An Uncommon Recurrent Metastasis of Ovarian Immature Teratoma to the Small Bowel

Immature ovarian teratomas are rare ovarian germ cell tumors associated with a variable potential of distant metastasis. The acquisition of mature phenotypes upon post-treatment recurrence of immature teratomas has been previously described. In this study, we report, for the first time, a rare case of a recurrent ovarian immature teratoma with mature deposits in the small bowel. An incidental pelvi-abdominal mass was identified in a 30-year-old pregnant patient during antenatal ultrasonography. The mass, which was resected through salpingo-oopherectomy, was histopathologically characterized as an immature teratoma of grade 2 and treated with 3 cycles of chemotherapy. After 3 years of completing treatment, the patient suffered from severe anemia which was investigated by capsule endoscopy that identified a bleeding source in the ileum. Imaging studies revealed an intrabdominal mass that was resected laparoscopically. The pathological assessment of the mass identified a submucosal/intramuscular teratoma with mature elements indicative of a recurrent metastasis of immature teratoma associated with post-chemotherapy retroconversion. The secondary mass was then managed with adjuvant chemotherapy.

Sorafenib, rapamycin, and venetoclax attenuate doxorubicin-induced senescence and promote apoptosis in HCT116 cells

Emerging evidence has shown that the therapy-induced senescent growth arrest in cancer cells is of durable nature whereby a subset of cells can reinstate proliferative capacity. Promising new drugs named senolytics selectively target senescent cells and commit them into apoptosis. Accordingly, senolytics have been proposed as adjuvant cancer treatment to cull senescent tumor cells, and thus, screening for agents that exhibit senolytic properties is highly warranted. Our study aimed to investigate three agents, sorafenib, rapamycin, and venetoclax for their senolytic potential in doxorubicin-induced senescence in HCT116 cells. HCT116 cells were treated with one of the three agents, sorafenib (5 µM), rapamycin (100 nM), or venetoclax (10 µM), in the absence or presence of doxorubicin (1 µM). Senescence was evaluated using microscopy-based and flow cytometry-based Senescence-associated-β-galactosidase staining (SA-β-gal), while apoptosis was assessed using annexin V-FITC/PI, and Muse caspase-3/-7 activity assays. We screened for potential genes through which the three drugs exerted senolytic-like action using the Human Cancer Pathway Finder PCR array. The three agents reduced doxorubicin-induced senescent cell subpopulations and significantly enhanced the apoptotic effect of doxorubicin compared with those treated only with doxorubicin. The senescence genes IGFBP5 and BMI1 and the apoptosis genes CASP7 and CASP9 emerged as candidate genes through which the three drugs exhibited senolytic-like properties. These results suggest that the attenuation of doxorubicin-induced senescence might have shifted HCT116 cells to apoptosis by exposure to the tested pharmacological agents. Our work argues for the use of senolytics to reduce senescence-mediated resistance in tumor cells and to enhance chemotherapy efficacy.

Self-Reported Obsession Toward COVID-19 Preventive Measures Among Undergraduate Medical Students During the Early Phase of Pandemic in Jordan

Background: Coronavirus disease 2019 (COVID-19) pandemic and its associated precautionary measures have substantial impacts not only on the medical, economic, and social context but also on psychological health. This study aimed to assess the obsession toward COVID-19 preventive measures among undergraduate medical students during the early phase of the pandemic in Jordan.

Methods: Online questionnaires were distributed between March 16, 2020 and March 19, 2020. Socio-demographic characteristics were collected, and self-reported obsession toward COVID-19 preventive measures was assessed using a single question.COVID-19 knowledge, risk perception, and precautionary measures were evaluated using scales. Using the chi-square test, Student t-test, and one-way ANOVA, we assessed the differences in the obsession of students with socio-demographic characteristics and scores of the scales.

Results: A total of 1,404 participants (60% were female participants) completed the survey with a participation rate of 15.6%. Obsession with preventive measures was reported by 6.8%. Obsession was significantly more common among women (9.2%) than men (3.3%) and students who attended COVID-19 lectures (9.5%) than those who did not attend such lectures (5.8%) (p < 0.001 and p = 0.015, respectively). Obsessed participants reported significantly higher levels of COVID-19 knowledge (p = 0.012) and precautionary measures (p < 0.001). COVID-19 risk perception had a mild effect size difference but with no statistical significance (p = 0.075). There were no significant differences in the academic levels of participants (p = 0.791) and universities (p = 0.807) between students who were obsessed and those who were not.

Conclusions: Obsession is one of the significant but unspoken psychological effects of COVID-19 precautionary measures among undergraduate medical students. Medical schools should be equipped with means to handle pandemic psychological effects.

Expression of Senescence and Apoptosis Biomarkers in Synchronous Bilateral Breast Cancer: A Case Report

Background: Synchronous bilateral breast cancer (SBBC) provides a special condition where two independent breast tumors are exposed to cancer pharmacotherapy within a uniform pharmacokinetic milieu. Both senescence and apoptosis are established responses to therapy; however, they have potentially variable contributions to the overall outcome of treatment, which are yet to be determined. Methods: In this report, we describe the clinicopathological picture of two SBBC cases that received standard anticancer treatment and assess their expression profile of several molecular hallmarks of senescence and apoptosis. Results: Our analysis identified that synchronous tumors have variable expression profiles of both senescence- and apoptosis-associated biomarkers, despite comparable pathological responses to neoadjuvant chemotherapy and current survival rates. Conclusions: Our results highlight the variable expression of senescence- and apoptosis-associated markers in breast tumors (despite the shared somatic genetic background) and invites a large-scale assessment of both senescence and apoptosis in breast cancer tissue in vivo and their contribution to the pathological response and overall survival.

Potential Use of Senolytics for Pharmacological Targeting of Precancerous Lesions

Senescence is a cell state that contributes to several homeostatic and pathologic processes. In addition to being induced in somatic cells in response to replicative exhaustion (replicative senescence) as part of organismal aging, senescence can also be triggered prematurely by oncogene hyperactivation or tumor suppressor dysfunction [oncogene-induced senescence (OIS)]. Consequently, senescent cells comprise a major component of precancerous lesions of skin, oral mucosa, nasopharynx, prostate, gut, and lung. Unfortunately, invasive (or minimally invasive) interventions are currently the only available approach employed to eradicate premalignant lesions that carry the potential for cancer progression. Senolytics are a newly emerging drug class capable of selectively eliminating senescent cells. Although senolytics have been successfully demonstrated to mitigate a myriad of aging-related pathologies and to cull senescent cancer cells, there is a paucity of evidence for the potential use of senolytics as a novel approach to eliminate oncogene-induced senescent cells. This Emerging Concepts commentary will 1) summarize evidence in established models of OIS including B-Raf-induced nevi, transgenic lung cancer, and pancreatic adenocarcinoma models, as well as evidence from clinical precancerous lesions; 2) suggest that OIS is targetable; and 3) propose the utilization of senolytic agents as a revolutionary means to interfere with the ability of senescent premalignant cells to progress to cancer in vitro and in vivo If proven to be effective, senolytics will represent an emerging tool to pharmacologically treat precancerous lesions. SIGNIFICANCE STATEMENT: The treatment of premalignant lesions is largely based on the utilization of invasive (or minimally invasive) measures. Oncogene-induced senescence (OIS) is one form of senescence that occurs in response to oncogene overexpression in somatic cells and is present in precancerous lesions. Although the contribution of OIS to disease progression is undetermined, recent evidence suggests that senescent cells are permissive for malignant transformation. Accordingly, the pharmacological targeting of oncogene-induced senescent cells could potentially provide a novel, less invasive, means for the treatment of premalignant disease.

Androgen-deprivation induced senescence in prostate cancer cells is permissive for the development of castration-resistance but susceptible to senolytic therapy

Prostate cancer (PCa) is one of the leading causes of cancer-related deaths in men. Although androgen deprivation therapies (ADT) and antiandrogens confer increased survival rates, most patients eventually develop castration resistant disease (CRPC). Previous studies have shown that these treatments have limited cytotoxicity, and instead, promote tumor cell growth arrest. We show here that PCa cells grown in either charcoal-stripped serum or exposed to the antiandrogen, bicalutamide, undergo a senescent growth arrest marked by morphological changes, upregulated senescence-associated-β-galactosidase (SA-β-Gal), cathepsin D accumulation, and expression of the senescence-associated secretory phenotype (SASP). The senescent growth arrest is, however, transient, as cells can resume proliferation upon restoration of normo-androgenic conditions. Intriguingly, enrichment for senescent cells confirmed that ADT-induced senescent cells recover their proliferative capacity, even under prolonged androgen deprivation, and form androgen-independent outgrowths. Transplantation of the enriched senescent population into castrated, syngeneic mice confirmed that senescent cells escape the growth arrest and form castration-resistant tumors in vivo. Outgrowth from senescence was associated with increased expression of constitutively active androgen receptor splice variants, a common mechanism of resistance to ADT. Finally, the selective elimination of senescent PCa cells following ADT in vitro by the senolytic navitoclax (ABT-263) interfered with the development of androgen-independent outgrowth. Taken together, these data support the premise that ADT-induced senescence is a transient cell state from which CRPC populations can emerge, identifying senescence as a potential driver of disease progression. Furthermore, it is feasible that senolytic therapy to eliminate senescent PCa cells could delay disease recurrence and/or progression to androgen independence.

Abstract 2024: Studying the effects of interfering with doxorubicin-induced senescence in human colon cancer HCT116 cells

Colorectal cancer (CRC) is type of cancer that growing in the colon or the rectum. Although CRC can be treated and managed through several means of therapy, the disease mortality is still high in Saudi Arabia. Upon treatment, cancer cells undergo different form of cell death or growth arrest such as apoptosis and senescence. Senescence is a state of proliferation arrest that is considered as a cause of drug resistance. The current study was designed to interfere with Doxorubicin-induced senescence in cancer cells, and shift the cytotoxicity of doxorubicin from proliferation arrest to apoptosis. β-galactosidase (β-gal) staining has demonstrated that Doxorubicin induces senescence in wild-type HCT116 but not in p21 knock-out cells. (DAPI)/TUNEL stating and Annexin V assay indicate that treatment with Doxorubicin promotes apoptosis in p21 knock-out HCT116 significantly more than in wild-type HCT116. β-galactosidase staining and 5-Dodecanoylaminofluorescein Di-β-D-Galactopyranosid (C12FDG) demonstrated that combination of Doxorubicin with Sorafenib, Rapamycin, or Venetoclax has significantly reduced senescence and induced more apoptosis as shown by Propidium iodide (PI)/Annexin v assay and Caspase 3/7 Assay. PCR data analysis demonstrated that not all combination of Doxorubicin with other agents significantly decreased expression of senescence protein, however, the results of this study provide findings that interference with senescence pathways may shift cytotoxicity from senescence to apoptosis.

The authors extend their appreciation to the Deputyship for Research and Innovation, Ministry of Education in Saudi Arabia for partly funding this work through the project number (DRI-KSU-1273).

Citation Format: Moureq Rashed Alotaibi, Homood As Sobeia, Munirah Alohaydib, Faten Alaqil, Khalid Alhazzani, Ali Alhoshani, Tareq Saleh, David Gewirtz. Studying the effects of interfering with doxorubicin-induced senescence in human colon cancer HCT116 cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2024.

Beyond knowledge: Evaluating the practices and precautionary measures towards COVID-19 amongst medical doctors in Jordan

BACKGROUND

Health Care Workers (HCWs), including medical doctors, played a pivotal role as a first-line defence against the COVID-19 pandemic. Because of high exposure, HCWs are at an increased risk of contracting the disease.

AIMS

This study aims to assess the level of precautionary measures, both at home and the workplace, amongst medical doctors who were on duty during the national lockdown in Jordan.

METHODS

A cross-sectional study was conducted between March 23 and May 1, 2020, utilising a self-administered web-based questionnaire to examine a sample of medical doctors (n = 270) working at different healthcare institutions in Jordan. Likert scale was used to code the data and generate means and percentages.

RESULTS

The most practiced on-duty precautionary measures were cleaning hands with water and disinfectant for more than 20 seconds (47.4%), followed by proper hygiene before and during meals (38.9%). The most practiced off-duty measures were taking off clothes before entering the residential place (65.9%) and prohibiting visitors (58.1%). Overall, the mean work protection percentage score was 73.8% (range: 28%-100%), while the mean home safety percentage score was 71.3% (range: 25%-100%). Work protection score was positively correlated with the home safety score. Female doctors were found to be more precautious at home than males. Doctors with chronic illness(es) were found to be less precautious than their healthier counterparts. Participants who isolated themselves expressed the highest level of home safety practice. Doctors who reported to smoke were found more precautious at home and doctors who preferred to work during lockdowns were more precautious at the workplace.

CONCLUSION

The level of precautionary behaviour of medical doctors in Jordan was not optimal. More attention and efforts are needed to enhance the adherence of doctors to precautionary guidance. Strengthening the role of infectious disease and infection control units within healthcare settings remains a necessity.

Expression of therapy-induced senescence markers in breast cancer samples upon incomplete response to neoadjuvant chemotherapy

Senescence is a cell stress response induced by replicative, oxidative, oncogenic, and genotoxic stresses. Tumor cells undergo senescence in response to several cancer therapeutics in vitro (Therapy-Induced Senescence, TIS), including agents utilized as neoadjuvant chemotherapy (NAC) in the treatment of invasive breast cancer. TIS has been proposed to contribute to adverse therapy outcomes including relapse. However, there is limited evidence on the induction of senescence in response to NAC in clinical cancer and its contribution to disease outcomes. In this work, the expression of three senescence-associated markers (p21CIP1, H3K9Me3 (histone H3 lysine 9 trimethylation), and Lamin B1) was investigated in breast cancer samples that developed partial or incomplete pathological response to NAC (n=37). Accordingly, 40.54% of all samples showed marker expression consistent with a senescence-like phenotype, while the remainders were either negative or inconclusive for senescence (2.70 and 56.8%, respectively). Moreover, analysis of core-needle biopsies revealed minimal changes in p21CIP1 and H3K9Me3, but significant changes in Lamin B1 expression levels following NAC, highlighting a more predictive role of Lamin B1 in senescence detection. However, our analysis did not establish an association between TIS and cancer relapse as only three patients (8.1%) with a senescence-like profile developed short-term recurrent disease. Our analysis indicates that identification of TIS in tumor samples requires large-scale transcriptomic and protein marker analyses and extended clinical follow-up. Better understanding of in vivo senescence should elucidate its contribution to therapy outcomes and pave the way for the utilization of senolytic approaches as potential adjuvant cancer therapy.

Functional Characterization of the Orphan Nuclear Receptor TLX in Triple Negative Breast Cancer

Despite the development of various therapeutic strategies, breast cancer persists as the second leading cause of cancer-related death among women in the United States. While endocrine modulation and monoclonal antibody therapy have proved to be indispensable modes of intervention for hormone receptor (HR)-positive and HER-2 positive patients, the triple negative breast cancer (TNBC) patient population do not respond to these therapies. As TNBC is considered one of the most challenging subtypes of breast cancer to treat, there is a significant need for the development of targeted therapeutics. Due to their well-known amenability to small-molecule modulation, we investigated whether any nuclear receptors beyond those that are traditionally studied in breast cancer (e.g. ER, PR, and AR), may represent a novel target in the TNBC patient population. Analysis of clinical data revealed that expression of the orphan nuclear receptor TLX (NR2E1) was positively correlated with relapse-free survival, distant metastasis-free survival, and overall survival in both ER-negative and basal-like breast cancer patients. Therefore, we hypothesized that TLX could influence the pathophysiology of TNBC. To interrogate this hypothesis, we established TNBC cells with stable expression of TLX in order to identify direct regulatory targets, as well as the precise physiological mechanism(s) TLX may be regulating. To date, our work has revealed that TLX inhibits proliferation, slows migration, alters chemosensitivity, and impairs cell cycle progression in TNBC cells. In agreement with these findings, our work has also revealed that TLX is capable of modulating the expression of several genes that are known to regulate the processes of growth, migration, and cell cycle. Taken together, our early work supports our hypothesis, and provides valuable insight into the potential pro-survival function of TLX in TNBC. Ongoing work will continue to probe the mechanisms by which TLX impacts breast cancer biology, and establish whether the growth-inhibitory effects translate to in vivo models. As prior work has demonstrated that TLX’s transcriptional activity can be regulated by both synthetic and natural ligands, the results of our work would provide the foundational data necessary for the development of a TLX-based therapy for a patient population with limited therapeutic options and a poor prognostic outlook.

Medical students' relative immunity, or lack thereof, against COVID-19 emotional distress and psychological challenges; a descriptive study from Jordan

Background: Emotional distress is a major impact of COVID-19 among not only the general public but also healthcare workers including medical students. This study aimed at describing self-reported changes in emotional reactions associated with COVID-19 among medical students in Jordan and to assessing the potential effect of social media utilization on emotional distress among this group. Methods: A cross-sectional design was utilized to collect data early on during the outbreak in Jordan. All medical students in Jordan were eligible to complete an online questionnaire assessing self-reported emotional reactions to COVID-19 that covered four main domains: negative emotion (anxiety, worry, depression, panic, loneliness, and nervousness), positive emotion (happiness, joy, and excitement), sleep disorders (insomnia, shallow sleep, nightmares, and insufficient sleep), and aggression (verbal argument and physical fighting). The frequency of social media utilization as a main source of COVID-19 information was also assessed. Results: 59.9% of participants were females, 64.9% were enrolled at the two major medical schools in Jordan, and 59.6% were in the pre-clinical stage (years). A significant proportion of participants self-reported increased negative emotional levels of anxiety (49.2%), worry (72.4%), depression (23.1%), panic (22.6%), and nervousness (38.2%) and decreased positive emotional levels of happiness (44.8%), joy (47.3%), and feelings of excitement (45.1%). Self-reported sleep disorders were not as common (less than 15% for any of the four items), while arguing with others was at 26.7%. Significant differences by gender and academic year were detected. Almost half of participants reported using social media as a main source of COVID-19 information "most/all-the-times" with a significant effect of such on reducing emotional distress. Conclusion: The results suggest a potential effect of COVID-19 on the emotional distress of medical students. Addressing and mitigating such effects is crucial. The potential buffering effect of social media should be further investigated.

Autophagy and senescence in cancer therapy

Tumor cells can undergo diverse responses to cancer therapy. While apoptosis represents the most desirable outcome, tumor cells can alternatively undergo autophagy and senescence. Both autophagy and senescence have the potential to make complex contributions to tumor cell survival via both cell autonomous and cell non-autonomous pathways. The induction of autophagy and senescence in tumor cells, preclinically and clinically, either individually or concomitantly, has generated interest in the utilization of autophagy modulating and senolytic therapies to target autophagy and senescence, respectively. This chapter summarizes the current evidence for the promotion of autophagy and senescence as fundamental responses to cancer therapy and discusses the complexity of their functional contributions to cell survival and disease outcomes. We also highlight current modalities designed to exploit autophagy and senescence in efforts to improve the efficacy of cancer therapy.

Clearance of therapy-induced senescent tumor cells by the senolytic ABT-263 via interference with BCL-XL -BAX interaction

Tumor cells undergo senescence in response to both conventional and targeted cancer therapies. The induction of senescence in response to cancer therapy can contribute to unfavorable patient outcomes, potentially including disease relapse. This possibiliy is supported by our findings that tumor cells induced into senescence by doxorubicin or etoposide can give rise to viable tumors in vivo. We further demonstrate sensitivity of these senescent tumor cells to the senolytic ABT-263 (navitoclax), therefore providing a "two-hit" approach to eliminate senescent tumor cells that persist after exposure to chemotherapy or radiation. The sequential combination of therapy-induced senescence and ABT-263 could shift the response to therapy toward apoptosis by interfering with the interaction between BCL-XL and BAX. The administration of ABT-263 after either etoposide or doxorubicin also resulted in marked, prolonged tumor suppression in tumor-bearing animals. These findings support the premise that senolytic therapy following conventional cancer therapy may improve therapeutic outcomes and delay disease recurrence.

Senescence and castration resistance in prostate cancer: A review of experimental evidence and clinical implications

The development of Castration-Resistant Prostate Cancer (CRPC) remains a major challenge in the treatment of this disease. While Androgen Deprivation Therapy (ADT) can result in tumor shrinkage, a primary response of Prostate Cancer (PCa) cells to ADT is a senescent growth arrest. As a response to cancer therapies, senescence has often been considered as a beneficial outcome due to its association with stable growth abrogation, as well as the potential for immune system activation via the Senescence-Associated Secretory Phenotype (SASP). However, there is increasing evidence that not only can senescent cells regain proliferative capacity, but that senescence contributes to deleterious effects of cancer chemotherapy, including disease recurrence. Notably, the preponderance of work investigating the consequences of therapy-induced senescence on tumor progression has been performed in non-PCa models. Here, we summarize the evidence that ADT promotes a senescent response in PCa and postulate mechanisms by which senescence may contribute to the development of castration-resistance. Primarily, we suggest that ADT-induced senescence may support CRPC development via escape from senescence, by cell autonomous-reprogramming, and by the formation of a pro-tumorigenic SASP. However, due to the scarcity of direct evidence from PCa models, the consequences of ADT-induced senescence outlined here remain speculative until the relationship between senescence and CRPC can be experimentally defined.

Abstract 5831: Clearance of therapy-induced senescent cancer cells by the senolytic ABT-263 in a model of non-small cell lung cancer

While most chemotherapies will initially lead to tumor reduction in patients, residual tumor cells that enter a state of dormancy can re-emerge as aggressive, recurrent disease after treatment is terminated. One mechanism by which cancer cells may escape chemotherapy-induced death is senescence. Senescence is a specialized form of cell cycle arrest that is primarily characterized as a durable, prolonged loss of proliferative capacity. While senescence was traditionally considered to be irreversible, evidence has accumulated in recent years supporting the premise that senescence is instead a durable form of growth arrest from which a subpopulation of cells can ultimately escape. Moreover, the accumulation of senescent cells post cancer therapy has been linked with a plethora of unfavorable outcomes. A sequential approach in which chemotherapy is followed by a senolytic, an emerging class of drugs that selectively kill senescent cells, may therefore delay or circumvent recurrent disease by eliminating residual senescent cells. To this end, we tested whether etoposide- or radiation-treated non-small cell lung cancer (NSCL) cells become susceptible to the BH-3 mimetic ABT-263– an established senolytic– following senescence induction. Treatment with etoposide or radiation induced a robust senescent state, as evidenced by the development of multiple senescent phenotypes. Senescent tumor cells demonstrated increased sensitivity to ABT-263 compared to non-senescent cells, undergoing rapid apoptosis subsequent to ABT-263 exposure. We further determined that ABT-263's mechanism of action appears to depend upon the disruption of the BCL-XL/Bax interaction. ABT-263's capacity to eliminate senescent cells is conserved in vivo, as tumor-bearing animals treated with etoposide followed by ABT-263 undergo rapid tumor reduction followed by tumor maintenance, while etoposide-only treated animals develop progressive disease subsequent to treatment completion. These data support the use of senolytics as complementary therapy to eliminate residual tumor cells following chemotherapy or radiation, and thereby potentially delay or reduce recurrent disease.

Citation Format: Valerie Carpenter, Tareq Saleh, David Gewirtz. Clearance of therapy-induced senescent cancer cells by the senolytic ABT-263 in a model of non-small cell lung cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5831.

Analgesic Effects and Impairment in Locomotor Activity Induced by Cannabinoid/Opioid Combinations in Rat Models of Chronic Pain

Both opioids and cannabinoids have well-known antinociceptive effects in different animal models of chronic pain. However, unwanted side effects limit their use. The aim of this study is to evaluate the antinociceptive effect of combining synthetic cannabinoids with subtherapeutic doses of opioids, and to evaluate the effects of these drugs/combinations on rat’s locomotor activity. Intra-plantar injection of Complete Freund’s Adjuvant (CFA) into the left hindpaw and intraperitoneal injection of streptozotocin (STZ) were used to induce inflammatory and diabetic neuropathic pain in adult male Sprague-Dawley rats, respectively. Von Frey filaments were used to assess the antinociceptive effects of opioids (morphine and tramadol) and the synthetic cannabinoids (HU210 and WIN55212) or their combinations on CFA and STZ-induced mechanical allodynia. Open field test was used to evaluate the effect of these drugs or their combinations on locomotion. HU210 and WIN55212 did not produce significant antinociceptive effect on inflammatory pain while only the maximal dose of HU210 (1 mg/kg) was effective in neuropathic pain. Only the maximal doses of morphine (3.2 mg/kg) and tramadol (10 mg/kg) had significant anti-allodynic effects in both models. Tramadol (1 mg/kg) enhanced the antinociceptive effects of WIN55212 but not HU210 in neuropathic pain with no effect on inflammatory pain. However, in open field test, the aforementioned combination did not change tramadol-induced depression of locomotion. Tramadol and WIN55212 combination produces antinociceptive effects in neuropathic but not inflammatory pain at low doses with no additional risk of locomotor impairment, which may be useful in clinical practice.

Status of Biofilm-Forming Genes among Jordanian Nasal Carriers of Methicillin-Sensitive and Methicillin-Resistant Staphylococcus aureus

Introduction:

Biofilm formation in Staphylococcusaureus is a major virulence factor. Both MSSA and MRSA are common causes of community- and hospital-acquired infections and are associated with biofilm formation. The status of biofilm-forming genes has not been explored in Jordanian nasal carriers of S. aureus. This study investigates antibiotic resistance patterns and the prevalence of biofilm-forming genes between MSSA and MRSA in two distinct populations in Jordan.

Methods:

A total of 35 MSSA and 22 MRSA isolates were recovered from hospitalized patients and medical students at Prince Hamzah Hospital, Jordan. Antibiotic susceptibility was tested using disk diffusion method and Vitek 2 system. The phenotypic biofilm formation was tested using CRA and microtiter plate assays. The prevalence of the biofilm-forming genes was determined using multiplex PCR.

Results:

Among 57 S.aureus isolates, 22 (38.6%) isolates were MRSA and were highly resistant against benzylpenicillin, oxacillin, and imipenem. The frequencies of the icaADBC were 77.1%, 97.1%, 94.3%, and 97.1% respectively in MSSA compared to 86.4%, 100%, 100%, and 100% in MRSA isolates. On the other hand, the frequency of the fnbA, fnbB, clfA, fib, clfB, ebps, eno, and cna genes was 81.8%, 90.9%, 95.5%, 90.9%, 86.4%, 100%, 100%, and 40.9%, respectively in the MRSA isolates.

Conclusion:

In both groups, MRSA isolates, in comparison to MSSA, were significantly more resistant to cefoxitin, oxacillin, imipenem, tetracycline, clindamycin, and trimethoprim-sulfamethoxazole. Unexpectedly, biofilm formation and gene prevalence between MRSA and MSSA isolates showed no significant difference, suggesting other potential virulence mechanisms.

Medical Students and COVID-19: Knowledge, Attitudes, and Precautionary Measures. A Descriptive Study From Jordan

The recent coronavirus disease (COVID-19) pandemic is associated with increasing morbidity and mortality and has impacted the lives of the global populations. Human behavior and knowledge assessment during the crisis are critical in the overall efforts to contain the outbreak. To assess knowledge, attitude, perceptions, and precautionary measures toward COVID-19 among a sample of medical students in Jordan. This is a cross-sectional descriptive study conducted between the 16th and 19th of March 2020. Participants were students enrolled in different levels of study at the six medical schools in Jordan. An online questionnaire which was posted on online platforms was used. The questionnaire consisted of four main sections: socio-demographics, sources of information, knowledge attitudes, and precautionary measures regarding COVID-19. Medical students used mostly social media (83.4%) and online search engines (84.8%) as their preferred source of information on COVID-19 and relied less on medical search engines (64.1%). Most students believed that hand shaking (93.7%), kissing (94.7%), exposure to contaminated surfaces (97.4%), and droplet inhalation (91.0%) are the primary mode of transmission but were indecisive regarding airborne transmission with only 41.8% in support. Participants also reported that elderly with chronic illnesses are the most susceptible group for the coronavirus infection (95.0%). As a response to the COVID-19 pandemic more than 80.0% of study participants adopted social isolation strategies, regular hand washing, and enhanced personal hygiene measures as their first line of defense against the virus. In conclusion, Jordanian medical students showed expected level of knowledge about the COVID-19 virus and implemented proper strategies to prevent its spread.

Prevalence of Human Papillomavirus Associated with Head and Neck Squamous Cell Carcinoma in Jordanian Patients

Background:

In addition to smoking and alcohol consumption, human papillomavirus (HPV) is a leading etiology for Head and Neck Squamous Cell Carcinoma (HNSCC). However, this causal association is still understudied in Middle Eastern populations.

Objective:

The aim of this study was to determine the prevalence of HPV-associated infection in the Jordanian HNSCC patients and the associated HPV genotypes.

Methods:

Formalin-Fixed Paraffin-Embedded (FFPE) squamous cell carcinoma samples of the head and neck were collected from two referral centers in Amman, Jordan to determine the existence of HPV DNA. After DNA extraction HPV infection and genotyping were identified using real-time PCR.

Results:

HPV DNA was detected in 19 out of 61 (31.1%) HNSCC samples. Despite screening for 28 different genotypes, HPV 16 was the only genotype identified in all examined samples. Most HPV-positive samples were obtained from the oropharynx (41.7%), oral cavity (37%), and larynx (18.2%). No significant association between HPV 16 genotype and age, sex, tobacco use, anatomical location, or tumor grade was noticed.

Conclusion:

This study reported a high association between HPV 16 genotype and HNSCC in Jordanian patients. These data should facilitate the implementation of appropriate HPV awareness campaigns, and activate selective prophylactic measures against HPV infection.

Therapy-Induced Senescence: An "Old" Friend Becomes the Enemy

For the past two decades, cellular senescence has been recognized as a central component of the tumor cell response to chemotherapy and radiation. Traditionally, this form of senescence, termed Therapy-Induced Senescence (TIS), was linked to extensive nuclear damage precipitated by classical genotoxic chemotherapy. However, a number of other forms of therapy have also been shown to induce senescence in tumor cells independently of direct genomic damage. This review attempts to provide a comprehensive summary of both conventional and targeted anticancer therapeutics that have been shown to induce senescence in vitro and in vivo. Still, the utility of promoting senescence as a therapeutic endpoint remains under debate. Since senescence represents a durable form of growth arrest, it might be argued that senescence is a desirable outcome of cancer therapy. However, accumulating evidence suggesting that cells have the capacity to escape from TIS would support an alternative conclusion, that senescence provides an avenue whereby tumor cells can evade the potentially lethal action of anticancer drugs, allowing the cells to enter a temporary state of dormancy that eventually facilitates disease recurrence, often in a more aggressive state. Furthermore, TIS is now strongly connected to tumor cell remodeling, potentially to tumor dormancy, acquiring more ominous malignant phenotypes and accounts for several untoward adverse effects of cancer therapy. Here, we argue that senescence represents a barrier to effective anticancer treatment, and discuss the emerging efforts to identify and exploit agents with senolytic properties as a strategy for elimination of the persistent residual surviving tumor cell population, with the goal of mitigating the tumor-promoting influence of the senescent cells and to thereby reduce the likelihood of cancer relapse.

Influence of nonprotective autophagy and the autophagic switch on sensitivity to cisplatin in non-small cell lung cancer cells

While therapy-induced autophagy is conventionally conceived to be cytoprotective in nature, previous studies have identified multiple functions of autophagy, including a nonprotective form, as well as the existence of a switch between the different forms of autophagy. The current work provides further evidence of an autophagic switch, in this case in response to the antitumor drug, cisplatin, in non-small cell lung cancer cells that are either wild-type (p53wt) or functionally null in p53 (crp53), the latter generated using CRISPR/Cas9 technology. Pharmacological and genetic inhibition of autophagy identified nonprotective autophagy in p53wt cells and cytoprotective autophagy in crp53 cells. Furthermore, differences in cisplatin sensitivity between the two cell lines proved to be largely a function of the nature of the autophagy. Specifically, autophagy inhibition in the crp53 cells converts the temporal profile for the loss of cell viability in response to cisplatin to essentially parallel that observed in the p53wt cells. This enhanced sensitivity is due to cisplatin-induced apoptosis that occurs without necessitating the restoration of functional p53. In contrast, inhibition of autophagy has no observable impact on the temporal response profile exhibited in response to cisplatin in the p53wt cells, or the extent of cisplatin-induced apoptosis in the p53wt cells, consistent with the functional definition of nonprotective autophagy. Taken together, our current studies provide evidence that nonprotective autophagy in p53wt non-small cell lung cancer cells can be "switched" to protective autophagy in isogenic crp53 cells, and furthermore that inhibition of cytoprotective autophagy is sufficient to restore cisplatin sensitivity in the crp53 cells, largely through the increased promotion of apoptosis, despite the absence of functional p53.

Medical Students and COVID-19: Knowledge, Attitudes, and Precautionary Measures. A Descriptive Study From Jordan

The recent coronavirus disease (COVID-19) pandemic is associated with increasing morbidity and mortality and has impacted the lives of the global populations. Human behavior and knowledge assessment during the crisis are critical in the overall efforts to contain the outbreak. To assess knowledge, attitude, perceptions, and precautionary measures toward COVID-19 among a sample of medical students in Jordan. This is a cross-sectional descriptive study conducted between the 16th and 19th of March 2020. Participants were students enrolled in different levels of study at the six medical schools in Jordan. An online questionnaire which was posted on online platforms was used. The questionnaire consisted of four main sections: socio-demographics, sources of information, knowledge attitudes, and precautionary measures regarding COVID-19. Medical students used mostly social media (83.4%) and online search engines (84.8%) as their preferred source of information on COVID-19 and relied less on medical search engines (64.1%). Most students believed that hand shaking (93.7%), kissing (94.7%), exposure to contaminated surfaces (97.4%), and droplet inhalation (91.0%) are the primary mode of transmission but were indecisive regarding airborne transmission with only 41.8% in support. Participants also reported that elderly with chronic illnesses are the most susceptible group for the coronavirus infection (95.0%). As a response to the COVID-19 pandemic more than 80.0% of study participants adopted social isolation strategies, regular hand washing, and enhanced personal hygiene measures as their first line of defense against the virus. In conclusion, Jordanian medical students showed expected level of knowledge about the COVID-19 virus and implemented proper strategies to prevent its spread.

Antinociceptive and Abuse Potential Effects of Cannabinoid/Opioid Combinations in a Chronic Pain Model in Rats

Chronic pain is a persistent and debilitating health problem. Although the use of analgesics such as opioids is useful in mitigating pain, their prolonged use is associated with unwanted effects including abuse liability. This study assesses the antinociceptive effect of combining subtherapeutic doses of two opioids (morphine or tramadol) with the synthetic cannabinoid CP55940 (2-[(1R,2R,5R)-5-hydroxy-2-(3-hydroxypropyl)cyclohexyl]-5-(2-methyloctan -2-yl)phenol). It also evaluates the associated adverse effects of these drugs and combinations. Adult male rats were injected with intraplantar complete Freund’s adjuvant (CFA) to produce mechanical allodyia. Antinociceptive effect of morphine, tramadol, the synthetic cannabinoid CP55940, or their combinations was evaluated three to nine days post-CFA injections. Intracranial self-stimulation (ICSS) was utilized to evaluate the abuse liability of these drugs or their combinations. All drugs alone produced a dose-dependent antinociceptive effect. Morphine produced minimal effect on ICSS, but both tramadol and CP55940 produced dose-dependent depression of ICSS. Morphine at a dose of 0.32 mg/kg enhanced the antinociceptive effects of CP55940, in that, CP55940 produced antinociception at a lower dose (0.1 mg/kg) when compared to the vehicle. The aforementioned combinations did not change CP55940-induced depression of ICSS. On the other hand, tramadol failed to enhance the antinociceptive effect of CP55940. Our data suggest that combining CP55940 with morphine, but not tramadol, shows a better antinociceptive profile with no additional risk of abuse liability, which represents a potential pain management approach.

Abstract 4278: A comparison of drug sensitivity in isogenic tumor cell lines confirms that cytoprotective autophagy confers intrinsic resistance to cisplatin

Although autophagy inhibition often increases tumor cell sensitivity to chemotherapy and radiation, these observations do not provide definitive proof that autophagy is actually an intrinsic mechanism of resistance since virtually all tumor cells undergo autophagy in response to therapy. To directly address whether autophagy induction can confer chemoresistance, the current studies utilized a paired set of isogenic cell lines in which (cisplatin-induced) autophagy was either cytoprotective (crp53 cells where p53 was knocked out) or nonprotective (parental p53 wt cells) in function, but where the overall extent of autophagy was essentially identical. Cisplatin sensitivity was significantly lower in the crp53 cells where cisplatin-induced autophagy was protective compared to the parental p53 wt cells where cisplatin-induced autophagy was nonprotective, in support of the premise that cytoprotective autophagy could confer a relative degree of intrinsic resistance to chemotherapy. Accordingly, we can draw the following conclusions: (i) radiation and chemotherapy can promote both protective and nonprotective autophagy in tumor cells; (ii) although p53 can act as an autophagic switch, it cannot be reliably predicted whether autophagy will be protective or nonprotective based solely on p53 function; and (iii) even in the case(s) where autophagy is cytoprotective, it cannot be assumed that autophagy will confer drug or radiation resistance, but only that autophagy inhibition may, in select cases, increase drug or radiation sensitivity. These findings highlight the complexity of efforts to exploit autophagy inhibition as a therapeutic strategy to enhance tumor response to chemotherapy and radiation.

Citation Format: Jingwen Xu, Nipa Patel, Tareq Saleh, Yingliang Wu, Santiago Lima, David A. Gewirtz. A comparison of drug sensitivity in isogenic tumor cell lines confirms that cytoprotective autophagy confers intrinsic resistance to cisplatin [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4278.

Abstract 901: Elimination of senescent tumor cells by ABT263 interferes with proliferative recovery and provides a two-hit therapeutic approach

Senescence represents a fundamental response to cancer therapy. Accumulating senescent cells contribute to the deleterious outcomes of cancer therapy including cancer relapse, effects that may be largely mediated by the Senescence-Associated Secretory Phenotype (SASP). In this work, we show that tumor cells induced into senescence by etoposide retain proliferative capacity based on their capacity to generate proliferating colonies in culture as well as giving rise to viable tumors in vivo. Using a flow cytometry-based enrichment approach based on enlarged size and expression of Senescence-Associated β-galactosidase (SA-β-gal), we were able to utilize real time imaging to establish the re-emergence of non-small cell lung cancer cells from senescence-based arrest and the generation or proliferating daughter cells (i.e. self-renewal). Moreover, we implemented High-Speed Live-Cell Interferometry (HSLCI) to provide a single-cell lineage tracking of dividing senescent cells. The recovery from senescence was accompanied by resolution of several senescence-associated hallmarks, specifically SA-β-gal activity, p21Waf1/Cip1 and several components of the SASP (IL-1β, IL-6 and CXCL1). Our data suggests that Therapy-Induced Senescence (TIS) may ultimately be a transient process in that at least a subpopulation of tumor cells can recover proliferative capacity. We further demonstrate that the senolytic agent, ABT263, which has been shown to eliminate senescent cells from aging-related animal models can also eliminate senescent tumor cells that persistent after exposure to chemotherapy by shifting the response towards apoptotic cell death. Furthermore, sequential administration of ABT263 interferes with the ability of tumor cells induced into senescence by chemotherapy to recover growth potential. These studies suggest that senescent tumor cells can potentially contribute to cancer relapse by acquiring proliferative properties. The use of senolytic agents after induction of senescence by conventional or targeted therapies allows for the clearance of residual (possibly dormant) senescent tumor cells, which could serve to suppress disease recurrence and cancer mortality.

Citation Format: Tareq Saleh, Liliya Tyutyunyk-Massey, Graeme F. Murray, Moureq R. Alotaibi, Ajinkya S. Kawale, Zeinab Elsayed, Scott C. Henderson, Vasily Yakovlev, Lynne W. Elmore, Amir Toor, Hisashi Harada, Jason Reed, Joseph W. Landry, David A. Gewirtz. Elimination of senescent tumor cells by ABT263 interferes with proliferative recovery and provides a two-hit therapeutic approach [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 901.