Systemic Chemotherapy

Adipocytes Promote B16BL6 Melanoma Cell Invasion and the Epithelial-to-Mesenchymal Transition

Metastatic melanoma is one of the most deadly and evasive types of cancer. On average, cancer patients with metastatic melanoma survive only 6-9 months after diagnosis. Epidemiological and animal studies suggest that obesity increases the metastatic ability of malignant melanoma, though the mechanism is not known. In the present studies, we assessed the ability of 3T3L1 adipocytes to modulate B16BL6 melanoma cell invasion and the Epithelial-to-Mesenchymal Transition (EMT). For this purpose, we induced the differentiation of 3T3L1 fibroblasts to adipocytes. Then, we collected the cell culture media from both fibroblasts and adipocytes and determined their effect on the invasive ability and EMT gene expression of B16BL6 melanoma cells. Results show that adipocyte media increased that ability of B16BL6 cells to invade. The higher invasive ability of B16BL6 melanoma cells was associated with increased expression of EMT genes such as Snai1, MMP9, Twist, and Vimentin. Additionally, the expression of the cell-to-cell adhesion protein E-cadherin and the metastasis suppressor gene Kiss1 were down-regulated in these B16BL6 cells. Also, adipocytes had high levels of the pro-inflammatory cytokine Interleukin 6 (IL-6). Treatment of B16BL6 cells with IL-6 elicited similar effects as the adipocyte media; IL-6 promoted the invasive ability of B16BL6 melanoma cells, increased the expression of Snai1, and decreased Kiss1 expression. IL-6 neutralization, however, did not have a visible effect on adipocyte media-induced invasion and snai1 staining. In summary, adipocytes may increase the invasive ability of B16BL6 melanoma cells by promoting EMT and decreasing the expression of genes such as E-cadherin and Kiss1.

Ob/ob serum promotes a mesenchymal cell phenotype in B16BL6 melanoma cells

In 2009, malignant melanoma was responsible for approximately 9,000 deaths in the US. These deaths are often associated with aggressive metastasis to secondary sites such as the lungs. Epidemiological and animal studies suggest that obesity is a risk factor for melanoma. Others have shown that B16BL6 melanoma cells metastasize more aggressively in obese ob/ob than in lean mice. However, the mechanism by which obesity promotes B16BL6 melanoma metastasis in ob/ob mice has not been identified. In the present study, we used serum obtained from control and ob/ob leptin-deficient obese mice to determine if obese serum increases the aggressive phenotype of melanoma cells. Results showed that ob/ob serum has higher levels of resistin, insulin, tPAI1, IL-6, TNF-α, and MCP-1 compared to control serum. We showed that ob/ob serum increases the invasive ability of B16BL6 melanomas. To further determine the mechanism by which ob/ob serum increases the invasive ability of melanomas, we determined the effect of ob/ob and control serum on genes associated with the epithelial-to-mesenchymal transition (EMT). Cancer cells with a mesenchymal phenotype have a higher metastatic ability. Snai1 and Twist are genes that are strongly associated with EMT and metastasis of melanomas. Our results showed that ob/ob serum increases the expression of Snai1 and Twist. Moreover, ob/ob serum increased matrix metalloproteast 9 (MMP9) activity and decreased the expression of E-cadherin and the metastasis suppressor gene Kiss1. In summary, results suggest that obesity may increase the metastatic ability of melanoma by promoting a mesenchymal cell phenotype.

Phase II Trial of Karenitecin in Patients with Malignant Melanoma: Clinical and Translational Study

PURPOSE

A phase II trial of the novel camptothecin karenitecin (BNP1350) was conducted to determine its efficacy and tolerability in patients with metastatic melanoma. Patients were biopsied to determine topoisomerase expression at baseline and response to therapy.

PATIENTS AND METHODS

Eligible patients had metastatic melanoma with up to three prior chemotherapy and/or any number of immunotherapy regimens. Treatment consisted of an i.v. infusion of 1 mg/m(2) karenitecin daily for 5 days with cycles repeated every 3 weeks. Fine-needle aspiration biopsies were done before treatment and on day 3 to determine topoisomerase expression from patients' tumors.

RESULTS

Forty-three patients were evaluable for response and toxicity. Most patients (72%) had stage M1C disease and were previously exposed to chemotherapy (56%). The investigational agent was well tolerated with limited gastrointestinal side effects or fatigue. The major toxicity seen was reversible noncumulative myelosuppression. One patient had a complete response after 11 months of therapy. No partial responses were seen, but 33% of the patients had disease stabilization lasting > or =3 months. Topoisomerase I, IIalpha, and IIbeta expression and localization were determined in a subset of patients. Topoisomerase I expression was highest, followed by topoisomerase IIbeta and topoisomerase IIalpha.

CONCLUSION

Karenitecin was a well-tolerated investigational agent in this phase II study; side effects were generally mild and mostly hematologic. Karenitecin has significant activity in metastatic melanoma. Melanoma metastases express high levels of topoisomerase I. We did not observe any compensatory increase in topoisomerase II upon treatment with karenitecin.

Normal values of serum S-100B predict prolonged survival for stage IV melanoma patients

The value of normal S-100B levels to predict survival was evaluated in 145 patients with stage IV melanoma. Treatment consisted of temozolomide given alone or was followed by combined cytokine immunotherapy, given every three to four weeks, with an evaluation of response following two treatment-cycles. S-100B values were measured prior to and following each cycle of systemic therapy and regularly thereafter. Patients with normal initial S-100B values (n=32) had higher response rates and fewer and more favourable metastatic sites with better overall survival rates than patients with elevated S-100B levels (median 14.0 versus 6.6 months). Normal S-100B values increased in nearly all patients (28/31) after a median of 7.9 months. In addition, patients with rapid normalisation of their serum level (n=12) following systemic treatment experienced prolonged survival. However, upon multivariable analysis S-100B prior to treatment lost its independence as a prognostic factor, whereas lactate dehydrogenase (LDH) remained. When measured after treatment, both markers had independent value.

Systemic chemotherapy in the treatment of malignant melanoma

Different postsurgical therapies are used for the treatment of metastatic melanoma. This article reviews the use of chemotherapeutic agents in the treatment of patients with metastatic malignant melanoma. A variety of single chemotherapy agents have been evaluated, although the most widely used chemotherapeutic in the treatment of metastatic melanoma is dacarbazine. In order to improve the rate and duration of responses, combination chemotherapy was developed. The most common combined chemotherapy regimens used as standard for the treatment of metastatic melanoma are Dartmouth regimen, CVD (cisplatin + vinblastine + dacarbazine) and BOLD (bleomycin + vincristine + lomustine + dacarbazine). However, Phase III trials have failed to demonstrate a significant benefit in survival in patients treated with polychemotherapy compared to those treated with dacarbazine alone. The use of classical systemic chemotherapy still has a role in the treatment of patients with metastatic melanoma. Immunotherapy and biochemotherapy have no additional advantage over chemotherapy.

Controversies in acral lentiginous melanoma

BACKGROUND

Acral lentiginous melanoma (ALM) is a subtype of melanoma initially described only two and half decades ago, but well-recognized by dermatologists today. However, several areas of controversy surround this entity.

OBJECTIVE

The primary aims of this article are to review the literature, highlight recent advances, and review some of the ongoing controversies in ALM.

METHODS

A review of the English language literature was performed.

RESULTS

Controversy continues to surround ALM, particularly in regard to diagnostic histologic and clinical criteria. This leads to difficulties when reviewing studies that evaluate the epidemiology, etiology, and prognosis of ALM.

CONCLUSION

Progress in understanding ALM requires the development of standardized diagnostic criteria.