Despite the undeniable progress made in the last decades, cancer continues to challenge the scientists engaged in searching for an effective treatment for its prevention and cure. One of the malignant hallmarks that characterize cancer cell biology is the altered metabolism of sugars and amino acids. Autophagy is a pathway allowing the macromolecular turnover via recycling of the substrates resulting from the lysosomal degradation of damaged or redundant cell molecules and organelles. As such, autophagy guarantees the proteome quality control and cell homeostasis. Data from in vitro, in animals and in patients researches show that dysregulation of autophagy favors carcinogenesis and cancer progression, making this process an ineluctable target of cancer therapy. The autophagy process is regulated at genetic, epigenetic and post-translational levels. Targeting autophagy with epigenetic modifiers could represent a valuable strategy to prevent or treat cancer. A wealth of natural products from terrestrial and marine living organisms possess anti-cancer activity. Here, we review the experimental proofs demonstrating the ability of natural compounds to regulate autophagy in cancer via epigenetics. The hope is that in the near future this knowledge could translate into effective intervention to prevent and cure cancer.
In the event of amino acid starvation, the cell activates two main protective pathways: Amino Acid starvation Response (AAR), to inhibit global translation, and autophagy, to recover the essential substrates from degradation of redundant self-components. Whether and how AAR and autophagy (ATG) are cross-regulated and at which point the two regulatory pathways intersect remain unknown. Here, we provide experimental evidence that the mammalian target of rapamycin (mTOR) complex 1 (mTORC1) specifically located at the lysosome level links the AAR with the autophagy pathway.
Macroautophagy is a catabolic process through which redundant, aged, or damaged cellular structures are first enclosed within double-membrane vesicles (called autophagosomes), and thereafter degraded within lysosomes. Macroautophagy provides a primary route for the turnover of macromolecules, membranes and organelles, and as such plays a major role in cell homeostasis. As part of the stress response, autophagy is crucial to determine the cell fate in response to extracellular or intracellular injuries. Autophagy is involved in cancerogenesis and in cancer progression. Here we illustrate the essential methods for monitoring autophagy in pancreatic cancer cells.
Cancer-associated fibroblasts (CAFs) play a critical role in cancer progression, metastasis, and therapy resistance. Molecular events that confer CAF-phenotype to predecessor-cells are not fully understood. We demonstrate here that the ovarian cancer cell-conditioned medium (OCC-CM) induces CAF-phenotype in MRC5 lung-fibroblasts and it can be mimicked by LPA. While OCC-CM and LPA stimulated the expression of cellular CAF-markers by 3-days, they induced aerobic glycolysis, a metabolic marker for CAF, by 6 hrs. OCC-CM/LPA-induced glycolysis in lung (MRC5) as well as ovarian fibroblasts (NOF151) was inhibited by the LPA-receptor antagonist, Ki16425. Ovarian cancer patient-derived ascitic fluid-induced aerobic glycolysis in both NFs and Ovarian CAFs and it was inhibited by Ki16425. Further analysis indicated that LPA upregulated HIF1α-levels and the silencing of HIF1α attenuated LPA-induced glycolysis in both NOFs and CAFs. These results establish LPA-induced glycolytic-shift as the earliest, potentially priming event, in NF to CAF-transition. These findings also identify a role for LPA-LPAR-HIF1α signaling-hub in the maintenance of the glycolytic-phenotype in CAFs. Our results provide evidence that targeted inhibition of LPA-mediated metabolic reprogramming in CAFs may represent an adjuvant therapy in ovarian cancer.
Cholangiocarcinoma (CCA) is a very aggressive cancer arising from the malignant transformation of cholangiocytes. Intrahepatic CCA is associated with reactive inflammation and intense fibrosis of the hepatobiliary tract. Dihydroartemisinin (DHA), the active compound found in Artemisia annua, has been shown to possess anti-tumor activity in a variety of human cancers, including hepatoma. Here, we tested the ability of DHA to specifically kill CCA cells and have investigated the underlying mechanisms. DHA induced both apoptosis and autophagy-dependent caspase-independent cell death in many CCA cell lines, while being slightly toxic to immortalized cholangiocytes. DHA induced the expression of many apoptosis- and autophagy-related genes in CCA cells. In particular, it greatly induced the expression of DAPK1, and reduced the interaction of BECLIN1 with BCL-2 while promoting its interaction with PI3KC3. Genetic silencing of DAPK1 prevented DHA-induced autophagy. Pharmacologic and genetic inhibition of BECLIN1 function prevented autophagy and cell death induced by DHA in CCA cells. These data unravel a novel pathway of DHA cancer toxicity and open the possibility to introduce DHA in the therapeutic regimen for the treatment of CCA. This article is protected by copyright. All rights reserved.
Invertebrate neuropeptide F-I (NPF-I), much alike its mammalian homolog neuropeptide Y, influences several physiological processes, including circadian rhythms, cortical excitability, stress response, and food intake behavior. Given the role of autophagy in the metabolic stress response, we investigated the effect of NPF-1 on autophagy during fasting and feeding conditions in the hepatopancreas and muscle tissues of the male giant freshwater prawn . Starvation up-regulated the expression of the autophagy marker LC3 in both tissues. Yet, based on the relative levels of the autophagosome-associated LC3-II isoform and of its precursor LC3-I, the hepatopancreas was more responsive than the muscle to starvation-induced autophagy. Injection of NPF-I inhibited the autophagosome formation in the hepatopancreas of fasting prawns. Relative to the body weight, the muscle weight was not affected, while that of the hepatopancreas decreased upon starvation and NPF-1 treatment could largely prevent such weight loss. Thus, the hepatopancreas is the reserve organ for the nutrient homeostasis during starvation and NPF-I plays a crucial role in the balancing of energy expenditure and energy intake during starvation by modulating autophagy.
Cholangiocarcinoma (CCA), the cancer arising from the epithelial cells of bile ducts, is a prototype of inflammatory-driven cancer. Cytokines released by cancer associated fibroblasts (CAFs) play a pivotal role in CCA progression, driving the epigenetic Epithelial-to-Mesenchymal transition and the growth and metastasization of CCA cells. Consistently, the conditioned medium from CCA-derived CAFs further stimulated the secretion of IL-6, and to a lesser extent of IL-8, by CCA cells. CCA has a poor prognosis, because of late diagnosis and of high resistance to radio- and chemo-therapy of CCA cells. Targeting the CAFs and their secretion could be an alternative option. We found that while IL-6 indeed promoted the cell migration of invasive CCA cells, the nutraceutical Resveratrol strongly counteracted this effect both in CCA cells and in immortalized cholangiocytes. More importantly, here we show that Resveratrol has the potential to abrogate the secretion of IL-6 by CAFs. While the conditioned medium from CAFs strongly induced IL-6 mediated motility of CCA cells, the conditioned medium from CAFs pre-treated with Resveratrol completely halted cancer cell motility and reverted the N-to E-cadherin switch in migrating cells. This effect was associated with stimulation of autophagy in the cancer cells. This is the first demonstration that CAFs secretory products directly affect the regulation of autophagy and consequently the behavior of CCA cells, and that a nutraceutical may revert the malignant phenotype of cancer cells by acting on CAFs metabolism and secretion.
Although hypoxia has been shown to reprogram cancer cells toward glycolytic shift, the identity of extrinsic stimuli that induce metabolic reprogramming independent of hypoxia, especially in ovarian cancer, is largely unknown. In this study, we use patient-derived ovarian cancer cells and high-grade serous ovarian cancer cell lines to demonstrate that lysophosphatidic acid (LPA), a lipid growth factor and GPCR ligand whose levels are substantially increased in ovarian cancer patients, triggers glycolytic shift in ovarian cancer cells. Inhibition of the G protein α-subunit Gαi2 disrupted LPA-stimulated aerobic glycolysis. LPA stimulated a pseudohypoxic response via Rac-mediated activation of NADPH oxidase and generation of reactive oxygen species, resulting in activation of HIF1α. HIF1α in turn induced expression of glucose transporter-1 and the glycolytic enzyme hexokinase-2 (HKII). Treatment of mice bearing ovarian cancer xenografts with an HKII inhibitor, 3-bromopyruvate, attenuated tumor growth and conferred a concomitant survival advantage. These studies reveal a critical role for LPA in metabolic reprogramming of ovarian cancer cells and identify this node as a promising therapeutic target in ovarian cancer. These findings establish LPA as a potential therapeutic target in ovarian cancer, revealing its role in the activation of HIF1α-mediated metabolic reprogramming in this disease. .
Cancer and stromal cells, which include (cancer-associated) fibroblasts, adipocytes, and immune cells, constitute a mixed cellular ecosystem that dynamically influences the behavior of each component, creating conditions that ultimately favor the emergence of malignant clones. Ovarian cancer cells release cytokines that recruit and activate stromal fibroblasts and immune cells, so perpetuating a state of inflammation in the stroma that hampers the immune response and facilitates cancer survival and propagation. Further, the stroma vasculature impacts the metabolism of the cells by providing or limiting the availability of oxygen and nutrients. Autophagy, a lysosomal catabolic process with homeostatic and prosurvival functions, influences the behavior of cancer cells, affecting a variety of processes such as the survival in metabolic harsh conditions, the invasive growth, the development of immune and chemo resistance, the maintenance of stem-like properties, and dormancy. Further, autophagy is involved in the secretion and the signaling of promigratory cytokines. Cancer-associated fibroblasts can influence the actual level of autophagy in ovarian cancer cells through the secretion of pro-inflammatory cytokines and the release of autophagy-derived metabolites and substrates. Interrupting the metabolic cross-talk between cancer cells and cancer-associated fibroblasts could be an effective therapeutic strategy to arrest the progression and prevent the relapse of ovarian cancer.
Licha ya maendeleo yasiyoweza kukataliwa yaliyofanywa katika miongo ya hivi karibuni, kansa inaendelea kuwa changamoto kwa wanasayansi wanaofanya kazi ya kutafuta matibabu yenye ufanisi ya kuzuia na kutibu. Mojawapo ya dalili mbaya za chembe za kansa ni mabadiliko katika kimetaboliki ya sukari na asidi za amino. Autophagy ni njia ya kuruhusu macromolecular turnover kupitia recycling ya substrates kutokana na lysosomal uharibifu wa molekuli kuharibiwa au redundant seli na organelles. Kama vile, autophagy inahakikisha udhibiti wa ubora wa proteome na homeostasis ya seli. Takwimu kutoka kwa in vitro, katika wanyama na katika utafiti wa wagonjwa zinaonyesha kwamba dysregulation ya autophagy inasaidia carcinogenesis na maendeleo ya kansa, na kufanya mchakato huu lengo la matibabu ya kansa. Utaratibu wa autophagy umedhibitiwa katika viwango vya maumbile, epigenetic na baada ya tafsiri. Kulenga autophagy na epigenetic modifiers inaweza kuwakilisha mkakati wa thamani ya kuzuia au kutibu kansa. Vitu vingi vya asili kutoka kwa viumbe hai wa nchi kavu na baharini vina utendaji wa kupambana na kansa. Hapa, tunakagua uthibitisho wa majaribio unaoonyesha uwezo wa misombo ya asili kudhibiti autophagy katika kansa kupitia epigenetics. Tumaini ni kwamba katika siku zijazo za karibu ujuzi huu unaweza kutafsiriwa kuwa hatua ya ufanisi ya kuzuia na kutibu kansa. Katika hali ya njaa ya amino asidi, seli huamsha njia mbili kuu za kinga: Amino Acid Starvation Response (AAR), kuzuia tafsiri ya jumla, na autophagy, kurudisha substrates muhimu kutoka kwa uharibifu wa vipengele vya kujitegemea vya ziada. Kama na jinsi AAR na autophagy (ATG) ni msalaba-kuadhibitiwa na katika hatua ambayo njia mbili za udhibiti kukutana kubaki haijulikani. Katika utafiti huu, tulionyesha kwamba mRNA ya rapamycin (mTOR) complex 1 (mTORC1) inaunganisha AAR na njia ya autophagy. Macroautophagy ni mchakato wa catabolic kupitia ambayo redundant, umri, au kuharibiwa muundo wa seli ni kwanza kufungwa ndani ya vesicles double-membrane (aitwa autophagosomes), na baadaye degraded ndani ya lysosomes. Makroautophagy hutoa njia ya msingi kwa ajili ya mzunguko wa macromolecules, utando na organelles, na kama vile ina jukumu kubwa katika homeostasis ya seli. Kama sehemu ya majibu ya mkazo, autophagy ni muhimu kuamua hatima ya seli katika kujibu majeraha ya nje ya seli au ya ndani ya seli. Autophagy inahusika katika cancerogenesis na katika maendeleo ya kansa. Hapa tunaonyesha mbinu muhimu kwa ajili ya ufuatiliaji autophagy katika seli za kansa ya kongosho. Fibroblasts zinazohusiana na kansa (CAFs) zina jukumu muhimu katika maendeleo ya kansa, metastasis, na upinzani wa tiba. Matukio ya molekuli ambayo hutoa CAF-phenotype kwa seli za mtangulizi hayaeleweki kikamilifu. Kwa mfano, kwa mfano, ovarian kansa ya seli-conditioned (OCC-CM) inaweza kuchochea CAF phenotype katika MRC5 mapafu fibroblasts na inaweza kuigwa na LPA. Wakati OCC-CM na LPA zilichochea usemi wa alama za CAF za seli kwa siku 3, zilichochea glycolysis ya aerobic, alama ya kimetaboliki ya CAF, kwa masaa 6. OCC-CMA na LPA-induced glycolysis katika mapafu (MRC5) na ovarian fibroblasts (NOF151) ilizuiliwa na kiwambo cha kiwambo cha kiwambo cha kiwambo cha kiwambo cha kiwambo cha kiwambo cha kiwambo cha kiwambo cha kiwambo cha kiwambo cha kiwambo cha kiwambo cha kiwambo cha kiwambo cha kiwambo. Kiwango cha juu cha ascitic fluid-induced aerobic glycolysis katika ovari ya ovari (NF) na ovari ya ovari (CAF) ni Ki16425 Uchunguzi zaidi ulionyesha kwamba LPA iliimarisha viwango vya HIF1a na kusimamisha HIF1a ilidhibiti glycolysis inayosababishwa na LPA katika NOF na CAF. Matokeo haya kuanzisha LPA-induced glycolytic-mabadiliko kama mapema, uwezekano priming tukio, katika NF kwa CAF-mabadiliko. Matokeo haya pia kutambua jukumu kwa ajili ya LPA-LPAR-HIF1a signaling-hub katika matengenezo ya glycolytic-phenotype katika CAFs. Matokeo yetu hutoa ushahidi kwamba kuzuia lengo la LPA-mediated metabolic reprogramming katika CAFs inaweza kuwakilisha tiba ya adjuvant katika kansa ya ovari. Cholangiocarcinoma (CCA) ni aina ya kansa ya kansa ya kansa ya kansa ya kansa ya kansa ya kansa ya kansa ya kansa ya kansa ya kansa ya kansa ya kansa ya kansa ya kansa ya kansa ya kansa. CCA ya ndani ya ini inahusishwa na uvimbe wa athari na fibrosis kali ya njia ya hepatobiliary. Dihydroartemisinin (DHA) ni kiungo cha kazi katika Artemisia annua, ambayo inaonyesha uwezo wa kupambana na kansa katika aina mbalimbali za kansa za binadamu, ikiwa ni pamoja na hepatoma. Katika utafiti huu, tulijaribu uwezo wa DHA kuua seli za CCA na kuchunguza utaratibu wa msingi. DHA ilisababisha apoptosis na kifo cha seli cha caspase-independent katika mistari mingi ya seli ya CCA, wakati ilikuwa na sumu kidogo kwa cholangiocytes isiyo na kifo. DHA huchochea usemi wa jeni nyingi zinazohusiana na apoptosis na autophagy katika seli za CCA. Kwa mfano, DAPK1 ina athari kubwa kwa BECL1 na BCL2 na ina athari kubwa kwa PI3KC3. Ugonjwa wa DAPK1 ulizuia autophagy inayosababishwa na DHA. Inhibition ya dawa na ya maumbile ya kazi ya BECLIN1 ilizuia autophagy na kifo cha seli kilichochochewa na DHA katika seli za CCA. Takwimu hizi zinafunua njia mpya ya sumu ya saratani ya DHA na kufungua uwezekano wa kuanzisha DHA katika matibabu ya CCA. Makala hii inalindwa na haki za uchapaji. Haki zote zimehifadhiwa. Neuropeptide ya wanyama wasio na uti wa mgongo (NPF-I) - kama vile neuropeptide ya mamalia (YY) - huathiri michakato kadhaa ya kisaikolojia, pamoja na rhythms ya circadian, excitability ya cortical, majibu ya mkazo, na tabia ya ulaji wa chakula. Kwa kuzingatia jukumu la autophagy katika majibu ya metabolic stress, tulichunguza athari ya NPF-1 kwenye autophagy wakati wa kufunga na hali ya kulisha katika hepatopancreas na tishu za misuli ya jike kubwa ya maji safi. Kwa mfano, ukosefu wa chakula kwa muda mrefu huongeza utendaji wa LC3 (au autophagy marker) katika tishu zote mbili. Kwa mujibu wa viwango vya kiasi cha auto-phagocyte-associated LC3I isoform na LC3I, hepatopancreas ilikuwa zaidi ya msikivu kuliko misuli kwa autophagy njaa-induced. Injection ya NPF-I inhibit autophagosome malezi katika hepatopancreas ya shrimp njaa. Kwa mujibu wa uzito wa mwili, uzito wa misuli haukuathiriwa, wakati ule wa hepatopancreas ulipungua wakati wa njaa na matibabu ya NPF-1 inaweza kuzuia kupoteza uzito kama huo. Kwa hivyo, hepatopancreas ni chombo cha kuhifadhi homeostasis ya virutubisho wakati wa njaa, na NPF-I ina jukumu muhimu katika kusawazisha matumizi ya nishati na ulaji wa nishati wakati wa njaa kwa kurekebisha autophagy. Cholangiocarcinoma (CCA) ni kansa ya tumbo la tumbo la tumbo la tumbo la tumbo la tumbo la tumbo la tumbo la tumbo la tumbo la tumbo la tumbo la tumbo la tumbo la tumbo la tumbo la tumbo. Cytokines zinazotolewa na fibroblasts zinazohusiana na kansa (CAFs) hucheza jukumu muhimu katika maendeleo ya CCA, kuendesha mpito wa epigenetic-to-mesenchymal na ukuaji na metastasis ya seli za CCA. Kwa kawaida, chombo cha hali kutoka kwa CAFs inayotokana na CCA ilichochea zaidi sekreti ya IL-6 na kwa kiwango kidogo cha IL-8 na seli za CCA. CCA ina utabiri mbaya, kwa sababu ya utambuzi wa marehemu na upinzani mkubwa kwa redio na chemotherapy ya seli za CCA. Kuangalia CAFs na secretion yao inaweza kuwa chaguo mbadala. "Kama IL-6 iliongeza ""uhamaji wa seli"" wa seli za CCA, Resveratrol ilizuia athari hii katika seli za CCA na katika choloangiosytes." Kwa upande mwingine, Resveratrol inaweza kuathiri ufumbuzi wa IL-6 na CAFs. Wakati mazingira ya hali ya CAFs yaliongoza nguvu IL-6-mediated motility ya seli za CCA, mazingira ya hali ya CAFs yaliyotibiwa mapema na resveratrol yalisimamisha kabisa motility ya seli za saratani na kurudisha N-cadherin kwenye seli za uhamiaji. Athari hii ilihusianishwa na kuchochea autophagy katika chembe za kansa. Hii ni maonyesho ya kwanza kwamba bidhaa za secretory za CAF zinaathiri moja kwa moja udhibiti wa autophagy na kwa hivyo tabia ya seli za CCA, na kwamba nutraceutical inaweza kurudi phenotype mbaya ya seli za kansa kwa kutenda juu ya metabolism na secretion ya CAF. Ingawa hypoxia imeonyeshwa kuhariri seli za kansa kuelekea mabadiliko ya glycolytic, utambulisho wa vichocheo vya nje ambavyo husababisha programu ya kimetaboliki isiyo na uhusiano na hypoxia, haswa katika saratani ya ovari, haijulikani sana. Katika utafiti huu, tumetumia seli za saratani ya ovari zilizopatikana kutoka kwa wagonjwa na mistari ya seli za saratani ya ovari ya kiwango cha juu ili kuonyesha kwamba asidi ya lysophosphatidic (LPA), sababu ya ukuaji wa lipid na ligand ya GPCR, ambayo viwango vyao vimeongezeka kwa kiasi kikubwa kwa wagonjwa wa saratani ya ovari, huchochea mabadiliko ya glycolytic katika seli za saratani ya ovari. Inhibition ya G-protein subunit ya G-protein ya G-protein ya G-protein ya G-protein ya G-protein ya G-protein ya G-protein ya G-protein ya G-protein ya G-protein ya G-protein ya G-protein ya G-protein ya G-protein ya G-protein ya G-protein ya G-protein ya G-protein ya G-protein ya G-protein. LPA huchochea majibu ya pseudohypoxic kupitia uanzishaji wa NADPH oxidase na kizazi cha spishi za oksijeni, na kusababisha uanzishaji wa HIF1a. H1N1 al-glycosylated na hexokinase-II (H1N2) Kwa panya walio na xenograft ya saratani ya ovari, matibabu ya 3-bromopyrivate, inhibitor ya HKII, ilidhibiti ukuaji wa uvimbe na kutoa faida ya kuishi. Utafiti huu unafunua jukumu muhimu kwa LPA katika programu ya kimetaboliki ya seli za saratani ya ovari na kutambua node hii kama lengo la matibabu la kuahidi katika saratani ya ovari. Matokeo haya yanaanzisha LPA kama lengo la matibabu ya uwezekano katika saratani ya ovari, ikifunua jukumu lake katika uanzishaji wa HIF1A-medied metabolic reprogramming katika ugonjwa huu. . Chembe za saratani na stromal, ambazo ni pamoja na fibroblasts, adipocytes, na seli za kinga, zinaunda mfumo mchanganyiko wa seli ambao huathiri tabia ya kila sehemu, na kuunda hali ambazo hatimaye zinafaa kuibuka kwa clones mbaya. Chembe za saratani ya ovari hutokeza cytokines ambazo huchagua na kuamsha stromal fibroblasts na seli za kinga, hivyo kuendeleza hali ya uvimbe katika stroma ambayo huzuia majibu ya kinga na kuwezesha kuishi na kuenea kwa saratani. Zaidi ya hayo, mfumo wa mishipa ya stroma huathiri kimetaboliki ya chembe kwa kutoa au kupunguza upatikanaji wa oksijeni na virutubisho. Autophagy ni mchakato wa lysosomal catabolic na kazi homeostatic na prosurvival, ambayo huathiri tabia ya seli za saratani, kuathiri mchakato mbalimbali kama vile kuishi katika hali ngumu metabolic, ukuaji wa uvamizi, maendeleo ya kinga na chemo upinzani, kudumisha mali ya shina kama, na dormancy. Zaidi ya hayo, autophagy inahusika katika secretion na ishara ya promigratory cytokines. Fibroblasts zinazohusiana na saratani zinaweza kuathiri kiwango halisi cha autophagy katika seli za saratani ya ovari kupitia sekreti ya cytokines ya pro-inflammatory na kutolewa kwa metabolites na substrates zinazotokana na autophagy. Kuingilia kati kwa metabolic kati ya seli za saratani na fibroblasts zinazohusiana na saratani inaweza kuwa mkakati mzuri wa matibabu ili kuzuia maendeleo na kuzuia kurudia kwa saratani ya ovari.