Gian Carlo Antonini Cappellini

Sequential Treatment with Ipilimumab and BRAF Inhibitors in Patients With Metastatic Melanoma: Data From the Italian Cohort of the Ipilimumab Expanded Access Program

Of 93 patients with pretreated, BRAFV600 mutation-positive advanced melanoma who received vemurafenib or dabrafenib before (n = 45) or after (n = 48) treatment with ipilimumab 3 mg/kg, median overall survival (mOS) from first treatment was 9.9 and 14.5 months, respectively. Among patients treated with a BRAF inhibitor first, mOS from the end of BRAF inhibition was 1.2 months for those who did not complete ipilimumab treatment as per protocol, compared with 12.7 months for those who did (p < .001). Prospective, randomized studies are required to determine the optimal sequencing of ipilimumab and BRAF inhibitors in patients with BRAF-mutated metastatic melanoma.

High Expression of the Mismatch Repair Protein MSH6 Is Associated With Poor Patient Survival in Melanoma

OBJECTIVES The outcome of patients with primary melanoma (PM) cannot be completely explained based on currently adopted clinical-histopathologic criteria. In this study, we evaluated the potential prognostic value of mismatch repair protein expression in PMs. METHODS We examined the immunohistochemical staining of mismatch repair proteins in 18 benign nevi and 101 stage I to III PMs and investigated their association with tumor clinicopathologic variables and melanoma mortality. RESULTS Expression of MSH2, MLH1, and PMS2 was high in benign nevi and reduced in a subset of PMs. Conversely, MSH6 expression was absent or extremely low in benign nevi and increased in a subset of PMs. In the multivariate analysis, including sex, age, Breslow thickness, and ulceration, high MSH6 expression in PMs (ie, immunostaining in >20% of tumor cells) was significantly associated with an increased risk of melanoma mortality (relative risk, 3.76; 95% confidence interval, 1.12-12.70). CONCLUSIONS MSH6 protein expression can be a valuable marker to improve prognosis assessment in PMs.

Targeting the PI3K/AKT/mTOR pathway overcomes the stimulating effect of dabrafenib on the invasive behavior of melanoma cells with acquired resistance to the BRAF inhibitor.

BRAF inhibitors (BRAFi) have proven clinical benefits in patients with BRAF-mutant melanoma. However, acquired resistance eventually arises. The effects of BRAFi on melanoma cell proliferation and survival have been extensively studied, and several mechanisms involved in acquired resistance to the growth suppressive activity of these drugs have been identified. Much less is known about the impact of BRAFi, and in particular of dabrafenib, on the invasive potential of melanoma cells. In the present study, the BRAF-mutant human melanoma cell line A375 and its dabrafenib-resistant subline A375R were analyzed for invasive capacity, expression of vascular endothelial growth factor receptor (VEGFR)-2, and secretion of VEGF-A and matrix metalloproteinase (MMP)-9, under basal conditions or in response to dabrafenib. The consequences of inhibiting the PI3K/AKT/mTOR pathway on A375R cell responses to dabrafenib were also evaluated. We found that A375R cells were more invasive and secreted higher levels of VEGF-A and MMP-9 as compared with A375 cells. Dabrafenib reduced invasiveness, VEGFR-2 expression and VEGF-A secretion in A375 cells, whereas it increased invasiveness, VEGF-A and MMP-9 release in A375R cells. In these latter cells, the stimulating effects of dabrafenib on the invasive capacity were markedly impaired by the anti-VEGF‑A antibody bevacizumab, or by AKT1 silencing. A375R cells were not cross-resistant to the PI3K/mTOR inhibitor GSK2126458A. Moreover, this inhibitor given in combination with dabrafenib efficiently counteracted the stimulating effects of the BRAFi on invasiveness and VEGF-A and MMP-9 secretion. Our data demonstrate that melanoma cells with acquired resistance to dabrafenib possess a more invasive phenotype which is further stimulated by exposure to the drug. Substantial evidence indicates that continuing BRAFi therapy beyond progression produces a clinical benefit. Our results suggest that after the development of resistance, a regimen combining BRAFi with bevacizumab or with inhibitors of the PI3K/AKT/mTOR pathway might be more effective than BRAFi monotherapy.

Association of CTLA-4 gene variants with response to therapy and long-term survival in metastatic melanoma patients treated with ipilimumab: An Italian melanoma intergroup study

Ipilimumab (IPI) blocks CTLA-4 immune checkpoint resulting in T cell activation and enhanced antitumor immunity. IPI improves overall survival (OS) in 22% of patients with metastatic melanoma (MM). We investigated the association of CTLA-4 single nucleotide variants (SNVs) with best overall response (BOR) to IPI and OS in a cohort of 173 MM patients. Patients were genotyped for six CTLA-4 SNVs (−1661A>G, −1577G>A, −658C>T, −319C>T, +49A>G, and CT60G>A). We assessed the association between SNVs and BOR through multinomial logistic regression (MLR) and the prognostic effect of SNVs on OS through Kaplan–Meier method. Both −1577G>A and CT60G>A SNVs were found significantly associated with BOR. In particular, the proportion of responders was higher in G/G genotype while that of stable patients was higher in A/A genotype. The frequency of patients experiencing progression was similar in all genotypes. MLR evidenced a strong downward trend in the probability of responsiveness/progression, in comparison to disease stability, as a function of the allele A “dose” (0, 1, or 2) in both SNVs with reductions of about 70% (G/A vs G/G) and about 95% (A/A vs G/G). Moreover, −1577G/G and CT60G/G genotypes were associated with long-term OS, the surviving patients being at 3 years 29.8 and 30.8%, respectively, as compared to 12.9 and 14.4% of surviving patients carrying −1577G/A and CT60G/A, respectively. MM patients carrying −1577G/G or CT60G/G genotypes may benefit from IPI treatment in terms of BOR and long-term OS. These CTLA-4 SNVs may serve as potential biomarkers predictive of favorable outcome in this subset of patients.

Placenta growth factor and neuropilin-1 collaborate in promoting melanoma aggressiveness

The placenta growth factor (PlGF) is a member of the vascular endothelial growth factor (VEGF) family, which shares with VEGF-A the tyrosine kinase receptor VEGFR-1 and the co-receptor neuropilin-1 (NRP-1). In melanoma models, PlGF enhances tumour growth and neovessel formation, whereas NRP-1 promotes the metastatic process. Increased secretion of PlGF and expression of NRP-1 have also been involved in intrinsic or acquired resistance to anti‑angiogenic therapies. In this study we investigated whether PlGF and NRP-1 cooperate in promoting melanoma aggressiveness independently of VEGFR-1. For this purpose, the melanoma cell clones M14-N, expressing NRP-1 and lacking VEGFR-1, and M14-C, devoid of both receptors, were used. M14-N cells are characterized by an invasive phenotype and vasculogenic mimicry, whereas M14-C cells possess a negligible invasive capacity. The results indicated that M14-N cells secrete higher levels of PlGF than M14-C cells and that PlGF is involved in the invasion of the extracellular matrix (ECM) and vasculogenic mimicry of M14-N cells. In fact, neutralizing antibodies against PlGF reverted ECM invasion in response to PlGF and markedly reduced the formation of tubule-like structures. Moreover, M14-N cells migrated in response to PlGF and chemotaxis was specifically abrogated by anti-NRP-1 antibodies, demonstrating that PlGF directly activates NRP-1 in the absence of VEGFR-1. We also compared the levels of PlGF in the plasma of patients affected by metastatic melanoma with those of healthy donors and evaluated whether PlGF levels could be affected by a bevacizumab-containing chemotherapy regimen. Melanoma patients showed a 20-fold increase in plasma PlGF and the bevacizumab-containing regimen induced a reduction of VEGF-A and in a further increase of PlGF. In conclusion, our studies suggest that the activation of NRP-1 by PlGF directly contributes to melanoma aggressiveness and represents a potential compensatory pro-angiogenic mechanism that may contribute to the resistance to therapies targeting VEGF-A.

Baseline relative eosinophil count as a predictive biomarker for ipilimumab treatment in advanced melanoma

As diverse therapeutic options are now available for advanced melanoma patients, predictive markers that may assist treatment decision are needed. A model based on baseline serum lactate dehydrogenase (LDH), peripheral blood relative lymphocyte counts (RLC) and eosinophil counts (REC) and pattern of distant metastasis, has been recently proposed for pembrolizumab-treated patients. Here, we applied this model to advanced melanoma patients receiving chemotherapy (n = 116) or anti-CTLA-4 therapy (n = 128). Visceral involvement, LDH and RLC were associated with prognosis regardless of treatment. Instead, when compared to chemotherapy-treated patients with REC < 1.5%, those with REC ≥ 1.5% had improved overall survival when receiving anti-CTLA-4 [Hazard Ratio (HR) = 0.56 (0.4–0.93)] but not chemotherapy [HR = 1.13, (0.74–1.74)], and the treatment-by-REC interaction was significant for both overall (p = 0.04) and progression free survival (p = 0.009). These results indicate baseline REC ≥ 1.5% as a candidate predictive biomarker for benefit from anti-CTLA-4. Further studies are needed to confirm these findings in patients receiving immune-modulating agents.

Farmacogenomica e chemioterapia: attuali conoscenze

Genetic factors could alter drug metabolism and activity and could predict drug toxicity and/or efficacy. Several chemotherapy agents are administered in different schedules for the treatment of different cancer histotypes. The most used drug in the treatment of gastro-intestinal, head and neck and breast neoplasms is the 5-fluorouracil (5-FU). Capecitabine is a prodrug of 5-FU. Cisplatin based chemotherapy is administered in the treatment of lung, genitourinary tract, head and neck, occult neoplasms, mesothelioma and melanoma. Taxanes are used in lung, breast, head and neck, genitourinary tract neoplasms and sarcomas. Determination of polymorphisms in metabolizing enzymes before the administration of chemotherapy could offer new strategies for optimizing the treatment of individual patients.

Extracellular nicotinamide phosphoribosyltransferase (eNAMPT) is a novel marker for patients with BRAF-mutated metastatic melanoma

Metastatic melanoma carrying BRAF mutations represent a still unmet medical need as success of BRAF inhibitors is limited by development of resistance. Nicotinamide phosphoribosyltransferase (NAMPT) is a key enzyme in NAD biosynthesis. An extracellular form (eNAMPT) possesses cytokine-like functions and is up-regulated in inflammatory disorders, including cancer. Here we show that eNAMPT is actively released in culture supernatants of melanoma cell lines. Furthermore, cells that become resistant to BRAF inhibitors (BiR) show a significant increase of eNAMPT levels. Plasma from mice xenografted with BiR cell lines contain higher eNAMPT levels compared to tumor-free animals. Consistently, eNAMPT levels are elevated in 113 patients with BRAF-mutated metastatic melanoma compared to 50 with localized disease or to 38 healthy donors, showing a direct correlation with markers of tumor burden, such as LDH, or aggressive disease (such as PD-L1). eNAMPT concentrations decrease in response to therapy with BRAF/MEK inhibitors, but increase again at progression, as inferred from the serial analysis of 50 patients. Lastly, high eNAMPT levels correlate with a significantly shorter overall survival. Our findings suggest that eNAMPT is a novel marker of tumor burden and response to therapy in patients with metastatic melanoma carrying BRAF mutations.

Targeting the PTTG1 oncogene impairs proliferation and invasiveness of melanoma cells sensitive or with acquired resistance to the BRAF inhibitor dabrafenib

The pituitary tumor transforming gene 1 (PTTG1) is implicated in tumor growth, metastasis and drug resistance. Here, we investigated the involvement of PTTG1 in melanoma cell proliferation, invasiveness and response to the BRAF inhibitor (BRAFi) dabrafenib. We also preliminary assessed the potential value of circulating PTTG1 protein to monitor melanoma patient response to BRAFi or to dabrafenib plus trametinib. Dabrafenib-resistant cell lines (A375R and SK-Mel28R) were more invasive than their drug-sensitive counterparts (A375 and SK-Mel28), but expressed comparable PTTG1 levels. Dabrafenib abrogated PTTG1 expression and impaired invasion of the extracellular matrix (ECM) in A375 and SK-Mel28 cells. In contrast, it affected neither PTTG1 expression in A375R and SK-Mel28R cells, nor ECM invasion in the latter cells, while further stimulated A375R cell invasiveness. Assessment of proliferation and ECM invasion in control and PTTG1-silenced A375 and SK-Mel28 cells, exposed or not to dabrafenib, demonstrated that the inhibitory effects of this drug were, at least in part, dependent on its ability to down-regulate PTTG1 expression. PTTG1-silencing also impaired proliferation and invasiveness of A375R and SK-Mel28R cells, and counteracted dabrafenib-induced stimulation of ECM invasion in A375R cells. Further experiments performed in A375R cells indicated that PTTG1-silencing impaired cell invasiveness through inhibition of MMP-9 and that PTTG1 expression and ECM invasion could be also reduced by the CDK4/6 inhibitor LEE011. PTTG1 targeting might, therefore, represent a useful strategy to impair proliferation and metastasis of melanomas resistant to BRAFi. Circulating PTTG1 also appeared to deserve further investigation as biomarker to monitor patient response to targeted therapy.

Melanoma cells with acquired resistance to dabrafenib display changes in miRNA expression pattern and respond to this drug with an increase of invasiveness, which is abrogated by inhibition of NF-κB or the PI3K/mTOR signalling pathway

Melanoma cells with acquired resistance to dabrafenib display changes in miRNA expression pattern and respond to this drug with an increase of invasiveness, which is abrogated by inhibition of NFB or the PI3K/mTOR signalling pathway Simona Caporali, Ester Alvino, Adriana Amaro, Pedro Miguel Lacal, Lauretta Levati, Maria Grazia Atzori, Gian Carlo Antonini Cappellini, Federica Ruffini, Enzo Bonmassar, Ulrich Pfeffer, Stefania D’Atri