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Circulating tumor cells (CTCs) are cells released from the primary and metastatic tumor and intravasate into the blood or lymphatic vessels, where they are transported to distant sites and act as seeds that initiate cancer metastases or the development of further lesions. Recent advances in CTC research have shown their relevance as prognostic markers for early and metastatic disease detection, predictive biomarkers for relapse, and response to medical intervention or therapy. The rapidly evolving landscape of CTC biology has opened new avenues for understanding cancer progression, metastasis, and treatment response. Additionally, translating these findings into clinical applications holds promise for improving cancer diagnostics, prognosis, and personalized therapeutic strategies. This review discusses the significance of CTCs in cancer research and their associated challenges. We explore recent developments in the detection and characterization of CTCs and their implications in cancer research and clinical practice.
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ABSTRACT: Pancreatic cancer remains one of the deadliest of all cancer types with a 5-year overall survival rate of just 12%. Preclinical models available for understanding the disease pathophysiology have evolved significantly in recent years. Traditionally, commercially available 2-dimensional cell lines were developed to investigate mechanisms underlying tumorigenesis, metastasis, and drug resistance. However, these cells grow as monolayer cultures that lack heterogeneity and do not effectively represent tumor biology. Developing patient-derived xenografts and genetically engineered mouse models led to increased cellular heterogeneity, molecular diversity, and tissues that histologically represent the original patient tumors. However, these models are relatively expensive and very timing consuming. More recently, the advancement of fast and inexpensive in vitro models that better mimic disease conditions in vivo are on the rise. Three-dimensional cultures like organoids and spheroids have gained popularity and are considered to recapitulate complex disease characteristics. In addition, computational genomics, transcriptomics, and metabolomic models are being developed to simulate pancreatic cancer progression and predict better treatment strategies. Herein, we review the challenges associated with pancreatic cancer research and available analytical models. We suggest that an integrated approach toward using these models may allow for developing new strategies for pancreatic cancer precision medicine.
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Neoplasias Pancreáticas , Camundongos , Animais , Humanos , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patologia , Modelos Animais de Doenças , Carcinogênese , Organoides/patologia , Pâncreas/patologiaRESUMO
In humans, the glutathione S-transferases (GST) protein family is composed of seven members that present remarkable structural similarity and some degree of overlapping functionalities. GST proteins are crucial antioxidant enzymes that regulate stress-induced signaling pathways. Interestingly, overactive GST proteins are a frequent feature of many human cancers. Recent evidence has revealed that the biology of most GST proteins is complex and multifaceted and that these proteins actively participate in tumorigenic processes such as cell survival, cell proliferation, and drug resistance. Structural and pharmacological studies have identified various GST inhibitors, and these molecules have progressed to clinical trials for the treatment of cancer and other diseases. In this review, we discuss recent findings in GST protein biology and their roles in cancer development, their contribution in chemoresistance, and the development of GST inhibitors for cancer treatment.
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Pancreatic ductal adenocarcinoma (PDAC), a metabolic disorder, remains one of the leading cancer mortality sources worldwide. An initial response to treatments, such as gemcitabine (GEM), is often followed by emergent resistance reflecting an urgent need for alternate therapies. The PDAC resistance to GEM could be due to ERK1/2 activity. However, successful ERKi therapy is hindered due to low ligand efficiency, poor drug delivery, and toxicity. In this study, to overcome these limitations, we have designed pH-responsive nanoparticles (pHNPs) with a size range of 100-150 nm for the simultaneous delivery of ERKi (SCH 772984) and GEM with tolerable doses. These pHNPs are polyethylene glycol (PEG)-containing amphiphilic polycarbonate block copolymers with tertiary amine side chains. They are systemically stable and capable of improving in vitro and in vivo drug delivery at the cellular environment's acidic pH. The functional analysis indicates that the nanomolar doses of ERKi or GEM significantly decreased the 50% growth inhibition (IC50) of PDAC cells when encapsulated in pHNPs compared to free drugs. The combination of ERKi with GEM displayed a synergistic inhibitory effect. Unexpectedly, we uncover that the minimum effective dose of ERKi significantly promotes GEM activities on PDAC cells. Furthermore, we found that pHNP-encapsulated combination therapy of ERKi with GEM was superior to unencapsulated combination drug therapy. Our findings, thus, reveal a simple, yet efficient, drug delivery approach to overcome the limitations of ERKi for clinical applications and present a new model of sensitization of GEM by ERKi with no or minimal toxicity.
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Proliferação de Células/efeitos dos fármacos , Desoxicitidina/análogos & derivados , Portadores de Fármacos/química , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Nanopartículas/química , Neoplasias Pancreáticas/tratamento farmacológico , Inibidores de Proteínas Quinases/administração & dosagem , Animais , Apoptose/efeitos dos fármacos , Carcinoma Ductal Pancreático/tratamento farmacológico , Linhagem Celular Tumoral , Desoxicitidina/administração & dosagem , Desoxicitidina/química , Sistemas de Liberação de Medicamentos/métodos , Feminino , Humanos , Concentração de Íons de Hidrogênio , Masculino , Camundongos , Camundongos Nus , Polietilenoglicóis/química , Polímeros/química , Inibidores de Proteínas Quinases/química , Ensaios Antitumorais Modelo de Xenoenxerto/métodos , GencitabinaRESUMO
Glutathione S-transferase pi-1 (GSTP1) plays an important role in regulating oxidative stress by conjugating glutathione to electrophiles. GSTP1 is overexpressed in breast, colon, lung, and prostate tumors, where it contributes to tumor progression and drug resistance; however, the role of GSTP1 in pancreatic ductal adenocarcinoma (PDAC) is not well understood. Using shRNA, we knocked down GSTP1 expression in three different PDAC cell lines and determined the effect on cell proliferation, cell cycle progression, and reactive oxygen species (ROS) levels. Our results show GSTP1 knockdown reduces PDAC cell growth, prolongs the G0/G1 phase, and elevates ROS in PDAC cells. Furthermore, GSTP1 knockdown results in the increased phosphorylation of c-Jun N-terminal kinase (JNK) and c-Jun and the decreased phosphorylation of extracellular signal-regulated kinase (ERK), p65, the reduced expression of specificity protein 1 (Sp1), and the increased expression of apoptosis-promoting genes. The addition of the antioxidant glutathione restored cell viability and returned protein expression levels to those found in control cells. Collectively, these data support the working hypothesis that the loss of GSTP1 elevates oxidative stress, which alters mitogen-activated protein (MAP) kinases and NF-κB signaling, and induces apoptosis. In support of these in vitro data, nude mice bearing orthotopically implanted GSTP1-knockdown PDAC cells showed an impressive reduction in the size and weight of tumors compared to the controls. Additionally, we observed reduced levels of Ki-67 and increased expression of cleaved caspase-3 in GSTP1-knockdown tumors, suggesting GSTP1 knockdown impedes proliferation and upregulates apoptosis in PDAC cells. Together, these results indicate that GSTP1 plays a significant role in PDAC cell growth and provides support for the pursuit of GSTP1 inhibitors as therapeutic agents for PDAC.
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Several challenges present themselves when discussing current approaches to the prevention or treatment of pancreatic cancer. Up to 45% of the risk of pancreatic cancer is attributed to unknown causes, making effective prevention programs difficult to design. The most common type of pancreatic cancer, pancreatic ductal adenocarcinoma (PDAC), is generally diagnosed at a late stage, leading to a poor prognosis and 5-year survival estimate. PDAC tumors are heterogeneous, leading to many identified cell subtypes within one patient's primary tumor. This explains why there is a high frequency of tumors that are resistant to standard treatments, leading to high relapse rates. This review will discuss how epigenetic technologies and epigenome-wide association studies have been used to address some of these challenges and the future promises these approaches hold.
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Piperlongumine (PL) is an alkaloid that inhibits glutathione S-transferase pi 1 (GSTP1) activity, resulting in elevated reactive oxygen species (ROS) levels and cancer-selective cell death. We aimed to identify stress-associated molecular responses to PL treatment in pancreatic ductal adenocarcinoma (PDAC) cells. GSTP1 directly interacts with JNK, which is activated by oxidative stress and can lead to decreased cancer cell proliferation and cell death. Therefore, we hypothesized that JNK pathways are activated in response to PL treatment. Our results show PL causes dissociation of GSTP1 from JNK; robust JNK, c-Jun, and early ERK activation followed by suppression; increased expression of cleaved caspase-3 and cleaved PARP; and nuclear translocation of Nrf2 and c-Myc in PDAC cells. Gene expression analysis revealed PL caused a > 20-fold induction of heme oxygenase-1 (HO-1), which we hypothesized was a survival mechanism for PDAC cells under enhanced oxidative stress. HO-1 knockout resulted in enhanced PL-induced PDAC cell death under hypoxic conditions. Similarly, high concentrations of the HO-1 inhibitor, ZnPP (10 µM), sensitized PDAC cells to PL; however, lower concentrations ZnPP (10 nM) and high or low concentrations of SnPP both protected PDAC cells from PL-induced cell death. Interestingly, the JNK inhibitor significantly blocked PL-induced PDAC cell death, Nrf-2 nuclear translocation, and HMOX-1 mRNA expression. Collectively, the results demonstrate JNK signaling contributes to PL-induced PDAC cell death, and at the same time, activates Nrf-2 transcription of HMOX-1 as a compensatory survival mechanism. These results suggest that elevating oxidative stress (using PL) while at the same time impairing antioxidant capacity (inhibiting HO-1) may be an effective therapeutic approach for PDAC.
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Apoptose/efeitos dos fármacos , Dioxolanos/farmacologia , Heme Oxigenase-1/genética , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Neoplasias Pancreáticas , Alcaloides/farmacologia , Alcaloides/toxicidade , Linhagem Celular Tumoral/metabolismo , Dioxolanos/toxicidade , Heme Oxigenase-1/metabolismo , Humanos , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Fator 2 Relacionado a NF-E2/efeitos dos fármacos , Fator 2 Relacionado a NF-E2/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/patologia , Espécies Reativas de Oxigênio/metabolismo , Ativação Transcricional/efeitos dos fármacos , Transcriptoma/efeitos dos fármacos , Neoplasias PancreáticasRESUMO
Limited effectiveness of Raf and MEK inhibitors has impelled the interest to use the inhibitors of Extra-cellular Receptor Kinase (ERK) pathway in combination with Gemcitabine (GEM) in pancreatic cancer. However, off-target abundance of ERK receptors, challenging physico-chemical properties, and dose-limiting toxicity of the inhibitor has presented critical challenges towards fabricating this combination amenable for clinical translation. Herein we report a pharmaceutical nanoformulation of GEM and an ERK inhibitor (SCH 772984) co-stabilized within a pH-sensing nanocarrier (NC, with a hydrodynamic diameter of 161 ± 5.0 nm). The NCs were modularly derived from a triblock, self-assembling copolymer, and were chemically conjugated with GEM and encapsulated with SCH772984 at a loading content of 20.2% and 18.3%, respectively. Through pH-mediated unfolding of the individual blocks of the copolymer, the NCs were able to control the release of encapsulated drugs, traffic through cellular membranes, engage target receptors, suppress proliferation of pancreatic cancer cells, and accumulate at disease sites. Collectively our studies showed the feasibility of co-delivery of a combination chemotherapy consisting of GEM and an ERK inhibitor from a NC platform, which can sense and respond to tumor microenvironment of pancreatic cancer setting.
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With the recent rise of alternative instructional methodologies such as flipped classrooms and active learning, many core concepts are being introduced outside of the classroom prior to scheduled class meeting times. One popular means for external concept introduction in many undergraduate biology courses is the use of stand-alone online learning modules. Using a group of four large introductory biology course sections, we investigate the use of a stand-alone online learning module developed using animations from Virtual Cell Animation Collection as a resource for the introduction of cellular respiration concepts outside of the classroom. Results from four sections of introductory biology (n = 629) randomized to treatments show that students who interacted with the stand-alone online learning module had significantly higher normalized gain scores on a cellular respiration assessment than students who only attended a traditional lecture as a means of concept introduction (p < 0.001, d = 0.59). These findings suggest a superior ability to convey certain introductory cellular respiration topics in a stand-alone manner outside of the classroom than in a more traditional lecture-based classroom setting.
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Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers due to a late diagnosis and poor response to available treatments. There is a need to identify complementary treatment strategies that will enhance the efficacy and reduce the toxicity of currently used therapeutic approaches. We investigated the ability of a known ROS inducer, piperlongumine (PL), to complement the modest anti-cancer effects of the approved chemotherapeutic agent gemcitabine (GEM) in PDAC cells in vitro and in vivo. PDAC cells treated with PL + GEM showed reduced cell viability, clonogenic survival, and growth on Matrigel compared to control and individually-treated cells. Nude mice bearing orthotopically implanted MIA PaCa-2 cells treated with both PL (5 mg/kg) and GEM (25 mg/kg) had significantly lower tumor weight and volume compared to control and single agent-treated mice. RNA sequencing (RNA-Seq) revealed that PL + GEM resulted in significant changes in p53-responsive genes that play a role in cell death, cell cycle, oxidative stress, and DNA repair pathways. Cell culture assays confirmed PL + GEM results in elevated ROS levels, arrests the cell cycle in the G0/G1 phase, and induces PDAC cell death. We propose a mechanism for the complementary anti-tumor effects of PL and GEM in PDAC cells through elevation of ROS and transcription of cell cycle arrest and cell death-associated genes. Collectively, our results suggest that PL has potential to be combined with GEM to more effectively treat PDAC.
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Flaxseed consumption is associated with reduced oxidative stress and inflammation in lung injury models and has shown anticancer effects for breast and prostate tissues. However, the chemopreventive potential of flaxseed remains unexplored for lung cancer. In this study, we investigated the effect of flaxseed on tobacco smoke carcinogen (NNK)-induced lung tumorigenesis in an A/J mouse model. Mice exposed to NNK were fed a control diet or a 10% flaxseed-supplemented diet for 26 weeks. Flaxseed-fed mice showed reduced lung tumor incidence (78%) and multiplicity, with an average of 2.7 ± 2.3 surface lung tumor nodules and 1.0 ± 0.9 H&E cross-section nodules per lung compared with the control group, which had 100% tumor incidence and an average of 10.2 ± 5.7 surface lung tumor nodules and 3.9 ± 2.6 H&E cross-section nodules per lung. Furthermore, flaxseed-fed mice had a lower incidence of adenocarcinomas compared with control-fed mice. Western blotting performed on normal lung tissues showed flaxseed suppressed phosphorylation (activation) of p-AKT, p-ERK, and p-JNK kinases. RNA-Seq data obtained from normal lung and lung tumors of control and flaxseed-fed mice suggested that flaxseed intake resulted in differential expression of genes involved in inflammation-mediated cytokine signaling (IL1, 6, 8, 9, and 12α), xenobiotic metabolism (several CYPs, GSTs, and UGTs), and signaling pathways (AKT and MAPK) involved in tumor cell proliferation. Together, our results indicate that dietary flaxseed supplementation may be an effective chemoprevention strategy for chemically induced lung carcinogenesis by altering signaling pathways, inflammation, and oxidative stress. Cancer Prev Res; 11(1); 27-37. ©2017 AACR.
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Carcinogênese/efeitos dos fármacos , Carcinógenos/toxicidade , Citocinas/metabolismo , Linho/química , Mediadores da Inflamação/metabolismo , Neoplasias Pulmonares/prevenção & controle , Extratos Vegetais/farmacologia , Animais , Anticarcinógenos/farmacologia , Benzo(a)pireno/toxicidade , Carcinogênese/metabolismo , Carcinogênese/patologia , Citocromo P-450 CYP1A1/metabolismo , Citocinas/genética , Glucuronosiltransferase/metabolismo , Glutationa Transferase/metabolismo , Sequenciamento de Nucleotídeos em Larga Escala , Pulmão/efeitos dos fármacos , Pulmão/metabolismo , Pulmão/patologia , Neoplasias Pulmonares/induzido quimicamente , Neoplasias Pulmonares/metabolismo , Masculino , Desintoxicação Metabólica Fase II , Camundongos , Camundongos Endogâmicos A , Nitrosaminas/toxicidade , Sementes/químicaRESUMO
Many undergraduate biology courses have begun to implement instructional strategies aimed at increasing student interaction with course material outside of the classroom. Two examples of such practices are introducing students to concepts as preparation prior to instruction, and as conceptual reinforcement after the instructional period. Using a three-group design, we investigate the impact of an animation developed as part of the Virtual Cell Animation Collection on the topic of concentration gradients and their role in the actions of ATP synthase as a means of pre-class preparation or post-class reinforcement compared with a no-intervention control group. Results from seven sections of introductory biology (n = 732) randomized to treatments over two semesters show that students who viewed animation as preparation (d = 0.44, p < 0.001) or as reinforcement (d = 0.53, p < 0.001) both outperformed students in the control group on a follow-up assessment. Direct comparison of the preparation and reinforcement treatments shows no significant difference in student outcomes between the two treatment groups (p = 0.87). Results suggest that while student interaction with animations on the topic of concentration gradients outside of the classroom may lead to greater learning outcomes than the control group, in the traditional lecture-based course the timing of such interactions may not be as important.
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Flaxseed is a rich source of the plant lignan secoisolariciresinol diglucoside (SDG), which is metabolized into mammalian lignans enterodiol (ED) and enterolactone (EL) in the digestive tract. The anticancer properties of these lignans have been demonstrated for various cancer types, but have not been studied for lung cancer. In this study, we investigated the anticancer effects of EL for several nonsmall cell lung cancer (NSCLC) cell lines of various genetic backgrounds. EL inhibited the growth of A549, H441, and H520 lung cancer cells in concentration- and time-dependent manners. The antiproliferative effects of EL for lung cancer cells were not due to enhanced cell death, but rather due to G1-phase cell cycle arrest. Molecular studies revealed that EL decreased mRNA or protein expression levels of the G1-phase promoters cyclin D1, cyclin E, cyclin-dependent kinases (CDK)-2, -4, and -6, and p-cdc25A; decreased phosphorylated retinoblastoma (p-pRb) protein levels; and simultaneously increased levels of p21WAF1/CIP1, a negative regulator of the G1 phase. The results suggest that EL inhibits the growth of NSCLC cell lines by downregulating G1-phase cyclins and CDKs, and upregulating p21WAF1/CIP1, which leads to G1-phase cell cycle arrest. Therefore, EL may hold promise as an adjuvant treatment for lung cancer therapy.
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4-Butirolactona/análogos & derivados , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Quinases Ciclina-Dependentes/metabolismo , Ciclinas/metabolismo , Lignanas/farmacologia , Neoplasias Pulmonares/tratamento farmacológico , 4-Butirolactona/administração & dosagem , 4-Butirolactona/farmacologia , Antineoplásicos Fitogênicos/administração & dosagem , Antineoplásicos Fitogênicos/farmacocinética , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Quinases Ciclina-Dependentes/genética , Ciclinas/genética , Relação Dose-Resposta a Droga , Regulação para Baixo/efeitos dos fármacos , Pontos de Checagem da Fase G1 do Ciclo Celular/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Lignanas/administração & dosagem , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologiaRESUMO
Recent reports calling for change in undergraduate biology education have resulted in the redesign of many introductory biology courses. Reports on one common change to course structure, the active-learning environment, have placed an emphasis on student preparation, noting that the positive outcomes of active learning in the classroom depend greatly on how well the student prepares before class. As a possible preparatory resource, we test the efficacy of a learning module developed for the Virtual Cell Animation Collection. This module presents the concepts of meiosis in an interactive, dynamic environment that has previously been shown to facilitate learning in introductory biology students. Participants (n = 534) were enrolled in an introductory biology course and were presented the concepts of meiosis in one of two treatments: the interactive-learning module or a traditional lecture session. Analysis of student achievement shows that students who viewed the learning module as their only means of conceptual presentation scored significantly higher (d = 0.40, p < 0.001) than students who only attended a traditional lecture on the topic. Our results show the animation-based learning module effectively conveyed meiosis conceptual understanding, which suggests that it may facilitate student learning outside the classroom. Moreover, these results have implications for instructors seeking to expand their arsenal of tools for "flipping" undergraduate biology courses.
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Gráficos por Computador , Instrução por Computador/métodos , Aprendizagem , Meiose , Biologia Molecular/educação , Aprendizagem Baseada em Problemas , Recursos Audiovisuais , Biologia/educação , HumanosRESUMO
BACKGROUND: Systemic toxicity of chemotherapeutic agents and the challenges associated with targeting metastatic tumors are limiting factors for current lung cancer therapeutic approaches. To address these issues, plant-derived bioactive components have been investigated for their anti-cancer properties because many of these agents are non-toxic to healthy tissues. Enterolactone (EL) is a flaxseed-derived mammalian lignan that has demonstrated anti-migratory properties for various cancers, but EL has not been investigated in the context of lung cancer, and its anticancer mechanisms are ill-defined. We hypothesized that EL could inhibit lung cancer cell motility by affecting the FAK-Src signaling pathway. METHODS: Non-toxic concentrations of EL were identified for A549 and H460 human lung cancer cells by conducting 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-Dephenyltetrazolium Bromide (MTT) assays. The anti-migratory and anti-invasive potential of EL for lung cancer cell lines was determined by scratch wound healing and Matrigel® invasion assays. Changes in filamentous actin (F-actin) fiber density and length in EL-treated cells were determined using phalloidin-conjugated rhodamine dye and fluorescent microscopy. Vinculin expression in focal adhesions upon EL treatment was determined by immunocytochemistry. Gene and protein expression levels of FAK-Src signaling molecules in EL-treated lung cancer cells were determined using PCR arrays, qRT-PCR, and western blotting. RESULTS: Non-toxic concentrations of EL inhibited lung cancer cell migration and invasion in a concentration- and time-dependent manner. EL treatment reduced the density and number of F-actin fibers in lung cancer cell lines, and reduced the number and size of focal adhesions. EL decreased phosphorylation of FAK and its downstream targets, Src, paxillin, and decreased mRNA expression of cell motility-related genes, RhoA, Rac1, and Cdc42 in lung cancer cells. CONCLUSIONS: Our data suggest that EL suppresses lung cancer cell motility and invasion by altering FAK activity and subsequent activation of downstream proteins needed for focal adhesion formation and cytoskeletal rearrangement. Therefore, administration of EL may serve as a safe and complementary approach for inhibiting lung tumor cell motility, invasion, and metastasis.
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4-Butirolactona/análogos & derivados , Movimento Celular/efeitos dos fármacos , Linho/química , Lignanas/farmacologia , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/fisiopatologia , Extratos Vegetais/farmacologia , Transdução de Sinais/efeitos dos fármacos , 4-Butirolactona/farmacologia , Adesão Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Citoesqueleto/metabolismo , Quinase 1 de Adesão Focal/genética , Quinase 1 de Adesão Focal/metabolismo , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/genética , Fosforilação/efeitos dos fármacos , Quinases da Família src/genética , Quinases da Família src/metabolismoRESUMO
The use of external representations (ERs) to introduce concepts in undergraduate biology has become increasingly common. Two of the most prevalent are static images and dynamic animations. While previous studies comparing static images and dynamic animations have resulted in somewhat conflicting findings in regards to learning outcomes, the benefits of each have been shown individually. Using ERs developed by the Virtual Cell Animation project, we aim to further investigate student learning using different ERs as part of an introductory biology lecture. We focus our study on the topic of photosynthesis as reports have noted that students struggle with a number of basic photosynthesis concepts. Students (n = 167) in ten sections of introductory biology laboratory were introduced to photosynthesis concepts by instructional lectures differing only in the format of the embedded ERs. Normalized gain scores were calculated, showing that students who learned with dynamic animations outperformed students who learned from static images on the posttest. The results of this study provide possible instructional guidelines for those delivering photosynthesis instruction in the introductory biology classroom. © 2016 by The International Union of Biochemistry and Molecular Biology, 45(3):226-234, 2017.
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Recursos Audiovisuais , Fenômenos Fisiológicos Celulares , Gráficos por Computador , Instrução por Computador/métodos , Biologia Molecular/educação , Fotossíntese/fisiologia , Feminino , Humanos , Masculino , EstudantesRESUMO
Piperlongumine (PL), an alkaloid obtained from long peppers, displays antitumorigenic properties for a variety of human cell- and animal-based models. The aim of this study was to identify the underlying molecular mechanisms for PL anticancer effects on human pancreatic cancer cells. RNA sequencing (RNA-seq) was used to identify the effects of PL on the transcriptome of MIA PaCa-2 human pancreatic cancer cells. PL treatment of pancreatic cancer cells resulted in differential expression of 683 mRNA transcripts with known protein functions, 351 of which were upregulated and 332 of which were downregulated compared to control-treated cells. Transcripts associated with oxidative stress, endoplasmic reticulum (ER) stress, and unfolded protein response pathways were significantly overexpressed with PL treatment. Reverse transcription-quantitative polymerase chain reaction and western blotting were used to validate the RNA-seq results, which included upregulation of HO-1, IRE1α, cytochrome c, and ASNS. The results provide key insight into the mechanisms by which PL alters cancer cell physiology and identify that activation of oxidative stress and ER stress pathways is a critical avenue for PL anticancer effects.
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Dioxolanos/farmacologia , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Neoplasias Pancreáticas/genética , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Perfilação da Expressão Gênica , Humanos , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/fisiopatologiaRESUMO
Consumption of a high-fat diet causes an increase in bile acid deoxycholic acid (DCA) in colon lumen and colon cancer risk, while butyrate, an intestinal microbiota metabolite of dietary fiber, has been shown to exhibit colon cancer-preventive effects. To distinguish these opposing effects of DCA and butyrate (two major metabolites in colon lumen), we examined the effects of physiologically relevant doses of butyrate (0.5-2 mmol/l) and DCA (0.05-0.3 mmol/l) on colon cell proliferation. We hypothesize that butyrate and DCA each modulates the cell cycle and apoptosis via common and distinct cellular signaling targets. In this study, we demonstrated that both butyrate and DCA inhibited cell proliferation by up to 89% and 92% and increased cell apoptosis rate by up to 3.1- and 4.5-fold, respectively. Cell cycle analyses revealed that butyrate led to an increase in G1 and G2 fractions with a concomitant drop in the S-phase fraction, but DCA induced an increase in only G1 fraction with a concomitant drop in the S-phase fraction when compared with the untreated cells. The examination of early cellular signaling revealed that DCA but not butyrate increased intracellular reactive oxygen species, genomic DNA breakage, the activation of ERK1/2, caspase-3 and PARP. In contrast, DCA decreased activated Rb protein level, and butyrate but not DCA increased p21 expression. Collectively, although both butyrate and DCA inhibit colonic cell proliferation, butyrate increases tumor suppressor gene expression, whereas DCA decreases tumor suppressor activation in cell cycle and apoptosis pathways.
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Butiratos/administração & dosagem , Proliferação de Células/efeitos dos fármacos , Neoplasias do Colo/patologia , Ácido Desoxicólico/administração & dosagem , Apoptose , Ciclo Celular/efeitos dos fármacos , Genes Supressores de Tumor/efeitos dos fármacos , Células HCT116 , Humanos , Transdução de SinaisRESUMO
A cell is a minifactory in which structures and molecules are assembled, rearranged, disassembled, packaged, sorted, and transported. Because cellular structures and molecules are invisible to the human eye, students often have difficulty conceptualizing the dynamic nature of cells that function at multiple scales across time and space. To represent these dynamic cellular processes, the Virtual Cell Productions team at North Dakota State University develops freely available multimedia materials to support molecular and cellular biology learning inside and outside the high school and university classroom.
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Biologia Celular/educação , Modelos Educacionais , Biologia Molecular/educaçãoRESUMO
Pancreatic cancer is one of the most deadly cancers with a nearly 95% mortality rate. The poor response of pancreatic cancer to currently available therapies and the extremely low survival rate of pancreatic cancer patients point to a critical need for alternative therapeutic strategies. The use of reactive oxygen species (ROS)-inducing agents has emerged as an innovative and effective strategy to treat various cancers. In this study, we investigated the potential of a known ROS inducer, piperlongumine (PPLGM), a bioactive agent found in long peppers, to induce pancreatic cancer cell death in cell culture and animal models. We found that PPLGM inhibited the growth of pancreatic cancer cell cultures by elevating ROS levels and causing DNA damage. PPLGM-induced DNA damage and pancreatic cancer cell death was reversed by treating the cells with an exogenous antioxidant. Similar to the in vitro studies, PPLGM caused a reduction in tumor growth in a xenograft mouse model of human pancreatic cancer. Tumors from the PPLGM-treated animals showed decreased Ki-67 and increased 8-OHdG expression, suggesting PPLGM inhibited tumor cell proliferation and enhanced oxidative stress. Taken together, our results show that PPLGM is an effective inhibitor for in vitro and in vivo growth of pancreatic cancer cells, and that it works through a ROS-mediated DNA damage pathway. These findings suggest that PPLGM has the potential to be used for treatment of pancreatic cancer.