Targeting HER2-positive breast cancer cells by a combination of dasatinib and BMS-202: Insight into the molecular pathways.

BACKGROUND: Recent investigations have reported the benefits of using a tyrosine kinase inhibitor, dasatinib (DA), as well as programmed death-ligand 1 (PD-L1) inhibitors in the management of several solid tumors, including breast cancer. Nevertheless, the outcome of the combination of these inhibitors on HER2-positive breast cancer is not explored yet. METHODS: Herein, we investigated the impact of DA and PD-L1 inhibitor (BMS-202) combination on HER2-positive breast cancer cell lines, SKBR3 and ZR75. RESULTS: Our data reveal that the combination significantly inhibits cell viability of both cancer cell lines as compared to monotreatment. Moreover, the combination inhibits epithelial-mesenchymal transition (EMT) progression and reduces cancer cell invasion by restoring E-cadherin and ß-catenin expressions and loss of vimentin, major biomarkers of EMT. Additionally, the combination reduces the colony formation of both cell lines in comparison with their matched control. Also, the combination considerably inhibits the angiogenesis of the chorioallantoic membrane model compared with monotreatment. Molecular pathway analysis of treated cells shows that this combination blocks HER2, AKT, ß-catenin, and JNK1/2/3 activities. CONCLUSION: Our findings implicate that a combination of DA and BMS-202 could have a significant impact on the management of HER2-positive breast cancer.

Incidence of HPVs, EBV, and MMTV-Like Virus in Breast Cancer in Qatar.

INTRODUCTION: Human papillomaviruses (HPVs), Epstein-Barr virus (EBV), and mouse mammary tumor virus-like virus (MMTV-like virus) can be present and contribute to breast cancer development and progression. However, the role of these oncoviruses and their crosstalk in breast cancer is still unclear. METHODS: We explored the co-presence of high-risk HPVs, EBV, and MMTV-like virus in 74 breast cancer samples from Qatar using PCR. RESULTS: We found the presence of HPV and EBV in 65% and 49% of our cancer sample cohorts; 47% of the samples are positive for both oncoviruses. The MMTV-like virus alone was detected in 15% of the samples with no significant association with clinicopathological features. The three oncoviruses were co-present in 14% of the cases; no significant association was noted between the co-presence of these viruses and the clinicopathological features. CONCLUSION: Despite the presence of the oncoviruses, additional studies are necessary to understand their interactions in human breast carcinogenesis.

High-risk human papillomaviruses and Epstein-Barr virus in breast cancer in Lebanese women and their association with tumor grade: a molecular and tissue microarray study.

BACKGROUND: High-risk human papillomaviruses (HPVs) are present and can cooperate with Epstein-Barr virus (EBV) to initiate and/or enhance the progression of several types of human carcinomas including cervical as well as head and neck; in parallel, it has been recently pointed out that these oncoviruses can be detected in human breast cancers. Thus, we herein explored the presence/co-presence of high-risk HPVs and EBV in breast cancer in Lebanese women. METHODS: A cohort of 102 breast cancer samples and 14 normal breast tissues were assessed for the presence of HPVs and EBV. Polymerase chain reaction (PCR) and immunohistochemistry (IHC) analysis in addition to tissue microarray (TMA) platform were used in this study. RESULTS: We found the presence of HPV in 66/102 (65%) of our samples, while EBV is present in 41/102 (40%) of the cohort. Additionally, our data showed that high-risk HPV types (52, 35, 58, 45, 16 and 51) are the most frequent in breast cancer in Lebanese women. Meanwhile, we report that high-risk HPVs and EBV are co-present in 30/102 (29%) of the samples; more significantly, our results indicate that their co-presence is associated with tumor grade (p = 0.03). CONCLUSION: Our data revealed that HPVs and EBV are present/co-present in human breast cancer where they may play an important role in its development and/or progression; thus, we believe that further investigations are essential to confirm and elucidate the presence/co-presence of these oncoviruses and the underlying mechanisms of their interaction in breast carcinogenesis.

The Effect of Surface-Modified Gold Nanorods on the Early Stage of Embryonic Development and Angiogenesis: Insight into the Molecular Pathways.

Gold nanorods have been implicated in several biomedical applications. Herein, the effect of two surface-modified gold nanorods on the early stages of embryogenesis and angiogenesis was investigated using avian embryos at three days and their chorioallantoic membrane (CAM) at five days of incubation. We found that gold nanorods (GNR) modified with PEGylated phospholipid moiety show a high mortality rate in embryos after four days of exposure compared to GNR modified with PEGylated cholesterol moiety. Meanwhile, our data revealed that surface modified-GNR significantly inhibit the formation of new blood vessels in the treated CAM model after 48 h of exposure. Moreover, we report that surface-modified GNR significantly deregulate the expression of several genes implicated in cell proliferation, invasion, apoptosis, cellular energy metabolism, and angiogenesis. On the other hand, our data point out that GNR treatments can modulate the expression patterns of JNK1/2/3, NF-KB/p38, and MAPK, which could be the main molecular pathways of the nanorods in our experimental models.

Gelatin-methacryloyl hydrogel based in vitro blood-brain barrier model for studying breast cancer-associated brain metastasis.

Breast cancer is one of the leading causes of brain metastasis. Metastasis to the brain occurs if cancer cells manage to traverse the 'blood-brain barrier' (BBB), which is a barrier with a very tight junction (TJ) of endothelial cells between blood circulation and brain tissue. It is highly important to develop novel in vitro BBB models to investigate breast cancer metastasis to the brain to facilitate the screening of chemotherapeutic agents against it. We herein report the development of gelatin methacryloyl (GelMA) modified transwell insert based BBB model composed of endothelial and astrocyte cell layers for testing the efficacy of anti-metastatic agents against breast cancer metastasis to the brain. We characterized the developed model for the morphology and in vitro breast cancer cell migration. Furthermore, we investigated the effect of cisplatin, a widely used chemotherapeutic agent, on the migration of metastatic breast cancer cells using the model. Our results showed that breast cancer cells migrate across the developed BBB model. Cisplatin treatment inhibited the migration of cancer cells across the model. Findings of this study suggest that our BBB model can be used as a suitable tool to investigate breast cancer-associated brain metastasis and to identify suitable therapeutic agents against this.

Co-presence of human papillomaviruses and Epstein-Barr virus is linked with advanced tumor stage: a tissue microarray study in head and neck cancer patients.

BACKGROUND: Human papillomaviruses (HPVs) and Epstein-Barr virus (EBV), known oncoviruses, can be co-present and cooperate in the initiation and/or progression of human carcinomas, including head and neck. Based on this fact, we recently reported the prevalence of both HPVs and EBV in cervical and breast cancers. METHODS: We herein explore for the first time the co-prevalence of high-risk HPVs and EBV in 98 head and neck (HN) squamous cell carcinoma (SCC) tissues from Bosnian patients using polymerase chain reaction (PCR) and immunohistochemistry (IHC) analysis, as well as tissue microarray methodology. RESULTS: The majority of these cancer tissue cases were from the oral cavity (68%). We found that high-risk HPVs and EBV are co-present in 34.7% of the SCC samples; with a significant correlation between the various HPV types and EBV co-incidence (p = 0.03). Our data showed that 30.8% of oral SCCs are positive for E6 oncoprotein of high-risk HPVs and 44.6% are positive for LMP1 of EBV. The most commonly expressed HPVs in our HNSCC samples include HPV types 16, 18, 45 and 58. Additionally, 37.5% of oral SCCs are positive for both HPVs and EBV, with statistically significant association between high-risk HPV types and EBV (p < 0.05). More importantly, our data revealed that the co-presence of HPV and EBV is strongly correlated with advanced tumor stage (p = 0.035). CONCLUSION: In this study we show that HPV and EBV oncoviruses are co-present in HNSCC, particularly in oral cancer, where they can cooperate in the initiation and/or progression of this cancer. Thus, further studies are necessary to elucidate the mechanism of this cooperation.

Molecular Mechanisms of Colon Cancer Progression and Metastasis: Recent Insights and Advancements.

Colorectal cancer (CRC), the third most common type of cancer, is the second leading cause of cancer-related mortality rates worldwide. Although modern research was able to shed light on the pathogenesis of CRC and provide enhanced screening strategies, the prevalence of CRC is still on the rise. Studies showed several cellular signaling pathways dysregulated in CRC, leading to the onset of malignant phenotypes. Therefore, analyzing signaling pathways involved in CRC metastasis is necessary to elucidate the underlying mechanism of CRC progression and pharmacotherapy. This review focused on target genes as well as various cellular signaling pathways including Wnt/ß-catenin, p53, TGF-ß/SMAD, NF-κB, Notch, VEGF, and JAKs/STAT3, which are associated with CRC progression and metastasis. Additionally, alternations in methylation patterns in relation with signaling pathways involved in regulating various cellular mechanisms such as cell cycle, transcription, apoptosis, and angiogenesis as well as invasion and metastasis were also reviewed. To date, understanding the genomic and epigenomic instability has identified candidate biomarkers that are validated for routine clinical use in CRC management. Nevertheless, better understanding of the onset and progression of CRC can aid in the development of early detection molecular markers and risk stratification methods to improve the clinical care of CRC patients.

Elaeagnus angustifolia Plant Extract Inhibits Epithelial-Mesenchymal Transition and Induces Apoptosis via HER2 Inactivation and JNK Pathway in HER2-Positive Breast Cancer Cells.

Elaeagnus angustifolia (EA) is a medicinal plant used for treating several human diseases in the Middle East. Meanwhile, the outcome of EA extract on HER2-positive breast cancer remains nascent. Thus, we herein investigated the effects of the aqueous EA extract obtained from the flowers of EA on two HER2-positive breast cancer cell lines, SKBR3 and ZR75-1. Our data revealed that EA extract inhibits cell proliferation and deregulates cell-cycle progression of these two cancer cell lines. EA extract also prevents the progression of epithelial-mesenchymal transition (EMT), an important event for cancer invasion and metastasis; this is accompanied by upregulations of E-cadherin and ß-catenin, in addition to downregulations of vimentin and fascin, which are major markers of EMT. Thus, EA extract causes a drastic decrease in cell invasion ability of SKBR3 and ZR75-1 cancer cells. Additionally, we found that EA extract inhibits colony formation of both cell lines in comparison with their matched control. The molecular pathway analysis of HER2 and JNK1/2/3 of EA extract exposed cells revealed that it can block HER2 and JNK1/2/3 activities, which could be the major molecular pathway behind these events. Our findings implicate that EA extract may possess chemo-preventive effects against HER2-positive breast cancer via HER2 inactivation and specifically JNK1/2/3 signaling pathways.

Water-pipe smoking promotes epithelial-mesenchymal transition and invasion of human breast cancer cells via ERK1/ERK2 pathways.

BACKGROUND: With the increasing popularity of water-pipe smoking (WPS), it is critical to comprehend how WPS may affect women's health. The main goal of this study is to identify the potential outcome of WPS on human breast cancer progression. METHODS: Two breast cancer cell lines, MCF7 and BT20, were used in this investigation. We explored the outcome of WPS on cell morphology and cell invasion using inverted microscope and Biocoat Matrigel invasion chambers. On the other hand, Western blot was employed to study the expression patterns of key control genes of cell adhesion and invasion. RESULTS: Our data reveal that WPS induces epithelial-mesenchymal transition (EMT) of MCF7 and BT20 breast cancer cell lines; thus, WPS enhances cell invasion ability of both cell lines in comparison with their matched controls. More significantly, WPS provokes a down- and up-regulation of E-cadherin and focal adhesion kinase (FAK), respectively, which are important key regulators of cancer progression genes. Finally, our data point out that WPS incites the activation of Erk1/Erk2, which could be behind the stimulation of EMT and invasion as well as the deregulation of E-cadherin and FAK expression. CONCLUSION: Our data show, for the first time, that WPS initiates EMT and stimulates cell invasion of breast cancer cells, which could incite metastatic development in breast cancer patients. Thus, we believe that further studies, both in vitro and in vivo, are required to elucidate the pathogenic outcome of WPS on cancer progression of several human carcinomas including breast.

Substantial Toxic Effect of Water-Pipe Smoking on the Early Stage of Embryonic Development.

Background: Water-pipe smoking (WPS) is the most widespread tobacco use in the Middle-East, and is rapidly spreading globally. Smoke from WP contains most of the compounds present in cigarette smoke, although in different proportions. WPS is associated with the risk of several human diseases; however, its impact on the early stage of normal development has not been investigated yet. Thus, in this investigation, we assess the effect of WPS on the embryo at the early stage of development. Methods: Chicken embryos at 3 days of incubations were used in this study. Meanwhile, we explored the outcome of WPS on angiogenesis using the chorioallantoic membrane (CAM) of the chicken embryos. Finally, quantitative real-time polymerase chain reaction was used to study the regulation of some key control genes of cell proliferation, apoptosis, and migration. Results: Our data reveal that WPS inhibits angiogenesis of the CAM and in embryos in comparison with their matched controls; in addition, WPS-exposed embryos show slight reduction in their sizes. We also noted that around 80% of WPS-exposed embryos die before 10 days of incubation. More significantly, WPS induces upregulations of BCL-2, Caspase-8, ATF-3, INHIB-A, and Cadherin 6 genes, which are important key regulators of cell apoptosis, proliferation, and migration. Conclusion: Our data reveal, for the first time, that WPS has very toxic effects during the early stage of embryogenesis. Thus, we believe that further studies are required to elucidate the pathogenic effect of WPS on human health especially on the embryo at the early stage of its development. Implications: This investigation addresses an important gap on the outcome of WPS during the early stage of embryogenesis. Data of this study point out that WPS can have a very toxic effect on the embryo at this stage. Additionally, results from this report display for the first time that WPS can damage normal angiogenesis of the embryo thus provoking a significant number of embryonic death. Moreover, this study reveals that this effect can occur via the deregulation of several genes related to cell apoptosis, proliferation, and migration.

Effects of neratinib on angiogenesis and the early stage of the embryo using chicken embryo as a model.

Angiogenesis is the process of forming new blood capillaries from pre-existing vessels. Even though it is essential during normal development, it plays a major role in cancer progression. Neratinib is a pan-human epidermal growth factor receptor (HER) inhibitor that has recently been approved for the treatment of HER2-positive breast cancer. However, its effects on angiogenesis and embryogenesis remain unknown. This study examined the antiangiogenic effects of neratinib using the chorioallantoic membrane (CAM) of chicken embryos. We also evaluated neratinib's toxicity during the early stages of normal development using the chicken embryos, primary embryonic fibroblasts (EFBs), and human umbilical vein endothelial cells (HUVEC). Our findings revealed that neratinib significantly inhibited the CAM angiogenesis compared to controls by reducing vessel percentage area and the average vessel length. Furthermore, neratinib downregulated vascular endothelial growth factor (VEGF), a key mediator of angiogenesis. At lower concentrations, neratinib was well-tolerated during early stages of normal development. Additionally, EFBs treated with neratinib showed no morphological or viability changes when compared to controls. However, at the highest concentration tested, neratinib treatment reduced HUVEC cell viability. This effect may be associated with the dysregulation of key apoptotic genes, including caspase-3, caspase-8, caspase-9, and the B-cell lymphoma 2 (Bcl2) gene. Our findings indicate a novel potential application of neratinib as an antiangiogenic agent, exhibiting tolerable toxicity in the early stages of embryogenesis.

Significant toxic role for single-walled carbon nanotubes during normal embryogenesis.

In order to investigate the effect of SWCNTs in the embryo, we examined the outcome of SWCNTs in avian embryo at an early stage of development. We found that SWCNTs-treatment inhibits the angiogenesis of the chorioallantoic membrane (CAM) and in the chicken embryo. Moreover, we showed that SWCNTs can harm the normal development of the embryo since all SWCNTs-exposed embryos are smaller in comparison with their matched controls. We also found that the majority of SWCNTs-exposed embryos die before 12days of incubation. Macroscopic examination did not reveal any anomalies in these embryos. However, RT-PCR analysis of eleven genes, which are important regulators of cell proliferation, apoptosis, survival and angiogenesis, shows that these genes are deregulated in brain and liver tissues from SWCNTs-treated embryos in comparison with their matched controls. This study suggests that SWCNTs could have a very toxic effect on the normal development of the embryo. FROM THE CLINICAL EDITOR: In this study, a significant toxicity of single-walled carbon nanotubes was observed during normal embryogenesis: the nanotubes inhibited the angiogenesis of the chorioallantoic membrane (CAM) in chicken embryos. All exposed embryos died before 12 days of incubation, suggesting a severe effect.

Helicobacter pylori and epithelial mesenchymal transition in human gastric cancers: An update of the literature.

Gastric cancer, a multifactorial disease, is considered one of the most common malignancies worldwide. In addition to genetic and environmental risk factors, infectious agents, such as Epstein-Barr virus (EBV) and Helicobacter pylori (H.pylori) contribute to the onset and development of gastric cancer. H. pylori is a type I carcinogen that colonizes the gastric epithelium of approximately 50% of the world's population, thus increasing the risk of gastric cancer development. On the other hand, epithelial mesenchymal transition (EMT) is a fundamental process crucial to embryogenic growth, wound healing, organ fibrosis and cancer progression. Several studies associate gastric pathogen infection of the epithelium with EMT initiation, provoking cancer metastasis in the gastric mucosa through various molecular signaling pathways. Additionally, EMT is implicated in the progression and development of H. pylori-associated gastric cancer. In this review, we recapitulate recent findings elucidating the association between H. pylori infection in EMT promotion leading to gastric cancer progression and metastasis.

Coinfection of HPVs Is Associated with Advanced Stage in Colorectal Cancer Patients from Qatar.

High-risk human papillomaviruses (HPVs) are considered risk factors in the origin of several human malignancies, such as breast, cervical, head and neck, as well as colorectal cancers. However, there are no data reported on the HPV status in colorectal cancer in the State of Qatar. Therefore, we herein examined the presence of high-risk HPVs (16, 18, 31, 33, 35, 45, 51, 52, and 59), using polymerase chain reaction (PCR) in a cohort of 100 Qatari colorectal cancer patients, and their association with tumor phenotype. We found that high-risk HPV types 16, 18, 31, 35, 45, 51, 52, and 59 were present in 4, 36, 14, 5, 14, 6, 41, and 17% of our samples, respectively. Overall, 69 (69%) of the 100 samples were HPV positive; among these, 34/100 (34%) were positive for single HPV subtypes, while 35/100 (35%) of the samples were positive for two or more HPV subtypes. No significant association was noted between the presence of HPV and tumor grade, stage, or location. However, the presence of coinfection of HPV subtypes strongly correlated with advanced stage (stage 3 and 4) colorectal cancer, indicating that the copresence of more than one HPV subtype can significantly worsen the prognosis of colorectal cancer. The results from this study imply that coinfection with high-risk HPV subtypes is associated with the development of colorectal cancer in the Qatari population.

Implications of Gut Microbiota in Epithelial-Mesenchymal Transition and Cancer Progression: A Concise Review.

Advancement in the development of molecular sequencing platforms has identified infectious bacteria or viruses that trigger the dysregulation of a set of genes inducing the epithelial-mesenchymal transition (EMT) event. EMT is essential for embryogenesis, wound repair, and organ development; meanwhile, during carcinogenesis, initiation of the EMT can promote cancer progression and metastasis. Recent studies have reported that interactions between the host and dysbiotic microbiota in different tissues and organs, such as the oral and nasal cavities, esophagus, stomach, gut, skin, and the reproductive tract, may provoke EMT. On the other hand, it is revealed that certain microorganisms display a protective role against cancer growth, indicative of possible therapeutic function. In this review, we summarize recent findings elucidating the underlying mechanisms of pathogenic microorganisms, especially the microbiota, in eliciting crucial regulator genes that induce EMT. Such an approach may help explain cancer progression and pave the way for developing novel preventive and therapeutic strategies.

Quantification of the growth suppression of HER2+ breast cancer colonies under the effect of trastuzumab and PD-1/PD-L1 inhibitor.

Introduction: Immune checkpoint blockade (ICB)-based therapy is revolutionizing cancer treatment by fostering successful immune surveillance and effector cell responses against various types of cancers. However, patients with HER2+ cancers are yet to benefit from this therapeutic strategy. Precisely, several questions regarding the right combination of drugs, drug modality, and effective dose recommendations pertaining to the use of ICB-based therapy for HER2+ patients remain unanswered. Methods: In this study, we use a mathematical modeling-based approach to quantify the growth inhibition of HER2+ breast cancer (BC) cell colonies (ZR75) when treated with anti-HER2; trastuzumab (TZ) and anti-PD-1/PD-L1 (BMS-202) agents. Results and discussion: Our data show that a combination therapy of TZ and BMS-202 can significantly reduce the viability of ZR75 cells and trigger several morphological changes. The combination decreased the cell's invasiveness along with altering several key pathways, such as Akt/mTor and ErbB2 compared to monotherapy. In addition, BMS-202 causes dose-dependent growth inhibition of HER2+ BC cell colonies alone, while this effect is significantly improved when used in combination with TZ. Based on the in-vitro monoculture experiments conducted, we argue that BMS-202 can cause tumor growth suppression not only by mediating immune response but also by interfering with the growth signaling pathways of HER2+BC. Nevertheless, further studies are imperative to substantiate this argument and to uncover the potential crosstalk between PD-1/PD-L1 inhibitors and HER2 growth signaling pathways in breast cancer.

Haematococcus pluvialis Microalgae Extract Inhibits Proliferation, Invasion, and Induces Apoptosis in Breast Cancer Cells.

Breast cancer (BC) is the most common malignant cancer in females worldwide. Drug resistance, toxicity, and the failure of current therapies to completely cure BC has challenged conventional medicine. Consequently, complementary alternative medicine has become popular due to its safety and efficacy. Haematococcus pluvialis (H. pulvialis) is a green microalga living in fresh water, and its crude extract is rich of bioactives, including carotenoids, known to inhibit cancer cell growth. In the present study, we investigated the effects of a methanol crude extract called "T1" of H. pulvialis on cell growth and migration/invasion of the BC cell line MDA-MB-231 in comparison to the fibroblast control cells. TI significantly suppressed BC cell growth, inhibited migration and invasion and induced apoptosis. Interestingly, apoptosis was mediated by a significant loss of mutant p53 protein, and increased Bax/Bcl2 ratio. Our findings support our hypothesis that T1 exerts its anti-cancer effects by inhibiting BC invasion and inducing apoptosis mediated, at least, via the p53/Bax/Bcl2 pathway. Ongoing experiments aim to identify the molecular mechanisms underpinning T1-inhibited BC cell invasion using pre-designed metastasis gene-based array method.

Elaeagnus angustifolia Plant Extract Induces Apoptosis via P53 and Signal Transducer and Activator of Transcription 3 Signaling Pathways in Triple-Negative Breast Cancer Cells.

Elaeagnus angustifolia (EA) is used as an alternative medicine in the Middle East to manage numerous human diseases. We recently reported that EA flower extract inhibits cell proliferation and invasion of human oral and HER2-positive breast cancer cells. Nevertheless, the outcome of EA extract on triple-negative breast cancer (TNBC) cells has not been explored yet. We herein investigate the effect of the aqueous EA extract (100 and 200 µl/ml) on two TNBC cell lines (MDA-MB-231 and MDA-MB-436) for 48 h and explore its underlying molecular pathways. Our data revealed that EA extract suppresses cell proliferation by approximately 50% and alters cell-cycle progression of these two cancer cell lines. Additionally, EA extract induces cell apoptosis by 40-50%, accompanied by the upregulation of pro-apoptotic markers (Bax and cleaved caspase-8) and downregulation of the anti-apoptotic marker, Bcl-2. Moreover, EA extract inhibits colony formation compared to their matched control. More significantly, the molecular pathway analysis of EA-treated cells revealed that EA extract enhances p53 expression, while inhibiting the expression of total and phosphorylated Signal Transducer and Activator Of Transcription 3 (STAT3) in both cell lines, suggesting p53 and STAT3 are the main key players behind the biological events provoked by the extract in TNBC cells. Our findings implicate that EA flower extract may possess an important potential as an anticancer drug against TNBC.

Developmental Toxicity of Surface-Modified Gold Nanorods in the Zebrafish Model.

BACKGROUND: nanotechnology is one of the fastest-growing areas, and it is expected to have a substantial economic and social impact in the upcoming years. Gold particles (AuNPs) offer an opportunity for wide-ranging applications in diverse fields such as biomedicine, catalysis, and electronics, making them the focus of great attention and in parallel necessitating a thorough evaluation of their risk for humans and ecosystems. Accordingly, this study aims to evaluate the acute and developmental toxicity of surface-modified gold nanorods (AuNRs), on zebrafish (Danio rerio) early life stages. METHODS: in this study, zebrafish embryos were exposed to surface-modified AuNRs at concentrations ranging from 1 to 20 µg/mL. Lethality and developmental endpoints such as hatching, tail flicking, and developmental delays were assessed until 96 h post-fertilization (hpf). RESULTS: we found that AuNR treatment decreases the survival rate in embryos in a dose-dependent manner. Our data showed that AuNRs caused mortality with a calculated LC50 of EC50,24hpf of AuNRs being 9.1 µg/mL, while a higher concentration of AuNRs was revealed to elicit developmental abnormalities. Moreover, exposure to high concentrations of the nanorods significantly decreased locomotion compared to untreated embryos and caused a decrease in all tested parameters for cardiac output and blood flow analyses, leading to significantly elevated expression levels of cardiac failure markers ANP/NPPA and BNP/NPPB. CONCLUSIONS: our results revealed that AuNR treatment at the EC50 induces apoptosis significantly through the P53, BAX/BCL-2, and CASPASE pathways as a suggested mechanism of action and toxicity modality.