In cancer therapy, molecularly targeted agents have the potential to maximize antitumor efficacy while minimizing treatment-related toxicity. However, these agents may only be effective in specific tumor subtypes with defined genomic profiles. This emphasizes the importance of developing personalized cancer therapeutic strategies (i.e. through the use of companion diagnostic tests) to appropriately select and treat patients who are likely to benefit from specific targeted therapies, thus leading to improvements in clinical and safety outcomes. A potential biological target is the folate receptor (FR), which has been shown to be overexpressed on the surface of many cancers, including tumors of the lungs and ovaries. We carried out a literature search to identify how the FR can be a potential target for selected tumors, and how the FR expression can be exploited by targeted therapies. The two main therapeutic strategies for targeting the FR are based on the use of: (i) an anti-FR antibody (e.g. farletuzumab) and (ii) folate conjugates of folate-targeted chemotherapies and companion radiodiagnostic imaging agents (e.g. vintafolide and ^99mtechnetium-etarfolatide). Both of these strategies are being assessed in phase III trials. The important role that the FR plays in cancer development and progression has led to the development of FR-targeted therapeutic approaches. To date, the promising data observed in phase II clinical trials have not been confirmed in phase III studies. Accordingly, there is a need for further research in the refinement of patient selection and identification of new therapeutic combinations. In particular, the development of these targeted therapies requires reliable methods to be developed to detect FR-positive tumors in order to help select patients who may benefit from treatment.

Altered phosphatidylcholine (PC) metabolism in epithelial ovarian cancer (EOC) could provide choline-based imaging approaches as powerful tools to improve diagnosis and identify new therapeutic targets. The increase in the major choline-containing metabolite phosphocholine (PCho) in EOC compared with normal and nontumoral immortalized counterparts (EONT) may derive from (a) enhanced choline transport and choline kinase (ChoK)–mediated phosphorylation, (b) increased PC-specific phospholipase C (PC-plc) activity, and (c) increased intracellular choline production by PC deacylation plus glycerophosphocholine-phosphodiesterase (GPC-pd) or by phospholipase D (pld)–mediated PC catabolism followed by choline phosphorylation. Biochemical, protein, and mRNA expression analyses showed that the most relevant changes in EOC cells were (a) 12-fold to 25-fold ChoK activation, consistent with higher protein content and increased ChoKα (but not ChoKβ) mRNA expression levels; and (b) 5-fold to 17-fold PC-plc activation, consistent with higher, previously reported, protein expression. PC-plc inhibition by tricyclodecan-9-yl-potassium xanthate (D609) in OVCAR3 and SKOV3 cancer cells induced a 30% to 40% reduction of PCho content and blocked cell proliferation. More limited and variable sources of PCho could derive, in some EOC cells, from 2-fold to 4-fold activation of pld or GPC-pd. Phospholipase A₂ activity and isoform expression levels were lower or unchanged in EOC compared with EONT cells. Increased ChoKα mRNA, as well as ChoK and PC-plc protein expression, were also detected in surgical specimens isolated from patients with EOC. Overall, we showed that the elevated PCho pool detected in EOC cells primarily resulted from upregulation/activation of ChoK and PC-plc involved in PC byosinthesis and degradation, respectively. Cancer Res; 70(5); 2126–35

Head and neck cancer subtypes with biological and clinical relevance: Meta-analysis of gene-expression data Head and neck cancer subtypes with biological and clinical relevance: Meta-analysis of gene-expression data

The epidermal growth factor receptor (EGFR), a member of the ErbB family of receptor tyrosine kinases, is expressed in up to 70% of epithelial ovarian cancers (EOCs), where it correlates with poor prognosis. The majority of EOCs are diagnosed at an advanced stage, and at least 50% present malignant ascites. High levels of IL-6 have been found in the ascites of EOC patients and correlate with shorter survival. Herein, we investigated the signaling cascade led by EGFR activation in EOC and assessed whether EGFR activation could induce an EOC microenvironment characterized by pro-inflammatory molecules. In vitro analysis of EOC cell lines revealed that ligand-stimulated EGFR activated NFkB-dependent transcription and induced secretion of IL-6 and plasminogen activator inhibitor (PAI-1). IL-6/PAI-1 expression and secretion were strongly inhibited by the tyrosine kinase inhibitor AG1478 and EGFR silencing. A significant reduction of EGF-stimulated IL-6/PAI-1 secretion was also obtained with the NFkB inhibitor dehydroxymethylepoxyquinomicin. Of 23 primary EOC tumors from advanced-stage patients with malignant ascites at surgery, 12 co-expressed membrane EGFR, IL-6 and PAI-1 by immunohistochemistry; both IL-6 and PAI-1 were present in 83% of the corresponding ascites. Analysis of a publicly available gene-expression data set from 204 EOCs confirmed a significant correlation between IL-6 and PAI-1 expression, and patients with the highest IL-6 and PAI-1 co-expression showed a significantly shorter progression-free survival time (P=0.028). This suggests that EGFR/NFkB/IL-6-PAI-1 may have a significant impact on the therapy of a particular subset of EOC, and that IL-6/PAI-1 co-expression may be a novel prognostic marker.

Purpose: To identify the tumor portrait of the minority of head and neck squamous cell carcinoma (HNSCC) patients with recurrent–metastatic (RM) disease who upon treatment with platinum-based chemotherapy plus cetuximab present a long-lasting response. Experimental Design: The gene expression of pretreatment samples from 40 HNSCC-RM patients, divided in two groups [14 long-progression-free survival (PFS) and 26 short-PFS (median = 19 and 3 months, respectively)], was associated with PFS and was challenged against a dataset from metastatic colon cancer patients treated with cetuximab. For biologic analysis, we performed functional and subtype association using gene set enrichment analysis, associated biology across all currently available HNSCC signatures, and inferred drug sensitivity using data from the Cancer Genomic Project. Results: The identified genomic profile exhibited a significant predictive value that was essentially confirmed in the single publicly available dataset of cetuximab-treated patients. The main divergence between long- and short-PFS groups was based on developmental/differentiation status. The long-PFS patients are characterized by basal subtype traits such as strong EGFR signaling phenotype and hypoxic differentiation, further validated by the significantly higher association with the hypoxia metagene. The short-PFS patients presented a strong activation of RAS signaling confirmed in an in vitro model of two isogenic HNSCC cell lines sensitive or resistant to cetuximab. The predicted drug sensitivity for all four EGFR inhibitors was higher in long- versus short-PFS patients (P range: <0.0022–1e−07). Conclusions: Our data uncover the biology behind response to platinum-based chemotherapy plus cetuximab in RM-HNSCC cancer and may have translational implications improving treatment selection. Clin Cancer Res; 22(15); 3961–70. ©2016 AACR. See related commentary by Chau and Hammerman, p. 3710

To investigate the tumor fraction with cancer stem/tumor initiating cell (CSC/TIC) characteristics, we tested the human cervical carcinoma cell lines A431, Caski and SiHa, by growth as non-adherent spheres in specific media and aldehyde dehydrogenase (ALDH) enzymatic activity. A good correlation between the two parameters was observed and the highest levels were observed in A431 cell line that was selected for characterization of the CSC/TIC fraction. A431 parental cells already displayed characteristics common to CSC/TIC, such as sphere forming efficiency, adherent holoclone formation and high ALDH activity. Non-adherent spheres maintained or increased these properties, and, in particular, ALDH-positive fraction increased from 46 to 65% and a transient induction of stem cell markers such as Nanog, Nestin and Oct4 was observed. Furthermore, a significant increase of paraclone forming cells was observed, suggesting that differentiation took place inside sphere cell populations. As compared to parental cells, spheres were characterized by: (1) a ten-fold higher verapamil-sensitive side population fraction; (2) the appearance of a podoplanin-positive subpopulation characterized by a small cell size; (3) the ability to propagate tumors in nude mice at a lower cell dose. The global gene expression analysis demonstrated a strong and reversible modulation of 'sphere' phenotype in comparison to parental and sphere cells re-induced to adherent conditions. All together our results indicated that the growth of A431 cells as a non-adherent sphere was not sufficient by itself to define a stem-like population, but it was essential for the emergence of a small population of tumor cells with CSC properties.