Bid exhibits S phase checkpoint activation and plays a pro-apoptotic role in response to etoposide-induced DNA damage in hepatocellular carcinoma cells

Green extraction of bioactive compounds from wine lees and their bio-responses on immune modulation using in vitro sheep model

The objective of this study was to apply microwave-assisted extraction using green solvents starting from 3 different wine (white, rosé, and red) lees and to test their bio-response on sheep peripheral blood mononuclear cells proliferation, Bax/Bcl-2 ratio, and cytokines secretion. Wine lees (WL) of local organic farming from white wine, produced with Trebbiano cultivar, rosé and red wine, made with Nero di Troia cultivar, were collected. The WL were subjected to microwave-assisted extraction using 2 green solvents (water and ethanol) in 3 different combinations (water; water/ethanol 1:1 vol/vol; ethanol) with a dry matter-to-solvent ratio of 1:40 (wt/vol) at 4 temperature levels: 50, 100, 150, and 200°C. Sodium carbonate Na₂CO₃ (2 mmol/g of dry weight of lees) was used for increasing the polyphenol extraction yield. A total number of 6 extracts, 2 for each kind of WL investigated, according to their total phenolic content and in vitro antioxidant capacity, were selected to be tested on sheep peripheral blood mononuclear cells, as an animal model. All the WL extracts demonstrated a strong antiproliferative action. On the contrary, the cytokines' profile was mainly dependent on the different winemaking derived WL and the extraction solvent combination procedures. Red WL extract obtained by a combination of water/Na₂CO₃ and tested at 0.8 mg/mL, resulted in an increase of both IL-6 secretion and Bax/Bcl-2 ratio. Data from the present study demonstrated that WL extracts derived from different winemaking and solvent extraction could have a bimodal action on control of inflammatory mediated damage and highlighted the importance for further studies aimed at applying the biorefinery process on by-products to increase their economic value and exploit new derived bioactive compound.

Berberine inhibits colitis-associated tumorigenesis via suppressing inflammatory responses and the consequent EGFR signaling-involved tumor cell growth

The anti-inflammatory and anti-tumor effects of berberine, a traditional Chinese medicine, were separately discovered in pathological intestinal tissues. However, whether the anti-inflammatory effect of berberine contributes to its anti-tumor effect on colitis-associated colorectal cancer (CACRC) remains unknown. In the present study, we found that berberine effectively inhibited colitis-associated tumorigenesis and colonic epithelium hyperproliferation in dextran sulfate sodium (DSS)-treated Apc^Min/+ mice. A mechanistic study identified that these inhibitory effects of berberine occurred through blocking interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) expression in colonic macrophages. An in vitro study on cell lines identified that berberine treatment of Raw 264.7 macrophages resulted in conditioned media with fewer proliferative effects on a cell line with a heterozygous Apc mutation (Immorto-Min colonic epithelium, IMCE). EGFR-ERK signaling act downstream of berberine/pro-inflammatory cytokines axis to regulate CACRC cell proliferation. Furthermore, in vivo administration of IL-6 to DSS-treated Apc^Min/+ mice effectively weakened the inhibitory effects of berberine on tumorigenesis and EGFR-ERK signaling in colon tissues. Altogether, the results of our studies have revealed that berberine inhibits the development of CACRC by interfering with inflammatory response-driven EGFR signaling in tumor cell growth. The findings of this study support the possibility that berberine and other anti-inflammatory drugs may be beneficial in the treatment of CACRC.

Identification and safety evaluation of a product from the biodegradation of ochratoxin A by an Aspergillus strain

BACKGROUND

Ochratoxin A (OTA) poses a serious health hazard throughout the world and is often reported in food commodities. At present, biological approaches to detoxifying OTA are now widely considered to be the most promising methods.

RESULTS

In this study, a strain that was identified as Aspergillus niger was isolated, and it has a strong ability to detoxify OTA. The degradation product (compound 1) of OTA was treated with crude enzyme. The product has been isolated and identified as C₁₁ H₉ O₅ Cl (ochratoxin α), which is a weak lipophilic molecule, in contrast to fat-soluble OTA. The cytotoxic response of compound 1 was revealed to be different to that of OTA. Compound 1 does not induce cellular oxidative damage in comparison with OTA, which may cause lipid peroxidation (MDA), reduce SOD activity and induce DNA damage.

CONCLUSION

This study indicates that A. niger has the ability to detoxify OTA. The OTA degradation product, ochratoxin α, does not exert cytotoxic effects on cell metabolism. A. niger has prospective uses for the OTA decontamination of food and agricultural fields. © 2016 Society of Chemical Industry.

Synergy of BID with doxorubicin in the killing of cancer cells

Overexpression of the BH3-interacting domain death agonist (BID) protein sensitizes certain cancer cell lines to apoptosis induced by anticancer agents, particularly by those acting through death receptors (e.g. TRAIL). Previously, we showed that recombinant BID fused with TAT cell penetrating peptide (TAT-BID) allowed for controlled delivery of BID to different cancer cell lines and moderately sensitized some of them to TRAIL or slightly to camptothecin. In the present study, we showed that TAT-BID delivered to HeLa cells strongly sensitized them to doxorubicin, as identified by cell viability and apoptosis assays. Another cell line sensitized to doxorubicin was PC3, whereas A549 and LNCaP cells were sensitized moderately or not at all, respectively. Sensitization was more pronounced at 1 μM doxorubicin administered for 48 h than for lower doses and shorter treatments. TAT-BID and doxorubicin may thus be considered as a potential therapeutic combination for cervical carcinoma and advanced prostate cancer treatment.

Controlled delivery of BID protein fused with TAT peptide sensitizes cancer cells to apoptosis

BACKGROUND

Low cellular level of BID is critical for viability of numerous cancer cells. Sensitization of cells to anticancer agents by BID overexpression from adenovirus or pcDNA vectors is a proposed strategy for cancer therapy; however it does not provide any stringent control of cellular level of BID. The aim of this work was to examine whether a fusion of BID with TAT cell penetrating peptide (TAT-BID) may be used for controlled sensitization of cancer cells to anticancer agents acting through death receptors (TRAIL) or DNA damage (camptothecin). Prostate cancer PC3 and LNCaP, non-small human lung cancer A549, and cervix carcinoma HeLa cells were used in the study.

METHODS

Uptake of TAT-BID protein by cells was studied by quantitative Western blot analysis of cells extracts. Cells viability was monitored by MTT test. Apoptosis was detected by flow cytometry and cytochrome c release assay.

RESULTS

TAT-BID was delivered to all cancer cells in amounts depending on time, dose and the cell line. Recombinant BID sensitized PC3 cells to TRAIL or, to lesser extent, to camptothecin. Out of remaining cells, TAT-BID sensitized A549, and only slightly HeLa cells to TRAIL. None of the latter cell lines were sensitized to camptothecin. In all cases the mutant not phosphorylable by CK2 (TAT-BIDT59AS76A) was similarly efficient in sensitization as the wild type TAT-BID.

CONCLUSIONS

TAT-BID may be delivered to cancer cells in controlled manner and efficiently sensitizes PC3 and A549 cells to TRAIL. Therefore, it may be considered as a potential therapeutic agent that enhances the efficacy of TRAIL for the treatment of prostate and non-small human lung cancer.

Involvement of BID translocation in glycyrrhetinic acid and 11-deoxy glycyrrhetinic acid-induced attenuation of gastric cancer growth

Glycyrrhetinic acid (GA), the main chemical constituents of licorice, has shown remarkable anticancer activity. However, the side effects limit its widespread use. 11-DOGA is produced through reduction of GA 11-carbonyl to 11-hydroxyl to reduce its side effects, although its anticancer activities are largely unknown. Here, we report that the functional mechanisms of GA and 11-DOGA in gastric cancers, as well as the comparison between these two drugs' pharmacological potential. Firstly, we found that GA and 11-DOGA significantly inhibits the viabilities of gastric cancer cells in dose- and time-dependent manners. Both GA and 11-DOGA induce gastric cancer cells apoptosis and cell cycle arrest in G2 phase by upregulation of p21 and downregulation of cdc2 and cyclin B1. Further studies show that GA and 11-DOGA-induced apoptosis in gastric cancer cells is associated with BID translocation from nucleus to mitochondria. Moreover, GA and 11-DOGA could effectively inhibit tumor formation of gastric cancer cells in nude mice. Comparing with 11-DOGA, GA presents higher toxicity toward gastric cancer cells both in vivo and in vitro. Thus, the elucidation of the functional mechanisms of GA and 11-DOGA-induced attenuation of gastric cancer growth suggests a possible therapeutic role of GA and its derivatives.

Bid-overexpression regulates proliferation and phosphorylation of Akt and MAPKs in response to etoposide-induced DNA damage in hepatocellular carcinoma cells

Background

Growing evidence supports BH3-interacting domain death agonist (Bid) playing a dual role in DNA damage response. However, the effects of Bid on hepatocellular carcinoma (HCC) cell proliferation in response to etoposide-induced DNA damage have not been sufficiently investigated.

Methods

Using a stable Bid-overexpression HCC cell line, Bid/PLC/PRF/5, overexpression of Bid promoted loss of viability in response to etoposide-induced DNA damage. MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide]- and BrdU (5′-bromo-2′-deoxyuridine)-labeling assays revealed that etoposide-inhibited HCC cells grew in concentration-and time-dependent manners. The phosphorylations of Akt and mitogen-activated protein kinases (MAPKs) in response to etoposide-induced DNA damage were analyzed by Western blotting.

Results

The survival rates of 100 μM etoposide on the cells with control vector and Bid/PLC/PRF/5 at 48 hours amounted to 71% ± 0.75% and 59% ± 0.60% with MTT assay, and similar results of 85% ± 0.08% and 63% ± 0.14% with BrdU-labeling assay respectively. Moreover, overexpression of Bid sensitized the cells to apoptosis at a high dose of etoposide (causing irreparable damage). However, it had little effect on the proliferation at a low dose of etoposide (repairable damage). Furthermore, the phosphorylation status of Akt and MAPKs were investigated. Overexpression of Bid suppressed the activation of Akt with respect to etoposide-induced DNA damage. Similar to Akt, the levels of phosphorylated p38 and phosphorylated c-Jun were attenuated by Bid-overexpression. On the contrary, the level of phosphorylated ERK1/2 was sustained at a high level, especially in Bid/PLC/PRF/5 cells.

Conclusion

Taken together, these results suggest that overexpression of Bid suppressed the activation of Akt, p38, and c-Jun, and promoted the activation of ERK1/2 induced by etoposide, suggesting that the promotion of ERK1/2 activation may have a negative effect on Bid-mediated HCC DNA damage induced by etoposide.

Intestinal metabolite compound K of panaxoside inhibits the growth of gastric carcinoma by augmenting apoptosis via Bid-mediated mitochondrial pathway

Compound K (20-O-β-D-glucopyranosyl-20(S)-protopanaxadiol, CK), an intestinal bacterial metabolite of panaxoside, has been shown to inhibit tumour growth in a variety of tumours. However, the mechanisms involved are largely unknown. We use human gastric carcinoma cell lines BGC823, SGC7901 and human gastric carcinoma xenograft in nude mice as models to study the mechanisms of CK in gastric cancers. We found that CK significantly inhibits the viabilities of BGC823 and SGC7901 cells in dose- and time-dependent manners. CK-induced BGC823 and SGC7901 cells apoptosis and cell cycle arrest in G2 phase by up-regulation of p21 and down-regulation of cdc2 and cyclin B1. Further studies show that CK induces apoptosis in BGC823 and SGC7901 cells mainly through mitochondria-mediated internal pathway, and that CK induces the translocation of nuclear Bid to mitochondria. Finally, we found that CK effectively inhibited the tumour formation of SGC7901 cells in nude mice. Our studies show that CK can inhibit the viabilities and induce apoptosis of human gastric carcinoma cells via Bid-mediated mitochondrial pathway.

p53 facilitates BH3-only BID nuclear export to induce apoptosis in the irrepairable DNA damage response

Over the past decade, the BH3-only BID likes p53, has emerged as a central player in linking death signals through surface death receptors to the core apoptotic mitochondrial pathway and life signals through cell cycle arrest. Recent studies indicate that pro-apoptotic activation of BID may be negatively regulated by its phosphorylation in response to DNA damage. BID itself plays a role in cell cycle checkpoint response, in DNA repair, or in integrating apoptosis and the DNA damage response, which indicate BID is a nuclear-cytoplasmic protein. However, BID does not have any obvious nuclear localization signals (NLS), and only carries nuclear export signals (NES). Mutating BID NES does not affect the nuclear exit of BID, suggesting that BID NES does not seem to function as a NES. Therefore, BID is transported into the nucleus and its export is probably mediated by other NES-carrying proteins. As a well-characterized transcription factor, p53 carries typical NLS and NES. Bid is transcriptionally regulated by p53, and both can be exported from nucleus to the mitochondria in response to DNA damage. Moreover, p53 can, through the interaction with BID in the mitochondria to induce apoptosis. Given the above background, we hypothesize that p53 facilitates BID nuclear export to induce apoptosis in response to irreparable DNA damage.

Pro-apoptotic and anti-proliferative effects of mitofusin-2 via Bax signaling in hepatocellular carcinoma cells

Mitochondrial GTPase mitofusin-2 (Mfn2) is a novel gene that remarkably suppresses the injury-mediated proliferation of vascular smooth muscle cells (VSMCs) and has a potential apoptotic effect via the mitochondrial apoptotic pathway. Hepatocellular carcinoma (HCC) tissues and matched normal tissues were examined for mfn2 expression. HCC cells were infected with adenovirus carrying Mfn2 (Ad-mfn2) or green fluorescent protein (Ad-GFP), used as a control. Short hairpin RNA (shRNA) was formed by shR-mfn2 and shR-Bax to repress mfn2 and Bax transcription, respectively. The effects of mfn2 on cell cycle distribution and apoptosis were measured by flow cytometric analysis. Significant downregulation of mfn2 was observed in HCC tissues compared with nearby normal tissues. Overexpression of mfn2 inhibited HCC cell proliferation and induced apoptosis by increasing the level of active caspase-3 and poly (ADP-ribose) polymerase (PARP) cleavage. Overexpression of mfn2 also induced cytochrome c release to the cytoplasm by enhancing Bax translocation from the cytoplasm to the mitochondrial membrane. Upregulation of mfn2 promoted apoptosis of HCC cells, and this was dramatically suppressed by shR-Bax. Our results show that the mfn2 gene is a potential tumor suppressor target that may significantly promote apoptosis via Bax and may inhibit proliferation in HCC cells. This gene may be an important therapeutic target for the treatment of tumors or hyperproliferative diseases.

Intestinal metabolite compound K of ginseng saponin potently attenuates metastatic growth of hepatocellular carcinoma by augmenting apoptosis via a Bid-mediated mitochondrial pathway

It was recently shown that compound K (CK), an intestinal bacterial metabolite of ginseng saponin, exhibits antihepatocellular carcinoma (HCC) activity, and Bid is a potential drug target for HCC therapy. This paper reports a novel mechanism of CK-induced apoptosis of HCC cells via Bid-mediated mitochondrial pathway. CK dramatically inhibited HCC cells growth in concentration- and time-dependent manners, and a high dose of CK could induce HCC cell apoptotic cell death. Furthermore, the effective dose of CK potently attenuated the subcutaneous tumor growth and spontaneous HCC metastasis in vivo. At the molecular level, immunohistochemical staining revealed that Bid expression in subcutaneous tumor and liver metastasis tissues decreased dramatically in CK-treated groups compared to untreated controls, which also implies that Bid may play a critical role in the growth and progression of HCC. Further study shows that translocation of full-length Bid to the mitochondria from nuclei during cytotoxic apoptosis was associated with the release of cytochrome c from mitochondria, indicating that full-length Bid is sufficient for the activation of mitochondrial cell death pathways in response to CK treatment in HCC cells. Taken together, the results not only reveal a Bid-mediated mitochondrial pathway in HCC cells induced by CK but also suggest that CK may become a potential cytotoxic drug targeting Bid in the prevention and treatment of HCC.

Susceptibility of Hep3B cells in different phases of cell cycle to tBid

tBid is a pro-apoptotic molecule. Apoptosis inducers usually act in a cell cycle-specific fashion. The aim of this study was to elucidate whether effect of tBid on hepatocellular carcinoma (HCC) Hep3B cells was cell cycle phase specific. We synchronized Hep3B cells at G0/G1, S or G2/M phases by chemicals or flow sorting and tested the susceptibility of the cells to recombinant tBid. Cell viability was measured by MTT assay and apoptosis by TUNEL. The results revealed that tBid primarily targeted the cells at G0/G1 phase of cell cycle, and it also increased the cells at the G2/M phase. 5-Fluorouracil (5-FU), on the other hand, arrested Hep3B cells at the G0/G1 phase, but significantly reduced cells at G2/M phase. The levels of cell cycle-related proteins and caspases were altered in line with the change in the cell cycle. The combination of tBid with 5-FU caused more cells to be apoptotic than either agent alone. Therefore, the complementary effect of tBid and 5-FU on different phases of the cell cycle may explain their synergistric effect on Hep3B cells. The elucidation of the phase-specific effect of tBid points to a possible therapeutic option that combines different phase specific agents to overcome resistance of HCC.

Homeostatic functions of BCL-2 proteins beyond apoptosis

Since its introduction in 1930 by physiologist Walter Bradford Cannon, the concept of homeostasis remains the cardinal tenet of biologic regulation. Cells have evolved a highly integrated network of control mechanisms, including positive and negative feedback loops, to safeguard homeostasis in face of a wide range of stimuli. Such control mechanisms ultimately orchestrate cell death, division and repair in a manner concordant with cellular energy and ionic balance to achieve proper biologic fitness. The interdependence of these homeostatic pathways is also evidenced by shared control points that decode intra- and extracellular cues into defined effector responses. As critical control points of the intrinsic apoptotic pathway, the BCL-2 family of cell death regulators plays an important role in cellular homeostasis. The different anti- and pro-apoptotic members of this family form a highly selective network of functional interactions that ultimately governs the permeabilization of the mitochondrial outer membrane and subsequent release of apoptogenic factors such as cytochrome c. The advent of loss- and gain-of-function genetic models for the various BCL-2 family proteins has not only provided important insights into apoptosis mechanisms but also uncovered unanticipated roles for these proteins in other physiologic pathways beyond apoptosis (Fig. 1). Here, we turn our attention to these alternative cellular functions for BCL-2 proteins. We begin with a brief introduction of the cast of characters originally known for their capacity to regulate apoptosis and continue to highlight recent advances that have shaped and reshaped our views on their physiologic relevance in integration of apoptosis with other homeostatic pathways.

BH3-only proteins and their effects on cancer

Apoptosis, a form of cellular suicide is a key mechanism involved in the clearance of cells that are dysfunctional, superfluous or infected. For this reason, the cell needs mechanisms o sense death cues and relay death signals to the apoptotic machinery involved in cellular execution. In the intrinsic apoptotic pathway, a subclass of BCL-2 family proteins called the BH3-onlyproteins are responsible for triggering apoptosis in response to varied cellular stress cues. The mechanisms by which they are regulated are tied to the type of cellular stress they sense. Once triggered, they interact with other BCL-2 family proteins to cause mitochondrial outer membrane permeabilization which in turn results in the activation ofserine proteases necessary for cell killing. Failure to properly sense death cues and relay the death signal can have a major impact on cancer. This chapter will discuss our current models of how BH3-only proteins function as well as their impact on carcinogenesis and cancer treatment.

Induction of apoptosis and cell cycle arrest in human HCC MHCC97H cells with Chrysanthemum indicum extract

AIM: To investigate the effects of Chrysanthemum indicum extract (CIE) on inhibition of proliferation and on apoptosis, and the underlying mechanisms, in a human hepatocellular carcinoma (HCC) MHCC97H cell line.

METHODS: Viable rat hepatocytes and human endothelial ECV304 cells were examined by trypan blue exclusion and MTT assay, respectively, as normal controls. The proliferation of MHCC97H cells was determined by MTT assay. The cellular morphology of MHCC97H cells was observed by phase contrast microscopy. Flow cytometry was performed to analyze cell apoptosis with annexin V/propidium iodide (PI), mitochondrial membrane potential with rhodamine 123 and cell cycle with PI in MHCC97H cells. Apoptotic proteins such as cytochrome C, caspase-9, caspase-3 and cell cycle proteins, including P21 and CDK4, were measured by Western blotting.

RESULTS: CIE inhibited proliferation of MHCC97H cells in a time- and dose-dependent manner without cytotoxicity in rat hepatocytes and human endothelial cells. CIE induced apoptosis of MHCC97H cells in a concentration-dependent manner, as determined by flow cytometry. The apoptosis was accompanied by a decrease in mitochondrial membrane potential, release of cytochrome C and activation of caspase-9 and caspase-3. CIE arrested the cell cycle in the S phase by increasing P21 and decreasing CDK4 protein expression.

CONCLUSION: CIE exerted a significant apoptotic effect through a mitochondrial pathway and arrested the cell cycle by regulation of cell cycle-related proteins in MHCC97H cells without an effect on normal cells. The cancer-specific selectivity shown in this study suggests that the plant extract could be a promising novel treatment for human cancer.

Bax deficiency in mice increases cartilage production during fracture repair through a mechanism involving increased chondrocyte proliferation without changes in apoptosis

This study sought to determine the role of the pro-apoptotic gene, Bax, in fracture healing by comparing femoral fracture healing in Bax knockout (KO) and wild-type C57BL/6J (background strain) mice. Bax KO fractures were larger, had more bone mineral content, had approximately 2-fold larger cartilage area per callus area in the first and second weeks of fracture healing, and showed an increased osteoclast surface area in the third and fourth weeks of fracture healing compared to C57BL/6J fractures. The increased cartilage area in the Bax KO fracture callus was due to increases in number of both pre-hypertropic and hypertropic chondrocytes. TUNEL analysis showed no significant differences in the number of either chondrocyte or non-chondrocyte apoptotic cells between Bax KO and C57BL/6J fractures at 7 or 14 days post-fracture, indicating that the increased number of chondrocytes in Bax KO fractures was not due to reduced apoptosis. Analysis of expression of apoptotic genes revealed that although the expression levels of Bcl-2 and Bcl-xL were not different between the Bax KO and C57BL/6J mice at 7 or 14 days post-fracture, the expression of BH3-domain only Bak and "Bik-like" pro-apoptotic gene increased approximately 1.5-fold and approximately 2-fold, respectively, in Bax KO fractures at 7 and 14 days post-fracture, compared to C57BL/6J fractures, suggesting that up-regulation of the Bak and Bik-like pro-apoptotic genes in Bax KO mice might compensate for the lack of Bax functions in the context of apoptosis. Analysis by in vivo incorporation of bromodeoxyuridine into chondrocytes within the fracture tissues indicated a highly significant increase in chondrocyte proliferation in Bax KO fractures compared to C57BL/6J fractures at day 7. The increased expression of collagen 2alpha1 and 9alpha1 gene in Bax KO fractures during early healing was consistent with an increased chondrocyte proliferation. In conclusion, this study demonstrates for the first time that Bax has an important role in the early stage of fracture healing, and that the increased callus size and cartilage area in Bax KO fractures was due to increased chondrocyte proliferation and not to reduced apoptosis or increased chondrocyte hypertrophy. The unexpected effect of Bax deficiency on chondrocyte proliferation implicates a novel regulatory function for Bax on chondrocyte proliferation during fracture repair.

Different apoptotic pathways induced by zearalenone, T-2 toxin and ochratoxin A in human hepatoma cells

Mycotoxins, secondary metabolites produced by moulds, have been shown to cause diverse toxic effects in animals and are also suspected of disease causation in humans. The present study compares the molecular mechanisms of the toxicity of zearalenone (ZEN), T-2 toxin and ochratoxin A (OTA) in human hepatoma cells HepG2. The three mycotoxins-induced a caspase-dependent mitochondrial apoptotic pathway. The mitochondrial alterations include: bax relocalisation into the mitochondrial outer membrane, loss of the mitochondrial transmembrane potential, PTPC opening, and cytochrome c (but not AIF) release. In the presence of ZEN and T-2 toxin, reactive oxygen species (ROS) level was highly increased at an early stage even before mitochondrial alterations were observed, whereas OTA-induced only O(2)(-) generation among total ROS. This ROS production appears as a consequence of mitochondrial alterations. HepG2 cell treatment with the p53 inhibitor pifithrin-alpha (PFT) and western blot analysis suggested that both ZEN and OTA, but not T-2 toxin, trigger a p53-dependent apoptotic pathway. These results clearly point to a central role of mitochondria in the apoptotic process induced by ZEN, T-2 toxin and OTA and provide new insights into the molecular mechanisms by which these mycotoxins might promote hepatotoxicty.