Exploratory Genome-Wide Association Analysis to Identify Pharmacogenetic Determinants of Response to R-CHOP in Diffuse Large B-Cell Lymphoma

R-CHOP standard chemotherapy is successful in about 60% of diffuse large B-cell lymphoma (DLBCL) patients. Unresponsive patients have a poor prognosis, and predictive biomarkers of response to R-CHOP are lacking. We conducted the first prospective GWAS study aimed at exploring constitutional biomarkers predictive of R-CHOP efficacy and toxicity. Overall, 216 any-stage chemonaïve DLBCL patients candidate to R-CHOP were enrolled. The median age of the 185 eligible patients was 59.2 years, 49.7% were women and 45.4% were stage I-II patients. According to the Revised International Prognostic Index (R-IPI), 14.1%, 56.8% and 29.2% were in the very good, good and poor prognosis groups, respectively. Of the patients, 85.9% produced a complete response. Highly significant associations (i.e., p < 5 × 10^-8) were found between progression-free survival (PFS) and six SNPs (i.e., rs116665727, rs1607795, rs75614943, rs77241831, rs117500207, rs78466241). Additionally, five SNPs (i.e., rs74832512, rs117500207, rs35789195, rs11721010, rs12356569) were highly associated with overall survival (OS). Wild-type patients showed a prolonged PFS or OS compared with patients carrying deleterious alleles (p < 0.001). No association with the adequate significant threshold was observed between SNPs and the objective response or toxicity. In the future, these SNPs, alone or in combination, after a proper validation in an independent cohort, could contribute to improving the prediction of R-CHOP response.

Role of Non-Coding RNAs in Colorectal Cancer: Focus on Long Non-Coding RNAs

Colorectal cancer is one of the most common causes of cancer-related deaths worldwide. Despite the advances in the knowledge of pathogenetic molecular mechanisms and the implementation of more effective drug treatments in recent years, the overall survival rate of patients remains unsatisfactory. The high death rate is mainly due to metastasis of cancer in about half of the cancer patients and the emergence of drug-resistant populations of cancer cells. Improved understanding of cancer molecular biology has highlighted the role of non-coding RNAs (ncRNAs) in colorectal cancer development and evolution. ncRNAs regulate gene expression through various mechanisms, including epigenetic modifications and interactions of long non-coding RNAs (lncRNAs) with both microRNAs (miRNAs) and proteins, and through the action of lncRNAs as miRNA precursors or pseudogenes. LncRNAs can also be detected in the blood and circulating ncRNAs have become a new source of non-invasive cancer biomarkers for the diagnosis and prognosis of colorectal cancer, as well as for predicting the response to drug therapy. In this review, we focus on the role of lncRNAs in colorectal cancer development, progression, and chemoresistance, and as possible therapeutic targets.

Artificial Intelligence Predictive Models of Response to Cytotoxic Chemotherapy Alone or Combined to Targeted Therapy for Metastatic Colorectal Cancer Patients: A Systematic Review and Meta-Analysis

Tailored treatments for metastatic colorectal cancer (mCRC) have not yet completely evolved due to the variety in response to drugs. Therefore, artificial intelligence has been recently used to develop prognostic and predictive models of treatment response (either activity/efficacy or toxicity) to aid in clinical decision making. In this systematic review, we have examined the ability of learning methods to predict response to chemotherapy alone or combined with targeted therapy in mCRC patients by targeting specific narrative publications in Medline up to April 2022 to identify appropriate original scientific articles. After the literature search, 26 original articles met inclusion and exclusion criteria and were included in the study. Our results show that all investigations conducted on this field have provided generally promising results in predicting the response to therapy or toxic side-effects. By a meta-analytic approach we found that the overall weighted means of the area under the receiver operating characteristic (ROC) curve (AUC) were 0.90, 95% C.I. 0.80-0.95 and 0.83, 95% C.I. 0.74-0.89 in training and validation sets, respectively, indicating a good classification performance in discriminating response vs. non-response. The calculation of overall HR indicates that learning models have strong ability to predict improved survival. Lastly, the delta-radiomics and the 74 gene signatures were able to discriminate response vs. non-response by correctly identifying up to 99% of mCRC patients who were responders and up to 100% of patients who were non-responders. Specifically, when we evaluated the predictive models with tests reaching 80% sensitivity (SE) and 90% specificity (SP), the delta radiomics showed an SE of 99% and an SP of 94% in the training set and an SE of 85% and SP of 92 in the test set, whereas for the 74 gene signatures the SE was 97.6% and the SP 100% in the training set.

Pharmacogenetics in diffuse large B-cell lymphoma treated with R-CHOP: Still an unmet challenge

DLBCL is the most common lymphoma representing approximately one third of all non-Hodgkin lymphomas and about 40% of patients do not benefit of the standard first-line immune-chemotherapeutic treatment (i.e., R-CHOP - rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) that is administered as upfront therapy to substantially all patients independently from the stage of disease and other prognostic parameters. The administration of other pharmacological treatments is in fact limited to selected patients, unfitting for R-CHOP. Although clinical prognostic scores, i.e. International Prognostic Index (IPI), and molecular classifiers based on the cell of origin are available, at present no biomarkers predictive of R-CHOP response has been identified and validated. Constitutional polymorphisms of genes involved in the mechanism of action of drugs included in R-CHOP have been suggested by many authors to play a role in the efficacy and in some case in the toxicity of this treatment. Thus, it is conceivable that in the future, after proper validation, some polymorphisms can be used as pharmacogenetic biomarkers of therapeutic outcome in this disease setting. This review discusses the status of the art on molecular biomarkers predictive of DLBCL prognosis and deals with the relevant issue of the variability in response to DLBCL drug treatment. Overall, this review focuses on single nucleotide polymorphisms (SNPs) that, based on a candidate gene approach or on a GWAS analysis, have been suggested to play a role in response to R-CHOP. In particular, SNPs discovered by a candidate gene approach are related to gene involved in drug transport (i.e. ATP-binding cassette transporters), drug metabolism, drug detoxification enzymes, oxidative stress, apoptosis, DNA repair, immunity and angiogenesis. Data from a GWAS analysis performed in DLBCL patients treated with R-CHOP, identified two SNPs associated with clinical outcomes related to genes involved in pivotal cellular processes and in transcriptional regulation and cell cycle progression, respectively. Ongoing prospective pharmacogenetic clinical trials, including a GWAS study we performed, have also been discussed.

Cyclodextrin Inclusion Complexes of Auranofin and Its Iodido Analog: A Chemical and Biological Study

Auranofin (AF) and its iodido analog, i.e., Au(PEt₃) I (AFI), were reported to exhibit very promising anticancer properties both in vitro and in vivo. However, both these gold compounds have a scarce aqueous solubility that hampers their pharmaceutical use. Here, we explore whether encapsulation of these metallodrugs inside hydroxypropyl-beta–cyclodextrin (HPβ–CD) may lead to an improved biopharmaceutical profile for the resulting adducts. Phase solubility studies, performed at 25 °C in an aqueous buffer, revealed, in both cases, the formation of a 1:1 drug to cyclodextrin complex; a far greater apparent stability constant (K_1:1) was measured for AFI compared to AF (331 M⁻¹ versus ca. 30 M⁻¹). NMR studies conducted on the AFI/HPβ–CD system confirmed the formation of a stable 1:1 adduct. Then, binary systems of AF and AFI with HPβ–CD were prepared by colyophilization and characterized by DSC and PXRD. The results revealed the occurrence of drug complexation and/or amorphization for the AFI/HPβ–CD binary system. Afterwards, the antiproliferative properties of the two cyclodextrin adducts and of the corresponding free drugs were comparatively evaluated in vitro in three representative ovarian cancer cell lines, i.e., A2780, SKOV3, and IGROV-1. The results, in all cases, point out that CD complexation of the two gold drugs does not substantially affect their biological activity. The implications of these findings are discussed in the frame of the current knowledge of AF and its analogs.

PNN and KCNQ1OT1 Can Predict the Efficacy of Adjuvant Fluoropyrimidine-Based Chemotherapy in Colorectal Cancer Patients

The benefit of adjuvant chemotherapy in the early stages of colorectal cancer (CRC) is still disappointing and the prediction of treatment outcome quite difficult. Recently, through a transcriptomic approach, we evidenced a role of PNN and KCNQ1OT1 gene expression in predicting response to fluoropyrimidine-based adjuvant chemotherapy in stage III CRC patients. Thus, the aim of this study was to validate in an independent cohort of stages II–III CRC patients our previous findings. PNN and KCNQ1OT1 mRNA expression levels were evaluated in 74 formalin-fixed paraffin-embedded tumor and matched normal mucosa samples obtained by stages II–III CRC patients treated with fluoropyrimidine-based adjuvant chemotherapy. PININ, the protein encoded by PNN, was immunohistochemically evaluated in 15 tumor and corresponding normal mucosa samples, selected on the basis of a low, medium, or high mRNA expression tumor/mucosa ratio. PNN and KCNQ1OT1 mRNA mean expression levels were significantly higher in tumor compared with normal tissues. Patients with high PNN or KCNQ1OT1 tumor mRNA levels according to ROC-based cutoffs showed a shorter disease-free survival (DFS) compared with patients with low tumor mRNA gene expression. Also, patients with tumor mRNA expression values of both genes below the identified cutoffs had a significantly longer DFS compared with patients with the expression of one or both genes above the cutoffs. In a representative large cohort of stages II–III CRC untreated patients retrieved from GEO datasets, no difference in DFS was observed between patients with high and low PNN or KCNQ1OT1 gene expression levels. These data confirm our previous findings and underscore the relevance of PNN and KCNQ1OT1 expression in predicting DFS in early stages of CRC treated with fluoropyrimidine-based adjuvant chemotherapy. If further validated in a prospective case series, both biomarkers could be used to identify patients who benefit from this treatment and to offer alternative chemotherapy regimens to potential unresponsive patients. In relation to the suggested biological role of PNN and KCNQ1OT1 in CRC, they might also be exploited as potential therapeutic targets.

Vinorelbine in Non-Small Cell Lung Cancer: Real-World Data From a Single-Institution Experience

The use of vinorelbine as a single agent or in combination regimens in non-small cell lung cancer (NSCLC) is associated with satisfactory clinical activity. However, the role of vinorelbine-based chemotherapy in chemonaive locally advanced unresectable or metastatic NSCLC patients, according to real-world treatment patterns, has still not been widely explored. Eighty-one patients treated at a single institution were retrospectively analyzed. Thirty-seven received standard first-line single-agent vinorelbine, and 44 received vinorelbine plus platinum drugs, based on physician’s choice; 61.7% were older than 70 years, and 60.5% were affected by ≥2 comorbidities. Sixty-three patients were evaluable for objective response: 22% achieved partial response and 41% stable disease. Median progression-free survival (PFS) was 5.4 months. A benefit in PFS was observed in patients treated with combinations vs. single-agent vinorelbine (6.7 vs. 3.5 months, p = 0.043). Median overall survival (OS) was 10.4 months without a statistically significant difference between treatments (12.4 vs. 7.5 months). In 55 stage IV patients, OS was positively correlated with combination regimens, M1a stage, or ≤2 metastatic lesions. Grade 3–4 toxicity occurred in 33% of patients, and dose reduction in 11%. A statistically significant higher incidence of toxicity was observed in patients receiving combinations, in women, in patients younger than 75 years, or patients with metastases. In this real-word analysis, we confirmed the efficacy and tolerability of vinorelbine as a single agent or combined with platinums in patients usually underrepresented in controlled clinical trials. Single-agent vinorelbine may represent a suitable option in elderly or unfit NSCLC patients and warrants investigation as a potential drug candidate for immunochemotherapy combination regimens.

Structure-activity relationships in a series of auranofin analogues showing remarkable antiproliferative properties

The antiproliferative properties of a series of structurally-related gold(I) and silver(I) linear complexes inspired to the clinically established gold-based drug auranofin were investigated in A2780 ovarian cancer cells and in their auranofin (A2780/AF-R) and cisplatin (A2780/CDDP-R) resistant counterparts. In A2780 cells and in the cisplatin-resistant subline, gold-based analogues manifested a cytotoxicity profile comparable or superior to auranofin, while the silver-based analogues were less active; both gold and silver complexes overcame cisplatin resistance. Yet, a high degree of cross resistance toward gold analogues was noticed in A2780/AF-R cells. In the same cell line cross-resistance for silver analogues was also observed, though lower. All metal complexes were scrutinized for their ability to inhibit thioredoxin reductase (TrxR), the putative primary target for auranofin: overall, gold compounds were more potent TrxR inhibitors than the corresponding silver compounds, probably, as the consequence of the stronger binding of gold to the active site selenocysteine residue. These results highlight that the thiosugar ligand of auranofin is not essential for cytotoxicity while the nature of the metal center (gold/silver) plays a relevant role in its modulation. In addition, a rather clear correlation was found between cytotoxic potency of tested compounds and their ability to inhibit TrxR activity, being gold compounds more effective than silver analogues. However, the residual TrxR activity, measured in A2780 cells treated with the half-maximal inhibitory concentrations of various metal complexes, resulted far higher than expected. These results suggest that additional cytotoxic mechanisms must be operative. The implications of these results are discussed.

RNA sequencing reveals PNN and KCNQ1OT1 as predictive biomarkers of clinical outcome in stage III colorectal cancer patients treated with adjuvant chemotherapy

Five-year overall survival of stage III colorectal cancer (CRC) patients treated with standard adjuvant chemotherapy (ACHT) is highly variable. Genomic biomarkers and/or transcriptomic profiles identified lack of adequate validation. Aim of our study was to identify and validate molecular biomarkers predictive of ACHT response in stage III CRC patients by a transcriptomic approach. From a series of CRC patients who received ACHT, two stage III extreme cohorts (unfavorable vs. favorable prognosis) were selected. RNA-sequencing was performed from fresh frozen explants. Tumors were characterized for somatic mutations. Validation was performed in stage III CRC patients extracted from two GEO datasets. According to disease-free survival (DFS), 108 differentially expressed genes (104/4 up/downregulated in the unfavorable prognosis group) were identified. Among 104 upregulated genes, 42 belonged to olfactory signaling pathways, 62 were classified as pseudogenes (n = 17), uncharacterized noncoding RNA (n = 10), immune response genes (n = 4), microRNA (n = 1), cancer-related genes (n = 14) and cancer-unrelated genes (n = 16). Three out of four down-regulated genes were cancer-related. Mutational status (i.e., RAS, BRAF, PIK3CA) did not differ among the cohorts. In the validation cohort, multivariate analysis showed high PNN and KCNQ1OT1 expression predictive of shorter DFS in ACHT treated patients (p = 0.018 and p = 0.014, respectively); no difference was observed in untreated patients. This is the first study that identifies by a transcriptomic approach and validates PNN and KCNQ1OT1 as molecular biomarkers predictive of chemotherapy response in stage III CRC patients. After a further validation in an independent cohort, PNN and KCNQ1OT1 evaluation could be proposed to prospectively identify stage III CRC patients benefiting from ACHT.

Replacement of the Thiosugar of Auranofin with Iodide Enhances the Anticancer Potency in a Mouse Model of Ovarian Cancer

In recent years, a few successful attempts were made to repurpose the clinically approved antiarthritic gold drug, Auranofin (AF), as an anticancer agent. The present study shows that the iodido(triethylphosphine)gold(I) complex, (Et ₃ PAuI hereafter)-an AF analogue where the thiosugar ligand is simply replaced by one iodide ligand-manifests a solution chemistry resembling that of AF and exerts similar cytotoxic and proapoptotic effects on A2780 human ovarian cancer cells in vitro. However, when evaluated in a preclinical orthotopic model of ovarian cancer, Et ₃ PAuI produces a far superior anticancer action than AF inducing a nearly complete tumor remission. The highly promising in vivo performances here documented for Et ₃ PAuI warrant its further evaluation as a drug candidate for ovarian cancer treatment.

Antiproliferative effects of two gold(I)-N-heterocyclic carbene complexes in A2780 human ovarian cancer cells: a comparative proteomic study

Au(NHC) and Au(NHC)₂, i.e. a monocarbene gold(I) complex and the corresponding bis(carbene) complex, are two structurally related compounds, endowed with cytotoxic properties against several cancer cell lines. Herein, we explore the molecular and cellular mechanisms at the basis of their cytotoxicity in A2780 human ovarian cancer cells. Through a comparative proteomic analysis, we demonstrated that the number of modulated proteins is far larger in Au(NHC)₂-treated than in Au(NHC)-treated A2780 cells. Both gold compounds mainly affected proteins belonging to the following functional classes: protein synthesis, metabolism, cytoskeleton and stress response and chaperones. Particularly, Au(NHC)₂ gave rise to an evident upregulation of several glycolytic enzymes. Moreover, only Au(NHC)₂ triggered a net impairment of respiration and a metabolic shift towards glycolysis, suggesting that mitochondria are relevant cellular targets. We also found that both carbenes, similarly to the gold(I) compound auranofin, caused a strong inhibition of the seleno-enzyme thioredoxin reductase (TrxR). In conclusion, we highlighted that coordination of two carbene ligands to the same gold(I) center greatly enhances the antiproliferative effects of the resulting compound in comparison to the monocarbene derivative. Moreover, TrxR inhibition and metabolic impairment seem to play a major role in the Au(NHC)₂ cytotoxicity. Overall, these antiproliferative effects were also confirmed on other two human ovarian cancer cell lines (i.e. SKOV3 and IGROV1).

Selection and characterization of a human ovarian cancer cell line resistant to auranofin

The anti-arthritic drug auranofin exerts also potent antitumour activity in in vitro and in vivo models, whose mechanisms are not yet well defined. From an auranofin-sensitive human ovarian cancer cell line A2780, a highly resistant (>20-fold) subline (A2780/AF-R) was developed and characterized. Marked reduction of gold accumulation occurred in auranofin-resistant A2780 cells. Also, moderately higher thioredoxin reductase activity in A2780/AF-R cells was observed while no changes in intracellular glutathione content occurred. Resistance to auranofin was associated with a low level of cross-resistance to some investigational gold compounds as well as to oxaliplatin and other anticancer drugs with different mode of action (i.e. melphalan, vinblastine, doxorubicin, etoposide, and paclitaxel). Reduced gold accumulation was associated to substantial gene expression changes in various influx (e.g. SLC22A1, SLC47A1, SLCO1B1) and efflux (e.g. ABCB1, ABCC2, ABCC3) transporters. The expression levels of selected proteins (i.e. SLC22A1, SLC47A1, P-gp) were also changed accordingly. These data provide evidence that multiple drug transporters may act as mediators of transport of auranofin and other gold compounds in cancer cells. Further investigation into the molecular mechanisms mediating transport of auranofin and new gold complexes in view of their potential clinical application in the treatment of cancer is warranted.

The Inhibitory Effects of HYDAMTIQ, a Novel PARP Inhibitor, on Growth in Human Tumor Cell Lines With Defective DNA Damage Response Pathways

The poly(ADP-ribose) polymerase (PARP) enzymes play a key role in the regulation of cellular processes (e.g., DNA damage repair, genomic stability). It has been shown that PARP inhibitors (PARPIs) are selectively cytotoxic against cells having dysfunctions in genes involved in DNA repair mechanisms (synthetic lethality). Drug-induced PARP inhibition potentiates the activity of anticancer drugs such as 5-fluorouracil in enhancing DNA damage, whose repair involves PARP-1 activity. The aim of this study was to evaluate the inhibitory effects of a novel PARPI, HYDAMTIQ, on growth in human tumor cell lines characterized by different features with regard to DNA damage response pathways (BRCA mutational status, microsatellite status, and ATM expression level) and degree of sensitivity/resistance to 5-fluorouracil. HYDAMTIQ showed a more potent inhibitory effect on cell growth in a BRCA2 mutant cell line (CAPAN-1) compared with wild-type cells (C2-6, C2-12, and C2-14 CAPAN-1 clones, and MCF-7). No statistically significant difference was observed after HYDAMTIQ exposure between cells having a different MS status or a different MRE11 mutational status. HYDAMTIQ induced greater antiproliferative effects in SW620 cells expressing a low level of ATM than in H630 cells expressing a high level of ATM. Finally, the combination of HYDAMTIQ and 5-fluorouracil exerted a synergistic effect on the inhibition of SW620 cell growth and an antagonistic effect on that of H630 cell growth. Our results show that the novel PARP inhibitor HYDAMTIQ potently inhibits the growth of human tumor cells with defective DNA damage response pathways and exerts synergistic cytotoxicity in combination with 5-fluorouracil. These data provide relevant examples of synthetic lethality and evidence for further development of this novel PARPI.

Effect of the SOD mimetic MnL4 on in vitro and in vivo oxaliplatin toxicity: Possible aid in chemotherapy induced neuropathy

BACKGROUND

One of the most discomfortable dose-limiting adverse reactions of effective drugs for the treatment of solid tumors is a peripheral neuropathy which is the main reason for dose reduction and discontinuation of the therapy. We identified oxidative stress as one target of oxaliplatin toxicity in the search of possible adjuvant therapies to prevent neuropathy and alleviate pain. Therefore, we studied an effective SOD mimetic compound, MnL4, as a possible adjuvant treatment in in vitro cellular cultures and in vivo on a rat model of oxaliplatin-induced neuropathy.

METHODS AND RESULTS

All rat manipulations were carried out according to the European Community guidelines for animal care. We performed experiments on SH-SY5Y, HT-29 and primary cortical rat astrocytes. Incubation with 100 µM oxaliplatin increased superoxide anion production and caspase 3/7 activity in the neuronal cell line SH-SY5Y and cortical astrocytes. MnL4 (10 µM) significantly reduced the increase in superoxide anion in both cell types, but prevented caspase 3/7 activity only in astrocytes. MnL4 reduced lipid peroxidation induced by oxaliplatin and normalized the intracellular calcium signal evoked by ATP and acetylcholine in astrocytes, preincubated with oxaliplatin. MnL4 did not interfere with the concentration- and time-dependent cytotoxic effects of oxaliplatin on the cancer cell lines HT-29 and LoVo. In vivo MnL4 reduced the response at mechanical noxious and mechanical and thermal non-noxious stimuli in oxaliplatin treated animals. Rat rota-rod performances were improved.

CONCLUSION

Since MnL4 exerts its beneficial effects without interfering with the anticancer activity of oxaliplatin, it could be proposed as adjuvant to prevent and reduce oxaliplatin induced neuropathy.

Proteomic analysis of the cytotoxic effects induced by the organogold(III) complex Aubipyc in cisplatin-resistant A2780 ovarian cancer cells: further evidence for the glycolytic pathway implication

The cellular alterations produced in cisplatin-resistant A2780 ovarian cancer cells (A2780/R) upon treatment with the cytotoxic organogold(III) complex Aubipyc were investigated in depth through a classical proteomic approach. We observed that A2780/R cell exposure to a cytotoxic concentration of Aubipyc for 24 hours results in a conspicuous number of alterations at the protein level that were carefully examined. Notably, we observed that several affected proteins belong to the glucose metabolism system further supporting the idea that the cytotoxic effects of Aubipyc in A2780/R cells are mostly mediated by an impairment of glucose metabolism in excellent agreement with previous observations on the parent cisplatin-sensitive cell line.

Cytotoxic properties of a new organometallic platinum(ii) complex and its gold(i) heterobimetallic derivatives

The high antiproliferative effects of a new organoplatinum(ii) complex are further enhanced upon coordination of a gold(i) phosphane moiety.

In vitro assessment of antibody-conjugated gold nanorods for systemic injections

BACKGROUND

The interest for gold nanorods in biomedical optics is driven by their intense absorbance of near infrared light, their biocompatibility and their potential to reach tumors after systemic administration. Examples of applications include the photoacoustic imaging and the photothermal ablation of cancer. In spite of great current efforts, the selective delivery of gold nanorods to tumors through the bloodstream remains a formidable challenge. Their bio-conjugation with targeting units, and in particular with antibodies, is perceived as a hopeful solution, but the complexity of living organisms complicates the identification of possible obstacles along the way to tumors.

RESULTS

Here, we present a new model of gold nanorods conjugated with anti-cancer antigen 125 (CA125) antibodies, which exhibit high specificity for ovarian cancer cells. We implement a battery of tests in vitro, in order to simulate major nuisances and predict the feasibility of these particles for intravenous injections. We show that parameters like the competition of free CA125 in the bloodstream, which could saturate the probe before arriving at the tumors, the matrix effect and the interference with erythrocytes and phagocytes are uncritical.

CONCLUSIONS

Although some deterioration is detectable, anti-CA125-conjugated gold nanorods retain their functional features after interaction with blood tissue and so represent a powerful candidate to hit ovarian cancer cells.

Proteomic analysis of A2780/S ovarian cancer cell response to the cytotoxic organogold(III) compound Aubipy(c)

Aubipyc is an organogold(III) compound endowed with encouraging anti-proliferative properties in vitro that is being evaluated pre-clinically as a prospective anticancer agent. A classical proteomic approach is exploited here to elucidate the mechanisms of its biological actions in A2780 human ovarian cancer cells. Based on 2-D gel electrophoresis separation and subsequent mass spectrometry identification, a considerable number of differentially expressed proteins were highlighted in A2780 cancer cells treated with Aubipyc. Bioinformatic analysis of the groups of up-regulated and down-regulated proteins pointed out that Aubipyc primarily perturbs mitochondrial processes and the glycolytic pathway. Notably, some major alterations in the glycolytic pathway were validated through Western blot and metabolic investigations.

BIOLOGICAL SIGNIFICANCE

This is the first proteomic analysis regarding Aubipyc cytotoxicity in A2780/S ovarian cancer cell line. Aubipyc is a promising gold(III) compound which manifests an appreciable cytotoxicity toward the cell line A2780, being able to overcome resistance to platinum. The proteomic study revealed for Aubipyc different cellular alterations with respect to cisplatin as well as to other gold compound such as auranofin. Remarkably, the bioinformatic analysis of proteomic data pointed out that Aubipyc treatment affected, directly or indirectly, several glycolytic enzymes. These data suggest a new mechanism of action for this gold drug and might have an impact on the use of gold-based drug in cancer treatment.

Size dependent biological profiles of PEGylated gold nanorods

The interactions with proteins, cytotoxicity and blood compatibility of PEGylated gold nanorods are reviewed as a function of particle size.

Proteomic analysis of ovarian cancer cell responses to cytotoxic gold compounds

Platinum-based chemotherapy is the primary treatment for human ovarian cancer. Overcoming platinum resistance has become a critical issue in the current chemotherapeutic strategies of ovarian cancer as drug resistance is the main reason for treatment failure. Cytotoxic gold compounds hold great promise to reach this goal; however, their modes of action are still largely unknown. To shed light on the underlying molecular mechanisms, we performed 2-DE and MS analysis to identify differential protein expression in a cisplatin-resistant human ovarian cancer cell line (A2780/R) following treatment with two representative gold compounds, namely Auranofin and Auoxo6. It is shown that Auranofin mainly acts by altering the expression of Proteasome proteins while Auoxo6 mostly modifies proteins related to mRNA splicing, trafficking and stability. We also found that Thioredoxin-like protein 1 expression is greatly reduced after treatment with both gold compounds. These results are highly indicative of the likely sites of action of the two tested gold drugs and of the affected cellular functions. The implications of the obtained results are thoroughly discussed in the frame of current knowledge on cytotoxic gold agents.

Gold(III) complexes with 2-substituted pyridines as experimental anticancer agents: solution behavior, reactions with model proteins, antiproliferative properties

Gold(III) compounds form a family of promising cytotoxic and potentially anticancer agents that are currently undergoing intense preclinical investigations. Four recently synthesized and characterized gold(III) derivatives of 2-substituted pyridines are evaluated here for their biological and pharmacological behavior. These include two cationic adducts with 2-pyridinyl-oxazolines, [Au(pyox(R))Cl(2)][PF(6)], [pyox(R)=(S)-4-benzyl-2-(pyridin-2-yl)-4,5-dihydrooxazole, I; (S)-4-iso-propyl-2-(pyridin-2-yl)-4,5-dihydrooxazole, II] and two neutral complexes [Au(N,N'OH)Cl(2)], III, and [Au(N,N',O)Cl], IV, containing the deprotonated ligand N-(1-hydroxy-3-iso-propyl-2-yl)pyridine-2-carboxamide, N,N'H,OH, resulting from ring opening of bound pyox(R) ligand of complex II by hydroxide ions. The solution behavior of these compounds was analyzed. These behave as classical prodrugs: activation of the metal center typically takes place through release of the labile chloride ligands while the rest of the molecule is not altered; alternatively, activation may occur through gold(III) reduction. All compounds react eagerly with the model protein cyt c leading to extensive protein metalation. ESI MS experiments revealed details of gold-cyt c interactions and allowed us to establish the nature of protein bound metal containing fragments. The different behavior displayed by I and II compared to III and IV is highlighted. Remarkable cytotoxic properties, against the reference human ovarian carcinoma cell lines A2780/S and A2780/R were disclosed for all tested compounds with IC(50) values ranging from 1.43 to 6.18 μM in the sensitive cell line and from 1.59 to 10.86 μM in the resistant one. The common ability of these compounds to overcome cisplatin resistance is highlighted. The obtained results are thoroughly discussed in the frame of current knowledge on cytotoxic gold compounds.

Overcoming tumor multidrug resistance using drugs able to evade P-glycoprotein or to exploit its expression

Multidrug resistance (MDR) is a major obstacle to the effective treatment of cancer. Cellular overproduction of P-glycoprotein (P-gp), which acts as an efflux pump for various anticancer drugs (e.g. anthracyclines, Vinca alkaloids, taxanes, epipodophyllotoxins, and some of the newer antitumor drugs) is one of the more relevant mechanisms underlying MDR. P-gp belongs to the superfamily of ATP-binding cassette transporters and is encoded by the ABCB1 gene. Its overexpression in cancer cells has become a therapeutic target for circumventing MDR. As an alternative to the classical pharmacological strategy of the coadministration of pump inhibitors and cytotoxic substrates of P-gp and to other approaches applied in experimental tumor models (e.g. P-gp-targeting antibodies, ABCB1 gene silencing strategies, and transcriptional modulators) and in the clinical setting (e.g. incapsulation of P-gp substrate anticancer drugs into liposomes or nanoparticles), a more intriguing strategy for circumventing MDR is represented by the development of new anticancer drugs which are not substrates of P-gp (e.g. epothilones, second- and third-generation taxanes and other microtubule modulators, topoisomerase inhibitors). Some of these drugs have already been tested in clinical trials and, in most of cases, show relevant activity in patients previously treated with anticancer agents which are substrates of P-gp. Of these drugs, ixabepilone, an epothilone, was approved in the United States for the treatment of breast cancer patients pretreated with an anthracycline and a taxane. Another innovative approach is the use of molecules whose activity takes advantage of the overexpression of P-gp. The possibility of overcoming MDR using the latter two approaches is reviewed herein. 

Genomic and genetic alterations influence the progression of gastric cancer

Gastric cancer is one of the leading causes of cancer-related deaths worldwide, although the incidence has gradually decreased in many Western countries. Two main gastric cancer histotypes, intestinal and diffuse, are recognised. Although most of the described genetic alterations have been observed in both types, different genetic pathways have been hypothesized. Genetic and epigenetic events, including 1q loss of heterozygosity (LOH), microsatellite instability and hypermethylation, have mostly been reported in intestinal-type gastric carcinoma and its precursor lesions, whereas 17p LOH, mutation or loss of E-cadherin are more often implicated in the development of diffuse-type gastric cancer. In this review, we summarize the sometimes contradictory findings regarding those markers which influence the progression of gastric adenocarcinoma.

Gold compounds as anticancer agents: chemistry, cellular pharmacology, and preclinical studies

Gold compounds are a class of metallodrugs with great potential for cancer treatment. During the last two decades, a large variety of gold(I) and gold(III) compounds are reported to possess relevant antiproliferative properties in vitro against selected human tumor cell lines, qualifying themselves as excellent candidates for further pharmacological evaluation. The unique chemical properties of the gold center confer very interesting and innovative pharmacological profiles to gold-based metallodrugs. The primary goal of this review is to define the state of the art of preclinical studies on anticancer gold compounds, carried out either in vitro or in vivo. The available investigations of anticancer gold compounds are analyzed in detail, and particular attention is devoted to underlying molecular mechanisms. Notably, a few biophysical studies reveal that the interactions of cytotoxic gold compounds with DNA are generally far weaker than those of platinum drugs, implying the occurrence of a substantially different mode of action. A variety of alternative mechanisms were thus proposed, of which those involving either direct mitochondrial damage or proteasome inhibition or modulation of specific kinases are now highly credited. The overall perspectives on the development of gold compounds as effective anticancer drugs with an innovative mechanism of action are critically discussed on the basis of the available experimental evidence.

Cellular pharmacology of gemcitabine

Gemcitabine (2',2'-difluoro 2'-deoxycytidine, dFdC) is the most important cytidine analogue developed since cytosine arabinoside (Ara-C). The evidence of its potent antitumor activity in a wide spectrum of in vitro and in vivo tumor models has been successfully confirmed in the clinical setting. Despite structural and pharmacological similarities to Ara-C, gemcitabine displays distinctive features of cellular pharmacology, metabolism and mechanism of action. Following influx through the cell membrane via nucleoside transporters, gemcitabine undergoes complex intracellular conversion to the nucleotides gemcitabine diphosphate (dFdCDP) and triphosphate (dFdCTP) responsible for its cytotoxic actions. The cytotoxic activity of gemcitabine may be the result of several actions on DNA synthesis. dFdCTP competes with deoxycytidine triphosphate (dCTP) as an inhibitor of DNA polymerase. dFdCDP is a potent inhibitor of ribonucleoside reductase, resulting in depletion of deoxyribonucleotide pools necessary for DNA synthesis and, thereby potentiating the effects of dFdCTP. dFdCTP is incorporated into DNA and after the incorporation of one more nucleotide leads to DNA strand termination. This extra nucleotide may be important in hiding the dFdCTP from DNA repair enzymes, as incorporation of dFdCTP into DNA appears to be resistant to the normal mechanisms of DNA repair. Gemcitabine can be effectively inactivated mainly by the action of deoxycytidine deaminase to 2,2'-difluorodeoxyuridine. Also, 5'-nucleotidase opposes the action of nucleoside kinases by catalysing the conversion of nucleotides back to nucleosides. Additional sites of action and self-potentiating effects have been described. Evidence that up- or down-regulation of the multiple membrane transporters, target enzymes, enzymes involved in the metabolism of gemcitabine and alterations in the apoptotic pathways may confer sensitivity/resistance to this drug, has been provided in experimental models and more recently also in the clinical setting. Synergism between gemcitabine and several other antineoplastic agents has been demonstrated in experimental models based on specific pharmacodynamic interactions. Knowledge of gemcitabine cellular pharmacology and its molecular mechanisms of resistance and drug interaction may thus be pivotal to a more rational clinical use of this drug in combination regimens and in tailored therapy.

Molecular characterization of established human colon carcinoma cell lines (HCT-8) made resistant to 5-fluorouracil by different selection schedules

To provide some insight into molecular mechanisms of 5 fluorouracil (5-FU) clinical resistance in colorectal cancer, we hypothesized that different in vitro exposure schedules of human colorectal cancer cell lines mimicking clinical infusion or bolus regimens could lead to differential gene expression. Resistant HCT-8 colon cancer cell lines (HCT-8/FUI/15R and HCT-8/FUB/2R) were selected from parental sensitive HCT-8 cells by long-term and short-term exposure schedules, respectively. Expression levels of the 437 genes evaluated by the Atlas Select cDNA Expression Human Tumor Array were not substantially different between HCT-8/FUB/2R and HCT-8 cell lines except for three genes downregulated in the resistant subline. Several genes were differentially expressed in HCT-8/FUI/15R cells compared to the parental cell line: 43 genes, including three chemoresistance-related genes, were upregulated, and three genes were downregulated. HCT-8/FUB/2R cells were substantially more resistant to 5-FU in comparison to HCT-8/FUI/15R cells after both 4- and 72-h exposures. No substantial differences were observed among resistant and parental cells in sensitivity to SN-38, the active metabolite of irinotecan, and oxaliplatin. Analysis of the mRNA levels of thymidylate synthase, thymidine phosphorylase, and bcl-2 genes evaluated by reverse transcription and real time PCR (RT-PCR) assay showed comparable results in resistant sublines and sensitive parental cells, whereas expression of the dihydropyrimidine dehydrogenase gene was markedly increased in both resistant cell lines compared to parental cells.

Pharmacological strategies for overcoming multidrug resistance

Multidrug resistance (MDR) is a major obstacle to the effective treatment of cancer. One of the underlying mechanisms of MDR is cellular overproduction of P-glycoprotein (P-gp) which acts as an efflux pump for various anticancer drugs. P-gp is encoded by the MDR1 gene and its overexpression in cancer cells has become a therapeutic target for circumventing multidrug resistance. A potential strategy is to co-administer efflux pump inhibitors, although such reversal agents might actually increase the side effects of chemotherapy by blocking physiological anticancer drug efflux from normal cells. Although many efforts to overcome MDR have been made using first and second generation reversal agents comprising drugs already in current clinical use for other indications (e.g. verapamil, cyclosporine A, quinidine) or analogues of the first-generation drugs (e.g. dexverapamil, valspodar, cinchonine), few significant advances have been made. Clinical trials with third generation modulators (e.g. biricodar, zosuquidar, and laniquidar) specifically developed for MDR reversal are ongoing. The results however are not encouraging and it may be that the perfect reverser does not exist. Other approaches to multidrug resistance reversal have also been considered: encapsulation of anthracyclines in liposomes or other carriers which deliver these drugs selectively to tumor tissues, the use of P-gp targeted antibodies such as UIC2 or the use of antisense strategies targeting the MDR1 messenger RNA. More recently, the development of transcriptional regulators appears promising. Also anticancer drugs that belong structurally to classes of drugs extruded from cells by P-gp but that are not substrates of this drug transporter may act as potent inhibitors of MDR tumors (e.g. epothilones, second generation taxanes). Taking advantage of MDR has also been studied. Bone marrow suppression, one of the major side effects of cancer chemotherapy, can compromise the potential of curative and palliative chemotherapy. It is conceivable that drug resistance gene transfer into bone marrow stem cells may be able to reduce or abolish chemotherapy-induced myelosuppression and facilitate the use of high dose chemotherapy. Clinical trials of retroviral vectors containing drug resistance genes have established that the approach is safe and are now being designed to address the therapeutically relevant issues.

Relationships between promoter polymorphisms in the thymidylate synthase gene and mRNA levels in colorectal cancers

Thymidylate synthase (TS) intratumoural expression may be a prognostic marker and predict outcome of 5-fluorouracil (5-FU)-based chemotherapy in colorectal cancer patients. The TS gene promoter enhancer region contains two different polymorphisms which can influence TS mRNA transcriptional and translational efficiency: a polymorphic tandem repeat sequence (2 or 3 repeats; 2R and 3R) and a single nucleotide polymorphism (SNP), G > C, within the second repeat of the 3R alleles. We studied the relationship between tumoural TS mRNA expression levels and TS gene polymorphisms in the colonic mucosa of 48 colorectal cancer patients. The 3R/3R genotype was characterised by higher TS mRNA levels in the tumour than the 2R/2R-2R/3R genotypes (P = 0.071). Regarding the relationship with the SNP polymorphism, a statistically significant difference in TS gene expression between the 3RG/3RG genotype and 2R/2R-2R/3RC-2R/3RG genotype subset was observed (P = 0.017). No statistically significant correlation was observed between experimental data and baseline clinical-pathological characteristics as well as clinical outcome in the relatively small patient series investigated. This is the first study reporting an association between the TS intra-repeat SNP and gene expression levels in colorectal cancer patients. These results suggest that in 3R/3R patients, the G > C polymorphism may be an important factor in determining TS mRNA expression levels, and warrant further investigation of the role of TS promoter polymorphisms as predictors of sensitivity to 5-FU-based chemotherapy in larger case series.

In vitro antiproliferative activity against human colon cancer cell lines of representative 4-thiazolidinones. Part I

The characterization of two cyclooxygenase isoforms (COX), the rate-limiting enzyme for the synthesis of prostaglandins (PGs) from arachidonic acid, has allowed the development of COX-2 selective inhibitors as non-steroidal anti-inflammatory drugs (NSAIDs) with significant gastric tolerability. However, PGs are also important in cancer pathogenesis. Thus, there is an increasing interest in studying COX-2 inhibitors as potential drugs aimed at the prevention and treatment of cancer, especially colorectal cancer. The purpose of this study was to determine the inhibitory effects of some representative 4-thiazolidinones, already widely investigated as potential NSAIDs, on the growth of five human colon carcinoma cell lines with a different COX-2 expression, and to correlate them with COX-2 inhibitory properties. Our results preliminarily revealed that 2-phenylimino derivative 3 and 2,4-thiazolidindione 4 were the most active compounds. In particular, 3 mainly inhibited the HT29 cell line characterized by a high COX-2 expression, whereas 4 showed antiproliferative properties on all tested cell lines, suggesting molecular targets other than COX-2 inhibition.

In vitro activity of vinorelbine on human leukemia cells

Vinorelbine (VNR) is a semi-synthetic Vinca rosea alkaloid that has been employed both as a single agent and in combination, and has shown significant antitumor activity. As little is known about VNR activity on human leukemia, we studied its in vitro cytotoxic effect on human leukemia cell lines (FLG 29.1, HL60, K562, Balm 4, CEM and Daudi) and on fresh leukemia cells from 28 patients: 2 acute myeloid leukemia (AML); 3 chronic myeloid leukemia in blastic phase (CML-BP); 5 acute lymphoblastic leukemia (ALL); 18 B-chronic lymphatic leukemia (B-CLL), employing the colorimetric INT assay and determining the IC50. We observed that VNR exerts its cytotoxic activity on leukemic cell lines in a dose-dependent fashion. The lymphoid cell lines appear more sensitive than the myeloid ones to the VNR-dependent growth inhibition. A similar pattern was noticed for leukemia cells in primary cultures. VNR is not effective on CML-BP cells, shows variable activity on the AML and ALL cells and is very effective against B-CLL cells. VNR inhibited the growth of fresh B-CLL cells from 15 of 18 patients, the IC50 doses ranging from 4 ng/ml to 83 microg/ml (doses coinciding with the plasma levels obtained in clinics). These observations strongly suggest that VNR could be useful in clinics for the treatment of B-CLL.

Activity of vinorelbine on B-chronic lymphocytic leukemia cells in vitro

Vinorelbine (VNR) is a new semi-synthetic Vinca rosea alkaloid that has been employed both in combination and as a single agent, showing a significant antitumour activity. Since little is known about VNR in human leukemia, we studied the in vitro cytotoxic effect of VNR on peripheral blood lymphocytes from 18 patients affected by B-chronic lymphocytic leukemia (CLL), employing the INT assay. VNR inhibited fresh B-CLL cells from 15/18 patients in primary cultures, the ID50 doses ranging from 4 ng/ml to 83 micrograms/ml. These data strongly suggest that VNR could be effective in the treatment of B-CLL.