Selective Oral MEK1/2 Inhibitor Pimasertib in Metastatic Melanoma: Antitumor Activity in a Phase I, Dose-Escalation Trial

A novel, glutathione-activated prodrug of pimasertib loaded in liposomes for targeted cancer therapy

Pimasertib, a potent antiproliferative drug, has been extensively studied for treating cancers characterized by dysregulation in the ERK/MAPK signaling pathway, such as melanoma. However, its therapeutic efficacy would greatly benefit from an increased selectivity for tumour cells and a longer half-life. Such improvements may be achieved by combining the rational design of a prodrug with its encapsulation in a potential nanodelivery system. For this reason, we synthesized a glutathione (GSH)-responsive putative prodrug of pimasertib (PROPIMA), which contains a redox-sensitive disulphide linker that can be processed by GSH to activate pimasertib. The synthesis of PROPIMA and its in vitro biological activity on a human melanoma cell line as a model are described. The results showed that PROPIMA, either free or embedded in liposomes, selectively inhibits cell proliferation and cell viability, reducing by about 5-fold the levels of pERK. Additionally, PROPIMA shows stronger inhibition of the cancer cell migration than the parent drug.

Inactivation of kindlin-3 increases human melanoma aggressiveness through the collagen-activated tyrosine kinase receptor DDR1

The role of the focal adhesion protein kindlin-3 as a tumor suppressor and its interaction mechanisms with extracellular matrix constitute a major field of investigation to better decipher tumor progression. Besides the well-described role of kindlin-3 in integrin activation, evidence regarding modulatory functions between melanoma cells and tumor microenvironment are lacking and data are needed to understand mechanisms driven by kindlin-3 inactivation. Here, we show that kindlin-3 inactivation through knockdown or somatic mutations increases BRAFV600mut melanoma cells oncogenic properties via collagen-related signaling by decreasing cell adhesion and enhancing proliferation and migration in vitro, and by promoting tumor growth in mice. Mechanistic analysis reveals that kindlin-3 interacts with the collagen-activated tyrosine kinase receptor DDR1 (Discoidin domain receptor 1) modulating its expression and its interaction with β1-integrin. Kindlin-3 knockdown or mutational inactivation disrupt DDR1/β1-integrin complex in vitro and in vivo and its loss improves the anti-proliferative effect of DDR1 inhibition. In agreement, kindlin-3 downregulation is associated with DDR1 over-expression in situ and linked to worse melanoma prognosis. Our study reveals a unique mechanism of action of kindlin-3 in the regulation of tumorigenesis mediated by the collagen-activated tyrosine kinase receptor DDR1 thus paving the way for innovative therapeutic targeting approaches in melanoma.

Targeted therapeutic strategies for melanoma

ABSTRACT

Melanoma accounts for a small proportion of skin cancers diagnosed each year, but it has a high degree of malignancy and rapid progression, resulting in a short survival period for patients. The incidence of melanoma continues to rise, and now melanoma accounts for 1.7% of cancer diagnoses worldwide and is the fifth most common cancer in the United States. With the development of high-throughput sequencing technologies, the understanding of the pathophysiology of melanoma had also been improved. The most common activating mutations in melanoma cells are BRAF , NRAS , and KIT mutations, which disrupt cell signaling pathways related to tumor proliferation. The progress has led to the emergence of molecularly targeted drugs, which extends the survival of patients with advanced melanoma. A large number of clinical trials have been conducted to confirm that targeted therapy for patients with advanced melanoma can improve progression-free survival and overall survival, and for stage III patients after radical tumor resection targeted therapy can reduce the recurrence of melanoma. Patients who were originally stage III or IV inoperable have the opportunity to achieve tumor radical resection after targeted therapy. This article reviewed the clinical trial data and summarized the clinical benefits and limitations of these therapies.

Role of protein phosphorylation in cell signaling, disease, and the intervention therapy

Protein phosphorylation is an important post-transcriptional modification involving an extremely wide range of intracellular signaling transduction pathways, making it an important therapeutic target for disease intervention. At present, numerous drugs targeting protein phosphorylation have been developed for the treatment of various diseases including malignant tumors, neurological diseases, infectious diseases, and immune diseases. In this review article, we analyzed 303 small-molecule protein phosphorylation kinase inhibitors (PKIs) registered and participated in clinical research obtained in a database named Protein Kinase Inhibitor Database (PKIDB), including 68 drugs approved by the Food and Drug Administration of the United States. Based on previous classifications of kinases, we divided these human protein phosphorylation kinases into eight groups and nearly 50 families, and delineated their main regulatory pathways, upstream and downstream targets. These groups include: protein kinase A, G, and C (AGC) and receptor guanylate cyclase (RGC) group, calmodulin-dependent protein kinase (CaMK) group, CMGC [Cyclin-dependent kinases (CDKs), Mitogen-activated protein kinases (MAPKs), Glycogen synthase kinases (GSKs), and Cdc2-like kinases (CLKs)] group, sterile (STE)-MAPKs group, tyrosine kinases (TK) group, tyrosine kinase-like (TKL) group, atypical group, and other groups. Different groups and families of inhibitors stimulate or inhibit others, forming an intricate molecular signaling regulatory network. This review takes newly developed new PKIs as breakthrough point, aiming to clarify the regulatory network and relationship of each pathway, as well as their roles in disease intervention, and provide a direction for future drug development.

Multi-Omics Immune Interaction Networks in Lung Cancer Tumorigenesis, Proliferation, and Survival

There are currently no effective biomarkers for prognosis and optimal treatment selection to improve non-small cell lung cancer (NSCLC) survival outcomes. This study further validated a seven-gene panel for diagnosis and prognosis of NSCLC using RNA sequencing and proteomic profiles of patient tumors. Within the seven-gene panel, ZNF71 expression combined with dendritic cell activities defined NSCLC patient subgroups (n = 966) with distinct survival outcomes (p = 0.04, Kaplan-Meier analysis). ZNF71 expression was significantly associated with the activities of natural killer cells (p = 0.014) and natural killer T cells (p = 0.003) in NSCLC patient tumors (n = 1016) using Chi-squared tests. Overexpression of ZNF71 resulted in decreased expression of multiple components of the intracellular intrinsic and innate immune systems, including dsRNA and dsDNA sensors. Multi-omics networks of ZNF71 and the intracellular intrinsic and innate immune systems were computed as relevant to NSCLC tumorigenesis, proliferation, and survival using patient clinical information and in-vitro CRISPR-Cas9/RNAi screening data. From these networks, pan-sensitive and pan-resistant genes to 21 NCCN-recommended drugs for treating NSCLC were selected. Based on the gene associations with patient survival and in-vitro CRISPR-Cas9, RNAi, and drug screening data, MEK1/2 inhibitors PD-198306 and U-0126, VEGFR inhibitor ZM-306416, and IGF-1R inhibitor PQ-401 were discovered as potential targeted therapy that may also induce an immune response for treating NSCLC.

Identification of New Vulnerabilities in Conjunctival Melanoma Using Image-Based High Content Drug Screening

Recent evidence suggests that numerous similarities exist between the genomic landscapes of both conjunctival and cutaneous melanoma. Since alterations of several components of the MAP kinases, PI3K/mTOR, and cell cycle pathways have been reported in conjunctival melanoma, we decided to assess the sensitivity of conjunctival melanoma to targeted inhibition mostly of kinase inhibitors. A high content drug screening assay based on automated fluorescence microscopy was performed in three conjunctival melanoma cell lines with different genomic backgrounds with 489 kinase inhibitors and 53 other inhibitors. IC50 and apoptosis induction were respectively assessed for 53 and 48 compounds. The genomic background influenced the response to MAK and PI3K/mTOR inhibition, more specifically cell lines with BRAF V600E mutations were more sensitive to BRAF/MEK inhibition, while CRMM2 bearing the NRASQ61L mutation was more sensitive to PI3k/mTOR inhibition. All cell lines demonstrated sensitivity to cell cycle inhibition, being more pronounced in CRMM2, especially with polo-like inhibitors. Our data also revealed new vulnerabilities to Hsp90 and Src inhibition. This study demonstrates that the genomic background partially influences the response to targeted therapy and uncovers a large panel of potential vulnerabilities in conjunctival melanoma that may expand available options for the management of this tumor.

Pharmacogenomics in solid cancers and hematologic malignancies: Improving personalized drug prescription

The discovery of molecular alterations involved in oncogenesis is evolving rapidly and has led to the development of new innovative targeted therapies in oncology. High-throughput sequencing techniques help to identify genomic targets and to provide predictive molecular biomarkers of response to guide alternative therapeutic strategies. Besides the emergence of these theranostic markers for the new targeted treatments, pharmacogenetic markers (corresponding to genetic variants existing in the constitutional DNA, i.e., the host genome) can help to optimize the use of chemotherapy. In this review, we present the current clinical applications of constitutional PG and the recent concepts and advances in pharmacogenomics, a rapidly evolving field that focuses on various molecular alterations identified on constitutional or somatic (tumor) genome.

Oncogenic KRAS blockade therapy: renewed enthusiasm and persistent challenges

Across a broad range of human cancers, gain-of-function mutations in RAS genes (HRAS, NRAS, and KRAS) lead to constitutive activity of oncoproteins responsible for tumorigenesis and cancer progression. The targeting of RAS with drugs is challenging because RAS lacks classic and tractable drug binding sites. Over the past 30 years, this perception has led to the pursuit of indirect routes for targeting RAS expression, processing, upstream regulators, or downstream effectors. After the discovery that the KRAS-G12C variant contains a druggable pocket below the switch-II loop region, it has become possible to design irreversible covalent inhibitors for the variant with improved potency, selectivity and bioavailability. Two such inhibitors, sotorasib (AMG 510) and adagrasib (MRTX849), were recently evaluated in phase I-III trials for the treatment of non-small cell lung cancer with KRAS-G12C mutations, heralding a new era of precision oncology. In this review, we outline the mutations and functions of KRAS in human tumors and then analyze indirect and direct approaches to shut down the oncogenic KRAS network. Specifically, we discuss the mechanistic principles, clinical features, and strategies for overcoming primary or secondary resistance to KRAS-G12C blockade.

Molecular Markers and Targets in Melanoma

Melanoma develops as a result of several genetic alterations, with UV radiation often acting as a mutagenic risk factor. Deep knowledge of the molecular signaling pathways of different types of melanoma allows better characterization and provides tools for the development of therapies based on the intervention of signals promoted by these cascades. The latest World Health Organization classification acknowledged the specific genetic drivers leading to melanoma and classifies melanocytic lesions into nine distinct categories according to the associate cumulative sun damage (CSD), which correlates with the molecular alterations of tumors. The largest groups are melanomas associated with low-CSD or superficial spreading melanomas, characterized by frequent presentation of the BRAFV600 mutation. High-CSD melanomas include lentigo maligna type and desmoplastic melanomas, which often have a high mutation burden and can harbor NRAS, BRAFnon-V600E, or NF1 mutations. Non-CSD-associated melanomas encompass acral and mucosal melanomas that usually do not show BRAF, NRAS, or NF1 mutations (triple wild-type), but in a subset may have KIT or SF3B1 mutations. To improve survival, these driver alterations can be treated with targeted therapy achieving significant antitumor activity. In recent years, relevant improvement in the prognosis and survival of patients with melanoma has been achieved, since the introduction of BRAF/MEK tyrosine kinase inhibitors and immune checkpoint inhibitors. In this review, we describe the current knowledge of molecular pathways and discuss current and potential therapeutic targets in melanoma, focusing on their clinical relevance of development.

Selective Oral MEK1/2 Inhibitor Pimasertib: A Phase I Trial in Patients with Advanced Solid Tumors

BACKGROUND

The Ras/Raf/mitogen-activated protein kinase kinase/extracellular signal-regulated kinase (Ras/Raf/MEK/ERK) signaling cascade is frequently constitutively activated in human cancers. Pimasertib is a selective and potent adenosine triphosphate non-competitive MEK1/2 inhibitor.

OBJECTIVE

Our objectives were to describe the results of a phase I, first-in-human, dose-escalation trial of pimasertib that investigated the maximum tolerated dose, recommended phase II dose, and safety, as well as other endpoints.

PATIENTS AND METHODS

Four dosing schedules of pimasertib (once daily [qd], 5 days on, 2 days off; qd, 15 days on, 6 days off; continuous qd; continuous twice daily [bid]) were evaluated in patients with advanced solid tumors. Each treatment cycle lasted 21 days. The primary objective was to determine the maximum tolerated dose based on dose-limiting toxicities (DLTs) evaluated during cycle 1, and the recommended phase II dose (RP2D). Secondary objectives included safety, pharmacokinetics, pharmacodynamics, and antitumor activity.

RESULTS

Overall, 180 patients received pimasertib (dose range 1-255 mg/day). DLTs were mainly observed at doses ≥ 120 mg/day and included skin rash/acneiform dermatitis and ocular events, such as serous retinal detachment. The most common drug-related adverse events were consistent with class effects, including diarrhea, skin disorders, ocular disorders, asthenia/fatigue, and peripheral edema. The median time to maximum pimasertib concentration was 1.5 h across dosing schedules, and the apparent terminal half-life was 5 h across qd dosing schedules. Pimasertib decreased ERK phosphorylation within 2 h of administration, which was maintained for up to 8 h at higher doses and prolonged with bid dosing.

CONCLUSIONS

Based on the safety profile and efficacy signals, a continuous bid regimen was the preferred dosing schedule and the RP2D was defined as 60 mg bid.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT00982865.