Contribution of FPR and TLR9 to hypoxia-induced chemoresistance of ovarian cancer cells

The small molecule peptide ANXA114-26 inhibits ovarian cancer cell proliferation and reverses cisplatin resistance by binding to the formyl peptide receptors receptor

Chemo-resistance in ovarian cancer is currently a major obstacle to the treatment and recovery of ovarian cancer. Therefore, identifying factors associated with chemo-resistance in ovarian cancer may reverse chemo-sensitization. Using isobaric tags for relative and absolute quantitation (ITRAQ) technology, we found a small molecule peptide with annexin 1 (ANXA1) as a precursor protein. Then, we explored the effects and mechanisms of this small molecule peptide on the proliferation, apoptosis, and drug resistance of ovarian cancer resistant cells through CCK-8, EdU cell proliferation assay, Annexin V-FITC/PI assay, Western blot,qRT-PCR. ANXA114-26 was highly expressed in the serums of sensitive patients. ANXA114-26 promoted apoptosis of ovarian cancer cells and increased the sensitization of ovarian cancer cells to cisplatin. The ANXA114-26 and ANXA1 competitively bind formyl peptide receptors (FPR). ANXA114-26 decreased multidrug resistance-associated protein 1 (MRP1) expression in ovarian cancer cells through the FPR/Cyclin D1/NF-ĸBp65 pathway. We found a peptide derived named ANXA114-26 in the serum of ovarian cancer patients. It can reduce ovarian cancer cell proliferation and reduce MRP1 expression through the FPR/Cyclin D1/NF-ĸBp65 pathway.

The emerging roles of TLR and cGAS signaling in tumorigenesis and progression of ovarian cancer

Ovarian cancer is fatal to women and has a high mortality rate. Although on-going efforts are never stopped in identifying diagnostic and intervention strategies, the disease is so far unable to be well managed. The most important reason for this is the complexity of pathogenesis for OC, and therefore, uncovering the essential molecular biomarkers accompanied with OC progression takes the privilege for OC remission. Inflammation has been reported to participate in the initiation and progression of OC. Both microenvironmental and tumor cell intrinsic inflammatory signals contribute to the malignancy of OC. Inflammation responses can be triggered by various kinds of stimulus, including endogenous damages and exogenous pathogens, which are initially recognized and orchestrated by a series of innate immune system related receptors, especially Toll like receptors, and cyclic GMP-AMP synthase. In this review, we will discuss the roles of innate immune system related receptors, including TLRs and cGAS, and responses both intrinsic and exogenetic in the development and treatment of OC.

Identifying Key Lysosome-Related Genes Associated with Drug-Resistant Breast Cancer Using Computational and Systems Biology Approach

Background

Drug resistance in breast cancer is an unsolved problem in treating patients. It has been recently discussed that lysosomes contribute to the invasion and angiogenesis of cancer cells. There is evidence that lysosomes can also cause multi-drug resistance. We analyzed this emerging concept in breast cancer through computational and systems biology approaches.

Objectives

We aimed to identify the key lysosome-related genes associated with drug-resistant breast cancer.

Methods

All genes contributing to the structure and function of lysosomes were inquired through the Human Lysosome Gene Database. The prioritized top 51 genes from the provided lists of Endeavour, ToppGene, and GPSy as prioritization tools were selected. All lysosomal genes and 12 breast cancer-related genes aligned to identify the most similar genes to breast cancer-related genes. Different centralities were applied to score each human protein to calculate the most central lysosomal genes in the human protein-protein interaction (PPI) network. Common genes were extracted from the results of the mentioned methods as a selected gene set. For Gene Ontology enrichment, the selected gene set was analyzed by WebGestalt, DAVID, and KOBAS. The PPI network was constructed via the STRING database. The PPI network was analyzed utilizing Cytoscape for topology network interaction and CytoHubba to extract hub genes.

Results

Based on biological studies, literature reviews, and comparing all mentioned analyzing methods, six genes were introduced as essential in breast cancer. This computational approach to all lysosome-related genes suggested that candidate genes include PRF1, TLR9, CLTC, GJA1, AP3B1, and RPTOR. The analyses of these six genes suggest that they may have a crucial role in breast cancer development, which has rarely been evaluated. These genes have a potential therapeutic implication for new drug discovery for chemo-resistant breast cancer.

Conclusions

The present work focused on all the functional and structural lysosome-related genes associated with breast cancer. It revealed the top six lysosome hub genes that might serve as therapeutic targets in drug-resistant breast cancer. Since these genes play a pivotal role in the structure and function of lysosomes, targeting them can effectively overcome drug resistance.

Hypoxia-Mediated Decrease of Ovarian Cancer Cells Reaction to Treatment: Significance for Chemo- and Immunotherapies

Hypoxia, a common factor ruling the microenvironment composition, leads to tumor progression. In this hypoxic context, cytokines and cells cooperate to favor cancer development and metastasis. Tumor hypoxia is heterogeneously distributed. Oxygen gradients depend on the vicinity, functionality of blood vessels, and oxygen ability to diffuse into surrounding tissues. Thus, the vasculature state modulates the microenvironment of the tumor cells. Cells sense and react to small variations in oxygen tension, which explains the lack of tumor cells’ unicity in their reaction to drugs. Ovarian cancers are highly hypoxia-dependent, ascites worsening the access to oxygen, in their reactions to both chemotherapy and new immunotherapy. Consequently, hypoxia affects the results of immunotherapy, and is thus, crucial for the design of treatments. Controlling key immunosuppressive factors and receptors, as well as immune checkpoint molecule expression on tumor, immune and stromal cells, hypoxia induces immunosuppression. Consequently, new approaches to alleviate hypoxia in the tumor microenvironment bring promises for ovarian cancer immunotherapeutic strategies. This review focuses on the effects of hypoxia in the microenvironment and its consequences on tumor treatments. This opens the way to innovative combined treatments to the advantage of immunotherapy outcome in ovarian cancers.

Inhibition of formyl peptide receptor 1 activity suppresses tumorigenicity in vivo and attenuates the invasion and migration of lung adenocarcinoma cells under hypoxic conditions in vitro

Background

Tumor hypoxia has been widely reported to promote metastasis. However, the molecular mechanisms underlying metastasis-associated hypoxia remain unclear. Formyl peptide receptor 1 (FPR1) has been reported to be highly expressed under hypoxic conditions. This study aimed to explore the role of FPR1 in tumor cells under hypoxic conditions.

Methods

The expressions of FPR1 and hypoxia-inducible factor 1α (HIF-1α) in A549 cells under hypoxic conditions were detected using western blot. The expression of FPR1 in A549 cells under hypoxic conditions was suppressed using the FPR1 antagonist Boc2. Wound-healing and Transwell assays were performed to investigate the migration and invasion of cells. Furthermore, the tumorigenicity of A549 cells was evaluated by constructing a hypoxic mouse model of lung adenocarcinoma. The expression levels of HIF-1α and FPR1 in tumors were measured by real-time polymerase chain reaction (PCR) and western blot.

Results

The expression levels of FPR1 and HIF-1α increased in a time-dependent manner after exposure to hypoxic conditions. Wound-healing and Transwell assays showed that hypoxia promoted the migration and invasion abilities of A549 cells, whereas downregulation of FPR1 blocked the effects of hypoxia on A549 cells. Our in vivo results demonstrated that the tumor volumes and weights of mice exposed to hypoxic conditions were significantly higher than those of untreated mice. Furthermore, the downregulation of FPR1 blocked the effects of hypoxia in the mice. Meanwhile, the expressions of HIF-1α and FPR1 at the protein and mRNA levels were increased after hypoxic exposure, whereas FPR1 antagonist Boc2 suppressed the effect of hypoxia on the expression of FPR1.

Conclusions

Our results suggest that FPR1 could be a therapeutic target for suppressing the invasion and tumorigenicity of lung adenocarcinoma cells.

Application of small molecule FPR1 antagonists in the treatment of cancers

The formylpeptide receptor-1 (FPR1) is a member of the chemotactic GPCR-7TM formyl peptide receptor family, whose principle function is in trafficking of various leukocytes into sites of bacterial infection and inflammation. More recently, FPR1 has been shown to be expressed in different types of cancer and in this context, plays a significant role in their expansion, resistance and recurrence. ICT12035 is a selective and potent (30 nM in calcium mobilisation assay) small molecule FPR1 antagonist. Here, we demonstrate the efficacy of ICT12035, in a number of 2D and 3D proliferation and invasion in vitro assays and an in vivo model. Our results demonstrate that targeting FPR1 by a selective small molecule antagonist, such as ICT12035, can provide a new avenue for the treatment of cancers.

TLR9 induces colitis-associated colorectal carcinogenesis by regulating NF-κB expression levels

Chronic colorectal inflammation has been associated with colorectal cancer (CRC); however, its exact molecular mechanisms remain unclear. The present study aimed to investigate the effect of Toll-like receptor 9 (TLR9) on the development of colitis-associated CRC (CAC) through its regulation of the NF-κB signaling pathway. By using a CAC mouse model and immunohistochemistry, the present study discovered that the protein expression levels of TLR9 were gradually upregulated during the development of CRC. In addition, the expression levels of TLR9 were revealed to be positively correlated with NF-κB and Ki67 expression levels. In vitro, inhibiting TLR9 expression levels using chloroquine decreased the cell viability, proliferation and migration of the CRC cell line HT29, and further experiments indicated that this may occur through downregulating the expression levels of NF-κB, proliferating cell nuclear antigen and Bcl-xl. In conclusion, the findings of the present study suggested that TLR9 may serve an important role in the development of CAC by regulating NF-κB signaling.

Tumor microenvironment and epithelial mesenchymal transition as targets to overcome tumor multidrug resistance

It is well established that multifactorial drug resistance hinders successful cancer treatment. Tumor cell interactions with the tumor microenvironment (TME) are crucial in epithelial-mesenchymal transition (EMT) and multidrug resistance (MDR). TME-induced factors secreted by cancer cells and cancer-associated fibroblasts (CAFs) create an inflammatory microenvironment by recruiting immune cells. CD11b+/Gr-1+ myeloid-derived suppressor cells (MDSCs) and inflammatory tumor associated macrophages (TAMs) are main immune cell types which further enhance chronic inflammation. Chronic inflammation nurtures tumor-initiating/cancer stem-like cells (CSCs), induces both EMT and MDR leading to tumor relapses. Pro-thrombotic microenvironment created by inflammatory cytokines and chemokines from TAMs, MDSCs and CAFs is also involved in EMT and MDR. MDSCs are the most common mediators of immunosuppression and are also involved in resistance to targeted therapies, e.g. BRAF inhibitors and oncolytic viruses-based therapies. Expansion of both cancer and stroma cells causes hypoxia by hypoxia-inducible transcription factors (e.g. HIF-1α) resulting in drug resistance. TME factors induce the expression of transcriptional EMT factors, MDR and metabolic adaptation of cancer cells. Promoters of several ATP-binding cassette (ABC) transporter genes contain binding sites for canonical EMT transcription factors, e.g. ZEB, TWIST and SNAIL. Changes in glycolysis, oxidative phosphorylation and autophagy during EMT also promote MDR. Conclusively, EMT signaling simultaneously increases MDR. Owing to the multifactorial nature of MDR, targeting one mechanism seems to be non-sufficient to overcome resistance. Targeting inflammatory processes by immune modulatory compounds such as mTOR inhibitors, demethylating agents, low-dosed histone deacetylase inhibitors may decrease MDR. Targeting EMT and metabolic adaptation by small molecular inhibitors might also reverse MDR. In this review, we summarize evidence for TME components as causative factors of EMT and anticancer drug resistance.