Sandra Rizk

Dr. Sandra Rizk

Lebanese American University, Beirut, Beyrouth, Lebanon
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Research Focus & Metrics

Academic Career Length

28Years (1999-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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30 October 2008 in Nutrition Journal
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Journal Article
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NYNajat Yahia
Najat Yahia
AAAlice Achkar
Alice Achkar
AAAbbass Abdallah
Abbass Abdallah
SRSandra Rizk
Sandra Rizk
Background: In the past year Lebanon has been experiencing a nutritional transition in food choices from the typical Mediterranean diet to the fast food pattern. As a consequence, the dietary habits of young adults have been affected; thus, overweight and obesity are increasingly being observed among the young. The purpose of this study is to assess the prevalence of overweight and obesity on a sample of students from the Lebanese American University (in Beirut) and to examine their eating habits. Methods: A cross-sectional survey of 220 students (43.6% male and 56.4% female), aged 20 ± 1.9 years, were chosen randomly from the Lebanese American University (LAU) campus during the fall 2006 semester. Students were asked to fill out a self-reported questionnaire that included questions on their eating, drinking and smoking habits. Also, their weight, height, percentage body fat and body mass index were measured. Body mass index (BMI) was used to assess students' weight status. Statistical analyses were performed using the Statistical Package for Social Sciences software (version 13.0) to determine overweight and obesity among students and to categorize eating habits. Results: This study showed that the majority of the students (64.7%) were of normal weight (49% male students compared to 76.8% female students). The prevalence of overweight and obesity was more common among male students compared to females (37.5% and 12.5% vs. 13.6% and 3.2%, respectively). In contrast, 6.4% female students were underweight as compared to 1% males. Eating habits of the students showed that the majority (61.4%) reported taking meals regularly. Female students showed healthier eating habits compared to male students in terms of daily breakfast intake and meal frequency. 53.3% of female students reported eating breakfast daily or three to four times per week compared to 52.1% of male students. There was a significant gender difference in the frequency of meal intake (P = 0.001). Intake of colored vegetables and fruits was common among students. A total of 30.5% reported daily intake of colored vegetables with no gender differences (31.5% females vs. 29.2% males). Alcohol intake and smoking were not common among students. Conclusion: In spite of the overall low prevalence of overweight and obesity in the studied sample, results indicate that university students would possibly benefit from a nutrition and health promotion program to reduce the tendency of overweight and obesity, especially among male students, and to improve students' eating habits.

3 September 2014 in International Journal of Oncology
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Journal Article
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NKNathalie Khoury
Nathalie Khoury
SEStephany El-Hayek
Stephany El-Hayek
OTOmayr Tarras
Omayr Tarras
MEMarwan El-Sabban
Marwan El-Sabban
MEMirvat El-Sibai
Mirvat El-Sibai
SRSandra Rizk
Sandra Rizk
Spandidos Publications is a scientific publisher with a long-standing international reputation for excellent standards and high quality science publications

19 June 2019 in Frontiers in Genetics
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AHAbdullah Hoter
Abdullah Hoter
SRSandra Rizk
Sandra Rizk
Hassan NaimHassan Naim
Hassan Naim
To cope with the extreme heat stress and drought of the desert, the Arabian camel (Camelus dromedarius) has developed exceptional physiological and biochemical particularities. Previous reports focused mainly on the physiological features of Arabian camel and neglected its cellular and molecular characteristics. Heat shock proteins are suggested to play a key role in the protein homeostasis and thermotolerance. Therefore, we aim by this review to elucidate the implication of camel HSPs in its physiological adaptation to heat stress and compare them with HSPs in related mammalian species. Correlation of these molecules to the adaptive mechanisms in camel is of special importance to expand our understanding of the overall camel physiology and homeostasis.

1 December 2020 in Biomedicine & Pharmacotherapy
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Journal Article
Open access
STStephanie Tannous
Stephanie Tannous
THTony Haykal
Tony Haykal
JDJana Dhaini
Jana Dhaini
MHMohammad Hassan Hodroj
Mohammad Hassan Hodroj
SRSandra Rizk
Sandra Rizk
Flaxseeds have been known for their anti-cancerous effects due to the high abundance of lignans released upon ingestion. The most abundant lignan, secoisolariciresinol diglucoside (SDG), is ingested during the dietary intake of flax, and is then metabolized in the gut into two mammalian lignan derivatives, Enterodiol (END) and Enterolactone (ENL). These lignans were previously reported to possess anti-tumor effects against breast, colon, and lung cancer. This study aims to investigate the potential anti-cancerous effect of the flaxseed lignans SDG, END and ENL on acute myeloid leukemia cells (AML) in vitro and to decipher the underlying molecular mechanism. AML cell lines, (KG-1 and Monomac-1) and a normal lymphoblastic cell line were cultured and treated with the purified lignans. ENL was found to be the most promising lignan, as it exhibits a significant selective dose- and time-dependent cytotoxic effect in both AML cell lines, contrary to normal cells. The cytotoxic effects observed were attributed to apoptosis induction, as revealed by an increase in Annexin V staining of AML cells with increasing ENL concentrations. The increase in the percentage of cells in the pre-G phase, in addition to cell death ELISA analysis, validated cellular and DNA fragmentation respectively. Analysis of protein expression using western blots confirmed the activation of the intrinsic apoptotic pathway upon ENL treatment. This was also accompanied by an increase in ROS production intracellularly. In conclusion, this study demonstrates that ENL has promising anti-cancer effects in AML cell lines in vitro, by promoting DNA fragmentation and the intrinsic apoptotic pathway, highlighting the protective health benefits of flax seeds in leukemia.

5 February 2016 in Planta Medica
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RKRana Khalife
Rana Khalife
MHMohammad Hassan Hodroj
Mohammad Hassan Hodroj
RFRajaa Fakhoury
Rajaa Fakhoury
SRSandra Rizk
Sandra Rizk
Topotecan, a topoisomerase I inhibitor, is an anticancer drug widely used in the therapy of lung, ovarian, colorectal, and breast adenocarcinoma. Due to the primary dose-limiting toxicity of topotecan, which is myelosuppressive, it is necessary to identify other chemotherapeutic agents that can work synergistically with topotecan to increase its efficacy and limit its toxicity. Many studies have shown synergism upon the combination of topotecan with other chemotherapeutic agents such as gemcitabine. Other studies have demonstrated that pre-exposing cells to naturally occurring compounds such as thymoquinone, followed by gemcitabine or oxaliplatin, resulted in higher growth inhibition compared to treatment with gemcitabine or oxaliplatin alone. Our aim was to elucidate the underlying mechanism of action of topotecan in the survival and apoptotic pathways in human colon cancer cell lines in comparison to thymoquinone, to study the proapoptotic and antiproliferative effects of thymoquinone on the effectiveness of the chemotherapeutic agent topotecan, and to investigate the potential synergistic effect of thymoquinone with topotecan. Cells were incubated with different topotecan and thymoquinone concentrations for 24 and 48 hours in order to determine the IC50 for each drug. Combined therapy was then tested with ± 2 values for the IC50 of each drug. The reduction in proliferation was significantly dose- and time-dependent. After determining the best combination (40 µM thymoquinone and 0.6 µM topotecan), cell proteins were extracted after treatment, and the expression levels of B-cell lymphoma 2 and of its associated X protein, proteins p53 and p21, and caspase-9, caspase-3, and caspase-8 were studied by Western blot. In addition, cell cycle analysis and annexin/propidium iodide staining were performed. Both drugs induced apoptosis through a p53-independent mechanism, whereas the expression of p21 was only seen in thymoquinone treatment. Cell cycle arrest in the S phase was detected with each compound separately, while combined treatment only increased the production of fragmented DNA. Both compounds induced apoptosis through the extrinsic pathway after 24 hours; however, after 48 hours, the intrinsic pathway was activated by topotecan treatment only. In conclusion, thymoquinone increased the effectiveness of the chemotherapeutic reagent topotecan by inhibiting proliferation and lowering toxicity through p53- and Bax/Bcl2-independent mechanisms.

16 August 2019 in Cancers
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AHAbdullah Hoter
Abdullah Hoter
SRSandra Rizk
Sandra Rizk
Hassan NaimHassan Naim
Hassan Naim
Prostate cancer (PCa) is one of the most common cancer types in men worldwide. Heat shock proteins (HSPs) are molecular chaperones that are widely implicated in the pathogenesis, diagnosis, prognosis, and treatment of many cancers. The role of HSPs in PCa is complex and their expression has been linked to the progression and aggressiveness of the tumor. Prominent chaperones, including HSP90 and HSP70, are involved in the folding and trafficking of critical cancer-related proteins. Other members of HSPs, including HSP27 and HSP60, have been considered as promising biomarkers, similar to prostate-specific membrane antigen (PSMA), for PCa screening in order to evaluate and monitor the progression or recurrence of the disease. Moreover, expression level of chaperones like clusterin has been shown to correlate directly with the prostate tumor grade. Hence, targeting HSPs in PCa has been suggested as a promising strategy for cancer therapy. In the current review, we discuss the functions as well as the role of HSPs in PCa progression and further evaluate the approach of inhibiting HSPs as a cancer treatment strategy.