Enhanced killing of cervical cancer cells by combinations of methyl jasmonate with cisplatin, X or alpha radiation. Invest New Drugs. 2013;31:333-344. [PMID: 22956285 DOI: 10.1007/s10637-012-9870-2]

First measurements of radon-220 diffusion in mice tumors, towards treatment planning in diffusing alpha-emitters radiation therapy

BACKGROUND

Diffusing alpha-emitters radiation therapy ("Alpha-DaRT") is a new method for treating solid tumors with alpha particles, relying on the release of the short-lived alpha-emitting daughter atoms of radium-224 from interstitial sources inserted into the tumor. Alpha-DaRT tumor dosimetry is governed by the spread of radium's progeny around the source, as described by an approximate framework called the "diffusion-leakage model". The most important model parameters are the diffusion lengths of radon-220 and lead-212, and their estimation is therefore essential for treatment planning.

PURPOSE

Previous works have provided initial estimates for the dominant diffusion length, by measuring the activity spread inside mice-borne tumors several days after the insertion of an Alpha-DaRT source. The measurements, taken when lead-212 was in secular equilibrium with radium-224, were interpreted as representing the lead-212 diffusion length. The aim of this work is to provide first experimental estimates for the diffusion length of radon-220, using a new methodology.

METHODS

The diffusion length of radon-220 was estimated from autoradiography measurements of histological sections taken from 24 mice-borne subcutaneous tumors of five different types. Unlike previous studies, the source dwell time inside the tumor was limited to 30 min, to prevent the buildup of lead-212. To investigate the contribution of potential non-diffusive processes, experiments were done in two sets: fourteen in vivo tumors, where during the treatment the tumors were still carried by the mice with active blood supply, and 10 ex-vivo tumors, where the tumors were excised before source insertion and kept in a medium at37 ∘ C $37^\circ {\text{C}}$ with the source inside.

RESULTS

The measured diffusion lengths of radon-220, extracted by fitting the recorded activity pattern up to 1.5 mm from the source, lie in the range0.25 - 0.6 mm ${0.25-0.6}\nobreakspace {\text{mm}}$ , with no significant difference between the average values measured in in-vivo and ex-vivo tumors:L R n i n - v i v o = 0.40 ± 0.08 mm $L_{Rn}^{in-vivo}=0.40{\pm }0.08\nobreakspace {\text{mm}}$ versusL R n e x - v i v o = 0.39 ± 0.07 mm $L_{Rn}^{ex-vivo}=0.39{\pm }0.07\nobreakspace {\text{mm}}$ . However, in-vivo tumors display an enhanced spread of activity 2-3 mm away from the source. This effect is not explained by the current model and is much less pronounced in ex-vivo tumors.

CONCLUSIONS

The average measured radon-220 diffusion lengths in both in-vivo and ex-vivo tumors are consistent with published data on the diffusion length of radon in water and lie close to the upper limit of the previously estimated range of0.2 - 0.4 mm $0.2-0.4\nobreakspace {\text{mm}}$ . The observation that close to the source there is no apparent difference between in-vivo and ex-vivo tumors, and the good agreement with the theoretical model in this region suggest that the spread of radon-220 is predominantly diffusive in this region. The departure from the model prediction in in-vivo tumors at large radial distances may hint at potential vascular contribution, which will be the subject of future works.

EZH2 activates Wnt/β-catenin signaling in human uterine fibroids, which is inhibited by the natural compound methyl jasmonate

OBJECTIVE

To investigate the link between EZH2 and Wnt/β-catenin signaling and its role in uterine fibroids (UFs) pathogenesis and explore the potential effect of natural compound methyl jasmonate (MJ) against UFs.

DESIGN

EZH2 overexpression or inhibition was achieved in human uterine leiomyoma (HuLM) cells using EZH2-expressing adenovirus or chemical EZH2 inhibitor (DZNep), respectively. The HuLM and normal uterine smooth muscle cells were treated with 0.1-3 mM of MJ, and several experiments were employed.

SETTING

Laboratory study.

PATIENTS(S)

None.

INTERVENTION(S)

Methyl jasmonate.

MAIN OUTCOME MEASURE(S)

Protein expression of EZH2, β-catenin, and proliferating cell nuclear antigen (PCNA) was measured by Western blot as well as gene expression alterations of Wnt ligands (Wnt5A, Wnt5b, and Wnt9A), WISP1, CTNNB1, and its responsive gene PITX2 using quantitative real-time polymerase chain reaction. The protein and ribonucleic acid (RNA) levels of several markers were measured in MJ-treated or untreated HuLM cells, including EZH2 and β-catenin, extracellular matrix markers collagen type 1 (COL1A1) and fibronectin (FN), proliferation markers cyclin D1 (CCND1) and PCNA, tumor suppressor marker p21, and apoptotic markers (BAX, cytochrome c, and cleaved caspase 3).

RESULT(S)

EZH2 overexpression significantly increased the gene expression of several Wnt ligands (PITX2, WISP1, WNT5A, WNT5B, and WNT9A), which increased nuclear translocation of β-catenin and PCNA and eventually HuLM cell proliferation. EZH2 inhibition blocked Wnt/β-catenin signaling activation where the aforementioned genes significantly decreased as well as PCNA, cyclin D1, and PITX2 protein expression compared with those in untreated HuLM. Methyl jasmonate showed a potent antiproliferative effect on HuLM cells in a dose- and time-dependent manner. Interestingly, the dose range (0.1-0.5 mM) showed a selective growth inhibitory effect on HuLM cells, not on normal uterine smooth muscle cells. Methyl jasmonate treatment at 0.5 mM for 24 hours significantly decreased both protein and RNA levels of EZH2, β-catenin, COL1A1, FN, CCND1, PCNA, WISP1, and PITX2 but increased the protein levels of p21, BAX, cytochrome, c and cleaved caspase 3 compared with untreated HuLM. Methyl jasmonate-treated cells exhibited down-regulation in the RNA expression of 36 genes, including CTNNB1, CCND1, Wnt5A, Wnt5B, and Wnt9A, and up-regulation in the expression of 34 genes, including Wnt antagonist genes WIF1, PRICKlE1, and DKK1 compared with control, confirming the quantitative real-time polymerase chain reaction results.

CONCLUSION(S)

Our studies provide a novel link between EZH2 and the Wnt/β-catenin signaling pathway in UFs. Targeting EZH2 with MJ interferes with the activation of wnt/β-catenin signaling in our model. Methyl jasmonate may offer a promising therapeutic option as a nonhormonal and cost-effective treatment against UFs with favorable clinical utility, pending proven safe and efficient in human clinical trials.

Alpha dose modeling in diffusing alpha-emitters radiation therapy-Part I: single-seed calculations in one and two dimensions

BACKGROUND

Diffusing alpha-emitters Radiation Therapy ("DaRT") is a new method, presently in clinical trials, which allows treating solid tumors by alpha particles. DaRT relies on interstitial seeds carrying μCi-level ²²⁴ Ra activity below their surface, which release a chain of short-lived alpha emitters that spread throughout the tumor volume primarily by diffusion. Alpha dose calculations in DaRT are based on describing the transport of alpha emitting atoms, requiring new modeling techniques.

PURPOSE

A previous study introduced a simplified framework, the "Diffusion-Leakage (DL) model", for DaRT alpha dose calculations, and employed it to a point source, as a basic building block of arbitrary configurations of line sources. The aim of this work, which is divided into two parts, is to extend the model to realistic seed geometries (in Part I), and to employ single-seed calculations to study the properties of DaRT seed lattices (Part II). Such calculations can serve as a pragmatic guide for treatment planning in future clinical trials.

METHODS

We derive a closed-form asymptotic solution for an infinitely long cylindrical source, and extend it to an approximate time-dependent expression that assumes a uniform temporal profile at all radial distances from the source. We then develop a finite-element one-dimensional numerical scheme for a complete time-dependent solution of this geometry and validate it against the closed-form expressions. Finally, we discuss a two-dimensional axisymmetric scheme for a complete time-dependent solution for a seed of finite diameter and length. Different solutions are compared over the relevant parameter space, providing guidelines on their usability and limitations.

RESULTS

We show that approximating the seed as a finite line source comprised of point-like segments significantly underestimates the correct alpha dose, as predicted by the full two-dimensional calculation. The time-dependent one-dimensional solution is shown to coincide to sub-percent-level with the two-dimensional calculation in the seed midplane, and maintains an accuracy of a few percent up to ∼2 mm from the seed edge.

CONCLUSIONS

For actual treatment plans, the full two-dimensional solution should be used to generate dose lookup tables, similarly to the TG-43 format employed in conventional brachytherapy. Given the accuracy of the one-dimensional solution up to ∼2 mm from the seed edge it can be used for efficient parametric studies of DaRT seed lattices.

Therapeutic Potential of Jasmonic Acid and Its Derivatives

A modern method of therapeutic use of natural compounds that would protect the body are jasmonates. The main representatives of jasmonate compounds include jasmonic acid and its derivatives, mainly methyl jasmonate. Extracts from plants rich in jasmonic compounds show a broad spectrum of activity, i.e., anti-cancer, anti-inflammatory and cosmetic. Studies of the biological activity of jasmonic acid and its derivatives in mammals are based on their structural similarity to prostaglandins and the compounds can be used as natural therapeutics for inflammation. Jasmonates also constitute a potential group of anti-cancer drugs that can be used alone or in combination with other known chemotherapeutic agents. Moreover, due to their ability to stimulate exfoliation of the epidermis, remove discoloration, regulate the function of the sebaceous glands and reduce the visible signs of aging, they are considered for possible use in cosmetics and dermatology. The paper presents a review of literature data on the biological activity of jasmonates that may be helpful in treatment and prevention.

Jasmonate Compounds and Their Derivatives in the Regulation of the Neoplastic Processes

Cancer is a serious problem in modern medicine, mainly due to the insufficient effectiveness of currently available therapies. There is a particular interest in compounds of natural origin, which can be used in the prophylaxis, as well as in the treatment and support of cancer treatment. One such compound is jasmonic acid (3-oxo-2-(pent-2'-enyl)cyclopentane acetic acid; isolated active form: trans-(-)-(3R,7R)- and cis-(+)-(3R,7S)-jasmonic acid) and its derivatives, which, due to their wide range of biological activities, are also proposed as potential therapeutic agents. Therefore, a review of literature data on the biological activity of jasmonates was prepared, with particular emphasis on the mechanisms of jasmonate action in neoplastic diseases. The anti-tumor activity of jasmonate compounds is based on altered cellular ATP levels; induction of re-differentiation through the action of Mitogen Activated Protein Kinases (MAPKs); the induction of the apoptosis by reactive oxygen species. Jasmonates can be used in anti-cancer therapy in combination with other known drugs, such as cisplatin, paclitaxel or doxorubicin, showing a synergistic effect. The structure-activity relationship of novel jasmonate derivatives with anti-tumor, anti-inflammatory and anti-aging effects is also shown.

Oncolytic adenoviral H101 synergizes with radiation in cervical cancer cells

BACKGROUND

A major challenge in cervical cancer radiotherapy is to tailor the radiation doses efficiently to both eliminate malignant cells and to reduce the side effects to normal tissue. Oncolytic adenoviral drug H101 is recently tested and approved for topical adjuvant treatment of several malignancies.

OBJECTIVE

This study is to evaluate the potential neoadjuvant radiotherapy benefits of H101 by testing the inhibitory function of H101 combined with radiation in different cervical cancer cells.

METHODS

Human cervical cancer cells C33a, SiHa, CaSki, and Hela were treated with varying concentrations of H101 alone or combined with radiation (2Gy or 4Gy). Cell viability and apoptosis were measured at indicated time intervals. HPV16 E6 and cellular p53 mRNA expression alteration were measured by qRT-PCR. RNA scope in-situ detect HPV E6 status. P53 protein alteration are detected by Western blot.

RESULTS

Cell viability and apoptosis show the combination of a high dose of H101 (MOI=1000, 10000) with radiation yielded a synergistic anti-cancer effect in all tested cervical cancer cell lines (P<0.05), with the greatest effect achieved in HPV negative C33a cells (P<0.05). Low HPV16 viral load SiHa cell was more sensitive to combination therapy than high HPV16 viral load CaSki cell (P<0.05). The combined treatment could reduce HPV16 E6 expression and increase cellular P53 level compared to radiation alone in SiHa and CaSki (P<0.05).

CONCLUSIONS

Oncolytic adenoviral H101 effectively enhances the antitumor efficacy of radiation in cervical cancer cells and may serve as a novel combination therapy for cervical cancer.

Chloroform fraction of Chaetomorpha brachygona, a marine green alga from Indian Sundarbans inducing autophagy in cervical cancer cells in vitro

Sundarbans Mangrove Ecosystem (SME) is a rich repository of bioactive natural compounds, with immense nutraceutical and therapeutic potential. Till date, the algal population of SME was not explored fully for their anticancer activities. Our aim is to explore the potential of these algal phytochemicals against the proliferation of cervical cancer cells (in vitro) and identify the mode of cell death induced in them. In the present work, the chloroform fraction of marine green alga, Chaetomorpha brachygona was used on SiHa cell line. The algal phytochemicals were identified by GCMS, LCMS and column chromatography and some of the identified compounds, known for significant anticancer activities, have shown strong Bcl-2 binding capacity, as analyzed through molecular docking study. The extract showed cytostatic and cytotoxic activity on SiHa cells. Absence of fragmented DNA, and presence of increased number of acidic vacuoles in the treated cells indicate nonapoptotic cell death. The mode of cell death was likely to be autophagic, as indicated by the enhanced expression of Beclin 1 and LC3BII (considered as autophagic markers) observed by Western blotting. The study indicates that, C. brachygona can successfully inhibit the proliferation of cervical cancer cells in vitro.

MAPK4 deletion enhances radiation effects and triggers synergistic lethality with simultaneous PARP1 inhibition in cervical cancer

BACKGROUND

Cervical cancer is one of the most common cancers among females worldwide and advanced patients have extremely poor prognosis. However, adverse reactions and accumulating resistance to radiation therapy require further investigation.

METHODS

The expression levels of mitogen-activated protein kinase 4 (MAPK4) mRNA were analyzed by real-time PCR and its association with overall survival was analyzed using Kaplan-Mier method. Colony formation, immunofluorescence and western blotting were used to examine the effects of MAPK4 knockout or over-expression on cervical cancer cells after radiation treatment. Drug-sensitivity of cervical cancer cells to PARP1 inhibitors, olaparib or veliparib, was analyzed by CCK-8 cell viability assays, and the 50% inhibitory concentration (IC50) was quantified using GraphPad Prism. The functional effects of MAPK4 knockout on the sensitivity of cervical cancer to radiation treatment and PARP1 inhibitors were further examined using xenograft tumor mouse models in vivo.

RESULTS

Cervical cancer patients with high MAPK4 mRNA expression have lower survival rate. After radiation treatment, the colony number of MAPK4 knockout cells was markedly reduced, and the markers for DNA double-chain breakage were significantly up-regulated. In addition, MAPK4 knockout reduced protein kinase B (AKT) phosphorylation, whereas its over-expression resulted in opposite effects. In MAPK4 KO cells with irradiation treatment, inhibition of AKT phosphorylation promoted DNA double-chain breakage. Constitutive activation of AKT (CA-AKT) increased the levels of phosphorylated-AKT (p-AKT), and DNA repair-related proteins, phosphorylated-DNA-dependent protein kinase (p-DNA-PK) and RAD51 recombinase (RAD51). Furthermore, MAPK4 knockout was found to affect the sensitivity of cervical cancer cells to poly ADP-ribose polymerase 1 (PARP1) inhibitors by activating the phosphorylation of AKT. Moreover, in vivo results demonstrated that MAPK4 knockout enhanced the sensitivity of cervical cancer to radiation and PARP1 inhibitors in mouse xenograft models.

CONCLUSIONS

Collectively, our data suggest that combined application of MAPK4 knockout and PARP1 inhibition can be used as therapeutic strategy in radiation treatment for advanced cervical carcinoma.

Diffusing alpha-emitters radiation therapy: approximate modeling of the macroscopic alpha particle dose of a point source

Diffusing alpha-emitters radiation therapy ('DaRT') is a new cancer-treatment modality, which enables treating solid tumors by alpha particles. The treatment utilizes implantable seeds embedded with a low activity of radium-224. Each seed continuously emits the short-lived alpha-emitting daughters of radium-224, which spread over several mm around it, creating a 'kill region' of high alpha-particle dose. DaRT is presently tested in clinical trials, starting with locally advanced and recurrent squamous cell carcinoma (SCC) of the skin and head and neck, with promising results with respect to both efficacy and safety. This work aims to provide a simple model which can serve as a zero-order approximation for DaRT dosimetry, allowing for calculating the macroscopic alpha particle dose of a point source, as a basis for more realistic source geometries. The model consists of diffusion equations for radon-220, lead-212 and bismuth-212, with the other short-lived daughters in local secular equilibrium. For simplicity, the medium is assumed to be homogeneous, isotropic and time-independent. Vascular effects are accounted for by effective diffusion and clearance terms. To leading order, the alpha particle dose can be described by simple analytic expressions, which shed light on the underlying physics. The calculations demonstrate that, for a reasonable choice of model parameters, therapeutic alpha-particle dose levels are obtained over a region measuring 4-7 mm in diameter for sources carrying a few [Formula: see text]Ci of radium-224. The model predictions served as the basis for treatment planning in the SCC clinical trial, where treatments employing DaRT seeds carrying 2 [Formula: see text]Ci of radium-224 and spaced 5 mm apart resulted in  ∼[Formula: see text] complete response of the treated tumors with no observed radiation-induced toxicity. The promising results of the SCC clinical trial indicate that in spite of its approximate nature, the simple diffusion-based dosimetry model provides a quantitative starting point for DaRT treatment planning.

Initial Safety and Tumor Control Results From a "First-in-Human" Multicenter Prospective Trial Evaluating a Novel Alpha-Emitting Radionuclide for the Treatment of Locally Advanced Recurrent Squamous Cell Carcinomas of the Skin and Head and Neck

PURPOSE

Our purpose was to report the feasibility and safety of diffusing alpha-emitter radiation therapy (DaRT), which entails the interstitial implantation of a novel alpha-emitting brachytherapy source, for the treatment of locally advanced and recurrent squamous cancers of the skin and head and neck.

METHODS AND MATERIALS

This prospective first-in-human, multicenter clinical study evaluated 31 lesions in 28 patients. The primary objective was to determine the feasibility and safety of this approach, and the secondary objectives were to evaluate the initial tumor response and local progression-free survival. Eligibility criteria included all patients with biopsy-proven squamous cancers of the skin and head and neck with either primary tumors or recurrent/previously treated disease by either surgery or prior external beam radiation therapy; 13 of 31 lesions (42%) had received prior radiation therapy. Toxicity was evaluated according to the Common Terminology Criteria for Adverse Events version 4.03. Tumor response was assessed at 30 to 45 days at a follow-up visit using the Response Evaluation Criteria in Solid Tumors, version 1.1. Median follow-up time was 6.7 months.

RESULTS

Acute toxicity included mostly local pain and erythema at the implantation site followed by swelling and mild skin ulceration. For pain and grade 2 skin ulcerations, 90% of patients had resolution within 3 to 5 weeks. Complete response to the Ra-224 DaRT treatment was observed in 22 lesions (22/28; 78.6%); 6 lesions (6/28, 21.4%) manifested a partial response (>30% tumor reduction). Among the 22 lesions with a complete response, 5 (22%) developed a subsequent local relapse at the site of DaRT implantation at a median time of 4.9 months (range, 2.43-5.52 months). The 1-year local progression-free survival probability at the implanted site was 44% overall (confidence interval [CI], 20.3%-64.3%) and 60% (95% CI, 28.61%-81.35%) for complete responders. Overall survival rates at 12 months post-DaRT implantation were 75% (95% CI, 46.14%-89.99%) among all patients and 93% (95% CI, 59.08%-98.96%) among complete responders.

CONCLUSIONS

Alpha-emitter brachytherapy using DaRT achieved significant tumor responses without grade 3 or higher toxicities observed. Longer follow-up observations and larger studies are underway to validate these findings.

Protoberberine compounds extracted from Chelidonium majus L. as novel natural photosensitizers for cancer therapy

BACKGROUND

It has been shown that secondary metabolites occur in Chelidonium majus L. (C. majus) crude extract and milky sap (alkaloids such as berberine, coptisine, chelidonine, chelerythrine, sanguinarine, and protopine) are biologically active compounds with a wide spectrum of pharmacological functions. Berberine, an isoquinoline alkaloid extracted from plants, possesses a wide range of biological activities, including inhibition of growth of a variety of cancer cell lines.

PURPOSE AND STUDY DESIGN

In the present study, we investigated the potential anticancer effect of a protoberberine alkaloidal fraction (BBR-F) isolated from the medicinal plant C. majus on HeLa and C33A cervical cancer cells after light irradiation (PDT treatment).

METHODS

BBR-F was prepared from an ethanolic extract of stems of C. majus. Identification of alkaloidal compounds was performed using high-performance liquid chromatography - mass spectrometry (HPLC/ESI-MS) and nuclear magnetic resonance (NMR) spectroscopy. BBR-F was then biologically evaluated for its anticancer properties. Cytotoxic activity after PDT treatment and without light irradiation (dark cytotoxicity) was determined by colorimetric WST-1 assay. The impact of the protoberberine alkaloidal fraction on the morphology and function of the cells was assessed by fluorescence and confocal microscopy as well as by flow cytometric analysis. To investigate the proinflammatory effect of the extracted natural BBR-F, nitric oxide concentration was determined using the Griess method.

RESULTS

An effective reduction in HeLa and C33A cell viability was observed after PDT treatment of BBR-F treated cells. Furthermore, microscopic analysis identified various morphological changes in the studied cells that occurred during apoptosis. Apoptosis of HeLa and C33A cells was also characterized by biochemical changes in cell membrane composition, activation of intracellular caspases, disruption of the mitochondrial membrane potential (Δψm) and reactive oxygen species (ROS) generation.

CONCLUSION

Our results strongly suggest that the components of the natural plant protoberberine fraction (BBR-F) extracted from C. majus may represent promising novel photosensitive agents and can be applied in cancer photodynamic therapy as natural photosensitizers.

Methyl jasmonate enhances the radiation sensitivity of esophageal carcinoma cells by inhibiting the 11-ketoprostaglandin reductase activity of AKR1C3

Purpose

In our previous study, we found that AKR1C3 was a radioresistance gene in KY170R cells. Downregulating the expression of AKR1C3 could enhance the radiosensitivity of esophageal carcinoma cells. In this study, we investigated whether methyl jasmonate (MeJ), an inhibitor of Aldo-keto reductase family1 member C3 (AKR1C3), could overcome radiation resistance in AKR1C3 highly expressed cells.

Patients and methods

We used clone formation assays to detect radiosensitivity effects. Flow cytometry assays were used to detect reactive oxygen species (ROS) accumulation and apoptosis. Enzyme linked immunosorbent assays (ELISAs) were used to detect the concentrations of prostaglandin F2 (PGF2) and prostaglandin D2 (PGD2) in the cells after incubation with MeJ. Western blotting was used to detect AKR1C3 and peroxisome proliferator-activated receptor gamma (PPARγ) expression.

Results

We found that AKR1C3 was highly expressed in radioresistant esophageal carcinoma cells. MeJ inhibited the expression of AKR1C3 and enhanced the radiation sensitivity of esophageal carcinoma cells expressing high levels of AKR1C3 (P<0.05). MeJ could inhibit the 11-ketoprostaglandin reductase activity of AKR1C3 in a dose-dependent manner in KY170R cells. Incubation of KY170R cells with 200 µmol/L of MeJ for 24 h reduced the expression of PGF2 by roughly 30% (P<0.05). The PPAR pathway inhibitor GW9662 prevented the radiation sensitivity enhancement imparted by MeJ. After adding GW9662, there were no significant differences between the radiation sensitivities of MeJ-treated and -untreated KY170R cells (P>0.05). The radiation sensitivity effect of MeJ also depended upon the generation of ROS in KY170R cells; 48 h after irradiation, ROS levels in the MeJ group was twofold higher than in the untreated KY170R cells (P<0.05). The ROS scavenger, N-acetyl cysteine, could reverse the radiosensitivity effects of MeJ (P>0.05).

Conclusion

Our results indicate that MeJ can increase the radiation sensitivity of AKR1C3-overexpressing KY170R cells by inhibiting the 11-ketoprostaglandin reductase activity of AKR1C3 and increasing cellular ROS levels.

Synergistic anti-oral cancer effects of UVC and methanolic extracts of Cryptocarya concinna roots via apoptosis, oxidative stress and DNA damage

Purpose Radiation combined with natural products may improve the radiosensitivity of cancer cells. This study investigated the potential of a combined modality treatment with Ultraviolet C (UVC; wavelength range 200-280 nm) and our previously identified anti-oral cancer agent (methanolic extracts of Cryptocarya concinna roots; MECCrt) in oral cancer cells. Materials and methods The mechanism of the possible synergy of UVC and MECCrt was explored in terms of cell viability, cell cycle, apoptosis, reactive oxygen species (ROS), mitochondrial membrane potential (MitoMP), and DNA damage analyses. Results In cell viability (%) at 24 h treatment, the low doses of UVC (14 J/m(2)) and MECCrt (10 μg/ml) resulted in slight damage to human oral cancer Ca9-22 cells (83.2 and 80.4) but was less harmful to human oral normal HGF-1 cells (93.4 and 91.8, respectively). The combined treatment of UVC and MECCrt (UVC/MECCrt) had a lower viability (54.5%) than UVC or MECCrt alone in Ca9-22 cells but no showed significant change in HGF-1 cells. In Ca9-22 cells, the expression of flow cytometry-based apoptosis (sub-G1 phase, annexin V, and pancaspase assays) was significantly higher in UVC/MECCrt than in UVC or MECCrt alone (p < 0.0001). Using flow cytometry, intracellular ROS levels of UVC/MECCrt and MECCrt alone were higher than for UVC alone. MitoMP change and H2A histone family member X (γH2AX; H2AFX)-based DNA damage were synergistically inhibited and induced by MECCrt/UVC compared to its single treatment in Ca9-22 cells, respectively. Conclusion UVC plus MECCrt treatment had selective killing and synergistic anti-proliferative effects against oral cancer cells involving apoptosis, oxidative stress, and DNA damage. This combination therapy appears to have a great clinical potential against oral cancer cells.

Metabolic interplay between glycolysis and mitochondrial oxidation: The reverse Warburg effect and its therapeutic implication

Aerobic glycolysis, i.e., the Warburg effect, may contribute to the aggressive phenotype of hepatocellular carcinoma. However, increasing evidence highlights the limitations of the Warburg effect, such as high mitochondrial respiration and low glycolysis rates in cancer cells. To explain such contradictory phenomena with regard to the Warburg effect, a metabolic interplay between glycolytic and oxidative cells was proposed, i.e., the "reverse Warburg effect". Aerobic glycolysis may also occur in the stromal compartment that surrounds the tumor; thus, the stromal cells feed the cancer cells with lactate and this interaction prevents the creation of an acidic condition in the tumor microenvironment. This concept provides great heterogeneity in tumors, which makes the disease difficult to cure using a single agent. Understanding metabolic flexibility by lactate shuttles offers new perspectives to develop treatments that target the hypoxic tumor microenvironment and overcome the limitations of glycolytic inhibitors.

Methyl jasmonate sensitizes human bladder cancer cells to gambogic acid-induced apoptosis through down-regulation of EZH2 expression by miR-101

BACKGROUND AND PURPOSE

Gambogic acid (GA) and methyl jasmonate (MJ) are increasingly being recognized as novel natural anticancer compounds. Here, we investigated the antitumour effects of GA in combination with MJ on human bladder cancer cells.

EXPERIMENTAL APPROACH

Cell viability was detected by cell counting kit-8 assay. Cell apoptosis was assessed by Hoechst 33258 staining and flow cytometry. Protein levels were determined by immunoblotting and expressions of mRNA and miRNAs by RT-PCR. Differential expressions of a group of downstream genes were identified using microarray analysis.

KEY RESULTS

MJ significantly sensitized bladder cancer cells to GA-induced growth inhibition and apoptosis while sparing normal fibroblasts. MJ enhanced GA-induced activation of caspase-3 and caspase-9, and down-regulated the expression of XIAP. Furthermore, treatment of bladder cancer cells with a combination of GA and MJ induced synergistic inhibition of the enhancer of zeste homologue 2 (EZH2) expression, whereas miR-101 expression was up-regulated. Conversely, knockdown of miR-101 restored this decreased expression of EZH2 and suppressed the inhibitory effect of GA and MJ on the growth of bladder cancer cells. Microarray analysis showed that genes closely associated with bladder cancer development were significantly down-regulated by GA and MJ. In a s.c. xenograft mouse model of human bladder carcinoma, the combination of GA and MJ exerted an increased antitumour effect compared with GA alone.

CONCLUSION AND IMPLICATIONS

MJ sensitizes bladder cancer cells to GA-induced apoptosis by down-regulating the expression of EZH2 induced by miR-101. Thus, the combination of selective anti-cancer agents MJ and GA could provide a novel strategy for treating human bladder cancer.

Methyl jasmonate: putative mechanisms of action on cancer cells cycle, metabolism, and apoptosis

Methyl jasmonate (MJ), an oxylipid that induces defense-related mechanisms in plants, has been shown to be active against cancer cells both in vitro and in vivo, without affecting normal cells. Here we review most of the described MJ activities in an attempt to get an integrated view and better understanding of its multifaceted modes of action. MJ (1) arrests cell cycle, inhibiting cell growth and proliferation, (2) causes cell death through the intrinsic/extrinsic proapoptotic, p53-independent apoptotic, and nonapoptotic (necrosis) pathways, (3) detaches hexokinase from the voltage-dependent anion channel, dissociating glycolytic and mitochondrial functions, decreasing the mitochondrial membrane potential, favoring cytochrome c release and ATP depletion, activating pro-apoptotic, and inactivating antiapoptotic proteins, (4) induces reactive oxygen species mediated responses, (5) stimulates MAPK-stress signaling and redifferentiation in leukemia cells, (6) inhibits overexpressed proinflammatory enzymes in cancer cells such as aldo-keto reductase 1 and 5-lipoxygenase, and (7) inhibits cell migration and shows antiangiogenic and antimetastatic activities. Finally, MJ may act as a chemosensitizer to some chemotherapics helping to overcome drug resistant. The complete lack of toxicity to normal cells and the rapidity by which MJ causes damage to cancer cells turn MJ into a promising anticancer agent that can be used alone or in combination with other agents.

A review (research and patents) on jasmonic acid and its derivatives

In medicinal chemistry there is a growing interest in using small molecules, including plant stress hormones. Jasmonic acid (JA) and its volatile methyl ester (MJ), collectively termed jasmonates, are lipid-derived cyclopentanone compounds that occur ubiquitously and exclusively in the plant kingdom. This review covers the synthesis, usage, and biological activities of JA and its derivatives. A brief overview of the available information on JA and its features is given, followed by a detailed review of JA and its derivatives as drugs and prodrugs; the properties in plants and the synthesis in recent patents are described. This review shows the direction of long-term drug/nutraceutical safety trials and provides insights for future research in this area. Research on JA continues to be of major interest. Recent innovations offer hope for the development of new therapeutics in related fields. It is anticipated that several analogs can be advanced to preclinical and clinical studies.

Cisplatin induces differentiation of breast cancer cells

Breast tumors are heterogeneous including cells with stem cell properties and more differentiated cells. This heterogeneity is reflected into the molecular breast cancer subtypes. Breast cancer stem cells are resistant to chemotherapy, thus recent efforts are focusing on identifying treatments that shift them toward a more differentiated phenotype, making them more susceptible to chemotherapy. We examined whether the drug cisplatin induces differentiation in breast cancer cell lines that represent different breast cancer subtypes. We used three cell lines representing triple-negative breast cancers, BT-549 and MDA-MB-231 (claudin-low), and MDA-MB-468 (basal-like), along with estrogen and progesterone receptor positive MCF-7 cells (luminal). Cisplatin was applied at 2.5, 5, 10, and 20 μM, and cell viability and proliferation were measured using MTS and BrdU assays, respectively. The effect of cisplatin on the cellular hierarchy was examined by flow cytometry, immunofluorescence and qRT-PCR. Cisplatin treatment of 10 and 20 μM reduced cell viability by 36–51% and proliferation capacity by 36–67%. Treatment with cisplatin resulted in 12–67% down-regulation of stem cell markers (CD49f, SSEA4) and 10–130% up-regulation of differentiation markers (CK18, SMA, β-tubulin). At the mRNA level, CD49f was down-regulated whilst β-tubulin was up-regulated in the claudin-low cell lines. SSEA4 protein expression decreased upon cisplatin treatment, but SSEA4 mRNA expression increased indicating a differential regulation of cisplatin at the post-transcriptional level. It is concluded that cisplatin reduces breast cancer cell survival and induces differentiation of stem/progenitor cell subpopulations within breast cancer cell lines. These effects indicate the potential of this drug to target specific chemotherapy-resistant cells within a tumor.

The anti-cancer activities of jasmonates

Jasmonates, plant stress hormones protecting the plant from microbial pathogens and environmental stresses, were also discovered to have toxic activities toward mammalian cancer cells. Methyl jasmonate (MJ) was found to be the most active anti-cancer derivate among natural jasmonates, exhibiting a specific cell death-induction effect toward several cancer cells. Since that discovery of jasmonates-inducing cancer cell death, the molecular mechanism of action of jasmonates leading to cell death was deciphered. Moreover, in addition to the direct effects of MJ on cancer cell death, it was found to deregulate several genes and affect various intracellular factors and cellular processes, such as sensitization of apoptotic cell death induced by TRAIL, cancer cell migration attenuation, cell cycle arrest, and differentiation. This mini-review summarizes over a decade of research of jasmonates as anti-cancer agents.

Algae extracts and methyl jasmonate anti-cancer activities in prostate cancer: choreographers of 'the dance macabre'

There is an overwhelmingly increasing trend of analysis of naturally occurring ingredients in treatment of prostate cancer. Substantial fraction of information has been added that highlights activity at various levels and steps of deregulated cellular proliferation, metastasis and apoptosis. Among such ingredients, algae extracts and jasmonates are documented to have anti-cancer activity in vitro and in vivo and induce growth inhibition in cancer cells, while leaving the non-transformed cells intact. In this short review we outline systematically, how these ingredients predispose prostate cancer cells to undergo apoptosis.