Targeted therapy of kidney cancer: keeping the art around the algorithms

Chromosomal aberrations in renal cell carcinoma: An overview with implications for clinical practice

Chromosomal instability and aberrations are known in many cancers including renal cell carcinoma. Detailed understanding of these changes has led to an improved drug discovery and continued developments in other therapeutic options. Chromosomal aberrations have a potential to be used to monitor disease including prognostication. There has been a growing experience in cytogenetic techniques and gap between clinic and laboratory has narrowed significantly in the recent past. Nevertheless, more work on validation of these techniques, establishing threshold and interobserver agreement needs to be carried out for these diagnostic/prognostic tests before utilizing them in clinics as a part of “personalized medicine” care. The review presented here is a summary of common genetic disorders in renal cancer and some of acquired genetic changes which can be used as biomarkers. The review also describes basics of commonly used genetic techniques for wider clinical community involved in the management of renal cancer.

Genetic and Chromosomal Aberrations and Their Clinical Significance in Renal Neoplasms

The most common form of malignant renal neoplasms is renal cell carcinoma (RCC), which is classified into several different subtypes based on the histomorphological features. However, overlaps in these characteristics may present difficulties in the accurate diagnosis of these subtypes, which have different clinical outcomes. Genomic and molecular studies have revealed unique genetic aberrations in each subtype. Knowledge of these genetic changes in hereditary and sporadic renal neoplasms has given an insight into the various proteins and signalling pathways involved in tumour formation and progression. In this review, the genetic aberrations characteristic to each renal neoplasm subtype are evaluated along with the associated protein products and affected pathways. The potential applications of these genetic aberrations and proteins as diagnostic tools, prognostic markers, or therapeutic targets are also assessed.

Nuclear Receptor 4A1 (NR4A1) as a Drug Target for Renal Cell Adenocarcinoma

The orphan nuclear receptor NR4A1 exhibits pro-oncogenic activity in cancer cell lines. NR4A1 activates mTOR signaling, regulates genes such as thioredoxin domain containing 5 and isocitrate dehydrogenase 1 that maintain low oxidative stress, and coactivates specificity protein 1 (Sp1)-regulated pro-survival and growth promoting genes. Transfection of renal cell carcinoma (RCC) ACHN and 786-O cells with oligonucleotides that target NR4A1 results in a 40–60% decrease in cell proliferation and induction of apoptosis. Moreover, knockdown of NR4A1 in RCC cells decreased bcl-2, survivin and epidermal growth factor receptor expression, inhibited of mTOR signaling, induced oxidative and endoplasmic reticulum stress, and decreased TXNDC5 and IDH1. We have recently demonstrated that selected 1,1-bis(3'-indolyl)-1-(p-substituted phenyl)methane (C-DIM) compounds including the p-hydroxyphenyl (DIM-C-pPhOH) and p-carboxymethyl (DIM-C-pPhCO₂Me) analogs bind NR4A1 and act as antagonists. Both DIM-C-pPhOH and DIM-C-pPhCO₂Me inhibited growth and induced apoptosis in ACHN and 786-O cells, and the functional and genomic effects of the NR4A1 antagonists were comparable to those observed after NR4A1 knockdown. These results indicate that NR4A1 antagonists target multiple growth promoting and pro-survival pathways in RCC cells and in tumors (xenograft) and represent a novel chemotherapy for treating RCC.

Influence of ribosomal protein L39-L in the drug resistance mechanisms of lacrimal gland adenoid cystic carcinoma cells

BACKGROUND

Cancer constitutes a key pressure on public health regardless of the economy state in different countries. As a kind of highly malignant epithelial tumor, lacrimal gland adenoid cystic carcinoma can occur in any part of the body, such as salivary gland, submandibular gland, trachea, lung, breast, skin and lacrimal gland. Chemotherapy is one of the key treatment techniques, but drug resistance, especially MDR, seriously blunts its effects. As an element of the 60S large ribosomal subunit, the ribosomal protein L39-L gene appears to be documented specifically in the human testis and many human cancer samples of different origins.

MATERIALS AND METHODS

Total RNA of cultured drug-resistant and susceptible lacrimal gland adenoid cystic carcinoma cells was seperated, and real time quantitative RT-PCR were used to reveal transcription differences between amycin resistant and susceptible strains of lacrimal gland adenoid cystic carcinoma cells. Viability assays were used to present the amycin resistance difference in a RPL39-L transfected lacrimal gland adenoid cystic carcinoma cell line as compared to control vector and null-transfected lacrimal gland adenoid cystic carcinoma cell lines.

RESULTS

The ribosomal protein L39-L transcription level was 6.5-fold higher in the drug-resistant human lacrimal gland adenoid cystic carcinoma cell line than in the susceptible cell line by quantitative RT-PCR analysis. The ribosomal protein L39-L transfected cells revealed enhanced drug resistance compared to plasmid vector-transfected or null-transfected cells as determined by methyl tritiated thymidine (3H-TdR) incorporation.

CONCLUSIONS

The ribosomal protein L39-L gene could possibly have influence on the drug resistance mechanism of lacrimal gland adenoid cystic carcinoma cells.

Hereditary renal cell carcinoma: genetics, clinical features, and surgical considerations

OBJECTIVES

Hereditary renal cancer syndromes have been described and have illuminated novel methods to treat sporadic renal cell carcinoma. In this work, we aimed to review the genetic basis, molecular pathology and clinical manifestations of hereditary syndromes, as well as outline principles of surgical management and use of targeted therapy.

METHODS

We performed a comprehensive review of selected peer-reviewed publications regarding hereditary renal cancer syndromes, their genetic basis, and recommendations for surgical management.

RESULTS

The major syndromes contributing to hereditary renal cell carcinoma are discussed along with relevant literature guiding their management. The evolving surgical and molecular treatments are discussed.

CONCLUSIONS

Identification of genetic basis of hereditary carcinomas provides opportunity for targeted therapy of metastatic sporadic renal cell carcinoma. Appropriate and timely surgical management of hereditary renal cancers decreases the possibility of development of metastatic disease, and allows for preservation of renal function despite the need for repeat surgical interventions.