A Phase I Study of Dasatinib with Concurrent Chemoradiation for Stage III Non-Small Cell Lung Cancer

YES1: a novel therapeutic target and biomarker in cancer

YES1 is a non-receptor tyrosine kinase that belongs to the SRC family of kinases (SFKs) and controls multiple cancer signaling pathways. YES1 is amplified and overexpressed in many tumor types, where it promotes cell proliferation, survival and invasiveness. Therefore, YES1 has been proposed as an emerging target in solid tumors. In addition, studies have shown that YES1 is a prognostic biomarker and a predictor of dasatinib activity. Several SFKs-targeting drugs have been developed and some of them have reached clinical trials. However, these drugs have encountered challenges to their utilization in the clinical practice in unselected patients due to toxicity and lack of efficacy. In the case of YES1, novel specific inhibitors have been developed and tested in preclinical models, with impressive antitumor effects. In this review, we summarize the structure and activation of YES1 and describe its role in cancer as a target and prognostic and companion biomarker. We also address the efficacy of SFKs inhibitors that are currently in clinical trials, highlighting the main hindrances for their clinical use. Current available information strongly suggests that inhibiting YES1 in tumors with high expression of this protein is a promising strategy against cancer.

Altering DNA Repair to Improve Radiation Therapy: Specific and Multiple Pathway Targeting

Radiation therapy (RT) is widely used in cancer care strategies. Its effectiveness relies mainly on its ability to cause lethal damage to the DNA of cancer cells. However, some cancers have shown to be particularly radioresistant partly because of efficient and redundant DNA repair capacities. Therefore, RT efficacy might be enhanced by using drugs that can disrupt cancer cells' DNA repair machinery. Here we review the recent advances in the development of novel inhibitors of DNA repair pathways in combination with RT. A large number of these compounds are the subject of preclinical/clinical studies and target key enzymes involved in one or more DNA repair pathways. A totally different strategy consists of mimicking DNA double-strand breaks via small interfering DNA (siDNA) to bait the whole DNA repair machinery, leading to its global inhibition.

Treatment-Related Noncontiguous Radiologic Changes in Children With Diffuse Intrinsic Pontine Glioma Treated With Expanded Irradiation Fields and Antiangiogenic Therapy

PURPOSE

We previously reported the cases of 3 children with diffuse intrinsic pontine glioma (DIPG) in whom noncontiguous treatment-related abnormalities (NCTRAs) developed in the brain after expanded-field radiation therapy (RT). To investigate the occurrence and putative mechanism of NCTRAs, we reviewed brain magnetic resonance imaging studies of patients with DIPG treated in 2 consecutive phase I clinical trials (trials 1 and 2).

METHODS AND MATERIALS

The 55 children included in these trials received small-molecule inhibitors: vandetanib in trial 1 (n=32; mean age 6.4 years) and vandetanib and dasatinib in trial 2 (n=23; mean age 5.8 years). The patients also received conformal 3-dimensional RT (cumulative dose 54 Gy). For patients enrolled in trial 1, the clinical target volume (CTV) was expanded by 1 cm from the gross tumor volume. In trial 2, the expansion to form the CTV was 2 to 3 cm. A review of imaging studies was performed from the initial diagnosis through the end of progression-free survival. The imaging findings were grouped into 5 categories according to the presence, absence, location, extent, and putative mechanism of NCTRAs. Statistical analysis was performed to evaluate the association between covariates and NCTRA, cohort characterization, and survival comparisons.

RESULTS

Overall survival was similar in both studies (P=.74). NCTRAs developed in 9 patients (39%) treated in trial 2 but in none treated in trial 1. The NCTRAs included T2-weighted hyperintensities with (n=3; radiation necrosis) or without (n=5) contrast uptake, supratentorial leukoencephalopathy (n=2), and ischemic stroke (n=1). All NCTRAs, except for 1, occurred within the CTV. Compared with nonaffected patients, patients with a NCTRA were younger (P=.003) and had had larger relative brain volumes exposed to doses >20 Gy.

CONCLUSIONS

The imaging features of NCTRAs suggest that their development is secondary to synergistic steno-occlusive vascular effects induced by the combination of RT, an expanded CTV, potent antiangiogenic therapy, young age, and, in 1 case, a genetic predisposition.

Dasatinib promotes paclitaxel-induced necroptosis in lung adenocarcinoma with phosphorylated caspase-8 by c-Src

Cisplatin and paclitaxel are considered to be the backbone of chemotherapy in lung adenocarcinoma. These agents show pleiotropic effects on cell death. However, the precise mechanisms remain unclear. The present study reported that phosphorylated caspase-8 at tyrosine 380 (p-Casp8) was characterized as a biomarker of chemoresistance to TP regimen (cisplatin and paclitaxel) in patients with resectable lung adenocarcinoma with significantly poorer 5-year disease-free survival (DFS) and overall survival (OS). Cisplatin killed lung adenocarcinoma cells regardless of c-Src-induced caspase-8 phosphorylation at tyrosine 380. Subsequently, we identified a novel mechanism by which paclitaxel induced necroptosis in lung adenocarcinoma cells that was dependent upon p-Casp8, receptor-interacting protein kinase 1 (RIPK1), and RIPK3. Moreover, dasatinib, a c-Src inhibitor, dephosphorylated caspase-8 to facilitate necroptosis, rather than apoptosis, in paclitaxel-treated p-Casp8-expressing lung adenocarcinoma cells. The data from our study revealed previously unrecognized roles of p-Casp8 as a positive effector in the initiation of necroptosis and as a negative effector in the repression of the interaction between RIPK1 and RIPK3. Moreover, these outcomes supported the need for further clinical studies with the goal of evaluating the efficacy of dasatinib plus paclitaxel in the treatment of lung adenocarcinoma.

Discoidin Domain Receptors: Potential Actors and Targets in Cancer

The extracellular matrix critically controls cancer cell behavior by inducing several signaling pathways through cell membrane receptors. Besides conferring structural properties to tissues around the tumor, the extracellular matrix is able to regulate cell proliferation, survival, migration, and invasion. Among these receptors, the integrins family constitutes a major class of receptors that mediate cell interactions with extracellular matrix components. Twenty years ago, a new class of extracellular matrix receptors has been discovered. These tyrosine kinase receptors are the two discoidin domain receptors DDR1 and DDR2. DDR1 was first identified in the Dictyostelium discoideum and was shown to mediate cell aggregation. DDR2 shares highly conserved sequences with DDR1. Both receptors are activated upon binding to collagen, one of the most abundant proteins in extracellular matrix. While DDR2 can only be activated by fibrillar collagen, particularly types I and III, DDR1 is mostly activated by type I and IV collagens. In contrast with classical growth factor tyrosine kinase receptors which display a rapid and transient activation, DDR1 and DDR2 are unique in that they exhibit delayed and sustained receptor phosphorylation upon binding to collagen. Recent studies have reported differential expression and mutations of DDR1 and DDR2 in several cancer types and indicate clearly that these receptors have to be taken into account as new players in the different aspects of tumor progression, from non-malignant to highly malignant and invasive stages. This review will discuss the current knowledge on the role of DDR1 and DDR2 in malignant transformation, cell proliferation, epithelial to mesenchymal transition, migratory, and invasive processes, and finally the modulation of the response to chemotherapy. These new insights suggest that DDR1 and DDR2 are new potential targets in cancer therapy.

Targeting genomic alterations in squamous cell lung cancer

Squamous cell lung cancer causes approximately 400,000 deaths worldwide per year. Identification of specific molecular alterations, such as activating mutations in the epidermal growth factor receptor kinase and echinoderm microtubule-associated protein-like 4/anaplastic lymphoma kinase fusions have led to significant therapeutic gains in patients with adenocarcinoma. However, meaningful therapeutic gains based on the molecular pathobiology of squamous cell lung cancer have not yet been realized. A comprehensive genomic characterization of 178 cases of squamous cell lung cancer has recently been reported. Squamous cell lung cancer appears to be characterized by a broader and more complex group of genomic alterations than adenocarcinoma. In this review, potentially targetable genes or pathways in squamous cell lung cancer are emphasized in relation to available therapeutic agents in development or active clinical trials. This organization of data will provide a framework for development for clinical investigation. Squamous cell lung cancer appears to be characterized by not only driver mutations in candidate genes but also gene copy number alterations resulting in tumor proliferation and survival. Better understanding of these genetic alterations and their use as therapeutic targets will require broad collaboration between industry, government, the cooperative groups, and academic institutions with the ultimate goal of rapid translation of scientific advancement to patient benefit.

Molecularly targeted agents as radiosensitizers in cancer therapy--focus on prostate cancer

As our understanding of the molecular pathways driving tumorigenesis improves and more druggable targets are identified, we have witnessed a concomitant increase in the development and production of novel molecularly targeted agents. Radiotherapy is commonly used in the treatment of various malignancies with a prominent role in the care of prostate cancer patients, and efforts to improve the therapeutic ratio of radiation by technologic and pharmacologic means have led to important advances in cancer care. One promising approach is to combine molecularly targeted systemic agents with radiotherapy to improve tumor response rates and likelihood of durable control. This review first explores the limitations of preclinical studies as well as barriers to successful implementation of clinical trials with radiosensitizers. Special considerations related to and recommendations for the design of preclinical studies and clinical trials involving molecularly targeted agents combined with radiotherapy are provided. We then apply these concepts by reviewing a representative set of targeted therapies that show promise as radiosensitizers in the treatment of prostate cancer.