Inhibition of p85, the non-catalytic subunit of phosphatidylinositol 3-kinase, exerts potent antitumor activity in human breast cancer cells

The phosphoinositide 3-kinases (PI3Ks) are heterodimers consisting of the catalytic subunit p110 and the regulatory subunit p85. The PI3K/Akt pathway is strongly deregulated in breast cancer (BC) representing one of the mechanisms of resistance to therapies. Therefore, the identification of inhibitors of PI3K components represents one of the main goals to produce therapeutic agents. Here, we evaluated the efficacy of a phosphopeptide 1257 (P-1257) that targeting p85 strongly inhibits PI3K activity. We tested the effects of P-1257 administration in vitro and in vivo using BC cells expressing different levels of ErbB-2 and resistant or responsive to Trastuzumab. We demonstrated that inhibition of p85 activity by P-1257 induces cell death and sensitizes JIMT-1 and KPL-4 ErbB-2-overexpressing BC cells to Trastuzumab treatment. It is noteworthy that P-1257 delivery in vivo by electroporation or liposomes significantly inhibits the proliferation of tumor cells engrafted at subcutaneous and visceral sites. Overall, our data indicate that the p85 subunit is a valid target for therapeutic approaches and suggest that the structure of the peptide used in our study could be utilized for the development of novel drugs to apply in combination with therapies that fail to cure BCs with high PI3K activity.

SCCA-IC serum levels are predictive of clinical response in HCV chronic hepatitis to antiviral therapy: a multicentric prospective study

The combination of pegylated interferon (Peg-IFN) and ribavirin is currently the gold standard therapy in patients with HCV chronic infection. The duration of therapy, as well as the therapeutic dosage, depend on the genotype. Identification of the genotype and rapid virological response (RVR) are widely accepted as the most important predictors of clinical outcome during antiviral therapy but to optimize cost-benefits and to reduce possible side effects, further prognostic factors are needed. Squamous cell carcinoma antigens immunocomplex (SCCA-IC) has been reported to be increased in the serum of patients with liver cancer. In this multicentric prospective study, we investigated the serum levels of SCCA-IC in 103 patients with HCV chronic infection. Serum HCV-RNA was detected before the beginning of treatment, after 4, 12, 24 or 48 weeks, and at week 24 during follow-up. RVR, early virological response and sustained virological response (SVR) were assessed following the international guidelines. SCCA-IC levels were higher in responders (238 AU, interquartile difference 130-556 AU) and decreased significantly to 125 AU (70-290 AU). The mean baseline value in nonresponders was 149 AU (86.5-306.5 AU), but after 4 weeks of treatment the serum levels decreased to 115 AU (80-280 AU): the profile of reduction was different between patients with or without a positive SVR. Logistic regression with SVR as dependent variable identified as significant independent variables: the reduction in SCCA-IC after 1 month (OR = 4.82; 95% CI 1.39-16.67; P = 0.131) and a genotype other than 1 (OR = 0.094; 95% CI 0.21-0.42; P = 0.002); sex and age were also significant factors influencing SVR. SCCA-IC seems to be a reliable independent prognostic marker of therapeutic effectiveness in anti-HCV positive patients undergoing antiviral therapy.

Thymosin alpha-1 with peginterferon alfa-2a/ribavirin for chronic hepatitis C not responsive to IFN/ribavirin: an adjuvant role?

This study was conducted to determine whether the adding thymosin alpha-1 to standard of care for re-treatment of nonresponding hepatitis C infections can improve sustained viral response (SVR) rates. Patients (n = 552) with hepatitis C infections not responding to the combination of Peginterferon alfa-2a or 2b with ribavirin (RBV)were randomized to receive peginterferon alfa-2a 180 mg/week with RBV 800-1200 mg/daily plus either thymosin alpha-1 1.6 mg SC twice weekly (n = 275) or placebo (n = 277) for 48 weeks. Eighty-eight per cent of patients had HCV genotype 1, 6.6% type 4, 2.2% type 2 and 3.6% type 3. SVR rates in the intention to treat population were similar between thymosin alpha-1 and placebo (12.7%vs 10.5%; P = 0.407). Among patients who completed all 48 weeks of therapy, the SVR rate was significantly higher in the thymosin alpha-1 group at 41.0% (34/83) compared with 26.3% (26/99) in the placebo group (P = 0.048). No significant difference was observed between treatment groups in the incidence of adverse events. The addition of thymosin alpha-1 to the standard of care did not increase the on-treatment HCV viral response. Thymosin alpha-1 seems to play no role in the primary therapy of the disease. This study raises the hypothesis that thymosin alpha-1 may have a secondary therapeutic role as an adjuvant in the prevention of relapses in patients achieving a virologic response during therapy.

Outcome of advanced NSCLC patients harboring sensitizing EGFR mutations randomized to EGFR tyrosine kinase inhibitors or chemotherapy as first-line treatment: a meta-analysis

BACKGROUND

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI) are effective as first-line treatment of advanced non-small-cell lung cancer patients with EGFR mutations (EGFR-M+).

PATIENTS AND METHODS

We conducted a literature-based meta-analysis to quantify the magnitude of benefit with upfront EGFR TKI in EGFR-M+ patients. Meta-regression and sensitivity analyses were also carried out to identify additional predictors of outcome and to assess the influence of trial design.

RESULTS

Five trials (805 patients) were identified (three trials prospectively enrolling EGFR-M+ patients and two retrospective analyses of EGFR-M+ patients). TKI significantly increased progression-free survival (PFS) [hazard ratio (HR) 0.45, 95% confidence interval (CI) 0.36-0.58, P < 0.0001] and overall response rate (ORR) (HR 2.08, 95% CI 1.75-2.46, P < 0.0001)] over chemotherapy, while significantly decreasing neutropenia. No significant difference was observed in overall survival. The rate of exon-19 mutations, female gender, and nonsmoking status were identified as additional predictors of outcome at meta-regression analysis. A significant interaction with trial design was found for both PFS (P = 0.028) and ORR (P = 0.008), suggesting a larger advantage for patients treated within prospective trials.

CONCLUSIONS

In EGFR-M+ patients, first-line TKI increase both PFS and ORR by ~25%, while significantly decreasing toxicity. The role of additional predictive factors and the influence of trial design on the magnitude of the observed benefit warrant further investigation.

The mTOR pathway: a new target in cancer therapy

Mammalian target of rapamycin (mTOR) is a key protein kinase controlling signal transduction from various growth factors and upstream proteins to the level of mRNA translation and ribosome biogenesis, with pivotal regulatory effects on cell cycle progression, cellular proliferation and growth, autophagy and angiogenesis. The mTOR pathway, and its upstream regulators in the PI3K/PTEN/AKT cascade, are altered in a variety of experimental and human malignancies.This has led to the prediction that mTOR inhibitors may be used as anticancer agents. With the recent approval of two mTOR-targeted drugs (temsirolimus and everolimus) for the treatment of renal cell carcinoma and mantle cell lymphoma, this paradigm has been effectively translated into the clinical setting. In this review, we discuss mTOR biology and regulation, the mode of action of mTOR inhibitors as anti-cancer agents, and current clinical evidence supporting the use of rapamycin-like mTOR inhibitors in cancer treatment.

Preliminary results of phase II study of capecitabine and gemcitabine (CAP-GEM) in patients with metastatic pretreated thymic epithelial tumors (TETs)

BACKGROUND

No previous prospective trials have been reported with capecitabine and gemcitabine (CAP-GEM) in patients with metastatic thymic epithelial tumors (TETs). We conducted a multicenter study to determine the activity and tolerability of this regimen in pretreated TETs.

PATIENTS AND METHODS

A total of 15 patients were enrolled in the first stage of phase II study. All patients received CAP-GEM every 3 weeks. The primary end point was objective response rate (RR); secondary end points were toxicity, progression-free survival (PFS) and overall survival.

RESULTS

Complete responses (CR) and partial responses were observed in three (20%) and three (20%) patients for a 40% RR, respectively. Grade 1-2 neutropenia, anemia and thrombocytopenia were the most common side-effects, noted in seven (46.7%), five (33.3%) and five (33.3%) patients, respectively. The most common grade 3 toxicity was neutropenia in three patients (20%). Median PFS was 11 months (95% confidence interval 4-17). The 1- and 2-year survival rates were 80% and 67%, respectively.

CONCLUSION

We have decided to publish the preliminary results because this regimen was more active than that expected. Although our results are preliminary, CAP-GEM shows activity and safety in pretreated TETs. Furthermore, multicenter trials, also in first-line setting, are necessary to confirm our results.

Human Mena (hMena), estrogen receptor-β (ER-β), and epidermal growth factor receptor (EGFR) expression as prognostic factors in node-negative non-small-cell lung cancer (NSCLC)

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Background: hMena is a cytoskeleton regulatory protein involved in adhesion and cell motility, particularly in response to EGFR activation. In addition, a possible correlation between ER-β and EGFR expression has been recently suggested in NSCLC. We therefore investigated the potential relationship and prognostic value of hMena, ER-β, and EGFR expression in node-negative NSCLC patients (pts) who underwent surgery at our institution. Methods: hMena, ER-β (isoforms 1, 2), and EGFR expression, analyzed on Tissue Micro Array, were correlated to disease-free, cancer-specific, and overall survival (DFS/CSS/OS) using a Cox model including sex, stage, age, grading, histology, number of resected nodes (RN). Logistic and generalized linear models were used to evaluate predictors of significant Cox-model variables. Receiver Operative Curve (ROC) analysis identified optimal cutoff values. Internal cross-validation (100 simulations with 80% of the dataset) was accomplished. Results: 248 pts were gathered (median follow-up 26 months, range 1–75; male/female 71/29%; adeno/other 43/57%; grading G1–2/G3 45/55%; Stage I/II 82/8%; RN ≤10/>10 34/66%). Multivariate analysis, highlighting the prognostic role of RN and hMena, is shown in the table . ER-β/2 and EGFR strongly predicted hMena overexpression (p=0.009, p=0.01); indeed, when hMena was removed from the multivariate model, both factors were independent predictors of DFS/CSS. Cross-validation analysis confirmed the prognostic role of hMena with a replication rate of 43/66% for DFS/CSS. Conclusions: hMena expression is prognostic in early NSCLC undergoing curative surgery. ER-β/2 and EGFR strongly correlate with hMena status and their prognostic role deserves further investigation.

[Table: see text]

No significant financial relationships to disclose.

Short-term (ST) versus long-term (LT) hormone treatment (HT) in combination with radiotherapy (RT) for locally advanced prostate cancer (LAPC): Meta-analysis of randomized trials (RCTs)

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Background: Hormone suppression plus RT is able to significantly decrease the recurrences and the mortality of patients (pts) affected by LAPC. In order to determine if difference exists between ST-HT (HT ≤6 months), and LT-HT (HT ≥8 months) in combination with RT for LAPC, a literature-based meta-analysis was conducted. Methods: Event-based relative risks (RR) with 95% confidence intervals (CI) were derived through a random-effect model. Differences in primary (biochemical failure, BF, and cancer-specific survival, CSS), and secondary outcomes (overall survival, OS, and pattern of recurrence, local or distant, LR/DM) were explored. Absolute differences (AD) and the number of patients needed to treat (NNT) were calculated. Heterogeneity test, a meta-regression analysis with clinico-pathological predictors for outcomes and a correlation analysis for surrogate end-points were conducted as well. Results: Four trials (3,148 patients) were gathered. Data were available for all RCTs only for BF; patient population ranged from 297 to 1,521 pts. Three predictors were identified: median PSA (range 9.5–20.35), Gleason score 7–10 (27–55% pts/trial) and T3–4 (13–77% pts/trial). None of the selected predictors did significantly affect any outcomes. A significant correlation and trend between the log of the BF-RR and DM and OS were found (p=0.029 and p=0.07, respectively). Conclusions: Although with significant heterogeneity (reflecting different patient’ risk stratifications), LT-HT seems to significantly decrease biochemical, local and distant recurrences, and increase cancer specific survival in comparison with ST-HT. Balancing these advantages with toxicities and costs represents the next step of the current analysis.

[Table: see text]

No significant financial relationships to disclose.

Magnitude of benefit of the addition of bevacizumab (BEVA) to first-line chemotherapy (CT) for advanced/metastatic colorectal cancer (MCRC): Meta-analysis of randomized clinical trials

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Background: The monoclonal antibody against vascular endothelial growth factor BEVA has recently demonstrated to improve survival for MRC patients (pts). Nevertheless, the magnitude of the provided benefit in the daily practice is still controversial. In order to quantify the benefit of adding BEVA to CT for MCRC, a literature-based meta-analysis was conducted. Methods: Survival Hazard Ratios (HR) were extracted from prospective, randomized clinical trials (RCTs, either phase II/III) reports. HR and event-based relative risks (RR) with 95% confidence intervals (CI) were derived through a random-effect model. Differences in primary (progression-free- and overall-survival, PFS/OS) and secondary outcomes (overall, partial and complete response rates, ORR/PR/CR) were explored. Absolute differences (AD) and the number of patients needed to treat (NNT) were calculated. Heterogeneity test and a meta-regression analysis with clinical predictors for outcomes were conducted as well. A sensitivity analysis according to the trial phase-design was accomplished. Results: Five trials (2,728 pts), 2 phase II (313 pts) and 3 phase III (2,415 pts), were gathered. No significant interaction was found in the sensitivity analysis between phase II and III, although a trend showed a better PFS results for BEVA in phase II trials (p=0.057). At the meta-regression analysis female gender and rectal primary site were significant predictors for PFS (p=0.003, p=0.005). Toxicity analysis is ongoing. Conclusions: Although concerns regarding costs and toxicities still exist, BEVA significantly improves the outcome of untreated MCRC pts. The absolute benefit provided into an unselected population for molecular features should be considered of paramount importance for advanced disease.

[Table: see text]

No significant financial relationships to disclose.

Targeting the leukemic stem cell: the Holy Grail of leukemia therapy

Since the discovery of leukemic stem cells (LSCs) over a decade ago, many of their critical biological properties have been elucidated, including their distinct replicative properties, cell surface phenotypes, their increased resistance to chemotherapeutic drugs and the involvement of growth-promoting chromosomal translocations. Of particular importance is their ability to transfer malignancy to non-obese diabetic-severe combined immunodeficient (NOD-SCID) mice. Furthermore, numerous studies demonstrate that acute myeloid leukemia arises from mutations at the level of stem cell, and chronic myeloid leukemia is also a stem cell disease. In this review, we will evaluate the main characteristics of LSCs elucidated in several well-documented leukemias. In addition, we will discuss points of therapeutic intervention. Promising therapeutic approaches include the targeting of key signal transduction pathways (for example, PI3K, Rac and Wnt) with small-molecule inhibitors and specific cell surface molecules (for example, CD33, CD44 and CD123), with effective cytotoxic antibodies. Also, statins, which are already widely therapeutically used for a variety of diseases, show potential in targeting LSCs. In addition, drugs that inhibit ATP-binding cassette transporter proteins are being extensively studied, as they are important in drug resistance-a frequent characteristic of LSCs. Although the specific targeting of LSCs is a relatively new field, it is a highly promising battleground that may reveal the Holy Grail of cancer therapy.