Targeting of PDGF-C/NRP-1 autocrine loop as a new strategy for counteracting the invasiveness of melanoma resistant to braf inhibitors

: Melanoma resistance to BRAF inhibitors (BRAFi) is often accompanied by a switch from a proliferative to an invasive phenotype. Therefore, the identification of signaling molecules involved in the development of metastatic properties by resistant melanoma cells is of primary importance. We have previously demonstrated that activation of neuropilin-1 (NRP-1) by platelet-derived growth factor (PDGF)-C confers melanoma cells with an invasive behavior similar to that of BRAFi resistant tumors. Aims of the present study were to evaluate the role of PDGF-C/NRP-1 autocrine loop in the acquisition of an invasive and BRAFi-resistant phenotype by melanoma cells and the effect of its inhibition on drug resistance and extracellular matrix (ECM) invasion. Furthermore, we investigated whether PDGF-C serum levels were differentially modulated by drug treatment in metastatic melanoma patients responsive or refractory to BRAFi as single agents or in combination with MEK inhibitors (MEKi). The results indicated that human melanoma cells resistant to BRAFi express higher levels of PDGF-C and NRP-1 as compared to their susceptible counterparts. Overexpression occurs early during development of drug resistance and contributes to the invasive properties of resistant cells. Accordingly, silencing of NRP-1 or PDGF-C reduces tumor cell invasiveness. Analysis of PDGF-C in the serum collected from patients treated with BRAFi or BRAFi+MEKi, showed that in responders PDGF-C levels decrease after treatment and raise again at tumor progression. Conversely, in non-responders treatment does not affect PDGF-C serum levels. Thus, blockade of NRP-1 activation by PDGF-C might represent a new therapeutic approach to counteract the invasiveness of BRAFi-resistant melanoma

Dabrafenib plus trametinib is effective in the treatment of BRAF V600-mutated metastatic melanoma patients:analysis of patients from the dabrafenib plus trametinib Named Patient Program (DESCRIBE II)

In clinical trials, dabrafenib plus trametinib improved overall survival (OS) compared with single-agent BRAF inhibitors (BRAFi) in patients with BRAF V600-mutant unresectable or metastatic melanoma. We investigated dabrafenib plus trametinib therapy in a compassionate-use setting [Named Patient Program (NPP); DESCRIBE II]. A retrospective chart review of patients with BRAF V600-mutated unresectable stage III/IV melanoma receiving dabrafenib plus trametinib as compassionate use was conducted. Treatment patterns and duration, clinical outcomes, and tolerability were evaluated. Of 271 patients, 92.6% had stage IV melanoma, including 36.5% with brain metastases. Overall, 162 patients (59.8%) were BRAFi naive and 171 (63.1%) received first-line dabrafenib plus trametinib. Among BRAFi-naive patients, the overall response rate (ORR) was 67.3%, median OS (mOS) was 20.0 months, and median progression-free survival (mPFS) was 7.5 months. In BRAFi-naive patients with known brain metastases (n = 62), ORR was 61.3%, mOS was 15.5 months, and mPFS was 6.2 months. Eighty-four patients received BRAFi monotherapy for >30 days and switched to dabrafenib plus trametinib prior to progression. Of these 84 patients, 63 had known disease status at the time of switch, and 22 improved with the combination therapy. No new safety signals were identified, and dabrafenib plus trametinib was well tolerated. Dabrafenib plus trametinib showed substantial clinical activity in NPP patients with BRAF V600-mutated unresectable or metastatic melanoma. Analysis of treatment patterns demonstrated the effectiveness of the combination in patients with brain metastases and across lines of therapy with a well tolerated and manageable safety profile

Predictors of mood disorders in cancer patients' caregivers

Patients' care has been associated with a high burden of psychological symptoms in caregivers. This study identifies characteristics associated with mood disorders in caregivers of cancer patients. One hundred fifty-two caregivers, aged 24-78 years (average age 51; 60 % females), of cancer patients completed Family Strain Questionnaire (FSQ), Hospital Anxiety and Depression Scale (HADS), Impact of Event Scale (IES), and Coping Orientations to the Problems Experienced. We combined this information with patient chart abstraction data. Sixty-three percent of females and 38 % of males were scored as positive when screened for mood disorders, as measured by HADS (total score a parts per thousand yen16), and 17 and 5 % for emotional distress as measured by IES (total score a parts per thousand yen50). High scores in FSQ-satisfaction with family relationships and FSQ-need for more information about cancer, and low scores in FSQ-thoughts about death are reported. FSQ-emotional burden and FSQ-problems in social involvement are the areas more compromised in females, compared to males. Females, compared to males, use emotional-oriented coping strategies more frequently. Factors independently associated with mood disorders included emotional burden, problems in social involvement, and non-attendance of meeting places; help and assistance from public local services (for patients) decreased the risk of mood disorders in caregivers. Prevalence of mood disorders is high in cancer patients' caregivers. These results highlight the need to develop family intervention strategies to minimize the impact of patient's care on caregivers' mental health

[Pharmacogenomics and chemotherapy]

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

Treatment-related side effects and quality of life in cancer patients

Cancer leads to a complicated pattern of change in quality of life (QoL). The aims of this study were to assess the impact of treatment-related side effects on QoL in cancer patients and to explore which other factors, and to what extent, contribute to explain low QoL scores. One hundred twenty-three cancer patients receiving chemotherapy completed the self-administered questionnaires (Medical Outcomes Short-Form-36 (SF-36) and 12-item General Health Questionnaire). Multiple regression analyses were conducted with the SF-36 physical component summary (PCS) and SF-36 mental component summary (MCS) scores as the dependent variables and demographic and clinical factors as independent variables. Seventy-two percent of patients experienced treatment-related side effects, and 32% resulted positive for psychiatric diseases. Two multivariate analyses showed that worse PCS scores, like worse MCS scores, were significantly and independently predicted by treatment-related side effects (odds ratio (OR) = 5.00, 95%CI 1.29-19.45; OR = 8.08, 95%CI 2.03-32.22, respectively) and changes in health over the last 12 months (OR =2.34, 95%CI 1.47-3.76; OR = 3.21, 95%CI 1.90-5.41, respectively), after adjustment for age, gender, years of school, time from cancer diagnosis, and psychiatric disease. Given the new emphasis on QoL, we suggest that physicians have a responsibility to openly discuss therapy efficacy, prognosis as well as the potential for adverse events with their patients. Changes in health, as perceived by patient, should also be monitored at follow-up

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-VEGFA 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

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