Repurposing vitamin D for treatment of human malignancies via targeting tumor microenvironment

Tumor cells along with a small proportion of cancer stem cells exist in a stromal microenvironment consisting of vasculature, cancer-associated fibroblasts, immune cells and extracellular components. Recent epidemiological and clinical studies strongly support that vitamin D supplementation is associated with reduced cancer risk and favorable prognosis. Experimental results suggest that vitamin D not only suppresses cancer cells, but also regulates tumor microenvironment to facilitate tumor repression. In this review, we have outlined the current knowledge on epidemiological studies and clinical trials of vitamin D. Notably, we summarized and discussed the anticancer action of vitamin D in cancer cells, cancer stem cells and stroma cells in tumor microenvironment, providing a better understanding of the role of vitamin D in cancer. We presently re-propose vitamin D to be a novel and economical anticancer agent.

Relations between approved platinum drugs and non-coding RNAs in mesothelioma

Malignant mesothelioma diseases feature an increasing risk due to their severe forms and their association with asbestos exposure. Platinum(II) complexes such as cisplatin and carboplatin are clinically approved for the therapy of mesothelioma often in combination with antimetabolites such as pemetrexed or gemcitabine. It was observed that pathogenic properties of mesothelioma cells and the response of mesothelioma tumors towards platinum-based drugs are strongly influenced by non-coding RNAs, in particular, by small microRNAs (miRNAs) and long non-coding RNAs (lncRNAs). These non-coding RNAs controlled drug sensitivity and the development of tumor resistance towards platinum drugs. An overview of the interactions between platinum drugs and non-coding RNAs is given and the influence of non-coding RNAs on platinum drug efficacy in mesothelioma is discussed. Suitable non-coding RNA-modulating agents with potentially beneficial effects on cisplatin treatment of mesothelioma diseases are mentioned. The understanding of mesothelioma diseases concerning the interactions of non-coding RNAs and platinum drugs will optimize existing therapy schemes and pave the way to new treatment options in future.

Efficacy and safety of the hypoxia-activated prodrug TH-302 in combination with gemcitabine and nab-paclitaxel in human tumor xenograft models of pancreatic cancer

Tumors often contain hypoxic regions resistant to chemo- and radiotherapy. TH-302 (T) is an investigational hypoxia-activated prodrug that selectively releases the DNA cross-linker bromo-isophosphoramide mustard under hypoxic conditions. This study evaluated the efficacy and safety profile of combining T with gemcitabine (G) and nab-paclitaxel (nP) in human pancreatic ductal adenocarcinoma (PDAC) xenograft models in mice. Antitumor activity of the G + nP + T triplet was assessed and compared with T-alone or the G + nP doublet in the Hs766t, MIA PaCa-2, PANC-1, and BxPC-3 PDAC xenograft models. Efficacy was assessed by tumor growth kinetic analysis. Body weight, blood cell counts, blood chemistry, and the von Frey neuropathy assay were analyzed to evaluate safety profiles. Pharmacodynamic changes after the treatment were determined by immunohistochemistry of cell proliferation, DNA damage, apoptosis, hypoxia, and tumor stroma density. The G + nP + T triplet exhibited enhanced efficacy compared with T-alone or the G + nP doublet. Compared with vehicle (V), G + nP induced body weight loss, reduced neutrophil and lymphocyte counts, increased the levels of liver function parameters, and induced neurotoxicity. However, when T was added to G + nP, there was no statistically increased impairment compared to G + nP. The triplet significantly increased DNA damage, apoptosis, and tumor necrosis. Furthermore, the triplet further inhibited cell proliferation and reduced stroma density and intratumoral hypoxia. The triplet combination of G + nP + T exhibited superior efficacy but additive toxicity was not evident compared to the G + nP doublet in this study. This study provides a translational rationale for combining G, nP, and T in the clinical setting to assess efficacy and safety. A Phase I clinical trial of the triplet combination is currently underway (NCT02047500).

A phenotype from tumor stroma based on the expression of metalloproteases and their inhibitors, associated with prognosis in breast cancer

The objective of the present work was to evaluate the impact of the phenotype of both mononuclear inflammatory cells (MICs) and cancer-associated fibroblast (CAFs) in early breast cancer patients, specifically assessed as to their expression of MMP/TIMP relative to their position within the tumor (i.e., localization at the tumor center or invasive front) and the occurrence of distant metastases.. An immunohistochemical study was performed using tissue arrays and specific antibodies against matrix metalloproteinase (MMP)-1, -2, -7, -9, -11, -13 and -14, tissue inhibitors of metalloproteinase (TIMP)-1, -2 and -3, both at tumor center and at invasive front, in 107 patients with primary ductal invasive breast tumors. Data were analyzed by unsupervised hierarchical clustering analysis. Our results indicated that MMP-11 expression by MICs, and TIMP-2 expression by CAFs at either the tumor center or the invasive front, were the most potent independent prognostic factors for predicting the clinical outcome of patients. Using the unsupervised hierarchical clustering analysis, we found well-defined clusters of cases identifying subgroups of tumors showing a high molecular profile of MMPs/TIMPs expression by stromal cells (CAFs and MICs), both at the tumor center and at the invasive front, which were strongly associated with a higher prevalence of distant metastasis. In addition, we found combinations of these clusters defining subpopulations of breast carcinomas differing widely in their clinical outcome. The results presented here identify biologic markers useful to categorize patients into different subgroups based on their tumor stroma, which may contribute to improved understanding of the prognosis of breast cancer patients.