Predictive value of TLR7 polymorphism for cetuximab-based chemotherapy in patients with metastatic colorectal cancer

Genetic association and functional implications of TLR4 rs1927914 polymorphism on colon cancer risk

BACKGROUND

Colon cancer remains a major health concern worldwide, with genetic factors playing a crucial role in its development. Toll-like receptors (TLRs) has been implicated in various cancers, but their role in colon cancer is not well understood. This study aims to identify functional polymorphisms in the promoter and 3'UTR regions of TLRs and evaluate their association with colon cancer susceptibility.

METHODS

We conducted a case-control study involving 410 colon cancer patients and 410 healthy controls from the Chinese population. Genotyping of polymorphisms in TLR3, TLR4, TLR5 and TLR7 was performed using PCR-RFLP and TaqMan MGB probes. Using logistic regression analysis, we evaluated the association of TLRs polymorphisms and the susceptibility to colon cancer. To understand the biological implications of the TLR4 rs1927914 polymorphism, we conducted functional assays, including luciferase reporter assay and electrophoretic mobility shift assay (EMSA).

RESULTS

Our results demonstrated that the G-allele of the TLR4 rs1927914 polymorphism is significantly associated with a decreased risk of colon cancer (OR = 0.68, 95%CI = 0.50-0.91). Stratified analysis showed that TLR4 rs1927914 AG or GG genotype contributed to a decreased risk of colon cancer among younger individuals (OR = 0.52, 95%CI = 0.34-0.81), males (OR = 0.58, 95%CI = 0.38-0.87), non-smokers (OR = 0.58, 95%CI = 0.41-0.83) and non-drinker with OR (95%CI) of 0.66 (0.46-0.93). Functional assays demonstrated that in HCT116 and LOVO colon cancer cells, the luciferase activity driven by the TLR4 promoter with the rs1927914A allele was 5.43 and 2.07 times higher, respectively, compared to that driven by the promoter containing the rs1927914G allele. Electrophoretic mobility shift assay (EMSA) results indicated that the rs1927914G allele enhanced transcription factor binding. Using the transcription factor prediction tool, we found that the G allele facilitates binding of the repressive transcription factor Oct1, while the A allele does not.

CONCLUSION

The TLR4 rs1927914 polymorphism influence the susceptibility to colon cancer, with the G allele offering a protective effect through modulation of gene expression. These insights enhance our understanding of the genetic determinants of colon cancer risk and highlight TLR4 as a promising target for cancer prevention strategies.

T7 peptide-decorated exosome-based nanocarrier system for delivery of Galectin-9 siRNA to stimulate macrophage repolarization in glioblastoma

PURPOSE

Exosomes are nano-vesicular carriers capable of delivering cargoes for intercellular communication, which holds potential as biocompatible and high efficiency systems for drug delivery. In this study, we evaluated the potential effect of T7 peptide-decorated exosome-loaded Galectin-9 siRNA (T7-Exo/siGalectin-9) in the M1 polarization of macrophages and immunosuppression of glioblastoma (GBM).

METHODS

Differentially expressed genes in GBM were in silico predicted and then experimentally verified. Galectin-9 was knocked down by siRNA to assess its role in tumor-bearing mice. T7 peptide-decorated exosomes (derived from human embryonic kidney [HEK]-293T cells) targeting GBM were prepared, and loaded with Galectin-9 siRNA by electroporation to prepare nanoformulations (T7-Exo/siGalectin-9). The role of T7-Exo/siGalectin-9 in CD8+ T cell cytotoxicity to target GBM cells and polarization of macrophages was evaluated after artificial modulation of Galectin-9 expression. Anti-tumor effects of T7-Exo/siGalectin-9 were elucidated in vitro and in vivo.

RESULTS

Galectin-9 was highly expressed in GBM tissues and cell lines. The siRNA-mediated knockdown of Galectin-9 repressed the growth of xenografts of GBM cells in C57BL/6 mice and activated immune response in the tumor microenvironment. T7-Exo/siGalectin-9 effectively delivered siGalectin-9 to GBM cells. T7-Exo/siGalectin-9 contributed to activation of the TLR7-IRF5 pathway, which polarized macrophages to M1 phenotype. By this mechanism, phagocytosis of GBM cells by macrophages was increased, the anti-tumor effect of CD8+ T cells was enhanced and the inflammatory responses were suppressed.

CONCLUSION

Overall, T7-Exo/siGalectin-9 promotes macrophage repolarization and restricts the immunosuppression of GBM, thus providing novel insights into and drug delivery system of immunotherapy for GBM.

Targeting toll-like receptor 7/8 for immunotherapy: recent advances and prospectives

Toll-like receptors (TLRs) are a large family of proteins that are expressed in immune cells and various tumor cells. TLR7/8 are located in the intracellular endosomes, participate in tumor immune surveillance and play different roles in tumor growth. Activation of TLRs 7 and 8 triggers induction of a Th1 type innate immune response in the highly sophisticated process of innate immunity signaling with the recent research advances involving the small molecule activation of TLR 7 and 8. The wide range of expression and clinical significance of TLR7/TLR8 in different kinds of cancers have been extensively explored. TLR7/TLR8 can be used as novel diagnostic biomarkers, progression and prognostic indicators, and immunotherapeutic targets for various tumors. Although the mechanism of action of TLR7/8 in cancer immunotherapy is still incomplete, TLRs on T cells are involved in the regulation of T cell function and serve as co-stimulatory molecules and activate T cell immunity. TLR agonists can activate T cell-mediated antitumor responses with both innate and adaptive immune responses to improve tumor therapy. Recently, novel drugs of TLR7 or TLR8 agonists with different scaffolds have been developed. These agonists lead to the induction of certain cytokines and chemokines that can be applied to the treatment of some diseases and can be used as good adjutants for vaccines. Furthermore, TLR7/8 agonists as potential therapeutics for tumor-targeted immunotherapy have been developed. In this review, we summarize the recent advances in the development of immunotherapy strategies targeting TLR7/8 in patients with various cancers and chronic hepatitis B.

Pharmacogenetics Role of Genetic Variants in Immune-Related Factors: A Systematic Review Focusing on mCRC

Pharmacogenetics plays a key role in personalized cancer treatment. Currently, the clinically available pharmacogenetic markers for metastatic colorectal cancer (mCRC) are in genes related to drug metabolism, such as DPYD for fluoropyrimidines and UGT1A1 for irinotecan. Recently, the impact of host variability in inflammatory and immune-response genes on treatment response has gained considerable attention, opening innovative perspectives for optimizing tailored mCRC therapy. A literature review was performed on the predictive role of immune-related germline genetic biomarkers on pharmacological outcomes in patients with mCRC. Particularly, that for efficacy and toxicity was reported and the potential role for clinical management of patients was discussed. Most of the available data regard therapy effectiveness, while the impact on toxicity remains limited. Several studies focused on the effects of polymorphisms in genes related to antibody-dependent cellular cytotoxicity (FCGR2A, FCGR3A) and yielded promising but inconclusive results on cetuximab efficacy. The remaining published data are sparse and mainly hypothesis-generating but suggest potentially interesting topics for future pharmacogenetic studies, including innovative gene-drug interactions in a clinical context. Besides the tumor immune escape pathway, genetic markers belonging to cytokines/interleukins (IL-8 and its receptors) and angiogenic mediators (IGF1) seem to be the best investigated and hopefully most promising to be translated into clinical practice after validation.

Biological roles of toll-like receptors and gut microbiota in colorectal cancer

Colorectal cancer (CRC) is one of the most considerably common malignancies of the alimentary system, with high mortality and incidence rates.  The present study suggested that the occurrence of CRC is closely related to bacteria, as the large intestine is a gathering place for human micro-organisms. However, the nosogenesis of bacteria leading to tumorigenesis is still obscure. Recently, many studies have reported that toll-like receptors and their related molecular pathways are involved in the process of gut micro-organisms generating CRC. Gut micro-organisms can promote or inhibit the development of CRC via binding to special toll-like receptors. In this paper, the authors review the relationship among toll-like receptors, gut micro-organisms and CRC in order to provide a reference for future tumor immunotherapy and targeted therapy.

Predicting drug response and toxicity in metastatic colorectal cancer: the role of germline markers

INTRODUCTION

Despite the introduction of targeted agents leading to therapeutic advances, clinical management of patients with metastatic colorectal cancer (mCRC) is still challenged by significant interindividual variability in treatment outcomes, both in terms of toxicity and therapy efficacy. The study of germline genetic variants could help to personalize and optimize therapeutic approaches in mCRC.

AREAS COVERED

A systematic review of pharmacogenetic studies in mCRC patients published on PubMed between 2011 and 2021, evaluating the role of germline variants as predictive markers of toxicity and efficacy of drugs currently approved for treatment of mCRC, was perfomed.

EXPERT OPINION

Despite the large amount of pharmacogenetic data published to date, only a few genetic markers (i.e., DPYD and UGT1A1 variants) reached the clinical practice, mainly to prevent the toxic effects of chemotherapy. The large heterogeneity of available studies represents the major limitation in comparing results and identifying potential markers for clinical use, the role of which remains exploratory in most cases. However, the available published findings are an important starting point for future investigations. They highlighted new promising pharmacogenetic markers within the network of inflammatory and immune response signaling. In addition, the emerging role of previously overlooked rare variants has been pointed out.

The interferon regulatory factor 6 promotes cisplatin sensitivity in colorectal cancer

Colorectal cancer (CRC) is one of the most common malignancies and causes of cancer-related mortality worldwide. Cell proliferation and tumor metastasis as well as chemoresistance are correlated with poor survival of CRC. The interferon regulatory factor 6 (IRF6) is functioned as a tumor suppressor gene in several cancers and is associated with risk of CRC. We explored the role of IRF6 in CRC in the present study. The protein expressions of IRF6 in human CRC tissues, normal para-carcinoma tissue and liver metastases from CRC were measured. Cell proliferation, chemotherapeutic sensitivity, cell apoptosis, migration and invasion including the related markers along with IRF6 expression were explored. Our results indicated that IRF6 expression in CRC and liver metastasis were lower than normal tissues, which were correlated positively with E-cadherin and negatively with Ki67 expression in CRC tissue. IRF6 promoted CRC cell sensitivity to cisplatin to suppress cell proliferation, migration and invasion as well as aggravate cell apoptosis. Our study suggested that IRF6 may enhance chemotherapeutic sensitivity of cisplatin mediated by affecting cell proliferation, migration and invasion along with apoptosis through regulating E-cadherin and Ki67, while the identified molecular mechanisms remain to be further explored.

High Tissue TLR5 Expression Predicts Better Outcomes in Colorectal Cancer Patients

BACKGROUND

Colorectal cancer (CRC), the third most common cancer globally, caused 881,000 cancer deaths in 2018. Toll-like receptors (TLRs), the primary sensors of pathogen-associated molecular patterns and damage-associated molecular patterns, activate innate and adaptive immune systems and participate in the development of an inflammatory tumor microenvironment. We aimed to explore the prognostic value of TLR3, TLR5, TLR7, and TLR9 tissue expressions in CRC patients.

METHODS

Using immunohistochemistry, we analyzed tissue microarray samples from 825 CRC patients who underwent surgery between 1982 and 2002 at the Department of Surgery, Helsinki University Hospital, Finland. After analyzing a pilot series of 205 tissue samples, we included only TLR5 and TLR7 in the remainder of the patient series. We evaluated the associations between TLR5 and TLR7 tissue expressions, clinicopathologic variables, and survival. Using the Kaplan-Meier method, we generated survival curves, determining significance using the log-rank test. Univariate and multivariate survival analyses relied on the Cox proportional hazards model.

RESULTS

The 5-year disease-specific survival was 55.9% among TLR5-negative (95% confidence interval [CI] 50.6-61.2%) and 61.9% (95% CI 56.6-67.2%; p = 0.011, log-rank test) among TLR5-positive patients. In the Cox multivariate survival analysis adjusted for age, sex, stage, location, and grade, positive TLR5 immunoexpression (hazard ratio [HR] 0.74; 95% CI 0.59-0.92; p = 0.007) served as an independent positive prognostic factor. TLR7 immunoexpression exhibited no prognostic value in the survival analysis across the entire cohort (HR 0.97; 95% CI 0.78-1.20; p = 0.754) nor in subgroup analyses.

CONCLUSIONS

We show for the first time that a high TLR5 tumor tissue expression associates with a better prognosis in CRC patients.

Genetic Markers of the Host to Predict the Efficacy of Colorectal Cancer Targeted Therapy

The introduction of anti-EGFR (cetuximab and panitumumab) and antiangiogenic (bevacizumab, regorafeninb, ramucirumab, and aflibercept) agents in the therapeutic armamentarium of the metastatic colorectal cancer (CRC) has significantly improved the therapeutic efficacy and patients survival. However, despite the great improvements achieved in the patients life expectation, the high inter-individual heterogeneity in the response to the targeted agents still represent an issue for the management of advanced CRC patients. Even if the role of tumor genetic mutations as predictive markers of drug efficacy has been well-established, the contribution of the host genetic markers is still controversial. Promising results regard the germ-line immune-profile, inflammation and tumor microenvironment. Inherent variations in KRAS 3'UTR region as well as EGF/ EGFR genes were investigated as markers of cetuximab effectiveness. More recently interesting data in the field of anti- EGFR agents were generated also for germ-line variants in genes involved in inflammation (e.g. COX-2, LIFR, IGF1 signaling), immune system (e.g., FCGRs, IL-1RA), and other players of the RAS signaling, including the Hippo pathway related genes (e.g. Rassf, YAP, TAZ). Host genetic variants in VEGF-dependent (i.e., EGF, IGF-1, HIF1α, eNOS, iNOS) and -independent (i.e., EMT cascade, EGFL7) pathways, with specific attention on inflammation and immune system-related factors (e.g., IL-8, CXCR-1/2, CXCR4-CXCL12 axis, TLRs, GADD34, PPP1R15A, ANXA11, MKNK1), were investigated as predictive markers of bevacizumab outcome, generating some promising results. In this review, we aimed to summarize the most recent literature data regarding the potential role of common and rare inhered variants in predicting which CRC patients will benefit more from a specifically targeted drug administration.

Transcriptomic Analyses Revealed Systemic Alterations in Gene Expression in Circulation and Tumor Microenvironment of Colorectal Cancer Patients

Colorectal cancer (CRC) is among the leading causes of cancer-related deaths worldwide, underscoring a need for better understanding of the disease and development of novel diagnostic biomarkers and therapeutic interventions. Herein, we performed transcriptome analyses on peripheral blood mononuclear cells (PBMCs), CRC tumor tissue and adjacent normal tissue from 10 CRC patients and PBMCs from 15 healthy controls. Up regulated transcripts from CRC PBMCs were associated with functions related to immune cell trafficking and cellular movement, while downregulated transcripts were enriched in cellular processes related to cell death. Most affected signaling networks were those involved in tumor necrosis factor (TNF) and interleukin signaling. The expression of selected immune-related genes from the RNA-Seq data were further validated using qRT-PCR. Transcriptome analysis of CRC tumors and ingenuity pathway analysis revealed enrichment in several functional categories related to cellular movement, cell growth and proliferation, DNA replication, recombination and repair, while functional categories related to cell death were suppressed. Upstream regulator analysis revealed activation of ERBB2 and FOXM1 networks. Interestingly, there were 18 common upregulated and 36 common downregulated genes when comparing PBMCs and tumor tissue, suggesting transcriptomic changes in the tumor microenvironment could be reflected, in part, in the periphery with potential utilization as disease biomarkers.

The Reciprocal Interaction Between LncRNA CCAT1 and miR-375-3p Contribute to the Downregulation of IRF5 Gene Expression by Solasonine in HepG2 Human Hepatocellular Carcinoma Cells

Solasonine (SS), a natural glycoalkaloid component, has been shown to have potent inhibitory activity and cytotoxicity against many cancer types. However, the precise mechanisms underlying this, particularly in hepatocellular carcinoma (HCC) are poorly understood. In this study, we showed that SS inhibited growth of HCC cells. Mechanistically, we observed that SS increased the expression of miR-375-3p, whereas reducing levels of long non-coding RNAs (lncRNAs) CCAT1 was noticed in HepG2 HCC and other cells. In addition, we found that SS repressed transcription factors, SP1 and interferon regulatory factor 5 (IRF5), protein expressions. There was a reciprocal interaction among miR-375-3p, CCAT1, and SP1. Moreover, SS inhibited IRF5 promoter activity, which was not observed in cells transfected with excessive expressed SP1 vectors. Interestingly, exogenously expressed IRF5 was shown to reverse expressions of SS-inhibited CCAT1 and induced-miR-375-3p; and neutralized SS-inhibited growth of HCC cells. Similar results were also found in vivo mouse model. Collectively, our results show that SS inhibits HepG2 HCC growth through the reciprocal regulation between the miR-375-3p and lncRNA CCAT1, and this results in transcription factor SP1-mediated reduction of IRF5 expression. The regulations and interactions among miR-375-3p, CCAT1, SP1, and IRF5 axis unveil a novel molecular mechanism underlying the anti-HCC growth by SS. IRF5 may be a potential target for treatment of HCC.

Serum level and single-nucleotide polymorphisms of toll-like receptor-7 among urinary bladder cancer Iraqi patients

Background

Toll-like receptor 7 (TLR7), a member of TLR family, plays a pivotal role in pathogenesis of different malignancies. Among these is urinary bladder cancer (UBC), which has not been extensively studied. Therefore, it was aimed to determine TLR7 serum level in UBC patients and evaluate its association with some demographic and clinicopathological characteristics. In addition, four TLR7 single-nucleotide polymorphisms (SNPs: rs179018, rs179019, rs179020, and rs179021) were investigated to determine their susceptibility role in UBC and inspect SNP’s impact on TLR7 level. Sixty-six UBC Iraqi patients were enrolled in this case-control study. Two control samples were also involved, 40 urinary tract infection (UTI) patients, and 48 healthy control subjects.

Results

Male gender, older age, and cigarette-smoking are risk factors for UBC. TLR7 level showed a significant decreased median in UBC patients compared to UTI patients or control (1.4 vs. 8.1 and 9.5 ng/ml, respectively; p < 0.001). The decrease was more pronounced in males, age group ≥ 48 years, cigarette-smokers, alcohol non-consumers, clinical stages I–II, and superficial tumor, as well as patients with family history of cancer and untreated patients. Mitomycin C and Bacillus Calmette–Guérin therapies tended to increase TLR7 level. Among the four investigated SNPs, only rs179019 C allele showed significantly uncorrected increased frequency in UBC males compared to control males (p = 0.038), while among UTI females, C allele frequency maintained a significantly corrected decreased frequency compared to control females (p = 0.005). Some SNPs influenced serum level of TLR7, but a significant impact was recorded for rs179019 in UTI females (p = 0.006).

Conclusions

Downregulation of TLR7 is suggested to have a role in etiology and pathogenesis of UBC, especially the male, elderly and smoker patients. Mitomycin C and Bacillus Calmette–Guérin may enhance TLR7 production in the blood of UBC patients. TLR7 SNPs are suggested to influence susceptibility to develop UBC, and their potential in impacting TLR7 serum level is augmented.

Targeting Toll-Like Receptors for Cancer Therapy

The immune system encompasses a broad array of defense mechanisms against foreign threats, including invading pathogens and transformed neoplastic cells. Toll-like receptors (TLRs) are critically involved in innate immunity, serving as pattern recognition receptors whose stimulation leads to additional innate and adaptive immune responses. Malignant cells exploit the natural immunomodulatory functions of TLRs, expressed mainly by infiltrating immune cells but also aberrantly by tumor cells, to foster their survival, invasion, and evasion of anti-tumor immune responses. An extensive body of research has demonstrated context-specific roles for TLR activation in different malignancies, promoting disease progression in certain instances while limiting cancer growth in others. Despite these conflicting roles, TLR agonists have established therapeutic benefits as anti-cancer agents that activate immune cells in the tumor microenvironment and facilitate the expression of cytokines that allow for infiltration of anti-tumor lymphocytes and the suppression of oncogenic signaling pathways. This review focuses on the clinical application of TLR agonists for cancer treatment. We also highlight agents that are undergoing development in clinical trials, including investigations of TLR agonists in combination with other immunotherapies.

Immune Resistance and EGFR Antagonists in Colorectal Cancer

: Targeting the epidermal growth factor receptor (EGFR) either alone or in combination with chemotherapy in patients with RAS wild type metastatic colorectal cancer (mCRC) has revolutionized the treatment of CRC, but with less results than initially envisaged. In recent years, the discovery of multiple pathways leading to the escape from anti-EGFR therapy has revealed an enormous complexity and heterogeneity of human CRC due to the intrinsic genomic instability and immune/cancer cell interaction. Therefore, understanding the mechanistic basis of acquired resistance to targeted therapies represents a major challenge to improve the clinical outcomes of patients with CRC. The latest findings strongly suggest that complex molecular alterations coupled with changes of the immune tumor microenvironment may substantially contribute to the clinical efficacy of EGFR antagonist. In this review, we discuss the most recent findings that contribute to both primary and acquired anti-EGFR therapy resistance. In addition, we analyze how strategies aiming to enhance the favorable effects in the tumor microenvironment may contribute to overcome resistance to EGFR therapies.

The Role of Toll-Like Receptors in Oncotherapy

Toll-like receptors (TLRs) are associated with tumor growth and immunosuppression, as well as apoptosis and immune system activation. TLRs can activate apoptosis and innate and adaptive immunity pathways, which can be pharmacologically targeted for the development of anticancer oncotherapies. Several studies and clinical trials indicate that TLR agonists are promising adjuvants or elements of novel therapies, particularly when used in conjunction with chemotherapy or radiotherapy. An increasing number of studies suggest that the activation of TLRs in various cancer types is related to oncotherapy; however, before this finding can be applied to clinical practice, additional studies are required. Research suggests that TLR agonists may have potential applications in cancer therapy; nevertheless, because TLR signaling can also promote tumorigenesis, a critical and comprehensive evaluation of TLR action is warranted. This review focuses on recent studies that have assessed the strengths and weaknesses of utilizing TLR agonists as potential anticancer agents.

Toll like receptor signaling pathway as a potential therapeutic target in colorectal cancer

Toll like receptor (TLR) signaling is involved in activating innate and adaptive immune responses and plays a critical role in inflammation-induced diseases such as colorectal cancer (CRC). Dysregulation of this signaling pathway can result in disturbance of epithelial layer hemostasis, chronic inflammatory, excessive repair responses, and development of CRC. There is now substantial evidence for the benefit of targeting of this pathway in cancer treatment, and several agents have been approved, such as BCG (Bacillus Calmette Guérin), MPL (monophosphoryl lipid A) and imiquimod. This review summarizes the current knowledge about the different functions of TLRs on tumor cells and their application in cancer therapy with particular emphasis on recent preclinical and clinical research in treatment of CRC.