Signaling mechanisms of resistance to EGFR- and Anti-Angiogenic Inhibitors cancer

ACVRL1 drives resistance to multitarget tyrosine kinase inhibitors in colorectal cancer by promoting USP15-mediated GPX2 stabilization

BACKGROUND

Multitarget tyrosine kinase inhibitors (mTKIs) such as Regorafenib and Sorafenib have already been approved for the treatment of many solid tumours. However, the efficacy of mTKIs in colorectal cancer (CRC) is limited; the underlined mechanism remains largely elusive. Our study was aimed to find out the resistance mechanism of mTKIs in CRC.

METHODS

RNA sequencing was used to identify the expression of Activin A receptor-like type 1 (ACVRL1) under the treatment of mTKIs. Gain/loss-of-function experiments were performed to assess the biological function of ACVRL1 in resistance to mTKIs. The underlying mechanisms of ACVRL1-mediated mTKI resistance were investigated by using liquid chromatography-mass spectrometry assays (LC-MS), co-immunoprecipitation assays (Co-IP), chromatin immunoprecipitation assays, ubiquitination assays, dual luciferase reporter assays, etc. RESULTS: RNA sequencing identified the activation of ACVRL1 under the treatment of mTKIs in CRC cells. ACVRL1 knockdown and overexpression significantly affects the sensitivity of CRC cells to mTKIs both in vitro and vivo. Mechanistically, we found the β-catenin/TCF-1-KCNQ1OT1/miR-7-5p axis mediated the activation of ACVRL1. Furthermore, LC-MS assays indicated the interaction between ACVRL1 and glutathione peroxidase 2(GPX2) protein. IP assay defined ACVRL1 truncation (282-503aa) could be responsible for interacting with GPX2, and rescue experiments with ACVRL1 truncations confirmed the importance of this interaction in driving mTKI resistance. Co-IP assays confirmed that ACVRL1 associates with ubiquitin-specific peptidase 15(USP15) which directly deubiquinates GPX2 at the K187(K, lysine) site, leading to the accumulation of GPX2 protein. Rescue experiments performed with the lysine mutants in GPX2 CRISPR knockout cell model confirmed the importance of GPX2 K187 mutant. As a result, the increased ROS clearance and decreased cell apoptosis eventually lead to mTKI resistance in CRC.

CONCLUSIONS

Our results demonstrate that the Wnt/β-catenin/KCNQ1OT1/miR-7-5p/ACVRL1/GPX2 biological axis plays a vital role in CRC, targeting which may be an effective approach for overcoming mTKI resistance.

Recent advances in the application of probiotic yeasts, particularly Saccharomyces, as an adjuvant therapy in the management of cancer with focus on colorectal cancer

Today, the increasing rate of cancer-related mortality, has rendered cancer a major global challenge, and the second leading cause of death worldwide. Conventional approaches in the treatment of cancer mainly include chemotherapy, surgery, immunotherapy, and radiotherapy. However, these approaches still come with certain disadvantages, including drug resistance, and different side effects such as gastrointestinal (GI) irritation (e.g., diarrhea, mucositis). This has encouraged scientists to look for alternative therapeutic methods and adjuvant therapies for a more proper treatment of malignancies. Application of probiotics as an adjuvant therapy in the clinical management of cancer appears to be a promising strategy, with several notable advantages, e.g., increased safety, higher tolerance, and negligible GI side effects. Both in vivo and in vitro analyses have indicated the active role of yeast probiotics in mitigating the rate of cancer cell proliferation, and the induction of apoptosis through regulating the expression of cancer-related genes and cellular pathways. Strain-specific anti-cancer activities of yeast probiotics strongly suggest that their administration along with the current cancer therapies may be an efficient method to reduce the side effects of these approaches. The main purpose of this article is to evaluate the efficacy of yeast probiotics in alleviating the adverse effects associated with cancer therapies.

Evolution of the Experimental Models of Cholangiocarcinoma

Cholangiocarcinoma (CCA) is a rare, aggressive disease with poor overall survival. In advanced cases, surgery is often not possible or fails; in addition, there is a lack of effective and specific therapies. Multidisciplinary approaches and advanced technologies have improved the knowledge of CCA molecular pathogenesis, highlighting its extreme heterogeneity and high frequency of genetic and molecular aberrations. Effective preclinical models, therefore, should be based on a comparable level of complexity. In the past years, there has been a consistent increase in the number of available CCA models. The exploitation of even more complex CCA models is rising. Examples are the use of CRISPR/Cas9 or stabilized organoids for in vitro studies, as well as patient-derived xenografts or transgenic mouse models for in vivo applications. Here, we examine the available preclinical CCA models exploited to investigate: (i) carcinogenesis processes from initiation to progression; and (ii) tools for personalized therapy and innovative therapeutic approaches, including chemotherapy and immune/targeted therapies. For each model, we describe the potential applications, highlighting both its advantages and limits.

Novel benzoate-lipophilic cations selectively induce cell death in human colorectal cancer cell lines

INTRODUCTION

Colorectal cancer (CRC) is a critical health issue worldwide. The high rate of liver and lung metastasis associated with CRC creates a significant barrier to effective and efficient therapy. Tumour cells, including CRC cells, have metabolic alterations, such as high levels of glycolytic activity, increased cell proliferation and invasiveness, and chemo- and radio-resistance. However, the abnormally elevated mitochondrial transmembrane potential of these cells also provides an opportunity to develop drugs that selectively target the mitochondrial functions of tumour cells.

METHODS

In this work, we used a new batch of benzoic acid esters with cytotoxic activities attached to the triphenylphosphonium group as a vehicle to target tumour mitochondria and improve their activity. We evaluated the cytotoxicity, selectivity, and mechanism of action of these derivatives, including the effects on energy stress-induced apoptosis and metabolic behaviour in the human CRC cell lines HCT-15 and COLO-205.

RESULTS

The benzoic acid derivatives selectively targeted the tumour cells with high potency and efficacy. The derivatives induced the uncoupling of the oxidative phosphorylation system, decreased the transmembrane potential, and reduced ATP levels while increasing AMPK activation, thereby triggering tumour cell apoptosis in both tumour cell lines tested.

CONCLUSION

The benzoic acid derivatives studied here are promising candidates for assessing in vivo models of CRC, despite the diverse metabolic characteristics of these tumour cells.

An overview of yeast probiotics as cancer biotherapeutics: possible clinical application in colorectal cancer

The previous reports have established a strong link between diet, lifestyle, and gut microbiota population with the onset of the colorectal cancer (CRC). Administration of probiotics has become a particular interest in prevention and treatment of CRC. As potential dietary complements, probiotics might be able to lower the risk of CRC and manage the safety of traditional cancer therapies such as surgery, radiation therapy, and chemotherapy. This review investigates the promising effects of probiotics as biotherapeutics, with due attention to possible clinical application of yeast probiotics in prevention and treatment of CRC. In addition, various underlying anti-cancer mechanisms are covered here based on scientific evidence and findings from numerous experimental studies. Application of probiotics as biotherapeutics in CRC, however, needs to be approved by human clinical trials. It is of prime concern, to find potential probiotic strains, effective doses for administrations and regimes, and molecular mechanisms involved in prevention and treatment.

Knockout of glucosidase II beta subunit inhibits growth and metastatic potential of lung cancer cells by inhibiting receptor tyrosine kinase activities

Glucosidase II (GluII) plays a major role in regulating post-translation modification of N-linked glycoproteins. We have previously reported that the expression of glucosidase II beta subunit (GluIIβ) was significantly increased in lung tumor tissues and its suppression triggers autophagy and/or apoptosis. Here, we investigated the role of GluIIβ in cell growth, metastatic potential, and receptor tyrosine kinases (RTKs) signaling activity in lung carcinoma cell lines. CRISPR-CAS9 technology was used to knockout the GluIIβ encoding gene (PRKSH) in lung carcinoma cells. GluIIβ knockout cells exhibited drastically slower growth rates in comparison to non-target transfected cells, particularly with lower concentrations of fetal bovine serum, indicating impairment of their ability to survive under nutritional deprivation. Cell migration and anchorage-independent growth, the fundamental components of cancer cell metastasis, were significantly decreased in GluIIβ knockout cells. Knockout of GluIIβ increased the sensitivity of lung cancer cells to cisplatin but reduced their sensitivity to gefitinib. Interestingly, knocking out of GluIIβ lowered overall RTK signaling activities to less than half of those in non-target transfected cells, which could represent a novel strategy for blocking multiple RTKs in tumor cells in an effort to improve lung cancer treatment.

Rhein sensitizes human pancreatic cancer cells to EGFR inhibitors by inhibiting STAT3 pathway

Background

Rhein is a lipophilic anthraquinone extensively found in medicinal herbs. Emerging evidence suggests that rhein has significant antitumor effects, supporting its potential use as an antitumor agent. The IL6/STAT3 signaling pathway has been suggested as an attractive target for the discovery of novel cancer therapeutics.

Methods

The human pancreatic cancer cell lines AsPC-1, Patu8988T, BxPC-3 and PANC-1, and immunodeficient mice were chosen as models to study the effects of rhein. The potent antiproliferative and proapoptotic effects of rhein were examined by cell viability, cellular morphology, apoptosis and colony formation assays. The STAT3 luciferase report assay, immunostaining analysis and Western blot analysis revealed the inhibition of the IL6/STAT3 signaling axis.

Results

Apoptosis was induced by adjunctive use of rhein with epidermal growth factor receptor (EGFR) inhibitors in pancreatic cancer cells as verified by cell apoptosis analysis and changes in the expression level of apoptotic/anti-apoptotic proteins BCL-2, BAX, Caspase 3 and Cl-PARP. Suppression of the phosphorylation of STAT3 and EGFR were also observed as a result of the treatment with a combination of rhein and EGFR inhibitors. Most interestingly, it was found that rhein considerably sensitized cells to erlotinib, thus suppressing tumor growth in PANC-1 and BxPC-3 xenograft models. The in vivo anti-tumor effect was associated with increased apoptosis and combined inhibition of the STAT3 and EGFR pathways in tumor remnants.

Conclusions

Rhein sensitizes human pancreatic cancer cells to EGFR inhibitors through inhibition of STAT3. Taken together, the results indicate that rhein offers a novel blueprint for pancreatic cancer therapy, particularly when combined with EGFR inhibitors.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-1015-9) contains supplementary material, which is available to authorized users.

Altered Expression of Sphingosine-1-Phosphate Metabolizing Enzymes in Oral Cancer Correlate With Clinicopathological Attributes

We have determined the gene expression of sphingosine-1-phosphate (S1P) metabolizing enzymes (SphK1, SphK2, SGPL1, SGPP1, SGPP2, PPAP2A, PPAP2B, and PPAP2C) by quantitative real-time polymerase chain reaction in tumor tissues and adjacent normal tissues of 50 oral squamous cell carcinoma (OSCC) patients. Expression of SphK1 and SGPP1 genes was up-regulated significantly in 70% and 75% OSCC tumors respectively. Importantly, expression of SphK2 and PPAP2B was down-regulated in the tumor tissues of 70% OSCC patients. Expression of SphK2 and PPAP2B negatively correlated with tumor-node-metastasis (TNM) staging and tumor volume respectively. Furthermore, LPP1 is an independent predictor of TNM staging and lymph node ratio.

Mineralocorticoid regulation of cell function: the role of rapid signalling and gene transcription pathways

The mineralocorticoid receptor (MR) and mineralocorticoids regulate epithelial handling of electrolytes, and induces diverse effects on other tissues. Traditionally, the effects of MR were ascribed to ligand-receptor binding and activation of gene transcription. However, the MR also utilises a number of intracellular signalling cascades, often by transactivating unrelated receptors, to change cell function more rapidly. Although aldosterone is the physiological mineralocorticoid, it is not the sole ligand for MR. Tissue-selective and mineralocorticoid-specific effects are conferred through the enzyme 11β-hydroxysteroid dehydrogenase 2, cellular redox status and properties of the MR itself. Furthermore, not all aldosterone effects are mediated via MR, with implication of the involvement of other membrane-bound receptors such as GPER. This review will describe the ligands, receptors and intracellular mechanisms available for mineralocorticoid hormone and receptor signalling and illustrate their complex interactions in physiology and disease.

Inherent formulation issues of kinase inhibitors

The small molecular Kinase Inhibitor (smKI) drug class is very promising and rapidly expanding. All of these drugs are administered orally. The clear relationship between structure and function has led to drugs with a general low intrinsic solubility. The majority of the commercial pharmaceutical formulations of the smKIs are physical mixtures that are limited by the low drug solubility of a salt form. This class of drugs is therefore characterized by an impaired and variable bioavailability rendering them costly and their therapies suboptimal. New formulations are sparingly being reported in literature and patents. The presented data suggests that continued research into formulation design can help to develop more efficient and cost-effective smKI formulation. Moreover, it may also be of help in the future design of the formulations of new smKIs.

Cellular and molecular effects of yeast probiotics on cancer

The cancer is one of the main causes of human deaths worldwide. The exact mechanisms of initiation and progression of malignancies are not clear yet, but there is a common agreement about the role of colonic microbiota in the etiology of different cancers. Probiotics have been examined for their anti-cancer effects, and different mechanisms have been suggested about their antitumor functions. Nonpathogenic yeasts, as members of probiotics family, can be effective on gut microbiota dysbiosis. Generally safe yeasts have shown so many beneficial effects on human health. Probiotic yeasts influence physiology, metabolism, and immune homeostasis in the colon and contribute to cancer treatment due to possessing anti-inflammatory, anti-proliferative and anti-cancer properties. This study reviews some of the health-beneficial effects of probiotic yeasts and their biological substances like folic acid and β-glucan on cancer and focuses on the possible cellular and molecular mechanisms of probiotic yeasts such as influencing pathogenic bacteria, inactivation of carcinogenic compounds, especially those derived from food, improvement of intestinal barrier function, modulation of immune responses, antitoxic function, apoptosis, and anti-proliferative effects.

Mutational analysis of primary and metastatic colorectal cancer samples underlying the resistance to cetuximab-based therapy

PURPOSE

Although several molecular markers predicting resistance to cetuximab- or panitumumab-based therapy of metastatic colorectal cancer were described, mutations in RAS proto-oncogenes remain the only predictors being used in daily clinical practice. However, 35%-45% of wild-type RAS patients still do not respond to this anti-epidermal growth factor receptor (anti-EGFR) monoclonal antibody-based therapy, and therefore the definition of other predictors forms an important clinical need. The aim of the present retrospective single-institutional study was to evaluate potential genes responsible for resistance to anti-EGFR therapy in relation to mutational analysis of primary versus metastatic lesions.

PATIENTS AND METHODS

Twenty-four paired primary and corresponding metastatic tissue samples from eight nonresponding and four responding metastatic colorectal cancer patients treated with cetuximab-based therapy were sequenced using a next-generation sequencing panel of 26 genes involved in EGFR signaling pathway and colorectal carcinogenesis.

RESULTS

Mutational status of primary tumors and metastatic lesions was highly concordant in TP53, APC, CTNNB1, KRAS, PIK3CA, PTEN, and FBXW7 genes. Metastatic samples harbor significantly more mutations than primary tumors. Potentially negative predictive value of FBXW7 mutations in relationship to anti-EGFR treatment outcomes was confirmed. Finally, new occurrences of activating KRAS mutations were identified in a group of patients initially determined as wild-type RAS by routinely used qPCR-based RAS mutational tests. All newly detected activating KRAS mutations most likely led to cetuximab treatment failure.

CONCLUSION

The results of the present study suggest a need of careful consideration of previously published results of anti-EGFR-targeted therapy with regard to potentially inaccurate diagnostic tools used in the past. Based on our findings, we recommend more extensive use of next-generation sequencing testing in daily clinical practice, as it brings a significant added value in terms of validity of the diagnostic procedure.

Does the addition of drugs targeting the vascular endothelial growth factor pathway to first-line chemotherapy increase complete response? A meta-analysis of randomized clinical trials

Drugs targeting the vascular endothelial growth factor (VEGF) and its receptor (VEGFR) signaling (anti-VEGF/VEGFR drugs) are the most validated anti-angiogenic strategies for cancer treatment. Complete response (CR) is a rare event in cancer patients receiving chemotherapy. A meta-analysis was conducted to determine whether adding anti-VEGF/VEGFR drugs to chemotherapy can further increase the chance of CR in the first-line therapy. Relevant databases were systematically searched for the period 2000-2015. Eligible studies were selected according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The incidence, relative risk (RR), and 95 % confidence intervals (CIs) were calculated using random-effects or fixed-effects models based on the heterogeneity of selected studies. A total of 12,453 patients from 28 randomized controlled trials were included. The overall incidence of CR in patients treated with anti-VEGF/VEGFR drugs plus chemotherapy was 1.5 % (95 % CI, 1.0-2.0 %) compared to 1.1 % (95 % CI, 0.7-1.4 %) in the chemotherapy-alone arm. Adding anti-VEGF/VEGFR drugs was associated with significant improvement of CR (RR, 1.52, 95 % CI, 1.18-1.95, P = 0.001). When stratified by drug type, adding VEGFR tyrosin kinase inhibitors (TKIs) did not increase the chance of CR (RR, 0.87, 95 % CI, 0.51-1.49; P = 0.614). The addition of bevacizumab with 7.5 mg/kg every 3 weeks, but not 15 mg/kg every 3 weeks, significantly improves the CR (7.5 mg, RR, 2.43, 95 % CI, 1.64-3.60, P = 0.000; 15 mg, RR, 1.07, 95 % CI, 0.63-1.81, P = 0.799). In subgroup analysis, a significant improvement of CR by the addition of anti-VEGF/VEGFR drugs was observed in patients with colorectal cancer (RR, 2.10, 95 % CI 1.21-3.63, P = 0.008), ovarian cancer (RR, 3.07; 95 % CI, 1.68-5.62, P = 0.000), and patients who are treated with platinum-based regimens (RR, 1.78, 95 % CI, 1.23-2.59, P = 0.002). Low-dose bevacizumab, rather than VEGFR TKIs or high-dose bevacizumab, can increase the chance of CR in patients receiving chemotherapy.