SALL4 promotes the tumorigenicity of cervical cancer cells through activation of the Wnt/β-catenin pathway via CTNNB1

Long non-coding RNA NEAT1 promotes aerobic glycolysis and progression of cervical cancer through WNT/β-catenin/PDK1 axis

BACKGROUND

Cervical cancer is one of the most common gynecological cancers. Accumulated evidence shows that long non-coding RNAs (lncRNAs) play essential roles in cervical cancer occurrence and progression, but their specific functions and mechanisms remain to be further explored.

METHODS

The RT-qPCR assay was used to detect the expression of NEAT1 in cervical cancer tissues and cell lines. CCK-8, colony formation, flow cytometry, western blotting, and Transwell assays were used to evaluate the impact of NEAT1 on the malignant behavior of cervical cancer cells. Glucose consumption, lactate production, ATP levels, ROS levels, MMP levels, and the mRNA expressions of glycolysis-related genes and tricarboxylic acid cycle-related genes were detected to analyze the effect of NEAT1 on metabolism reprograming in cervical cancer cells. The expressions of PDK1, β-catenin and downstream molecules of the WNT/β-catenin signaling pathway in cervical cancer cells and tissues were detected by western blotting, RT-qPCR, immunofluorescence and immunohistochemistry assays.

RESULTS

This study investigated the role and possible molecular mechanism of lncRNA nuclear paraspeckle assembly transcript 1 (NEAT1) in cervical cancer. Our results showed that NEAT1 was highly expressed in cervical cancer tissues and cell lines. Downregulation of NEAT1 inhibited the proliferation, migration, invasion and glycolysis of cervical cancer cells, while overexpression of NEAT1 led to the opposite effects. Mechanistically, NEAT1 upregulated pyruvate dehydrogenase kinase (PDK1) through the WNT/β-catenin signaling pathway, which enhanced glycolysis and then facilitated cervical cancer metastasis. Furthermore, NEAT1 maintained the protein stability of β-catenin but did not affect its mRNA level. We also excluded the direct binding of NEAT1 to the β-catenin protein via RNA pull-down assay. The suppressive impact of NEAT1 knockdown on cell proliferation, invasion, and migration was rescued by β-catenin overexpression. The WNT inhibitor iCRT3 attenuated the carcinogenic effect induced by NEAT1 overexpression.

CONCLUSION

In summary, these findings indicated that NEAT1 may contribute to the progression of cervical cancer by activating the WNT/β-catenin/PDK1 signaling axis.

SALL4 in gastrointestinal tract cancers: upstream and downstream regulatory mechanisms

Effective therapeutic targets and early diagnosis are major challenges in the treatment of gastrointestinal tract (GIT) cancers. SALL4 is a well-known transcription factor that is involved in organogenesis during embryonic development. Previous studies have revealed that SALL4 regulates cell proliferation, survival, and migration and maintains stem cell function in mature cells. Additionally, SALL4 overexpression is associated with tumorigenesis. Despite its characterization as a biomarker in various cancers, the role of SALL4 in GIT cancers and the underlying mechanisms are unclear. We describe the functions of SALL4 in GIT cancers and discuss its upstream/downstream genes and pathways associated with each cancer. We also consider the possibility of targeting these genes or pathways as potential therapeutic options for GIT cancers.

Downregulation of LAMB3 Altered the Carcinogenic Properties of Human Papillomavirus 16-Positive Cervical Cancer Cells

Nearly all cervical cancer cases are caused by infection with high-risk human papillomavirus (HR-HPV) types. The mechanism of cervical cell transformation is related to the powerful action of viral oncoproteins and cellular gene alterations. Transcriptomic data from cervical cancer and normal cervical cells were utilized to identify upregulated genes and their associated pathways. The laminin subunit beta-3 (LAMB3) mRNAwas overexpressed in cervical cancer and was chosen for functional analysis. The LAMB3 was predominantly expressed in the extracellular region and the plasma membrane, which play a role in protein binding and cell adhesion molecule binding, leading to cell migration and tissue development. LAMB3 was found to be implicated in the pathway in cancer and the PI3K-AKT signaling pathway. LAMB3 knockdown decreased cell migration, invasion, anchorage-dependent and anchorage-independent cell growth and increased the number of apoptotic cells. These effects were linked to a decrease in protein levels involved in the PI3K-AKT signaling pathway and an increase in p53 protein. This study demonstrated that LAMB3 could promote cervical cancer cell migration, invasion and survival.

SALL4 is a CRL3REN/KCTD11 substrate that drives Sonic Hedgehog-dependent medulloblastoma

The Sonic Hedgehog (SHH) pathway is crucial regulator of embryonic development and stemness. Its alteration leads to medulloblastoma (MB), the most common malignant pediatric brain tumor. The SHH-MB subgroup is the best genetically characterized, however the molecular mechanisms responsible for its pathogenesis are not fully understood and therapeutic benefits are still limited. Here, we show that the pro-oncogenic stemness regulator Spalt-like transcriptional factor 4 (SALL4) is re-expressed in mouse SHH-MB models, and its high levels correlate with worse overall survival in SHH-MB patients. Proteomic analysis revealed that SALL4 interacts with REN/KCTD11 (here REN), a substrate receptor subunit of the Cullin3-RING ubiquitin ligase complex (CRL3REN) and a tumor suppressor lost in ~30% of human SHH-MBs. We demonstrate that CRL3REN induces polyubiquitylation and degradation of wild type SALL4, but not of a SALL4 mutant lacking zinc finger cluster 1 domain (ΔZFC1). Interestingly, SALL4 binds GLI1 and cooperates with HDAC1 to potentiate GLI1 deacetylation and transcriptional activity. Notably, inhibition of SALL4 suppresses SHH-MB growth both in murine and patient-derived xenograft models. Our findings identify SALL4 as a CRL3REN substrate and a promising therapeutic target in SHH-dependent cancers.

The analysis of HPV integration sites based on nanopore sequencing and the profiling changes along the course of photodynamic therapy

OBJECTIVE

To detect the HPV genotype and integration sites in patients with high-risk HPV infection at different stages of photodynamic therapy using nanopore technology and to evaluate the treatment effect.

METHODS

Four patients with HPV infection were selected and subjected to photodynamic therapy, and cervical exfoliated cell was sampled at before treatment, after three courses of treatment and six courses of treatment, their viral abundance and insertion sites were analyzed by nanopore technology, and pathological examinations were performed before and after treatment. In this study, we developed a novel assay that combined viral sequence enrichment and Nanopore sequencing for identification of HPV genotype and integration sites at once. The assay has obvious advantages over qPCR or NGS-based methods, as it has better sensitivity after viral sequences enrichment and can generate long-reads (kb to Mb) for better detection rate of structure variations, moreover, fast turn-around time for real-time viral sequencing and analysis.

RESULTS

The pathological grade was reduced in all four patients after photodynamic therapy. Virus has been cleared in two cases after treatment, the virus amount reduced after treatment but not completely cleared in one case, and two type viruses were cleared and one type virus persisted after treatment in the last patient with multiple infection. Viral abundance and the number of integration sites were positively correlated. Gene enrichment analysis showed complete viral clearance in 1 patient and 3 patients required follow-up.

CONCLUSION

Nanopore sequencing can effectively monitor the abundance of HPV viruses and integration sites to show the presence status of viruses, and combined with the results of gene enrichment analysis, the treatment effect can be dynamically assessed.

On a sugar high: Role of O-GlcNAcylation in cancer

Recent advances in the understanding of the molecular mechanisms underlying cancer progression have led to the development of novel therapeutic targeting strategies. Aberrant glycosylation patterns and their implication in cancer have gained increasing attention as potential targets due to the critical role of glycosylation in regulating tumor-specific pathways that contribute to cancer cell survival, proliferation, and progression. A special type of glycosylation that has been gaining momentum in cancer research is the modification of nuclear, cytoplasmic, and mitochondrial proteins, termed O-GlcNAcylation. This protein modification is catalyzed by an enzyme called O-GlcNAc transferase (OGT), which uses the final product of the Hexosamine Biosynthetic Pathway (HBP) to connect altered nutrient availability to changes in cellular signaling that contribute to multiple aspects of tumor progression. Both O-GlcNAc and its enzyme OGT are highly elevated in cancer and fulfill the crucial role in regulating many hallmarks of cancer. In this review, we present and discuss the latest findings elucidating the involvement of OGT and O-GlcNAc in cancer.

SALL4 advances the proliferation and tumor cell stemness of colon cancer cells through the transcription and regulation of ROBO2

SALL4 is a transcription factor highly expressed in diverse cancers and is implicated in the development of cancer. SALL4 has been implied to play a cancer-promoting role in colon cancer (CC), but the molecular mechanism remains unclear. Chromatin immunoprecipitation assay and dual-luciferase assay were conducted to verify the binding relationship of SALL4 and ROBO2. qRT-PCR detected the mRNA expression levels of SALL4 and ROBO2, and the flow cytometry analyzed the cell cycle distribution. Western blot examined SALL4 expression, and cell cycle/cell stemness-related proteins. The impact of SALL4 and ROBO2 on the proliferation capacity of cells and tumor cell stemness was elucidated by MTT, colony formation, and sphere-forming assays. SALL4 and ROBO2 were up-regulated in CC, and SALL4 could activate the transcription of ROBO2. Down-regulated SALL4 was able to significantly restrain the proliferation capacity of CC cells and arrest the cell cycle in G0/G1 phase by repressing the expression of cyclin B, cyclin E, and cyclin D1. Besides, the rescue assay results indicated that up-regulated ROBO2 could reverse the repressive impact of down-regulated SALL4 on the proliferation of CC cells and accelerate the progression of the cell cycle, thus promoting the sphere-forming of tumor stem cells. SALL4 advanced the proliferation of CC and cell stemness through direct activation of ROBO2 expression, implied the novel mechanism of SALL4 in CC, and pointed out that SALL4/ROBO2 axis was likely to be a potential target for clinical treatment of CC.

SNHG1 functions as a ceRNA in hypertrophic scar fibroblast proliferation and apoptosis through miR-320b/CTNNB1 axis

Hypertrophic scar (HS) is a fibrotic disease caused by skin injury. Competing endogenous RNA (ceRNA) has been demonstrated to implicate in the regulation of cell malignant phenotypes. This research aims to reveal the effect of catenin beta 1 (CTNNB1) on the functions of hypertrophic scar fibroblasts (HSFBs) and its role in a ceRNA network. RNA expression level was assessed by quantitative reverse transcription polymerase chain reaction (RT-qPCR). The proliferation and apoptosis of HSFB was detected via Cell Counting Kit-8 (CCK-8) assay and flow cytometry analysis. Mechanism experiments included RNA pull down assay, luciferase reporter assay and RNA-binding protein immunoprecipitation (RIP) assay were applied to analyze the upstream molecular mechanism of CTNNB1. CTNNB1 was highly expressed in HSFB. CTNNB1 depletion repressed malignant growth of HSFB. Mechanically, CTNNB1 was targeted by microRNA-320b (miR-320b) in HSFB. Small nucleolar RNA host gene 1 (SNHG1) aced as a ceRNA to upregulate CTNNB1 expression via sponging miR-320b in HSFB. CTNNB1 overexpression could reverse the impact of SNHG1 depletion on the proliferation and apoptosis of HSFB. SNHG1 acts as a ceRNA in modulating HSFB proliferation and apoptosis through miR-320b/CTNNB1 axis. SNHG1 act as a ceRNA to promote HSFB growth by sponging miR-320b to upregulate CTNNB1.

Dual-Regulated Mechanism of EZH2 and KDM6A on SALL4 Modulates Tumor Progression via Wnt/β-Catenin Pathway in Gastric Cancer

BACKGROUND

SALL4 has been demonstrated in many cancers and participated in tumorigenesis and tumor progression, however, its expression and function still remain ambiguous in GC, especially its upstream mechanistic modulators.

PURPOSE

We explored whether the dual mediation of EZH2 and KDM6A could be involved in upstream regulation of SALL4, which promotes GC cell progression via the Wnt/β-catenin pathway.

METHOD

Analysis of discrepant gene expression in GC and normal gastric tissues from The Cancer Genome Atlas (TCGA) dataset. GC cell lines were transfected by siEZH2 and siKDM6A, the transduction molecules of KDM6A/EZH2-SALL4-β-catenin signaling were quantified in the GC cells.

RESULTS

Here, we showed that only SALL4 levels of SALL family members were upregulated in nonpaired and paired GC tissues than those in corresponding normal tissues and were associated with its histological types, pathological stages, TNM stages including T stage (local invasion), N stage (lymph node metastasis), M stage (distant metastasis), and overall survival from the TCGA dataset. SALL4 level was elevated in GC cells compared to normal gastric epithelial cell line (GES-1) and was correlated to cancer cell progression and invasion through the Wnt/β-catenin pathway in GC, which levels would be separately upregulated or downregulated by KDM6A or EZH2.

CONCLUSION

We first proposed and demonstrated that SALL4 promoted GC cell progression via the Wnt/β-catenin pathway, which was mediated by the dual regulation of EZH2 and KDM6A on SALL4. This mechanistic pathway in gastric cancer represents a novel targetable pathway.

LncRNA HCP5 acts as a miR-128-3p sponge to promote the progression of multiple myeloma through activating Wnt/β-catenin/cyclin D1 signaling via PLAGL2

BACKGROUND

Although long non-coding RNA (lncRNA) HCP plays essential roles in human cancers, its function and mechanism in multiple myeloma (MM) have not crystallized.

METHODS

HCP5 level in MM was assessed through qRT-PCR. A series of functional investigations were conducted to evaluate the influences of HCP5 on proliferation and apoptosis. Bioinformatics analysis and RIP/RNA pull-down assays were carried out to determine the relationships among HCP5, miR-128-3p, and PLAGL2. Relative protein level was determined through Western blot. A xenograft tumor model was applied for validating the roles of HCP5/miR-128-3p/PLAGL2 axis in vivo.

RESULTS

HCP5 was significantly increased in MM. HCP5 knockdown effectively thwarted the proliferative rate and cell cycle of MM cell lines and suppressed tumor growth. HCP5 regulated PLAGL2 expression by sponging miR-128-3p. PLAGL2 overexpression effectively rescued cells from influences by sh-HCP5 on cell proliferative and apoptotic rates. Additionally, HCP5 knockdown significantly inhibited Wnt/β-catenin/cyclin D1 signaling, and these effects were eliminated by PLAGL2 overexpression.

CONCLUSION

Our study revealed that HCP5/miR-128-3p/PLAGL2 is closely correlated to MM development by modulating Wnt/β-catenin/cyclin D1 signaling. HCP5 promoted cell proliferation and tumor formation of MM cells by activating the Wnt/β-catenin/CCND1 signaling pathway by sponging miR-128-3p to increase PLAGL2 expression.

Vitamin D Receptor Gene Polymorphisms and the Risk of CIN2+ in Shanxi Population

Cervical cancer is one of the most common malignancies in women with high morbidity and mortality. Human papillomavirus (HPV) infection is the primary cause of cervical cancer, of which HPV 16 is the predominant. Early detection and effective treatment of cervical precancerous lesions are the key to preventing cervical cancer. Vitamin D receptor (VDR) gene polymorphism is considered to be an important cause of cancer development. Here, we studied the association of VDR polymorphisms (FOKI, BsmI, ApaI, and TaqI) in HPV16-positive cervical intraepithelial neoplasia (CIN)2+ patients. HPV16-positive patients who visited the Colposcopy Clinic of Obstetrics and Gynecology, the Second Hospital of Shanxi Medical University for biopsy due to abnormal HPV and/or Thinprep cytologic test (TCT) from September 1, 2020 to October 1, 2021 were grouped by pathological results. The fasting blood samples were collected and VDR polymorphisms were detected using TaqMan fluorescent probes, and the three sites of BsmI-ApaI-TaqI were subjected to haplotype analysis. FOKI ff genotype (OR = 2.01; 95% CI = 1.12 - 3.59; p = 0.019) and f allele (OR = 1.48; 95% CI = 1.10 - 1.98; p = 0.009) were found to be associated with the risk of CIN2+. TaqI Tt genotype (OR = 2.03; 95% CI = 1.20 - 3.43; p = 0.008), tt genotype (OR = 2.09; 95% CI = 1.09 - 4.02; p = 0.028), and t allele (OR = 1.35; 95% CI = 1.01 - 1.80; p = 0.041) were associated with the risk of CIN2+. No haplotype was associated with CIN2+ risk. According to the results, FOKI and TaqI polymorphisms are associated with CIN2+ risk.

FAM201A Promotes Cervical Cancer Progression and Metastasis through miR-1271-5p/Flotillin-1 Axis Targeting-Induced Wnt/β-Catenin Pathway

This study investigated the role of the family with sequence similarity 201-member A (FAM201A), as previously reported oncogenic, in cervical cancer (CC). FAM201A expression in CC was analyzed through bioinformatics analyses, and its distribution in CC tissues/cells was determined by in situ hybridization. CC cells were transfected/cotransfected with FAM201A/flotillin-1 (FLOT1) overexpression plasmids and miR-1271-5p mimics, followed by functional analysis on viability, migration and invasion. Pearson's correlation tests were performed to analyze the correlation between FAM201A and miR-1271-5p in CC tissues. The targeting relationship between miR-1271-5p and FLOT1 was confirmed by dual-luciferase reporter assay. The expressions of FAM201A, miR-1271-5p, FLOT1, matrix metalloproteinases (MMP)-9, MMP-2, E-cadherin, N-cadherin, and the Wnt/β-catenin pathway-related molecules (Wnt1, β-catenin and p-β-catenin) in CC cells or tissues were assessed by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and/or western blot. The results showed that FAM201A was abundantly expressed and miR-1271-5p expression was downregulated in CC. FAM201A was enriched in CC cell cytoplasm and negatively correlated with miR-1271-5p in CC tissues. FAM201A overexpression enhanced the cell viability, migration, invasion, and tumorigenesis of CC in vivo and increased FLOT1 expression. These trends were all reversed by upregulating miR-1271-5p, which induced opposite effects to FAM201A overexpression. MiR-1271-5p upregulation depleted the levels of MMP-9, MMP-2, N-cadherin, and the Wnt/β-catenin pathway-related molecules and upregulated E-cadherin expression. FLOT1 was a direct target of miR-1271-5p. FLOT1 overexpression induced effects contrary to the upregulation of miR-1271-5p and abolished miR-1271-5p upregulation-induced effects in CC cells. Overall, this study showed that FAM201A promoted cervical cancer progression and metastasis by targeting the miR-1271-5p/FLOT1 axis-induced Wnt/β-catenin pathway.

Co-overexpression of self-renewal markers SALL4 and HIWI is correlated with depth of tumor invasion and metastasis in colorectal cancer

Background

SALL4 and HIWI are involved in the maintenance of self-renewal capacity of stem cells. Several scrutinizes have demonstrated that SALL4 and HIWI play a key role in cancer development. However, the correlation between these genes regarding different clinicopathological features of patients with colorectal cancer (CRC) is still unclear.

Methods

The expression of SALL4 and HIWI in different clinicopathological features of 46 CRC patients was analyzed using relative comparative real-time PCR.

Results

mRNA expression levels of SALL4 and HIWI genes were significantly correlated with each other in CRC (P = 0.013, Pearson correlation = 0.364). HIWI expression was notably increased in tumors with overexpression of SALL4 in comparison with other samples. This correlation was significant in non-metastatic CRCs compared to the metastatic tumors and in invaded tumors to the serosa (T3/T4) in comparison with non-invaded tumors (T1/T2).

Conclusions

Based on the significant association of SALL4 and HIWI in different indices of CRC poor prognosis, it may be concluded that simultaneous expression of these genes is notably contributed to the growth and development of the disease, and therefore, their co-overexpression may be considered for prognosis of aggressive CRCs.

The Invasion and Metastasis of Colon Adenocarcinoma (COAD) Induced by SALL4

Objective

The development and progression of many cancers may be related to SALL4, the role and molecular mechanism of which are unclear in colon adenocarcinoma (COAD).

Methods

The SALL4 expression in adjacent normal mucosa tissues and carcinoma tissues of patients with COAD was detected through bioinformatic analysis based on TCGA database and immunohistochemistry. Single-cell analysis showed that the expression of SALL4 in normal tissue was noticeably low. GSEA analysis suggested that the SALL4 upregulated the GO and pathway of growth and cancer development and downregulated metabolization pathway. The relationship between lymph node metastasis, histological grading, clinical staging, and the expression of SALL4 in carcinoma tissues was analyzed. The upregulated or downregulated SALL4 expression of COAD cell lines was established. The influence of SALL4 on COAD cells invasion and proliferation was detected using plate cloning assay and Transwell. The expressions of EMT-related proteins E-cadherin, N-cadherin, vimentin, and Twist were detected by Western blot. The EMT phenotype was analyzed by immunofluorescence.

Results

The study confirmed that the expression of SALL4 was upregulated in COAD and positively correlated with the degree of tumor differentiation, tumor staging, and metastasis. The overexpression of SALL4 was related to a poor prognosis, promoted the invasion and proliferation of colorectal cancer cells, and accelerated the occurrence of EMT, which was characterized by upregulation of Twist, vimentin, and N-cadherin expressions and downregulation of E-cadherin. The immunofluorescence staining confirmed the EMT phenotype. On the contrary, knocking out SALL4 gene reversed EMT, weakened cell proliferation and invasion, inhibited upregulation of Twist, vimentin, and N-cadherin expressions and downregulation of E-cadherin.

Conclusion

To sum up, TNM grading, histological grading, and lymphatic metastasis were significantly correlated with SALL4 in tumor tissues. SALL4 played a vital role in tumor proliferation, invasion, and tumor EMT and may be a novel target for COAD.

LINC01315 accelerates the growth and epithelial-mesenchymal transition of colorectal cancer cells via activating the Wnt/β-catenin signal

The pathological roles of long non-coding RNAs (lncRNAs) in colorectal carcinoma (CRC) have been corroborated. To date, the pathological contributions of LINC01315 in the epithelial-mesenchymal transition (EMT) property of CRC are still ambiguous. By silencing LINC01315, we disclosed that LINC01315 promoted the growth, metastatic characteristics, and the EMT of CRC cells in vitro. Mechanistically, LINC01315 activated Wnt/β-catenin signaling. LINC01315 bound to the β-catenin promoter and activated its transcription. In rescue experiments, ectopic overexpression of β-catenin counteracted the inhibiting effector-triggered by LINC01315 deletion. In summary, this preliminary study brings new insights to the pathological significance of the LINC01315/Wnt/β-catenin signaling pathway in CRC.

SALL4 Oncogenic Function in Cancers: Mechanisms and Therapeutic Relevance

SALL4, a member of the SALL family, is an embryonic stem cell regulator involved in self-renewal and pluripotency. Recently, SALL4 overexpression was found in malignant cancers, including lung cancer, hepatocellular carcinoma, breast cancer, gastric cancer, colorectal cancer, osteosarcoma, acute myeloid leukemia, ovarian cancer, and glioma. This review updates recent advances of our knowledge of the biology of SALL4 with a focus on its mechanisms and regulatory functions in tumors and human hematopoiesis. SALL4 overexpression promotes proliferation, development, invasion, and migration in cancers through activation of the Wnt/β-catenin, PI3K/AKT, and Notch signaling pathways; expression of mitochondrial oxidative phosphorylation genes; and inhibition of the expression of the Bcl-2 family, caspase-related proteins, and death receptors. Additionally, SALL4 regulates tumor progression correlated with the immune microenvironment involved in the TNF family and gene expression through epigenetic mechanisms, consequently affecting hematopoiesis. Therefore, SALL4 plays a critical oncogenic role in gene transcription and tumor growth. However, there are still some scientific hypotheses to be tested regarding whether SALL4 is a therapeutic target, such as different tumor microenvironments and drug resistance. Thus, an in-depth understanding and study of the functions and mechanisms of SALL4 in cancer may help develop novel strategies for cancer therapy.

SALL Proteins; Common and Antagonistic Roles in Cancer

Simple Summary

Transcription factors play essential roles in regulating gene expression, impacting the cell phenotype and function, and in the response of cells to environmental conditions. Alterations in transcription factors, including gene amplification or deletion, point mutations, and expression changes, are implicated in carcinogenesis, cancer progression, metastases, and resistance to cancer treatments. Not surprisingly, transcription factor activity is altered in numerous cancers, representing a unique class of cancer drug targets. This review updates and integrates information on the SALL family of transcription factors, highlighting the synergistic and/or antagonistic functions they perform in various cancer types.

Abstract

SALL proteins are a family of four conserved C2H2 zinc finger transcription factors that play critical roles in organogenesis during embryonic development. They regulate cell proliferation, survival, migration, and stemness; consequently, they are involved in various human genetic disorders and cancer. SALL4 is a well-recognized oncogene; however, SALL1–3 play dual roles depending on the cancer context and stage of the disease. Current reviews of SALLs have focused only on SALL2 or SALL4, lacking an integrated view of the SALL family members in cancer. Here, we update the recent advances of the SALL members in tumor development, cancer progression, and therapy, highlighting the synergistic and/or antagonistic functions they perform in similar cancer contexts. We identified common regulatory mechanisms, targets, and signaling pathways in breast, brain, liver, colon, blood, and HPV-related cancers. In addition, we discuss the potential of the SALL family members as cancer biomarkers and in the cancer cells’ response to therapies. Understanding SALL proteins’ function and relationship will open new cancer biology, clinical research, and therapy perspectives.

The RNA N6-Methyladenosine Demethylase FTO Promotes Head and Neck Squamous Cell Carcinoma Proliferation and Migration by Increasing CTNNB1

Objective

In this study, we aimed to investigate the role of RNA N6-methyladenosine demethylase fat mass and obesity-associated protein (FTO) in head and neck squamous cell carcinoma (HNSCC).

Methods

Clinical data downloaded from The Cancer Genome Atlas (TCGA) database were used to analyze the relationship between mRNA levels of FTO, METTL3, METTL14, and ALKBH5, and the overall survival in cancer and para-cancer datasets. FTO expression in tumor and normal tissues was compared using immunohistochemistry, and its relationship with overall survival was analyzed based on the Kaplan–Meier method. The FaDu cell line with high FTO levels was chosen from five HNSCC cell lines for further experiments. FTO was verified as an oncogene in HNSCC by in vitro loss-of-function and overexpression studies, cell proliferation assay, wound healing assay, and identification of expression changes of epithelial–mesenchymal transition (EMT)-related markers. Catenin beta 1 (CTNNB1) was confirmed as a downstream target gene of FTO with additional methods like the GEPIA online tool, qRT-PCR, Western blotting, and dot blot assay.

Results

We found that FTO expression was significantly upregulated in HNSCC datasets and tissues. Increased FTO expression indicated a trend towards poor prognosis and was found to promote disease proliferation and migration. Mechanistically, cell proliferation assay, wound healing assay, and identification of expression changes of EMT-related markers demonstrated that FTO could act as an oncogene in HNSCC. FTO expression was significantly correlated with CTNNB1 expression. Moreover, it exerted a tumorigenic effect by increasing CTNNB1 expression in an m⁶A-dependent manner.

Conclusion

FTO promotes head and neck squamous cell carcinoma proliferation and migration by increasing CTNNB1 in an m⁶A-dependent manner.

A pan-cancer study of spalt-like transcription factors 1/2/3/4 as therapeutic targets

Spalt-like transcription factors (SALLs) are evolutionarily conserved proteins that participate in embryonic development. Four members of the SALL family, SALL1, SALL2, SALL3, and SALL4, are involved in cellular apoptosis, angiogenesis, invasion, and metastasis of tumors. We used the TCGA pan-cancer data to conduct a comprehensive analysis of SALL genes. High heterogeneity in the expression of these genes was observed across various cancers, SALL1 and SALL2 were downregulated, whereas SALL4 was upregulated. Moreover, we verified that SALL4 was commonly associated with survival disadvantage, whereas others were linked to a better prognosis. In renal cancer, SALL1, SALL2, and SALL3 showed downregulation, suggesting that they acted as tumor suppressors. Furthermore, SALLs were associated with immune infiltrate subtypes, with a close association between different degrees of infiltration of stromal cells and immune cells. DNA and RNA analyses in different tumors suggested different degrees of negative or positive correlation with tumor stem cell-like features. Finally, we revealed that SALLs were related to cancer cell resistance. Our results highlight the necessity to further study each SALL gene as a separate entity in specific types of cancer. Although this article showed that SALLs could be promising targets for cancer therapy, it needs further studies to validate the findings.

Osthole Induces Apoptosis and Inhibits Proliferation, Invasion, and Migration of Human Cervical Carcinoma HeLa Cells

Purpose

To study the effect of osthole extract on proliferation, migration, invasion, and apoptosis of human cervical carcinoma HeLa cells and investigate its underlying mechanism.

Methods

HeLa cells were exposed to osthole at various concentrations. Cell viability, migration, and invasion were detected by MTT assay, scratch wound-healing assay, and invasion assay, respectively. The proportion of cells undergoing apoptosis was analyzed by flow cytometry. Western blot and RT-qPCR were performed to determine changes in the expression of key factors in the Wnt/β-catenin signaling pathway.

Results

The osthole extract effectively inhibited the proliferation, migration, and invasion potential of HeLa cells in a dose-dependent manner. The rate of apoptosis induction in HeLa cells treated with the osthole extract for 48 h was significantly higher than that of the untreated controls. Outcomes of the western blotting analysis and RT-qPCR showed that the expression of β-catenin, c-Myc, cyclin D1, survivin, and MMP-9 was significantly inhibited.

Conclusion

Osthole could significantly inhibit the malignant behavior of HeLa cells and induce cellular apoptosis. Inactivation of the Wnt/β-catenin signaling pathway by osthole may be a mechanism to control cancer metastasis.

Exosomal microRNA-15a from mesenchymal stem cells impedes hepatocellular carcinoma progression via downregulation of SALL4

Hepatocellular carcinoma (HCC) is a heterogeneous tumor with an increased incidence worldwide accompanied by high mortality and dismal prognosis. Emerging evidence indicates that mesenchymal stem cells (MSCs)-derived exosomes possess protective effects against various human diseases by transporting microRNAs (miRNAs or miRs). We aimed to explore the role of exosomal miR-15a derived from MSCs and its related mechanisms in HCC. Exosomes were isolated from transduced MSCs and co-incubated with Hep3B and Huh7 cells. miR-15a expression was examined by RT-qPCR in HCC cells, MSCs, and secreted exosomes. CCK-8, transwell, and flow cytometry were used to detect the effects of miR-15a or spalt-like transcription factor 4 (SALL4) on cell proliferative, migrating, invasive, and apoptotic properties. A dual-luciferase reporter gene assay was performed to validate the predicted targeting relationship of miR-15a with SALL4. Finally, in vivo experiments in nude mice were implemented to assess the impact of exosome-delivered miR-15a on HCC. The exosomes from MSCs restrained HCC cell proliferative, migrating, and invasive potentials, and accelerated their apoptosis. miR-15a was expressed at low levels in HCC cells and could bind to SALL4, thus curtailing the proliferative, migrating, and invasive abilities of HCC cells. Exosomes successfully delivered miR-15a to HCC cells. Exosomal miR-15a depressed tumorigenicity and metastasis of HCC tumors in vivo. Overall, exosomal miR-15a from MSCs can downregulate SALL4 expression and thereby retard HCC development.

Inhibition of the long non-coding RNA UNC5B-AS1/miR-4455/RSPO4 axis reduces cervical cancer growth in vitro and in vivo

BACKGROUND

Long non-coding RNAs (lncRNAs) are significant regulatory factors for the initiation and development of numerous malignant tumors, including cervical cancer (CC). The expression of lncRNA unc-5 netrin receptor B antisense RNA 1 (UNC5B-AS1, also known as UASR1) is up-regulated in tissues of cervical squamous cell carcinoma and endocervical adenocarcinoma compared to in normal tissues based on the GEPIA database. In the present study, we explored the functions of UNC5B-AS1 and its underlying mechanism with respect to CC development.

METHODS

A real-time quantitative polymerase chain reaction was applied for the detection of UNC5B-AS1 expression in CC cells. Cell counting kit-8, colony formation and transwell assays, as well as western blot and flow cytometry analyses, were employed to detect the biological effects of UNC5B-AS1 knockdown on malignant phenotypes of CC cells in vitro. In addition, the combination between microRNA-4455 (miR-4455) and UNC5B-AS1 or R-spondin 4 (RSPO4) was explored by RNA immunoprecipitation, luciferase reporter and RNA pulldown assays. A tumor xenograft nude mice model was established to explore the effect of UNC5B-AS1 depletion or miR-4455 overexpression on tumor growth.

RESULTS

UNC5B-AS1 is up-regulated in CC tissues and cells. The knockdown of UNC5B-AS1 inhibits CC cell proliferation, migration and invasion and promotes CC cell apoptosis. Mechanistically, UNC5B-AS1 binds with miR-4455 to up-regulate RSPO4 expression. RSPO4 is targeted by miR-4455 and its expression is negatively regulated by miR-4455 expression. In vivo assays revealed that UNC5B-AS1 depletion or miR-4455 overexpression inhibits tumor growth by regulating RSPO4 expression.

CONCLUSIONS

Inhibition of UNC5B-AS1/miR-4455/RSPO4 reduces CC growth both in vitro and in vivo, furnishing new insights into molecular studies on UNC5B-AS1 with respect to CC development.

Reactivation of Multiple Fetal miRNAs in Lung Adenocarcinoma

MicroRNAs (miRNAs) play vital roles in the regulation of normal developmental pathways. However, cancer cells can co-opt these miRNAs, and the pathways that they regulate, to drive pro-tumourigenic phenotypes. Characterization of the miRNA transcriptomes of fetal organs is essential for identifying these oncofetal miRNAs, but it has been limited by fetal sample availability. As oncofetal miRNAs are absent from healthy adult lungs, they represent ideal targets for developing diagnostic and therapeutic strategies. We conducted small RNA sequencing of a rare collection of 25 human fetal lung (FL) samples and compared them to two independent cohorts (n = 140, n = 427), each comprised of adult non-neoplastic lung (ANL) and lung adenocarcinoma (LUAD) samples. We identified 13 oncofetal miRNAs that were expressed in FL and LUAD but not in ANL. These oncofetal miRNAs are potential biomarkers for LUAD detection (AUC = 0.963). Five of these miRNAs are derived from the imprinted C14MC miRNA cluster at the 14q32 locus, which has been associated with cancer development and abnormal fetal and placental development. Additionally, we observed the pulmonary expression of 44 previously unannotated miRNAs. The sequencing of these fetal lung samples also provides a baseline resource against which aberrant samples can be compared.

A molecular signature of well-differentiated oral squamous cell carcinoma reveals a resistance mechanism to metronomic chemotherapy and novel therapeutic candidates

Well-differentiated head and neck squamous cell carcinoma (HNSCC), accounts for approximately 10% of all HNSCCs and, while these cases are associated with good prognosis after surgery, these are resistant to chemotherapy. Here we designed a retrospective study to evaluate the effects of histological differentiation on tongue squamous cell carcinoma (TSCC) patients undergoing surgery or metronomic neoadjuvant chemotherapy. The metronomic neoadjuvant chemotherapy significantly improved overall survival of patients with poorly or moderately differentiated tumour, but not those with well-differentiated tumour. Analysis of the Cancer Genome Atlas (TCGA) showed that FAT1 mutations were significantly enriched in more differentiated HNSCC while ASPM mutations were significantly enriched among the poorly differentiated HNSCC. Interestingly, Wnt/β-catenin pathway was activated in well-differentiated HNSCC. Active β-catenin is translocated to the nucleus in the well-differentiated oral squamous cell carcinoma cell lines. Wnt inhibitor, Wnt974, were synergistic with methotrexate in killing well-differentiated oral squamous cell carcinoma (OSCC) cell lines. TCGA data analyses reveal a signature in patients with well-differentiated HNSCC who have no benefits from metronomic neoadjuvant chemotherapy, suggesting that there might be novel nosology and therapeutic candidates for improving HNSCC patient survival. Well-differentiated OSCC is synergistically killed by combination chemotherapy with Wnt inhibitor, making it promising therapeutic candidates.

Msi1 inhibits cervical cancer cell apoptosis by downregulating BAK through AKT signaling

Musashi-1 (Msi1) is an RNA binding protein that functions as a regulator in multiple carcinomas. Our previous study demonstrated that Msi1 could promote the proliferation of cervical cancer cells by targeting the cell cycle proteins P21, P27 and P53. However, the mechanisms by which Msi1 affects the survival of cervical cancer cells, such as apoptosis, are still unclear. In this study, we found that the expression of Msi1 inhibited cervical cancer cell apoptosis in vitro and in vivo. Furthermore, the expression of Msi1 downregulated the expression of PTEN, while AKT signaling was activated, which resulted in a reduction in the proapoptotic protein BAK. In addition, rescue the expression of BAK in Msi1 expressing cervical cancer cells induced the increase of apoptosis cells. These findings indicate that Msi1 regulates cervical cancer cell apoptosis by inhibiting PTEN and activating AKT signaling, which leads to the downregulation of BAK.

CircPPP1R12A promotes the progression of colon cancer through regulating CTNNB1 via sponging miR-375

Circular RNAs (circRNAs) have been identified as potential biomarkers for many cancer, including colon cancer (CC). However, the function and mechanism of circPPP1R12A in CC have not been fully elucidated. Quantitative real-time PCR was employed to assess the expression of circPPP1R12A, microRNA (miR)-375 and catenin beta-1 (CTNNB1). The proliferation, apoptosis, migration and invasion of cells were determined using colony formation assay, flow cytometry, wound healing assay and transwell assay. The protein levels of cell cyclin-related markers and CTNNB1 were detected by western blot analysis. The interaction between miR-375 and circPPP1R12A or CTNNB1 was verified by dual-luciferase reporter assay. Xenograft models were built to evaluate the effect of circPPP1R12A silencing and CTNNB1 overexpression on CC tumor growth in vivo. Our results showed that circPPP1R12A was a highly expressed circRNA in CC tissues and cells. Silenced circPPP1R12A suppressed the proliferation, promoted the apoptosis, and inhibited the migration and invasion of CC cells. MiR-375 could be sponged by circPPP1R12A, and its inhibitor could reverse the inhibition of circPPP1R12A silencing on CC progression. Furthermore, CTNNB1 was a target of miR-375, and its overexpression also abolished the suppression of miR-375 on CC progression. Moreover, circPPP1R12A indirectly regulated CTNNB1 expression by sponging miR-375. Importantly, circPPP1R12A knockdown reduced the tumor growth of CC in vivo, and this effect also could be reversed by overexpressing CTNNB1. Our study proposed that circPPP1R12A might play an oncogenic role in CC, which could act as a potential therapeutic target for CC.

Up-Regulation of SALL4 Is Associated With Survival and Progression via Putative WNT Pathway in Gastric Cancer

SALL4, a transcriptional factor involved in embryonic stem cell self-renewal and pluripotency, is overexpressed in gastric cancer (GC). However, the association of SALL4 with the survival of GC patients is not well-understood, and the role of SALL4 in cancer progression is still unknown. In the present study, a total of 1,815 GC patients who underwent radical resection at Peking Cancer Hospital were included consecutively from 2015 to 2018, confirming the prognostic value of SALL4 and validating by data from TCGA and GEO. The protein and mRNA expression levels of SALL4 were evaluated by immunohistochemistry and qPCR, respectively. Besides, GSEA and WGCNA were applied to explore the SALL4-related cancer-promoting signaling pathways and gene modules. Our results showed that overexpression of SALL4 was observed in 16.7% of GC patients. SALL4 positivity was associated with male, older age, mixed-type histology, late stages, lymphatic metastasis, vascular invasion, non-cardia location, high AFP level, and no EBV infection background. SALL4 could be served as a marker for prognostic prediction in GC, and SALL4-positive GC was significantly associated with shortened survival. Further, the bioinformatic analysis indicated that the Wnt/β-catenin signaling pathway was activated in SALL4-high cases compared with SALL4-low cases. Expression of SALL4 was also positively correlated with the expression of multiple co-expressed genes, such as TRIB3, which plays an important role in activating the Wnt/β-catenin pathway. Our findings indicate that SALL4 is associated with clinicopathological features related to cancer progression in GC and its function in the Wnt/β-catenin pathway.

HOXB4 inhibits the proliferation and tumorigenesis of cervical cancer cells by downregulating the activity of Wnt/β-catenin signaling pathway

Homeobox B4 (HOXB4), which belongs to the homeobox (HOX) family, possesses transcription factor activity and has a crucial role in stem cell self-renewal and tumorigenesis. However, its biological function and exact mechanism in cervical cancer remain unknown. Here, we found that HOXB4 was markedly downregulated in cervical cancer. We demonstrated that HOXB4 obviously suppressed cervical cancer cell proliferation and tumorigenic potential in nude mice. Additionally, HOXB4-induced cell cycle arrest at the transition from the G0/G1 phase to the S phase. Conversely, loss of HOXB4 promoted cervical cancer cell growth both in vitro and in vivo. Bioinformatics analyses and mechanistic studies revealed that HOXB4 inhibited the activity of the Wnt/β-catenin signaling pathway by direct transcriptional repression of β-catenin. Furthermore, β-catenin re-expression rescued HOXB4-induced cervical cancer cell defects. Taken together, these findings suggested that HOXB4 directly transcriptional repressed β-catenin and subsequently inactivated the Wnt/β-catenin signaling pathway, leading to significant inhibition of cervical cancer cell growth and tumor formation.

Argonaute 3 (AGO3) promotes malignancy potential of cervical cancer via regulation of Wnt/β-catenin signaling pathway

We aimed to investigate the biological roles of Argonaute 3 (AGO3) in cervical cancer. RNA profiles containing 306 cervical cancer tissues and 13 normal samples revealed that AGO3 was significantly up-regulated in cervical cancer, and the expression of AGO3 was negatively associated with the outcome of cervical cancer patients. Cell proliferation and transwell assays showed that the depletion of AGO3 markedly inhibited cervical cancer cell growth and mobility. Importantly, we detected that knockdown of AGO3 exerted suppressive effect on cellular behaviors via inactivating Wnt/β-catenin signaling pathway. Collectively, we conclude that AGO3 is a novel tumor promoter in cervical cancer and has a potential to be a drug target and prognostic predictor of cervical cancer patients.

WAPL induces cervical intraepithelial neoplasia modulated with estrogen signaling without HPV E6/E7

Since cervical cancer still afflicts women around the world, it is necessary to understand the underlying mechanism of cervical cancer development. Infection with HPV is essential for the development of cervical intraepithelial neoplasia (CIN). In addition, estrogen receptor signaling is implicated in the development of cervical cancer. Previously, we have isolated human wings apart-like (WAPL), which is expected to cause chromosomal instability in the process of HPV-infected precancerous lesions to cervical cancer. However, the role of WAPL in the development of CIN is still unknown. In this study, in order to elucidate the role of WAPL in the early lesion, we established WAPL overexpressing mice (WAPL Tg mice) and HPV E6/E7 knock-in (KI) mice. WAPL Tg mice developed CIN lesion without HPV E6/E7. Interestingly, in WAPL Tg mice estrogen receptor 1 (ESR1) showed reduction as compared with the wild type, but cell growth factors MYC and Cyclin D1 controlled by ESR1 expressed at high levels. These results suggested that WAPL facilitates sensitivity of ESR1 mediated by some kind of molecule, and as a result, affects the expression of MYC and Cyclin D1 in cervical cancer cells. To detect such molecules, we performed microarray analysis of the uterine cervix in WAPL Tg mice, and focused MACROD1, a co-activator of ESR1. MACROD1 expression was increased in WAPL Tg mice compared with the wild type. In addition, knockdown of WAPL induced the downregulation of MACROD1, MYC, and Cyclin D1 but not ESR1 expression. Furthermore, ESR1 sensitivity assay showed lower activity in WAPL or MACROD1 downregulated cells than control cells. These data suggested that WAPL increases ESR1 sensitivity by activating MACROD1, and induces the expression of MYC and Cyclin D1. Therefore, we concluded that WAPL not only induces chromosomal instability in cervical cancer tumorigenesis, but also plays a key role in activating estrogen receptor signaling in early tumorigenesis.

Tripartite Motif-Containing 44 is Involved in the Tumorigenesis of Laryngeal Squamous Cell Carcinoma, and its Expression is Downregulated by Nuciferine

Tripartite motif-containing 44 (TRIM44) was reported to be involved in the tumorigenesis of several tumors, but its function in laryngeal squamous cell carcinoma has not been investigated yet. In the present study, we aimed to elucidate the function of TRIM44 in laryngeal squamous cell carcinoma, and identify the compounds which could inhibit TRIM44 expression. Our results showed that TRIM44 was upregulated in tumor tissues and cell lines of laryngeal squamous cell carcinoma. Knockdown of TRIM44 significantly inhibited cell growth of laryngeal squamous cell carcinoma by suppressing TLR4, phosphorylated AKT and phosphorylated NF-κB p65 expression in vitro. Moreover, TRIM44 knockdown inhibited tumor growth in nude mice, which further suggested that TRIM44 exerted oncogenic activity in laryngeal squamous cell carcinoma. Interestingly, it was found that nuciferine significantly inhibited the mRNA levels of TRIM44 after screening a small natural compound library. Our further studies showed nuciferine markedly downregulated the protein levels of TRIM44 and its substrate TLR4 in a concentration-dependent manner in laryngeal squamous cell carcinoma cells. Moreover, the activation of downstream kinases of TLR4 such as AKT signaling pathway was also inhibited by nuciferine. Additionally, nuciferine markedly inhibited cell survival of laryngeal squamous cell carcinoma in a concentration-dependent manner. In contrast, TRIM44 overexpression significantly reduced the cytotoxicity of nuciferine in laryngeal squamous cell carcinoma cells. In conclusion, this study indicated that inhibiting TRIM44 would be a useful strategy for the treatment of laryngeal squamous cell carcinoma, and nuciferine could be a potential chemical applicated in the therapy of laryngeal squamous cell carcinoma.

Effect of SALL4 on the Proliferation, Invasion and Apoptosis of Breast Cancer Cells

Objective:

We aimed to identify the expression of Sal-like 4 (SALL4) in breast cancer tissues and to explore the role of this gene in the carcinogenesis of breast cancer cells.

Methods:

A total of 62 paired breast cancer and noncancerous tissue samples were obtained from patients with breast cancer. SALL4 expression patterns and their association with clinicopathological characteristics were investigated by qRT-PCR, western blotting, and immunochemistry in breast cancer tissues. After the knockdown of SALL4 by short hairpin RNAs (shRNAs), the proliferative, invasive, and apoptotic abilities of MDA-MB-435 and MDA-MB-468 cells (breast cancer cell lines) were measured by colony formation and CCK-8 assays, wound healing and transwell assays, and flow cytometry, respectively.

Results:

SALL4 expression was higher in breast cancer tissues than that in the paired noncancerous tissues, and increased SALL4 expression in tumor tissues was closely related to tumor size and lymphatic metastasis. Furthermore, functional experiments revealed that SALL4 knockdown inhibited the cell proliferation, induced cell cycle arrest in G0/G1phase and apoptosis, and decreased the ability of migration and invasion in breast cancer cells. Additionally, our study first demonstrated that SALL4 played a critical role in modulating the tumorigenicity of breast cancer cells via the WNT/β-catenin signaling pathway.

Conclusions:

Our results suggest that the expression of SALL4 is upregulated in breast cancer, and this upregulation is involved in the regulation of cell growth, invasion, and apoptosis. Hence, SALL4 may be a promising target for diagnosis and therapy in patients with breast cancer.

Knockdown of SALL4 inhibits the proliferation, migration, and invasion of human lung cancer cells in vivo and in vitro

Background

This study aimed to investigate the SALL4 expression in lung cancer, determine if SALL4 regulates the biological functions of lung cancer cells at the cellular level, and clarify the possible mechanisms involved.

Methods

Immunohistochemistry was used to detect the SALL4 expression messenger RNA (mRNA) in 62 cases of lung cancer tissue microarray. The correlation of SALL4 with the clinical pathological parameters and overall life cycle of patients and the impact of disease-free life cycle was analyzed. Reverse transcription-polymerase chain reaction (RT-PCR) and western blotting were used to detect the SALL4 expression in lung cancer cell lines and nude mouse models. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay, colony-forming assay, and flow cytometry were used to detect the effects of interference with SALL4 expression on lung cancer cell proliferation and transplant tumor models; the effect of interference with SALL4 expression on the growth of transplanted tumors in vivo was also examined.

Results

SALL4 was highly expressed in lung cancer tissues and cell lines and was closely related to the patient's TNM stage and lymph node metastasis. Compared to patients with a high SALL4 expression, those with a lower SALL4 expression had a longer overall and disease-free survival. The expression of SALL4 is an independent risk factor for the prognosis of lung cancer patients. Interference with SALL4 expression can significantly inhibit cell proliferation and clonal formation. Interfering with the expression of SALL4 can arrest the cells in the G0/G1 phase by inhibiting the expression of the cell cycle-related proteins, cyclin B, cyclin E, and cyclin D1. Furthermore, wound-healing and Transwell assays showed that interference with SALL4 expression could significantly inhibit the migration and invasion of lung cancer cells, while experiments in nude mice showed that interference with SALL4 expression could significantly inhibit the size and weight of transplanted tumors.

Conclusions

SALL4 was highly expressed in lung cancer cell lines. Interference with the expression of SALL4 can effectively inhibit the proliferation, migration and invasion of lung cancer cells, promote cell cycle arrest, and play the function of tumor suppressor genes. SALL4 may be a new target for the diagnosis and treatment of lung cancer.

Spalt-like transcription factor 4 expression in oral epithelial dysplasia and oral squamous cell carcinoma: An immunohistochemical appraisal

BACKGROUND:

Spalt-like transcription factor 4 (SALL4) is a stem cell marker that plays a critical role in maintaining the pluripotency and self-renewal of embryonic and hematopoietic stem cells. Only a few studies have been done to apprehend the expression of SALL4 in the potentially malignant oral lesion (leukoplakia with dysplasia) and oral squamous cell carcinoma (OSCC).

AIM:

The aim of this study is to evaluate the expression of SALL4 in leukoplakia with dysplasia and OSCC and to correlate the expression of the marker (SALL4) with the various clinicopathological parameters and patient outcome.

MATERIALS AND METHODS:

Immunohistochemistry for SALL4 protein was performed on 140 cases: those histopathologically confirmed cases of leukoplakia with dysplasia (n = 30) and OSCC (n = 110). Ten cases of nonepithelial neoplasm (fibroepithelial hyperplasia and excised tissue surrounding impacted third molars) were taken as control. Statistical analyses were applied to evaluate correlations between SALL4 overexpression and clinicopathological features of leukoplakia and OSCC. Survival rates were analyzed using Kaplan–Meier method.

RESULTS:

SALL4 positivity was observed to be higher (P = 0.001) in the tumor cells of OSCC with Immuno Reactive Score (IRS) ranging from 0 to 9. Poorly differentiated squamous cell carcinoma (SCC) had paramount higher expression with a median IRS of 6. Similar IRS and above (IRS, 6–9) was observed in Stage I (five cases), which recurred and well-differentiated cases with metastasis (four cases) while in leukoplakia with dysplasia the SALL4 expression was weak with a range of 2–4.

CONCLUSIONS:

SALL4 being one of the cancer stem cell molecules plays an important role in the progression of oral cancer, which was evident in this study. This could also account for aggressive clinical behavior. Follow-up of these patients would relate this molecule could be responsible for cancer relapse. Patients diagnosed to have oral epithelial dysplasia had a low expression of SALL4, are under follow-up, although seven cases did transform to SCC. Thus, we conclude, SALL4 may be of prognostic relevance, but in oral epithelial dysplasia, it requires further investigations.

Wnt Signaling in Gynecologic Malignancies

Gynecologic malignancies, including ovarian cancer, endometrial cancer, and cervical cancer, affect hundreds of thousands of women worldwide every year. Wnt signaling, specifically Wnt/β-catenin signaling, has been found to play an essential role in many oncogenic processes in gynecologic malignancies, including tumorigenesis, metastasis, recurrence, and chemotherapy resistance. As such, the Wnt/β-catenin signaling pathway has the potential to be a target for effective treatment, improving patient outcomes. In this review, we discuss the evidence supporting the importance of the Wnt signaling pathways in the development, progression, and treatment of gynecologic malignancies.

VHL mutation-mediated SALL4 overexpression promotes tumorigenesis and vascularization of clear cell renal cell carcinoma via Akt/GSK-3β signaling

Background

Although ongoing development of therapeutic strategies contributes to the improvements in clinical management, clear cell renal cell carcinoma (ccRCC) deaths originate mainly from radiochemoresistant and metastatic disease. Transcription factor SALL4 has been implicated in tumorigenesis and metastasis of multiple cancers. However, it is not known whether SALL4 is involved in the pathogenesis of ccRCC.

Methods

Analyses of clinical specimen and publicly available datasets were performed to determine the expression level and clinical significance of SALL4 in ccRCC. The influence of SALL4 expression on ccRCC tumor growth, metastasis and vascularity was evaluated through a series of in vitro and in vivo experiments. Western blotting, immunofluorescence staining and integrative database analysis were carried out to investigate the underlying mechanism for SALL4-mediated oncogenic activities in ccRCC.

Results

SALL4 expression was increased in ccRCC and positively correlated with tumor progression and poor prognosis. SALL4 could promote ccRCC cell proliferation, colony formation, cell cycle progression, migration, invasion and tumorigenicity and inhibit cell senescence. Further investigation revealed a widespread association of SALL4 with individual gene transcription and the involvement of SALL4 in endothelium development and vasculogenesis. In the context of ccRCC, SALL4 promoted tumor vascularization by recruiting endothelial cells. In addition, we found that SALL4 could exert its tumor-promoting effect via modulating Akt/GSK-3β axis and VEGFA expression. VHL mutation and DNA hypomethylation may be involved in the upregulation of SALL4 in ccRCC.

Conclusions

Overall, our results provide evidence that upregulated SALL4 can function as a crucial regulator of tumor pathogenesis and progression in ccRCC, thus offering potential therapeutic strategies for future treatment.

Spalt-Like Protein 4 (SALL4) Promotes Angiogenesis by Activating Vascular Endothelial Growth Factor A (VEGFA) Signaling

Background

Spalt-like protein 4 (SALL4) is a nuclear transcription factor central to early embryonic development, especially for regulating pluripotency of embryonic stem cells (ESCs) and sustaining ESCs self-renewal. Aberrant re-expression of SALL4 in adult tissues is involved in tumorigenesis and cancer progression. However, the role of SALL4 in angiogenesis remains elusive. Here, we determined the potential action of SALL4 on proliferation, migration, and tube formation of endothelial cells.

Material/Methods

HUVECs were infected with lentiviral particles expressing shRNA against SALL4. QRT-PCR and immunoblotting analysis were carried out to evaluate knockdown efficiency at mRNA and protein levels. Cell proliferation was measured by CCK-8 assay and flow cytometry was conducted to analyze cell cycle distribution. Wound-healing and Transwell migration assays were performed to evaluate cell motility. In addition, we determined the role of SALL4 on angiogenesis by tube formation assay, and Western blot analysis was used to assess the effect of SALL4 downregulation on VEGFA expression.

Results

We found that SALL4 downregulation resulted in decreased proliferation. Cell cycle analysis revealed that SALL4 knockdown impeded cell cycle progression and induced cell cycle arrest at G1 phase. We also found that silencing of SALL4 decreased the capacity of wound healing and cell migration in HUVECs. Furthermore, tube formation assay showed that loss of SALL4 inhibited HUVECs angiogenesis. We also observed that SALL4 knockdown reduced the level of VEGFA in HUVECs.

Conclusions

In conclusion, these results support that by promoting proliferation, cell cycle progression, migration, and tube formation, SALL4 is involved in the process of angiogenesis through modulating VEGFA expression.

THG-1 suppresses SALL4 degradation to induce stemness genes and tumorsphere formation through antagonizing NRBP1 in squamous cell carcinoma cells

Knockdown of THG-1 in TE13 esophageal squamous cell carcinoma (ESCC) cells is known to suppress tumorsphere growth. THG-1 was identified as an NRBP1 binding protein, and NRBP1 was reported to downregulate an stemness-related transcriptional factor SALL4, so we decided to examine the possibility that tumorigenic function of THG-1 is achieved by the competition to the tumor-suppressive function of NRBP1. SALL4 was decreased in THG-1 deficient TE13 cells with reduced tumorsphere formation, while exogenous SALL4 expression in THG-1 deficient TE13 cells recovered expression of stemness genes (NANOG and OCT4) and partially, but significantly, recovered tumorsphere formation ability. Additionally, we found that NRBP1 induced ubiquitination of SALL4, and THG-1 interrupted the ubiquitination of SALL4 by antagonizing NRBP1 binding to SALL4. These results suggest that THG-1 promotes tumorsphere growth of ESCC cells by the stabilization of SALL4 protein and induction of the target stemness genes through competitive binding to NRBP1.

SALL4 promotes the tumorigenicity of cervical cancer cells through activation of the Wnt/β-catenin pathway via CTNNB1

SALL4 is overexpressed in many cancers and is found to be involved in tumorigenesis and tumor progression. However, the function of SALL4 in cervical cancer remains unknown. Here, we showed that the expression of SALL4 was gradually increased from normal cervical tissue to high-grade squamous intraepithelial lesions and then to squamous cervical carcinoma. SALL4 was upregulated or downregulated in cervical cancer cells by stably transfecting a SALL4-expressing plasmid or a shRNA plasmid targeting SALL4, respectively. In vitro, cell growth curves and MTT (3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide) assays showed that SALL4 promoted the cell proliferation of cervical cancer cells. In vivo, xenograft experiments verified that SALL4 enhanced the tumor formation of cervical cancer cells in female BALB/c Nude mice. Cell cycle analysis by fluorescence-activated cell sorting found that SALL4 accelerates cell cycle transition from the G0 /G1 phase to the S phase. TOP/FOP-Flash reporter assay revealed that SALL4 significantly upregulates the activity of Wnt/β-catenin pathway. Western blotting showed that the expression levels of β-catenin and important downstream genes, including c-Myc and cyclin D1, were increased by SALL4 in cervical cancer cells. Furthermore, dual-luciferase reporter and chromatin immunoprecipitation assays confirmed that SALL4 transcriptionally activated CTNNB1 by physically interacting with its promoters. Taken together, The results of this study demonstrated that SALL4 may promote cell proliferation and tumor formation of cervical cancer cells by upregulating the activity of the Wnt/β-catenin signaling pathway by directly binding to the CTNNB1 promoter and trans-activating CTNNB1.