Targeted therapies of solid cancers: new options, new challenges

Protein drug target activation homogeneity in the face of intra-tumor heterogeneity: implications for precision medicine

Introduction: Recent studies indicated tumors may be comprised of heterogeneous molecular subtypes and incongruent molecular portraits may emerge if different areas of the tumor are sampled. This study explored the impact of intra-tumoral heterogeneity in terms of activation/phosphorylation of FDA approved drug targets and downstream kinase substrates.

Material and methods: Two independent sets of liver metastases from colorectal cancer were used to evaluate protein kinase-driven signaling networks within different areas using laser capture microdissection and reverse phase protein array.

Results: Unsupervised hierarchical clustering analysis indicated that the signaling architecture and activation of the MAPK and AKT-mTOR pathways were consistently maintained within different regions of the same biopsy. Intra-patient variability of the MAPK and AKT-mTOR pathway were <1.06 fold change, while inter-patients variability reached fold change values of 5.01.

Conclusions: Protein pathway activation mapping of enriched tumor cells obtained from different regions of the same tumor indicated consistency and robustness independent of the region sampled. This suggests a dominant protein pathway network may be activated in a high percentage of the tumor cell population. Given the genomic intra-tumoral variability, our data suggest that protein/phosphoprotein signaling measurements should be integrated with genomic analysis for precision medicine based analysis.

The Natural cAMP Elevating Compound Forskolin in Cancer Therapy: Is It Time?

Cancer is a major public health problem and the second leading cause of mortality around the world. Although continuous advances in the science of oncology and cancer research are now leading to improved outcomes for many cancer patients, novel cancer treatment options are strongly demanded. Naturally occurring compounds from a variety of vegetables, fruits, and medicinal plants have been shown to exhibit various anticancer properties in a number of in vitro and in vivo studies and represent an attractive research area for the development of new therapeutic strategies to fight cancer. Forskolin is a diterpene produced by the roots of the Indian plant Coleus forskohlii. The natural compound forskolin has been used for centuries in traditional medicine and its safety has also been documented in conventional modern medicine. Forskolin directly activates the adenylate cyclase enzyme, that generates cAMP from ATP, thus, raising intracellular cAMP levels. Notably, cAMP signaling, through the PKA-dependent and/or -independent pathways, is very relevant to cancer and its targeting has shown a number of antitumor effects, including the induction of mesenchymal-to-epithelial transition, inhibition of cell growth and migration and enhancement of sensitivity to conventional antitumor drugs in cancer cells. Here, we describe some features of cAMP signaling that are relevant to cancer biology and address the state of the art concerning the natural cAMP elevating compound forskolin and its perspectives as an effective anticancer agent. J. Cell. Physiol. 232: 922-927, 2017. © 2016 Wiley Periodicals, Inc.

Preparation and Evaluation of a Novel Class of Amphiphilic Amines as Antitumor Agents and Nanocarriers for Bioactive Molecules

Purpose

We describe a novel class of antitumor amphiphilic amines (RCn) based on a tricyclic amine hydrophilic head and a hydrophobic linear alkyl tail of variable length.

Methods

We tested the lead compound, RC16, for cytotoxicity and mechanism of cell death in several cancer cell lines, anti tumor efficacy in mouse tumor models, and ability to encapsulate chemotherapy drugs.

Results

These compounds displayed strong cytotoxic activity against cell lines derived from both pediatric and adult cancers. The IC50 of the lead compound, RC16, for normal cells including human keratinocytes, human fibroblasts and human umbilical vein endothelial cells was tenfold higher than for tumor cells. RC16 exhibited significant antitumor effects in vivo using several human xenografts and a metastatic model of murine neuroblastoma by both intravenous and oral administration routes. The amphiphilic character of RC16 triggered a spontaneous molecular self-assembling in water with formation of micelles allowing complexation of Doxorubicin, Etoposide and Paclitaxel. These micelles significantly improved the in vitro antitumor activity of these drugs as the enhancement of their aqueous solubility also improved their biologic availability.

Conclusions

RC16 and related amphiphilic amines may be useful as a novel cancer treatment.

Electronic supplementary material

The online version of this article (doi:10.1007/s11095-016-1999-9) contains supplementary material, which is available to authorized users.

F-18 fluoromisonidazole for imaging tumor hypoxia: imaging the microenvironment for personalized cancer therapy

Hypoxia in solid tumors is one of the seminal mechanisms for developing aggressive trait and treatment resistance in solid tumors. This evolutionarily conserved biological mechanism along with derepression of cellular functions in cancer, although resulting in many challenges, provide us with opportunities to use these adversities to our advantage. Our ability to use molecular imaging to characterize therapeutic targets such as hypoxia and apply this information for therapeutic interventions is growing rapidly. Evaluation of hypoxia and its biological ramifications to effectively plan appropriate therapy that can overcome the cure-limiting effects of hypoxia provides an objective means for treatment selection and planning. Fluoromisonidazole (FMISO) continues to be the lead radiopharmaceutical in PET imaging for the evaluation, prognostication, and quantification of tumor hypoxia, one of the key elements of the tumor microenvironment. FMISO is less confounded by blood flow, and although the images have less contrast than FDG-PET, its uptake after 2 hours is an accurate reflection of inadequate regional oxygen partial pressure at the time of radiopharmaceutical administration. By virtue of extensive clinical utilization, FMISO remains the lead candidate for imaging and quantifying hypoxia. The past decade has seen significant technological advances in investigating hypoxia imaging in radiation treatment planning and in providing us with the ability to individualize radiation delivery and target volume coverage. The presence of widespread hypoxia in the tumor can be effectively targeted with a systemic hypoxic cell cytotoxin or other agents that are more effective with diminished oxygen partial pressure, either alone or in combination. Molecular imaging in general and hypoxia imaging in particular will likely become an important in vivo imaging biomarker of the future, complementing the traditional direct tissue sampling methods by providing a snap shot of a primary tumor and metastatic disease and in following treatment response and will serve as adjuncts to personalized therapy.

Flexible lab-tailored cut-offs for suitability of formalin-fixed tumor samples for diagnostic mutational analyses

The selection of proper tissues from formalin-fixed and paraffin-embedded tumors before diagnostic molecular testing is responsibility of the pathologist and represents a crucial step to produce reliable test results. The international guidelines suggest two cut-offs, one for the percentage and one for the number of tumor cells, in order to enrich the tumor content before DNA extraction. The aim of the present work was two-fold: to evaluate to what extent a low percentage or absolute number of tumor cells can be qualified for somatic mutation testing; and to determine how assay sensitivities can guide pathologists towards a better definition of morphology-based adequacy cut-offs. We tested 1797 tumor specimens from melanomas, colorectal and lung adenocarcinomas. Respectively, their BRAF, K-RAS and EGFR genes were analyzed at specific exons by mutation-enriched PCR, pyrosequencing, direct sequencing and real-time PCR methods. We demonstrate that poorly cellular specimens do not modify the frequency distribution of either mutated or wild-type DNA samples nor that of specific mutations. This observation suggests that currently recommended cut-offs for adequacy of specimens to be processed for molecular assays seem to be too much stringent in a laboratory context that performs highly sensitive routine analytical methods. In conclusion, new cut-offs are needed based on test sensitivities and documented tumor heterogeneity.

Avasimibe encapsulated in human serum albumin blocks cholesterol esterification for selective cancer treatment

Undesirable side effects remain a significant challenge in cancer chemotherapy. Here we report a strategy for cancer-selective chemotherapy by blocking acyl-CoA cholesterol acyltransferase-1 (ACAT-1)-mediated cholesterol esterification. To efficiently block cholesterol esterification in cancer in vivo, we developed a systemically injectable nanoformulation of avasimibe (a potent ACAT-1 inhibitor), called avasimin. In cell lines of human prostate, pancreatic, lung, and colon cancer, avasimin significantly reduced cholesteryl ester storage in lipid droplets and elevated intracellular free cholesterol levels, which led to apoptosis and suppression of proliferation. In xenograft models of prostate cancer and colon cancer, intravenous administration of avasimin caused the concentration of avasimibe in tumors to be 4-fold higher than the IC50 value. Systemic treatment of avasimin notably suppressed tumor growth in mice and extended the length of survival time. No adverse effects of avasimin to normal cells and organs were observed. Together, this study provides an effective approach for selective cancer chemotherapy by targeting altered cholesterol metabolism of cancer cells.

Inhibition of human diffuse large B-cell lymphoma growth by JC polyomavirus-like particles delivering a suicide gene

Background

Diffuse large B-cell lymphoma (DLBCL) is one of the most common types of aggressive B-cell non-Hodgkin lymphoma. About one-third of patients are either refractory to the treatment or experience relapse afterwards, pointing to the necessity of developing other effective therapies for DLBCL. Human B-lymphocytes are susceptible to JC polyomavirus (JCPyV) infection, and JCPyV virus-like particles (VLPs) can effectively deliver exogenous genes to susceptible cells for expression, suggesting the feasibility of using JCPyV VLPs as gene therapy vectors for DLBCL.

Methods

The JCPyV VLPs packaged with a GFP reporter gene were used to infect human DLBCL cells for gene delivery assay. Furthermore, we packaged JCPyV VLPs with a suicide gene encoding thymidine kinase (TK) to inhibit the growth of DLBCL in vitro and in vivo.

Results

Here, we show that JCPyV VLPs effectively entered human germinal center B-cell-like (GCB-like) DLBCL and activated B-cell-like (ABC-like) DLBCL and expressed the packaged reporter gene in vitro. As measured by the MTT assay, treatment with tk-VLPs in combination with gancyclovir (GCV) reduced the viability of DLBCL cells by 60%. In the xenograft mouse model, injection of tk-VLPs through the tail vein in combination with GCV administration resulted in a potent 80% inhibition of DLBCL tumor nodule growth.

Conclusions

Our results demonstrate the effectiveness of JCPyV VLPs as gene therapy vectors for human DLBCL and provide a potential new strategy for the treatment of DLBCL.

New strategies in personalized medicine for solid tumors: molecular markers and clinical trial designs

The delineation of signaling pathways to understand tumor biology combined with the rapid development of technologies that allow broad molecular profiling and data analysis has led to a new era of personalized medicine in oncology. Many academic institutions now routinely profile patients and discuss their cases in meetings of personalized medicine tumor boards before making treatment recommendations. Clinical trials initiated by pharmaceutical companies often require specific markers for enrollment or at least explore multiple options for future markers. In addition to the still small number of targeted agents that are approved for the therapy of patients with histological and molecularly defined tumors, a broad range of novel targeted agents in development are undergoing clinical studies with companion profiling to determine the best-responding patient population. Although the present focus of profiling lies in genetic analyses, additional tests of RNA, protein, and immune parameters are being developed and incorporated in clinical research, and these methods are likely to contribute significantly to future patient selection and treatment approaches. As the advances in tumor biology and human genetics have identified promising tumor targets, the ongoing clinical evaluation of novel agents will now need to show if the promise can be translated into benefit for patients.

Potential therapeutic targets for oral cancer: ADM, TP53, EGFR, LYN, CTLA4, SKIL, CTGF, CD70

In India, oral cancer has consistently ranked among top three causes of cancer-related deaths, and it has emerged as a top cause for the cancer-related deaths among men. Lack of effective therapeutic options is one of the main challenges in clinical management of oral cancer patients. We interrogated large pool of samples from oral cancer gene expression studies to identify potential therapeutic targets that are involved in multiple cancer hallmark events. Therapeutic strategies directed towards such targets can be expected to effectively control cancer cells. Datasets from different gene expression studies were integrated by removing batch-effects and was used for downstream analyses, including differential expression analysis. Dependency network analysis was done to identify genes that undergo marked topological changes in oral cancer samples when compared with control samples. Causal reasoning analysis was carried out to identify significant hypotheses, which can explain gene expression profiles observed in oral cancer samples. Text-mining based approach was used to detect cancer hallmarks associated with genes significantly expressed in oral cancer. In all, 2365 genes were detected to be differentially expressed genes, which includes some of the highly differentially expressed genes like matrix metalloproteinases (MMP-1/3/10/13), chemokine (C-X-C motif) ligands (IL8, CXCL-10/-11), PTHLH, SERPINE1, NELL2, S100A7A, MAL, CRNN, TGM3, CLCA4, keratins (KRT-3/4/13/76/78), SERPINB11 and serine peptidase inhibitors (SPINK-5/7). XIST, TCEAL2, NRAS and FGFR2 are some of the important genes detected by dependency and causal network analysis. Literature mining analysis annotated 1014 genes, out of which 841 genes were statistically significantly annotated. The integration of output of various analyses, resulted in the list of potential therapeutic targets for oral cancer, which included targets such as ADM, TP53, EGFR, LYN, CTLA4, SKIL, CTGF and CD70.

Glucose-regulated protein 78 and heparanase expression in oral squamous cell carcinoma: correlations and prognostic significance

BACKGROUND

The aim of the present study was to investigate the expression of glucose-related protein 78 (GRP78) and heparanase (HPA) in oral squamous cell carcinoma (OSCC) and their relationship with clinicopathological parameters and potential implications for survival.

METHODS

A total of 46 patients with OSCC and 10 normal individuals were recruited for the study. GRP78 and HPA expression were determined in the lesion tissues using immunohistochemical analysis. The correlation between GRP78 and HPA was assessed using the Spearman correlation analysis. The associations of GRP78 and HPA with clinicopathological characteristics and survival were examined using the x2-test, Kaplan-Meier, or Cox regression.

RESULTS

Patients with OSCC showed a statistically significant higher prevalence of GRP78 and HPA expression than normal oral tissues. GRP78 and HPA expression was positively correlated with size, TNM stage, histological grade, lymphatic metastasis, and distant metastasis in OSCC patients. GRP78 expression was also positively correlated with HPA expression. Positive GRP78 and HPA expression was inversely correlated with survival in OSCC patients.

CONCLUSIONS

HPA expression was found to be positively correlated with GRP78 expression. GRP78 and HPA are biomarkers that may have the potential to guide the treatment of oral cancer patients.

Breast cancer, DPYD mutations and capecitabine-related ileitis: description of two cases and a review of the literature

Despite many treatment advances, metastatic breast cancer remains an incurable disease and is the third leading cause of cancer-related deaths in Europe. Capecitabine has become a standard treatment option for metastatic breast cancer, as a single agent or in combination. Hand-foot syndrome and diarrhoea are the most frequently reported side effects, while capecitabine-related ileitis is very rare. Deficiency of dihydropyrimidine dehydrogenase activity leads to severe toxicities after administration of 5-fluorouracil or its prodrugs. We report two cases of patients with metastatic breast cancer who developed ileitis after treatment with capecitabine. One patient had a DPYD gene abnormality.