Retention rate of tumor necrosis factor inhibitors, anti-interleukin 17, and anti-interleukin 12/23 drugs in a single-center cohort of psoriatic arthritis patients.

The objective of this study was to evaluate biological disease-modifying anti-rheumatic drugs (bDMARDs) survival in several therapy courses of patients affected by psoriatic arthritis (PsA) and to compare tumor necrosis factor inhibitors (TNFi) and non-TNFi retention rates. A total of 241 bDMARD therapy courses (155 TNFi drugs, 65 anti-interleukin (IL)-17 drugs, and 21 anti-IL12/23) were analyzed. Bivariate analyses were performed to assess the presence of demographic and clinical features, as well as comorbidities, associated with bDMARD discontinuation in TNFi and non-TNFi groups. In the bivariate analyses of TNFi and non-TNFi groups, we found a lower age at the start of TNFi therapy in the former group [46 years, interquartile range (IQR) 45-54 vs 50.5 years, IQR 42-61; p=0.004] as well as a lower proportion of patients with skin psoriasis (65.8% vs 88.4%; p<0.001). Survival analysis showed no significant differences between TNFi and non-TNFi groups. Cox regression found fibromyalgia as a predictor of drug failure [hazard ratio (HR) 3.40, confidence interval (CI) 1.92-6.03; p<0.001] and first-line bDMARDs as a protective factor (HR 0.46, CI 0.25-0.88; p=0.019). Lastly, among TNFi courses, fibromyalgia was associated with drug suspension (HR 6.52, CI 3.16-13.46; p<0.001), while only a trend of significance for skin psoriasis as a risk factor for drug failure was shown (HR 2.38, CI 1.00-5.66, p=0.05). This study provides information about clinical and demographic factors associated with retention rates of bDMARDs from a real-life, single-center cohort of PsA patients.

The Italian Society for Rheumatology clinical practice guidelines for the diagnosis and management of fibromyalgia Best practices based on current scientific evidence.

Fibromyalgia or fibromyalgia syndrome (FMS) is defined as a central sensitization syndrome characterized by the dysfunction of neurocircuits detecting, transmitting and processing nociceptive stimuli; the prevalent manifestation is musculoskeletal pain. In addition to pain, there are multiple accompanying symptoms, in common with other algo-dysfunctional syndromes, which are reflected in a broad spectrum of somatic, neurocognitive and neuro-vegetative manifestations. An evidence-based approach is essential in FMS management, in order to improve patient health and to reduce its social burden. Since in the last ten years new international guidelines for clinical practice (Clinical Practice Guidelines or CPGs) concerning FMS diagnosis and pharmacological/ non-pharmacological management have been published, the Italian Society of Rheumatology (SIR) has decided to adapt them to the Italian national setting. The framework of the Guidelines International Network Adaptation Working Group was adopted to identify, appraise (AGREE II), synthesize, and customize the most recent CPGs on FMS to the needs of the Italian healthcare context. A working group of rheumatologists from SIR epidemiology unit and FMS experts identified relevant clinical questions to guide the systematic review of the literature. The target audience of these CPGs included physicians and healthcare professionals who manage FMS. The adapted recommendations were finally assessed by an external multidisciplinary panel. From the systematic search in databases (Pubmed/Medline, Embase) and grey literature, 6 CPGs were selected and appraised by two independent raters. The combination of the scientific evidence underlying the original CPGs with expert opinion lead to the development of 17 recommendations. The quality of evidence for each recommendation was reported and their potential impact on clinical practice was assessed. These SIR recommendations are expected to be a valuable aid in the diagnosis and treatment of FMS, as they will contribute to disseminate the best practice on the basis of the current scientific evidence.

Tumor induced osteomalacia: A single center experience on 17 patients.

Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome due to a phosphaturic tumor, which overproduces Fibroblast Growth Factor 23 (FGF-23), causing hyperphosphaturia, hypophosphatemia, low 1,25(OH)2D and osteomalacia. Tumor localization is critical, diagnostic delay ranges from 2.5 to 28 years and to date surgical removal is considered effective treatment. We retrospectively evaluated patients with definite diagnosis of TIO referred to a tertiary Rheumatology Center between September 2000 and May 2020, investigating clinical management and disease outcome. We included 17 patients: 10 (58.8%) were females, mean age at diagnosis was 55.3 ± 13.9 years (mean ± standard deviation), with a diagnostic delay from symptoms onset to tumor detection of 6.6 ± 6.25 years. Biochemical data were: serum phosphorus 1.3 ± 0.4 mg/dL (Reference Range: 2.5-4.6), serum 1,25(OH)2D 31.8 ± 22.9 ng/mL (RR: 25-86), intact FGF-23, 358.9 ± 677 pg/mL (RR: 25-45); 24 h-Urine Phosphorus was increased in only 2 patients, while tubular reabsorption of phosphate (TRP) was decreased in all patients confirming a renal phosphate wasting. In 2013 68Ga- DOTA-based PET/CT was introduced in routinely practice and diagnostic delay was consistently reduced (from 8.6 ± 7.9 to 4.3 ± 2.4 years). Thirteen patients underwent surgery, one patient underwent radiofrequency ablation; 3 patients, not eligible for surgery, were treated only with supplements of phosphorus and calcitriol. One was started on Burosumab after several unsuccessful surgical attempts. After surgery or ablation, 8 patients had complete remission, 3 TIO persistence, and 3 had overtime relapse. Relapses were observed only in patients who previously underwent closed biopsy. To our knowledge, this is the widest European cohort of TIO patients in the last two decades. We confirm a usual diagnostic delay and recommend a stepwise diagnostic approach. Tumor biopsy is not recommended due to the potential cell spilling. Surgery is generally considered a definitive treatment, even though other approaches have been successful in curing TIO. Active surveillance on possible recurrence is always needed. Burosumab appears a promising therapy.

Use of licap and ltap flaps for breast reconstruction.

Breast conserving surgery has been reserved for patients with favorable proportion between tumor dimensions and breast size. Introduction of local flaps from the lateral thoracic region has widened the indications for breast conserving surgery, by allowing surgeons to perform wider excisions, thus yet be able to ensure tumor-free surgical margins and a good aesthetic result. We have used lateral intercostal perforator flaps and flaps harvested on the lateral thoracic artery and lateral thoracic artery axial flap in patients with small breasts and an unfavorable tumor to breast size proportion. From May 2015 to October 2016, 19 patients with breast tumors have been treated with BCS and immediate volume replacement reconstruction by pedicle perforator flaps from the lateral thoracic region. In 15 patients lateral intercostal artery perforator flaps or lateral thoracic artery perforator flaps were used after quadrantectomy or wide local excision, in 3 patients as volume replacement after mastectomy and in 1 patient after mastectomy following previous augmentation mammoplasty. In all patients, good breast symmetry was achieved, with no major complications. Fibrosis of the flap and residual breast parenchyma, with volume reduction were noticed after postoperative radiotherapy in thin patients or flaps with little subcutaneous fat. Perforator flaps from the lateral thoracic region should become the gold standard for reconstructions after breast conserving surgery involving less than 20% of the breast volume or after mastectomy in patients with small breasts. The operating procedure is safe, quick and allows sparing of the latissimus dorsi muscle and thus minimal donor site morbidity, as well as an excellent aesthetic result.

PATIENT SATISFACTION AFTER BREAST RECONSTRUCTION: IMPLANTS VS. AUTOLOGOUS TISSUES.

INTRODUCTION: Breast reconstruction is increasingly present in the treatment of breast cancer. It may be accomplished with implants or autologous tissues. This cross-sectional study evaluates patients satisfaction and quality of life in women after successful autologous or implant breast reconstruction. MATERIAL AND METHODS: 109 women who successfully underwent breast reconstruction between 2007 and 2016 were included. The patients completed the BREAST-Q questionnaire at follow-up visits. Additional data were collected retrospectively from the hospital charts regarding complications, smoking, chemotherapy, radiotherapy, unilateral or bilateral reconstruction, BMI and comorbidities. Mann-Whitney U Test was applied to evaluate differences between the autologous breast reconstruction group (n = 50) and the implant breast reconstruction group (n = 59). RESULTS: Women with a successful autologous reconstruction were significantly more satisfied with their reconstructed breasts than women with successful alloplastic breast reconstruction as measured by the BREAST-Q breasts module (p = 0. 00596), psycho-social well-being module (p=0.04) and sexual well-being module (p=0.00068). Furthermore, there is a higher degree of satisfaction in patients who have not undergone radiotherapy, with no complications and with a normal BMI for implant reconstruction group as well as in non-smokers, and bilateral reconstructions for flap reconstruction group. DISCUSSION: The findings of our study are in agreement with the data found in the literature, attributing greater satisfaction with physical, mental and social wellbeing, as well as with elements having repercussion on sexual wellbeing, to autologous breast reconstruction. CONCLUSIONS: Autologous breast reconstruction leads to higher patient satisfaction than implant breast reconstruction. This study may help patients and medical teams in their decision-making process regarding breast reconstruction. This pilot study opens several questions that need further investigations in a larger prospective studyKeywords: Breast reconstruction, breast-Q, satisfaction, implant, autologous tissue.

CD99 regulates neural differentiation of Ewing sarcoma cells through miR-34a-Notch-mediated control of NF-κB signaling.

Sarcomas are mesenchymal tumors characterized by blocked differentiation process. In Ewing sarcoma (EWS) both CD99 and EWS-FLI1 concur to oncogenesis and inhibition of differentiation. Here, we demonstrate that uncoupling CD99 from EWS-FLI1 by silencing the former, nuclear factor-κB (NF-κB) signaling is inhibited and the neural differentiation program is re-established. NF-κB inhibition passes through miR-34a-mediated repression of Notch pathway. CD99 counteracts EWS-FLI1 in controlling NF-κB signaling through the miR-34a, which is increased and secreted into exosomes released by CD99-silenced EWS cells. Delivery of exosomes from CD99-silenced cells was sufficient to induce neural differentiation in recipient EWS cells through miR-34a inhibition of Notch-NF-κB signaling. Notably, even the partial delivery of CD99 small interfering RNA may have a broad effect on the entire tumor cell population owing to the spread operated by their miR-34a-enriched exosomes, a feature opening to a new therapeutic option.

Lifestyle and dietary habits of patients with gout followed in rheumatology settings.

Diet and lifestyles modification are core aspects of the non-pharmacological management of gout, but a poor consistency with suggested guidelines is reported. This study aimed to investigate dietary and lifestyle habits of patients with gout followed in rheumatology settings. Data were retrieved from the baseline dataset of the KING study, a multicentre cohort study of patients with gout followed in rheumatology settings. Dietary habits were assessed with the Italian National Institute of Statistics (ISTAT) food-frequency questionnaire and compared with reported data about general population. The relative increase of exposure was estimated by standardized prevalence ratios adjusted for gender, age and geographical distribution. The study population included 446 patients, with a mean age of 63.9 years and a M/F ratio of 9:1. Compared to the Italian population, gouty patients showed a higher prevalence of obesity [1.82 (1.52-2.18)] and a higher consumption of wine [1.85 (1.48-2.32)] and beer [2.21 (1.68-2.90)], but a lower prevalence of smoking and a lower intake of liquor. They showed a lower intake of red meat [0.80 (0.71-0.91)], but a similar intake of other tested dietary factors. Gouty patients' lifestyle is still partially different from the recommended.

Prognostic significance of miR-34a in Ewing sarcoma is associated with cyclin D1 and ki-67 expression.

BACKGROUND: At diagnosis, identification of reliable biological indicators of prognosis to allow stratification of patients according to different risks is an important but still unresolved aspect in the treatment of Ewing sarcoma (EWS) patients. This study aimed to explore the role of miR-34A expression on prognosis of EWS patients. PATIENTS AND METHODS: Specimens from 109 patients with non-metastatic EWS treated at the Rizzoli Institute with neoadjuvant chemotherapy (protocols ISG/SSGIII, EW-1, EW-2, EW-REN2, EW-REN3, EW-PILOT) and 17 metastases were studied. Sixty-eight patients (62%) remained disease-free and 41 (38%) relapsed (median follow-up: 67 months, range 9-241 months). Expression of miR-34a and of some of its targets (cyclin D1, bcl-2, SIRT1 and YY1) was evaluated by qRT-PCR using TaqMan MicroRNA Assays and/or by immunohistochemistry on tissue microarrays from the same patients. RESULTS: High expression of miR-34a in localized tumors was significantly related to better event-free and overall survival (P = 0.004). Relevance of miR-34a was confirmed by using different calibrators (normal mesenchymal stem cells and different normal tissues). By multivariate Cox regression analysis, low miR-34a expression as well as nontotal necrosis and high levels of lactate dehydrogenase were all confirmed as independent risk factors associated with poor outcome. Expression of miR-34a was lower in metastases than in primary tumors. It inversely correlated with expression of cyclin D1 and Ki-67. CONCLUSIONS: By demonstrating its relationship with clinical outcome, we propose evaluation of miR-34a at diagnosis of EWS patients to allow early risk stratification. Validation of these results would nonetheless ultimately need a prospective assessment.

A clinical overview of bone marrow edema.

Bone marrow edema (BME) is a descriptive term which identifies a specific magnetic resonance imaging (MRI) pattern that can be observed in a number of clinical entities, which are often characterized by pain as their main symptom, but show significant differences in terms of histopathological findings, causal mechanisms and prognosis. Bone marrow lesions in the subchondral bone of subjects with knee osteoarthritis (OA) seem to be associated with pain and progression of cartilage damage over time. Some histopathological studies of advanced OA have shown a prevalent fibrosis and bone marrow necrosis. BME of the subchondral bone in rheumatoid arthritis is associated with an infiltrate of inflammatory cells and osteoclasts and has a predictive value of further development of erosions. In spondyloarthritis, BME of the sacroiliac joints identifies an active sacroiliitis and is associated with histological inflammation and radiographic progression, whereas the relationship between BME lesions of the spine and syndesmophyte development is still controversial. BME syndromes (BMES), such as transient osteoporosis of the hip, regional migratory osteoporosis, and transient post-traumatic BMES, are characterized by a BME pattern on MRI and a self-limiting course. The potential evolution of BMES toward osteonecrosis is still controversial.

CD99 suppresses osteosarcoma cell migration through inhibition of ROCK2 activity.

CD99, a transmembrane protein encoded by MIC2 gene is involved in multiple cellular events including cell adhesion and migration, apoptosis, cell differentiation and regulation of protein trafficking either in physiological or pathological conditions. In osteosarcoma, CD99 is expressed at low levels and functions as a tumour suppressor. The full-length protein (CD99wt) and the short-form harbouring a deletion in the intracytoplasmic domain (CD99sh) have been associated with distinct functional outcomes with respect to tumour malignancy. In this study, we especially evaluated modulation of cell-cell contacts, reorganisation of the actin cytoskeleton and modulation of signalling pathways by comparing osteosarcoma cells characterised by different metastasis capabilities and CD99 expression, to identify molecular mechanisms responsible for metastasis. Our data indicate that forced expression of CD99wt induces recruitment of N-cadherin and ß-catenin to adherens junctions. In addition, transfection of CD99wt inhibits the expression of several molecules crucial to the remodelling of the actin cytoskeleton, such as ACTR2, ARPC1A, Rho-associated, coiled-coil containing protein kinase 2 (ROCK2) as well as ezrin, an ezrin/radixin/moesin family member that has been clearly associated with tumour progression and metastatic spread in osteosarcoma. Functional studies point to ROCK2 as a crucial intracellular mediator regulating osteosarcoma migration. By maintaining c-Src in an inactive conformation, CD99wt inhibits ROCK2 signalling and this leads to ezrin decrease at cell membrane while N-cadherin and ß-catenin translocate to the plasma membrane and function as main molecular bridges for actin cytoskeleton. Taken together, we propose that the re-expression of CD99wt, which is generally present in osteoblasts but lost in osteosarcoma, through inhibition of c-Src and ROCK2 activity, manages to increase contact strength and reactivate stop-migration signals that counteract the otherwise dominant promigratory action of ezrin in osteosarcoma cells.

Italian Society for Rheumatology recommendations for the management of hand osteoarthritis.

Hand osteoarthritis (OA) is a common and potentially disabling disease, with different features from hip and knee OA so that a specific therapeutic approach is required. Evidence based recommendations for the management of hand OA were developed by the European League Against Rheumatism (EULAR) in 2006. The Italian Society for Rheumatology (SIR) aimed to update, adapt to national contest and disseminate the EULAR recommendations for the management of hand OA. The multidisciplinary group of experts included specialists involved in the management of patients with hand OA. In order to maintain consistency with EULAR recommendations, a similar methodology was utilized by the Italian group. The original propositions were reformulated in terms of a search query and for every recommendation a systematic search was conducted updating EULAR recommendations' review. The propositions were translated in Italian and reformulated basing on collected evidences and expert opinion. The strength of recommendation was measured for each proposition with the EULAR ordinal and visual analogue scales. The original 11 propositions of EULAR recommendations were translated and adapted to Italian context. Further evidences were collected about non-pharmacological therapies, local treatments, intra-articular injection with SYSADOA and corticosteroids, and surgery. The SIR has developed updated recommendations for the management of hand OA adapted to the Italian healthcare system. Their implementation in clinical practice is expected to improve the management of patients with hand OA.

Italian Society of Rheumatology recommendations for the management of gout.

OBJECTIVE: Gout is the most common arthritis in adults. Despite the availability of valid therapeutic options, the management of patients with gout is still suboptimal. The Italian Society of Rheumatology (SIR) aimed to update, adapt to national contest and disseminate the 2006 EULAR recommendations for the management of gout. METHODS: The multidisciplinary group of experts included rheumatologists, general practitioners, internists, geriatricians, nephrologists, cardiologists and evidence-based medicine experts. To maintain consistency with EULAR recommendations, a similar methodology was utilized by the Italian group. The original propositions were translated in Italian and priority research queries were identified through a Delphi consensus approach. A systematic search was conducted for selected queries. Efficacy and safety data on drugs reported in RCTs were combined in a meta-analysis where feasible. The strength of recommendation was measured by utilising the EULAR ordinal and visual analogue scales. RESULTS: The original 12 propositions were translated and adapted to Italian context. Further evidences were collected about the role of diet in the non-pharmacological treatment of gout and the efficacy of oral corticosteroids and low-dose colchicine in the management of acute attacks. Statements concerning uricosuric treatments were withdrawn and replaced with a proposition focused on a new urate lowering agent, febuxostat. A research agenda was developed to identify topics still not adequately investigated concerning the management of gout. CONCLUSIONS: The SIR has developed updated recommendations for the management of gout adapted to the Italian healthcare system. Their implementation in clinical practice is expected to improve the management of patients with gout.

Efficacy of and resistance to anti-IGF-1R therapies in Ewing's sarcoma is dependent on insulin receptor signaling.

Identification of patient selection criteria and understanding of the potential mechanisms involved in the development of resistance are crucial for an appropriate and successful design of clinical trials with anti-insulin-like growth factor (IGF)-1R therapies. Few Ewing's sarcomas are highly sensitive to IGF-1R targeting and understanding the reason why, may hold the secret to improve successful treatments. In this paper, we show that a major mechanism of resistance to highly specific inhibitors of IGF-1R, either antibodies or tyrosine kinase inhibitors may involve enhanced insulin receptor (IR)-A homodimer formation and IGF-2 production. Resistant cells are able to switch from IGF-1/IGF-1R to IGF-2/IR-A dependency to maintain sustained activation of AKT and ERK1/2, proliferation, migration and metastasis. These cells also showed higher proliferative response to insulin, in keeping with a switch towards insulin pathways sustaining proliferation and malignancy, rather than metabolism. Our findings demonstrate a role for IR-A in eliciting intrinsic and adaptive resistance to anti-IGF-1R therapies. Thus, we indicate that tumors with low IGF-1R:IR ratio are unlikely to greatly benefit from anti-IGF-1R therapies and that the efficacy of anti-IGF-1R therapies should be evaluated in relationship to the IR-A:IGF-1R ratio in cancer cells. Moreover, we provide evidences supporting IR-A as an important target in sarcoma therapy.

Osteoporosis with vertebral fractures in young males, due to bone marrow mastocytosis: a report of two cases.

Male osteoporosis in young patients is an unusual condition, always worth investigating as a possible manifestation of secondary osteoporosis. Mastocytosis is a clonal disorder of mast cells with heterogeneous presentations; when pathologic cells accumulate only in the bone marrow, vertebral fractures and systemic osteoporosis may represent the sole clinical presentation at the onset of the disease. We report on two young male patients who came to our attention because of multiple dorsal and lumbar vertebral fractures, with no other signs of systemic mastocytosis (SM). Lumbar and femoral dual x-ray absorptiometry showed reduced bone mineral density values; biochemical investigations did not report significant anomalies, suggestive of secondary osteoporosis. One of the patients underwent iliac crest bone biopsy, which was not diagnostic. A vertebral intralesional CT-guided bone biopsy was performed in both patients, which allowed the diagnosis of SM. Our experience pointed out that bone biopsy still remains the gold standard for the diagnosis of SM. However, iliac crest biopsy can be not significant because of circumscribed bone marrow involvement: in these cases only intralesional bone biopsy could be diagnostic.

Clinical impact of the methotrexate resistance-associated genes C-MYC and dihydrofolate reductase (DHFR) in high-grade osteosarcoma.

BACKGROUND: Aims of this study were the validation of C-MYC involvement in methotrexate (MTX) resistance and the assessment of clinical impact of C-MYC and dihydrofolate reductase (DHFR) in osteosarcoma (OS). MATERIALS AND METHODS: The involvement of C-MYC in MTX resistance was validated with an antisense approach. C-MYC and DHFR protein levels at diagnosis were assessed by immunohistochemistry on series of patients treated with either a MTX-based protocol (IOR/OS-1; 72 patients) or with a standard four-drug regimen (ISG/SSG 1; 61 patients). RESULTS: Down-regulation of C-MYC significantly decreased the MTX resistance level of OS cells, demonstrating its causal involvement in this phenomenon. In clinical samples, a worse outcome was associated with increased levels of DHFR and C-MYC at diagnosis in the IOR/OS-1 patients and of C-MYC in the ISG/SSG 1 patients. CONCLUSIONS: Meanwhile the adverse clinical impact of DHFR overexpression appeared to be closely related to the relevance of MTX in the chemotherapeutic protocol, that of C-MYC overexpression was more general and not strictly MTX related. The assessment of C-MYC and DHFR at diagnosis, together with that of other known prognostic markers, can be considered for an early identification of subgroups of OS patients with higher risk of adverse outcome.

CD99 isoforms dictate opposite functions in tumour malignancy and metastases by activating or repressing c-Src kinase activity.

CD99 gene encodes two distinct proteins, produced by alternative splicing of CD99 gene transcript. Full-length CD99 isoform (CD99wt) is formed by an extracellular domain, followed by a transmembrane domain and a 36 amino-acid intracytoplasmic domain, which is partially deleted in the truncated, short form (CD99sh). A differential expression of these two CD99 molecules can lead to distinct functional outcomes in lymphocytes. To investigate the functional effects of CD99 molecules on malignancy, forced overexpression of the two CD99 isoforms was induced in osteosarcoma and prostate cancer cells. The two isoforms exhibited opposite functions: the major form dramatically inhibits anchorage-independent growth, anoikis resistance, migration and metastasis, whereas the CD99sh remarkably favours the phenomena. A mechanistic analysis of CD99-transfected osteosarcoma cells points to involvement of c-Src family kinase activity in regulating CD99 functions in malignancy. Ser168 residue of CD99 plays a pivotal role in the reversion of the malignant phenotype. Our findings highlight the involvement of CD99 in crucial processes of cancer malignancy, serving as a curtain raiser for this, so far neglected molecule. In addition, a dualistic role for the two CD99 isoforms was shown in agreement with what was observed for other cell adhesion molecules.

RNA interference as a key to knockdown overexpressed cyclooxygenase-2 gene in tumour cells.

Silencing those genes that are overexpressed in cancer and contribute to the survival and progression of tumour cells is the aim of several researches. Cyclooxygenase-2 (COX-2) is one of the most intensively studied genes since it is overexpressed in most tumours, mainly in colon cancer. The use of specific COX-2 inhibitors to treat colon cancer has generated great enthusiasm. Yet, the side effects of some inhibitors emerging during long-term treatment have caused much concern. Genes silencing by RNA interference (RNAi) has led to new directions in the field of experimental oncology. In this study, we detected sequences directed against COX-2 mRNA, that potently downregulate COX-2 gene expression and inhibit phorbol 12-myristate 13-acetate-induced angiogenesis in vitro in a specific, nontoxic manner. Moreover, we found that the insertion of a specific cassette carrying anti-COX-2 short hairpin RNA sequence into a viral vector (pSUPER.retro) greatly increased silencing potency in a colon cancer cell line (HT29) without activating any interferon response. Phenotypically, COX-2 deficient HT29 cells showed a significant impairment of their in vitro malignant behaviour. Thus, the retroviral approach enhancing COX-2 knockdown, mediated by RNAi, proved to be an useful tool to better understand the role of COX-2 in colon cancer. Furthermore, the higher infection efficiency we observed in tumour cells, if compared to normal endothelial cells, may disclose the possibility to specifically treat tumour cells without impairing endothelial COX-2 activity.

The molecular mechanisms responsible for resistance to ET-743 (Trabectidin; Yondelis) in the Ewing's sarcoma cell line, TC-71.

Identification of new active agents against sarcoma is considered an important challenge in medical oncology. ET-743 (Trabectidin; Yondelis) has recently emerged as the first active drug developed against sarcoma in the last two decades, with promising results especially against soft-tissue sarcoma and Ewing's sarcoma (ES). In this study, we analyzed the molecular mechanisms responsible for resistance to ET-743 in ES cells. Three resistant cell variants (TC/ET 3 nM, TC/ET 6 nM and TC/ET 12 nM) were obtained, showing 28-, 47- and 102-fold increase in ET-743 resistance. Cross-resistance to other drugs was analyzed. Comparative genomic hybridization and cDNA microarray technology were employed to characterize and compare the gene expression profile of two TC/ET variants with the parental cell line. TC/ET cells show a conventional multidrug resistance phenotype and P-glycoprotein overexpression was found to significantly contribute to ET-743 resistance. However, functional studies with the cyclosporine analogue, PSC-833, indicate that other mechanisms are involved in resistance to ET-743. The gene expression profile of TC/ET cells indicated, among up-regulated genes, an increase in expression of insulin-like growth factor receptor-I (IGF-IR) and one of its major intracellular mediators, insulin receptor substrate-1. Functional studies using a neutralizing antibody anti-IGF-IR confirmed involvement of this signaling pathway in resistance to ET-743. Simultaneous blockage of both P-glycoprotein and IGF-IR completely restored sensitivity to ET-743 in ES cells. Overall, these findings provide impetus for future studies testing the therapeutic value of new specific inhibitors of P-glycoprotein and IGF-IR, which could represent a concrete therapeutic option for ES patients refractory to conventional agents.

Reversal of multidrug-resistance using Valspodar (PSC 833) and doxorubicin in osteosarcoma.

High-grade osteosarcoma is an extremely aggressive neoplasm, where over 80% of patients present with life-threatening micrometastases at diagnosis. Systemic control of the disease is therefore critical for the treatment of these patients and neoadjuvant chemotherapy using various drugs, including doxorubicin (DXR), which has been demonstrated to be the most effective regimen. Multidrug resistance (MDR) to some anticancer agents, including DXR, mediated by the MDR1 gene product P-glycoprotein (Pgp), has been shown to be a major cause of chemotherapy failure in osteosarcoma. We analyzed the effect of a cyclosporine A derivate Valspodar (PSC 833) on MDR human osteosarcoma cells. We also evaluated Pgp expression in sporadic appendicular canine osteosarcoma. Moreover, dogs were treated with combined administration of DXR and PSC 833. Several blood samples were collected for the determination of DXR and PSC 833 levels. PSC 833 induced a complete reversal of the resistant phenotype at concentrations compatible with the clinical use. Pgp was present in 12/18 (66.6%) of the cases. At the time of DXR administration, adequate blood concentrations of PSC 833, to provide a complete MDR reversal, were obtained without clinical or laboratory findings of toxicity. Combination therapy with DXR and PSC 833 allowed a 30% decrease in DXR dose infusion with equivalent therapeutic exposure. The high incidence of Pgp expression in osteosarcoma confers to the study a rationale for an effective regimen based on down-modulation of MDR.

Effectiveness of Type I interferons in the treatment of multidrug resistant osteosarcoma cells.

P-glycoprotein overexpression is an important adverse prognostic marker for osteosarcoma (OS) patients, which is associated with higher risk for developing metastases as a consequence of the limited responsiveness to standard treatments of P-glycoprotein overexpressing OS cells. The use of cytokines has been advocated as a possible therapeutic approach to overcome multidrug resistance (MDR), being active on cell lines that are resistant to conventional drugs. In this study, we evaluated in vitro effects of interferons (IFNs) on MDR P-glycoprotein overexpressing OS cells. Type I IFNs, but not IFNgamma, showed tangible inhibitory effects on OS cell growth, which were higher in MDR cell lines compared to parental cells. The higher sensitivity of P-glycoprotein overexpressing cells to Type I IFNs correlates with higher expression of the activator of the transcription (STAT)-2 and (STAT)-3, two intracellular mediators of the IFNalpha and IFNbeta signaling pathways, whereas no differences were observed with respect to the expression or activation of the Type I IFN receptor and STAT-1. Exposure of OS MDR cells to Type I IFN decreased the expression of P-glycoprotein. This effect resulted in a significantly increased chemosensitivity of MDR cells to doxorubicin. Therefore, our data support the use of IFNalpha or IFNbeta in the treatment of osteosarcoma patients who overexpress P-glycoprotein in their primary tumors, and respond insufficiently to current therapeutic regimens.