Cytotoxic potential and metabolomic profiling of alkaloid rich fraction of Tylophora indica leaves.

Tylophora indica (Burm f.) Merrill, belong to family Asclepiadaceae, is considered to be a natural remedy with high medicinal benefits. The objective of this work is to assess the metabolomic profile of T. indica leaves enriched in alkaloids, as well as to evaluate the in vitro cytotoxicity of these leaves using the MTT assay on human breast MCF-7 and liver HepG2 cancer cell lines. Dried leaves of T. indica were extracted by sonication, using methanol containing 2 % (v/v) of acetic acid and obtained fraction was characterized by HPTLC and UPLC-MS. The UPLC-MS study yielded a preliminary identification of 32 metabolites, with tylophorine, tylophorine B, tylophorinine, and tylophorinidine being the predominant metabolites. The cytotoxicity of the extract of T. indica was evaluated on HepG2 and MCF-7 cell lines, yielding inhibitory concentration (IC50) values of 75.71 µg/mL and 69.60 µg/mL, respectively. Data suggested that the phytochemical screening clearly showed presence of numerous secondary metabolites with moderate cytotoxic efficacy. In conclusion, the future prospects of T. indica appear promising for the advancement of phytopharmaceutical-based anticancer medications, as well as for the design of contemporary pharmaceuticals in the field of cancer chemotherapy.

Phenanthroindolizidine Alkaloids Isolated from Tylophora ovata as Potent Inhibitors of Inflammation, Spheroid Growth, and Invasion of Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC), representing the most aggressive form of breast cancer with currently no targeted therapy available, is characterized by an inflammatory and hypoxic tumor microenvironment. To date, a broad spectrum of anti-tumor activities has been reported for phenanthroindolizidine alkaloids (PAs), however, their mode of action in TNBC remains elusive. Thus, we investigated six naturally occurring PAs extracted from the plant Tylophora ovata: O-methyltylophorinidine (1) and its five derivatives tylophorinidine (2), tylophoridicine E (3), 2-demethoxytylophorine (4), tylophoridicine D (5), and anhydrodehydrotylophorinidine (6). In comparison to natural (1) and for more-in depth studies, we also utilized a sample of synthetic O-methyltylophorinidine (1s). Our results indicate a remarkably effective blockade of nuclear factor kappa B (NFκB) within 2 h for compounds (1) and (1s) (IC50 = 17.1 ± 2.0 nM and 3.3 ± 0.2 nM) that is different from its effect on cell viability within 24 h (IC50 = 13.6 ± 0.4 nM and 4.2 ± 1 nM). Furthermore, NFκB inhibition data for the additional five analogues indicate a structure-activity relationship (SAR). Mechanistically, NFκB is significantly blocked through the stabilization of its inhibitor protein kappa B alpha (IκBα) under normoxic as well as hypoxic conditions. To better mimic the TNBC microenvironment in vitro, we established a 3D co-culture by combining the human TNBC cell line MDA-MB-231 with primary murine cancer-associated fibroblasts (CAF) and type I collagen. Compound (1) demonstrates superiority against the therapeutic gold standard paclitaxel by diminishing spheroid growth by 40% at 100 nM. The anti-proliferative effect of (1s) is distinct from paclitaxel in that it arrests the cell cycle at the G0/G1 state, thereby mediating a time-dependent delay in cell cycle progression. Furthermore, (1s) inhibited invasion of TNBC monoculture spheroids into a matrigel®-based environment at 10 nM. In conclusion, PAs serve as promising agents with presumably multiple target sites to combat inflammatory and hypoxia-driven cancer, such as TNBC, with a different mode of action than the currently applied chemotherapeutic drugs.

Tylophora hirsuta (Wall.) Extracts Ameliorate Diabetes Associated with Inflammation in Alloxan-induced Diabetic Rats.

BACKGROUND: Tylophora hirsuta (Wall) has long been used as traditional medicine for the treatment of diabetes. The current study is designed to evaluate the anti-diabetic and anti-inflammatory activity of different extracts of aerial parts of Tylophora hirsuta. METHODS: Sequential maceration was conducted to obtain extracts. Total phenolic contents were determined by the Folin-Ciocalteau method. The anti-oxidant activity was assessed by DPPH free radical scavenging assay. The extracts were tested for its inhibitory activity against α-amylase in-vitro. In-vivo anti-diabetic assay was conducted using alloxan-induced diabetic model and OGTT was conducted on normal rats. ELISA was used to determine the pro-inflammatory cytokines (TNF-α and IL-6). The polyphenolic composition of the extract was analyzed using an HPLC system. RESULTS: Aqueous extract exhibited highest total phenolic contents (985.24± 3.82 mg GAE/100 g DW), antioxidant activity (IC50 = 786.70 ± 5.23 µg/mL), and alpha-amylase inhibition (IC50 =352.8 µg/mL). The aqueous extract of Tylophora hirsuta showed remarkable in-vivo anti-diabetic activity. Results were compared with standard drug glibenclamide. Alloxan induced diabetic mediated alterations in liver function enzymes, renal function determinants, and lipid parameters were significantly restored in aqueous extract treated diabetic rats. A significant reduction in pro-inflammatory cytokines (p<0.001) was observed when compared to the control group. HPLC analysis confirms the presence of quercetin, gallic acid, cinnamic acid, and p-coumaric acid. CONCLUSION: These results showed that Tylophora hirsuta possesses strong anti-diabetic and anti-inflammatory potentials and justify its folklore use for the management of diabetes.

Tylophora indica (Burm. f.) merr: An insight into phytochemistry and pharmacology.

ETHNOPHARMACOLOGICAL RELEVANCE: Tylophora indica (Burm. f.) Merr. commonly known as ananthamool is a climbing perennial plant which is widely used in Indian traditional medicine. T. indica exhibits diverse range of pharmacological activities viz. antiasthmatic, antidiarrheal, anticancer, antiarthritic, antiepileptic, anti-inflammatory etc. AIM OF THE STUDY: Present review aims to grant an up-to-date insight into the botany, ethnopharmacology, phytochemistry, pharmacology and toxicology of T. indica, exploring its future research and opportunities. MATERIAL AND METHODS: Comprehensive information regarding T. indica was collected using the keywords Tylophora indica or Indian ipecac or ananthamool in various electronic databases ACS, Google Scholar, Pubmed, Science Direct, SciFinder, Web of Science, Springer Link and Wiley. In addition, some books and book chapters were also consulted. RESULTS: T. indica has been traditionally used in India, Bangladesh and Sri Lanka in the form of various preparations like powder, decoction, pulp, paste and extract alone or in combination with other herbs against various ailments like skin disorders, inflammation, cough, asthma, diarrhea, cancer, microbial infections etc. In vitro and in vivo pharmacological studies on T. indica revealed its potential as antiasthmatic, antiallergic, anti-inflammatory, anticancer, antimicrobial, antioxidant, antidiarrheal agent etc. A diverse range of phytochemical constituents have been isolated and identified from T. indica namely alkaloids (Tylophorine, Tylophorinine, Tylophorinidine), flavonoids (Kaempferol & Quercetin) terpenoids (α-Amyrin & ß-Amyrin) and sterols (ß-sitosetrol). Amongst which phenanthroindolizidine alkaloids isolated from roots and leaves are largely explored and considered to be the most active constituent of plant. CONCLUSION: Present review provides an insight into botany, ethnopharmacology, phytochemistry, pharmacology and toxicology of T. indica. As an important traditional Indian medicine, few ethnobotanicals use of T. indica have been supported by modern pharmacological studies, especially in asthma, cancer and inflammation. Among compounds from various phytochemical classes, phenanthoindolizidine alkaloids namely tylophorine and tylophorinidine alkaloids have been considered as bioactive components of the plant and widely investigated. However, further identification, isolation and quantification employing some advanced hyphenated techniques viz. LC-MS/MS, LC-NMR to discover new pharmacologically active phytoconstituents in the management of different diseases. Several investigators have highlighted possible therapeutic roles of T. indica extracts and isolated compounds. Moreover, information about various aspects of T. indica pertaining to phytochemistry, toxicology and quality control are still unresolved. Further in-depth studies are required to discover key features viz. structure activity relationships, mode of action, safety and toxicity and therapeutic potentials T. indica in clinical settings.

Design, Synthesis and in Vitro Evaluation of Tylophorine Derivatives as Possible Antitumor Agents.

Structural simplification and modification of natural products are always very important resources to antitumor drugs. By introducing various aminomethyl groups and amide groups into the phenanthrene ring of tylophorine, a novel series of tylophorine derivatives have been designed and synthesized, and their antiproliferative activities against MCF-7, A549 and HepG-2 cells have been evaluated, too. The results indicated that most of the prepared compounds exhibited good antitumor activities. Especially, one compound with an {ethyl[2-(morpholin-4-yl)ethyl]amino}methyl group at the side chain exhibited the most significant cytotoxic effects.

5-Oxo-1-[(2,3,6,7-tetramethoxy-9-phenanthrenyl)methyl]-L-proline Inhibits Hepatitis C Virus Entry.

Hepatitis C virus (HCV) is the major causative agent of chronic liver diseases, including liver cirrhosis and hepatocellular carcinoma. The recent development of highly effective direct-acting antivirals (DAAs) has revolutionized the treatment of HCV patients. However, these DAAs are exorbitantly expensive for the majority of HCV patients worldwide. Moreover, these drugs still show genotypic difference in cure rate and have some resistant-associated variants. Tylophorine, a natural compound derived from Tylophora indica plants, is known to have anti-inflammatory and anti-cancerous growth activities. In the present study, we showed that two tylophorine intermediates, 5-Oxo-1-[(2,3,6,7-tetramethoxy-9-phenanthrenyl) methyl]-L-proline (O859585) and 2,3,6,7-tetramethoxy-9-phenanthrenecarboxylic acid (T298875), displayed anti-HCV activity with an EC50 of 38.25 µM for T298875 and 29.11~35.3 µM for O859585 in various HCV genotypes. We demonstrated that O859585 efficiently blocked HCV attachment by neutralizing free viral particles without affecting other stages of the HCV life cycle and interferon stimulation. O859585 interrupted binding between HCV E2 and CD81. Of note, co-treatment of O859585 with either interferon alpha (IFNα) or sofosbuvir exerted either an additive or synergistic antiviral activity in HCV-infected cells with no measurable effect on cell viability. Most importantly, O859585 in combination with IFNα and sofosbuvir exhibited synergistic effects on anti-HCV activity in primary human hepatocytes. Collectively, these data suggest that O859585 may be a novel antiviral agent for HCV therapy.

The Potential Impacts of Tylophora Alkaloids and their Derivatives in Modulating Inflammation, Viral Infections, and Cancer.

Cancer chemotherapies or antitumor agents mainly remain the backbone of current treatment based on killing the rapidly dividing cancer cell such as tylophora alkaloids and their analogues which have also demonstrated anticancer potential through diverse biological pathways including regulation of the immune system. The introduction of durable clinically effective monoclonal antibodies, however, unmasked a new era of cancer immunotherapies. Therefore, the understanding of cancer pathogenesis will provide new possible treatment options, including cancer immunotherapy and targeted agents. Combining cytotoxic agents and immunotherapies may offer several unique advantages that are complementary to and potentially synergistic with biologic modalities. Herein, we highlight the dynamic mechanism of action of immune modulation in cancer and the immunological aspects of the orally active antitumor agents tylophora alkaloids and their analogues. We also suggest that future cancer treatments will rely on the development of combining tumor-targeted agents and biologic immunotherapies.

[Investigations on secondary metabolites of endophyte Diaporthe sp. hosted in Tylophora ovata].

One new compound (2S, 3S)-2,3-dihydroxybutyl 2-hydroxy-3,5,6-trimethylbenzoate (1) and six known compounds xylariphthalide A (2), convolvulol (3), cis-4-hydroxy-6-deoxytalone (4), phomoxydienes B (5), 5,6-dihydroxy-2,3,6-trimethylcyclohex-2-enone (6), trans-cyclo-(D-tryptophanyl-L-tyrosyl) (7) were isolated from Diaporthe sp., an endophytic fungus hosted in the leaves of the toxic Chinese folk medicine Tylophora ouata, using the combination methods of silica gel column chromatography, medium-pressure ODS column chromatography and RP-preparative HPLC. The structure of compound 1 was elucidated by NMR and MS data analyses. The absolute configurations were established according to the ¹H-NMR data and exciton chirality method. Compound 1 inhibited the activation of human lung fibroblasts MRC-5 cells by 64.0% at 10 µmol·L⁻¹. The MTT assay showed that compounds 2 and 4 displayed cytotoxic activity against human tumor cell lines BGC-823 cells with IC50 values of 1.5 and 8.6 µmol·L⁻¹, respectively.

Dothiorelone derivatives from an endophyte Diaporthe pseudomangiferaea inhibit the activation of human lung fibroblasts MRC-5 cells.

Nine new compounds (1-6 and 16-18) and nine known compounds (7-15) were isolated from Diaporthe pseudomangiferaea, an endophytic fungus obtained from the leaves of the toxic Chinese folk medicine Tylophora ouata. Their structures were elucidated by NMR spectroscopy and MS spectrometry analyses. The absolute configurations were established according to the specific rotation or electron circular dichroism method. Compounds 1, 4, 9, 11, 14 and 15 inhibited the TFG-ß induced activation of human lung fibroblasts MRC-5 cells by 17.4%, 59.2%, 62.9%, 41.1%, 32.9% and 52.1% at 10 µM, respectively, while positive control pirfenidone showed 53.2% inhibition rate at 1 mM. The MTT assay showed that compounds 13 and 14 displayed cytotoxicity against BGC-823 cells, with IC50 values of 8.1 and 4.4 µM, respectively.

Screening of promising chemotherapeutic candidates from plants against human adult T-cell leukemia/lymphoma (IV): phenanthroindolizidine alkaloids from Tylophora tanakae leaves.

Adult T-cell leukemia/lymphoma (ATL) is a malignancy of mature peripheral T lymphocytes caused by human T-cell lymphotropic virus type 1 (HTLV-1). There are an estimated 5 million to 20 million HTLV-1-infected individuals worldwide; their lifetime risk of developing ATL is 3-5 %, and high HTLV-1 proviral loads have been shown to be an independent risk factor. Although conventional chemotherapeutic regimens used against other malignant lymphomas have been administered to ATL patients, the prognosis is often poor. In previous studies, we screened 459 extracts from 344 plants to isolate components exhibiting antiproliferative activity against HTLV-1-infected T-cell lines (MT-1 and MT-2). In our continuing search for potential anti-HTLV-1 natural products, 15 extracts of Asclepiadaceae plants were further tested against MT-1 and MT-2 cells. The MeOH extract of aerial parts of Tylophora tanakae showed antiproliferative activity. Activity-guided fractionation resulted in the isolation of 6 phenanthroindolizidine alkaloids (including a new compound), and we examined their antiproliferative activity against MT-1 and MT-2 cells. The EC50 value of some of the alkaloids was in the low nanomolar range, comparable to that of the clinically used antineoplastic drug doxorubicin. Structure-activity relationship analyses suggested that a 14ß-hydroxy moiety is essential for activity against HTLV-1-infected T cells. In contrast, the presence of a 2-methoxy moiety, a 7-methoxy moiety, or an N-oxide moiety appears to reduce the potency of the antiproliferative activity against HTLV-1-infected T cells.

Tylophorine, a phenanthraindolizidine alkaloid isolated from Tylophora indica exerts antiangiogenic and antitumor activity by targeting vascular endothelial growth factor receptor 2-mediated angiogenesis.

BACKGROUND: Anti-angiogenesis targeting VEGFR2 has been considered as an important strategy for cancer therapy. Tylophorine is known to possess anti-inflammatory and antitumor activity, but its roles in tumor angiogenesis, the key step involved in tumor growth and metastasis, and the involved molecular mechanism is still unknown. Therefore, we examined its anti-angiogenic effects and mechanisms in vitro and in vivo. METHODS: We used tylophorine and analyzed its inhibitory effects on human umbilical vein endothelial cells (HUVEC) in vitro and Ehrlich ascites carcinoma (EAC) tumor in vivo. RESULTS: Tylophorine significantly inhibited a series of VEGF-induced angiogenesis processes including proliferation, migration, and tube formation of endothelial cells. Besides, it directly inhibited VEGFR2 tyrosine kinase activity and its downstream signaling pathways including Akt, Erk and ROS in endothelial cells. Using HUVECs we demonstrated that tylophorine inhibited VEGF-stimulated inflammatory responses including IL-6, IL-8, TNF-α, IFN-γ, MMP-2 and NO secretion. Tylophorine significantly inhibited neovascularization in sponge implant angiogenesis assay and also inhibited tumor angiogenesis and tumor growth in vivo. Molecular docking simulation indicated that tylophorine could form hydrogen bonds and aromatic interactions within the ATP-binding region of the VEGFR2 kinase unit. CONCLUSION: Tylophorine exerts anti-angiogenesis effects via VEGFR2 signaling pathway thus, may be a viable drug candidate in anti-angiogenesis and anti-cancer therapies.

c-Jun-mediated anticancer mechanisms of tylophorine.

Tylophorine, a phenanthroindolizidine alkaloid, is the major medicinal constituent of herb Tylophora indica. Tylophorine treatment increased the accumulation of c-Jun protein, a component of activator protein 1 (AP1), in carcinoma cells. An in vitro kinase assay revealed that the resultant c-Jun phosphorylation was primarily mediated via activated c-Jun N-terminal protein kinase (JNK). Moreover, flow cytometry indicated that ectopically overexpressed c-Jun in conjunction with tylophorine significantly increased the number of carcinoma cells that were arrested at the G1 phase. The tylophorine-mediated downregulation of cyclin A2 protein levels is known to be involved in the primary G1 arrest. Chromatin immunoprecipitation and reporter assays revealed that tylophorine enhanced the c-Jun downregulation of the cyclin A2 promoter activity upon increased binding of c-Jun to the deregulation AP1 site and decreased binding to the upregulation activating transcription factor (ATF) site in the cyclin A2 promoter, thereby reducing cyclin A2 expression. Further, biochemical studies using pharmacological inhibitors and RNA silencing approaches demonstrated that tylophorine-mediated elevation of the c-Jun protein level occurs primarily via two discrete prolonged signaling pathways: (i) the NF-κB/PKCδ_(MKK4)_JNK cascade, which phosphorylates c-Jun and increases its stability by slowing its ubiquitination, and (ii) the PI3K_PDK1_PP2A_eEF2 cascade, which sustains eukaryotic elongation factor 2 (eEF2) activity and thus c-Jun protein translation. To the best of our knowledge, this report is the first to demonstrate the involvement of c-Jun in the anticancer activity of tylophorine and the release of c-Jun translation from a global translational blockade via the PI3K_PDK1_eEF2 signaling cascade.

Interaction studies of an anticancer alkaloid, (+)-(13aS)-deoxytylophorinine, with calf thymus DNA and four repeated double-helical DNAs.

BACKGROUND: Phenanthroindolizidine alkaloids are a family of plant-derived compounds with significant antineoplastic activity. The specific biomolecular targets of these alkaloids have not yet been clearly identified. (+)-(13aS)-deoxytylophorinine is a new phenanthroindolizidine alkaloid originally extracted from the roots of Tylophora atrofolliculata and Tylophora ovata in our institute. (+)-(13aS)-deoxytylophorinine exerts both in vitro and in vivoanticancer activities. METHODS: The in vivo anticancer effects and toxicity of this compound were investigated in mice, and interactions between this compound and double-helical DNA sequences were studied in detail with circular dichroic spectroscopy and fluorescence spectroscopy. Viscosity measurements were applied to check the interactive mode between this compound and DNA. RESULTS: Potent anticancer effects were observed in vivo. Also, concentration-dependent interactions were observed and this compound seemed to interact in a sequence-specific manner with AT-repeated sequences of double-helical DNA. Such interactions were proved to be intercalating by viscosity measurements. CONCLUSIONS: Anticancer alkaloid (+)-(13aS)-deoxytylophorinine can have sequence-specific interactions with DNA in an intercalating manner.

Isolation and biological activities of phenanthroindolizidine and septicine alkaloids from the Formosan Tylophora ovata.

An investigation of alkaloids present in the leaves and stems of Tylophora ovata led to the isolation of two new septicine alkaloids and one new phenanthroindolizidine alkaloid, tylophovatines A, B, C (1, 2, and 5), respectively, together with two known septicine and six known phenanthroindolizidine alkaloids. The structures of the new alkaloids 1, 2, and 5 were established by means of spectroscopic analyses. These eleven alkaloids show in vitro anti-inflammatory activities with IC50 values ranging from 84 nM to 20.6 µM through their suppression of nitric oxide production in RAW264.7 cells stimulated by lipopolysaccharide and interferon-γ. Moreover, these substances display growth inhibition in HONE-1, NUGC-3, HepG2, SF-268, MCF-7, and NCI-H460 cancer cell lines, with GI50 values ranging from 4 nM to 24.2 µM. In addition, tylophovatine C (5) and 13a(S)-(+)-tylophorine (7) were found to exhibit potent in vivo anti-inflammation activities in a rat paw edema model. Finally, structure­activity relationships were probed by using the isolated phenanthroindolizidines and septicines. Phenanthroindolizidines are suggested to be divided into cytotoxic agents (e.g., 10 and 11) and anti-inflammation based anticancer agents (e.g., 5­9).

Anticancer effect and neurotoxicity of S-(+)-deoxytylophorinidine, a new phenanthroindolizidine alkaloid that interacts with nucleic acids.

Phenanthroindolizidine alkaloids are a family of plant-derived compounds with significant antineoplastic activity as well as other effects like antiamebicidal, antiviral, and anti-inflammatory activities. The specific biomolecular targets of these compounds have not yet been clearly identified. S-(+)-Deoxytylophorinidine (CAT) is a new phenanthroindolizidine alkaloid, originally extracted from the roots of Tylophora atrofolliculata and Tylophora ovata. Potent anticancer activity was observed in vitro and in vivo. Neurotoxicity of CAT was also studied and it was far less serious than that of vinblastine. Interactions between this compound and DNA had been studied in detail in our laboratory previously, and we further studied its interactions with RNA.

Structural analogs of tylophora alkaloids may not be functional analogs.

Phenanthroindolizidine-based tylophora alkaloids have been reported to have potential antitumor, anti-immuno and, anti-inflammatory activity. The structure-activity relationships of a series of tylophora alkaloids were studied to guide future drug design. Our results indicate that although these compounds are structural analogs, their potency of cytotoxicity, selectivity against NF-kappaB signaling pathway, and their inhibitory effects against protein and nucleic acid synthesis are different. Because they do not have an identical spectrum of targets, the studied compounds are structural, but may not be functional analogs.

The potential role of natural agents in treatment of airway inflammation.

Obstructive airway diseases including asthma, chronic obstructive pulmonary disease and cystic fibrosis present with dyspnea and variety of other symptoms. Physiologically, they are characterized by maximal expiratory flow limitation and pathologically, by inflammation of the airways and the lung parenchyma. Inflammation plays a major role in the gradual worsening of the lung function resulting in worsening symptoms. For many years, scientists focused their efforts in identifying various pathways involved in the chronic inflammation present in these diseases. Further, studies are underway to identify various molecular targets in these pathways for the purpose of developing novel therapeutic agents. Natural agents have been used for thousands of years in various cultures for the treatment of several medical conditions and have mostly proven to be safe. Recent in vivo and in vitro studies show potential anti-inflammatory role for some of the existing natural agents. This review provides an overview of the literature related to the anti-inflammatory effects of some of the natural agents which have potential value in the treatment of inflammatory lung diseases.

Cytotoxic alkaloids from the roots of Tylophora atrofolliculata.

Four new phenanthroindolizidine alkaloids, tylophoridicines C-F, together with three known ones, R-(+)-deoxytylophorinidine, tylophorinine and tylophorinidine, were isolated from the roots of Tylophora atrofolliculata. The structures were determined on the basis of spectral evidence. These alkaloids exhibited cytotoxic activity in vitro on HCT-8 cell (with IC50 values in the range 0.083 to 18.99 microM) and KB cell (in the range 3.56 to 18.22 microM) lines.

Induction of apoptosis in a human erythroleukemic cell line K562 by tylophora alkaloids involves release of cytochrome c and activation of caspase 3.

Tylophora alkaloids are plant products known for their antiasthamatic and antiproliferative activities. The underlying cellular changes resulting from inhibition of proliferation were investigated. Tylophora alkaloids induced apoptosis in K562 cells with characteristic apoptotic features like nuclear condensation, apoptotic body formation, flipping of membrane phosphatidylserine, activation of caspase 3 and release of mitochondrial cytochrome c. These studies suggest that the Tylophora alkaloids, in addition to their antiproliferative effects also induce apoptosis in erythroleukemic cells. These observations imply that Tylophora alkaloids could be useful molecules for their antiproliferative activity and for induction of apoptosis in tumor cells.