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Introduction: In chronic myeloid leukemia (CML), about half of the patients achieving a deep and stable molecular response with tyrosine kinase inhibitors (TKIs) may discontinue TKI treatment without disease recurrence. As such, treatment-free remission (TFR) has become an ambitious goal of treatment. Given the evidence that deepness and duration of molecular response are necessary but not sufficient requisites for a successful TFR, additional biological criteria are needed to identify CML patients suitable for efficacious discontinuation. Leukemia stem cells (LSCs) are supposed to be the reservoir of the disease. Previously, we demonstrated that residual circulating CD34+/CD38-/CD26+ LSCs were still detectable in a consistent number of CML patients during TFR.Methods: CML LSCs could be easily identified by flow-cytometry as they express the CD34+/CD38-/CD26+ phenotype. In this study, we explored the role of these cells and their correlation with molecular response in a cohort of 109 consecutive chronic phase CML patients prospectively monitored from the time of TKI discontinuation.Results: After a median observation time of 33 months from TKI discontinuation, 38/109 (35%) patients failed TFR after a median time of 4 months, while 71/109 (65%) patients are still in TFR. At TKI discontinuation, peripheral blood CD26+LSCs were undetectable in 48/109 (44%) patients and detectable in 61/109 (56%). No statistically significant correlation between detectable/undetectable CD26+LSCs and the rate of TFR loss was found (p = 0.616). The incidence of TFR loss based on the type of TKI treatment was statistically significant for imatinib treatment compared to that of nilotinib (p = 0.039). Exploring the behavior of CD26+LSCs during TFR, we observed fluctuating values that were very variable between patients, and they were not predictive of TFR loss.Discussion: Up to date, our results confirm that CD26+LSCs are detectable at the time of TKI discontinuation and during TFR. Moreover, at least for the observation median time of the study, the persistence of “fluctuating” values of residual CD26+LSCs does not hamper the possibility to maintain a stable TFR. On the contrary, even patients discontinuing TKI with undetectable CD26+LSCs could undergo TFR loss. Our results suggest that factors other than residual LSCs “burden” playing an active role in controlling disease recurrence. Additional studies evaluating CD26+LSCs’ ability to modulate the immune system and their interaction in CML patients with very long stable TFR are ongoing.

In Chronic Myeloid Leukemia (CML) patients, CD34+/CD38-/CD26+ cell population represents a “CML specific” Leukemia Stem Cell (LSC) compartment. Indeed, preliminary studies showed that the expression of CD26 discriminates bone marrow CML Leukemic Stem Cells (LSCs) from nor-mal Hematopoietic Stem Cells (HSCs) or from LSCs of other myeloid neoplasms. We were first to demonstrate that at diagnosis CD34+/CD38-/CD26+ cells are easily measurable also in Peripheral Blood (PB) and that residual circulating CD26+LSCs persist, with a fluctuating trend, in most pa-tients in optimal response during treatment with Tyrosine Kinase Inhibitors (TKIs) and even after successful TKI discontinuation. These data corroborate and confirm the possibility of using flow-cytometry CD26+ evaluation as an important diagnostic tool that, combined with molecular biology and cytogenetic, could provide a rapid diagnosis of Chronic Phase (CP) CML starting from a simple PB sample. Yet, few data are available regarding the behavior of CD26+LSCs during Accelerated Phase (AP) or Blast Phase (BP) CML and the role, if any, this peculiar staminal cell compartment may play in disease progression. In the present study we compared the presence and phenotypic characteristics of circulating CD26+LSCs in CP CML patients at diagnosis, during AP and in cases of progression to lymphoid BP, inquiring a possible role of these cells during dis-ease evolution.

Bis(pyrazol-1-yl)acetic acid (HC(pz)2COOH) and bis(3,5-dimethyl-pyrazol-1-yl)acetic acid (HC(pzMe2)2COOH) were converted into the methyl ester derivatives 1 (LOMe) and 2 (L2OMe), respectively, and were used for the preparation of Cu(I) and Cu(II) complexes 3–10. The copper(II) complexes were prepared by the reaction of CuCl2·2H2O or CuBr2 with ligands 1 and 2 in methanol solution. The copper(I) complexes were prepared by the reaction of Cu[(CH3CN)4]PF6 and 1,3,5-triaza-7-phosphaadamantane (PTA) or triphenylphosphine with LOMe and L2OMe in acetonitrile solution. Synchrotron radiation-based complementary techniques (XPS, NEXAFS, and XAS) were used to investigate the electronic and molecular structures of the complexes and the local structure around copper ions in selected Cu(I) and Cu(II) coordination compounds. All Cu(I) and Cu(II) complexes showed a significant in vitro antitumor activity, proving to be more effective than the reference drug cisplatin in a panel of human cancer cell lines, and were able to overcome cisplatin resistance. Noticeably, Cu complexes appeared much more effective than cisplatin in 3D spheroid cultures. Mechanistic studies revealed that the antitumor potential did not correlate with cellular accumulation but was consistent with intracellular targeting of PDI, ER stress, and paraptotic cell death induction.

Six enantiomerically pure, oxaliplatin-like, platinum compounds (two platinum(II) and four platinum(IV)), all containing unsaturated cyclic diamine trans-1,2-diamino-4-cyclohexene (DACHEX) as a substitute for the trans-1,2-diaminocyclohexane used in oxaliplatin, were investigated. The complexes were characterized by elemental analyses, ESI-MS, and 1H-NMR spectroscopy. For the four Pt(IV) complexes the electrochemical redox behaviour, investigated by cyclic voltammetry, showed that all complexes possess reduction potentials suitable for activation in vivo. The antiproliferative activity was assessed in vitro on human cancer cell lines, also selected for resistance to platinum-based drugs or belonging to the MultiDrug-Resistant (MDR) phenotype. All complexes exhibited antiproliferative activity superior to that of cisplatin and almost equivalent to or better than that of oxaliplatin; moreover, most complexes were also capable of overcoming both the cisplatin- and the oxaliplatin-resistance. By comparing the effectiveness of the enantiomerically pure compounds with the racemic one, the R,R enantiomer emerged as the most effective in the case of Pt(II) complexes whereas the S,S enantiomer was the most effective in the case of the Pt(IV) derivatives. From the results obtained also against 3D spheroid tumor models, cis,trans,cis-[Pt(OXA)(OBz)2(1S,2S-DACHEX)] (OBz = benzoate) emerged as the most promising candidate for further preclinical investigation.

The Pt(IV) complexes based on (SP-4-2)-dichlorido(cyclohexane-1,4-diamine)platinum(II) (kiteplatin) and the histone deacetylase inhibitor 2-(2-propynyl)octanoic acid (POA) were investigated. Since POA contains a chiral carbon, all the possible Pt(IV) isomers were prepared and characterized, and their antiproliferative activity on six cancer cell lines was compared with that of the corresponding Pt(IV) complexes containing the cyclohexane-1R,2R-diamine equatorial ligand. To justify the very good antiproliferative activity (nanomolar IC50), the polarity, lipophilicity, permeability, and cell accumulation of the complexes were studied. Overall, the two series of Pt(IV) complexes showed similar cell penetration properties, being significantly better than that of the Pt(II) reference compounds. Finally, a representative compound of the whole set of complexes (i.e., that based on cyclohexane-1R,2R-diamine and racemic POA) was tested in vivo on mice bearing Lewis lung carcinoma, showing good tumor growth inhibition with negligible body weight loss.

Bis(pyrazol-1-yl)- and bis(3,5-dimethylpyrazol-1-yl)-acetates were conjugated with the 2-hydroxyethylester and 2-aminoethylamide derivatives of the antineoplastic drug lonidamine to prepare Cu(I) and Cu(II) complexes that might act through synergistic mechanisms of action due to the presence of lonidamine and copper in the same chemical entity. Synchrotron radiation-based complementary techniques [X-ray photorlectron spectroscopy and near-edge X-ray absorption fine structure (NEXAFS)] were used to characterize the electronic and molecular structures of the complexes and the local structure around the copper ion (XAFS) in selected complexes. All complexes showed significant antitumor activity, proving to be more effective than the reference drug cisplatin in a panel of human tumor cell lines, and were able to overcome oxaliplatin and multidrug resistance. Noticeably, these Cu complexes appeared much more effective than cisplatin against 3D spheroids of pancreatic PSN-1 cancer cells; among these, PPh3-containing Cu(I) complex 15 appeared to be the most promising derivative. Mechanistic studies revealed that 15 induced cancer cell death by means of an apoptosis-alternative cell death.

Copper(I) complexes including diimine ligands of the bicinchoninic acid (BCA) and bathocuproinedisulfonic acid (BCS) families and water-soluble phosphines have been synthetized, characterized and investigated for their in vitro anticancer potential against human tumor cell lines representing examples of lung, breast, pancreatic and colon cancers and melanoma. All copper complexes exhibited moderate to high cytotoxic activity and the ability to overcome cisplatin resistance. Remarkably, growth-inhibitory effects evaluated in human non-transformed cells revealed a preferential cytotoxicity versus neoplastic cells. The remarkable cytotoxic effect towards BxPC3 pancreatic cancer cells, notoriously poor sensitive to cisplatin, was not related to a DNA or proteasome damage. Keywords: Copper(I) complexes, Antitumor activity, Diimine ligands, Phosphine ligands, Water soluble

Kiteplatin, [PtCl2(cis-1,4-DACH)] (DACH = diaminocyclohexane), contains an isomeric form of the oxaliplatin diamine ligand trans-1R,2R-DACH and has been proposed as a valuable drug candidate against cisplatin- and oxaliplatin-resistant tumors, in particular, colorectal cancer. To further improve the activity of kiteplatin, it has been transformed into a Pt(IV) prodrug by the addition of two benzoato groups in the axial positions. The new compound, cis,trans,cis-[PtCl2(OBz)2(cis-1,4-DACH)] (1; OBz = benzoate), showed cytotoxic activity at nanomolar concentration against a wide panel of human cancer cell lines. Based on these very promising results, the investigation has been extended to the in vivo activity of compound 1 in a Lewis Lung Carcinoma (LLC) model and its suitability for oral administration. Compound 1 resulted to be remarkably stable in acidic conditions (pH 1.5 to mimic the stomach environment) undergoing a drop of the initial concentration to ~60% of the initial one only after 72 h incubation at 37 °C; thus resulting amenable for oral administration. Interestingly, in a murine model (2·106 LLC cells implanted i.m. into the right hind leg of 8-week old male and female C57BL mice), a comparable reduction of tumor mass (~75%) was observed by administering compound 1 by oral gavage and the standard drug cisplatin by intraperitoneal injection, thus indicating that, indeed, there is the possibility of oral administration for this dibenzoato prodrug of kiteplatin. Moreover, since the mechanism of action of Pt(IV) prodrugs involves an initial activation by chemical reduction to cytotoxic Pt(II) species, the reduction of 1 by two bioreductants (ascorbic acid/sodium ascorbate and glutathione) was investigated resulting to be rather slow (not complete after 120 h incubation at 37 °C). Finally, the neurotoxicity of 1 was evaluated using an in vitro assay.

In the search for new effective metal-based agents to address requirements for anticancer therapy, recent studies demonstrated that copper complexes represent valuable alternatives to currently clinically used Pt(II) drugs.

A series of neutral mixed-ligand [HB(pz)3]Ag(PR3) silver(I) complexes (PR3 = tertiary phosphine, [HB(pz)3]&minus, = 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 thiol-redox homeostasis, and leading to apoptotic cell death. Moreover, for heteroleptic Ag(I) derivatives, an additional ability to damage nuclear DNA has been detected. These results confirm the importance of the type of silver ion coordinating ligands in affecting the biological behavior of the overall corresponding silver complexes, besides in terms of hydrophilic&ndash, lipophilic balance, also in terms of biological mechanism of action, such as interaction with DNA and/or thioredoxin reductase.

Three new 6-methyl-2-oxo-1,2-dihydroquinoline-3-carbaldehyde-thiosemicarbazones-N-4-substituted pro-ligands and their Cu(II) complexes (1, -NH2, 2, -NHMe, 3, -NHEt) have been prepared and characterized. In both the X-ray structures of 1 and 3, two crystallographically independent complex molecules were found that differ either in the nature of weakly metal-binding species (water in 1a and nitrate in 1b) or in the co-ligand (water in 3a and methanol in 3b). Electron Paramagnetic Resonance (EPR) measurements carried out on complexes 1 and 3 confirmed the presence of such different species in the solution. The electrochemical behavior of the pro-ligands and of the complexes was investigated, as well as their biological activity. Complexes 2 and 3 exhibited a high cytotoxicity against human tumor cells and 3D spheroids derived from solid tumors, related to the high cellular uptake. Complexes 2 and 3 also showed a high selectivity towards cancerous cell lines with respect to non-cancerous cell lines and were able to circumvent cisplatin resistance. Via the Transmission Electron Microscopy (TEM) imaging technique, preliminary insights into the biological activity of copper complexes were obtained.

Six platinum(IV) compounds derived from an oxaliplatin analogue containing the unsaturated cyclic diamine trans-1,2-diamino-4-cyclohexene (DACHEX), in place of the 1,2-diaminocyclohexane, and a range of axial ligands, were synthesized and characterized. The derivatives with at least one axial chlorido ligand demonstrated solvent-assisted photoreduction. The electrochemical redox behavior was investigated by cyclic voltammetry, all compounds showed reduction potentials suitable for activation in vivo. X-ray photoelectron spectroscopy (XPS) data indicated an X-ray-induced surface reduction of the Pt(IV) substrates, which correlates with the reduction potentials measured by cyclic voltammetry. The cytotoxic activity was assessed in vitro on a panel of human cancer cell lines, also including oxaliplatin-resistant cancer cells, and compared with that of the reference compounds cisplatin and oxaliplatin, all IC50 values were remarkably lower than those elicited by cisplatin and somewhat lower than those of oxaliplatin. Compared to the other Pt(IV) compounds of the series, the bis-benzoate derivative was by far (5&ndash, 8 times) the most cytotoxic showing that low reduction potential and high lipophilicity are essential for good cytotoxicity. Interestingly, all the complexes proved to be more active than cisplatin and oxaliplatin even in three-dimensional spheroids of A431 human cervical cancer cells.

[Tc-99m][TcN-DBODC(5) is the lead candidate of a class of cationic complexes proposed as myocardial imaging agents (MPIAs). Phase I clinical studies showed that its clinical properties were comparable to those of the commercially available agents. Thus, modification of [Tc-99m]TcN-DBODC(5), directed to obtain an ideal myocardial imaging without interference from the adjacent organ activities, is desirable. This work describes the pharmacological and pharmacokinetic development of four new complexes of general formula [Tc-99m][Tc(N)(DASD)(PNPn)](+), [Tc-99m]TcN-DASD(n) (DASD = 1,4-dioxa-8-azaspiro[4,5]decandithiocarbamate; PNPn = bisphosphinoamine), proposed as improved MPIAs. Among the tested compounds, [Tc-99m]TcN-DASD(5) and [Tc-99m]TcN-DASD(7) showed enhanced heart uptake compared with the gold standards, with a rapid liver washout and superior heart-to-liver ratio. These features might shorten the duration of imaging procedures below 30 min, consenting the early acquisition of high-quality images. In addition, mechanistic studies were performed in cellulo by using human drug-sensitive and drug-resistant cancer cell lines, obtaining results which might be conveniently applied to tumor imaging.

Background: Tyrosine kinase inhibitors (TKI) may offer a normal life expectancy to Chronic Myeloid Leukemia (CML) patients. However, during treatment with nilotinib, a higher than expected incidence of arterial occlusive events (AOEs) was observed. We retrospectively showed an "inflammatory status" during nilotinib treatment that may explain this increased incidence of AOEs. Here, we report results of a prospective multicenter (KIARO) study including 186 CML patients (89 imatinib, 59 nilotinib, 38 dasatinib) in which pro/anti-inflammatory cytokines were measured at diagnosis and during treatment, with the aim to investigate potential changes in each patient's inflammatory status possibly favoring AOEs. Aims: The aims of this study are: 1) to analyze prospectively inflammation status during TKI treatment; 2) to record AOEs; 3) to calculate the SCORE and evaluate its predictive role for AOEs; 4) to analyze possible associations of AOEs with altered inflammation status. Methods: Inflammatory status was evaluated by measuring IL6, IL10, TNFα, oxLDL and hs-CRP plasma levels at diagnosis and during treatment (+1, +3, +6, +12 months); additionally, clinical and biochemical pro-atherothrombotic profiles and the 10-year SCORE chart were also evaluated. Results: 186 newly-diagnosed CML patients starting either imatinib, nilotinib or dasatinib treatment, entered this study. Regarding the inflammation status, we observed that TNFα and IL6 levels were high at diagnosis and decreased during the first 12 months of treatment regardless the type of TKI; instead, IL10 levels were comparable among the 3 TKI cohorts at baseline, but showed a remarkably different evolution during treatment. In fact, IL10 levels were significantly higher after 6 and 12 months of imatinib (p=0.012 and p=0.009, respectively) and dasatinib (p=0.032 and p=0.014, respectively) compared to nilotinib. Consequently, TNFα/IL10 ratio was significantly higher in nilotinib cohort at 6 and 12 months respect to imatinib (p=0.044 at 6 months and p=0.041 at 12 months) and dasatinib (p=0.040 at 6 months and p=0.044 at 12 months). As well, IL6/IL10 ratio was significantly higher in nilotinib cohort compared to imatinib and dasatinib both at 6 (p=0.042 and p=0.049, respectively) and 12 months (p=0.040 and p=0.041, respectively) (Figure 1). OxLDL levels were similar in the 3 groups for the first 6 months. At 12 months we detected a significant increase of oxLDL levels in the nilotinib cohort (p=0.041), respect to imatinib and dasatinib. We did not find significant differences in hs-CRP levels across the 3 TKIs, although a trend for higher levels was observed in nilotinib cohort. Overall, these results suggest a TKI-driven pro-inflammatory status in nilotinib treated patients. After a median follow-up of 23.3 months of TKI treatment, 10 patients (5.4%) suffered an AOE, specifically: 6 ACS, 2 PAOD, 1 TIA and 1 stroke. 5 events (50%) occurred in patients treated with nilotinib, either in first line (4 patients) or in third line (1 patient, after failure following brief treatment with imatinib and dasatinib). In this subgroup of 10 patients experiencing an AOE, we observed a trend of increased IL6 and TNFα median values both at diagnosis and at each time point, compared with the remaining no-AOE patients. IL10 and oxLDL had similar median concentrations in both AOE and no-AOE cohorts, except for oxLDL at 12 months which resulted higher in patients who experienced AOEs. Moreover, regarding AOEs, nilotinib treatment showed a 3.1 times increased risk compared to other TKIs (HR 3.1, 95% CI 2.6-4.4 p< 0.001), whereas 10-year SCORE was not predictive in the whole cohort (HR 0.6, 95% CI 0.33-0.94 p= 0.094) or in any subgroup (imatinib HR 0.8, 95% CI 0.49-1.03 p= 0.067; nilotinib HR 0.4, 95% CI 0.29-0.76 p= 0.112, dasatinib HR 0.6, 95% CI 0.37-0.92 p= 0.082). Conclusions: Our results showed a pro-inflammatory/oxidative milieu increasing along treatment with nilotinib compared with imatinib or dasatinib, as demonstrated by higher IL6/IL10 and TNFα/IL10 ratios, higher levels of oxLDL and a trend for higher hs-CRP only in nilotinib cohort. However, due to the low number of observed events, a formal statistical analysis for any association between AOEs and pro/anti-inflammatory cytokines levels was not possible. Therefore, a longer follow-up is needed to further confirm the active role of nilotinib in AOEs pathogenesis. Figure 1 Figure 1. Disclosures Abruzzese: Incyte: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Bristol Myers Squibb: Consultancy, Honoraria. Galimberti: Incyte: Speakers Bureau; AbbVie, Janssen: Honoraria, Other: Travel grants. Stagno: Pfizer: Consultancy, Honoraria, Other: Support for attending meetings and/or travel; InCyte: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Other: Support for attending meetings and/or travel, Research Funding.

New Pt(II) complexes (Pt-1-3) bearing 1,2,5-oxadiazole ligands (1-3) were synthesized, characterized and evaluated for their ability to disrupt STAT3 dimerization. Ligand 3·HCl showed cytotoxic effects on HCT-116 cells (IC50 = 95.2 μM) and a selective ability to interact with STAT3 (IC50 = 8.2 μM) versus STAT1 (IC50 > 30 μM). Its corresponding platinum complex Pt-3 exhibited an increased cytotoxicity (IC50 = 18.4 μM) and a stronger interaction with STAT3 (IC50 = 1.4 μM), leading to inhibition of its signaling pathway. Pt-3 was also evaluated in cell-based assays for its action on p53 expression and on STAT3 phosphorylation. In syngeneic murine Lewis lung carcinoma (LLC) implanted in C57BL/6 mice, Pt-3 showed a higher antitumor activity with fewer side effects than cisplatin.

Graphical abstract, Highlights • Phthalates and heavy metals are used as technological adjuvants for food packaging. • Phthalates were widely released from any of the assessed pre-packed coffee products. • Also heavy metals were massively released, even exceeding tolerable daily intake. • Concerns about the wide exposure of humans to these pollutants from consumer products., Phthalate plasticizers and heavy metals are widely recognized to be pollutants that interfere with key developmental processes such as masculinization. We investigated the release of phthalates and heavy metals in coffee brewed from coffee packed in single-serve coffee containers made from different types of materials: metal, biodegradable and plastics. We detected with GC–MS small amounts phthalates, below the tolerated daily risks levels, in all the coffees prepared from the different types of capsules. Specifically, Di (2-ethyl-hexyl)-phthalate and DiBP: Diisobuthyl-pthalate were ubiquitously present despite the high variability among the samples (respective range 0.16–1.87 μg/mL and 0.01–0.36 μg/mL). Whereas, diethyl-phthalate (range 0.20–0.26 μg/mL) and di-n-buthyl-phthalate (range 0.02–0.14 μg/mL) were detected respectively in one and three out of the four types of capsule tested. In contrast, we detected by atomic mass spectrometry on mineralized samples heavy metals lead (Pb) and nickel (Ni), in all coffee tested. PB levels (respective range 0.32–211.57 μg/dose) accounted for 42–79%, whereas Ni levels (respective range 166.25–1950.26 μg/dose) accounted for >100% of the tolerable daily intake. These results add to the already present concerns related to the multiple pathways of human exposure and the ubiquitous presence of these pollutants in consumer products and their long-term effect on human health.

Four estrogen-functionalised copper complexes were synthesised and investigated as electrochemical active DNA binding and cleavage agents. These complexes strategically contain a biocompatible metal centre [Cu(II)], a planar aromatic ligand as DNA intercalative agent and an estradiol-derivative moiety which acts as delivery vector to target estrogen-receptor-positive (ER+) cancer cells. Cytotoxic activity was studied over a panel of estrogen-receptor-positive (ER+) and negative (ER−) human cancer cell lines by means of both 2D and 3D cell viability studies. The complexes showed high in vitro intercalative interaction with nuclear DNA and demonstrated to be strong DNA cleaving agents. This series of Cu compounds are potent anticancer agents with low and sub-micromolar IC50 values and the cellular uptake follows the lipophilicity order meaning that the internalisation mainly happened via passive difusion. Finally, the estrogen-complexes are involved in the cellular redox stress by stimulating the production of ROS (reactive oxygen species).

A new family of anticancer compounds has been derived from oxaliplatin by inserting a double-bond between carbons 4 and 5 of the 1,2-diaminocyclohexane ring. Testing against a panel of human tumour cell lines including cervical (A431), ovarian (2008), and colon carcinomas (HCT-15 and LoVo), and two oxaliplatin-resistant clones (LoVo OXP and LoVo MDR) has shown that the new compounds have, in general, equal if not better cytotoxic activity and are able to overcome the oxaliplatin-resistance. Moreover, the oxalato derivative induced lipid droplets increase in LoVo OXP cells thus suggesting the involvement of metabolism stress in its mechanism of action.

The design, synthesis, characterization and biological properties of a Pt(iv) complex containing the very active inhibitor of histone deacetylase (2-propynyl)octanoic acid, POA, as an axial ligand are reported here. The title complex, namely (OC-6-44)-acetatodiamminedichlorido(2-(2-propynyl)octanoato)platinum(iv), 1, containing POA in racemic or in enantiomeric forms, was one/two orders of magnitude more active than cisplatin, depending on the chemo-sensitivity of the cancer cell lines. Moreover, 1 exhibited similar or even better antiproliferative activity than (OC-6-33)-diamminedichloridobis(2-propylpentanoato)platinum(iv), 2, containing two molecules of the well-known histone deacetylase inhibitor 2-propylpentanoic (valproic) acid. The high potency of 1 is likely due to its high cellular accumulation and to the synergism between the DNA-damaging cisplatin and the histone deacetylase inhibitor POA, both released upon the intracellular reduction of 1. Prodrug 1, after oral administration, caused an impressive reduction of the tumor mass (94%) in a model of solid tumor (murine Lewis lung carcinoma), compared to that of the control, whereas (intraperitoneal) cisplatin induced a tumor regression of 75% only. A good accumulation of 1 was observed in the tumor mass. The time course of the body weight attested that cisplatin induced elevated anorexia, whereas treatment with 1 did not induce significant body weight loss throughout the therapeutic experiment.

Novel zwitterionic N-heterocyclic carbenes (NHCs) precursors, 1,3-symmetrically substituted NaHIm1R,3R,4R″ (R = (CH2)3SO3−, R″ = H or CH3), NaHBzim1R,3R (R = (CH2)3SO3−), and 1,3-unsymmetrically substituted NaHIm1R,3R′,4R″ (R = (CH2)3SO3−, R′ = CH2C6H5, R″ = H or CH3), [HBzim1R,3R′]Br (R = (CH2)3SO3Na, R′ = R or CH2C6H5) have been synthesized and used in the synthesis of multicharged silver(I)–NHC complexes. These compounds have been characterized using IR and NMR spectroscopy and by electrospray mass spectrometry. The N-heterocyclic carbene ligand precursor Him1 and the intermediate HBzimPrSO3 were also characterized by X-ray crystallography. Silver(I)-NHCs and the corresponding silver free ligands were assayed for their cytotoxic properties against a panel of human tumour cell lines including lung (A549), colon (HCT-15), breast (MCF-7) and cervical (A431) cancers, along with melanoma (A375). Their antiproliferative activity was further investigated on a human ovarian cell line pair which has been selected for sensitivity/resistance to cisplatin, i.e. 2008/C13* cancer cells. All complexes elicited a similar cytotoxic profile both in cisplatin-sensitive and -resistant cell lines, with resistance factors (R.F.) up to 9 times lower than that of cisplatin, attesting the ability of these derivatives to overcome acquired cisplatin resistance.

Certain metal complexes can have a great antitumor activity, as the use of cisplatin in therapy has been demonstrating for the past fifty years. Copper complexes, in particular, have attracted much attention as an example of anticancer compounds based on an endogenous metal. In this paper we present the synthesis and the activity of a series of copper(II) complexes with variously substituted salicylaldehyde thiosemicarbazone ligands. The in vitro activity of both ligands and copper complexes was assessed on a panel of cell lines (HCT-15, LoVo and LoVo oxaliplatin resistant colon carcinoma, A375 melanoma, BxPC3 and PSN1 pancreatic adenocarcinoma, BCPAP thyroid carcinoma, 2008 ovarian carcinoma, HEK293 non-transformed embryonic kidney), highlighting remarkable activity of the metal complexes, in some cases in the low nanomolar range. The copper(II) complexes were also screened, with good results, against 3D spheroids of colon (HCT-15) and pancreatic (PSN1) cancer cells. Detailed investigations on the mechanism of action of the copper(II) complexes are also reported: they are able to potently inhibit Protein Disulfide Isomerase, a copper-binding protein, that is recently emerging as a new therapeutic target for cancer treatment. Good preliminary results obtained in C57BL mice indicate that this series of metal-based compounds could be a very promising weapon in the fight against cancer.

The huge amount of research into copper(I, II) coordination compounds as anticancer agents has led to the recognition of phosphine copper(I) complexes as a class of very promising anticancer agents. There is growing interest in developing antitumor copper(I) complexes according to the observation that hCTR1, a specific monovalent metal transporter, has been found overexpressed in several cancer cells. The coordination of copper ion with P-donor ligands has allowed copper(I) complexes showing unique stability toward redox disproportionation in aqueous media to be obtained and, by a suitable tailoring of water-soluble phosphines, proper solubility in physiological conditions.

In this paper we report the synthesis and characterization of the complex c,t,c-[Pt(dihydrogenpyrophosphate)(OH)2(cis-1,4-DACH)] (2), a Pt(IV) derivative of kiteplatin, which could be characterized by high bone tropism (due to the pyrophosphate ligand), enough stability to be administered orally, and activatable at the tumor site where the strong reduction conditions can promote its reduction to the corresponding Pt(II) counterpart with known cytotoxic activity. The new complex was characterized by ESI-MS, multinuclear NMR, X-Ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV). 2 is very soluble in aqueous environment, very stable at physiological pH and quite stable also in acidic conditions with the possibility of oral administration. The in vitro cytotoxicity assays, performed against a panel of four human cancer cell lines, have shown that complex 2 has a cytotoxic activity comparable to that of cisplatin and slightly lower than that of kiteplatin and the pyrophosphate Pt(II) precursor. This behavior can be attributed to its reduced ability to enter cancer cells. However, the cytotoxic activity of 2 is very promising considering that generally Pt(IV) complexes have IC50 values greater than those of the Pt(II) counterparts.

Copper(II) complexes of bis(pyrazol-1-yl)- and bis(triazol-1-yl)-acetate heteroscorpionate ligands have been synthesized. The copper(II) complexes [HC(COOH)(pzMe2)2]Cu[HC(COO)(pzMe2)2]&middot, ClO4, [HC(COOH)(pz)2]2Cu(ClO4)2 (pzMe2 = 3,5-dimethylpyrazole, pz = pyrazole) were prepared by the reaction of Cu(ClO4)2&middot, 6H2O with bis(3,5-dimethylpyrazol-1-yl)acetic acid (HC(COOH)(pzMe2)2) and bis(pyrazol-1-yl)acetic acid (HC(COOH)(pz)2) ligands in ethanol solution. The copper(II) complex [HC(COOH)(tz)2]2Cu(ClO4)2&middot, CH3OH (tz = 1,2,4-triazole) was prepared by the reaction of Cu(ClO4)2&middot, 6H2O with bis(1,2,4-triazol-1-yl)acetic acid (HC(COOH)(tz)2) ligand in methanol solution. The synthesized Cu(II) complexes, as well as the corresponding uncoordinated ligands, were evaluated for their cytotoxic activity in monolayer and 3D spheroid cancer cell cultures with different Pt(II)-sensitivity. The results showed that [HC(COOH)(pzMe2)2]Cu[HC(COO)(pzMe2)2]&middot, ClO4 was active against cancer cell lines derived from solid tumors at low IC50 and this effect was retained in the spheroid model. Structure and ultra-structure changes of treated cancer cells analyzed by Transmission Electron Microscopy (TEM) highlighted the induction of a cytoplasmic vacuolization, thus suggesting paraptotic-like cancer cell death triggering.