Distinctive pharmacological differences between liver cancer cell lines HepG2 and Hep3B

24Chronic ER stress occurs when protein misfolding in the ER lumen remains unresolved despite 25 activation of the unfolded protein response. We have shown that traumatic injury such as a 26 severe burn leads to chronic ER stress in vivo leading to systemic inflammation which can last 27 for more than a year. The mechanisms linking chronic ER stress to systemic inflammatory 28 responses is not clear. Here we show that induction of chronic ER stress leads to the release of 29 known and novel damage-associated molecular patterns (DAMPs). The secreted DAMPs are 30 aggregated and markedly protease resistant. ER stress-derived DAMPs activate dendritic cells 31 which are then capable of polarizing naïve T cells. Our findings indicate that induction of 32 chronic ER stress may lead to the release of hyperstable DAMPs into the circulation resulting in 33 persistent systemic inflammation and adverse outcomes. 34 35 Introduction 36The endoplasmic reticulum (ER) is the site of secretory and membrane-bound protein 37 synthesis. Under conditions where ER protein synthesis rates exceed the folding capacity of the 38 ER, unfolded or misfolded proteins accumulate in the ER lumen or membrane. The presence of 39 an excess of misfolded proteins in the ER results in the activation of ER stress signaling 40 pathways to restore homeostasis [1]. For example, ER chaperone content is increased while 41 global protein synthesis rates are decreased in an effort to resolve the folding stress. If ER 42 luminal protein folding stress cannot be resolved, pro-apoptotic pathways are activated resulting 43 in cell death [2, 3]. Chronic ER stress is characterized by activation of this pathway without 44 significant cell death resulting in cellular and organ dysfunction over extended time periods [4]. 45Inflammatory stimuli can lead to chronic ER stress in multiple cells and tissues [5]. For example, 46 activation of the acute phase response results in dramatic upregulation in the synthesis of 47 secretory proteins such as C-reactive protein resulting in hepatic ER stress [6, 7]. We previously 48 found that chronic ER stress is prominent post-burn injury and persists for an extended period 49 after the initial insult [8][9][10][11][12][13][14][15][16][17]. How chronic ER stress mechanistically contributes to post-burn 50 inflammation and metabolic dysfunction is still unclear. 51 NLR Family Pyrin Domain Containing 3 (NLRP3) plays a central role in regulating 52 inflammatory signaling transmitted by damage-associated molecular pattern molecules (DAMPs) 53 derived from stressed or damaged cells [18, 19]. Inflammatory DAMPs include intracellular 54 proteins such as high mobility group box 1 (HMBG1) and non-protein DAMPs such as nucleic 55 acids, both of which are released from dying/damaged cells. Inflammasome activation by 56DAMPs leads to caspase 1 activation, resulting in maturation and secretion of IL-1β and 57 downstream inflammatory responses [20, 21]. DAMP molecules are known to significantly 58 contribute to systemic inflammation and adverse o...

Section: Resultsmentioning

confidence: 99%

Aggregated and hyperstable damage-associated molecular patterns are released during ER stress to modulate immune function

Andersohn

Garcia

Fan

et al. 2019

Preprint

“…All the seven compounds elicited a concentration‐dependent cytotoxic activity against both HepG2 and Hep3b cell lines without marked difference between the two cell lines. The fact that no significant difference was observed in the cytotoxic effect against HepG2 and Hep3b despite the distinct pharmacological properties of the two cell lines , suggested a cell line‐independent mechanism of action of the compounds. Indeed, it is accepted that the cytotoxicity of ent ‐kaurane diterpenoids results from the formation of reactive oxygen species (ROS) through Michael reaction with regulatory thiol‐containing enzymes or coenzymes , likely to be shared by the two HepG2 and Hep3b cell lines and others.…”

Section: Discussionmentioning

confidence: 96%

Cytotoxic, apoptotic, and sensitization properties of ent‐kaurane‐type diterpenoids from Croton tonkinensis Gagnep on human liver cancer HepG2 and Hep3b cell lines

Iscache

Fundamemntal Clinical Pharma

et al. 2016

Human hepatocellular carcinoma (HCC) is the most common type of liver cancer, the second most common cause of death from cancer worldwide. A very poor prognosis and a lack of effective treatments make liver cancer a major public health problem, notably in less developed regions, particularly in eastern Asia. This fully justifies the search of new molecules and therapeutic strategies against HCC. Ent-kaurane diterpenoids are natural compounds displaying a broad spectrum of potential therapeutic effects including anticancer activity. In this study, we analyzed the pharmacological properties of a family of ent-kaurane diterpenoids from Croton tonkinensis Gagnep in human HepG2 and Hep3b cell lines, used as cellular reference models for in vitro evaluation of new molecules active on HCC. A structure-related cytotoxicity was observed against both HCC cell lines, enlighting the role of the 16-en-15-one skeleton of ent-kaurane diterpenoids. Cytotoxicity was closely correlated to apoptosis, evidenced by concentration-dependent subG1 cell accumulation, and increased annexin V expression. In addition, subtoxic concentration of ent-kaurane diterpenoid dramatically enhanced the sensitivity of HCC cells to doxorubicin. All together, our data bring strong support to the potential interest of ent-kaurane diterpenoids, alone or in combination with a cytotoxic agent, in cancer and more precisely against HCC.

“…To explore the biochemical and pharmacological properties of solasonine, we used the well‐characterized human HepG2 and Hep3b cell lines described to represent cellular reference models for in vitro pharmacological studies and proven well adapted for the study of new molecules active on HCC . In addition, of the numerous cell lines used to study hepatocellular carcinoma, both the HepG2 and Hpe3b cell lines are among those which correlate the best to hepatocellular carcinoma tumors, HepG2 being the one displaying the highest correlation .…”

Section: Discussionmentioning

confidence: 99%

In silico analysis of the binding properties of solasonine to mortalin and p53, and in vitro pharmacological studies of its apoptotic and cytotoxic effects on human HepG2 and Hep3b hepatocellular carcinoma cells

Tran

Fundamemntal Clinical Pharma

et al. 2019

Liver cancer, of which human hepatocellular carcinoma (HCC) is the most common type, represents the second most common cause of death from cancer worldwide. To date, treatments remain mostly ineffective and efforts are made to discover new molecules or therapeutic strategies against HCC. Mortalin, an hsp70 chaperone protein, is overexpressed in various cancer, including HCC. Mortalin sequesters p53 into the cytoplasm, thereby inhibiting its translocation to the nucleus and consequently, its cellular functions. Inhibition of mortalin–p53 interactions, which should activate the apoptotic process and the subsequent cell death, has thus been proposed as an anticancer strategy. In silico screening of a database of 354 natural compounds identified solasonine, a steroidal glycoalkaloid from Solanaceae, as a potent inhibitor of p53–mortalin interactions. Pharmacological studies confirmed that solasonine was able to inhibit efficiently mortalin–p53 interaction in HCC HepG2 cell line that expresses both mortalin and p53. This resulted in p53 translocation to the nucleus. Solasonine‐induced apoptosis and cell death of HCC cell lines either expressing p53 (HepG2) or not (Hep3b), indicating that apoptotic activities of solasonine can be mediated not only through p53‐dependent but also p53‐independent pathways. The cytotoxic effects of solasonine correlated in part with its apoptotic properties and differed in the two HCC cell lines, being reversed by pifithrin‐α, an inhibitor of p53 functions, in HepG2 cells but not in Hep3b cells. Nonapoptotic cell death was also observed, notably in Hep3b cells.