A synthetic compound, 1,5-bis(2-methoxyphenyl)penta-1,4-dien-3-one (B63), induces apoptosis and activates endoplasmic reticulum stress in non-small cell lung cancer cells

Design, synthesis, and evaluation of cyclic C7-bridged monocarbonyl curcumin analogs containing an o-methoxy phenyl group as potential agents against gastric cancer

The structure-activity relationship (SAR) between toxicity and the types of linking ketones of C7 bridged monocarbonyl curcumin analogs (MCAs) was not clear yet. In the pursuit of effective and less cytotoxic chemotherapeutics, we conducted a SAR analysis using various diketene skeletons of C7-bridged MCAs, synthesized cyclic C7-bridged MCAs containing the identified low-toxicity cyclopentanone scaffold and an o-methoxy phenyl group, and assessed their anti-gastric cancer activity and safety profile. Most compounds exhibited potent cytotoxic activities against gastric cancer cells. We developed a quantitative structure-activity relationship model (R2 > 0.82) by random Forest method, providing important information for optimizing structure. An optimized compound 2 exhibited in vitro and in vivo anti-gastric cancer activity partly through inhibiting the AKT and STAT3 pathways, and displayed a favorable in vivo safety profile. In summary, this paper provided a promising class of MCAs and a potential compound for the development of chemotherapeutic drugs.

Natural products for gastric carcinoma prevention and treatment: Focus on their antioxidant stress actions in the Correa's cascade

BACKGROUND

Correa's cascade is a pathological process beginning from gastritis to gastric precancerous lesions, and finally to gastric carcinoma (GC). While the pathogenesis of GC remains unclear, oxidative stress plays a prominent role throughout the entire Correa's cascade process. Studies have shown that some natural products (NPs) could halt and even reverse the development of the Correa's cascade by targeting oxidative stress.

METHODS

To review the effects and mechanism by which NPs inhibit the Correa's cascade through targeting oxidative stress, data were collected from PubMed, Embase, Web of Science, ScienceDirect, and China National Knowledge Infrastructure databases from initial establishment to April 2023. NPs were classified and summarized by their mechanisms of action.

RESULTS

NPs, such as terpenoid, polyphenols and alkaloids, exert multistep antioxidant stress effects on the Correa's cascade. These effects include preventing gastric mucosal inflammation (stage 1), reversing gastric precancerous lesions (stage 2), and inhibiting gastric carcinoma (stage 3). NPs can directly impact the conversion of gastritis to GC by targeting oxidative stress and modulating signaling pathways involving IL-8, Nrf2, TNF-α, NF-κB, and ROS/MAPK. Among which polyphenols have been studied more and are of high research value.

CONCLUSIONS

NPs display a beneficial multi-step action on the Correa's cascade, and have potential value for clinical application in the prevention and treatment of gastric cancer by regulating the level of oxidative stress.

An Update on Potential Molecular Biomarkers of Dietary Phytochemicals Targeting Lung Cancer Interception and Prevention

Since ancient times, dietary phytochemicals are known for their medicinal properties. They are broadly classified into polyphenols, terpenoids, alkaloids, phytosterols, and organosulfur compounds. Currently, there is considerable interest in their potential health effects against various diseases, including lung cancer. Lung cancer is the leading cause of cancer deaths with an average of five-year survival rate of lung cancer patients limited to just 14%. Identifying potential early molecular biomarkers of pre-malignant lung cancer cells may provide a strong basis to develop early cancer detection and interception methods. In this review, we will discuss molecular changes, including genetic alterations, inflammation, signal transduction pathways, redox imbalance, epigenetic and proteomic signatures associated with initiation and progression of lung carcinoma. We will also highlight molecular targets of phytochemicals during lung cancer development. These targets mainly consist of cellular signaling pathways, epigenetic regulators and metabolic reprogramming. With growing interest in natural products research, translation of these compounds into new cancer prevention approaches to medical care will be urgently needed. In this context, we will also discuss the overall pharmacokinetic challenges of phytochemicals in translating to humans. Lastly, we will discuss clinical trials of phytochemicals in lung cancer patients.

Curcumin and Its Analogs in Non-Small Cell Lung Cancer Treatment: Challenges and Expectations

Researchers have made crucial advances in understanding the pathogenesis and therapeutics of non-small cell lung cancer (NSCLC), improving our understanding of lung tumor biology and progression. Although the survival of NSCLC patients has improved due to chemoradiotherapy, targeted therapy, and immunotherapy, overall NSCLC recovery and survival rates remain low. Thus, there is an urgent need for the continued development of novel NSCLC drugs or combination therapies with less toxicity. Although the anticancer effectiveness of curcumin (Cur) and some Cur analogs has been reported in many studies, the results of clinical trials have been inconsistent. Therefore, in this review, we collected the latest related reports about the anti-NSCLC mechanisms of Cur, its analogs, and Cur in combination with other chemotherapeutic agents via the Pubmed database (accessed on 18 June 2022). Furthermore, we speculated on the interplay of Cur and various molecular targets relevant to NSCLC with discovery studio and collected clinical trials of Cur against NSCLC to clarify the role of Cur and its analogs in NSCLC treatment. Despite their challenges, Cur/Cur analogs may serve as promising therapeutic agents or adjuvants for lung carcinoma treatment.

Therapeutic potentials of curcumin in the treatment of non-small-cell lung carcinoma

Non-small-cell lung carcinoma (NSCLC) is one of the most lethal malignancies that include more than 80% of lung cancer cases worldwide. During the past decades, plants and plant-derived products have attracted great interest in the treatment of various human diseases. Curcumin, the turmeric isolated natural phenolic compound, has shown a promising chemo-preventive and anticancer agent. Numerous studies have shown that curcumin delays the initiation and progression of NSCLC by affecting a wide range of molecular targets and cell signalling pathways including NF-kB, Akt, MAPKS, BCL-2, ROS and microRNAs (miRNAs). However, the poor oral bioavailability and low chemical stability of curcumin remain as major challenges in the utilisation of this compound as a therapeutic agent. Different analogs of curcumin and new delivery systems (e.g., micelles, nanoparticles and liposomes) provided promising solutions to overcome these obstacles and improve curcumin pharmacokinetic profile. The present review focuses on current reported studies about anti-NSCLC effects of curcumin. NSCLC involved miRNAs whose expression is regulated by curcumin has also been discussed. Furthermore, recent researches on the use of curcumin analogs and delivery systems to enhance the curcumin benefits in NSCLC are also described.

Curcuminoid B63 induces ROS-mediated paraptosis-like cell death by targeting TrxR1 in gastric cells

Gastric cancer is one of the leading causes of cancer-related deaths. Chemotherapy has improved long-term survival of patients with gastric cancer. Unfortunately, cancer readily develops resistance to apoptosis-inducing agents. New mechanisms, inducing caspase-independent paraptosis-like cell death in cancer cells is presently emerging as a potential direction. We previously developed a curcumin analog B63 as an anti-cancer agent in pre-clinical evaluation. In the present study, we evaluated the effect and mechanism of B63 on gastric cancer cells. Our studies show that B63 targets TrxR1 protein and increases cellular reactive oxygen species (ROS) level, which results in halting gastric cancer cells and inducing caspase-independent paraptotic modes of death. The paraptosis induced by B63 was mediated by ROS-mediated ER stress and MAPK activation. Either overexpression of TrxR1 or suppression of ROS normalized B63-induced paraptosis in gastric cancer cells. Furthermore, B63 caused paraptosis in 5-fluorouracil-resistant gastric cancer cells, and B63 treatment reduced the growth of gastric cancer xenografts, which was associated with increased ROS and paraptosis. Collectively, our findings provide a novel strategy for the treatment of gastric cancer by utilizing TrxR1-mediated oxidative stress generation and subsequent cell paraptosis.

Flaxseed Lignans Enhance the Cytotoxicity of Chemotherapeutic Agents against Breast Cancer Cell Lines MDA-MB-231 and SKBR3

Systemic cytotoxic chemotherapy remains the mainstay of metastatic breast cancer; however, prognosis and overall survival is unfavorable due to inadequate treatment response and/or unacceptable toxicity. Natural compounds and their active metabolites receive increasing attention as possible adjuvant therapy with cancer chemotherapeutics to improve treatment response, survival rates, and quality of life of breast cancer patients. This study investigated the combination of flaxseed lignans (Secoisolariciresinol and Enterolactone) with classic chemotherapeutic agents (Docetaxel, Doxorubicin, and Carboplatin) with different mechanisms of action to determine whether flaxseed lignans could enhance the cytotoxic effect of such drugs in the metastatic breast cancer cell lines, SKBR3 and MDA-MB-231. The experimental data suggests that flaxseed lignans significantly enhanced the ability of chemotherapeutic agents to cause cytotoxicity in SKBR3 and MDA-MB-231 breast cancer cells. A three compound combination study found that enterolactone and metformin together in combination with relatively low concentrations of chemotherapeutic drugs were able to significantly decrease cancer cell viability, compared to low concentrations of the individual chemotherapeutic drug alone. Our in vitro evaluation suggests a future direction in improving chemotherapeutic efficacy in breast cancer by adjuvant therapy with the flaxseed lignans.

Increased Intracellular Reactive Oxygen Species Mediates the Anti-Cancer Effects of WZ35 via Activating Mitochondrial Apoptosis Pathway in Prostate Cancer Cells

BACKGROUND

The limited treatment option for recurrent prostate cancer and eventual resistant to conventional chemotherapy drugs has fueled continued interest in finding new anti-neoplastic agents. WZ35, a chemical analog of curcumin, had been demonstrated to have high chemical stability and potential anticancer effects in gastric cancer cells. The present study aimed to investigate the anti-prostate cancer effects of WZ35 in vitro and in vivo as well as the underlying mechanism.

METHODS

Two prostate cancer cell lines RM-1 and DU145 were utilized to test the anti-cancer effects of WZ35 and the underlying mechanism. MTT assay was used to assess the cytotoxic effect of WZ35. Cell cycle distribution, apoptosis, alteration of ROS, and [Ca²⁺ ]_i level were evaluated using flow cytometry. Western blotting assay was applied to measure the levels of proteins associated with apoptosis and cell cycle. Immunofluorescence staining and Electron micrographs were used to evaluate activation of mitochondrial apoptosis pathway. Tumor models in nude mice were induced by injection of RM-1 prostate cancer cells to test the in vivo anticancer action of WZ35.

RESULTS

Our results showed that WZ35 treatment induced loss of cell viability, cell apoptosis, and G2/M cycle arrest in both RM-1 and DU145 cells, coupled with ROS overproduction, intracellular calcium surge, and activation of mitochondrial apoptosis pathway in RM-1 cells. Interestingly, all above changes induced by WZ35 were completely reversed by ROS blockage. In addition, prevention of [Ca²⁺ ]_i elevation by BAPTA/AM also inhibited activation of mitochondrial apoptosis pathway induced by WZ35. In vivo studies, WZ35 treatment significantly inhibited RM-1 homograft tumor growth along with increased ROS accumulation, mitochondrial disruption, and cell apoptosis in tumor tissues.

CONCLUSIONS

In conclusion, this work provides a novel anticancer candidate for the treatment of prostate cancer and demonstrated that increased ROS mediate the anti-cancer effects of WZ35 via activating mitochondrial apoptosis pathway. Importantly, this work also reveals that targeting ROS generation might be an effective strategy in human androgen-resistant prostate cancer treatment. Prostate 77:489-504, 2017. © 2016 Wiley Periodicals, Inc.

A novel curcumin analog binds to and activates TFEB in vitro and in vivo independent of MTOR inhibition

Autophagy dysfunction is a common feature in neurodegenerative disorders characterized by accumulation of toxic protein aggregates. Increasing evidence has demonstrated that activation of TFEB (transcription factor EB), a master regulator of autophagy and lysosomal biogenesis, can ameliorate neurotoxicity and rescue neurodegeneration in animal models. Currently known TFEB activators are mainly inhibitors of MTOR (mechanistic target of rapamycin [serine/threonine kinase]), which, as a master regulator of cell growth and metabolism, is involved in a wide range of biological functions. Thus, the identification of TFEB modulators acting without inhibiting the MTOR pathway would be preferred and probably less deleterious to cells. In this study, a synthesized curcumin derivative termed C1 is identified as a novel MTOR-independent activator of TFEB. Compound C1 specifically binds to TFEB at the N terminus and promotes TFEB nuclear translocation without inhibiting MTOR activity. By activating TFEB, C1 enhances autophagy and lysosome biogenesis in vitro and in vivo. Collectively, compound C1 is an orally effective activator of TFEB and is a potential therapeutic agent for the treatment of neurodegenerative diseases.

A novel curcuminoid exhibits enhanced antitumor activity in nasopharyngeal carcinoma

Curcumin shows growth-inhibition against tumor cells through multi-target mechanisms. Nevertheless, the poor stability and pharmacokinetics considerably limit its clinical functions. Increased effort has been put into the chemical alteration of curcumin to find potential analogues with improved bioavailability and antitumor activities. In this study, the antitumor activity of a novel curcuminoid (B63) in nasopharyngeal carcinoma (NPC) was examined. The MTT and colony formation assays were used to detect NPC cell viability and proliferation. Flow cytometry was used to detect cell cycle distribution. The Annexin V/PI staining assay and cleavage PARP and cleavage caspase-3 expression were used to examine apoptosis. Western blotting was used to examine the protein expression of endoplasmic reticulum (ER) stress pathway markers, XBP-1, ATF-4 and CHOP. The suppressive effect of B63 on tumor growth was examined in vivo by subcutaneously inoculated NPC in a tumor model using nude mice. Treatment with B63 potentially caused growth inhibition and apoptosis in NPC cells in a dose- and time-responsive manner. Its antitumor effect was associated with the ER stress activation. Nevertheless, the same dose of curcumin did not activate ER stress. In addition, knockdown of Chop attenuated B63-induced cell viability inhibition, suggesting that the apoptotic pathway is ER stress-dependent. The tumor volume and weight were significantly reduced by pretreating the NPC cells with B63 before implantation in the in vivo mouse model. B63 exhibited a more potent antitumor action than curcumin in NPC. These observations on the novel compound B63 indicate a novel candidate for NPC therapy.

Da0324, an inhibitor of nuclear factor-κB activation, demonstrates selective antitumor activity on human gastric cancer cells

Background

The transcription factor nuclear factor-κB (NF-κB) is constitutively activated in a variety of human cancers, including gastric cancer. NF-κB inhibitors that selectively kill cancer cells are urgently needed for cancer treatment. Curcumin is a potent inhibitor of NF-κB activation. Unfortunately, the therapeutic potential of curcumin is limited by its relatively low potency and poor cellular bioavailability. In this study, we presented a novel NF-κB inhibitor named Da0324, a synthetic asymmetric mono-carbonyl analog of curcumin. The purpose of this study is to research the expression of NF-κB in gastric cancer and the antitumor activity and mechanism of Da0324 on human gastric cancer cells.

Methods

The expressions between gastric cancer tissues/cells and normal gastric tissues/cells of NF-κB were evaluated by Western blot. The inhibition viability of compounds on human gastric cancer cell lines SGC-7901, BGC-823, MGC-803, and normal gastric mucosa epithelial cell line GES-1 was assessed with the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay. Absorption spectrum method and high-performance liquid chromatography method detected the stability of the compound in vitro. The compound-induced changes of inducible NF-κB activation in the SGC-7901 and BGC-823 cells were examined by Western blot analysis and immunofluorescence methods. The antitumor activity of compound was performed by clonogenic assay, matrigel invasion assay, flow cytometric analysis, Western blot analysis, and Hoechst 33258 staining assay.

Results

High levels of p65 were found in gastric cancer tissues and cells. Da0324 displayed higher growth inhibition against several types of gastric cancer cell lines and showed relatively low toxicity to GES-1. Moreover, Da0324 was more stable than curcumin in vitro. Western blot analysis and immunofluorescence methods showed that Da0324 blocked NF-κB activation. In addition, Da0324 significantly inhibited tumor proliferation and invasion, arrested the cell cycle, and induced apoptosis in vitro.

Conclusion

The asymmetric mono-carbonyl analog of curcumin Da0324 exhibited significantly improved antigastric cancer activity. Da0324 may be a promising NF-κB inhibitor for the selective targeting of cancer cells. However, further studies are needed in animals to validate these findings for the therapeutic use of Da0324.

Curcumin analog WZ35 induced cell death via ROS-dependent ER stress and G2/M cell cycle arrest in human prostate cancer cells

Background

Prostate cancer is the most commonly diagnosed malignancy among men. The Discovery of new agents for the treatment of prostate cancer is urgently needed. Compound WZ35, a novel analog of the natural product curcumin, exhibited good anti-prostate cancer activity, with an IC₅₀ of 2.2 μM in PC-3 cells. However, the underlying mechanism of WZ35 against prostate cancer cells is still unclear.

Methods

Human prostate cancer PC-3 cells and DU145 cells were treated with WZ35 for further proliferation, apoptosis, cell cycle, and mechanism analyses. NAC and CHOP siRNA were used to validate the role of ROS and ER stress, respectively, in the anti-cancer actions of WZ35.

Results

Our results show that WZ35 exhibited much higher cell growth inhibition than curcumin by inducing ER stress-dependent cell apoptosis in human prostate cells. The reduction of CHOP expression by siRNA partially abrogated WZ35-induced cell apoptosis. WZ35 also dose-dependently induced cell cycle arrest in the G2/M phase. Furthermore, we found that WZ35 treatment for 30 min significantly induced reactive oxygen species (ROS) production in PC-3 cells. Co-treatment with the ROS scavenger NAC completely abrogated the induction of WZ35 on cell apoptosis, ER stress activation, and cell cycle arrest, indicating an upstream role of ROS generation in mediating the anti-cancer effect of WZ35.

Conclusions

Taken together, this work presents the novel anticancer candidate WZ35 for the treatment of prostate cancer, and importantly, reveals that increased ROS generation might be an effective strategy in human prostate cancer treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1851-3) contains supplementary material, which is available to authorized users.

Identification of regulators of the early stage of viral hemorrhagic septicemia virus infection during curcumin treatment

The effect of curcumin pretreatment (15-240 μM) in fathead minnow cells infected with viral hemorrhagic septicemia virus (VHSV) was evaluated. Cell viability, apoptosis and viral copy number were analyzed using Cell Counting Kit-8 assay, Annexin V staining, and reverse transcription-PCR, respectively. Pretreatment with 120 μM curcumin showed an increase in viability (>90% of mock) of VHSV-infected cells and reduction in the copy number (0.2-log reduction in VHSV N gene expression), reactive oxygen species and apoptosis in the cells without cytotoxic effects. To understand the mechanisms underlaying the antiviral effects of curcumin pretreatment, a comparative proteomic analysis was performed in four samples (M, mock; C, curcumin-treated; V, VHSV-infected; and CV, curcumin-treated VHSV-infected) in triplicate. In total, 185 proteins were detected. The analysis showed that three proteins, including heat shock cognate 71 (HSC71), actin, alpha cardiac muscle (ACTC1) and elongation factor 1 (EEF1) were differentially expressed between V and CV samples. Network analysis performed by Ingenuity Pathways Analysis (IPA) showed that HSC71 was the primary protein interacting with fibronectin (FN) 1, actins (ACTB, ACTG, F-actin) and gelsolin (GSN) in both V and CV samples and thus is a strong target candidate for the protection from VHSV infection at the viral entry stage. Our proteomics data suggest that curcumin pretreatment inhibits entry of VHSV in cells by downregulating FN1 or upregulating F-actin. For both proteins, HSC71 acts as a binding protein that modulates their functions. Furthermore, consistent with the effect of a heat shock protein inhibitor (KNK437), curcumin downregulated HSC71 expression with increasing viability of VHSV-infected cells and inhibited VHSV replication, suggesting that the downregulation of HSC71 could be responsible for the antiviral activity of curcumin. In conclusion, this study indicates that the suppression of viral entry by rearrangement of the F-actin/G-actin ratio via downregulating HSC71 is a plausible mechanism by which curcumin pretreatment controls the early stages of VHSV infection.

Eliminating the heart from the curcumin molecule: monocarbonyl curcumin mimics (MACs)

Curcumin is a natural product with several thousand years of heritage. Its traditional Asian application to human ailments has been subjected in recent decades to worldwide pharmacological, biochemical and clinical investigations. Curcumin’s Achilles heel lies in its poor aqueous solubility and rapid degradation at pH ~ 7.4. Researchers have sought to unlock curcumin’s assets by chemical manipulation. One class of molecules under scrutiny are the monocarbonyl analogs of curcumin (MACs). A thousand plus such agents have been created and tested primarily against cancer and inflammation. The outcome is clear. In vitro, MACs furnish a 10–20 fold potency gain vs. curcumin for numerous cancer cell lines and cellular proteins. Similarly, MACs have successfully demonstrated better pharmacokinetic (PK) profiles in mice and greater tumor regression in cancer xenografts in vivo than curcumin. The compounds reveal limited toxicity as measured by murine weight gain and histopathological assessment. To our knowledge, MAC members have not yet been monitored in larger animals or humans. However, Phase 1 clinical trials are certainly on the horizon. The present review focuses on the large and evolving body of work in cancer and inflammation, but also covers MAC structural diversity and early discovery for treatment of bacteria, tuberculosis, Alzheimer’s disease and malaria.

A monocarbonyl analogue of curcumin, 1,5-bis(3-hydroxyphenyl)-1,4-pentadiene-3-one (Ca 37), exhibits potent growth suppressive activity and enhances the inhibitory effect of curcumin on human prostate cancer cells

Prostate carcinoma is one of the leading causes of cancer-related morbidity and mortality in males in western countries. Curcumin exhibits growth-suppressive activity against several cancers, including prostate cancer, but it has poor bioavailability. The purpose of this study was to evaluate the anticancer potency and mechanism of a curcumin analogue, 1,5-bis(3-hydroxyphenyl)-1,4-pentadiene-3-one (Ca 37), in human prostate cancer. Studies were performed in established human prostate cancer cell lines (PC-3 and DU145) as well as in a murine xenograft tumor (PC-3) model. Ca 37 presented a preferential suppression capacity against growth and migration toward prostate cancer cells compared with curcumin. Ca 37 impaired the bioenergetics system, promoted cell cycle arrest and apoptosis activation in PC-3 cells. In addition, 0.5 μmol (6.65 mg/kg body weight) of Ca 37 significantly inhibited the growth of the prostate xenografted tumors, whereas 6 μmol (110 mg/kg body weight) of curcumin had little effect. Furthermore, a combination of Ca 37 and curcumin resulted in enhanced antitumor activity in prostate cancer cells. N-Acetylcysteine abrogated both reactive oxygen species (ROS) production and viability loss induced by Ca 37 but partially prevented growth inhibition in PC-3 cells treated with curcumin alone, or a combination with Ca 37. The data indicate that induction of ROS plays a vital role in the growth inhibitory effect of Ca 37 in PC-3 cells. This study suggests that Ca 37, alone or in combination with curcumin, may be a promising anticancer agent for prostate cancer therapy.

Novel curcumin analogue IHCH exhibits potent anti‑proliferative effects by inducing autophagy in A549 lung cancer cells

Curcumin is a natural polyphenolic compound that exhibits strong antioxidant and anticancer activities; however, low bioavailability has restricted its application in chemotherapeutic trials. The present study aimed to investigate the anticancer effect of the novel curcumin derivative 2E,6E‑2‑(1H‑indol‑3‑yl) methylene)‑6‑(4‑hydroxy‑3‑methoxy benzylidene)‑cyclohexanone (IHCH) on A549 lung cancer cells. Cells were treated with IHCH at different concentrations (1‑40 µM) for different time periods (1‑36 h). Microscopic analysis revealed that IHCH inhibited A549 cell growth and induced the formation of characteristic autophagolysosomes in a dose‑ and time‑dependent manner. Furthermore, the inhibitory rate of IHCH (40 µM) on A549 cell viability was 77.34% after 36 h of treatment. Acridine orange staining revealed an increase in autophagic vacuoles in the IHCH‑treated A549 cells. Monodansylcadaverine staining was used to analyze autophagy rate. Immunocytochemistry revealed an increase in light chain (LC) 3 protein expression in the IHCH‑treated cells and western blot analysis detected the conversion of LC3‑I to LC3‑II, as well as the recruitment of LC3 to autophagosomes in the cytoplasmatic compartment, suggesting the occurrence of autophagy. These findings show that IHCH induced autophagy in A549 cells, which is a novel cell death mechanism induced by curcumin derivatives.

A synthetic curcumin derivative hydrazinobenzoylcurcumin induces autophagy in A549 lung cancer cells

CONTEXT

Curcumin exhibits growth-suppressive activity against a variety of cancer cells, but low bioavailability restricts its application in chemotherapeutic trials. Nowadays, a growing number of curcumin derivatives or analogs are known, hoping to replace curcumin and circumvent this problem. Hydrazinobenzoylcurcumin (HBC) has been synthesized and identified as a potent inhibitor of cell proliferation in previous reports.

OBJECTIVE

This study presents a novel mechanism of cell autophagy induced by HBC in the human non-small lung epithelial carcinoma (A549) cells.

MATERIALS AND METHODS

Cells were cultured and treated with HBC at different concentrations (10-80 μM) and at different time periods (1-24 h). Microscopic analysis was used to detect the morphology changes and autophagolysosomes of A549 cells. An acridine orange staining assay was conducted to evaluate the autophagolysosomes and autophagic vacuoles was analyzed by monodansylcadaverine (MDC) and GFP-LC3 transfection analysis. Western blotting was used to assess the conversion of microtubule-associated protein light chain 3 (LC3).

RESULTS

HBC could induce A549 cells autophagolysosomes formation in a dose and time-dependent manner and the inhibitory rate of HBC (80 μM) on the viability of A549 cells reached 76.68 ± 5.81% after 24 h of treatment. Autophagic vacuoles increased in a concentration-dependent manner in HBC-treated cell. Furthermore, conversion of LC3-I to LC3-II, accumulation of GFP-tagged LC3 positive intracellular vacuoles and increased fusion of autophagosomes with lysosomes suggested the occurrence of autophagy.

CONCLUSION

Our data indicate that HBC induced A549 cell autophagy, which is a novel cell death mechanism induced by curcumin derivatives.

An oxygen-chelate complex, palladium bis-acetylacetonate, induces apoptosis in H460 cells via endoplasmic reticulum stress pathway rather than interacting with DNA

Current precious-metal-containing anticancer agents are mostly chelated with N-containing ligands and function by interacting with DNA. In the present study, Pd(acac)2, a Pd(II) complex containing four O-donor ligands, has been evaluated as an active anticancer agent. Pd(acac)2 showed no interaction with N-ligand-containing DNA and the S-ligand-containing DMSO, probably because of the two six-member chelate rings that limit the release of the central Pd nuclei to bind to other ligands. Importantly, we found that Pd(acac)2 exhibited better growth inhibitory effects than cisplatin in several cancer cells. Treatment with Pd(acac)2 significantly induced apoptosis in H460 cells. Mechanistically, Pd(acac)2 induced the activation of a series of key components in ER stress-mediated apoptotic pathway, followed by caspase cleavage and activation, while cisplatin showed no similar effects. CHOP knockdown by specific siRNA significantly attenuated Pd(acac)2-induced cell apoptosis. Finally, Pd(acac)2 significantly inhibits H460 cell growth in xenograft mouse models. Taken together, these mechanistic insights on Pd(acac)2 provide us with a novel mechanism and strategy for the development of precious-metal-based anticancer drugs.

B19, a novel monocarbonyl analogue of curcumin, induces human ovarian cancer cell apoptosis via activation of endoplasmic reticulum stress and the autophagy signaling pathway

BACKGROUND

The unfolded protein response, autophagy and endoplasmic reticulum (ER) stress-induced apoptosis regulate tumor cell fate and have become novel signaling targets for the development of cancer therapeutic drugs. Curcumin has been used to treat several different cancers, including ovarian cancer, in clinical trials and research; however, the role of ER stress and autophagy in the therapeutic effects of curcumin and new curcumin analogues remains unclear.

METHODS

Cell viability was determined using the MTT assay. Apoptosis was detected using flow cytometry with PI/Annexin V-FITC staining. The expression levels of ER stress- and autophagy-related proteins were analyzed by western blotting. The activation of autophagy was detected using immunofluorescence staining.

RESULTS

We demonstrated that B19 induced HO8910 cell apoptosis in a dose-responsive manner. We also determined and that this effect was associated with corresponding increases in a series of key components in the UPR and ER stress-mediated apoptosis pathways, followed by caspase 3 cleavage and activation. We also observed that B19 treatment induced autophagy in HO8910 cells. The inhibition of autophagy using 3-methyladenine (3-MA) increased levels of intracellular misfolded proteins, which enhanced ovarian cancer apoptosis.

CONCLUSIONS

Our data indicate that ER stress and autophagy may play a role in the apoptosis that is induced by the curcumin analogue B19 in an epithelial ovarian cancer cell line and that autophagy inhibition can increase curcumin analogue-induced apoptosis by inducing severe ER stress.

Curcuma Contra Cancer? Curcumin and Hodgkin's Lymphoma

Curcumin, a phytochemical isolated from curcuma plants which are used as coloring ingredient for the preparation of curry powder, has several activities which suggest that it might be an interesting drug for the treatment or prevention of cancer. Curcumin targets different pathways which are involved in the malignant phenotype of tumor cells, including the nuclear factor kappa B (NFKB) pathway. This pathway is deregulated in multiple tumor entities, including Hodgkin’s lymphoma (HL). Indeed, curcumin can inhibit growth of HL cell lines and increases the sensitivity of these cells for cisplatin. In this review we summarize curcumin activities with special focus on possible activities against HL cells.