Effects of valproic acid on the cell cycle and apoptosis through acetylation of histone and tubulin in a scirrhous gastric cancer cell line

Exploring potential biomarkers and lead molecules in gastric cancer by network biology, drug repurposing and virtual screening strategies

Gastric cancer poses a significant global health challenge, necessitating innovative approaches for biomarker discovery and therapeutic intervention. This study employs a multifaceted strategy integrating network biology, drug repurposing, and virtual screening to elucidate and expand the molecular landscape of gastric cancer. We identified and prioritized key genes implicated in gastric cancer by utilizing data from diverse databases and text-mining techniques. Network analysis underscored intricate gene interactions, emphasizing potential therapeutic targets such as CTNNB1, BCL2, TP53, etc, and highlighted ACTB among the top hub genes crucial in disease progression. Drug repurposing on 626 FDA-approved drugs for digestive system-related cancers revealed Norgestimate and Nimesulide as likely top candidates for gastric cancer, validated by molecular docking and dynamics simulations. Further, combinatorial synthesis of scaffold libraries derived from known chemotypes generated 56,160 virtual compounds, of which 76 new compounds were prioritized based on promising binding affinities and interactions at critical residues. Hotspot residue analysis identified GLU 214 and others as essential for ligand binding stability, enhancing compound efficacy and specificity. These findings support the therapeutic potential of targeting beta-actin protein in gastric cancer treatment, suggesting a future for further experimental validation and clinical translation. In conclusion, this study highlights the potential of repurposable drugs and virtual screening which can be used in combination with existing anti-gastric cancer drugs for gastric cancer therapy, emphasizing the role of computational methodologies in drug discovery.

Mechanistic Insights about Sorafenib-, Valproic Acid- and Metformin-Induced Cell Death in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is among the main causes of death by cancer worldwide, representing about 80-90% of all liver cancers. Treatments available for advanced HCC include atezolizumab, bevacizumab, sorafenib, among others. Atezolizumab and bevacizumab are immunological options recently incorporated into first-line treatments, along with sorafenib, for which great treatment achievements have been reached. However, sorafenib resistance is developed in most patients, and therapeutical combinations targeting cancer hallmark mechanisms and intracellular signaling have been proposed. In this review, we compiled evidence of the mechanisms of cell death caused by sorafenib administered alone or in combination with valproic acid and metformin and discussed them from a molecular perspective.

HDAC2 as a Target for developing Anti-cancer Drugs

Histone deacetylases (HDACs) deacetylate histones H3 and H4. An imbalance between histone acetylation and deacetylation can lead to various diseases. HDAC2 is present in the nucleus. It plays a critical role in modifying chromatin structures and regulates the expression of various genes by functioning as a transcriptional regulator. The roles of HDAC2 in tumorigenesis and anti-cancer drug resistance are discussed in this review. Several reports suggested that HDAC2 is a prognostic marker of various cancers. The roles of microRNAs (miRNAs) that directly regulate the expression of HDAC2 in tumorigenesis are also discussed in this review. This review also presents HDAC2 as a valuable target for developing anti-cancer drugs.

Repurposed Drugs in Gastric Cancer

Gastric cancer (GC) is one of the major causes of death worldwide, ranking as the fifth most incident cancer in 2020 and the fourth leading cause of cancer mortality. The majority of GC patients are in an advanced stage at the time of diagnosis, presenting a poor prognosis and outcome. Current GC treatment approaches involve endoscopic detection, gastrectomy and chemotherapy or chemoradiotherapy in an adjuvant or neoadjuvant setting. Drug development approaches demand extreme effort to identify molecular mechanisms of action of new drug candidates. Drug repurposing is based on the research of new therapeutic indications of drugs approved for other pathologies. In this review, we explore GC and the different drugs repurposed for this disease.

Manipulating Histone Acetylation Leads to Antitumor Effects in Hemangiosarcoma Cells

Canine hemangiosarcoma (HSA) is a malignant tumor derived from endothelial cells. No effective treatment has yet been developed because of the lack of understanding of its pathogenesis. Histone acetylation, an epigenetic modification, is highly associated with cancer pathogenesis. Manipulating histone acetylation by histone deacetylase inhibitors (HDACi) or bromodomain and extraterminal domain inhibitors (BETi) is one approach to treat various cancers. However, the role of histone acetylation in HSA remains unknown. This study aimed to investigate how histone acetylation functions in HSA pathogenesis using two HDACi, suberanilohydroxamic acid (SAHA) and valproic acid (VPA), and one BETi, JQ1, in vitro and in vivo. Histone acetylation levels were high in cell lines and heterogeneous in clinical cases. SAHA and JQ1 induced apoptosis in HSA cell lines. HSA cell lines treated with SAHA and VPA upregulated inflammatory-related genes and attracted macrophage cell line RAW264 cells, which suggests that SAHA and VPA can affect immune responses. JQ1 stimulated autophagy and inhibited the cell cycle in HSA cell lines. Finally, we demonstrated that JQ1 suppressed HSA tumor cell proliferation in vivo although SAHA and VPA did not affect tumor growth. These results suggest that BETi can be alternative drugs for HSA treatment. Although further research is required, our study indicated that dysregulation of histone acetylation is likely to be involved in HSA malignancy. This article is protected by copyright. All rights reserved.

Anticancer Effects of Valproic Acid via Regulation of Epigenetic Mechanisms in Non-small-cell Lung Cancer A549 Cell Line

Epigenetic mechanisms are the most important factors contributing to both the development and metastasis of cancer cells. We aimed to scrutinize the role of epigenetic alternations of genes involved in cancer metastasis, including CD44v6 (metastasis indicator) and Nm23-H1 (a novel tumor suppressor), in the A549 lung cancer cell line. The A549 cells were cultured in the DMEM medium. Valproic acid (VPA) was used as a histone deacetylase inhibitor. Caspase-3 activity was assessed by adding DEVD-pNA substrate to the cell lysate. Gene expression was determined by real-time PCR. Finally, protein expression was assessed by western blot. The results showed that VA significantly decreased the expression of the CD44v6 gene and its protein level. This was further accompanied by lower expressions of MMP-2 and MMP-9 genes. On the other hand, the expression of Nm23-H1 and its protein were significantly increased in the cells accompanied by higher activity of caspase-3 (P ˂ 0.05). Our results showed that epigenetic regulation of CD44v6, Nm23-H1, MMP-2, and MMP-9 might be involved in the pathogenesis and metastasis of lung cancer. Therefore, the use of histone deacetylase inhibitors can be effective in the suppression of metastases and the treatment of these tumors.

Proteomic Studies of Primary Acute Myeloid Leukemia Cells Derived from Patients Before and during Disease-Stabilizing Treatment Based on All-Trans Retinoic Acid and Valproic Acid

All-trans retinoic acid (ATRA) and valproic acid (VP) have been tried in the treatment of non-promyelocytic variants of acute myeloid leukemia (AML). Non-randomized studies suggest that the two drugs can stabilize AML and improve normal peripheral blood cell counts. In this context, we used a proteomic/phosphoproteomic strategy to investigate the in vivo effects of ATRA/VP on human AML cells. Before starting the combined treatment, AML responders showed increased levels of several proteins, especially those involved in neutrophil degranulation/differentiation, M phase regulation and the interconversion of nucleotide di- and triphosphates (i.e., DNA synthesis and binding). Several among the differentially regulated phosphorylation sites reflected differences in the regulation of RNA metabolism and apoptotic events at the same time point. These effects were mainly caused by increased cyclin dependent kinase 1 and 2 (CDK1/2), LIM domain kinase 1 and 2 (LIMK1/2), mitogen-activated protein kinase 7 (MAPK7) and protein kinase C delta (PRKCD) activity in responder cells. An extensive effect of in vivo treatment with ATRA/VP was the altered level and phosphorylation of proteins involved in the regulation of transcription/translation/RNA metabolism, especially in non-responders, but the regulation of cell metabolism, immune system and cytoskeletal functions were also affected. Our analysis of serial samples during the first week of treatment suggest that proteomic and phosphoproteomic profiling can be used for the early identification of responders to ATRA/VP-based treatment.

Serum-Free Medium for Recombinant Protein Expression in Chinese Hamster Ovary Cells

At present, nearly 70% of recombinant therapeutic proteins (RTPs) are produced by Chinese hamster ovary (CHO) cells, and serum-free medium (SFM) is necessary for their culture to produce RTPs. In this review, the history and key components of SFM are first summarized, and its preparation and experimental design are described. Some small molecule compound additives can improve the yield and quality of RTP. The function and possible mechanisms of these additives are also reviewed here. Finally, the future perspectives of SFM use with CHO cells for RTP production are discussed.

Refocusing the Use of Psychiatric Drugs for Treatment of Gastrointestinal Cancers

Gastrointestinal cancers (GICs) are the most common human tumors worldwide. Treatments have limited effects, and increasing global cancer burden makes it necessary to investigate alternative strategies such as drug repurposing. Interestingly, it has been found that psychiatric drugs (PDs) are promising as a new generation of cancer chemotherapies due to their anti-neoplastic properties. This review compiles the state of the art about how PDs have been redirected for cancer therapeutics in GICs. PDs, especially anti-psychotics, anti-depressants and anti-epileptic drugs, have shown effects on cell viability, cell growth, inhibition of proliferation (cell cycle arrest), apoptosis promotion by caspases activation or cytochrome C release, production of reactive oxygen species (ROS) and nuclear fragmentation over esophageal, gastric, colorectal, liver and pancreatic cancers. Additionally, PDs can inhibit neovascularization, invasion and metastasis in a dose-dependent manner. Moreover, they can induce chemosensibilization to 5-fluorouracil and cisplatin and can act synergistically with anti-neoplastic drugs such as gemcitabine, paclitaxel and oxaliplatin. All anti-cancer activities are given by activation or inhibition of pathways such as HDAC1/PTEN/Akt, EGFR/ErbB2/ErbB3, and PI3K/Akt; PI3K-AK-mTOR, HDAC1/PTEN/Akt; Wnt/β-catenin. Further investigations and clinical trials are needed to elucidate all molecular mechanisms involved on anti-cancer activities as well as adverse effects on patients.

Embryo-derived teratoma in vitro biological system reveals antitumor and embryotoxic activity of valproate

Antiepileptic/teratogen valproate (VPA) is a histone deacetylase inhibitor/epigenetic drug proposed for the antitumor therapy where it is generally crucial to target poorly or undifferentiated cells to prevent a recurrence. Transplanted rodent gastrulating embryos‐proper (primitive streak and three germ layers) are the source of teratoma/teratocarcinoma tumors. Human primitive‐streak remnants develop sacrococcygeal teratomas that may recur even when benign (well differentiated). To screen for unknown VPA impact on teratoma‐type tumors, we used original 2‐week embryo‐derived teratoma in vitro biological system completed by a spent media metabolome analysis. Gastrulating 9.5‐day‐old rat embryos‐proper were cultivated in Eagle's minimal essential medium (MEM) with 50% rat serum (controls) or with the addition of 2 mmVPA. Spent media metabolomes were analyzed by FTIR. Compared to controls, VPA acetylated histones; significantly diminished overall teratoma growth, impaired survival, increased the apoptotic index, and decreased proliferation index and incidence of differentiated tissues (e.g., neural tissue). Control teratomas continued to grow and differentiate for 14 days in isotransplants in vivo, but in vitro VPA‐treated teratomas resorbed. Principal component analysis of FTIR results showed that spent media metabolomes formed well‐separated clusters reflecting the treatment and day of cultivation. In metabolomes of VPA‐treated teratomas, we found elevation of previously described histone acetylation biomarkers [amide I α‐helix and A(CH₃)/A(CH₂)]) with apoptotic biomarkers within the amide I region for β‐sheets, and unordered and CH₂ vibrations of lipids. VPA may be proposed for therapy of the undifferentiated component of teratoma tumors and this biological system completed by metabolome analysis, for a faster dual screening of antitumor/embryotoxic agents.

Synergistic induction of apoptosis in a cell model of human leukemia K562 by nitroglycerine and valproic acid

Nitroglycerin (NG), a nitric oxide donor, and valproic acid (VPA), an inhibitor of histone deacetylases, have impressive effects on numerous cancer cell lines. This study intended to evaluate synergistic effects of NG and VPA on cell viability and apoptosis in K562 cells. K562 cells were cultured in RPMI-1640 supplemented with 10 % heat-inactivated FBS. They were treated with different doses of NG, VPA and cisplatin for 24, 48, and 72 h, and MTT assay was performed to analyze cell viability. Also, Peripheral blood mononuclear cells (PBMC) were cultured in RPMI-1640 media and incubated with NG (200 μM), VAP (100 μM), NG+VPA (150 μM) and cisplatin (8 μM) to evaluate cytotoxicity. IC₅₀ of the drugs, when they were applied separately and in combination, were calculated using the COMPUSYN software. DNA electrophoresis, TUNEL assay, and Hoechst staining were performed to investigate apoptosis induction. RT-PCR was used for the evaluation of apoptotic genes expression. The results of the MTT assay showed that cell viability decreased at all applied doses of NG and VPA. It was noticed that the cytotoxic effects of these drugs were dose- and time-dependent. Based on the COMPUSYN output, the combination of the drugs (VPA and NG) in a certain ratio concentration synergistically decreased cell viability. Cisplatin significantly decreased cell viability of PBMCs and K562 cells. Also, the combination drug had cytotoxic effect and significantly reduced viability of K562 cells compared with PBMCs and control cells. In the target cells treated with this combination, Bax and caspase-3 expression increased but Bcl-2 expression decreased. These results suggest that NG, VPA, and their combination decreased cell viability and induced apoptosis via the intrinsic apoptotic pathway. This study suggests that this combination therapy can be considered for further evaluation as an effective chemotherapeutic strategy for patients with chronic myeloid leukemia.

Effect of valproic acid on cisplatin-resistant ovarian cancer cell lines

Background and aims: Platinum resistance has been one of the most important problems in the management of ovarian cancer. The effects of various chemotherapeutic agents are limited in patients with platinum resistance. Therefore, developing new anticancer drugs that can improve the effect of currently used cytostatics is critical. The current study investigated the effects of valproic acid (VPA) alone and in combination with cisplatin on ovarian cancer cells. Methods: In this experimental study, the human ovarian cancer cell lines (A2780-S and A2780-CP) were grown in RPMI-1640 medium in appropriate culture conditions. The cells were treated with various concentrations of cisplatin (0.15-400 µg/mL) or VPA (10-2000 µg/mL) and were incubated for 24, 48, and 72 hours. Moreover, A2780 cells were co-treated with different concentrations of cisplatin and VPA for 48 hours. Afterward, cell viability was investigated using MTT assay. GraphPad Prism statistical software was used for the data analysis and ANOVA and Duncan’s test were conducted. Results: A dose- and time-dependent reduction was observed in cell viability following the treatment with cisplatin or VPA. Moreover, cotreatment of the A2780 cells with cisplatin and VPA resulted in a significantly greater inhibition of cell viability compared to the treatment with either agent alone. Conclusion: Overall, it can be argued that VPA does not only cause inhibition of proliferation and induction of apoptosis in ovarian cancer cells but also helps to enhance the antiproliferative effects of cisplatin and results in the increased susceptibility to cisplatin in resistant cells. VPA may therefore be used to treat cancer in the future.

Histone Deacetylase Inhibitor Modulates NKG2D Receptor Expression and Memory Phenotype of Human Gamma/Delta T Cells Upon Interaction With Tumor Cells

The functional plasticity and anti-tumor potential of human γδ T cells have been widely studied. However, the epigenetic regulation of γδ T-cell/tumor cell interactions has been poorly investigated. In the present study, we show that treatment with the histone deacetylase inhibitor Valproic acid (VPA) significantly enhanced the expression and/or release of the NKG2D ligands MICA, MICB and ULBP-2, but not ULBP-1 in the pancreatic carcinoma cell line Panc89 and the prostate carcinoma cell line PC-3. Under in vitro tumor co-culture conditions, the expression of full length and the truncated form of the NKG2D receptor in γδ T cells was significantly downregulated. Furthermore, using a newly established flow cytometry-based method to analyze histone acetylation (H3K9ac) in γδ T cells, we showed constitutive H3K9aclow and inducible H3K9achigh expression in Vδ2 T cells. The detailed analysis of H3K9aclow Vδ2 T cells revealed a significant reversion of TEMRA to TEM phenotype during in vitro co-culture with pancreatic ductal adenocarcinoma cells. Our study uncovers novel mechanisms of how epigenetic modifiers modulate γδ T-cell differentiation during interaction with tumor cells. This information is important when considering combination therapy of VPA with the γδ T-cell-based immunotherapy for the treatment of certain types of cancer.

N-acetylcysteine decreases malignant characteristics of glioblastoma cells by inhibiting Notch2 signaling

BACKGROUND

Glioblastomas multiforme (GBM) is the most devastating primary intracranial malignancy lacking effective clinical treatments. Notch2 has been established to be a prognostic marker and probably involved in GBM malignant progression. N-acetylcysteine (NAC), a precursor of intracellular glutathione (GSH), has been widely implicated in prevention and therapy of several cancers. However, the role of NAC in GBM remains unclear and the property of NAC independent of its antioxidation is largely unknown.

METHODS

The mRNA and protein levels of Notch family and other related factors were detected by RT-PCR and western blot, respectively. In addition, intracellular reactive oxygen species (ROS) was measured by flow cytometry-based DCFH-DA. Moreover, cell viability was assessed by CCK8 and cell cycle was analyzed by flow cytometry-based PI staining. The level of apoptosis was checked by flow cytometry-based Annexin V/PI. Cell migration and invasion were evaluated by wound healing and transwell invasion assays. At last, U87 Xenograft model was established to confirm whether NAC could restrain the growth of tumor.

RESULTS

Our data showed that NAC could decrease the protein level of Notch2. Meanwhile, NAC had a decreasing effect on the mRNA and protein levels of its downstream targets Hes1 and Hey1. These effects caused by NAC were independent of cellular GSH and ROS levels. The mechanism of NAC-mediated Notch2 reduction was elucidated by promoting Notch2 degradation through Itch-dependent lysosome pathway. Furthermore, NAC could prevent proliferation, migration, and invasion and might induce apoptosis in GBM cells via targeting Notch2. Significantly, NAC could suppress the growth of tumor in vivo.

CONCLUSIONS

NAC could facilitate Notch2 degradation through lysosomal pathway in an antioxidant-independent manner, thus attenuating Notch2 malignant signaling in GBM cells. The remarkable ability of NAC to inhibit cancer cell proliferation and tumor growth may implicate a novel application of NAC on GBM therapy.

Valproic acid treatment response in vitro is determined by TP53 status in medulloblastoma

PURPOSE

Histone deacetylate inhibitors (HDACi), as valproic acid (VA), have been reported to enhance efficacy and to prevent drug resistance in some tumors, including medulloblastoma (MB). In the present study, we investigated VA role, combined to cisplatin (CDDP) in cell viability and gene expression of MB cell lines.

METHODS

Dose-response curve determined IC₅₀ values for each treatment: (1) VA single, (2) CDDP single, and (3) VA and CDDP combined. Cytotoxicity and flow cytometry evaluated cell viability after exposure to treatments. Quantitative PCR evaluated gene expression levels of AKT, CTNNB1, GLI1, KDM6A, KDM6B, NOTCH2, PTCH1, and TERT, before and after treatment. Besides, we performed next-generation sequencing (NGS) for PTCH1, TERT, and TP53 genes.

RESULTS

The most effective treatment to reduce viability was combined for D283MED and ONS-76; and CDDP single for DAOY cells (p < 0.0001). TERT, GLI1, and AKT genes were overexpressed after treatments with VA. D283MED and ONS-76 cells presented variants in TERT and PTCH1, respectively and DAOY cell line presented a TP53 mutation.

CONCLUSIONS

MB tumors belonging to SHH molecular subgroup, with TP53^MUT, would be the ones that present high risk in relation to VA use during the treatment, while TP53^WT MBs can benefit from VA therapy, both SHH and groups 3 and 4. Our study shows a new perspective about VA action in medulloblastoma cells, raising the possibility that VA may act in different patterns. According to the genetic background of MB cell, VA can stimulate cell cycle arrest and apoptosis or induce resistance to treatment via signaling pathways activation.

Therapeutic positioning of secretory acetylated APE1/Ref-1 requirement for suppression of tumor growth in triple-negative breast cancer in vivo

Triple-negative breast cancer (TNBC) represents a relatively small proportion of all BCs but a relatively large proportion of BC-related death. Thus, more effective therapeutic strategies are needed for the management of TNBC. We demonstrated that the stimulation of apoptosis by the binding of secreted acetylated-apurinic apyrimidinic endonuclease 1/redox factor-1 (Ac-APE1/Ref-1) to the receptor for advanced glycation end products (RAGE) was essential for TNBC cell death in response to hyperacetylation. The aim of the present study was to assess the potential therapeutic efficacy of secretory Ac-APE1/Ref-1 in orthotopic TNBC xenografts in vivo. We found that hyperacetylation in xenografts caused secretion of Ac-APE1/Ref-1 into the blood, where the factor bound directly to RAGE in hyperacetylated tumor tissues. Hyperacetylation in the TNBC xenografts induced strong inhibition of tumor growth and development, leading to apoptotic cell death, accompanied by increased RAGE expression and generation of reactive oxygen species. Tissues exhibited markedly higher counts of apoptotic bodies, a reduced proliferation index, and reduced neovascularization compared with control tumors. Ac-APE1/Ref-1-stimulated apoptosis was markedly reduced in RAGE-knockdown tumors compared with RAGE-overexpressing tumors, even in the presence of hyperacetylation. The function of secreted Ac-APE1/Ref-1 was confirmed in other hyperacetylated TNBCs xenografts using BT-549 and MDA-MB-468 cells, demonstrating its relevance as an anti-cancer molecule.

Expression of non-secreted IL-4 is associated with HDAC inhibitor-induced cell death, histone acetylation and c-Jun regulation in human gamma/delta T-cells

Previously, the expression of a non-secreted IL-4 variant (IL-4δ₁₃) has been described in association with apoptosis and age-dependent Th2 T-cell polarization. Signaling pathways involved in this process have so far not been studied. Here we report the induction of IL-4δ₁₃ expression in human γδ T-cells upon treatment with a sublethal dose of histone deacetylase (HDACi) inhibitor valproic acid (VPA). Induction of IL-4δ₁₃ was associated with increased cytoplasmic IL-4Rα and decreased IL-4 expression, while mRNA for mature IL-4 was concomitantly down-regulated. Importantly, only the simultaneous combination of apoptosis and necroptosis inhibitors prevented IL-4δ₁₃ expression and completely abrogated VPA-induced global histone H3K9 acetylation mark. Further, our work reveals a novel involvement of transcription factor c-Jun in the signaling network of IL-4, HDAC1, caspase-3 and mixed lineage kinase domain-like protein (MLKL). This study provides novel insights into the effects of epigenetic modulator VPA on human γδ T-cell differentiation.

Low-dose valproic acid with low-dose gemcitabine augments MHC class I-related chain A/B expression without inducing the release of soluble MHC class I-related chain A/B

To improve natural killer group 2 member D (NKG2D)-dependent cytotoxicity, the inhibition of cleavage and release of major histocompatibility complex class 1-related chain (MIC) molecules from the tumor surface are required. Valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, is able to induce cell-surface MICA/B on tumor cells. In the present study, the ability of VPA and gemcitabine (GEM) to upregulate MICA/B in pancreatic cancer cells was investigated, resulting in the inhibition of cleavage and release of MIC molecules from the tumor surface. Flow cytometry was used to quantify MICA/B expression in six human pancreatic cancer lines. Functional cytotoxic activity of γδT cells against pancreatic cancer cells treated with VPA and GEM was determined using cytotoxicity assays. At low doses of VPA (0.7 mM) and GEM (0.001 µM), which did not induce tumor growth alterations, the agents individually increased cell-surface MICA/B expression in MICA/B-positive cell lines, but not in the MICA/B-negative cell line. Furthermore, the combination of VPA and GEM synergistically induced cell-surface MICA/B expression. In MICA/B-positive cell lines, the increase in MICA/B expression was dependent on VPA concentration. The combination of low-dose VPA and GEM enhanced the susceptibility of the PANC-1 cell line to γδT cell-mediated tumor cell lysis. It was observed that soluble MIC was released from PANC-1 in the culture supernatant following treatment with GEM. However, the combination of low-dose VPA with low-dose GEM increased MICA/B expression without inducing soluble MIC, resulting in enhanced tumor cell lysis. The results of the present study suggest that the combined administration of low-dose VPA with low-dose GEM has the potential to enhance the therapeutic effects of immunotherapy in pancreatic cancer. Furthermore, it is proposed that the combination acts, in part, by upregulating MICA/B and prevents soluble MIC from being released.

A Comparative Analysis of Drug-Induced Hepatotoxicity in Clinically Relevant Situations

Drug-induced toxicity is a significant problem in clinical care. A key problem here is a general understanding of the molecular mechanisms accompanying the transition from desired drug effects to adverse events following administration of either therapeutic or toxic doses, in particular within a patient context. Here, a comparative toxicity analysis was performed for fifteen hepatotoxic drugs by evaluating toxic changes reflecting the transition from therapeutic drug responses to toxic reactions at the cellular level. By use of physiologically-based pharmacokinetic modeling, in vitro toxicity data were first contextualized to quantitatively describe time-resolved drug responses within a patient context. Comparatively studying toxic changes across the considered hepatotoxicants allowed the identification of subsets of drugs sharing similar perturbations on key cellular processes, functional classes of genes, and individual genes. The identified subsets of drugs were next analyzed with regard to drug-related characteristics and their physicochemical properties. Toxic changes were finally evaluated to predict both molecular biomarkers and potential drug-drug interactions. The results may facilitate the early diagnosis of adverse drug events in clinical application.

Liver toxicity may occur at drug levels above the therapeutic range and is thus a crucial problem in clinical care. However, the cellular changes induced by drug administration of therapeutic and toxic doses in humans are still not well understood. We here coupled patient-specific drug concentration-time profiles following oral administration of therapeutic and toxic doses with in vitro drug response data to predict toxic changes that quantitatively reflect the transition from desired drug effects to undesired toxic reactions. These toxic changes were comparatively evaluated for fifteen hepatotoxic drugs to identify subsets of drugs, which show similar drug effects on key cellular processes, functional classes of genes, and individual genes, respectively. In addition, analyzing toxic changes for individual genes allowed the prediction of molecular biomarkers and potential drug-drug interactions. Our results may hence support the early diagnosis of liver toxicity in clinical care in the future and may, moreover, help to assess potential risks of drug combination therapies.

Paclitaxel plus valproic acid versus paclitaxel alone as second- or third-line therapy for advanced gastric cancer: a randomized Phase II trial

Background

Weekly paclitaxel (wPTX) is the preferred second-line chemotherapy for gastric cancer in Japan. Histone deacetylase inhibitors have been shown to decrease proliferation through cell-cycle arrest, differentiation, and apoptosis in gastric cancer cells. One histone deacetylase inhibitor, valproic acid (VPA), also inhibits tumor growth by inducing apoptosis and enhances the efficacy of paclitaxel (PTX), shown in a murine gastric cancer model. This Phase II trial was designed to evaluate the benefits of adding VPA to wPTX in patients with gastric cancer refractory to first-line treatment with fluoropyrimidine.

Patients and methods

The patients were randomly assigned in a 1:1 ratio to receive PTX 80 mg/m² intravenously on days 1, 8, and 15, every 4 weeks, or a dose of PTX plus VPA taken everyday at 7.5 mg/kg twice daily. Random assignment was carried out at the data center with a minimization method adjusted by the Eastern Cooperative Oncology Group performance status (0–1 vs 2), prior chemotherapy (first-line vs second-line), and measurable lesions (presence vs absence). The primary end point was the overall survival (OS) rate, and the secondary end points were the progression-free survival rate and safety analysis.

Results

Sixty-six patients were randomly assigned to receive wPTX (n=33) or wPTX plus VPA (n=33). The median OS was 9.8 months in the wPTX group and 8.7 months in the wPTX plus VPA group (hazard ratio 1.19; 95% CI 0.702–2.026; P=0.51). The median progression-free survival was 4.5 months in the wPTX group and 3.0 months in the wPTX plus VPA group (hazard ratio 1.29; 95% CI 0.753–2.211; P=0.35). Grade 3–4 adverse events were neutropenia (3.1%), pneumonia (1.6%), liver injury (1.6%), brain infarction (1.6%), and rupture of aorta (1.6%).

Conclusion

No statistically significant difference was observed between wPTX and wPTX plus VPA for OS.

Effects of valproic acid and pioglitazone on cell cycle progression and proliferation of T-cell acute lymphoblastic leukemia Jurkat cells

OBJECTIVES

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematologic malignant tumor. Administration of chemical compounds influencing apoptosis and T cell development has been discussed as promising novel therapeutic strategies. Valproic acid (VPA) as a recently emerged anti-neoplastic histone deacetylase (HDAC) inhibitor and pioglitazone (PGZ) as a high-affinity peroxisome proliferator-activated receptor-gamma (PPARγ) agonist have been shown to induce apoptosis and cell cycle arrest in different studies. Here, we aimed to investigate the underlying molecular mechanisms involved in anti-proliferative effects of these compounds on human Jurkat cells.

MATERIALS AND METHODS

Treated cells were evaluated for cell cycle progression and apoptosis using flowcytometry and MTT viability assay. Real-time RT-PCR was carried out to measure the alterations in key genes associated with cell death and cell cycle arrest.

RESULTS

Our findings illustrated that both VPA and PGZ can inhibit Jurkat E6.1 cells in vitro after 24 hr; however, PGZ 400 μM presents the most anti-proliferative effect. Interestingly, treated cells have been arrested in G2/M with deregulated cell division cycle 25A (Cdc25A) phosphatase and cyclin-dependent kinase inhibitor 1B (CDKN1B or p27) expression. Expression of cyclin D1 gene was inhibited when DNA synthesis entry was declined. Cell cycle deregulation in PGZ and VPA-exposed cells generated an increase in the proportion of aneuploid cell population, which has not reported before.

CONCLUSION

These findings define that anti-proliferative effects of PGZ and VPA on Jurkat cell line are mediated by cell cycle deregulation. Thus, we suggest PGZ and VPA may relieve potential therapeutic application against apoptosis-resistant malignancies.

Novel molecular triggers underlie valproate-induced liver injury and its alleviation by the omega-3 fatty acid DHA: role of inflammation and apoptosis

Background/Aim

Hepatic injury is a hallmark adverse reaction to Valproate (VPA), a common used drug in the management of numerous CNS disorders, including epilepsy. DHA has a myriad of health benefits, including renal- and hepato-protective effects. Unfortunately, however, the underpinnings of such liver-pertinent VPA- and DHA-actions remain largely undefined. Accordingly, this study attempted to unveil the cellular and molecular triggers whereby VPA evokes, while DHA abates, hepatotoxicity.

Methods

We evaluated activity and/or expression of cellular markers of oxidative stress, inflammation, and apoptosis in rat liver, following treatment with VPA (500 mg/kg/day) with and without concurrent treatment with DHA (250 mg/kg/day) for two weeks.

Results and conclusion

VPA promoted hepatic oxidative stress as evidenced by enhancing activity/expression of NADPH-oxidase and its subunits, a ROS-generator, and by accumulation of lipid-peroxides. Moreover, VPA enhanced hepatic phosphorylation/activation of mitogen-activated protein kinase (MAPK), and expression of cyclooxygenase-2(COX-2), as proinflammatory signals. Besides, VPA promoted hepatocellular apoptosis, as attested by enhanced expression of cleaved caspase-9 and increased number of TUNEL-positive hepatocytes. Lastly, VPA upregulated levels of hypoxia-inducible factor-1-alpha (HIF-1α), a multifaceted modulator of hepatocytic biology, and activity of its downstream antioxidant enzyme heme-oxygenase-1(HO-1). These changes were significantly blunted by co-administration of DHA. Our findings demonstrate that VPA activated NADPH-oxidase and HIF-1α to induce oxidative-stress and hypoxia as initiators of hepatic injury. These changes were further aggravated by up-regulation of inflammatory (MAPK and COX-2) and apoptotic cascades, but could be partly lessened by HO-1 activation. Concurrent administration of DHA mitigated all VPA-induced anomalies.

Randomized Phase II trial of paclitaxel plus valproic acid vs paclitaxel alone as second-line therapy for patients with advanced gastric cancer

The standard regimen of second-line chemotherapy for patients with unresectable gastric cancer has not been established. However, weekly paclitaxel (wPTX) has become the preferable second-line chemotherapy in Japan. Histone deacetylase (HDAC) inhibitors have been shown to have antiproliferative activity through cell-cycle arrest, differentiation, and apoptosis in gastric cancer cells. One HDAC inhibitor, valproic acid (VPA), also inhibits tumor growth by inducing apoptosis, and enhances the efficacy of paclitaxel in a mouse xenograft model of gastric cancer. wPTX plus VPA as a second-line chemotherapy is expected to improve survival in gastric cancer patients. A multicenter randomized Phase II study was conducted to compare the effects of wPTX plus VPA and wPTX alone. A total of 66 patients participated in this study. The primary end point of the study was overall survival, and secondary end points were progression-free survival, response rate, and assessment of peripheral neuropathy.

Trichostatin A, a histone deacetylase inhibitor, suppresses proliferation and promotes apoptosis of esophageal squamous cell lines

Histone deacetylase (HDAC)‑mediated epigenetic modification plays crucial roles in numerous biological processes, including cell cycle regulation, cell proliferation and apoptosis. HDAC inhibitors demonstrate antitumor effects in various cancers, including glioblastoma and breast cancer. HDAC inhibitors are therefore promising antitumor drugs for these tumors. The tumorigenesis and development of esophageal squamous cell carcinoma (ESCC) involve genetic and epigenetic mechanisms. However, the effects of the HDAC inhibitor on ESCC are not fully investigated. In the present study, ESCC cells were treated with trichostatin A (TSA) and its antitumor effects and related mechanisms were investigated. The results indicated that TSA suppressed the proliferation of ESCCs and caused G1 phase arrest by inducing the expression of p21 and p27. TSA also induced cell apoptosis by enhancing the expression of pro‑apoptotic protein Bax and decreasing the expression of anti‑apoptotic protein Bcl‑2. Furthermore, TSA inhibited the expression of phosphatidylinositol‑3‑kinase (PI3K) and reduced the phosphorylation of Akt and extracellular signal‑regulated kinase (ERK)1/2 in EC9706 and EC1 cell lines. High levels of acetylated histone H4 were detected in TSA‑treated ESCC cell lines. Overall, these results indicate that TSA suppresses ESCC cell growth by inhibiting the activation of the PI3K/Akt and ERK1/2 pathways. TSA also promotes cell apoptosis through epigenetic regulation of the expression of apoptosis‑related protein.

Histone deacetylase 8 is deregulated in urothelial cancer but not a target for efficient treatment

Background

Previous studies have shown that class-I histone deacetylase (HDAC) 8 mRNA is upregulated in urothelial cancer tissues and urothelial cancer cell lines compared to benign controls. Using urothelial cancer cell lines we evaluated whether specific targeting of HDAC8 might be a therapeutic option in bladder cancer treatment.

Methods

We conducted siRNA-mediated knockdown and specific pharmacological inhibition of HDAC8 with the three different inhibitors compound 2, compound 5, and compound 6 in several urothelial carcinoma cell lines with distinct HDAC8 expression profiles. Levels of HDAC and marker proteins were determined by western blot analysis and mRNA levels were measured by quantitative real-time PCR. Cellular effects of HDAC8 suppression were analyzed by ATP assay, flow cytometry, colony forming assay and migration assay.

Results

Efficient siRNA-mediated knockdown of HDAC8 reduced proliferation up to 45%. The HDAC8 specific inhibitors compound 5 and compound 6 significantly reduced viability of all urothelial cancer cell lines (IC₅₀ 9 – 21 μM). Flow cytometry revealed only a slight increase in the sub-G1 fraction indicating a limited induction of apoptosis. Expression of thymidylate synthase was partly reduced; PARP-cleavage was not detected. The influence of the pharmacological inhibition on clonogenic growth and migration show a cell line- and inhibitor-dependent reduction with the strongest effects after treatment with compound 5 and compound 6.

Conclusions

Deregulation of HDAC8 is frequent in urothelial cancer, but neither specific pharmacological inhibition nor siRNA-mediated knockdown of HDAC8 impaired viability of urothelial cancer cell lines in a therapeutic useful manner. Accordingly, HDAC8 on its own is not a promising drug target in bladder cancer.

Valproic acid, an anti-epileptic drug and a histone deacetylase inhibitor, in combination with proteasome inhibitors exerts antiproliferative, pro-apoptotic and chemosensitizing effects in human colorectal cancer cells: underlying molecular mechanisms

Although the therapeutic efficacy of valproic acid (VPA) has been observed in patients with solid tumors, the very high concentration required to induce antitumor activity limits its clinical utility. The present study focused on the development of combined molecular targeted therapies using VPA and proteasome inhibitors (PIs: MG132, PI-1 and PR-39) to determine whether this combination of treatments has synergistic anticancer and chemosensitizing effects against colorectal cancer. Furthermore, the potential molecular mechanisms of action of the VPA/PI combinations were evaluated. The effects of VPA in combination with PIs on the growth of colorectal cancer cells were assessed with regard to proliferation, cell cycle, apoptosis, reactive oxygen species (ROS) generation and the expression of genes that control the cell cycle, apoptosis and pro-survival/stress-related pathways. Treatment with combinations of VPA and PIs resulted in an additive/synergistic decrease in colorectal cancer cell proliferation compared to treatment with VPA or PIs alone. The combination treatment was associated with a synergistic increase in apoptosis and in the number of cells arrested in the S phase of the cell cycle. These events were associated with increased ROS generation, pro-apoptotic gene expression and stress-related gene expression. These events were also associated with the decreased expression of anti-apoptotic genes and pro-survival genes. The combination of VPA with MG132 or PI-1 enhanced the chemosensitivity of the SW1116 (29-185‑fold) and SW837 (50-620-fold) colorectal cancer cells. By contrast, the combination of VPA/PR-39 induced a pronounced increase in the chemosensitivity of the SW837 (16-54-fold) colorectal cancer cells. These data provide a rational basis for the clinical use of this combination therapy for the treatment of colorectal cancer.

Sodium valproate induces cell senescence in human hepatocarcinoma cells

Hepatocarcinogenesis is associated with epigenetic changes, including histone deacetylases (HDACs). Epigenetic modulation by HDAC inhibition is a potentially valuable approach for hepatocellular carcinoma treatment. In present study, we evaluated the anticancer effects of sodium valproate (SVP), a known HDAC inhibitor, in human hepatocarcinoma cells. The results showed SVP inhibited the proliferation of Bel-7402 cells in a dose-dependent manner. Low dose SVP treatment caused a large and flat morphology change, positive SA-β-gal staining, and G0/G1 phase cell cycle arrest in human hepatocarcinoma cells. Low dose SVP treatment also increased acetylation of histone H3 and H4 on p21 promoter, accompanied by up-regulation of p21 and down-regulation of RB phosphorylation. These observations suggested that a low dose of SVP could induce cell senescence in hepatocarcinoma cells, which might correlate with hyperacetylation of histone H3 and H4, up-regulation of p21, and inhibition of RB phosphorylation. Since the effective concentration inducing cell senescence in hepatocarcinoma cells is clinically available, whether a clinical dose of SVP could induce cell senescence in clinical hepatocarcinoma is worthy of further study.

Lipopolysaccharide prevents valproic acid-induced apoptosis via activation of nuclear factor-κB and inhibition of p53 activation

The effect of lipopolysaccharide (LPS) on valproic acid (VPA)-induced cell death was examined by using mouse RAW 264.7 macrophage cells. LPS inhibited the activation of caspase 3 and poly (ADP-ribose) polymerase and prevented VPA-induced apoptosis. LPS inhibited VPA-induced p53 activation and pifithrin-α as a p53 inhibitor as well as LPS prevented VPA-induced apoptosis. LPS abolished the increase of Bax/Bcl-2 ratio, which is a critical indicator of p53-mediated mitochondrial damage, in response to VPA. The nuclear factor (NF)-κB inhibitors, Bay 11-7082 and parthenolide, abolished the preventive action of LPS on VPA-induced apoptosis. A series of toll-like receptor ligands, Pam3CSK4, poly I:C, and CpG DNA as well as LPS prevented VPA-induced apoptosis. Taken together, LPS was suggested to prevent VPA-induced apoptosis via activation of anti-apoptotic NF-κB and inhibition of pro-apoptotic p53 activation. The detailed inhibitory mechanism of VPA-induced apoptosis by LPS is discussed.

Effects of tubeimoside-1 on the proliferation and apoptosis of BGC823 gastric cancer cells in vitro

Natural products isolated from Chinese medicinal herbs are useful sources of new drugs for cancer therapy. Tubeimoside-1 (TBMS1) is a natural compound isolated from the Chinese medicinal herb Bolbostemma paniculatum (Maxim.) Franquet (Cucurbitaceae). Studies have shown that TBMS1 has anticancer effects in various human cancer cell lines. However, the effect of TBMS1 on human gastric cancer cells is unknown. In the present study, it was observed that TBMS1 inhibited BGC823 gastric cancer cell proliferation in a concentration- and time-dependent manner. Fluorescent microscopy and flow cytometric analysis showed that TBMS1 induced BGC823 cell apoptosis in a concentration-dependent manner. Western blot analysis also showed that TBMS1 induced apoptosis by regulation of the Bcl-2 gene family in BGC823 cells. These findings indicate that TBMS1 may be developed as a possible therapeutic agent for the management of gastric cancer.

Synergistic effects of histone deacetylase inhibitor in combination with mTOR inhibitor in the treatment of prostate carcinoma

The aim of this study was to elucidate whether the treatment of a prostate carcinoma cell line (LNCaP) and LNCaP-derived tumors with the histone deacetylase (HDAC) inhibitor valproate in combination with the mammalian target of rapamycin (mTOR) inhibitor temsirolimus resulted in synergistic effects on cell proliferation and tumor growth. LNCaP cells were treated with valproate, temsirolimus or a combination of both. The proliferation rates and the expression of key markers of tumorigenesis were evaluated. In in vivo experiments, LNCaP cells were implanted into immune-suppressed male nude mice. Mice were treated with valproate (per os), temsirolimus (intravenously) or with a combination of both. Tumor volumes were calculated and mRNA expression was quantified. The incubation of LNCaP cells with the combination of valproate and temsirolimus resulted in a decrease of cell proliferation with an additive effect of both drugs in comparison to the single treatment. In particular, the combined application of valproate and temsirolimus led to a significant upregulation of insulin-like growth factor-binding protein-3 (IGFBP-3), which mediates apoptosis and inhibits tumor cell proliferation. In the mouse model, we found no significant differences in tumor growth between the different treatment arms but immunohistological analyses showed that tumors treated with a combination of valproate and temsirolimus, but not with the single drugs alone, exhibited a significant lower proliferation capacity.

Protocatechualdehyde possesses anti-cancer activity through downregulating cyclin D1 and HDAC2 in human colorectal cancer cells

Protocatechualdehyde (PCA) is a naturally occurring polyphenol found in barley, green cavendish bananas, and grapevine leaves. Although a few studies reported growth-inhibitory activity of PCA in breast and leukemia cancer cells, the underlying mechanisms are still poorly understood. Thus, we performed in vitro study to investigate if treatment of PCA affects cell proliferation and apoptosis in human colorectal cancer cells and define potential mechanisms by which PCA mediates growth arrest and apoptosis of cancer cells. Exposure of PCA to human colorectal cancer cells (HCT116 and SW480 cells) suppressed cell growth and induced apoptosis in dose-dependent manner. PCA decreased cyclin D1 expression in protein and mRNA level and suppressed luciferase activity of cyclin D1 promoter, indicating transcriptional downregulation of cyclin D1 gene by PCA. We also observed that PCA treatment attenuated enzyme activity of histone deacetylase (HDAC) and reduced expression of HDAC2, but not HDAC1. These findings suggest that cell growth inhibition and apoptosis by PCA may be a result of HDAC2-mediated cyclin D1 suppression.

HDAC inhibition delays cell cycle progression of human bladder cancer cells in vitro

Our aim was to analyze the impact of the histone deacetylase (HDAC)-inhibitor valproic acid (VPA) on bladder cancer cell growth in vitro. RT-4, TCCSUP, UMUC-3, and RT-112 bladder cancer cells were treated with VPA (0.125-1 mmol/l) without and with preincubation periods of 3 and 5 days. Controls remained untreated. Tumor cell growth, cell cycle progression, and cell cycle-regulating proteins were investigated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, flow cytometry, and western blotting, respectively. Effects of VPA on histone H3 and H4 acetylation and HDAC3 and HDAC4 were also determined. Without preincubation, no tumor cell growth reduction was observed with 0.125 and 0.25 mmol/l VPA in TCCSUP, UMUC-3, and RT-112 cells, whereas 0.5 and 1 mmol/l VPA diminished the cell number significantly. VPA (0.25 mmol/l) did exert tumor growth-blocking effects after a 3-day preincubation. To achieve antitumor effects with VPA (0.125 mmol/l), a 5-day preincubation was necessary. A 3-day or 5-day preincubation was also necessary to distinctly delay cell cycle progression, with maximum effects at VPA (1 mmol/l). After the 5-day preincubation, the cell cycle-regulating proteins cdk1, cdk2, cdk4, and cyclins B, D1, and E were reduced, whereas p27 was enhanced. Diminished HDAC3 and 4 expression induced by VPA was accompanied by elevated acetylation of H3 and H4. VPA exerted growth-blocking properties on a panel of bladder cancer cell lines, commensurate with dose and exposure time. Long-term application induced much stronger effects than did shorter application and should be considered when designing therapeutic strategies for treating bladder carcinoma.

Adiponectin receptor-1 expression is associated with good prognosis in gastric cancer

Background

Adiponectin is inversely related to BMI, positively correlates with insulin sensitivity, and has anti-atherogenic effects. In recent years, adiponectin has been well studied in the field of oncology. Adiponectin has been shown to have antiproliferative effects on gastric cancer, and adiponectin expression is inversely correlated with clinical staging of the disease. However, no studies have reported the correlation between serum adiponectin and receptor expression with disease progression.

Methods

In this study, we evaluated expression levels of 2 adiponectin receptors--AdipoR1 and AdipoR2--and attempted to correlate their expression with prognosis in gastric cancer patients. AdipoR1 and AdipoR2 expression in gastric cancer cell lines (MKN45, TMK-1, NUGC3, and NUGC4) was evaluated by western blotting analysis, and the antiproliferative potential of adiponectin was examined in vitro. Serum adiponectin levels were evaluated in 100 gastric cancer patients, and the expression of AdipoR1 and AdipoR2 was assessed by immunohistochemical staining.

Results

MKN45 and NUGC3 expressed higher levels of AdipoR1 compared to NUGC4, even though there was no significance in AdipoR2 expression. The antiproliferative effect of adiponectin was confirmed in MKN45 and NUGC3 at 10 μg/ml. No significant associations were observed between serum adiponectin levels and clinicopathological characteristics, but lymphatic metastasis and peritoneal dissemination were significantly higher in the negative AdipoR1 immunostaining group (24/32, p = 0.013 and 9/32, p = 0.042, respectively) compared to the positive AdipoR1 group (lymphatic metastasis, 33/68; peritoneal dissemination, 8/68). On the other hand, AdipoR2 expression was only associated with histopathological type (p = 0.001). In survival analysis, the AdipoR1 positive staining group had significantly longer survival rates than the negative staining group (p = 0.01). However, multivariate analysis indicated that AdipoR1 was not an independent prognostic factor on patient's survival on gastric cancer.

Conclusions

In gastric cancer, adiponectin has the possibility to be involved in cell growth suppression via AdipoR1. The presence of AdipoR1 could be a novel anticancer therapeutic target in gastric cancer.

Down-regulation of UHRF1, associated with re-expression of tumor suppressor genes, is a common feature of natural compounds exhibiting anti-cancer properties

Over-expressed in numerous cancers, Ubiquitin-like containing PHD Ring Finger 1 (UHRF1, also known as ICBP90 or Np95) is characterized by a SRA domain (Set and Ring Associated) which is found only in the UHRF family. UHRF1 constitutes a complex with histone deacetylase 1 (HDAC1) and DNA methyltransferase 1 (DNMT1) via its SRA domain and represses the expression of several tumour suppressor genes (TSGs) including p16INK4A, hMLH1, BRCA1 and RB1. Conversely, UHRF1 is regulated by other TSGs such as p53 and p73. UHRF1 is hypothetically involved in a macro-molecular protein complex called "ECREM" for "Epigenetic Code Replication Machinery". This complex would be able to duplicate the epigenetic code by acting at the DNA replication fork and by activating the right enzymatic activity at the right moment. There are increasing evidence that UHRF1 is the conductor of this replication process by ensuring the crosstalk between DNA methylation and histone modifications via the SRA and Tandem Tudor Domains, respectively. This cross-talk allows cancer cells to maintain the repression of TSGs during cell proliferation. Several studies showed that down-regulation of UHRF1 expression in cancer cells by natural pharmacological active compounds, favors enhanced expression or re-expression of TSGs, suppresses cell growth and induces apoptosis. This suggests that hindering UHRF1 to exert its role in the duplication of the methylation patterns (DNA + histones) is responsible for inducing apoptosis. In this review, we present UHRF1 expression as a target of several natural products and we discuss their underlying molecular mechanisms and benefits for chemoprevention and chemotherapy.