CCR7 preservation via histone deacetylase inhibition promotes epithelial-mesenchymal transition of hepatocellular carcinoma cells

Exploration of prognostic and treatment markers in hepatocellular carcinoma via GPCR-related genes analysis

Background

G protein-coupled receptors (GPCRs), the biggest family of signaling receptors, account for 34 % of all the drug targets approved by the Food and Drug Administration (FDA). It has been gradually recognized that GPCRs are of significance for tumorigenesis, but in-depth studies are still required to explore specific mechanisms. In this study, the role of GPCRs in hepatocellular carcinoma (HCC) was elucidated, and GPCR-related genes were employed for building a risk-score model for the prognosis and treatment efficacy prediction of HCC patients.

Methods

Patients' data on HCC were sourced from the Liver Hepatocellular Carcinoma-Japan (LIRI-JP) and The Cancer Genome Atlas (TCGA) databases, while GPCR-related genes were obtained from the Molecular Signatures Database (MSigDB). Univariant and multivariant Cox regression analyses, as well as least absolute shrinkage and selection operator (LASSO) were performed with the aim of identifying differentially expressed GPCR-related genes and grouping patients. Differential expression and functional enrichment analyses were performed; protein-protein interaction (PPI) mechanisms were explored; hub genes and micro ribonucleic acid (miRNA)-target gene regulatory networks were constructed. The tumor immune dysfunction and exclusion (TIDE) algorithm was utilized to evaluate immune infiltration levels and genetic variations. Sensitivity to immunotherapy and common antitumor drugs was predicted via the database Genomics of Drug Sensitivity in Cancer (GDSC).

Results

A GPCR-related risk score containing eight GPCR-related genes (atypical chemokine receptor 3 (ACKR3), C-C chemokine receptor type 3 (CCR3), CCR7, frizzled homolog 5 (FZD5), metabotropic glutamate receptor 8 (GRM8), hydroxycarboxylic acid receptor 1 (HCAR1), 5-hydroxytryptamine receptor 5A (HTR5A) and nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 6 (NLRP6)) was set up. In addition, patients were classified into groups with high and low risks. Patients in the high-risk group exhibited a worse prognosis but demonstrated a more favorable immunotherapy response rate compared with those in the low-risk group. Distinct sensitivity to chemotherapeutic drugs was observed. A clinical prediction model on the basis of GPCR-related risk scores was constructed. Areas under the curves (AUC) corresponding to one-, three- and five-year survival were 0.731, 0.765 and 0.731, respectively.

Conclusions

In this study, an efficient HCC prognostic prediction model was constructed by only GPCR-related genes, which are all potential targets for HCC treatment.

ACY-241, a histone deacetylase 6 inhibitor, suppresses the epithelial-mesenchymal transition in lung cancer cells by downregulating hypoxia-inducible factor-1 alpha

Hypoxia-inducible factor-1 alpha (HIF-1α) is a transcription factor activated under hypoxic conditions, and it plays a crucial role in cellular stress regulation. While HIF-1α activity is essential in normal tissues, its presence in the tumor microenvironment represents a significant risk factor as it can induce angiogenesis and confer resistance to anti-cancer drugs, thereby contributing to poor prognoses. Typically, HIF-1α undergoes rapid degradation in normoxic conditions via oxygen-dependent degradation mechanisms. However, certain cancer cells can express HIF-1α even under normoxia. In this study, we observed an inclination toward increased normoxic HIF-1α expression in cancer cell lines exhibiting increased HDAC6 expression, which prompted the hypothesis that HDAC6 may modulate HIF-1α stability in normoxic conditions. To prove this hypothesis, several cancer cells with relatively higher HIF-1α levels under normoxic conditions were treated with ACY-241, a selective HDAC6 inhibitor, and small interfering RNAs for HDAC6 knockdown. Our data revealed a significant reduction in HIF-1α expression upon HDAC6 inhibition. Moreover, the downregulation of HIF-1α under normoxic conditions decreased zinc finger E-box-binding homeobox 1 expression and increased E-cadherin levels in lung cancer H1975 cells, consequently suppressing cell invasion and migration. ACY-241 treatment also demonstrated an inhibitory effect on cell invasion and migration by reducing HIF-1α level. This study confirms that HDAC6 knockdown and ACY-241 treatment effectively decrease HIF-1α expression under normoxia, thereby suppressing the epithelial-mesenchymal transition. These findings highlight the potential of selective HDAC6 inhibition as an innovative therapeutic strategy for lung cancer.

Trichostatin a inhibits expression of the human SLC2A5 gene via SNAI1/SNAI2 transcription factors and sensitizes colon cancer cells to platinum compounds

GLUT5, a key protein encoded by the SLC2A5 gene, is involved in the uptake of fructose from the intestine. Currently, with the increased consumption of this sugar and the associated increased incidence of obesity, diabetes and cancer, GLUT5 may represent an important molecular target in the prevention and treatment of these diseases. Here, we demonstrate that overexpression of the SNAI1 and SNAI2 transcription factors in cells expressing high levels of SLC2A5 mRNA reduced SLC2A5 gene expression. Furthermore, a histone deacetylase inhibitor, trichostatin A, which induces SNAI1 and SNAI2 expression, inhibits SLC2A5/GLUT5 expression and sensitizes colon cancer cells to cisplatin and oxaliplatin. This finding might have potential relevance for the development of therapeutic treatments aimed at modulating fructose transport or genes involved in this process for use with certain cancers.

The Multi-Functional Roles of CCR7 in Human Immunology and as a Promising Therapeutic Target for Cancer Therapeutics

An important hallmark of the human immune system is to provide adaptive immunity against pathogens but tolerance toward self-antigens. The CC-chemokine receptor 7 (CCR7) provides a significant contribution in guiding cells to and within lymphoid organs and is important for acquiring immunity and tolerance. The CCR7 holds great importance in establishing thymic architecture and function and naïve and regulatory T-cell homing in the lymph nodes. Similarly, the receptor is a key regulator in cancer cell migration and the movement of dendritic cells. This makes the CCR7 an important receptor as a drug and prognostic marker. In this review, we discussed several biological roles of the CCR7 and its importance as a drug and prognostic marker.

Secretome of senescent hepatoma cells modulate immune cell fate by macrophage polarization and neutrophil extracellular traps formation

Presence of dysfunctional senescent hepatocytes is a hallmark feature of liver cirrhosis which finally culminates in liver cancer. We now report the presence of senescent hepatocytes (p21 and p53 positive) in the vicinity of infiltrated immune cells in hepatocellular carcinoma tissue specimens by immunohistochemistry. Hence, we evaluated in vitro, the relevance of senescent hepatoma cells in altering the fate of monocytes and neutrophils by assaying for macrophage polarization and extracellular trap (NETs) formation, respectively. Premature senescence was induced in hepatoma cells (HepG2 and Huh7 cells) by treating cells with doxorubicin. Senescent hepatoma cells showed strong inflammatory phenotype with induced expression of cytokines (IL1β, IL6, IL8 and IL13) as evaluated by flow cytometry. The senescent secretome from hepatoma cells when incubated with healthy monocytes caused it to differentiate predominantly towards M2 fate (CD80^low CD86^low CD163^high CD206^high) when analysed by flow cytometry. This was corroborated by the finding in clinical samples where human hepatocellular carcinoma harbouring senescent hepatocytes showed presence of M2 macrophages, while M1 macrophages were predominant in non-tumorous region. Additionally, the senescent secretome from Huh7 cells enhanced the NETs formation, while HepG2 secretome had an inhibitory effect. In conclusion, the "pro-inflammatory" senescent secretome drives non-inflammatory type M2 macrophage polarization and modulated neutrophil traps which in turn can influence the tumor microenvironment.

New Insights of CCR7 Signaling in Dendritic Cell Migration and Inflammatory Diseases

CCR7, collaborated with its ligands CCL19 and CCL21, controls extensive migratory events in the immune system. CCR7-bearing dendritic cells can swarm into T-cell zones in lymph nodes, initiating the antigen presentation and T-cell response. Abnormal expression of CCR7 in dendritic cells will cause a series of inflammatory diseases due to the chaotic dendritic cell trafficking. In this review, we take an in-depth look at the structural–functional domains of CCR7 and CCR7-bearing dendritic cell trajectory to lymph nodes. Then, we summarize the regulatory network of CCR7, including transcriptional regulation, translational and posttranslational regulation, internalization, desensitization, and recycling. Furthermore, the potential strategies of targeting the CCR7 network to regulate dendritic cell migration and to deal with inflammatory diseases are integrated, which not only emphasizes the possibility of CCR7 to be a potential target of immunotherapy but also has an implication on the homing of dendritic cells to benefit inflammatory diseases.

Peritumoral Tertiary Lymphoid Structures Correlate With Protective Immunity and Improved Prognosis in Patients With Hepatocellular Carcinoma

The existence of intratumoral tertiary lymphoid structure (iTLS) has been reported to correlative with favorable clinical outcomes for patients with hepatocellular carcinoma (HCC). However, little is known about the role of peritumoral TLS (pTLS). This study aimed to investigate the prognostic role of pTLS either alone or jointly with iTLS and the potential association with local immune response in HCC. The formation and cellular composition of TLS was evaluated by hematoxylin & eosin and immunohistochemistry. Evaluation of tumor-infiltrating immune cells and formation of germinal center (GC) inside TLS was performed by immunohistochemistry. The gene expression profiles were analyzed by real-time PCR. In a total of 360 patients from two independent cohorts, the pTLS was identified in most, whereas iTLS could be observed in only approximately 30% of HCC specimens. Patients with high pTLS densities were associated with improved outcomes, those present with characteristic morphology of GC, particularly, showing an even better prognosis. The combination of pTLS and iTLS allowed the identification of patients with best prognosis. Tumors with high pTLS density showed significantly increased expression of Th1-, Th17- and immune suppression-related genes, as well as significantly higher infiltration of CD3+, CD8+ and CD20+ cells and lower infiltration of FOXP3+, CD68+ and PD1+ cells. Conclusively, we provide evidence that pTLS is associated with intratumoral immune infiltration, highlighting the dynamic interplay between pTLS and immune cells recruitment. High pTLS density links to a tumor microenvironment with an active immune reaction and improved patient survival and represents a promising prognostic biomarker for HCC.

Identification and immunoprofiling of key prognostic genes in the tumor microenvironment of hepatocellular carcinoma

Tumor microenvironment (TME) is involved in the occurrence and development of hepatocellular carcinoma (HCC), and immune cells in the TME have been implicated in its progression and treatment. However, the association of genes involved in the TME with HCC prognosis remains unclear. Thus, in this study, we obtained transcriptomic and clinicopathological data of patients with HCC from The Cancer Genome Atlas to identify key genes in TME associated with HCC prognosis. Stromal and immune cell scores were calculated using the ESTIMATE method, and differentially expressed genes (DEGs) were determined. We identified 830 DEGs, which were further subjected to survival analyses and functional enrichment analysis. Next, we identified prognostic TME-associated DEGs, established a protein-protein interaction (PPI) network, and performed Cox analysis.Consequently, four key prognostic genes (CXCL5, CXCL8, IL18RAP, and TREM2) associated with TME, were identified, in which CXCL5 and IL18RAP may be potential independent prognostic factors. Age, clinical stage, N stage, and risk score were also determined as significant prognostic variables. CIBERSORT was used to predict the constitution and relative content of the immune cells, wherein M0 macrophages were the most closely related to the key genes. In conclusion, CXCL5, CXCL8, IL18RAP, and TREM2 were associated with HCC prognosis and were important for immune cell invasion into the TME. Additionally, IL18RAP expression may contribute toward favorable prognosis in patients with HCC. Consequently, these genes may serve as potential biomarkers and immunotherapeutic targets for HCC.

Role of chemokines in hepatocellular carcinoma (Review)

Hepatocellular carcinoma (HCC) is a prevalent malignant tumor worldwide, with an unsatisfactory prognosis, although treatments are improving. One of the main challenges for the treatment of HCC is the prevention or management of recurrence and metastasis of HCC. It has been found that chemokines and their receptors serve a pivotal role in HCC progression. In the present review, the literature on the multifactorial roles of exosomes in HCC from PubMed, Cochrane library and Embase were obtained, with a specific focus on the functions and mechanisms of chemokines in HCC. To date, >50 chemokines have been found, which can be divided into four families: CXC, CX3C, CC and XC, according to the different positions of the conserved N‑terminal cysteine residues. Chemokines are involved in the inflammatory response, tumor immune response, proliferation, invasion and metastasis via modulation of various signaling pathways. Thus, chemokines and their receptors directly or indirectly shape the tumor cell microenvironment, and regulate the biological behavior of the tumor. In addition, the potential application of chemokines in chemotaxis of exosomes as drug vehicles is discussed. Exosomes containing chemokines or expressing receptors for chemokines may improve chemotaxis to HCC and may thus be exploited for targeted drug delivery.

CCR7 as a therapeutic target in Cancer

The CCR7 chemokine axis is comprised of chemokine ligand 21 (CCL21) and chemokine ligand 19 (CCL19) acting on chemokine receptor 7 (CCR7). This axis plays two important but apparently opposing roles in cancer. On the one hand, this axis is significantly engaged in the trafficking of a number of effecter cells involved in mounting an immune response to a growing tumour. This suggests therapeutic strategies which involve potentiation of this axis can be used to combat the spread of cancer. On the other hand, the CCR7 axis plays a significant role in controlling the migration of tumour cells towards the lymphatic system and metastasis and can thus contribute to the expansion of cancer. This implies that therapeutic strategies which involve decreasing signaling through the CCR7 axis would have a beneficial effect in preventing dissemination of cancer. This dichotomy has partly been the reason why this axis has not yet been exploited, as other chemokine axes have, as a therapeutic target in cancer. Recent report of a crystal structure for CCR7 provides opportunities to exploit this axis in developing new cancer therapies. However, it remains unclear which of these two strategies, potentiation or antagonism of the CCR7 axis, is more appropriate for cancer therapy. This review brings together the evidence supporting both roles of the CCR7 axis in cancer and examines the future potential of each of the two different therapeutic approaches involving the CCR7 axis in cancer.

Tackle Epithelial-Mesenchymal Transition With Epigenetic Drugs in Cancer

Epithelial-mesenchymal Transition (EMT) is a de-differentiation process in which epithelial cells lose their epithelial properties to acquire mesenchymal features. EMT is essential for embryogenesis and wound healing but is aberrantly activated in pathological conditions like fibrosis and cancer. Tumor-associated EMT contributes to cancer cell initiation, invasion, metastasis, drug resistance and recurrence. This dynamic and reversible event is governed by EMT-transcription factors (EMT-TFs) with epigenetic complexes. In this review, we discuss recent advances regarding the mechanisms that modulate EMT in the context of epigenetic regulation, with emphasis on epigenetic drugs, such as DNA demethylating reagents, inhibitors of histone modifiers and non-coding RNA medication. Therapeutic contributions that improve epigenetic regulation of EMT will translate the clinical manifestation as treating cancer progression more efficiently.

Metformin Combined with 4SC-202 Inhibited the Migration and Invasion of OSCC via STAT3/TWIST1

Background

Oral squamous cell carcinoma (OSCC), the most common epithelial malignant neoplasm in the head and neck, characterizes with local infiltration and metastasis of lymph nodes. The five-year survival rate of OSCC remains low despite the advances in clinical methods. Thus, it is necessary to develop a new effective therapeutic scheme for OSCC. Our previous results showed that metformin and 4SC-202 synergistically promoted the intrinsic apoptosis of OSCC in vitro and in vivo, but the effects on invasion and migration remained unclear.

Methods

Human OSCC cell lines HSC6 and CAL33 were cultured with metformin (16 mM) or/and 4SC-202 (0.4 μM) for 72 h. STAT3 inhibitor S31-201 was applied at concentration of 60 μM for 48 h. Wound-healing assays and transwell assays were used to determine the invasion and migration ability of OSCC. qRT-PCR and Western blot were performed to detect mRNA levels and protein levels.

Results

Metformin or/and 4SC-202 suppressed the migration and invasion of OSCC cells. Importantly, the expression of TWIST1 was suppressed by metformin and 4SC-202, while the invasion and migration inhibitory effects of metformin and 4SC-202 were countered by the overexpression of TWIST1. In addition, the phosphorylation level of STAT3 decreased after the administration of metformin or/and 4SC-202. Furthermore, inhibition of STAT3 by S31-201 suppressed the expression of TWIST1 and led to a decline in migration and invasion of OSCC, while overexpression of TWIST1 attenuated these effects.

Conclusion

Metformin and 4SC-202 suppressed the invasion and migration of OSCC through inhibition of STAT3/TWIST1, and this scheme can serve as a novel therapeutic strategy for OSCC.

Histone deacetylase inhibitors promote epithelial-mesenchymal transition in Hepatocellular Carcinoma via AMPK-FOXO1-ULK1 signaling axis-mediated autophagy

Hepatocellular carcinoma (HCC) is the third most frequent cause of cancer-related deaths globally because of high metastasis and recurrence rates. Elucidating the molecular mechanisms of HCC recurrence and metastasis and developing effective targeted therapies are expected to improve patient survival. The promising anti-cancer agents for the treatment of hematological malignancies, histone deacetylase inhibitors (HDIs), have limited effects against epithelial cell-derived cancers, including HCC, the mechanisms involved have not been elucidated. Herein, we studied the molecular mechanisms underlying HDI-induced epithelial-mesenchymal transition (EMT) involving FOXO1-mediated autophagy. Methods: The biological functions of HDIs in combination with autophagy inhibitors were examined both in vitro and in vivo. Cell autophagy was assessed using the generation of mRFP-GFP-LC3-expressing cells and fluorescent LC3 puncta analysis, Western blotting, and electron microscopy. An orthotopic hepatoma model was established in mice for the in vivo experiments. Results: Our study provided novel mechanistic insights into HDI-induced EMT mediated by the autophagy AMPK-FOXO1-ULK1-Snail signaling axis. We demonstrated that autophagy served as a pro-metastasis mechanism in HDI-treated hepatoma cells. HDIs induced autophagy via a FOXO1-dependent pathway, and FOXO1 inhibition promoted HDI-mediated apoptosis in hepatoma cells. Thus, our findings provided novel insights into the molecular mechanisms underlying HDI-induced EMT involving FOXO1-mediated autophagy and demonstrated that a FOXO1 inhibitor exerted a synergistic effect with an HDI to inhibit cell growth and metastasis in vitro and in vivo. Conclusion: We demonstrated that HDIs triggers FOXO1-dependent autophagy, which ultimately promotes EMT, limiting the clinical outcome of HDI-based therapies. Our study suggests that the combination of an HDI and a FOXO1 inhibitor is an effective therapeutic strategy for the treatment of HCC.

Cell Surface Proteins in Hepatocellular Carcinoma: From Bench to Bedside

Cell surface proteins act as the go-between in carrying the information from the extracellular environment to the intracellular signaling proteins. However, these proteins are often deregulated in neoplastic diseases, including hepatocellular carcinoma. This review discusses several recent studies that have investigated the role of cell surface proteins in the occurrence and progression of HCC, highlighting the possibility to use them as biomarkers of the disease and/or targets for vaccines and therapeutics.

Mining TCGA Database for Tumor Microenvironment-Related Genes of Prognostic Value in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common and lethal malignancies. Recent studies reveal that tumor microenvironment (TME) components significantly affect HCC growth and progression, particularly the infiltrating stromal and immune cells. Thus, mining of TME-related biomarkers is crucial to improve the survival of patients with HCC. Public access of The Cancer Genome Atlas (TCGA) database allows convenient performance of gene expression-based analysis of big data, which contributes to the exploration of potential association between genes and prognosis of a variety of malignancies, including HCC. The "Estimation of STromal and Immune cells in MAlignant Tumors using Expression data" algorithm renders the quantification of the stromal and immune components in TME possible by calculating the stromal and immune scores. Differentially expressed genes (DEGs) were screened by dividing the HCC cohort of TCGA database into high- and low-score groups according to stromal and immune scores. Further analyses of functional enrichment and protein-protein interaction networks show that the DEGs are mainly involved in immune response, cell adhesion, and extracellular matrix. Finally, seven DEGs have significant association with HCC poor outcomes. These genes contain FABP3, GALNT5, GPR84, ITGB6, MYEOV, PLEKHS1, and STRA6 and may be candidate biomarkers for HCC prognosis.

Pyrroline-5-Carboxylate Reductase 1 Accelerates the Migration and Invasion of Nonsmall Cell Lung Cancer In Vitro

Background: Pyrroline-5-carboxylate reductase 1 (PYCR1) is involved in tumor progression, for instance, breast cancer and prostate cancer. However, its role in tumor metastasis, especially in nonsmall cell lung cancer (NSCLC), is still elusive. Materials and Methods: The messenger RNA (mRNA) expression of PYCR1 between NSCLC and normal lung specimens was compared using Oncomine database. The endogenous PYCR1 expressions in NSCLC cell lines 95C and H1299 were knocked down by lentiviral-mediated delivery of short hairpin RNA (shRNA). Then the effects of PYCR1 on the migration and invasion of NSCLC cells were studied by wound healing assay and transwell assay. Results: PYCR1 mRNA expression was significantly higher in NSCLC specimens than that in normal lung tissues. Depletion of PYCR1 in NSCLC cell significantly repressed the cell migration and invasion. Moreover, depletion of PYCR1 influenced the expression of epithelial-mesenchymal transition molecules E-cadherin, Vimentin, N-cadherin, and Snail1. Conclusions: Our data suggested that PYCR1 plays a positive role in NSCLC metastasis in vitro and might be a promising target for treating NSCLC.

Up-regulation of TIF1γ by valproic acid inhibits the epithelial mesenchymal transition in prostate carcinoma through TGF-β/Smad signaling pathway

Valproic acid (VPA), one of the histone deacetylase inhibitors, can suppress prostate cancer (PCa) cells epithelial mesenchymal transition (EMT). Transcriptional intermediary factor 1γ (TIF1γ) which is a vital protein molecule that possesses ubiquitination enzyme activity, can mediate TGF-β induced EMT. We aimed to investigate the detailed mechanism between VPA and EMT occurrence in PCa cells to clarify the potential mechanism of TIF1γ involved. In our vitro experiments, we first investigated the effect of VPA on the expression TIF1γ. After TIF1γ was knockdown or overexpressed by related lentivirus, EMT of PCa cells were assessed. When TIF1γ knockdown or overexpress stable cell line were established, cells were treated with additional VPA, EMT index were detected and functional experiments were also conducted to confirm whether VPA inhibited EMT of PCa cells via TIF1γ. The mono-ubiquitination of Smad4 was analyzed simultaneously. In vivo, mice were facilitated with PC3 cells or TIF1γ related knockdown or overexpress virus transfected PC3 cells with or without VPA administration. Results showed that in vitro VPA can increase the expression of TIF1γ and also induce the increase expression of E-cadherin, and the decrease of N-cadherin and vimentin. Knocking down of TIF1γ can effectively block the effect of VPA on EMT and metastasis while overexpression of TIF1γ can strengthen its role. In vivo VPA also showed its anti-growth effect including tumor growth and EMT mediated by TIF1γ coincide with in vitro experiments. In conclusion, VPA inhibits the EMT in PCa cells via up-regulating the expression of TIF1γ and the mono-ubiquitination Smad4. VPA could serve as a promising agent in PCa treatment, with new strategies based on its diverse effects on posttranscriptional regulation.

Histone Deacetylase Inhibitors and Phenotypical Transformation of Cancer Cells

Histone deacetylase inhibitors (HDIs) are a group of potent epigenetic drugs which have been investigated for their therapeutic potential in various clinical disorders, including hematological malignancies and solid tumors. Currently, several HDIs are already in clinical use and many more are on clinical trials. HDIs have shown efficacy to inhibit initiation and progression of cancer cells. Nevertheless, both pro-invasive and anti-invasive activities of HDIs have been reported, questioning their impact in carcinogenesis. The aim of this review is to compile and discuss the most recent findings on the effect of HDIs on the epithelial-mesenchymal transition (EMT) process in human cancers. We have summarized the impact of HDIs on epithelial (E-cadherin, β-catenin) and mesenchymal (N-cadherin, vimentin) markers, EMT activators (TWIST, SNAIL, SLUG, SMAD, ZEB), as well as morphology, migration and invasion potential of cancer cells. We further discuss the use of HDIs as monotherapy or in combination with existing or novel anti-neoplastic drugs in relation to changes in EMT.