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Papers by Michele Franco
Molecules, 2020
A series of neutral mixed-ligand [HB(pz)3]Ag(PR3) silver(I) complexes (PR3 = tertiary phosphine, ... more A series of neutral mixed-ligand [HB(pz)3]Ag(PR3) silver(I) complexes (PR3 = tertiary phosphine, [HB(pz)3]− = tris(pyrazolyl)borate anion), and the corresponding homoleptic [Ag(PR3)4]BF4 compounds have been synthesized and fully characterized. Silver compounds were screened for their antiproliferative activities against a wide panel of human cancer cells derived from solid tumors and endowed with different platinum drug sensitivity. Mixed-ligand complexes were generally more effective than the corresponding homoleptic derivatives, but the most active compounds were [HB(pz)3]Ag(PPh3) (5) and [Ag(PPh3)4]BF4 (10), both comprising the lipophilic PPh3 phosphine ligand. Detailed mechanistic studies revealed that both homoleptic and heteroleptic silver complexes strongly and selectively inhibit the selenoenzyme thioredoxin reductase both as isolated enzyme and in human ovarian cancer cells (half inhibition concentration values in the nanomolar range) causing the disruption of cellular thio...
Anti-Cancer Agents in Medicinal Chemistry, 2009
Metal-based antitumor drugs play a relevant role in antiblastic chemotherapy. Cisplatin is regard... more Metal-based antitumor drugs play a relevant role in antiblastic chemotherapy. Cisplatin is regarded as one of the most effective drugs, even if severe toxicities and drug resistance phenomena limit its clinical use. Therefore, in recent years there has been a rapid expansion in research and development of novel metal-based anticancer drugs to improve clinical effectiveness, to reduce general toxicity and to broaden the spectrum of activity. The variety of metal ion functions in biology has stimulated the development of new metallodrugs other than Pt drugs with the aim to obtain compounds acting via alternative mechanisms of action. Among non-Pt compounds, copper complexes are potentially attractive as anticancer agents. Actually, since many years a lot of researches have actively investigated copper compounds based on the assumption proposal that endogenous metals may be less toxic. It has been established that the properties of copper-coordinated compounds are largely determined by...
Lasers in Medical Science, 2012
Lasers in Medical Science, 2013
Journal of Cell Science, 2004
Nature Cell Biology, 2005
Proceedings of The National Academy of Sciences, 1998
Optics Communications, 1994
European Physical Journal D, 1999
A two-dimensional axisymmetric model of the propagation of intense femtosecond laser pulses throu... more A two-dimensional axisymmetric model of the propagation of intense femtosecond laser pulses through dispersion-free transparent media is described. The effects of diffraction, nonlinear Kerr effect (instantaneous and retarded) and multiphoton ionisation are included. Numerical results concerning air and other gases are discussed. In particular, time self-compression of femtosecond pulses is predicted. Stable self-guided pulses are simulated, in agreement with recent experimental observations.
Journal of The Optical Society of America B-optical Physics, 2002
Optics Communications, 2005
Optics Communications, 2001
We report on a new type of permanent damage obtained in bulk fused silica by focusing IR femtosec... more We report on a new type of permanent damage obtained in bulk fused silica by focusing IR femtosecond laser pulses with microjoule energy. It consists of an uniaxial birefringence zone over a lateral size of a few microns and a depth of a few tens of microns. The birefringence zone is followed by sub-micrometer filamentary cracks extending up to 80 μm. Nonlinear pulse propagation plays a crucial role in the onset of this type of damage.
Physical Review Letters, 2004
We show that it is possible to organize regular filamentation patterns in air by imposing either ... more We show that it is possible to organize regular filamentation patterns in air by imposing either strong field gradients or phase distortions in the input-beam profile of an intense femtosecond laser pulse. A comparison between experiments and 3+1 dimensional numerical simulations confirms this concept and shows for the first time that a control of the transport of high intensities over long distances may be achieved by forcing this well ordered propagation regime. In this case, deterministic effects prevail in multiple femtosecond filamentation, and no transition to the optical turbulence regime is obtained [Phys. Rev. Lett. 83, 2938 (1999)]].
Molecules, 2020
A series of neutral mixed-ligand [HB(pz)3]Ag(PR3) silver(I) complexes (PR3 = tertiary phosphine, ... more A series of neutral mixed-ligand [HB(pz)3]Ag(PR3) silver(I) complexes (PR3 = tertiary phosphine, [HB(pz)3]− = tris(pyrazolyl)borate anion), and the corresponding homoleptic [Ag(PR3)4]BF4 compounds have been synthesized and fully characterized. Silver compounds were screened for their antiproliferative activities against a wide panel of human cancer cells derived from solid tumors and endowed with different platinum drug sensitivity. Mixed-ligand complexes were generally more effective than the corresponding homoleptic derivatives, but the most active compounds were [HB(pz)3]Ag(PPh3) (5) and [Ag(PPh3)4]BF4 (10), both comprising the lipophilic PPh3 phosphine ligand. Detailed mechanistic studies revealed that both homoleptic and heteroleptic silver complexes strongly and selectively inhibit the selenoenzyme thioredoxin reductase both as isolated enzyme and in human ovarian cancer cells (half inhibition concentration values in the nanomolar range) causing the disruption of cellular thio...
Anti-Cancer Agents in Medicinal Chemistry, 2009
Metal-based antitumor drugs play a relevant role in antiblastic chemotherapy. Cisplatin is regard... more Metal-based antitumor drugs play a relevant role in antiblastic chemotherapy. Cisplatin is regarded as one of the most effective drugs, even if severe toxicities and drug resistance phenomena limit its clinical use. Therefore, in recent years there has been a rapid expansion in research and development of novel metal-based anticancer drugs to improve clinical effectiveness, to reduce general toxicity and to broaden the spectrum of activity. The variety of metal ion functions in biology has stimulated the development of new metallodrugs other than Pt drugs with the aim to obtain compounds acting via alternative mechanisms of action. Among non-Pt compounds, copper complexes are potentially attractive as anticancer agents. Actually, since many years a lot of researches have actively investigated copper compounds based on the assumption proposal that endogenous metals may be less toxic. It has been established that the properties of copper-coordinated compounds are largely determined by...
Lasers in Medical Science, 2012
Lasers in Medical Science, 2013
Journal of Cell Science, 2004
Nature Cell Biology, 2005
Proceedings of The National Academy of Sciences, 1998
Optics Communications, 1994
European Physical Journal D, 1999
A two-dimensional axisymmetric model of the propagation of intense femtosecond laser pulses throu... more A two-dimensional axisymmetric model of the propagation of intense femtosecond laser pulses through dispersion-free transparent media is described. The effects of diffraction, nonlinear Kerr effect (instantaneous and retarded) and multiphoton ionisation are included. Numerical results concerning air and other gases are discussed. In particular, time self-compression of femtosecond pulses is predicted. Stable self-guided pulses are simulated, in agreement with recent experimental observations.
Journal of The Optical Society of America B-optical Physics, 2002
Optics Communications, 2005
Optics Communications, 2001
We report on a new type of permanent damage obtained in bulk fused silica by focusing IR femtosec... more We report on a new type of permanent damage obtained in bulk fused silica by focusing IR femtosecond laser pulses with microjoule energy. It consists of an uniaxial birefringence zone over a lateral size of a few microns and a depth of a few tens of microns. The birefringence zone is followed by sub-micrometer filamentary cracks extending up to 80 μm. Nonlinear pulse propagation plays a crucial role in the onset of this type of damage.
Physical Review Letters, 2004
We show that it is possible to organize regular filamentation patterns in air by imposing either ... more We show that it is possible to organize regular filamentation patterns in air by imposing either strong field gradients or phase distortions in the input-beam profile of an intense femtosecond laser pulse. A comparison between experiments and 3+1 dimensional numerical simulations confirms this concept and shows for the first time that a control of the transport of high intensities over long distances may be achieved by forcing this well ordered propagation regime. In this case, deterministic effects prevail in multiple femtosecond filamentation, and no transition to the optical turbulence regime is obtained [Phys. Rev. Lett. 83, 2938 (1999)]].