and the serum of TCC patients (p < 0.05). We also found that glycoproteins, elastic fibers content of recurrent TCC tissues was remarkably higher as compared to adjacent tissues (p < 0.05). Our results suggest that glycoproteins and elastic fibers content modulation and ECM stiffness may upregulates the expression of YAP, SPP1 and IHH genes, and possibly contribute to the TCC development and relapse.

SOX18 enhances the proliferation and migration of airway smooth muscle cells induced by tumor necrosis factor-α via the regulation of Notch1 signaling

Childhood asthma is a frequent chronic disease of pediatric populations. The excessive proliferation and migration of airway smooth muscle cells contribute to airway remodeling during asthma pathogenesis. Sex-determining region on the Y chromosome-related high mobility group box 18 (SOX18) has been reported to be over-expressed in asthma. However, whether SOX18 plays a role in modulating the airway remodeling of asthma is not fully understood. The purposes of this work were to assess the potential role of SOX18 in modulating airway remodeling using tumor necrosis factor-α (TNF-α)-stimulated airway smooth muscle cells in vitro. Our results showed that SOX18 expression was increased following TNF-α stimulation in airway smooth muscle cells. The silencing of SOX18 markedly prohibited the proliferation and migration of airway smooth muscle cells induced by TNF-α, whilst the over-expression of SOX18 produced the opposite effects. Further investigation revealed that SOX18 promoted the expression of Notch1, and enhanced the activation of Notch1 signaling in airway smooth muscle cells stimulated by TNF-α. The inhibition of Notch1 markedly diminished SOX18-over-expression-evoked promotion effects on TNF-α-induced proliferation and migration of airway smooth muscle cells. In addition, the reactivation of Notch1 signaling markedly reversed the SOX18-silencing-induced suppressive effect on the TNF-α-induced proliferation and the migration of airway smooth muscle cells. In summary, the findings of this work demonstrate that SOX18 regulates the proliferation and migration of airway smooth muscle cells induced by TNF-α via the modulation of Notch1 signaling. This study indicates a potential role for SOX18 in promoting airway remodeling during asthma pathogenesis.

The role of SOX family transcription factors in gastric cancer

Gastric cancer (GC) is a leading cause of death worldwide. GC is the third-most common cause of cancer-related death after lung and colorectal cancer. It is also the fifth-most commonly diagnosed cancer. Accumulating evidence has revealed the role of signaling networks in GC progression. Identification of these molecular pathways can provide new insight into therapeutic approaches for GC. Several molecular factors involved in GC can play both onco-suppressor and oncogene roles. Sex-determining region Y (Sry)-box-containing (SOX) family members are transcription factors with a well-known role in cancer. SOX proteins can bind to DNA to regulate cellular pathways via a highly conserved domain known as high mobility group (HMG). In the present review, the roles of SOX proteins in the progression and/or inhibition of GC are discussed. The dual role of SOX proteins as tumor-promoting and tumor-suppressing factors is highlighted. SOX members can affect upstream mediators (microRNAs, long non-coding RNAs and NF-κB) and down-stream mediators (FAK, HIF-1α, CDX2 and PTEN) in GC. The possible role of anti-tumor compounds to target SOX pathway members in GC therapy is described. Moreover, SOX proteins may be used as diagnostic or prognostic biomarkers in GC.

SOX18 exerts tumor-suppressive functions in papillary thyroid carcinoma through inhibition of Wnt/β-catenin signaling

Sex-determining region on the Y chromosome-related high mobility group box 18 (SOX18) has emerged as a key tumor-related protein in a wide range of human tumors. Yet, the involvement of SOX18 in papillary thyroid carcinoma has not been determined. This study aimed to explore the expression and biological function of SOX18 in papillary thyroid carcinoma. There was a significant decrease in SOX18 expression in papillary thyroid carcinoma tissues compared with that in normal tissues. Low expression of SOX18 was also detected in papillary thyroid carcinoma cell lines and upregulation of SOX18 effectively repressed the proliferative, colony-forming and invasive abilities of papillary thyroid carcinoma cells in vitro. In contrast, knockdown of SOX18 in papillary thyroid carcinoma cells was associated with a significant increase in cell proliferation and invasion. Further studies revealed that SOX18 upregulation was associated with the reduced nuclear accumulation of β-catenin and the downregulation of Wnt/β-catenin signaling in thyroid carcinoma cells. Moreover, inhibition of Wnt/β-catenin signaling markedly attenuated SOX18 knockdown-evoked oncogenic effects in papillary thyroid carcinoma cells. In addition, SOX18 overexpression remarkably retarded the tumor growth of papillary thyroid carcinoma cell-derived xenograft tumors in nude mice. Taken together, these results demonstrate that SOX18 suppresses the proliferation and invasion of papillary thyroid carcinoma by inhibiting Wnt/β-catenin signaling. Our study reveals a tumor-suppressive role of SOX18 in papillary thyroid carcinoma and suggests that SOX18 is an attractive candidate target for treatment of papillary thyroid carcinoma.

SLC12A5 interacts and enhances SOX18 activity to promote bladder urothelial carcinoma progression via upregulating MMP7

Solute carrier family 12 member 5 (SLC12A5) has an oncogenic role in bladder urothelial carcinoma. The present study aimed to characterize the molecular mechanisms of SLC12A5 in bladder urothelial carcinoma pathogenesis. Functional assays identified that in bladder urothelial carcinoma SLC12A5 interacts with and stabilizes SOX18, and then upregulates matrix metalloproteinase 7 (MMP7). In vivo and in vitro assays were performed to confirm the effect of SLC12A5’s interaction with SOX18 on MMP7‐mediated bladder urothelial carcinoma progression. SLC12A5 was upregulated in human bladder tumors, and correlated with the poor survival of patients with bladder urothelial carcinoma tumor invasion and metastasis, promoted by SLC12A5 overexpression. We demonstrated that SLC12A5 interacted with SOX18, and then upregulated MMP7, thus enhancing tumor progression. Importantly, SLC12A5 expression correlated positively with SOX18 and MMP7 expression in bladder urothelial carcinoma. Furthermore, SLC12A5 expression was suppressed by miR‐133a‐3p. Ectopic expression of SLC12A5 partly abolished miR‐133a‐3p‐mediated suppression of cell migration. SLC12A5‐SOX18 complex‐mediated upregulation on MMP7 was important in bladder urothelial carcinoma progression. The miR‐133a‐3p/SLC12A5/SOX18/MMP7 signaling axis was critical for progression, and provided an effective therapeutic approach against bladder urothelial carcinoma.