Antiproliferative and Antiproteolytic activity of Pentoxifylline in cultures of B16F10 Melanoma cells

Pentoxifylline and Norcantharidin Modify p62 Expression in 2D and 3D Cultures of B16F1 Cells

Three-dimensional cell cultures have improved the evaluation of drugs for cancer therapy, due to their high similarity to solid tumors. In melanoma, autophagy appears to show a dual role depending on the progression of the disease. p62 protein has been proposed for the evaluation of autophagic flux since its expression is an indicator of the state of autophagy. Pentoxifylline (PTX) and Norcantharidin (NCTD) are drugs that have been shown to possess anticancer effects. In this work, we used B16F1 mouse melanoma cells in two-dimensional (2D) monolayer cultures and three-dimensional (3D) spheroids to test the effect of PTX and NCTD over the p62 expression. We analyzed the effect on p62 expression through Western blot and immunofluorescence assays. Our results indicate that PTX decreases p62 expression in both cell culture models, while Norcantharidin increases its expression in 3D cultures at 24 h. Therefore, these drugs could have a potential therapeutic use for the regulation of autophagy in melanoma, depending on the state of evolution of the disease.

Pentoxifylline Inhibits TNF-α/TGF-β1-Induced Epithelial-Mesenchymal Transition via Suppressing the NF-κB Pathway and SERPINE1 Expression in CaSki Cells

Cervical cancer (CC) is one of the most common and deadly types of female cancer worldwide. Late diagnosis in CC increases the risk of tumor cells spreading to distant organs (metastasis). The epithelial-mesenchymal transition (EMT) is a fundamental process of cancer metastasis. Inflammation can lead to tumor progression, EMT induction, and metastasis. The inflammatory microenvironment is a potent inducer of EMT; inflammatory cytokines such as Tumor Necrosis Factor-alpha (TNF-α) and Transforming growth factor-beta (TGF-β1) activate transcriptional factors such as STAT3, Snail, Smad, and the Nuclear Factor kappa light-chain-enhancer of activated beta cells (NF-κΒ), which drive EMT. Anti-inflammatory compounds may be an option in the disruption of EMT. PenToXifylline (PTX) possesses potent anti-inflammatory effects by inhibiting NF-κB activity. In addition, PTX exerts an anti-fibrotic effect by decreasing Smad2/3/4. We hypothesize that PTX could exert anti-EMT effects. CaSki human cervical tumor cells were exposed to TNF-α 10 ng/mL and TGF-β1 alone or in combination for 5 days. Our results revealed that TNF-α and TGF-β1 induced N-cadherin and Vimentin, confirming the induction of EMT. Furthermore, the combination of cytokines synergized the expression of mesenchymal proteins, enhanced IκBα and p65 phosphorylation, and upregulated Serpin family E member 1 (SERPINE1) mRNA. PTX pretreatment prior to the addition of TNF-α and TGF-β1 significantly reduced N-cadherin and Vimentin levels. To our knowledge, this is the first time that this effect of PTX has been reported. Additionally, PTX reduced the phosphorylation of IκB-α and p65 and significantly decreased SERPINE1 expression, cell proliferation, migration, and invasion. In conclusion, PTX may counteract EMT in cervical cancer cells by decreasing the NF-κB and SERPINE1.

Topical Tacrolimus Progylcosomes Nano-Vesicles As a Potential Therapy for Experimental Dry Eye Syndrome

The present work aimed to evaluate the efficacy of topical tacrolimus (0.01%) loaded propylene glycol (PG) modified nano-vesicles (Proglycosomes Nano-vesicles, PNVs) for the treatment of experimental dry eye syndrome (DES) in rabbits. DES was induced by topical application of atropine (1.0%) and benzalkonium chloride (0.1%) aqueous solution. PNVs treatment (PNV group) was compared with tacrolimus solution 0.01% (TAC group) and untreated group and healthy group were used as controls. PNV treated animals showed improved clinical performance with marked increase in tear production and tear break-up time (TBUT). Further, PNVs also subside ocular inflammation as evident from absence of matrix metalloprotenaise-9 and normal ocular surface temperature (32.3 ± 0.34 °C). Additionally, PNVs have positive effect on ocular and epithelial damage observed through low ocular surface staining score and improved globlet cell density. The PNV treatment was found to more effectively compared to TAC solution and most of the parameters were close to those of healthy animals. In conclusion, tacrolimus PNV formulation (0.01%) could be a potential therapy for treatment of dry eye syndrome.

Ligand Decorated Primaquine Loaded Nanocarriers for Liver Targeting for Triggered Anti-Malarial Activity

OBJECTIVE

The aim of the current research is to formulate a nano delivery system for effective delivery of primaquine for liver targeting to achieve the potential anti-malarial activity. Another objective of current development is to formulate a lactobionic acid conjugated polyphosphazene based nano delivery of primaquine for liver targeting to distinguish anti-malarial activity.

METHOD

The particle size, entrapment efficiency, in-vitro drug release pattern, hepatotoxicity, MTT assay, erythrocyte toxicity assay, histopathology study, HepG2 cell uptake study, anti-- malarial study, and organ-distribution was also carried out to estimate the activity and potential features of a nanoparticle system.

RESULTS

The results obtained from the above analysis justify the efficiency and effectiveness of the system. The NMR studies confirm the conjugation pattern and the TEM represents the spherical morphological features of nanoparticles. The controlled release pattern from the in-vitro release study was observed and found to be 73.25% of drug release in 20 hrs and in the nano-size range (61.6± 1.56 nm) by particle size analysis.SGOT level, SGPT, ALP, and Parasitemia level of optimized drug-loaded PEGylated lactobionic acid conjugated polyphosphazene derivatized nanoparticles (FF) was found to lie in the safe range, showing that the formulation is non-toxic to the liver. Primaquine drug-loaded PEGylated lactobionic acid conjugated polyphosphazene polymeric nanoparticles showed higher cell uptake on HepG2 cell lines as compared to the drug-loaded in PEGylated polyphosphazene polymeric nanoparticles and plain drug.Percentage cell viability of drugloaded PEGylated lactobionic acid conjugated polyphosphazene derivatized nanoparticles was decreased by enhancing the concentration of prepared nanoparticle system accessed by MTT assay.

CONCLUSION

From the studies, it can be concluded that the optimized formulation of drug-loaded PEGylated lactobionic acid conjugated polyphosphazene derivatized nanoparticles showed high liver targeting, least toxicity to the liver, controlled release of the drug, higher anti-malarial activity against hepatocytes at a low dose, more effectiveness, and can be treated as a potential candidate for anti-malarial therapy.

The synthesis of a novel pentoxifylline derivative with superior human sperm motility enhancement properties

mPTF1 demonstrated lower genotoxicity, higher affinity for PDEs, & reasonable pharmacokinetic, druglikeness & ADMET properties compared to Pentoxifylline.

Formulation and Development of Transferrin Targeted Solid Lipid Nanoparticles for Breast Cancer Therapy

Breast cancer is conventionally treated by surgery, chemotherapy and radiation therapy followed by post operational hormonal therapy. Tamoxifen citrate is a best option to treat breast cancer because its selective estrogen receptor modulation activity. Owing to its antiestrogenic action on breast as well as uterine cells, Tamoxifen citrate shows uterine toxicity. The dose 20 mg per day of Tamoxifen citrate required to show therapeutic effect causes side effects and toxicity to vital organs such as liver, kidney and uterus. In the present study, transferrin-conjugated solid lipid nanoparticles (SLNs) were successfully prepared to enhance the active targeting of tamoxifen citrate in breast cancer. Developed formulations were evaluated for particle size, surface charge, surface morphology and in vitro dissolution studies. Developed formulations exhibited more cytotoxicity as compared to pure Tamoxifen citrate solution in time as well as concentration dependent manner on human breast cancer MCF-7 cells. Further, cell uptake and flow cytometry studies confirmed the qualitative uptake of developed D-SLN and SMD-SLN by human breast cancer MCF-7 cells. Overall, proposed study highlights that transferrin engineered nanocarriers could enhance the therapeutic response of nanomedicines for breast cancer treatment.

Design, Synthesis, Biological Evaluation and In Silico Studies of Few Novel 2-Substituted Benzothiazole Derivatives as Potential EGFR Inhibitors

Background:

There is a great unmet medical need for new anticancer small molecule therapeutics. Exhaustive literature review suggests that benzothiazole derivatives have good potential to exhibit anticancer activity. Compounds that inhibit the kinase activity of EGFR are of potential interest as new antitumor agent.

Objective:

To design, synthesize and carry out in silico along with biological evaluation of 2- substituted benzothiazole compounds with EGFR inhibitory activity.

Methods:

Benzothiazole derivatives designed from molecular docking method for potential EGFR tyrosine kinase inhibition have been synthesized based on the docking results and characterized. Insilico studies were carried out to understand the mode of EGFR enzyme inhibition by our molecules. As a preliminary study, these compounds were first screened for antioxidant activity and then for anticancer activity against MCF-7 cell lines and A549 cell line.

Results:

Compound B5 showed potent anticancer activity on MCF-7 cell line with IC50 value of 9.7µM and compound B8 showed significant anticancer activity on A549 cell line with IC50 value of 49.7μM in comparison with the standard drug Doxorubicin (IC50 = 1.4µM on MCF-7 and 1.0µM on A549 cell lines). In EGFR inhibitory activity B8 showed maximum activity on A549 cell line by inactivating 69.10% of EGFR phosphorylation and B7 showed maximum activity on MCF-7 cell line by inactivating 41.90% of EGFR phosphorylation in comparison with the reference drug Gefitinib. Molecular dynamics simulation studies suggest that benzothiazole derivative could also bind to allosteric site and inhibit the EGFR enzyme activity.

Conclusion:

Reported compounds have shown potent anticancer activity through EGFR inhibition by possibly binding at allosteric site.

Combination of pentoxifylline and α-galactosylceramide with radiotherapy promotes necro-apoptosis and leukocyte infiltration and reduces the mitosis rate in murine melanoma

Despite the success for the treatment of melanoma such as targeted molecular therapy, the use of such treatments are expensive For this reason, this study was carried out to explore the anti-cancer properties of available drugs that are able to modify the melanoma prognosis. The study was conducted in two phases: Evaluation of pharmacological effects of pentoxifylline (PTX) administered above (60 mg/kg) which is the therapeutic dose that is aimed at reducing the side-effect of radiotherapy, and of α- galactosylceramide (GalCer) administered at 100 μg/kg, as well as their combination using a murine model (BDF1 mice) of melanoma cell line (B16-F1, ATCC). For the radiotherapy phase, 9 Gy was applied in the tumor area, before (3 days), during (30 min) and after (3 days) the PTX + GalCer treatment. In both study phases, the mitosis rate, leukocyte infiltration and necro-apoptosis were assessed using histological and immunohistochemical approach and tumor volume evaluation as biomarkers. All treatments showed good prognosis results estimated as reduction of mitosis rate (PTX + GalCer after radiotherapy and GalCer), increased leukocyte infiltrate (PTX + GalCer after radiotherapy and GalCer) and necro-apoptosis augmentation (PTX + GalCer after radiotherapy and radiotherapy control). Nevertheless, a lower development of tumor volume was found in GalCer treatment. In this way, it is possible to suggest that the integrated treatment with immuno-stimulators such as GalCer, plus drug used for peripheral vascular disease (PTX) after radiotherapy is probably an alternative for controlling aggressive melanoma in murine model.

MicroRNA-184 Promotes Proliferation and Inhibits Apoptosis in HaCaT Cells: An In Vitro Study

BACKGROUND This study aimed to investigate the role of miR-184 in the proliferation and apoptosis of keratinocyte (HaCaT cells). MATERIAL AND METHODS HaCaT cells were cultured in a growth medium. The miR-184 was transfected with siRNA, then cell viability and apoptosis were assayed by MTT and flow cytometry, respectively. The colony-forming efficacy of HaCaT cells were detected as well. mRNA expressions of basic fibroblast growth factor (bFGF) and transforming growth factor (TGF)-β1 were measured with RT-PCR. The expressions of apoptosis-related proteins caspase-3 and Bcl-x in HaCaT cells were determined by Western blot. RESULTS After miR-184 was transfected with siRNA, cell viability and colony forming ability decreased significantly, and apoptosis was significantly increased. The expressions of growth factors TGF-β1 and bFGF mRNAs, as well as apoptosis-related proteins Bcl-x, in HaCaT cells declined significantly after miR-184 was transfected with siRNA. In addition, the expression of pro-apoptotic protein caspase-3 increased significantly. CONCLUSIONS Our results suggest distinct roles of miR-184 during the growth, proliferation, and apoptosis of keratinocytes.

Pentoxifylline Inhibits WNT Signalling in β-Cateninhigh Patient-Derived Melanoma Cell Populations

Background

The heterogeneity of melanoma needs to be addressed and combination therapies seem to be necessary to overcome intrinsic and acquired resistance to newly developed immunotherapies and targeted therapies. Although the role of WNT/β-catenin pathway in melanoma was early demonstrated, its contribution to the lack of the melanoma patient response to treatment was only recently recognized. Using patient-derived melanoma cell populations, we investigated the influence of pentoxifylline on melanoma cells with either high or low expression of β-catenin.

Findings

Our results indicate that pentoxifylline inhibits the activity of the canonical WNT pathway in melanoma cell populations with high basal activity of this signalling. This is supported by lowered overall activity of transcription factors TCF/LEF and reduced nuclear localisation of active β-catenin. Moreover, treatment of β-catenin^high melanoma cell populations with pentoxifylline induces downregulation of genes that are targets of the WNT/β-catenin pathway including connective tissue growth factor (CTGF) and microphthalmia-associated transcription factor (MITF-M), a melanocyte- and melanoma cell-specific regulator.

Conclusions

These results suggest that pentoxifylline, a drug approved by the FDA in the treatment of peripheral arterial disease, might be tested in a subset of melanoma patients with elevated activity of β-catenin. This pharmaceutical might be tested as an adjuvant drug in combination therapies when the response to immunotherapy is prevented by high activity of the WNT/β-catenin pathway.

Cytotoxic activity of Macrosolen parasiticus (L.) Danser on the growth of breast cancer cell line (MCF-7)

Background:

Macrosolen parasiticus (L.) Danser belonging to Loranthaceaea (mistletoe family) is a parasitic plant that grows on different host plants such as mango, jack fruit, peepal, neem tree, etc., This study was aimed to investigate the anti-cancer activity of methanolic and aqueous extract of stem of M. parasiticus.

Objectives:

To investigate the in vitro cytotoxic potential of the methanolic and aqueous extracts from stems of M. parasiticus against MCF-7 breast cancer cells by brine shrimp lethality (BSL) bioassay, MTT assay and sulforhodamine B (SRB) assay.

Materials and Methods:

The extracts were tested in human breast cancer cell lines in vitro for percentage cytotoxicity, apoptosis by acridine orange/ethidium bromide staining, LD₅₀ and IC₅₀ values after treatment with M. parasiticus extracts.

Results:

In BSL bioassay, aqueous extract showed more significant (P < 0.01) cytotoxicity with LD₅₀ 82.79 ± 2.67 μg/mL as compared to methanolic extract with LD₅₀ 125 ± 3.04 μg/mL. The methanolic extract of M. parasiticus showed IC₅₀ 97.33 ± 3.75 μg/mL (MTT) (P < 0.05) and 94.58 ± 3.84 μg/mL (SRB) (P < 0.01) assays against MCF-7. The aqueous extract of M. parasiticus demonstrated higher activity with IC₅₀ 59.33 ± 3.3 μg/mL (MTT) (P < 0.01) and 51.9 ± 1.87 μg/mL (SRB)(P < 0.01) assays, after 48 h of exposure and thus showed significant dose-dependent cytotoxic activity.

Conclusion:

The finding demonstrated that both extracts of M. parasiticus showed significant cytotoxic activity, however aqueous extract demonstrated higher activity against MCF-7 breast cancer cells.

Evaluation of anti-metastatic potential of Cisplatin polymeric nanocarriers on B16F10 melanoma cells

Nanoparticles are being increasingly used in the field of cancer treatment due to their unique properties and advantages. The aim of the present research work was to prepare and characterize a polymeric albumin nanosystem for Cisplatin and evaluate its in-vitro efficacy against B16F10 melanoma. The developed nanoparticles were almost spherical in shape with a particle size in the range of 150–300 nm, low polydispersity values and about 80% drug entrapment efficiency. Albumin nanocarriers sustained the release of Cisplatin for more than 48 h, suggesting the reduction in dosing schedule for this drug. The results from in-vitro cell line studies indicated the dose dependent cytotoxic potential of drug loaded albumin nanoparticles, their potential to inhibit cell proliferation and induce morphological changes. In addition, these nanoparticles exhibited superiority to Cisplatin in hampering the cell migration. Developed nanoparticles caused cell cycle arrest along with time and concentration dependent cellular uptake in B16F10 cell line. These results signify that the prepared Cisplatin albumin nanoparticles could serve as a promising approach for B16F10 melanoma treatment.

Comparative studies to evaluate relative in vitro potency of luteolin in inducing cell cycle arrest and apoptosis in HaCaT and A375 cells

Luteolin is a naturally occurring flavonoid present in many plants with diverse applications in pharmacology. Despite several studies elucidating its significant anti-cancer activity against various cancer cells, the mechanism of action in skin cancer is not well addressed. Hence, we investigated the effects of luteolin in HaCaT (human immortalized keratinocytes) and A375 (human melanoma) cells. The radical scavenging abilities of luteolin were determined spectrophotometrically, prior to a cytotoxic study (XTT assay). Inhibitory effects were assessed by colony formation assay. Further, the capability of luteolin to induce cell cycle arrest and apoptosis were demonstrated by flow cytometry and cellular DNA fragmentation ELISA, respectively. The results revealed that luteolin possesses considerable cytotoxicity against both HaCaT and A375 cells with IC50 values of 37.1 μM and 115.1 μM, respectively. Luteolin also inhibited colony formation and induced apoptosis in a dose and time-dependent manner by disturbing cellular integrity as evident from morphological evaluation by Wright- Giemsa staining. Accumulation of cells in G2/M (0.83-8.14%) phase for HaCaT cells and G0/G1 (60.4-72.6%) phase for A375 cells after 24 h treatment indicated cell cycle arresting potential of this flavonoid. These data suggest that luteolin inhibits cell proliferation and promotes cell cycle arrest and apoptosis in skin cancer cells with possible involvement of programmed cell death, providing a substantial basis for it to be developed into a potent chemopreventive template for skin cancer.

Natural compounds' activity against cancer stem-like or fast-cycling melanoma cells

Background

Accumulating evidence supports the concept that melanoma is highly heterogeneous and sustained by a small subpopulation of melanoma stem-like cells. Those cells are considered as responsible for tumor resistance to therapies. Moreover, melanoma cells are characterized by their high phenotypic plasticity. Consequently, both melanoma stem-like cells and their more differentiated progeny must be eradicated to achieve durable cure. By reevaluating compounds in heterogeneous melanoma populations, it might be possible to select compounds with activity not only against fast-cycling cells but also against cancer stem-like cells. Natural compounds were the focus of the present study.

Methods

We analyzed 120 compounds from The Natural Products Set II to identify compounds active against melanoma populations grown in an anchorage-independent manner and enriched with cells exerting self-renewing capacity. Cell viability, cell cycle arrest, apoptosis, gene expression, clonogenic survival and label-retention were analyzed.

Findings

Several compounds efficiently eradicated cells with clonogenic capacity and nanaomycin A, streptonigrin and toyocamycin were effective at 0.1 µM. Other anti-clonogenic but not highly cytotoxic compounds such as bryostatin 1, siomycin A, illudin M, michellamine B and pentoxifylline markedly reduced the frequency of ABCB5 (ATP-binding cassette, sub-family B, member 5)-positive cells. On the contrary, treatment with maytansine and colchicine selected for cells expressing this transporter. Maytansine, streptonigrin, toyocamycin and colchicine, even if highly cytotoxic, left a small subpopulation of slow-dividing cells unaffected. Compounds selected in the present study differentially altered the expression of melanocyte/melanoma specific microphthalmia-associated transcription factor (MITF) and proto-oncogene c-MYC.

Conclusion

Selected anti-clonogenic compounds might be further investigated as potential adjuvants targeting melanoma stem-like cells in the combined anti-melanoma therapy, whereas selected cytotoxic but not anti-clonogenic compounds, which increased the frequency of ABCB5-positive cells and remained slow-cycling cells unaffected, might be considered as a tool to enrich cultures with cells exhibiting melanoma stem cell characteristics.

Unraveling the cytotoxic potential of Temozolomide loaded into PLGA nanoparticles

Background

Nanotechnology has received great attention since a decade for the treatment of different varieties of cancer. However, there is a limited data available on the cytotoxic potential of Temozolomide (TMZ) formulations. In the current research work, an attempt has been made to understand the anti-metastatic effect of the drug after loading into PLGA nanoparticles against C6 glioma cells.

Nanoparticles were prepared using solvent diffusion method and were characterized for size and morphology. Diffusion of the drug from the nanoparticles was studied by dialysis method. The designed nanoparticles were also assessed for cellular uptake using confocal microscopy and flow cytometry.

Results

PLGA nanoparticles caused a sustained release of the drug and showed a higher cellular uptake. The drug formulations also affected the cellular proliferation and motility.

Conclusion

PLGA coated nanoparticles prolong the activity of the loaded drug while retaining the anti-metastatic activity.

Plasma matrix metalloproteinase activity in horses after intravenous infusion of lipopolysaccharide and treatment with matrix metalloproteinase inhibitors

OBJECTIVE

To establish an in vivo method for matrix metalloproteinase (MMP)-2 and MMP-9 induction in horses via IV administration of lipopolysaccharide (LPS) and to evaluate the ability of doxycycline, oxytetracycline, flunixin meglumine, and pentoxifylline to inhibit equine MMP-2 and MMP-9 production.

ANIMALS

29 adult horses of various ages and breeds and either sex.

PROCEDURES

In part 1, horses received an IV administration of LPS (n = 5) or saline (0.9% NaCl) solution (5). Venous blood samples were collected before and at specified times for 24 hours after infusion. Plasma was harvested and analyzed for MMP-2 and MMP-9 activities via zymography. In part 2, horses received doxycycline (n = 5), oxytetracycline (5), flunixin meglumine (5), or pentoxifylline (4) before and for up to 12 hours after administration of LPS. Plasma was obtained and analyzed, and results were compared with results from the LPS-infused horses of part 1.

RESULTS

Administration of LPS significantly increased MMP-2 and MMP-9 activities in the venous circulation of horses. All MMP inhibitors significantly decreased LPS-induced increases in MMP activities but to differing degrees. Pentoxifylline and oxytetracycline appeared to be the most effective MMP-2 and MMP-9 inhibitors, whereas doxycycline and flunixin meglumine were more effective at inhibiting MMP-2 activity than MMP-9 activity.

CONCLUSIONS AND CLINICAL RELEVANCE

IV administration of LPS to horses caused increased venous plasma activities of MMP-2 and MMP-9. These MMP activities were reduced by pentoxifylline and oxytetracycline, suggesting that further evaluation of these medications for treatment and prevention of MMP-associated diseases in horses is indicated.

Curbing the focal adhesion kinase and its associated signaling events by pentoxifylline in MDA-MB-231 human breast cancer cells

Pentoxifylline (PTX) is a methylxanthine derivative currently being used in the treatment of peripheral vascular diseases. Recently, we had evaluated its action in human MDA-MB-231 breast cancer cells. PTX exhibited anti-metastatic activity by affecting key processes such as proliferation, adhesion, migration, invasion and apoptosis. In light of the preliminary findings, the present work accounts for the possible mechanistic insights of the pathways affected by PTX. Aberrant Focal Adhesion Kinase (FAK) signaling forms a key determinant in breast cancer and in view of this fact we had investigated downstream processes regulated by FAK. PTX at sub-toxic doses lowers the level of activated FAK, Extracellular Regulated Kinase or Mitogen Activated Protein Kinase (ERK/MAPK), Protein Kinase B (PKB/Akt) affecting cellular proliferation and survival. It blocks G1/S phase of cell cycle by inhibiting the expression of Cyclin D1/Cdk6. Further, it modulates the activities of RhoGTPases and alters actin organization resulting in decreased motility. PTX also delays tumor growth and inhibited blood vessel formation in vivo. In purview of these findings, PTX surely qualifies as a suitable prospect in the intervention of breast cancer.

Hepatoprotective effects of reynosin against thioacetamide-induced apoptosis in primary hepatocytes and mouse liver

The aim of this study was to identify the hepatoprotective effects of reynosin, sesquiterpenes from the leaves of Laurus nobilis, against thioacetamide (TAA)-induced apoptosis in primary hepatocyte cultures and an in vivo mouse model. Rat hepatocytes were isolated and pretreated with 0.13, 0.64, or 3.22 μM reynosin and then exposed to 100 mM TAA. Reynosin treatment significantly inhibited TAA-induced apoptosis and hepatocellular DNA damage in primary rat hepatocytes. We observed an increase in levels of antiapoptotic Bcl-2, Bcl-XL mRNA and a decrease in levels of proapoptotic Bax mRNA following reynosin treatment of hepatocytes. Apoptosis in BALB/c mice was induced with intra-peritoneal injection of 200 mg/kg TAA for 2 weeks every other day. Then reynosin (5 mg/kg) and TAA were intragastrically given for 3 weeks every other day. Aspartate aminotransferase and alanine aminotransferase levels in the blood of mice were decreased in the reynosin administration group. Bcl-2 and Bcl-XL mRNA levels were increased, and the Bax mRNA level was decreased in reynosin-treated mice. Thus, reynosin inhibited TAA-induced apoptosis in primary hepatocytes and an in vivo mouse model.

Phosphodiesterase 4 regulates the migration of B16-F10 melanoma cells

Phosphodiesterases (PDEs) are important regulators of signal transduction processes. Eleven PDE gene families (PDE1-11) have been identified and several PDE isoforms are selectively expressed in various cell types. PDE4 family members specifically hydrolyze cyclic AMP (cAMP). Four genes (PDE4A-D) are known to encode PDE4 enzymes, with additional diversity generated by the use of alternative mRNA splicing and the use of different promoters. While PDE4 selective inhibitors show therapeutic potential for treating major diseases such as asthma and chronic obstructive pulmonary disease, little is known concerning the role of PDE4 in malignant melanoma. In this study, we examined the role of PDE4 in mouse B16-F10 melanoma cells. In these cells, PDE4 activity was found to be ∼60% of total PDE activity. RT-PCR detected only PDE4B and PDE4D mRNA. Cell growth was inhibited by the cAMP analog, 8-bromo-cAMP, but not by the specific PDE4 inhibitors, rolipram and denbufylline, which increased intracellular cAMP concentrations. Finally, migration of the B16-F10 cells was inhibited by the PDE4 inhibitors and 8-bromo-cAMP, while migration was increased by a protein kinase A (PKA) inhibitor, PKI(14-22), and was not affected by 8-pCPT-2'-O-Me-cAMP, which is an analog of exchange protein activated by cAMP (Epac). The inhibitory effect of rolipram on migration was reversed by PKI(14-22). Based on these results, PDE4 appears to play an important role in the migration of B16-F10 cells, and therefore may be a novel target for the treatment of malignant melanoma.

Preclinical evaluation of the antimetastatic efficacy of Pentoxifylline on A375 human melanoma cell line

Melanoma is the most common malignant skin cancer, appears indestructible and is notoriously resistant to all current modalities of cancer treatment strategies. Pentoxifylline (PTX), a non-specific phosphodiesterase inhibitor, has shown to have radiosensitizing properties for a variety of cancers. Recently, we have shown that PTX exhibits antimetastatic and anti-angiogenic activities in B16F10 melanoma cells in vitro as well as in vivo. In the present study, we have demonstrated the anticancer and antimetastatic potential of PTX against A375 human melanoma cell line at sub-toxic doses. The results implicate that PTX at sub-toxic doses exhibited an inhibitory effect on the ability of cellular proliferation as shown by MTT and colony formation assay. It impedes migration and also induces apoptosis. A375 cells pretreated with PTX showed decrease in adhesion to both Matrigel and Collagen type IV. Further, Gelatin zymography result reveals that PTX treatment decreases the secretion of MMP2 and MMP9. Finally, PTX significantly inhibited A375 subcutaneous tumour xenograft growth without having any toxicity. Thus PTX at sub-toxic doses affected melanoma metastasis at multiple steps in vitro as well as tumour growth in vivo. These data demonstrate its antimetastatic potential and provide preclinical evidence for the development of PTX as a potential agent against metastatic melanoma.

Potentiation of anticancer drugs: effects of pentoxifylline on neoplastic cells

The drug efflux activity of P-glycoprotein (P-gp, a product of the mdr1 gene, ABCB1 member of ABC transporter family) represents a mechanism by which tumor cells escape death induced by chemotherapeutics. In this study, we investigated the mechanisms involved in the effects of pentoxifylline (PTX) on P-gp-mediated multidrug resistance (MDR) in mouse leukemia L1210/VCR cells. Parental sensitive mouse leukemia cells L1210, and multidrug-resistant cells, L1210/VCR, which are characterized by the overexpression of P-gp, were used as experimental models. The cells were exposed to 100 μmol/L PTX in the presence or absence of 1.2 μmol/L vincristine (VCR). Western blot analysis indicated a downregulation of P-gp protein expression when multidrug-resistant L1210/VCR cells were exposed to PTX. The effects of PTX on the sensitization of L1210/VCR cells to VCR correlate with the stimulation of apoptosis detected by Annexin V/propidium iodide apoptosis necrosis kit and proteolytic activation of both caspase-3 and caspase-9 monitored by Western blot analysis. Higher release of matrix metalloproteinases (MMPs), especially MMP-2, which could be attenuated by PTX, was found in L1210/VCR than in L1210 cells by gelatin zymography in electrophoretic gel. Exposure of resistant cells to PTX increased the content of phosphorylated Akt kinase. In contrast, the presence of VCR eliminated the effects of PTX on Akt kinase phosphorylation. Taken together, we conclude that PTX induces the sensitization of multidrug-resistant cells to VCR via downregulation of P-gp, stimulation of apoptosis and reduction of MMPs released from drug-resistant L1210/VCR cells. These facts bring new insights into the mechanisms of PTX action on cancer cells.

EILDV-conjugated, etoposide-loaded biodegradable polymeric micelles directing to tumor metastatic cells overexpressing α4β1 integrin

In the present study, poly(ethylene glycol)-b-poly(ε-caprolactone) micelles loaded with etoposide (ETO) were formulated and further conjugated with pentapeptide Glu-Ile-Leu-Asp-Val (EILDV) to target α4β1 integrin receptor overexpressed on metastatic tumor cell. Using a distinct ratio of carboxyl-terminated poly(ethylene glycol)-block-poly(ε-caprolactone) (HOOC-PEG-b-PCL) to methoxy-poly(ethylene glycol)-block-poly(ε-caprolactone (CH₃O-PEG-b-PCL) polymers, we formulated a series of micellar formulations having different surface densities of EILDV and observed optimum cellular uptake of micelles with 10% EILDV surface density by B16F10 cells. The cytotoxicity of EILDV-conjugated micelles was observed close to 1.5-fold higher than plain ETO after 72 h of drug incubation, demonstrating controlled release of drug inside the cell after enhanced intracellular uptake with the ability to selectively target cancer cells. In addition, EILDV-conjugated micelles inhibited the migration of B16F10 cells effectively compared with plain ETO and non-conjugated micellar formulations when cells were treated with equivalent cytotoxic concentration of the drug, i.e., IC₂₅. B16F10 cells treated with EILDV-conjugated micelles showed a significant reduction in the attachment of cells to the substrate-coated plate compared with non-conjugated micellar formulations, implying retention of the biological activity of EILDV after coupling to micelles. Furthermore, the in vivo experimental metastasis assay conducted on C57BL/6 mice demonstrated significant activity of EIDLV-conjugated micelles in the reduction of pulmonary metastatic nodule formation in both pretreatment and post-treatment methods. In conclusion, EIDLV-conjugated micelles showed higher efficacy in the treatment of metastasis and would be a promising approach in the treatment of metastasis.

Synthesis, antitumor, and DNA binding behavior of novel 4-(2-hydroxyquinolin-3-yl)-6-phenyl-5, 6 dihydropyrimidin derivatives in aqueous medium

This article deals with the synthesis of 4-(2-hydroxyquinolin-3-yl)-6-phenyl-5,6-dihydropyrimidin derivatives (2a-f), on condensation with various aromatic aldehydes and ketones in aqueous ethanolic NaOH solution yielding the corresponding chalcones (3). These chalcones were further reacted with thiourea/urea in the presence of a base, which led to the formation of the titled derivatives (2a-f). The newly synthesized heterocyles were characterized by elemental analysis, FTIR, (1)HNMR, and electronic and mass spectral data. The compounds (2a and 2b) were evaluated for in vitro cyctotoxicity against human breast adenocarcinoma cell (MCF-7). In MTT cytotoxicity studies, both quinolinde derivatives were found most effective. The binding interaction behavior of the compound (2a) and (2d) with calf thymus-DNA (CT-DNA) was studied by electronic spectra, viscosity measurements, and thermal denaturation studies. On binding to CT-DNA, the absorption spectrum underwent bathochromic and hypochromic shifts. The binding constant (K(b)) observed 4.3 x 10(5) M(-1) for (2a), and 3.8 x 10(5) M(-1) for (2d) suggested that compound (2a) binds more strongly with base pairs than (2d).

Antimetastatic Action of Pentoxifylline, a Methyl Xanthine Derivative, Through its Effect on PKC Mediated Integrin Transport in B16F10 Melanoma Cells

Background

Integrins are adhesion molecules known to regulate cellular processes like adhesion, migration and proliferation. At the same time role of integrin in progress of cancer metastasis is well established, increased integrin expression is reported to be linked to high metastasis potential of cells. Pentoxifylline a methyl xanthine derivative is a potent antimetastatic agent. Studies on the mechanism of inhibition of lung homing of B16F10 melanoma cells by PTX shows that it can inhibit cell- Extracellular Matrix adhesion, cell surface integrin expression as well as Protein kinase C activity. Previous study from our laboratory have shown PTX treatment can selectively inhibit the cell surface expression of α5 integrin in B16F10 cells without affecting its total cellular protein levels. Numerous studies have documented that differences in surface expression and distribution of integrins affects metastasis. The purpose of present study is to observe the effect of PTX on cellular distribution/ redistribution of integrins and to study the underlying molecular mechanism of PTX action.

Methods

Integrin internalization and transport was observed using immunofluorescence confocal microscopy. PKC activity was determined using MBP4-14 as a substrate. Immunoprecipitation and western blotting was used to show association between PKC and α5 integrin, cell adhesion assay was performed using fibronectin/fibrinogen as substrate.

Results

Immunofluorescence studies showed that PTX treatment caused a redistribution of α5 integrins from the plasma membrane to a perinuclear compartment where it colocalized with Transferrin receptor and Rab-11 GTPase. Rate of integrin internalization and recycling showed that PTX inhibited the recycling of α5 integrins from perinuclear recycling endosomes. PTX is reported to affect kinases; here we showed that PTX inhibited total PKC activity. Association between α5β1 integrin and PKC is studied using Immunoprecipitation which show that PTX affects α5β1 integrin associated PKC activity without affecting the levels of PKC. Studying the effect of delay in integrin recycling on cell functionality showed that it affects spreading of cells on fibronectin/fibrinogen.

Conclusions

Data in the present study shows that PTX interferes with PKC activity bringing about a change in integrin distribution, and there by affecting the functionality of the cell. And this may possibly serve as one of the mechanisms for antimetastatic action of PTX.

The pharmacologic basis for the treatment of developmental and acute laminitis

The treatment of laminitis has been fraught with confusion and controversy for several decades, mainly because of a lack of understanding of the pathophysiology of the disease process. However, recent advances in laminitis research have greatly improved our understanding of the disease process. This article discusses the various treatment options for laminitis in the context of the findings of recent scientific investigations of laminitis pathophysiology.

In vitro and in vivo anticancer properties of a Calcarea carbonica derivative complex (M8) treatment in a murine melanoma model

Background

Melanoma is the most aggressive form of skin cancer and the most rapidly expanding cancer in terms of worldwide incidence. Chemotherapeutic approaches to treat melanoma have had only marginal success. Previous studies in mice demonstrated that a high diluted complex derived from Calcarea carbonica (M8) stimulated the tumoricidal response of activated lymphocytes against B16F10 melanoma cells in vitro.

Methods

Here we describe the in vitro inhibition of invasion and the in vivo anti-metastatic potential after M8 treatment by inhalation in the B16F10 lung metastasis model.

Results

We found that M8 has at least two functions, acting as both an inhibitor of cancer cell adhesion and invasion and as a perlecan expression antagonist, which are strongly correlated with several metastatic, angiogenic and invasive factors in melanoma tumors.

Conclusion

The findings suggest that this medication is a promising non-toxic therapy candidate by improving the immune response against tumor cells or even induce direct dormancy in malignancies.

Pentoxifylline impedes migration in B16F10 melanoma by modulating Rho GTPase activity and actin organisation

Cancer cell migration is a hallmark of metastatic cascade and compounds that can intervene in this process are clinically important. Pentoxifylline (PTX), a methyl xanthine derivative, inhibits B16F10 melanoma lung homing by inhibiting F10 invasion, MMP secretion and adhesion to matrix components. However, its effect on B16F10 migration remained unexamined, which we investigated in the present study. PTX significantly inhibits F10 migration in scratch wound assay. Elevation in cAMP levels inhibits F10 migration and PTX mediated inhibition of the process was found to be, in part, due to an increase in cellular cAMP levels. PTX induces Protein Kinase A (PKA) activity and PKA inhibitor partly reversed its effects on F10 motility. RhoA and Rac1 GTPases induce B16F10 motility and PTX was found to inhibit migration by affecting these molecules. Stress fibres and lamellipodial protrusions reduced significantly. This was accompanied with inhibition in RhoA and Rac1 membrane localisation. A stark inhibition in RhoA-GTP bound form was also observed. Taken together, the results indicate that PTX, through its phosphodiesterase action, inhibits RhoGTPases and associated actin organisation in B16F10 melanoma, thereby inhibiting cell motility.

Suramin augments the antitumor and antimetastatic activity of pentoxifylline inB16F10 melanoma

Rapid tumor growth and metastasis are 2 major problems associated with treatment of malignant melanoma. Therefore, drugs that can intervene these processes are of clinical importance. Pentoxifylline (PTX), a methyl xanthine derivative, has been shown to inhibit B16F10 melanoma tumor growth and metastasis. We hypothesized that suramin when combined with PTX enhances its antineoplastic effects, which we have examined using the B16F10 mouse melanoma model. Suramin in simultaneous or sequential combination potentiated the cytotoxic effects of PTX on B16F10 cells. PTX arrested cells in the G0-G1 phase and suramin augmented the effects. Both the drugs inhibited F10 adhesion to laminin, matrigel and collagen type IV and showed enhanced inhibition in combination The combination also demonstrated significantly higher inhibition in cell motility (p = 0.002) and invasion through matrigel (p = 0.005) as compared to the single agents. Suramin synergized with PTX in its effects on secretion of MMP-9 gelatinase. DBA2/J mice implanted with intradermal B16F10 tumor were used as a model to study tumor growth. Animals were intratumorally treated with 50 mg/kg of PTX, 10 mg/kg of suramin and their combinations. Simultaneous administration of the drugs inhibited tumor growth by 5- to 6-folds. Tumor growth was completely blocked in sequential regimen with regression in some cases. The number and size of metastatic nodules on lung was also reduced significantly by the combination treatment. In conclusion, the novel combination of PTX and suramin has synergistic antitumor and antimetastatic activity in B16F10 melanoma and may be a promising approach in treatment of patients suffering from malignant melanoma.