Targeted therapy in melanoma

Cell Death Pathways in Mutant Rhodopsin Rat Models Identifies Genotype-Specific Targets Controlling Retinal Degeneration

Retinitis pigmentosa (RP) is a group of inherited neurological disorders characterized by rod photoreceptor cell death, followed by secondary cone cell death leading to progressive blindness. Currently, there are no viable treatment options for RP. Due to incomplete knowledge of the molecular signaling pathways associated with RP pathogenesis, designing therapeutic strategies remains a challenge. In particular, preventing secondary cone photoreceptor cell loss is a key goal in designing potential therapies. In this study, we identified the main drivers of rod cell death and secondary cone loss in the transgenic S334ter rhodopsin rat model, tested the efficacy of specific cell death inhibitors on retinal function, and compared the effect of combining drugs to target multiple pathways in the S334ter and P23H rhodopsin rat models. The primary driver of early rod cell death in the S334ter model was a caspase-dependent process, whereas cone cell death occurred though RIP3-dependent necroptosis. In comparison, rod cell death in the P23H model was via necroptotic signaling, whereas cone cell loss occurred through inflammasome activation. Combination therapy of four drugs worked better than the individual drugs in the P23H model but not in the S334ter model. These differences imply that treatment modalities need to be tailored for each genotype. Taken together, our data demonstrate that rationally designed genotype-specific drug combinations will be an important requisite to effectively target primary rod cell loss and more importantly secondary cone survival.

Transcriptional control mechanisms associated with the nucleotide receptor P2X7, a critical regulator of immunologic, osteogenic, and neurologic functions

The nucleotide receptor P2X(7) is an attractive therapeutic target and potential biomarker for multiple inflammatory and neurologic disorders, and it is expressed in several immune, osteogenic, and neurologic cell types. Aside from its role in the nervous system, it is activated by ATP released at sites of tissue damage, inflammation, and infection. Ligand binding to P2X(7) stimulates many cell responses, including calcium fluxes, MAPK activation, inflammatory mediator release, and apoptosis. Much work has centered on P2X(7) action in cell death and mediator processing (e.g., pro-interleukin-1 cleavage by the inflammasome), but the contribution of P2X(7) to transcriptional regulation is less well defined. This review will focus on the growing evidence for the importance of nucleotide-mediated gene expression, highlight several animal models, human genetic, and clinical studies that support P2X(7) as a therapeutic target, and discuss the latest developments in anti-P2X(7) clinical trials.

Thoracic metastasectomy for adoptive immunotherapy of melanoma: a single-institution experience

OBJECTIVES

Although refractory to chemotherapy, metastatic melanoma may respond to adoptive immunotherapy. As novel treatments evolve, surgeons may be asked to perform metastasectomy not only for palliation or potential cure but also for isolation of tumor-infiltrating lymphocytes. This study was undertaken to examine outcomes of patients with melanoma undergoing thoracic metastasectomy in preparation for investigational immunotherapy.

METHODS

A retrospective review identified 107 consecutive patients who underwent 116 thoracic metastasectomy procedures from April 1998 to July 2009. Indications for surgical intervention included procurement of tumor-infiltrating lymphocytes, rendering of patients to no evaluable disease status, palliation, and diagnosis. Response Evaluation Criteria in Solid Tumors criteria were used to assess tumor response.

RESULTS

Thoracotomy, lobectomy, and video-assisted thoracoscopic surgery with nonanatomic resection were the most common procedures. Major complications included 1 death and 1 coagulopathy-induced hemothorax. Seventeen patients were rendered to no evaluable disease status. Virtually all patients with residual disease had tumor specimens cultured for tumor-infiltrating lymphocytes; approximately 70% of tumor-infiltrating lymphocyte cultures exhibited antitumor reactivity. Of the 91 patients with residual or recurrent disease, 24 (26%) underwent adoptive cell transfer of tumor-infiltrating lymphocytes, of whom 7 exhibited objective responses (29% response rate and 8% based on intent to treat). Rapid disease progression precluded tumor-infiltrating lymphocyte therapy in most cases. Actuarial 1- and 5-year survival rates for patients rendered to no evaluable disease status or receiving or not receiving tumor-infiltrating lymphocytes were 93% and 76%, 64% and 33%, and 43% and 0%, respectively.

CONCLUSIONS

Relatively few patients currently having thoracic metastasectomy undergo adoptive cell transfer. Continued refinement of tumor-infiltrating lymphocyte expansion protocols and improved patient selection might increase the number of patients with melanoma benefiting from these interventions.

Current research and development of chemotherapeutic agents for melanoma

Cutaneous malignant melanoma is the most lethal form of skin cancer and an increasingly common disease worldwide. It remains one of the most treatment-refractory malignancies. The current treatment options for patients with metastatic melanoma are limited and in most cases non-curative. This review focuses on conventional chemotherapeutic drugs for melanoma treatment, by a single or combinational agent approach, but also summarizes some potential novel phytoagents discovered from dietary vegetables or traditional herbal medicines as alternative options or future medicine for melanoma prevention. We explore the mode of actions of these natural phytoagents against metastatic melanoma.