Role of Hedgehog Signaling in Breast Cancer: Pathogenesis and Therapeutics. Cells. 2019;8. [PMID: 31027259 DOI: 10.3390/cells8040375]

CD44/PD-L1-mediated networks in drug resistance and immune evasion of breast cancer stem cells: Promising targets of natural compounds

Cancer stem cells (CSCs) significantly interfere with immunotherapy, leading to challenges such as low response rates and acquired resistance. PD-L1 expression is associated with the CSC population's overexpression of CD44. Mounting evidence suggests that the breast cancer stem cell (BCSC) marker CD44 and the immune checkpoint PD-L1 contribute to treatment failure through their networks. Natural compounds can overcome therapy resistance in breast cancer by targeting mechanisms underlying resistance in BCSCs. This review provides an updated insight into the CD44 and PD-L1 networks of BCSCs in mediating metastasis and immune evasion. The review critically examines existing literature, providing a comprehensive understanding of the topic and emphasizing the impact of natural flavones on the signaling pathways of BCSCs. Additionally, the review discusses the potential of natural compounds in targeting CD44 and PD-L1 in breast cancer (BC). Natural compounds consistently show potential in targeting regulatory mechanisms of BCSCs, inducing loss of stemness, and promoting differentiation. They offer a promising approach for developing alternative therapeutic strategies to manage breast cancer.

Alterations of ceramide synthesis induce PD-L1 internalization and signaling to regulate tumor metastasis and immunotherapy response

Programmed death ligand 1, PD-L1 (CD274), facilitates immune evasion and exerts pro-survival functions in cancer cells. Here, we report a mechanism whereby internalization of PD-L1 in response to alterations of bioactive lipid/ceramide metabolism by ceramide synthase 4 (CerS4) induces sonic hedgehog (Shh) and transforming growth factor β receptor signaling to enhance tumor metastasis in triple-negative breast cancers (TNBCs), exhibiting immunotherapy resistance. Mechanistically, data showed that internalized PD-L1 interacts with an RNA-binding protein, caprin-1, to stabilize Shh/TGFBR1/Wnt mRNAs to induce β-catenin signaling and TNBC growth/metastasis, consistent with increased infiltration of FoxP3+ regulatory T cells and resistance to immunotherapy. While mammary tumors developed in MMTV-PyMT/CerS4-/- were highly metastatic, targeting the Shh/PD-L1 axis using sonidegib and anti-PD-L1 antibody vastly decreased tumor growth and metastasis, consistent with the inhibition of PD-L1 internalization and Shh/Wnt signaling, restoring anti-tumor immune response. These data, validated in clinical samples and databases, provide a mechanism-based therapeutic strategy to improve immunotherapy responses in metastatic TNBCs.

Breast cancer drug resistance: Decoding the roles of Hippo pathway crosstalk

The most significant factors that lead to cancer-related death in breast cancer (BC) patients include drug resistance, migration, invasion, and metastasis. Several signaling pathways are involved in the development of BC. The different types of BC are initially sensitive to chemotherapy, and drug resistance can occur through multiple molecular mechanisms. Regardless of developing targeted Therapy, due to the heterogenic nature and complexity of drug resistance, it is a major clinical challenge with the low survival rate in BC patients. The deregulation of several signaling pathways, particularly the Hippo pathway (HP), is one of the most recent findings about the molecular mechanisms of drug resistance in BC, which are summarized in this review. Given that HP is one of the recent cancer research hotspots, this review focuses on its implication in BC drug resistance. Unraveling the different molecular basis of HP through its crosstalk with other signaling pathways, and determining the effectiveness of HP inhibitors can provide new insights into possible therapeutic strategies for overcoming chemoresistance in BC.

Implicating clinical utility of altered expression of PTCH1 & SMO in oral squamous cell carcinoma

INTRODUCTION

Oral cancer poses a significant burden on public health in India, with higher incidence and mortality rates. Despite advancements in treatment modalities, prognosis remains poor due to factors such as localized recurrence and lymph node metastasis, potentially influenced by cancer stem cells. Among signaling pathways implicated in CSC regulation, the Hedgehog pathway plays a crucial role in oral squamous cell carcinoma (OSCC).

MATERIAL & METHODS

97 OSCC patients' tissue samples were collected and subjected to RNA isolation, cDNA synthesis and quantitative real-time PCR to analyze PTCH1 and SMO expression. Protein expression was assessed through immunohistochemistry. Clinicopathological parameters were correlated with gene and protein expression. Statistical analysis included Pearson chi-square tests, co-relation co-efficient tests, Kaplan-Meier survival analysis and ROC curve analysis.

RESULTS

PTCH1 expression correlated with lymphatic permeation (p = 0.002) and tumor stage (p = 0.002), while SMO expression correlated with lymph node status (p = 0.034) and tumor stage (p = 0.021). PTCH1 gene expression correlated with lymph node status (p = 0.024). High PTCH1 gene expression was associated with shorter survival in tongue cancer patients. ROC curve analysis indicated diagnostic potential for PTCH1 and SMO gene and cytoplasmic SMO expression in distinguishing malignant tissues from adjacent normal tissues.

CONCLUSION

PTCH1 and SMO play a crucial role in oral cancer progression, correlating with tumor stages and metastatic potential. Despite not directly influencing overall survival, PTCH1 expression at specific anatomical sites hints at its prognostic implications. PTCH1 and SMO exhibit diagnostic potential, suggesting their utility as molecular markers in oral cancer management and therapeutic strategies.

Construction of a prognostic score model for breast cancer based on multi-omics analysis of study on bone metastasis

Background

Breast cancer (BRCA) is the most common type of cancer and the second leading cause of cancer-related death in women all over the world. Metastasis to bone is an indicator of poor prognosis in BRCA patients. This study aimed to develop a prognostic score model for predicting bone metastasis in patients with BRCA.

Methods

BRCA-related RNA sequencing datasets and corresponding clinical information were downloaded from the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA). Differentially expressed genes (DEGs) were screened using Limma package of R software. A risk score based predictive model was constructed based on the key genes identified through univariate Cox regression and the least absolute shrinkage and selection operator (LASSO) Cox regression. The gene expression profiles in BRCA patients were analyzed by gene set variation analysis (GSVA) and gene set enrichment analysis (GSEA). Random survival forest (RSF) analysis of BRCA patients with bone metastasis was conducted to identify the key DEGs.

Results

Based on DEG analysis, a total of 677 genes were identified as genes related to bone metastasis in BRCA. By univariate Cox regression and LASSO regression, 28 DEGs were identified as signature genes to develop the prognostic model. A risk score for each patient was created by incorporating the expression values of each specific gene and weighting them with the corresponding estimated regression coefficients. Patients were divided into a low-risk and a high-risk group based on the median risk score. Overall survival (OS) was significantly lower in the high-risk group. The receiver operating characteristic (ROC) curve and multi-omics analysis indicated that the model had high training/testing accuracy and a good clinical predictive value. We used extra data from GEO database to verify the robustness of the prognostic model, and the lower OS in high-risk group and area under the curve (AUC) value indicated the model had strong predictive efficacy for prognosis of BRCA.

Conclusions

A prognostic prediction model was constructed based on 28 key DEGs identified through multi-omics analysis of studies on bone metastasis. The model may provide a promising method for distinguishing the high-risk BRCA patients and help on decision making in addition to prognosis prediction for BRCA patients.

SALL4 upregulates brain-derived neurotrophic factor to mediate Hedgehog signaling to inhibit carboplatin sensitivity in colon adenocarcinoma

Aim: This study aimed to investigate the role of brain-derived neurotrophic factor (BDNF) in colon adenocarcinoma, specifically its impact on sensitivity to carboplatin. Methods: mRNA and clinical information of colon adenocarcinoma samples were obtained from TCGA database. Differential expression analysis, transcription factor prediction, gene set enrichment analysis were performed in silico. qRT-PCR, western blot, CCK-8 and CHIP assay were employed. Results: BDNF demonstrated high expression in colon adenocarcinoma. Silencing of BDNF enhanced carboplatin sensitivity, while exerting opposite effects on epithelial-mesenchymal transition (EMT). BDNF was enriched in Hedgehog (HH) signaling pathway. SALL4 was identified as an upstream regulator of BDNF. Upregulation of BDNF by SALL4 promoted EMT and inhibited carboplatin sensitivity. Conclusion: SALL4 promoted BDNF expression to facilitate the aggressive phenotypes of colon adenocarcinoma.

Beyond cyclopamine: Targeting Hedgehog signaling for cancer intervention

Hedgehog (Hh) signaling plays a significant role in embryogenesis and several physiological processes, such as wound healing and organ homeostasis. In a pathological setting, it is associated with oncogenesis and is responsible for disease progression and poor clinical outcomes. Hedgehog signaling mediates downstream actions via Glioma Associated Oncogene Homolog (GLI) transcription factors. Inhibiting Hh signaling is an important oncological strategy in which inhibitors of the ligands SMO or GLI have been looked at. This review briefly narrates the Hh ligands, signal transduction, the target genes involved and comprehensively describes the numerous inhibitors that have been evaluated for use in various neoplastic settings.

Molecular pathways and therapeutic targets linked to triple-negative breast cancer (TNBC)

Cancer is a group of diseases characterized by uncontrolled cellular growth, abnormal morphology, and altered proliferation. Cancerous cells lose their ability to act as anchors, allowing them to spread throughout the body and infiltrate nearby cells, tissues, and organs. If these cells are not identified and treated promptly, they will likely spread. Around 70% of female breast cancers are caused by a mutation in the BRCA gene, specifically BRCA1. The absence of progesterone, oestrogen and HER2 receptors (human epidermal growth factor) distinguishes the TNBC subtype of breast cancer. There were approximately 6,85,000 deaths worldwide and 2.3 million new breast cancer cases in women in 2020. Breast cancer is the most common cancer globally, affecting 7.8 million people at the end of 2020. Compared to other cancer types, breast cancer causes more women to lose disability-adjusted life years (DALYs). Worldwide, women can develop breast cancer at any age after puberty, but rates increase with age. The maintenance of mammary stem cell stemness is disrupted in TNBC, governed by signalling cascades controlling healthy mammary gland growth and development. Interpreting these essential cascades may facilitate an in-depth understanding of TNBC cancer and the search for an appropriate therapeutic target. Its treatment remains challenging because it lacks specific receptors, which renders hormone therapy and medications ineffective. In addition to radiotherapy, numerous recognized chemotherapeutic medicines are available as inhibitors of signalling pathways, while others are currently undergoing clinical trials. This article summarizes the vital druggable targets, therapeutic approaches, and strategies associated with TNBC.

Epigenetic Effects of Resveratrol on Oncogenic Signaling in Breast Cancer

The crosstalk between oncogenic signaling pathways plays a crucial role in driving cancer development. We previously demonstrated that dietary polyphenols, specifically resveratrol (RSV) and other stilbenoids, epigenetically target oncogenes for silencing via DNA hypermethylation in breast cancer. In the present study, we identify signal transduction regulators among RSV-hypermethylated targets and investigate the functional role of RSV-mediated DNA hypermethylation in the regulation of Hedgehog and Wnt signaling. Non-invasive ER-positive MCF-7 and highly invasive triple-negative MCF10CA1a human breast cancer cell lines were used as experimental models. Upon 9-day exposure to 15 µM RSV, pyrosequencing and qRT-PCR were performed to assess DNA methylation and expression of GLI2 and WNT4, which are upstream regulators of the Hedgehog and Wnt pathways, respectively. Our results showed that RSV led to a DNA methylation increase within GLI2 and WNT4 enhancers, which was accompanied by decreases in gene expression. Consistently, we observed the downregulation of genes downstream of the Hedgehog and Wnt signaling, including common targets shared by both pathways, CCND1 and CYR61. Further analysis using chromatin immunoprecipitation identified increased H3K27 trimethylation and decreased H3K9 and H3K27 acetylation, along with abolishing OCT1 transcription factor binding. Those changes indicate a transcriptionally silent chromatin state at GLI2 and WNT4 enhancers. The inhibition of the Wnt signal transduction was confirmed using a phospho-antibody array that demonstrated suppression of positive and stimulation of negative Wnt regulators. In conclusion, our results provide scientific evidence for dietary polyphenols as epigenetics-modulating agents that act to re-methylate and silence oncogenes, reducing the oncogenic signal transduction. Targeting such an action could be an effective strategy in breast cancer prevention and/or adjuvant therapy.

Importance of targeting various cell signaling pathways in solid cancers

Most adult human cancers are solid tumors prevailing in vital organs and lead to mortality all over the globe. Genetic and epigenetic alterations in cancer genes or genes of associated signaling pathways impart the most common characteristic of malignancy, that is, uncontrolled proliferation. Unless the mechanism of action of these cells signaling pathways (involved in cell proliferation, apoptosis, metastasis, and the maintenance of the stemness of cancer stem cells and cancer microenvironment) and their physiologic alteration are extensively studied, it is challenging to understand tumorigenesis as well as develop new treatments and precision medicines. Targeted therapy is one of the most promising strategies for treating various cancers. However, cancer is an evolving disease, and most patients develop resistance to these drugs by acquired mutations or mediation of microenvironmental factors or due to tumor heterogeneity. Researchers are striving to develop novel therapeutic options like combinatorial approaches targeting multiple responsible pathways effectively. Thus, in-depth knowledge of cell signaling and its components remains a critical topic of cancer research. This chapter summarized various extensively studied pathways in solid cancer and how they are targeted for therapeutic strategies.

Combinational therapy with Myc decoy oligodeoxynucleotides encapsulated in nanocarrier and X-irradiation on breast cancer cells

The Myc gene is the essential oncogene in triple-negative breast cancer (TNBC). This study investigates the synergistic effects of combining Myc decoy oligodeoxynucleotides-encapsulated niosomes-selenium hybrid nanocarriers with X-irradiation exposure on the MDA-MB-468 cell line. Decoy and scramble ODNs for Myc transcription factor were designed and synthesized based on promoter sequences of the Bcl2 gene. The nanocarriers were synthesized by loading Myc ODNs and selenium into chitosan (Chi-Se-DEC), which was then encapsulated in niosome-nanocarriers (NISM@Chi-Se-DEC). FT-IR, DLS, FESEM, and hemolysis tests were applied to confirm its characterization and physicochemical properties. Moreover, cellular uptake, cellular toxicity, apoptosis, cell cycle, and scratch repair assays were performed to evaluate its anticancer effects on cancer cells. All anticancer assessments were repeated under X-ray irradiation conditions (fractionated 2Gy). Physicochemical characteristics of niosomes containing SeNPs and ODNs showed that it is synthesized appropriately. It revealed that the anticancer effect of NISM@Chi-Se-DEC can be significantly improved in combination with X-ray irradiation treatment. It can be concluded that NISM@Chi-Se-DEC nanocarriers have the potential as a therapeutic agent for cancer treatment, particularly in combination with radiation therapy and in-vivo experiments are necessary to confirm the efficacy of this nano-drug.

A review of biological targets and therapeutic approaches in the management of triple-negative breast cancer

BACKGROUND

Triple-negative breast cancer (TNBC) is a heterogeneous, aggressive phenotype of breast cancer with associated chemoresistance. The development of chemo- or radioresistance could be attributed to diverse tumor microenvironments, overexpression of membrane proteins (transporters), epigenetic changes, and alteration of the cell signaling pathways/genes associated with the development of cancer stem cells (CSCs).

AIM OF REVIEW

Due to the diverse and heterogeneous nature of TNBC, therapeutic response to the existing modalities offers limited scope and thus results in reccurance after therapy. To establish landmark therapeutic efficacy, a number of novel therapeutic modalities have been proposed. In addition, reversal of the resistance that developed during treatment may be altered by employing appropriate therapeutic modalities. This review aims to discuss the plethora of investigations carried out, which will help readers understand and make an appropriate choice of therapy directed toward complete elimination of TNBC.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This manuscript addresses the major contributory factors from the tumor microenvironment that are responsible for the development of chemoresistance and poor prognosis. The associated cellular events and molecular mechanism-based therapeutic interventions have been explained in detail. Inhibition of ABC transporters, cell signaling pathways associated with CSCs, and epigenetic modification offers promising results in this regard. TNBC progression, invasion, metastasis and recurrence can also be inhibited by blocking multiple cell signaling pathways, targeting specific receptors/epigenetic targets, disrupting bioenergetics and generating reactive oxygen species (ROS).

A clinicopathological exploration of Hedgehog signaling: implications in oral carcinogenesis

INTRODUCTION

Hedgehog Signaling, a basic cancer stem cell pathway, plays a major role during the embryonic development, is known to play a quiescent role in adults. However, aberrant activation of Hedgehog signaling in adults is known to play a role in cancer development. Hence, the aim of the study was to identify the role of Hedgehog signaling pathway in the Oral cancers.

MATERIALS AND METHODS

The expression of Hedgehog signaling pathway was evaluated in 124 patients through the quantitative real-time PCR. The association between the gene expression and clinico-pathological parameters were analyzed using the Pearson chi-square test and survival analysis was carried out using Kaplan-Meier analysis.

RESULTS

SHH and GLI1 was found to be significantly associated with the Lymph Node Status and SUFU was significantly associated with the Age. SMO and SUFU were found to have a worse prognosis in oral cancer patients. According to our findings, IHH plays a critical role in the activation of the HH signaling pathway in oral cancer.

CONCLUSION

These findings back up the use of the Hedgehog signaling pathway as a biomarker for early disease prediction in oral cancer, as well as its role in tumor aggressiveness and invasiveness.

The immunoreactivity of GLI1 and VEGFA is a potential prognostic factor in kidney renal clear cell carcinoma

Kidney renal clear cell carcinoma (KIRC) is the most common type of kidney cancer and its pathogenesis is strongly associated with VHL-HIF-VEGF signaling. SHH ligand is the upstream SHH pathway regulator, while GLI1 is its major effector that stimulates as a transcription factor, i.a. expression of VEGFA gene. The aim of present study was to assess the prognostic significance of SHH, GLI1 and VEGFA immunoreactivity in KIRC tissues. The analysis included paired tumor and normal samples from 34 patients with KIRC. The immunoreactivity of SHH, GLI1 and VEGFA proteins was determined by immunohistochemical (IHC) renal tissues staining. The IHC staining results were assessed using the immunoreactive score (IRS) method which takes into account the number of cells showing a positive reaction and the intensity of the reaction. Increased GLI1 protein immunoreactivity was observed in KIRC tissues, especially in early-stage tumors, according to the TNM classification. Elevated expression of the VEGFA protein was noted primarily in high-grade KIRC samples according to the Fuhrman/WHO/ISUP scale. Moreover, a directly proportional correlation was observed between SHH and VEGFA immunoreactivity in TNM 3 + 4 and Fuhrman/ISUP/WHO 3 + 4 tumor tissues as well as in samples of patients with shorter survival. We also observed an association between shorter patient survival as well as increased and decreased immunoreactivity, of the VEGFA and GLI1, respectively. The aforementioned findings suggest that the expression pattern of SHH, GLI1 and VEGFA demonstrates prognostic potential in KIRC.

Usability of serum hedgehog signalling proteins as biomarkers in canine mammary carcinomas

BACKGROUND

The hedgehog signalling pathway has been implicated in tumourigenesis and progression of many tumour types. This pathway has recently emerged as a therapeutic target, and inhibitors of hedgehog signalling have gained considerable attention. In dogs, the roles of hedgehog signals in several types of tumours have been investigated, but their relationship with canine mammary gland tumours (MGTs) has not been established. This study aimed to evaluate the expression of sonic hedgehog (SHH) and glioma-associated oncogene 1 (GLI-1) in the serum and mammary tumour tissues of dogs.

RESULTS

SHH and GLI-1 protein expression levels were significantly higher in MGT tissues than in normal mammary gland tissues, as well as in malignant MGT specimens than in benign MGT specimens. Serum levels of SHH and GLI-1 were higher in MGT patients than in healthy controls (p < .001 and .001, respectively). Serum SHH level showed a statistically significant relationship with metastatic status (p = .01), and serum GLI-1 level showed a statistically significant relationship with histologic grade (p = 0.048) and metastatic status (p = 0.007). Serum hedgehog signalling protein levels were not significantly associated with breed size, sex, tumour size, or histologic type.

CONCLUSIONS

Hedgehog signalling protein expression in canine MGT tissue and serum differed according to the histological classification (benign and malignant) and metastatic status, indicating a relationship between the hedgehog signalling pathway and canine MGT. Thus, the hedgehog signalling pathway may serve as a new biomarker and therapeutic target in canine MGT patients.

MicroRNAs mediated interaction of tumor microenvironment cells with breast cancer cells during bone metastasis

Breast cancer (BC) bone metastasis is primarily osteolytic and has limited therapeutic options. Metastasized BC cells prime the secondary environment in bone by forming a tumor niche, which favors their homing and colonization. The tumor microenvironment (TME) is primarily generated by the cancer cells. Bone TME is an intricate network of multiple cells, including altered bone, tumor, stromal, and immune cells. Recent findings highlight the significance of small non-coding microRNAs (miRNAs) in influencing TME during tumor metastasis. MiRNAs from TME-resident cells facilitate the interaction between the tumor and its microenvironment, thereby regulating the biological processes of tumors. These miRNAs can serve as oncogenes or tumor suppressors. Hence, both miRNA inhibitors and mimics are extensively utilized in pre-clinical trials for modulating the phenotypes of tumor cells and associated stromal cells. This review briefly summarizes the recent developments on the functional role of miRNAs secreted directly or indirectly from the TME-resident cells in facilitating tumor growth, progression, and metastasis. This information would be beneficial in developing novel targeted therapies for BC.

Delineating highly transcribed noncoding elements landscape in breast cancer

Highly transcribed noncoding elements (HTNEs) are critical noncoding elements with high levels of transcriptional capacity in particular cohorts involved in multiple cellular biological processes. Investigation of HTNEs with persistent aberrant expression in abnormal tissues could be of benefit in exploring their roles in disease occurrence and progression. Breast cancer is a highly heterogeneous disease for which early screening and prognosis are exceedingly crucial. In this study, we developed a HTNE identification framework to systematically investigate HTNE landscapes in breast cancer patients and identified over ten thousand HTNEs. The robustness and rationality of our framework were demonstrated via public datasets. We revealed that HTNEs had significant chromatin characteristics of enhancers and long noncoding RNAs (lncRNAs) and were significantly enriched with RNA-binding proteins as well as targeted by miRNAs. Further, HTNE-associated genes were significantly overexpressed and exhibited strong correlations with breast cancer. Ultimately, we explored the subtype-specific transcriptional processes associated with HTNEs and uncovered the HTNE signatures that could classify breast cancer subtypes based on the properties of hormone receptors. Our results highlight that the identified HTNEs as well as their associated genes play crucial roles in breast cancer progression and correlate with subtype-specific transcriptional processes of breast cancer.

Is cholesterol a risk factor for breast cancer incidence and outcome?

Cholesterol plays important roles in many physiological processes, including cell membrane structure and function, hormone synthesis, and the regulation of cellular homeostasis. The role of cholesterol in breast cancer is complex, and some studies have suggested that elevated cholesterol levels may be associated with an increased risk of developing breast cancer, while others have found no significant association. On the other hand, other studies have shown that, for total cholesterol and plasma HDL-associated cholesterol levels, there was inverse association with breast cancer risk. One possible mechanism by which cholesterol may contribute to breast cancer risk is as a key precursor of estrogen. Other potential mechanisms by which cholesterol may contribute to breast cancer risk include its role in inflammation and oxidative stress, which have been linked to cancer progression. Cholesterol has also been shown to play a role in signaling pathways regulating the growth and proliferation of cancer cells. In addition, recent studies have shown that cholesterol metabolism can generate tumor promoters such as cholesteryl esters, oncosterone, 27-hydroxycholesterol but also tumor suppressor metabolites such as dendrogenin A. This review summarizes some of the most important clinical studies that have evaluated the role of cholesterol or its derivatives in breast cancer. It also addresses the role of cholesterol and its derivatives at the cellular level.

Hedgehog signaling in tissue homeostasis, cancers, and targeted therapies

The past decade has seen significant advances in our understanding of Hedgehog (HH) signaling pathway in various biological events. HH signaling pathway exerts its biological effects through a complex signaling cascade involved with primary cilium. HH signaling pathway has important functions in embryonic development and tissue homeostasis. It plays a central role in the regulation of the proliferation and differentiation of adult stem cells. Importantly, it has become increasingly clear that HH signaling pathway is associated with increased cancer prevalence, malignant progression, poor prognosis and even increased mortality. Understanding the integrative nature of HH signaling pathway has opened up the potential for new therapeutic targets for cancer. A variety of drugs have been developed, including small molecule inhibitors, natural compounds, and long non-coding RNA (LncRNA), some of which are approved for clinical use. This review outlines recent discoveries of HH signaling in tissue homeostasis and cancer and discusses how these advances are paving the way for the development of new biologically based therapies for cancer. Furthermore, we address status quo and limitations of targeted therapies of HH signaling pathway. Insights from this review will help readers understand the function of HH signaling in homeostasis and cancer, as well as opportunities and challenges of therapeutic targets for cancer.

Signaling pathways governing the maintenance of breast cancer stem cells and their therapeutic implications

Breast cancer stem cells (BCSCs) represent a distinct subpopulation of cells with the ability to self-renewal and differentiate into phenotypically diverse tumor cells. The involvement of CSC in treatment resistance and cancer recurrence has been well established. Numerous studies have provided compelling evidence that the self-renewal ability of cancer stem cells is tightly regulated by specific signaling pathways, which exert critical roles to maintain an undifferentiated phenotype and prevent the differentiation of CSCs. Signaling pathways such as Wnt/β-catenin, NF-κB, Notch, Hedgehog, TGF-β, and Hippo have been implicated in the promotion of self-renewal of many normal and cancer stem cells. Given the pivotal role of BCSCs in driving breast cancer aggressiveness, targeting self-renewal signaling pathways holds promise as a viable therapeutic strategy for combating this disease. In this review, we will discuss the main signaling pathways involved in the maintenance of the self-renewal ability of BCSC, while also highlighting current strategies employed to disrupt the signaling molecules associated with stemness.

Circular RNAs with protein-coding ability in oncogenesis

As ubiquitously expressed transcripts in eukaryotes, circular RNAs (circRNAs) are covalently closed and lack a 5'-cap and 3'-polyadenylation (poly (A)) tail. Initially, circRNAs were considered non-coding RNA (ncRNA), and their roles as sponging molecules to adsorb microRNAs have been extensively reported. However, in recent years, accumulating evidence has demonstrated that circRNAs could encode functional polypeptides through the initiation of translation mediated by internal ribosomal entry sites (IRESs) or N6-methyladenosine (m6A). In this review, we collectively discuss the biogenesis, cognate mRNA products, regulatory mechanisms, aberrant expression and biological phenotypes or clinical relevance of all currently reported, cancer-relevant protein-coding circRNAs. Overall, we provide a comprehensive overview of circRNA-encoded proteins and their physiological and pathological functions.

Expression Pattern of Sonic Hedgehog, Patched and Smoothened in Clear Cell Renal Carcinoma

Clear cell renal cell carcinoma (ccRCC) is the deadliest neoplasm of the urinary tract, and we are still far from completely understanding ccRCC development and treatment. The renal tissue paraffin blocks (20) of patients with ccRCC were collected at the University Hospital in Split from 2019 to 2020, and tissue sections were stained with patched (PTCH), anti-smoothened (SMO) and anti-Sonic Hedgehog (SHH) antibodies. SHH was highly expressed (31.9%) in grade 1 tumour, it being higher than all other grades and the control (p < 0.001-p < 0.0001). The trend of a linear decrease in the expression of SHH was observed with the progression of the tumour grade (p < 0.0001). PTCH expression was significantly lower in grades 1 and 2 in comparison to the control (p < 0.01) and grade 4 (p < 0.0001). A significant increase in the expression of SMO was found in grade 4 compared to all other grades (p < 0.0001) and the control (p < 0.001). The strong expression of SHH was observed in carcinoma cells of the G1 stage with a diffuse staining pattern (>50% of neoplastic cells). Stroma and/or inflammatory infiltrate display no staining and no expression of SHH in G1 and G2, while mild focal staining (10-50% of neoplastic cells) was observed in G3 and G4. Patients with high PTCH and low SMO expression had significant time survival differences (p = 0.0005 and p = 0.029, respectively). Therefore, high levels of PTCH and low levels of SMO expression are important markers of better survival rates in ccRCC patients.

Hedgehog Signaling Regulates Treg to Th17 Conversion Through Metabolic Rewiring in Breast Cancer

The tumor immune microenvironment dynamically evolves to support tumor growth and progression. Immunosuppressive regulatory T cells (Treg) promote tumor growth and metastatic seeding in patients with breast cancer. Deregulation of plasticity between Treg and Th17 cells creates an immune regulatory framework that enables tumor progression. Here, we discovered a functional role for Hedgehog (Hh) signaling in promoting Treg differentiation and immunosuppressive activity, and when Hh activity was inhibited, Tregs adopted a Th17-like phenotype complemented by an enhanced inflammatory profile. Mechanistically, Hh signaling promoted O-GlcNAc modifications of critical Treg and Th17 transcription factors, Foxp3 and STAT3, respectively, that orchestrated this transition. Blocking Hh reprogramed Tregs metabolically, dampened their immunosuppressive activity, and supported their transdifferentiation into inflammatory Th17 cells that enhanced the recruitment of cytotoxic CD8+ T cells into tumors. Our results demonstrate a previously unknown role for Hh signaling in the regulation of Treg differentiation and activity and the switch between Tregs and Th17 cells in the tumor microenvironment.

Identification of a centrosome-related prognostic signature for breast cancer

Background

As the major microtubule organizing center in animal cells, the centrosome is implicated with human breast tumor in multiple ways, such as promotion of tumor cell immune evasion. Here, we aimed to detect the expression of centrosome-related genes (CRGs) in normal and malignant breast tissues, and construct a novel centrosome-related prognostic model to discover new biomarkers and screen drugs for breast cancer.

Methods

We collected CRGs from the public databases and literature. The differentially expressed CRGs between normal and malignant breast tissues were identified by the DESeq2. Univariate Cox and LASSO regression analyses were conducted to screen candidate prognostic CRGs and develop a centrosome-related signature (CRS) to score breast cancer patients. We further manipulated and visualized data from TCGA, GEO, IMvigor210, TCIA and TIMER to explore the correlation between CRS and patient outcomes, clinical manifestations, mutational landscapes, tumor immune microenvironments, and responses to diverse therapies. Single cell analyses were performed to investigate the difference of immune cell landscape between high- and low-risk group patients. In addition, we constructed a nomogram to guide clinicians in precise treatment.

Results

A total of 726 CRGs were collected from the public databases and literature. PSME2, MAPK10, EIF4EBP1 were screened as the prognostic genes in breast cancer. Next, we constructed a centrosome-related prognostic signature and validated its efficacy based on the genes for predicting the survival of breast cancer patients. The high-risk group patients had poor prognoses, the area under the ROC curve for 1-, 3-, and 5-year overall survival (OS) was 0.77, 0.67, and 0.65, respectively. The predictive capacity of CRS was validated by other datasets from GEO dataset. In addition, high-risk group patients exhibited elevated level of mutational landscapes and decreased level of immune infiltration, especially T and B lymphocytes. In terms of treatment responses, patients in the high-risk group were found to be resistant to immunotherapy but sensitive to chemotherapy. Moreover, we screened a series of candidate anticancer drugs with high sensitivity in the high-risk group.

Conclusion

Our work exploited a centrosome-related prognostic signature and developed a predictive nomogram capable of accurately predicting breast cancer OS. The above discoveries provide deeper insights into the vital roles of the centrosome and contribute to the development of personalized treatment for breast cancer.

Solasodine suppress MCF7 breast cancer stem-like cells via targeting Hedgehog/Gli1

BACKGROUND

Recently, a novel therapy to treat cancer has been to target cancer stem-like cells (CSCs). The aim of this study was to investigate the effect of solasodine, a steroidal alkaloid isolated from Solanum incanum L., on MCF7 CSCs and to understand the compound's underlying mechanism of action.

METHOD

A tumorsphere formation assay was used to evaluate the effects of solasodine on the proliferation and self-renewal ability of MCF7 CSCs. The level of expression of proteins associated with cancer stemness markers and Hh signaling mediators was determined. The interaction between solasodine and Gli1 was calculated by molecular docking and further demonstrated by cellular thermal shift assay.

RESULTS

Solasodine significantly decreased the proliferation of MCF7 tumorspheres and showed a stronger cytotoxicity on breast cancer cells with higher levels of Gli1 expression. The results showed that the levels of CD44 and ALDH1 expression were suppressed. Furthermore, expression of CD24 was enhanced by solasodine, via a mechanism that involved dampening Gli1 expression and blocking the nuclear translocation of this protein in MCF7 tumorspheres. Computational studies predicted that solasodine showed a high affinity with the Gli1 zinc finger domain that resulted from hydrogen-bonds to the THR243 and ASP216 amino acids residues. In addition, solasodine specifically bound with Gli1 and enhanced Gli1 protein stability in MCF7 cells.

CONCLUSION

Here, our findings indicated that solasodine can directly suppresses Hh/Gli1 signaling, and is a novel anticancer candidate that targets CSCs.

Higher Expressions of SHH and AR Are Associated with a Positive Receptor Status and Have Impact on Survival in a Cohort of Croatian Breast Cancer Patients

Breast cancers (BC) are usually classified into four molecular subtypes according to the expression of estrogen (ER), progesterone (PR), and human epidermal growth factor 2 (HER2) receptors and proliferation marker Ki-67. Despite available anti-hormonal therapies and due to the inherent propensity of some subtypes to develop metastasis, there is a permanent need to discover new prognostic and predictive biomarkers, as well as therapeutic targets for BC. In this study, we used immunohistochemical staining to determine the expression of androgen receptor (AR) and sonic hedgehog protein (SHH), the main ligand of the Hedgehog-GLI (HH-GLI) signaling pathway, in 185 archival primary BC tissue samples and correlated it with clinicopathological characteristics, molecular subtypes, receptors statuses, and survival in a cohort of Croatian BC patients. Results showed that higher SHH and AR expressions were associated with positive receptor status, but increased SHH expression had a negative impact on survival in receptor-negative BCs. On the contrary, higher AR expression was mostly protective. However, multivariate analysis showed that only higher AR expression could be considered as an independent prognostic biomarker for poorer overall survival in triple-negative breast cancer patients (TNBC) (HR 10.9, 95% CI 1.43-83.67; p = 0.021), what could be Croatian population-related. SHH could be a potential target for treating TNBCs and HER2-enriched BCs, in cases where HH-GLI signaling is canonical (SHH-dependent).

Hedgehog/GLI signaling in hematopoietic development and acute myeloid leukemia—From bench to bedside

While the underlying genetic alterations and biology of acute myeloid leukemia (AML), an aggressive hematologic malignancy characterized by clonal expansion of undifferentiated myeloid cells, have been gradually unraveled in the last decades, translation into clinical treatment approaches has only just begun. High relapse rates remain a major challenge in AML therapy and are to a large extent attributed to the persistence of treatment-resistant leukemic stem cells (LSCs). The Hedgehog (HH) signaling pathway is crucial for the development and progression of multiple cancer stem cell driven tumors, including AML, and has therefore gained interest as a therapeutic target. In this review, we give an overview of the major components of the HH signaling pathway, dissect HH functions in normal and malignant hematopoiesis, and specifically elaborate on the role of HH signaling in AML pathogenesis and resistance. Furthermore, we summarize preclinical and clinical HH inhibitor studies, leading to the approval of the HH pathway inhibitor glasdegib, in combination with low-dose cytarabine, for AML treatment.

Scalable multiplex co-fractionation/mass spectrometry platform for accelerated protein interactome discovery

Co-fractionation/mass spectrometry (CF/MS) enables the mapping of endogenous macromolecular networks on a proteome scale, but current methods are experimentally laborious, resource intensive and afford lesser quantitative accuracy. Here, we present a technically efficient, cost-effective and reproducible multiplex CF/MS (mCF/MS) platform for measuring and comparing, simultaneously, multi-protein assemblies across different experimental samples at a rate that is up to an order of magnitude faster than previous approaches. We apply mCF/MS to map the protein interaction landscape of non-transformed mammary epithelia versus breast cancer cells in parallel, revealing large-scale differences in protein-protein interactions and the relative abundance of associated macromolecules connected with cancer-related pathways and altered cellular processes. The integration of multiplexing capability within an optimized workflow renders mCF/MS as a powerful tool for systematically exploring physical interaction networks in a comparative manner.

Co-fractionation/mass spectrometry (CF/MS) allows mapping protein interactomes but efficiency and quantitative accuracy are limited. Here, the authors develop a reproducible multiplexed CF/MS method and apply it to characterize interactome rewiring in breast cancer cells.

Garcinone C Suppresses Tumorsphere Formation and Invasiveness by Hedgehog/Gli1 Signaling in Colorectal Cancer Stem-like Cells

Hyperactivation of hedgehog signaling occurs in colorectal cancer stem-like cells (CSCs), a rare subpopulation, potentially involved in metastasis, chemotherapy resistance, and cancer relapse. Garcinone C, a xanthone isolated from mangosteen (Garcinia mangostana), suppresses colorectal cancer in vivo and in vitro by inhibiting Gli1-dependent noncanonical hedgehog signaling. Herein, we investigated the effect of garcinone C on cancer stemness and invasiveness in colorectal cancer; Gli1 was noted as pivotal in maintaining stemness and invasiveness in HCT116 and HT29 CSCs. Garcinone C inhibited the proliferation and self-renewal of HCT116 and HT29 CSCs. Colon cancer stemness markers such as CD44, CD133, ALDH1, and Nanog were significantly decreased by garcinone C. Computational studies showed that garcinone C showed a high affinity with the Gli1 protein ZF domain by forming hydrogen bonds with amino acid residues of ASP244, ARG223, and ASP216. Besides, MG132 blocked the effects of garcinone C on Gli1. Thus, garcinone C suppressed colorectal CSCs by binding to Gli1 and enhancing its degradation. MMP2 and MMP9 levels, invasive-related markers, were increased in HCT116 CSCs but decreased by garcinone C. E-cadherin level was reduced in HCT116 CSCs, while the presence of garcinone C was restored. Garcinone C inhibited the proliferation and invasiveness of colorectal CSCs by targeting Gli1-dependent Hh signaling. Garcinone C may be a potent natural agent against colorectal cancer relapse.

Hedgehog signaling regulates the development and treatment of glioblastoma (Review)

Glioblastoma (GBM) is the most common and fatal malignant tumor type of the central nervous system. GBM affects public health and it is important to identify biomarkers to improve diagnosis, reduce drug resistance and improve prognosis (e.g., personalized targeted therapies). Hedgehog (HH) signaling has an important role in embryonic development, tissue regeneration and stem cell renewal. A large amount of evidence indicates that both normative and non-normative HH signals have an important role in GBM. The present study reviewed the role of the HH signaling pathway in the occurrence and progression of GBM. Furthermore, the effectiveness of drugs that target different components of the HH pathway was also examined. The HH pathway has an important role in reversing drug resistance after GBM conventional treatment. The present review highlighted the relevance of HH signaling in GBM and outlined that this pathway has a key role in the occurrence, development and treatment of GBM.

Embryonic Programs in Cancer and Metastasis—Insights From the Mammary Gland

Cancer is characterized as a reversion of a differentiated cell to a primitive cell state that recapitulates, in many aspects, features of embryonic cells. This review explores the current knowledge of developmental mechanisms that are essential for embryonic mouse mammary gland development, with a particular focus on genes and signaling pathway components that are essential for the induction, morphogenesis, and lineage specification of the mammary gland. The roles of these same genes and signaling pathways in mammary gland or breast tumorigenesis and metastasis are then summarized. Strikingly, key embryonic developmental pathways are often reactivated or dysregulated during tumorigenesis and metastasis in processes such as aberrant proliferation, epithelial-to-mesenchymal transition (EMT), and stem cell potency which affects cellular lineage hierarchy. These observations are in line with findings from recent studies using lineage tracing as well as bulk- and single-cell transcriptomics that have uncovered features of embryonic cells in cancer and metastasis through the identification of cell types, cell states and characterisation of their dynamic changes. Given the many overlapping features and similarities of the molecular signatures of normal development and cancer, embryonic molecular signatures could be useful prognostic markers for cancer. In this way, the study of embryonic development will continue to complement the understanding of the mechanisms of cancer and aid in the discovery of novel therapeutic targets and strategies.

Long-Noncoding RNA ANCR Activates the Hedgehog Signaling Pathway to Promote Basal Cell Carcinoma Progression by Binding to PTCH

Purpose

The long non-coding RNA (lncRNA) anti-differentiation noncoding RNA (ANCR) is closely related to the occurrence and development of various malignancies. However, its expression and potential role in basal cell carcinoma (BCC) have not been established. In this study, we characterized the effects of ANCR in BCC and its underlying mechanism.

Methods

The expression of ANCR in BCC tissues and cells was detected by qRT-PCR. Proliferation, invasion, migration and apoptosis of ANCR overexpressed or knock down TE354.T and A431 cells were examined by CCK8, transwell assay, wound healing assay and flow cytometry analysis, respectively. Western blot was performed to measure the expression of apoptosis-related proteins (BAX, BCL2 and Cleaved-caspase3), epithelial-mesenchymal transformation-related proteins (E-cadherin, N-cadherin, vimentin and β-catenin), and Hedgehog-pathway-related proteins (PTCH, GLI1 and SMO). RNA pull-down assay was used to analyze the relationship between ANCR and PTCH. The effect of ANCR on BCC growth in vivo was analyzed using xenograft model. TUNEL assay was used to determine the cell apoptosis.

Results

ANCR and Hedgehog pathway were more highly expressed in BCC tissues than in adjacent normal tissues. ANCR overexpression substantially promoted BCC cell proliferation, invasion, and migration, inhibited apoptosis, and up-regulated BCL2 and decreased the expression of BAX and Cleaved-caspase3 proteins. Additionally, the upregulation of N-cadherin, vimentin, β-catenin, PTCH, GLI1, and SMO expression, and downregulation of E-cadherin expression were observed after ANCR overexpression. Moreover, ANCR knockdown had the opposite effects. An RNA pull-down assay further revealed that ANCR is specifically bound to PTCH. In vivo experiments also showed that ANCR overexpression significantly increased tumor growth and decreased apoptosis, which was reversed by cyclopamine, a specific inhibitor of the Hedgehog signaling pathway.

Conclusion

ANCR activates the Hedgehog signaling pathway by binding to PTCH, thereby promoting BCC progression; accordingly, ANCR could be a candidate therapeutic target in BCC.

Expression of yes‑associated protein, β‑catenin and smoothened, and their clinical significance in invasive breast cancer

The expression profile and role of yes-associated protein (YAP) in occurrence and development of breast cancer is ambiguous. The present study aimed to explore the relationship among the YAP, β-catenin and smoothened (SMO) signaling pathways to provide a theoretical basis for the clinical diagnosis and treatment of invasive breast cancer. Immunohistochemistry was used to determine the protein expression levels of YAP, β-catenin and SMO in tumor, tumor-adjacent and normal breast tissue. The possible association between the expression levels of these three proteins and the clinicopathological features of patients with breast cancer was then analyzed by the χ² test. The protein expression of YAP was found to be downregulated, whilst β-catenin and SMO expression were found to be upregulated in tumor tissues as compared with that in normal breast tissues. In addition, the expression of YAP in breast cancer tissues was found to be associated with that of human epidermal growth factor receptor 2 (HER2), progesterone and estrogen receptors. By contrast, the protein expression of β-catenin and SMO in breast cancer tissues was only associated with HER2. There was a negative correlation between the expression of YAP and SMO protein in breast cancer tissues. Compared with that in the changes in each of YAP, β-catenin and SMO protein expression levels individually, their combined changes in expression were demonstrated to associate significantly with the tumor histological grade. To conclude, data from the present study suggest that the combined protein expression of YAP, β-catenin and SMO can be used as a prognostic indicator for the treatment of invasive breast cancer.

Targeting GLI1 Transcription Factor for Restoring Iodine Avidity with Redifferentiation in Radioactive-Iodine Refractory Thyroid Cancers

Simple Summary

Thyroid cancers have an excellent prognosis by standard therapy of surgery followed by radioactive-iodine therapy. However, metastatic thyroid cancers do not response to radioactive-iodine therapy by losing iodine avidity. Therefore, reversing iodine avidity to metastatic thyroid cancers gives a new chance of applying radioactive-iodine therapy to the cancers. In the current study, we found that GLI1 knockdown can revert iodine non-avid thyroid cancers to iodine avid cancers by increasing expression of thyroid-specific proteins. Restoration of iodine avidity in thyroid cancers makes the cancers sensitive to radioactive-iodine therapy again. Therefore, the GLI1 can be a potential therapeutic target of radioactive-iodine resistant thyroid cancers.

Abstract

Radioactive-iodine (RAI) therapy is the mainstay for patients with recurrent and metastatic thyroid cancer. However, many patients exhibit dedifferentiation characteristics along with lack of sodium iodide symporter (NIS) functionality, low expression of thyroid-specific proteins, and poor RAI uptake, leading to poor prognosis. Previous studies have demonstrated the effect of GLI family zinc finger 1 (GLI1) inhibition on tumor growth and apoptosis. In this study, we investigated the role of GLI1 in the context of redifferentiation and improvement in the efficacy of RAI therapy for thyroid cancer. We evaluated GLI1 expression in several thyroid cancer cell lines and selected TPC-1 and SW1736 cell lines showing the high expression of GLI. We performed GLI1 knockdown and evaluated the changes of thyroid-specific proteins expression, RAI uptake and I-131-mediated cytotoxicity. The effect of GANT61 (GLI1 inhibitor) on endogenous NIS expression was also assessed. Endogenous NIS expression upregulated by inhibiting GLI1, in addition, increased expression level in plasma membrane. Also, GLI1 knockdown increased expression of thyroid-specific proteins. Restoration of thyroid-specific proteins increased RAI uptake and I-131-mediated cytotoxic effect. Treatment with GANT61 also increased expression of endogenous NIS. Targeting GLI1 can be a potential strategy with redifferentiation for restoring RAI avidity in dedifferentiated thyroid cancers.

The Sonic Hedgehog Pathway Modulates Survival, Proliferation, and Differentiation of Neural Progenitor Cells under Inflammatory Stress In Vitro

The Sonic Hedgehog protein (Shh) has been extensively researched since its discovery in 1980. Its crucial role in early neurogenesis and endogenous stem cells of mature brains, as well as its recently described neuroprotective features, implicate further important effects on neuronal homeostasis. Here, we investigate its potential role in the survival, proliferation, and differentiation of neural precursors cells (NPCs) under inflammatory stress as a potential adjunct for NPC-transplantation strategies in spinal cord injury (SCI) treatment. To this end, we simulated an inflammatory environment in vitro using lipopolysaccharide (LPS) and induced the Shh-pathway using recombinant Shh or blocked it using Cyclopamine, a potent Smo inhibitor. We found that Shh mediates the proliferation and neuronal differentiation potential of NPCs in vitro, even in an inflammatory stress environment mimicking the subacute phase after SCI. At the same time, our results indicate that a reduction of the Shh-pathway activation by blockage with Cyclopamine is associated with reduced NPC-survival, reduced neuronal differentiation and increased astroglial differentiation. Shh might thus, play a role in endogenous NPC-mediated neuroregeneration or even be a potent conjunct to NPC-based therapies in the inflammatory environment after SCI.

Exploration of the immune microenvironment of breast cancer in large population cohorts

Tumor immune microenvironment is associated with tumor progression. However, previous studies have not fully explored the breast cancer (BC) immune microenvironment. All the data analyzed in this study were obtained from the open-access database, including The Cancer Genome Atlas, Gene Expression Omnibus (TCGA), and cBioPortal databases. R software v4.0 and SPSS 13.0 were used to perform all the statistical analysis. Firstly, the clinical and expression profile information of TCGA, GSE20685, GSE20711, GSE48390, GSE58812, and METABRIC cohorts was collected. Then, 53 immune terms were quantified using the single-sample Gene Set Enrichment Analysis (ssGSEA) algorithm. A prognosis model based on HER2_Immune_PCA, IL12_score, IL13_score, IL4_score, and IR7_score was established, which showed great prognosis prediction efficiency in both training group and validation group. A nomogram was then established for a better clinical application. Clinical correlation showed that elderly BC patients might have a higher riskscore. Pathway enrichment analysis showed that the pathway of oxidative phosphorylation, E2F targets, hedgehog signaling, adipogenesis, DNA repair, glycolysis, heme metabolism, and mTORC1 signaling was activated in the high-risk group. Moreover, Tumor Immune Dysfunction and Exclusion and Genomics of Drug Sensitivity in Cancer analysis showed that low-risk patients might be more sensitive to PD-1 therapy, cisplatin, gemcitabine, paclitaxel, and sunitinib. Finally, four genes, XCL1, XCL2, TNFRSF17, and IRF4, were identified for risk group classification. In summary, our signature is a useful tool for the prognosis and prediction of the drug sensitivity of BC.

Propofol Inhibits Thyroid Cancer Cell Proliferation, Migration, and Invasion by Suppressing SHH and PI3K/AKT Signaling Pathways via the miR-141-3p/BRD4 Axis

Objective

This study explores the effect and mechanism of propofol for thyroid tumor.

Methods

Culture human normal thyroid cells Nthy-ori 3-1 and thyroid cancer cell line TPC-1. TPC-1 cells were divided into the propofol group (treated with propofol), miR-141-3p group (transfected with the miR-141-3p mimic), negative control group (transfected with miR-NC), miR-141-3p + pcDNA-BRD4 group (transfected with the miR-141-3p mimic and pcDNA-BRD4), miR-141-3p + pcDNA group (transfected with the miR-141-3p mimic and pcDNA), siBRD4 group (transfected with siBRD4), and si-control group (transfected with si-control). The detection of miR-141-3p and BRD4 expression in cells was done by RT-qPCR, and the dual-luciferase reporter gene method and western blotting were used to verify the targeting relationship between miR-141-3p and BRD4. MTT method was used to test cell proliferation, transwell method was used to test cell migration and invasion, and western blotting was used to test SHH, GLI1, p-PI3K, and p-AKT protein expression.

Results

Compared with Nthy-ori 3-1 cells, the expression of miR-141-3p in TPC-1 cells was markedly decreased. Propofol treatment and excessive expression of miR-141-3p could influence the phenotype of TPC-1 cells. BRD4 is one of the target genes of miR-141-3p, and its expression is negatively regulated by miR-141-3p. Overexpression of BRD4 can partially reverse the restraining effect of miR-141-3p on the TPC-1 cell phenotype. Both miR-141-3p and BRD4 can regulate the activity of SHH and PI3K/AKT signaling pathways.

Conclusion

Propofol can inhibit the activity of SHH and PI3K/AKT pathways by targeting downregulating BRD4 through miR-141-3p, thereby inhibiting the phenotype of TPC-1 cells.

Novel Pathways for Targeting Tumor Angiogenesis in Metastatic Breast Cancer

Breast cancer is the most common cancer affecting women and is the second leading cause of cancer related death worldwide. Angiogenesis, the process of new blood vessel development from pre-existing vasculature, has been implicated in the growth, progression, and metastasis of cancer. Tumor angiogenesis has been explored as a key therapeutic target for decades, as the blockade of this process holds the potential to reduce the oxygen and nutrient supplies that are required for tumor growth. However, many existing anti-angiogenic approaches, such as those targeting Vascular Endothelial Growth Factor, Notch, and Angiopoietin signaling, have been associated with severe side-effects, limited survival advantage, and enhanced cancer regrowth rates. To address these setbacks, alternative pathways involved in the regulation of tumor angiogenesis are being explored, including those involving Bone Morphogenetic Protein-9 signaling, the Sonic Hedgehog pathway, Cyclooxygenase-2, p38-mitogen-activated protein kinase, and Chemokine Ligand 18. This review article will introduce the concept of tumor angiogenesis in the context of breast cancer, followed by an overview of current anti-angiogenic therapies, associated resistance mechanisms and novel therapeutic targets.

Advances in glioma-associated oncogene (GLI) inhibitors for cancer therapy

The Hedgehog/Glioma-associated oncogene homolog (HH/GLI) signaling pathway regulates self-renewal of rare and highly malignant cancer stem cells, which have been shown to account for the initiation and maintenance of tumor growth as well as for drug resistance, metastatic spread and relapse. As an important component of the Hh signaling pathway, glioma-associated oncogene (GLI) acts as a key signal transmission hub for various signaling pathways in many tumors. Here, we review direct and indirect inhibitors of GLI; summarize the abundant active structurally diverse natural GLI inhibitors; and discuss how to better develop and utilize GLI inhibitors to solve the problem of drug resistance in tumors of interest. In summary, GLI inhibitors will be promising candidates for various cancer treatments.

Hedgehog Pathway Inhibitors against Tumor Microenvironment

Targeting the hedgehog (HH) pathway to treat aggressive cancers of the brain, breast, pancreas, and prostate has been ongoing for decades. Gli gene amplifications have been long discovered within malignant glioma patients, and since then, inhibitors against HH pathway-associated molecules have successfully reached the clinical stage where several of them have been approved by the FDA. Albeit this success rate implies suitable progress, clinically used HH pathway inhibitors fail to treat patients with metastatic or recurrent disease. This is mainly due to heterogeneous tumor cells that have acquired resistance to the inhibitors along with the obstacle of effectively targeting the tumor microenvironment (TME). Severe side effects such as hyponatremia, diarrhea, fatigue, amenorrhea, nausea, hair loss, abnormal taste, and weight loss have also been reported. Furthermore, HH signaling is known to be involved in the regulation of immune cell maturation, angiogenesis, inflammation, and polarization of macrophages and myeloid-derived suppressor cells. It is critical to determine key mechanisms that can be targeted at different levels of tumor development and progression to address various clinical issues. Hence current research focus encompasses understanding how HH controls TME to develop TME altering and combinatorial targeting strategies. In this review, we aim to discuss the pros and cons of targeting HH signaling molecules, understand the mechanism involved in treatment resistance, reveal the role of the HH pathway in anti-tumor immune response, and explore the development of potential combination treatment of immune checkpoint inhibitors with HH pathway inhibitors to target HH-driven cancers.

KIF21A regulates breast cancer aggressiveness and is prognostic of patient survival and tumor recurrence

PURPOSE

Invasion of carcinoma cells into surrounding tissue affects breast cancer staging, influences choice of treatment, and impacts on patient outcome. KIF21A is a member of the kinesin superfamily that has been well-studied in congenital extraocular muscle fibrosis. However, its biological relevance in breast cancer is unknown. This study investigated the functional roles of KIF21A in this malignancy and examined its expression pattern in breast cancer tissue.

METHODS

The function of KIF21A in breast carcinoma was studied in vitro by silencing its expression in breast cancer cells and examining the changes in cellular activities. Immunohistochemical staining of breast cancer tissue microarrays was performed to determine the expression patterns of KIF21A.

RESULTS

Knocking down the expression of KIF21A using siRNA in MDA-MB-231 and MCF7 human breast cancer cells resulted in significant decreases in tumor cell migration and invasiveness. This was associated with reduced Patched 1 expression and F-actin microfilaments. Additionally, the number of focal adhesion kinase- and paxillin-associated focal adhesions was increased. Immunohistochemical staining of breast cancer tissue microarrays showed that KIF21A was expressed in both the cytoplasmic and nuclear compartments of carcinoma cells. Predominance of cytoplasmic KIF21A was significantly associated with larger tumors and high grade cancer, and prognostic of cause-specific overall patient survival and breast cancer recurrence.

CONCLUSION

The data demonstrates that KIF21A is an important regulator of breast cancer aggressiveness and may be useful in refining prognostication of this malignant disease.

Interleukin-30 feeds breast cancer stem cells via CXCL10 and IL23 autocrine loops and shapes immune contexture and host outcome

Background

Breast cancer (BC) progression to metastatic disease is the leading cause of death in women worldwide. Metastasis is driven by cancer stem cells (CSCs) and signals from their microenvironment. Interleukin (IL) 30 promotes BC progression, and its expression correlates with disease recurrence and mortality. Whether it acts by regulating BCSCs is unknown and could have significant therapeutic implications.

Methods

Human (h) and murine (m) BCSCs were tested for their production of and response to IL30 by using flow cytometry, confocal microscopy, proliferation and sphere-formation assays, and PCR array. Immunocompetent mice were used to investigate the role of BCSC-derived IL30 on tumor development and host outcome. TCGA PanCancer and Oncomine databases provided gene expression data from 1084 and 75 hBC samples, respectively, and immunostaining unveiled the BCSC microenvironment.

Results

hBCSCs constitutively expressed IL30 as a membrane-anchored glycoprotein. Blocking IL30 hindered their proliferation and self-renewal efficiency, which were boosted by IL30 overexpression. IL30 regulation of immunity gene expression in human and murine BCSCs shared a significant induction of IL23 and CXCL10. Both immunoregulatory mediators stimulated BCSC proliferation and self-renewal, while their selective blockade dramatically hindered IL30-dependent BCSC proliferation and mammosphere formation. Orthotopic implantation of IL30-overexpressing mBCSCs, in syngeneic mice, gave rise to poorly differentiated and highly proliferating MYC⁺KLF4⁺LAG3⁺ tumors, which expressed CXCL10 and IL23, and were infiltrated by myeloid-derived cells, Foxp3⁺ T regulatory cells and NKp46⁺RORγt⁺ type 3 innate lymphoid cells, resulting in increased metastasis and reduced survival. In tumor tissues from patients with BC, expression of IL30 overlapped with that of CXCL10 and IL23, and ranked beyond the 95th percentile in a Triple-Negative enriched BC collection from the Oncomine Platform. CIBERSORTx highlighted a defective dendritic cell, CD4⁺ T and γδ T lymphocyte content and a prominent LAG3 expression in IL30^highversus IL30^low human BC samples from the TCGA PanCancer collection.

Conclusions

Constitutive expression of membrane-bound IL30 regulates BCSC viability by juxtacrine signals and via second-level mediators, mainly CXCL10 and IL23. Their autocrine loops mediate much of the CSC growth factor activity of IL30, while their paracrine effect contributes to IL30 shaping of immune contexture. IL30-related immune subversion, which also emerged from computational analyses, strongly suggests that targeting IL30 can restrain the BCSC compartment and counteract BC progression.

Quantitative Longitudinal Imaging Reveals that Inhibiting Hedgehog Activity Alleviates the Hypoxic Tumor Landscape

Metastases account for the majority of mortalities related to breast cancer. The onset and sustained presence of hypoxia strongly correlates with increased incidence of metastasis and unfavorable prognosis in patients with breast cancer. The Hedgehog (Hh) signaling pathway is dysregulated in breast cancer, and its abnormal activity enables tumor progression and metastasis. In addition to programming tumor cell behavior, Hh activity enables tumor cells to craft a metastasis-conducive microenvironment. Hypoxia is a prominent feature of growing tumors that impacts multiple signaling circuits that converge upon malignant progression. We investigated the role of Hh activity in crafting a hypoxic environment of breast cancer. We used radioactive tracer [¹⁸F]-fluoromisonidazole (FMISO) positron emission tomography (PET) to image tumor hypoxia. We show that tumors competent for Hh activity are able to establish a hypoxic milieu; pharmacologic inhibition of Hh signaling in a syngeneic mammary tumor model mitigates tumor hypoxia. Furthermore, in hypoxia, Hh activity is robustly activated in tumor cells and institutes increased HIF signaling in a VHL-dependent manner. The findings establish a novel perspective on Hh activity in crafting a hypoxic tumor landscape and molecularly navigating the tumor cells to adapt to hypoxic conditions. IMPLICATIONS: Importantly, we present a translational strategy of utilizing longitudinal hypoxia imaging to measure the efficacy of vismodegib in a preclinical model of triple-negative breast cancer.

Asymmetric cell division of mammary stem cells

Somatic stem cells are distinguished by their capacity to regenerate themselves and also to produce daughter cells that will differentiate. Self-renewal is achieved through the process of asymmetric cell division which helps to sustain tissue morphogenesis as well as maintain homeostasis. Asymmetric cell division results in the development of two daughter cells with different fates after a single mitosis. Only one daughter cell maintains "stemness" while the other differentiates and achieves a non-stem cell fate. Stem cells also have the capacity to undergo symmetric division of cells that results in the development of two daughter cells which are identical. Symmetric division results in the expansion of the stem cell population. Imbalances and deregulations in these processes can result in diseases such as cancer. Adult mammary stem cells (MaSCs) are a group of cells that play a critical role in the expansion of the mammary gland during puberty and any subsequent pregnancies. Furthermore, given the relatively long lifespans and their capability to undergo self-renewal, adult stem cells have been suggested as ideal candidates for transformation events that lead to the development of cancer. With the possibility that MaSCs can act as the source cells for distinct breast cancer types; understanding their regulation is an important field of research. In this review, we discuss asymmetric cell division in breast/mammary stem cells and implications on further research. We focus on the background history of asymmetric cell division, asymmetric cell division monitoring techniques, identified molecular mechanisms of asymmetric stem cell division, and the role asymmetric cell division may play in breast cancer.

Peptide-Targeted High-Density Lipoprotein Nanoparticles for Combinatorial Treatment against Metastatic Breast Cancer

The sonic hedgehog (SHH) signaling pathway exhibits aberrant activation in triple-negative breast cancer (TNBC), wherein it regulates several malignant phenotypes related to tumor metastasis. GANT61, an inhibitor of the SHH signaling pathway, may offer promise when administered in combination with conventional chemotherapy to treat metastatic TNBC. However, poor bioavailability and substantial off-target toxicity limit its clinical application. To address these limitations, we designed a peptide-functionalized dual-targeting delivery system encapsulating paclitaxel and GANT61 in tLyP-1 peptide-modified reconstituted high-density lipoprotein nanoparticle (tLyP-1-rHDL-PTX/GANT61 NP) for metastatic TNBC treatment. The apolipoprotein A-1 and tLyP-1 peptide modified on the surface of nanoparticles enable the delivery system to target tumor cells by binding to the overexpressed scavenger receptor B type I and neuropilin-1 receptor. Moreover, the tLyP-1 peptide also enables the deep tumor penetration of nanoparticles further facilitating paclitaxel and GANT61 delivery. Increased cellular uptake of the nanoparticles was observed in both MDA-MB-231, BT-549 tumor cells, and their 3D tumor spheroids. A series of in vitro experiments reveal that GANT61 was able to suppress key metastasis-related tumor cell activities including angiogenesis, migration, invasion, and stemness. Owing to more effective drug administration, the metastasis suppression efficiency of GANT61 was significantly enhanced by the dual-targeting tLyP-1-rHDL delivery system. Meanwhile, the codelivery of paclitaxel and GANT61 by dual-targeting tLyP-1-rHDL nanoparticles demonstrated superior efficiency of disrupting proliferation and inducing apoptosis in tumor cells compared with drug solutions. In a spontaneous metastasis breast cancer NCG mice model, the tLyP-1-rHDL-PTX/GANT61 nanoparticles exhibited highly tumor-specific distribution and result in significant inhibition of the primary tumor growth and dramatic reduction of lung metastasis without obvious side effects. The present work suggests that a combination of the SHH signaling pathway suppression and chemotherapy assisted by peptide-functionalized targeting tLyP-1-rHDL nanoparticles may provide a promising strategy for metastatic TNBC treatment.

Chemoresistance and Metastasis in Breast Cancer Molecular Mechanisms and Novel Clinical Strategies

Breast cancer is the most common malignant tumor in females worldwide. Chemotherapy is the standard breast cancer treatment; however, chemoresistance is often seen in patients with metastatic breast cancer. Owing to high heterogeneity, the mechanisms of breast cancer chemoresistance and metastasis have not been fully investigated. The possible molecular mechanisms of chemoresistance in breast cancer include efflux transporters, signaling pathways, non-coding RNAs, and cancer stem cells. However, to overcome this hurdle, the use of novel clinical strategies such as drug carriers, immunotherapy, and autophagy regulation, are being investigated. The goal of this review is to summarize the current data about the molecular mechanisms of breast cancer chemoresistance and the novel clinical strategies; thus, providing a useful clinical tool to explore optimal treatment for breast cancer.

Cancer stem cells in TNBC

Triple-negative breast cancer (TNBC) is a broad collection of breast cancer that tests negative for estrogen receptors (ER), progesterone receptors (PR), and excess human epidermal growth factor receptor 2 (HER2) protein. TNBC is considered to have poorer prognosis than other types of breast cancer because of a lack of effective therapeutic targets. The success of precision cancer therapies relies on the clarification of key molecular mechanisms that drive tumor growth and metastasis; however, TNBC is highly heterogeneous in terms of their cellular lineage composition and the molecular nature within each individual case. In particular, the rare and sometimes slow cycling cancer stem cells (CSCs) can provide effective means for TNBC to resist various treatments. Single cell analysis technologies, including single-cell RNA-seq (scRNA-seq) and proteomics, provide an avenue to unravel patient-level intratumoral heterogeneity by identifying CSCs populations, CSC biomarkers and the range of tumor microenvironment cellular constituents that contribute to tumor growth. This review discusses the emerging evidence for the role of CSCs in driving TNBC incidence and the therapeutic implications in manipulating molecular signaling against this rare cell population for the control of this deadly disease.

NKX6-1 mediates cancer stem-like properties and regulates sonic hedgehog signaling in leiomyosarcoma

Background

Leiomyosarcoma (LMS), the most common soft tissue sarcoma, exhibits heterogeneous and complex genetic karyotypes with severe chromosomal instability and rearrangement and poor prognosis.

Methods

Clinical variables associated with NKX6-1 were obtained from The Cancer Genome Atlas (TCGA). NKX6-1 mRNA expression was examined in 49 human uterine tissues. The in vitro effects of NXK6-1 in LMS cells were determined by reverse transcriptase PCR, western blotting, colony formation, spheroid formation, and cell viability assays. In vivo tumor growth was evaluated in nude mice.

Results

Using The Cancer Genome Atlas (TCGA) and human uterine tissue datasets, we observed that NKX6-1 expression was associated with poor prognosis and malignant potential in LMS. NKX6-1 enhanced in vitro tumor cell aggressiveness via upregulation of cell proliferation and anchorage-independent growth and promoted in vivo tumor growth. Moreover, overexpression and knockdown of NKX6-1 were associated with upregulation and downregulation, respectively, of stem cell transcription factors, including KLF8, MYC, and CD49F, and affected sphere formation, chemoresistance, NOTCH signaling and Sonic hedgehog (SHH) pathways in human sarcoma cells. Importantly, treatment with an SHH inhibitor (RU-SKI 43) but not a NOTCH inhibitor (DAPT) reduced cell survival in NKX6-1-expressing cancer cells, indicating that an SHH inhibitor could be useful in treating LMS. Finally, using the TCGA dataset, we demonstrated that LMS patients with high expression of NKX6-1 and HHAT, an SHH pathway acyltransferase, had poorer survival outcomes compared to those without.

Conclusions

Our findings indicate that NKX6-1 and HHAT play critical roles in the pathogenesis of LMS and could be promising diagnostic and therapeutic targets for LMS patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12929-021-00726-6.

Specific Protein 1 and p53 Interplay Modulates the Expression of the KCTD-Containing Cullin3 Adaptor Suppressor of Hedgehog 2

The Hedgehog (Hh) signaling pathway plays a crucial role in normal embryonic development and adult tissue homeostasis. On the other end, dysregulated Hh signaling triggers a prolonged mitogenic response that may prompt abnormal cell proliferation, favoring tumorigenesis. Indeed, about 30% of medulloblastomas (MBs), the most common malignant childhood cerebellar tumors, exhibit improper activation of the Hh signaling. The oncosuppressor KCASH2 has been described as a suppressor of the Hh signaling pathway, and low KCASH2 expression was observed in Hh-dependent MB tumor. Therefore, the study of the modulation of KCASH2 expression may provide fundamental information for the development of new therapeutic approaches, aimed to restore physiological KCASH2 levels and Hh inhibition. To this end, we have analyzed the TATA-less KCASH2 proximal promoter and identified key transcriptional regulators of this gene: Sp1, a TF frequently overexpressed in tumors, and the tumor suppressor p53. Here, we show that in WT cells, Sp1 binds KCASH2 promoter on several putative binding sites, leading to increase in KCASH2 expression. On the other hand, p53 is involved in negative regulation of KCASH2. In this context, the balance between p53 and Sp1 expression, and the interplay between these two proteins determine whether Sp1 acts as an activator or a repressor of KCASH2 transcription. Indeed, in p53^–/– MEF and p53 mutated tumor cells, we hypothesize that Sp1 drives promoter methylation through increased expression of the DNA methyltransferase 1 (DNMT1) and reduces KCASH2 transcription, which can be reversed by Sp1 inhibition or use of demethylating agents. We suggest therefore that downregulation of KCASH2 expression in tumors could be mediated by gain of Sp1 activity and epigenetic silencing events in cells where p53 functionality is lost. This work may open new venues for novel therapeutic multidrug approaches in the treatment of Hh-dependent tumors carrying p53 deficiency.

Light-inducible control of cellular proliferation and differentiation by a Hedgehog signaling inhibitor

The Hedgehog (Hh) signaling pathway is a major regulator of cell differentiation and proliferation. Aberrant activation of the Hh pathway has been implicated in several types of cancer. To understand the Hedgehog pathway and fight against related diseases, it is important to inhibit Hedgehog signaling in a targeted manner. However, no tools are available for the precise inhibition of Hh signaling in a spatiotemporal manner. In this study, we synthesized and evaluated the bioactivity of a light-inducible Hh pathway inhibitor (NVOC-SANT-75). NVOC-SANT-75 inhibits transcription factor Gli1 in NIH3T3 cells and controls proliferation and differentiation of primary cultured mouse cerebellar neurons in a light-irradiation-dependent manner. The light-inducible Hedgehog signaling inhibitors may be a new candidate for light-mediated cancer treatment.