Novel 4,4'-diether-2,2'-bipyridine cisplatin analogues are more effective than cisplatin at inducing apoptosis in cancer cell lines.

The synthesis and characterization of dichloro(4,4'-bis[methoxy]-2,2'-bipyridine)platinum (1) and dichloro(4,4'-bis[3-methoxy-n-propyl]-2,2'-bipyridine)platinum (2) are described. As analogues to CDDP, these 4,4'-disubstituted 2,2'-bipyridine complexes exhibit decreased EC(50) values of 10-100 times in cancer cell lines of the lung, prostate, and melanoma with several combinations of complex and cell line less than 10 microM. Flow cytometry data indicate 'blocks' of MDA-MD-435 cycle by 1 (G2/M) and 2 (S). Observed cell survival trends in the presence of 1, 2 under ionizing radiation mimic those of CDDP. Preliminary structure activity relationships are discussed for the 4,4'-substitutions made on the bipyridine ring.

Perillyl alcohol and methyl jasmonate sensitize cancer cells to cisplatin.

Breast cancer is the second leading cause of cancer deaths among women in the United States. Several treatment options exist, with different side effects. To alleviate the side effects, several research groups have studied chemotherapeutic effects of plant compounds on cancer cells. These could be used as an alternative treatment option either alone or in combination with other chemotherapeutic drugs. The aim of this study was to evaluate the activity of a combination of perillyl alcohol (POH), methyl jasmonate (MJ) with cisplatin to define the most effective schedule and to investigate the mechanism of action in breast cancer cells. POH and MJ treatment (20% decrease in cell viability concentration) enhanced the cytotoxicity for subsequent exposure to cisplatin in MDA-MB-435 and MDA-MB-231 cells. Combination treatment of POH and MJ blocked cells at the G0/G1 phase of the cell cycle and the addition of cisplatin forced the cells to progress through the cell cycle and induced apoptosis. Apoptotic mechanistic studies indicated that POH and MJ treatment activated tumor necrosis factor receptor 1 and this was further increased by the addition of cisplatin. It was also found that mitochondrial membrane potential decreased with POH and MJ treatment; this effect was further enhanced by cisplatin treatment. These findings contributed to a better understanding of molecular mechanism of apoptosis in combination treatment of POH, MJ, and cisplatin. Results also showed that the combination treatment of three drugs is more effective than single drug alone or two drugs together.

Delayed cytotoxic effects of methyl jasmonate and cis-jasmone induced apoptosis in prostate cancer cells.

Advanced prostate cancer cells are typically hormone independent, resistant to apoptosis and do not respond to chemotherapeutic agents. The ability of methyl jasmonate (MJ) and cis-jasmone (CJ) to inhibit growth in hormone independent prostate cancer cell lines, PC-3 and DU-145, was evaluated. CJ and MJ inhibited cell growth, induced cell cycle arrest and apoptosis. Detailed studies with the PC-3 cell line revealed that 2 mM CJ or MJ treatment resulted in caspase 3 activation and Tumor Necrosis Factor Receptor 1 (TNFR1) activation, all hallmarks of apoptosis. These phytochemicals could be useful in the management of advanced prostate cancer.

Methyl jasmonate decreases membrane fluidity and induces apoptosis through tumor necrosis factor receptor 1 in breast cancer cells.

In recent years, studies with plant compounds have shown both chemotherapeutic and chemopreventive properties. This study with plant stress hormones (jasmonates) showed growth inhibitory effects in breast cancer cells. cis-Jasmone and methyl jasmonate (MJ) inhibited the long-term proliferation of MDA-MB-435 and MCF-7 cells. Cell cycle analysis showed G0/G1 and S-phase arrest with increasing apoptotic population. Cellular signaling studies with MJ showed decreased membrane fluidity and activation of extrinsic and intrinsic apoptotic pathways. Specifically in extrinsic apoptotic pathway increased expression of TNF receptor 1, activation of mitogen-activated protein kinase and caspase-8 was observed. MJ also decreased the mitochondrial membrane potential and activated caspase-3 in breast cancer cells. In conclusion our results revealed novel-signaling mechanism of MJ in breast cancer cells, indicating that MJ could have potential applications for chemotherapeutic purposes.

Phenylboronic acid selectively inhibits human prostate and breast cancer cell migration and decreases viability.

We compared the in vitro effect of boric acid (BA) versus phenylboronic acid (PBA) on the migration of prostate and breast cancer cell lines and non-tumorigenic cells from the same tissues. Treatment at 24 hours with BA (< or =500 microM) did not inhibit chemotaxis on fibronectin in any cell line. However, treatment over the same time course with concentrations of PBA as low as 1 muM significantly inhibited cancer cell migration without effecting non-tumorigenic cell lines. The compounds did not affect cell adhesion or viability at 24 hours but did alter morphology; both decreased cancer cell viability at eight days. These results suggest that PBA is more potent than BA in targeting the metastatic and proliferative properties of cancer cells.

Perillyl alcohol and perillic acid induced cell cycle arrest and apoptosis in non small cell lung cancer cells.

Plant products such as perillyl alcohol have been reported to possess anti-tumor activities against a number of human cancers though the mechanism of action has not yet been elucidated. The effects of perillyl alcohol (POH) and its metabolite perillic acid (PA) on the proliferation of non small cell lung cancer (NSCLC, A549, and H520) cells were investigated. Both POH and PA elicited dose-dependent cytotoxicity, induced cell cycle arrest and apoptosis with increasing expression of bax, p21 and caspase-3 activity in both the cell lines. Combination studies revealed that exposing the cells to an IC50 concentration of POH or PA sensitized the cells to cisplatin and radiation in a dose-dependent manner. These results indicate that POH and PA in combination therapy may have chemotherapeutic value against NSCLC.

Heat shock protein 27 protects against aminolevulinic acid-mediated photodynamic therapy-induced apoptosis and necrosis in human breast cancer cells.

This study utilized two breast cancer cell lines differing only in their expression of heat shock protein 27 (hsp27). The DB46 cell line was engineered to express high constitutive levels of hsp27, while the DC4 cell line expresses normal low levels of hsp27. The cells were incubated in 1 mM aminolevlinic acid (ALA) 4 hr prior to light exposures (635 nm) ranging from 1 to 20 J/cm2. Both cell lines displayed a dose response to photodynamic therapy (PDT) as assayed by clonogenic survival. LD50s of 2.68 and 1.27 J/cm2 were observed for DB46 and DC4 cells respectively. ALA-PDT-induced resistance to both apoptosis and necrosis in the DB46 cell line was found from TUNEL assays and fluorescence microscopy studies using propidium iodide and Hoechst staining.

Jasmonates induce apoptosis and cell cycle arrest in non-small cell lung cancer lines.

The jasmonates, cis-jasmone (CJ) and methyl jasmonate (MJ), were investigated for their effects against NSCLC cell lines A549 and H520. CJ or MJ inhibited the proliferation of both cell lines in a dose-dependent manner as well as induced cell cycle arrest in the G2/M phase. Apoptosis was observed following treatment with CJ or MJ as indicated by Hoechst staining and confirmed by dual annexin V-fluorescein isothiocyanate (FITC)/prodium iodide (PI) and DAPI (4',6-diamidine-2'-phenylindole dihydrochloride) staining. p38 and extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation was observed with increased expression of bax, p21, and caspase-3 activity. These observations indicate that jasmonates may have a therapeutic value in the treatment of lung cancer.

A fluorine containing bipyridine cisplatin analog is more effective than cisplatin at inducing apoptosis in cancer cell lines.

Novel cisplatin analogs dichloro[4,4'-bis(4,4,4-trifluorobutyl)-2,2'-bipyridine]platinum (1) and fac-tricarbonylchloro[4,4'-bis(4,4,4-trifluorobutyl)-2,2'-bipyridine]rhenium (3) were synthesized and evaluated for their cytotoxicity. While 3 was not cytotoxic, 1 was 14 to 125 times more lethal than cisplatin in breast, prostate, and lung cancer cell lines. Compound 1 was able to induce apoptosis and the presence of the platinum atom was essential to its function as a cytotoxin.

Influence of light fluence rate on the effects of photodynamic therapy in an orthotopic rat glioma model.

OBJECT: Failure of treatment for high-grade gliomas is usually due to local recurrence at the site of resection, indicating that a more aggressive local therapy could be beneficial. Photodynamic therapy (PDT) is a local treatment involving the administration of a tumor-localizing photosensitizing drug, in this case aminolevulinic acid (ALA). The effect depends on the total light energy delivered to the target tissue, but may also be influenced by the rate of light delivery. METHODS: In vitro experiments showed that the sensitivity to ALA PDT of BT4C multicellular tumor spheroids depended on the rate of light delivery (fluence rate). The BT4C tumors were established intracranially in BD-IX rats. Microfluorometry of frozen tissue sections showed that photosensitization is produced with better than 200:1 tumor/normal tissue selectivity after ALA injection. Four hours after intraperitoneal ALA injection (125 mg/kg), 26 J of 632 nm light was delivered interstitially over 15 (high fluence rate) or 90 (low fluence rate) minutes. Histological examination of animals treated 14 days after tumor induction demonstrated extensive tumor necrosis after low-fluence-rate PDT, but hardly any necrosis after high-fluence-rate treatment. Neutrophil infiltration in tumor tissue was increased by PDT, but was similar for both treatment regimens. Low-fluence-rate PDT administered 9 days after tumor induction resulted in statistically significant prolongation of survival for treated rats compared with nontreated control animals. CONCLUSIONS: Treatment with ALA PDT induced pronounced necrosis in tumors only if the light was delivered at a low rate. The treatment prolonged the survival for tumor-bearing animals.

Photodynamic therapy of newly implanted glioma cells in the rat brain.

BACKGROUND AND OBJECTIVE: A syngeneic rat brain tumor model is used to investigate the effects of aminolevulinic acid (ALA)-mediated photodynamic therapy (PDT) on small clusters of tumor cells sequestered in normal brain. STUDY DESIGN/MATERIALS AND METHODS: Biodistribution studies on tumor-bearing animals were undertaken in order to determine the occurrence of photosensitizer in tumor cells invading normal brain. ALA-PDT toxicity in normal brain and gross tumor were evaluated from histopathology. Effects of PDT on isolated glioma cells in normal brain were investigated by treating animals 48 hours after tumor cell implantation. RESULTS: Fluorescence microscopy of frozen tissue sections showed that photosensitizer content was limited and variable in tumor tissue invading normal brain. ALA-PDT with high light doses resulted in significant damage to both gross tumor and normal brain, however, the treatment failed to prolong survival of animals with newly implanted glioma cells. In contrast, animals inoculated with tumor cells pre-incubated in vitro with ALA showed a significant survival advantage in response to PDT. CONCLUSION: The results show that ALA-PDT could not prevent tumors from forming if treatment was performed shortly after tumor initiation. This was likely due to inadequate levels of ALA/PpIX in the glioma cells.

The Promise of Integrins as Effective Targets for Anticancer Agents.

This review will briefly describe integrin function, address why integrins are attractive targets for chemotherapeutic drug design, and discuss some ongoing studies aimed at inhibiting integrin activity. Integrins are cell surface heterodimeric receptors. They modulate many cellular processes including: growth, death (apoptosis), adhesion, migration, and invasion by activating several signaling pathways. Many potential chemotherapeutic agents target integrins directly (eg, polypeptides, monoclonal antibodies, adenovirus vectors). These agents may be clinically useful in controlling the metastatic spread of cancer.