Apoptosis induced by genipin in human leukemia K562 cells: involvement of c-Jun N-terminal kinase in G₂/M arrest

Genipin's potential as an anti-cancer agent: from phytochemical origins to clinical prospects

This comprehensive review delves into the multifaceted aspects of genipin, a bioactive compound derived from medicinal plants, focusing on its anti-cancer potential. The review begins by detailing the sources and phytochemical properties of genipin, underscoring its significance in traditional medicine and its transition into contemporary cancer research. It then explores the intricate relationship between genipin's chemical structure and its observed anti-cancer activity, highlighting the molecular underpinnings contributing to its therapeutic potential. This is complemented by a thorough analysis of preclinical studies, which investigates genipin's efficacy against various cancer cell lines and its mechanisms of action at the cellular level. A crucial component of the review is the examination of genipin's bioavailability and pharmacokinetics, providing insights into how the compound is absorbed, distributed, metabolized, and excreted in the body. Then, this review offers a general and updated overview of the anti-cancer studies of genipin and its derivatives based on its basic molecular mechanisms, induction of apoptosis, inhibition of cell proliferation, and disruption of cancer cell signaling pathways. We include information that complements the genipin study, such as toxicity data, and we differentiate this review by including commercial status, disposition, and regulation. Also, this review of genipin stands out for incorporating information on proposals for a technological approach through its load in nanotechnology to improve its bioavailability. The culmination of this information positions genipin as a promising candidate for developing novel anti-cancer drugs capable of supplementing or enhancing current cancer therapies.

Genipin, a natural blue colorant precursor: Source, extraction, properties, and applications

Natural cross-linkers are extensively employed due to their low toxicity and biocompatibility benefits. Genipin acts as a precursor for producing blue colorants. The formation of these colorants involves the cross-linking reaction between genipin and primary amines present in amino acids, peptides, and proteins. Genipin is extracted from Gardenia jasminoides and Genipa americana. This article explains the cross-linking mechanism of genipin with proteins/polysaccharides to provide an overall understanding of its properties. Furthermore, it explores new sources of genipin and innovative methodologies to make the genipin recovery process efficient. Genipin increases food products' texture, gel strength, stability, and shelf life. The antibacterial, anti-inflammatory, and antioxidant properties of chitosan, gelatin, alginate, and hyaluronic acid increased after genipin cross-linking. Lastly, drawbacks, toxicity, and directions regarding the genipin cross-linking have also been addressed. The review article covers how to recover and cross-link genipin with biopolymers for industrial applications.

Ligand-Based Drug Design of Genipin Derivatives with Cytotoxic Activity against HeLa Cell Line: A Structural and Theoretical Study

Cervical cancer is a malignant neoplastic disease, mainly associated to HPV infection, with high mortality rates. Among natural products, iridoids have shown different biological activities, including cytotoxic and antitumor effects, in different cancer cell types. Geniposide and its aglycone Genipin have been assessed against different types of cancer. In this work, both iridoids were evaluated against HeLa and three different cervical cancer cell lines. Furthermore, we performed a SAR analysis incorporating 13 iridoids with a high structural similarity to Geniposide and Genipin, also tested in the HeLa cell line and at the same treatment time. Derived from this analysis, we found that the dipole moment (magnitude and direction) is key for their cytotoxic activity in the HeLa cell line. Then, we proceeded to the ligand-based design of new Genipin derivatives through a QSAR model (R2 = 87.95 and Q2 = 62.33) that incorporates different quantum mechanic molecular descriptor types (ρ, ΔPSA, ∆Polarizability2, and logS). Derived from the ligand-based design, we observed that the presence of an aldehyde or a hydroxymethyl in C4, hydroxyls in C1, C6, and C8, and the lack of the double bond in C7-C8 increased the predicted biological activity of the iridoids. Finally, ten simple iridoids (D9, D107, D35, D36, D55, D56, D58, D60, D61, and D62) are proposed as potential cytotoxic agents against the HeLa cell line based on their predicted IC50 value and electrostatic features.

UCP2 as a Cancer Target through Energy Metabolism and Oxidative Stress Control

Despite numerous therapies, cancer remains one of the leading causes of death worldwide due to the lack of markers for early detection and response to treatment in many patients. Technological advances in tumor screening and renewed interest in energy metabolism have allowed us to identify new cellular players in order to develop personalized treatments. Among the metabolic actors, the mitochondrial transporter uncoupling protein 2 (UCP2), whose expression is increased in many cancers, has been identified as an interesting target in tumor metabolic reprogramming. Over the past decade, a better understanding of its biochemical and physiological functions has established a role for UCP2 in (1) protecting cells from oxidative stress, (2) regulating tumor progression through changes in glycolytic, oxidative and calcium metabolism, and (3) increasing antitumor immunity in the tumor microenvironment to limit cancer development. With these pleiotropic roles, UCP2 can be considered as a potential tumor biomarker that may be interesting to target positively or negatively, depending on the type, metabolic status and stage of tumors, in combination with conventional chemotherapy or immunotherapy to control tumor development and increase response to treatment. This review provides an overview of the latest published science linking mitochondrial UCP2 activity to the tumor context.

Genipin, an Inhibitor of UCP2 as a Promising New Anticancer Agent: A Review of the Literature

Genipin is a protein cross-linking agent extracted from Gardenia (Gardenia jasminoides Ellis) fruits. This fruit has conventionally been used as a Chinese herbal medicine for the treatment of inflammation and jaundice and as an edible colorant in oriental countries. Uncoupling protein (UCP)-2 is a member of the family of uncoupling proteins, which are anion transporters positioned in the mitochondrial inner membrane. Genipin has been shown to have hepatoprotective activity, acting as an effective antioxidant and inhibitor of mitochondrial UCP2, and is also reported to exert significant anticancer effects. In this review, the author presents the latest progress of genipin as an anticancer agent and concisely describes its various mechanisms of action. In brief, genipin inhibits UCP2 to attenuate generation of reactive oxygen species (ROS), leading to ROS/c-Jun N-terminal kinase-dependent apoptosis of cancer cells. Genipin also increases the tissue inhibitors of matrix metalloproteases (MMP)-2, a kind of tumor promoter in a variety of cancers, as well as induces caspase-dependent apoptosis in in vitro and in vivo models. These findings suggest that genipin can serve as a promising novel antitumor agent that could be applicable for chemotherapy and/or chemoprevention for cancers.

Methods for crosslinking and stabilization of chitosan structures for potential medical applications

Chitosan is a well-known polymer widely used in tissue engineering and regenerative medicine. It is biocompatible, biodegradable, non-toxic, has antibacterial and osteoconductive properties. Chitosan is often used in the form of composites (with the participation of ceramic particles), membranes, hydrogels or nanoparticles. The problem with biomaterials is their low durability, rapid degradation, poor mechanical properties and cytotoxicity. Cross-linking or stabilization of such materials allows for solving these problems. It is important that the compounds used for this purpose exhibit limited or no toxicity. The presented article is a review and presents some methods of cross-linking/stabilization of chitosan structures. The analysis concerns low or non-cytotoxic cross-linking/stabilization methods. The discussed compounds used for the purpose of chitosan structure fixation are: cinnamaldehyde, genipin, L-aspartic acid, vanillin, sodium carbonate, sodium alginate, BGP, ethanol and TPP. There is discussed also a hydrothermal/dehydrothermal method which seems to be promising as it is more advantageous since no additional compounds are introduced into the structure.

Genipin-cross-linked hydrogels based on biomaterials for drug delivery: a review

Genipin is a naturally occurring nontoxic cross-linker, which has been widely used for drug delivery due to its excellent biocompatibility, admirable biodegradability and stable cross-linked attributes. These advantages led to its extensive application in the fabrication of hydrogels for drug delivery. This review describes the physicochemical characteristics and pharmacological activities of genipin and attempts to elucidate the detailed mechanisms of the cross-linking reaction between genipin and biomaterials. The current article entails a general review of the different biomaterials cross-linked by genipin: chitosan and its derivatives, collagen, gelatin, etc. The genipin-cross-linked hydrogels for various pharmaceutical applications, including ocular drug delivery, buccal drug delivery, oral drug delivery, anti-inflammatory drug delivery, and antibiotic and antifungal drug delivery, are reported. Finally, the future research directions and challenges of genipin-cross-linked hydrogels for pharmaceutical applications are also discussed in this review.

Genipin enhances the antitumor effect of elesclomol in A549 lung cancer cells by blocking uncoupling protein-2 and stimulating reactive oxygen species production

The uncoupling protein-2 (UCP2) serves a role in tumor aggressiveness and anticancer resistance, which is considered to be associated with its ability to attenuate reactive oxygen species (ROS) production. We hypothesized that UCP2 may protect cancer cells from elesclomol-induced cytotoxicity, and that this may be overcome by blocking UCP2 function with genipin. In A549 lung cancer cells that exhibited high UCP2 expression, treatment with elesclomol alone induced limited changes in glucose uptake, ROS production and cell survival. By contrast, both UCP2 knockdown and genipin treatment mildly reduced glucose uptake, increased ROS production and decreased cell survival. Combining genipin and elesclomol further reduced glucose uptake and increased cellular and mitochondrial ROS production. Moreover, co-treatment with genipin and elesclomol reduced the colony forming capacity to 50.6±7.4% and the cell survival to 42.0±3.4% of that in the control cells (both P<0.001). Suppression of cell survival by treatment with elesclomol and genipin was enhanced in the presence of an exogenous ROS inducer and attenuated by a ROS scavenger. The cytotoxic effects of combining genipin and elesclomol were accompanied by reduced mitochondrial membrane potential and occurred through apoptosis as demonstrated by Annexin V assay and increased protein cleavage of PARP and caspase-3. Finally, in an A549 ×enograft mouse model, tumor growth was only modestly retarded by treatment with elesclomol or genipin alone, but was markedly suppressed by combining the two drugs compared with that in the control group (P=0.008). Therefore, high UCP2 expression may limit the antitumor effect of elesclomol by attenuating ROS responses, and this may be overcome by co-treatment with genipin; combining elesclomol and genipin may be an effective strategy for treating cancers with high UCP2.

Genipin increases oxaliplatin-induced cell death through autophagy in gastric cancer

Oxaliplatin is used for treatment in combination with many drugs. However, the survival rate is still low due to side effects and drug resistance. Therefore, the combination with natural products was required for increasing efficacy and reducing side effects. Genipin, a natural product derived from the Gardenia jasminoides, associated with anti-angiogenic, anti-proliferative, hypertension, inflammatory, and the Hedgehog pathway. It is not known that genipin increases the therapeutic effect of oxaliplatin in gastric cancer. In this study, we found that genipin sensitizes oxaliplatin-induced apoptosis for the first time using colony forming assay, FACS analysis, and western blotting in gastric cancer. Additionally, genipin induced p53 expression in AGS, MKN45, and MKN28 cells. Also, genipin induced autophagy and LC3 expression. Knockdown of LC3 decreased cell death enhanced by the combination of oxaliplatin and genipin. In summary, we showed that genipin increases the oxaliplatin-induced cell death via p53-DRAM autophagy. Based on this, we suggest that genipin is a sensitizer of oxaliplatin.

In vitro bioactivity approach of unripe genipap (Genipa americana L., Rubiaceae) fruit extract and its solid lipid microparticle

Growing awareness in favor of innovative and healthier alternatives is creating a noticeable shift from synthetic colorants to natural additives. And, such a swing in the consumer market is growing slowly but noticeably. In this context, genipap (Genipa americana L.) fruit represents an emerging source of blue colorants in Latin America with extensive application possibilities. This is despite the fact that there are few studies concerning its toxicity predictive factors. In this early-stage study we propose to investigate safety issues around genipap extract (IBBP); we also attempt to identify fingerprint profiling of both IBBP extract and solid lipid microparticles containing IBBP extract (SLM-IBBP) using in vitro assays. The main compounds identified were genipin, and genipin 1-β-gentiobioside. Results indicated that IBBP extract, at 25 µg/mL, was able to promote DNA damage in CHO-K1 cells, suggesting a genotoxic effect. On the other hand, the SLM-IBBP inhibited almost all cancer cell lines with GI₅₀ ranging from 0.25 μg/mL to 43.5 μg/mL. Also, IBBP-SLM seems to exert a desirable apoptosis induction (at 25 µg/mL dosage). The next steps for our work, therefore, will focus on other nanoparticle formulation approaches, in particular with the use of natural Brazilian starch. An evaluation of the metabolism and distribution of microparticles, and their safety for food and pharmaceutical purposes, are also required.

Genipin Enhances the Therapeutic Effects of Oxaliplatin by Upregulating BIM in Colorectal Cancer

Despite an increase in the survival rate of patients with cancer owing to the use of current chemotherapeutic agents, adverse effects of cancer therapies remain a concern. Combination therapies have been developed to increase efficacy, reduce adverse effects, and overcome drug resistance. Genipin is a natural product derived from Gardenia jasminoides, which has been associated with anti-inflammatory, anti-angiogenic, and anti-proliferative effects; hypertension; and anti-ischemic brain injuries. However, the enhancement of oxaliplatin sensitivity by genipin remains unexplored. Our study showed that a combination of genipin and oxaliplatin exerts synergistic antitumor effects in vitro and in vivo in colorectal cancer cell lines through the reactive oxygen species (ROS)/endoplasmic reticulum (ER) stress/BIM pathway. Importantly, the combination did not affect normal colon cells. BIM knockdown markedly inhibited apoptosis induced by the combination. In addition, genipin induced ROS by inhibiting superoxide dismutase 3 activity. These findings suggest that genipin may be a novel agent for increasing the sensitivity of oxaliplatin against colorectal cancer. The combination of oxaliplatin and genipin hold significant therapeutic potential with minimal adverse effects.

Genipin induces cell death via intrinsic apoptosis pathways in human glioblastoma cells

Genipin, a compound derived from Gardenis jasminoides Ellis fruits, was demonstrated to be the specific uncoupling protein 2 (UCP2) inhibitor. UCP2 is a mitochondrial carrier protein that creates proton leaks across the inner mitochondrial membrane, thus uncoupling oxidative phosphorylation from adenosine triphosphate (ATP) synthesis. Several studies revealed that UCP2 is broadly over-expressed in leukemia, colorectal, lung, ovarian, prostate, testicular, and bladder cancers. However, the effect of genipin still needs to be elucidated in neurological malignancies. In this study, we investigated the anticancer effect of genipin in U87MG and A172 cell lines. The anticancer effect of genipin on these cell lines was measured by microculture tetrazoliumtest (MTT), Trypan blue exclusion, and colony formation assays, in the presence of various concentrations of genipin at different time intervals. We assessed apoptosis and measure intracellular reactive oxygen species (ROS) by flow cytometry. Expression of UCP2 and some of the genes involved in apoptosis was analyzed by real-time quantitative polymerase chain reaction (PCR). Results of the MTT assay showed that genipin moderately reduced metabolic activity of both cell lines in dose- and time-dependent manner. Result of Trypan blue exclusion test indicated that the viable cell count decreased in the treated group in a concentration-dependent manner. Genipin also significantly decreased colony formation ability of these cells in a concentration-dependent manner. Result of morphological changes showed that there were significant differences in cell number and morphology in treated groups as compared with the untreated groups. Flow cytometric analysis of U87MG and A172 cells with annexin V/propidium iodide staining, 48 hours after treatment with genipin, displays 22.4% and 26.1% apoptotic population, respectively, in treated cells, in comparison to 7.42% and 9.31% apoptotic cells of untreated cells. After treatment, UCP2 and B-cell lymphoma 2 (BCL ₂ ) genes are downregulated, and BCL ₂ associated X protein, BCL ₂ antagonist/killer, BCL ₂ interacting killer, and Cytochrome c genes are upregulated. Genipin treatment increased mitochondrial ROS levels and also induced apoptosis through caspase-3 upregulation. In conclusion, the antiproliferative effects of genipin on the growth of both glioblastoma cell lines have been shown in all of these assays, and genipin profoundly induced apoptosis in both cell lines via the UCP2-related mitochondrial pathway through the induction of intracellular ROS.

Therapeutic Potential and Effective Components of the Chinese Herb Gardeniae Fructus in the Treatment of Senile Disease

Gardeniae fructus (GF), an evergreen Rubiaceae shrub, is one of the most commonly used Chinese herbs in traditional Chinese medicine (TCM) and has been used for over a thousand years. It is usually prescribed for the treatment of brain aging, vascular aging, bone and joint aging, and other age-related diseases. It has been demonstrated that several effective compounds of GF, such as geniposide, genipin and crocin, have neuroprotective or related activities which are involved in senile disease treatment. These bioactivities include the mitochondrion dysfunction, antioxidative activity, apoptosis regulation and an anti-inflammatory activity, which related to multiple signaling pathways such as the nuclear factor-κB pathway, AMP-activated protein kinase signaling pathway, and the mitogen-activated protein kinase pathway. To lay the ground for fully elucidating the potential mechanisms of GF in treating age-related pathologies, we summarized the available research conducted in the last fifteen years about GF and its effective components, which have been studied in vivo and in vitro

HH1-1, a novel Galectin-3 inhibitor, exerts anti-pancreatic cancer activity by blocking Galectin-3/EGFR/AKT/FOXO3 signaling pathway

Pancreatic ductal adenocarcinoma is a highly malignant gastrointestinal tumor. Molecular targeting therapy for pancreatic cancer is still limited. High expressed Galectin-3 in pancreatic cancer is positively correlated with disease progression, indicating that Galectin-3 can be employed as a predictor of poor prognosis. From safflower, we isolated and purified a homogeneous polysaccharide, HH1-1, which could bind to and inhibit Galectin-3. HH1-1 could block the interaction between Galectin-3 and EGFR. Following HH1-1 treatment, the binding ability between EGFR and Galectin-3 was reduced by 245.28 folds. HH1-1 could suppress pancreatic cancer cell proliferation, arrest the cell cycle in S phase, induce cell apoptosis, inhibit angiogenesis and impede tumor cell migration and invasion. Moreover, HH1-1 affected the Galectin-3/EGFR/AKT/FOXO3 signaling pathway and possessed anti-pancreatic cancer activity in vitro and in vivo, especially in patient-derived xenografts. Further study suggested that HH1-1 had almost no toxicity both in vitro and in vivo. This adds new evidence to suggest that HH1-1 could be a promising therapeutic agent and support the pursuit of the Galectin-3 as a target in pancreatic cancer treatment.

Medicinal supplement genipin induces p53 and Bax-dependent apoptosis in colon cancer cells

Colorectal cancer (CRC) is the third leading cause of cancer-associated mortality worldwide. Genipin is a medicinal herb compound derived from the gardenia fruit, which has been reported to exhibit antitumor activity against several types of cancer. The aim of the present study was to investigate the antitumor effect of genipin on colon cancer and the underlying molecular mechanisms. Genipin significantly inhibited the viability of HCT116 and SW480 cells in vitro in a dose- and time-dependent manner. Additionally, genipin was able to significantly inhibit tumor growth in nude mice with xenografts of HCT116 and SW480 cells. The inhibition of tumor growth by genipin treatment was coupled with G0/G1 cell cycle arrest, apoptosis induction, increased reactive oxygen species damage and loss of mitochondrial membrane potential. Further investigation of genipin-treated HCT116 cells revealed that the expression of p53, Bax and cleaved caspase-3 in genipin-treated cells was increased compared with the vehicle control, whereas B-cell lymphoma-2 expression appeared to be lower in genipin-treated cells. Collectively, the findings of the present study indicate that genipin was able to decrease proliferation and promote apoptosis in colon cancer cells by inducing the p53/Bax-mediated signaling pathway. Therefore, genipin may be used as a novel therapeutic agent in the treatment of CRC.

Potential role of genipin in cancer therapy

Genipin, an aglycone derived from the iridoid glycoside, geniposide, is isolated and characterized from the extract of Gardenia jasminoides Ellis fruit (family Rubiaceae). It has long been used in traditional oriental medicine for the prevention and treatment of several inflammation driven diseases, including cancer. Genipin has been shown to have hepatoprotective activity acting as a potent antioxidant and inhibitor of mitochondrial uncoupling protein 2 (UCP2), and also reported to exert significant anticancer effects. It is an excellent crosslinking agent that helps to make novel sustained or delayed release nanoparticle formulations. In this review, we present the latest developments of genipin as an anticancer agent and briefly describe its diverse mechanism(s) of action. Several lines of evidence suggest that genipin is a potent inhibitor of UCP2, which functions as a tumor promoter in a variety of cancers, attenuates generation of reactive oxygen species and the expression of matrix metalloproteinase 2, as well as induces caspase-dependent apoptosis in vitro and in in vivo models. These finding suggests that genipin can serve as both a prominent anticancer agent as well as a potent crosslinking drug that may find useful application in several novel pharmaceutical formulations.

Plant-Derived Anticancer Agents: Lessons from the Pharmacology of Geniposide and Its Aglycone, Genipin

For centuries, plants have been exploited by mankind as sources of numerous cancer chemotherapeutic agents. Good examples of anticancer compounds of clinical significance today include the taxanes (e.g., taxol), vincristine, vinblastine, and the podophyllotoxin analogues that all trace their origin to higher plants. While all these drugs, along with the various other available therapeutic options, brought some relief in cancer management, a real breakthrough or cure has not yet been achieved. This critical review is a reflection on the lessons learnt from decades of research on the iridoid glycoside geniposide and its aglycone, genipin, which are currently used as gold standard reference compounds in cancer studies. Their effects on tumour development (carcinogenesis), cancer cell survival, and death, with particular emphasis on their mechanisms of actions, are discussed. Particular attention is also given to mechanisms related to the dual pro-oxidant and antioxidant effects of these compounds, the mitochondrial mechanism of cancer cell killing through reactive oxygen species (ROS), including that generated through the uncoupling protein-2 (UCP-2), the inflammatory mechanism, and cell cycle regulation. The implications of various studies for the evaluation of glycosidic and aglycone forms of natural products in vitro and in vivo through pharmacokinetic scrutiny are also addressed.

Selective induction of DNA damage, G2 abrogation, and mitochondrial apoptosis by leaf extract of traditional medicinal plant Wrightia arborea in K562 cells

Plants have proved to be an important source of anti-cancer drugs. Wrightia arborea, an Indian Ayurvedic medicinal plant, is used traditionally to treat a variety of ailments. This study evaluates the antiproliferative/apoptotic potential of Wrightia arborea leaf extracts, prepared in different organic solvents, on cancer cell lines. MTT assay, light and fluorescence microscopy, flow cytometry, DNA laddering, alkaline comet assay, and western blotting were some of the techniques used for evaluation. Combinations of camptothecin, either with CHK1 inhibitor-PD407824 or with W. arborea leaf extract, were deployed to determine the G2 abrogating potential of the extract. The chloroform extract (WAC) selectively killed K562 cells, without affecting cancerous MCF-7, Hep G2 cells, and normal human peripheral blood lymphocytes. Cell death was characterized by observation of apoptotic bodies, increased Ca2+ and ROS, phosphatidyl serine externalization, mitochondrial membrane depolarization, DNA laddering, increased sub-G1 population, and altered expression of caspase 3, -9, and PARP. WAC also induced DNA damage, alterations in key G2/M phase protein expression, cell cycle perturbation, and potent G2 abrogation. The present study showed that W. arborea leaf extract, WAC, is capable of selectively killing leukemic cancer cells leaving normal lymphocytes unaffected. Our results indicate that this is effectuated through DNA damage and G2 abrogation leading to mitochondrial apoptosis. Taken together, this report contributes toward a better understanding of the anticancer properties of this traditional medicinal plant extract possessing valuable bioactive constituents which can serve as a bioresource for promising complimentary/alternative/chemopreventive therapeutics.

Genipin inhibits the growth of human bladder cancer cells via inactivation of PI3K/Akt signaling

Genipin, a natural compound derived from the fruit of Gardenia jasminoides, possesses numerous biological properties. The aim of the present study was to investigate the anticancer effects of genipin in human bladder cancer. T24 and 5637 bladder cancer cells were treated with different concentrations of genipin (0-200 µM) and tested for cell viability, colony formation, cell cycle progression and apoptosis. A xenograft model of bladder cancer was established to determine the anticancer effect of genipin in vivo. The involvement of the phosphoinositide-3 kinase (PI3K)/Akt pathway in the action of genipin was examined. Genipin treatment significantly inhibited the viability and clonogenic growth of bladder cancer cells and inhibited the growth of T24 xenograft tumors, compared with vehicle controls (P<0.05). Genipin-treated cells exhibited a cell cycle arrest at the G0/G1-phase, which was accompanied by a deregulation of numerous cell cycle regulators. Genipin-treated cells demonstrated a significant increase in the percentage of apoptotic cells, loss of mitochondrial membrane potential, Bax translocation to the mitochondria and the release of cytochrome c to the cytosol. Additionally, genipin treatment significantly (P<0.05) reduced the phosphorylation levels of PI3K and Akt in bladder cancer cells. Importantly, genipin-mediated anticancer effects were reversed by the overexpression of constitutively active Akt. In conclusion, to the best of our knowledge, the present study demonstrates for the first time the growth inhibitory effects of genipin in bladder cancer cells, and indicates its potential as a natural anticancer agent for bladder cancer.

The Hydroxyl at Position C1 of Genipin Is the Active Inhibitory Group that Affects Mitochondrial Uncoupling Protein 2 in Panc-1 Cells

Genipin (GNP) effectively inhibits uncoupling protein 2 (UCP2), which regulates the leakage of protons across the inner mitochondrial membrane. UCP2 inhibition may induce pancreatic adenocarcinoma cell death by increasing reactive oxygen species (ROS) levels. In this study, the hydroxyls at positions C10 (10-OH) and C1 (1-OH) of GNP were hypothesized to be the active groups that cause these inhibitory effects. Four GNP derivatives in which the hydroxyl at position C10 or C1 was replaced with other chemical groups were synthesized and isolated. Differences in the inhibitory effects of GNP and its four derivatives on pancreatic carcinoma cell (Panc-1) proliferation were assessed. The effects of GNP and its derivatives on apoptosis, UCP2 inhibition and ROS production were also studied to explore the relationship between GNP’s activity and its structure. The derivatives with 1-OH substitutions, geniposide (1-GNP1) and 1-ethyl-genipin (1-GNP2) lacked cytotoxic effects, while the other derivatives that retained 1-OH, 10-piv-genipin (10-GNP1) and 10-acetic acid-genipin (10-GNP2) exerted biological effects similar to those of GNP, even in the absence of 10-OH. Thus, 1-OH is the key functional group in the structure of GNP that is responsible for GNP’s apoptotic effects. These cytotoxic effects involve the induction of Panc-1 cell apoptosis through UCP2 inhibition and subsequent ROS production.

Hypericin-mediated photodynamic therapy induces apoptosis in K562 human leukemia cells through JNK pathway modulation

Hypericin (Hyp) is traditionally used as an antidepressant and antiviral agent. It selectively accumulates in spheroids and is also used as a photosensitizer in the photodynamic therapy of cancer. The present study aimed to investigate the cytotoxic effect of Hyp-mediated photodynamic therapy (Hyp-PDT) on cell growth and apoptosis of K562 leukemia cells, and to examine the underlying mechanisms. Hyp-PDT was performed with different light intensities (0.1, 0.3 and 0.5 mW/cm²), different concentrations of Hyp (0, 0.2, 0.4 and 0.8 µg/ml) and different durations of irradiation (0, 2, 4 and 8 min) in order to select the optimal conditions for subsequent experiments. A concentration of 0.4 µg/ml Hyp with a 5 h drug-light interval and 4 min irradiation at 0.3 mW/cm² light intensity was selected as the optimal conditions. The effects of Hyp-PDT on apoptosis were determined by detecting morphological changes under microscopy and by performing western blot analysis. The results revealed that Hyp-PDT suppressed cell viability in a light intensity-, dose- and irradiation duration-dependent manner. The expression levels of cleaved caspase-9, cleaved caspase-3 and phosphorylated-C-Jun N terminal kinase (JNK) l were significantly upregulated following Hyp-PDT. These results indicated that Hyp-PDT decreased cell viability and induced mitochondria-caspase-dependent apoptosis in the K562 cells through regulation of the JNK pathway. These findings suggest that Hyp-PDT may be developed as an effective treatment for leukemia.

Induction of apoptosis by genipin inhibits cell proliferation in AGS human gastric cancer cells via Egr1/p21 signaling pathway

Natural compounds are becoming important candidates in cancer therapy due to their cytotoxic effects on cancer cells by inducing various types of programmed cell deaths. In this study, we investigated whether genipin induces programmed cell deaths and mediates in Egr1/p21 signaling pathways in gastric cancer cells. Effects of genipin in AGS cancer cell lines were observed via evaluation of cell viability, ROS generation, cell cycle arrest, and protein and RNA levels of p21, Egr1, as well as apoptotic marker genes. The cell viability of AGS cells reduced by genipin treatment via induction of the caspase 3-dependent apoptosis. Cell cycle arrest was observed at the G2/M phase along with induction of p21 and p21-dependent cyclins. As an upstream mediator of p21, the transcription factor early growth response-1 (Egr1) upregulated p21 through nuclear translocation and binding to the p21 promoter site. Silencing Egr1 expression inhibited the expression of p21 and downstream molecules involved in apoptosis. We demonstrated that genipin treatment in AGS human gastric cancer cell line induces apoptosis via p53-independent Egr1/p21 signaling pathway in a dose-dependent manner.

Oleuropein induced apoptosis in HeLa cells via a mitochondrial apoptotic cascade associated with activation of the c-Jun NH2-terminal kinase

Oleuropein could inhibit growth and/or induce apoptosis in several cancer cell lines. In this study, we investigate how oleuropein strongly induces apoptotic cell death in HeLa human cervical carcinoma cells. Oleuropein induced HeLa cells apoptosis as demonstrated by induction of a sub-G(1) peak in flow cytometry and apoptosis-related morphological changes observed by fluorescence microscopy after being stained by Hoechst 33324. The results also showed that 150 - 200 μM oleuropein&ndash;treated HeLa cells were arrested at the G(2)/M phase. Western blot analysis revealed that the phosphorylated ATF-2, c-Jun NH(2)-terminal kinase (JNK) protein, p53, p21, Bax, and cytochrome c protein in the cytoplasm significantly increased in a dose-dependent manner after treatment of oleuropein for 24 h. Additionally, increasing levels of Bax in response to JNK/SPAK signaling, which formed mitochondrial membrane channels, accounted for releasing of cytochrome c and activation of caspase-9 and -3. SP600125 (20 μM), a JNK(1/2) inhibitor, markedly suppressed the formation of apoptotic bodies and JNK activation induced by oleuropein at 200 μM. Thus, oleuropein-induced apoptosis was activated by the JNK/SPAK signal pathway. The result shows that oleuropein holds promise as a potential chemotherapeutic agent for the treatment of HeLa cells.

Terrein induces apoptosis in HeLa human cervical carcinoma cells through p53 and ERK regulation

Terrein, a fungal metabolite derived from Aspergillus terreus, has been shown to have a variety of biological activities in human cells including inhibition of melanogenesis, as well as anti-inflammatory, antioxidant and anticancer properties. In the present study, terrein was shown to have marked anticancer activity on HeLa human cervical carcinoma cells. Terrein exhibited inhibition of proliferation within the same ranges for other cancer cell types with an IC50 at 0.29 mM. The growth inhibition that induced cell death was via apoptosis mechanisms. Chromatin condensation was observed using the Hoechst 33342 stain, a DNA-specific dye. The increase of DNA fragmentation or the sub-G0 peak was also detected by flow cytometry. The signaling used by terrein to induce apoptosis was via the death-receptor and mitochondrial pathways; the cleavage of specific fluorogenic substrates by caspase-3, -8 and -9 activities are clearly demonstrated. The mitochondria were damaged as demonstrated by the decrease of the red/green ratio of the JC-1 staining and the increase of the Bax/Bcl-2 expression ratio. Further analysis of the upstream signaling by the quantitative real-time polymerase chain reaction showed that p53, p21 and ERK were upregulated which indicates the importance of their roles on terrein signaling. This study is the first to show that terrein has an effect on the anticancer properties in cervical cancer cells by inducing apoptosis through p53 and ERK regulation. Our data may help expand the function of the terrein compound and may also aid in the discovery of new anticancer agents.

The protective effect of 17β-estradiol against hydrogen peroxide-induced apoptosis on mesenchymal stem cell

This study was designed to investigate the function of 17β-estradiol (17β-E2) against oxidative stress on the cell death of mice bone marrow mesenchymal stem cells (BMSCs) induced by hydrogen peroxide (H₂O₂). BMSCs were treated with 17β-E2 for 24h and then treated with 100μM H₂O₂ for 1h. Cell viability, apoptosis, caspase-9 mRNA, JNKs (Jun N-terminal kinases) and c-Jun protein expression in BMSCs were evaluated. Cell apoptosis of BMSCs were increased in a dose-dependent manner after treated with H₂O₂ compared to control group. But pretreatment with 17β-E2 can inhibit apoptosis of BMSCs, preserve the mitochondrial transmembrane potential, decrease caspase-9 mRNA, JNK1/2 and c-Jun protein expression. In conclusion, 17β-E₂ exerts antiapoptotic effects in BMSCs which related to the mitochondria death pathway and JNKs pathway. The study revealed that 17β-E₂ can reduce the donor stem cells damage.