Cancers, Volume 8, Issue 1 (January 2016) – 18 articles

Cutaneous melanoma is one of the most aggressive forms of skin cancer, and is correlated with a large proportion of skin cancer-related deaths. Therapy for cutaneous melanoma has advanced greatly through careful identification of therapeutic targets and the development of novel immunotherapeutic approaches. The identification of BRAF as well as other driver mutations, have allowed for a specialized approach to treatment. In addition, immune checkpoint inhibition has dramatically changed the treatment landscape over the past 5–10 years. The successful targeting of CTLA-4, as well as PD-1/PD-L1, has been translated into meaningful clinical benefit for patients, with multiple other potential agents in development. Systemic therapy for cutaneous melanoma is becoming more nuanced and often takes a multifaceted strategy. This review aims to discuss the benefits and limitations of current therapies in systemic melanoma treatment as well as areas of future development. Full article

The health awareness recently shown by consumers has led to a demand for health beneficial products. In particular, researchers are currently focusing their studies on the search for foods for cancer prevention activity. In the present work, we study comparatively the effect of two different processing methods on the contents of phenolic compounds (i.e., ellagic acid, myricetin, quercetin and kaempferol) with antioxidant and antitumor properties in strawberry jams. In turn, the results obtained were compared with those of unprocessed fruit. Additionally carcinogenic heat-induced compounds formed by the two jam making methods were evaluated. Decreases of total ellagic acid from 138.4 µg/g to 86.5 µg/g were measured in jam as compared with the intact fruit. Even higher losses of up to 90% of total flavonols were found in strawberry after the jam-making process. A comparison between the two processing methods proved shorter heating periods (around 60 min) even at temperatures as high as 100 °C enabled losses of antioxidant phenolics to be minimized. Carcinogenic heat-induced volatile compounds, mainly Maillard reaction products, were formed as a result of thermal treatment during jam processing. However, shorter heating periods also helped reduce the formation of these harmful compounds. These results are deeply discussed. From a practical standpoint, the processing conditions here proposed can be used by industry to obtain strawberry jam with higher content of antioxidant flavonoids and, at the same time, reduced amounts of carcinogenic compounds. Full article

Glioblastoma (GBM) is the most common and most aggressive malignant primary brain tumor in adults. In spite of multimodal therapy concepts, consisting of surgery, radiotherapy and chemotherapy, the median survival, merely 15–18 months, is still poor. Mechanisms for resistance of GBM to radio(chemo)therapy are not fully understood yet and due to the genetic heterogeneity within the tumor including radiation-resistant tumor stem cells, there are several factors leading to therapy failure. Recent research revealed that, hypoxia during radiation and miRNAs may adversely affect the therapeutic response to radiotherapy. Further molecular alterations and prognostic markers like the DNA-repair protein O6-methylguanine-DNA methyltransferase (MGMT), anti-apoptotic molecular chaperones, and/or the activity of aldehyde dehydrogenase 1 (ALDH1) have also been identified to play a role in the sensitivity to cytostatic agents. Latest approaches in the field of radiotherapy to use particle irradiation or dose escalation strategies including modern molecular imaging, however, need further evaluation with regard to long-term outcome. In this review we focus on current information about the mechanisms and markers that mediate resistance to radio(chemo)therapy, and discuss the opportunities of Innovative Radiotherapy (iRT) concepts to improve treatment options for GBM patients. Full article

There is an increasing focus on the tumor microenvironment in carcinogenesis. Integrins are important receptors and adhesion molecules in this environment and have been shown to be involved in cell adhesion, proliferation, differentiation and migration. The present study aimed to evaluate the effect of stromal integrin β3-deficiency on tumor growth, angiogenesis, interstitial fluid pressure (PIF), fibrosis and metastasis in a murine breast cancer (4T1) and a prostate tumor (RM11) model. We showed that stromal integrin β3-deficiency led to an elevation in PIF that correlated to a shift towards thicker collagen fibrils in the 4T1 mammary tumor. In the RM11 prostate carcinoma model there was no effect of integrin β3-deficiency on PIF and collagen fibril thickness. These findings support the notion that changes in the collagen scaffold influence PIF, and also indicate that there must be important crosstalk between the stroma and tumor cells, in a tumor cell line specific manner. Furthermore, stromal integrin β3-deficiency had no effect on tumor growth or angiogenesis in both tumor models and no effect on lung metastasis in the 4T1 mammary tumor model. In conclusion, the stromal β3 integrin influence PIF, possibly via its effect on the structure of the collagen network, in a tumor cell line dependent manner. Full article

Neuroblastoma, the most common extracranial solid tumor of childhood, continues to carry a dismal prognosis for children diagnosed with advanced stage or relapsed disease. This review focuses upon factors responsible for cell proliferation in neuroblastoma including transcription factors, kinases, and regulators of the cell cycle. Novel therapeutic strategies directed toward these targets in neuroblastoma are discussed. Full article

An increasing proportion of patients requiring treatment for malignancy are elderly, which has created new challenges for oncologic surgeons. Aging is associated with an increasing prevalence of frailty and comorbidities that may affect the outcome of surgical procedures. By decreasing complications and shortening length of hospital stay without affecting oncologic safety, surgery performed using the robot, rather than traditional laparotomy, improves the chances of a better outcome in our growing elderly populations. In addition to age, surgeons should take into account factors, such as frailty and comorbidities that correlate with outcome. Full article

Vascular disrupting agents (VDAs) represent a relatively distinct class of agents that target established blood vessels in tumors. In this study, we examined the preclinical activity of the second-generation VDA OXi4503 against human head and neck squamous cell carcinoma (HNSCC). Studies were performed in subcutaneous and orthotopic FaDu-luc HNSCC xenografts established in immunodeficient mice. In the subcutaneous model, bioluminescence imaging (BLI) along with tumor growth measurements was performed to assess tumor response to therapy. In mice bearing orthotopic tumors, a dual modality imaging approach based on BLI and magnetic resonance imaging (MRI) was utilized. Correlative histologic assessment of tumors was performed to validate imaging data. Dynamic BLI revealed a marked reduction in radiance within a few hours of OXi4503 administration compared to baseline levels. However, this reduction was transient with vascular recovery observed at 24 h post treatment. A single injection of OXi4503 (40 mg/kg) resulted in a significant (p < 0.01) tumor growth inhibition of subcutaneous FaDu-luc xenografts. MRI revealed a significant reduction (p < 0.05) in volume of orthotopic tumors at 10 days post two doses of OXi4503 treatment. Corresponding histologic (H&E) sections of Oxi4503 treated tumors showed extensive areas of necrosis and hemorrhaging compared to untreated controls. To the best of our knowledge, this is the first report, on the activity of Oxi4503 against HNSCC. These results demonstrate the potential of tumor-VDAs in head and neck cancer. Further examination of the antivascular and antitumor activity of Oxi4503 against HNSCC alone and in combination with chemotherapy and radiation is warranted. Full article

We recently developed Kochi Oxydol-Radiation Therapy for Unresectable Carcinomas (KORTUC) as a strategy to increase intratumoral oxygen concentrations and degrade antioxidant enzymes such as peroxidase and catalase. We then developed KORTUC II, which uses sodium hyaluronate containing hydrogen peroxide as a radiosensitizer. KORTUC II requires twice-weekly administration to sustain its effects, but decreasing the frequency of radiosensitizer injections to once-weekly would reduce the burden on the patients and the physicians. The goal of this study was thus to develop a new formulation of KORTUC (New KORTUC) that only requires once-weekly administration. We performed experimental studies using a mouse tumor model and biodegradable hydrogel. C3H/He mice were allocated to control, KORTUC, or hydrogel groups. At 72 h after injection, each tumor was irradiated with a 6 MeV electron beam to a total dose of 30 Gy. During a 62-day observation period, changes in tumor volume and survival rates were assessed in each group. Tumor growth rate was slowest in the hydrogel groups. These data suggest that hydrogel could represent a useful adjunct as a long-acting radiosensitizer in place of sodium hyaluronate. New KORTUC, which contains hydrogen peroxide and hydrogel, exerted a radiosensitizing effect that persisted beyond 72 h following injection of the agent. Use of this new formulation allows radiosensitizer injections to be performed once-weekly with good effect. Full article

Dear authors, reviewers, and readers of Cancers, It gives me great pleasure to welcome you to the latest issue of Cancers, for which I now serve as Editor-in-Chief. First, thanks are due to my predecessor and the founding Editor-in-Chief, Dr. Robert Weiss. [...] Full article

The connection between epithelial-mesenchymal (E-M) plasticity and cancer stem cell (CSC) properties has been paradigm-shifting, linking tumor cell invasion and metastasis with therapeutic recurrence. However, despite their importance, the molecular pathways involved in generating invasive, metastatic, and therapy-resistant CSCs remain poorly understood. The enrichment of cells with a mesenchymal/CSC phenotype following therapy has been interpreted in two different ways. The original interpretation posited that therapy kills non-CSCs while sparing pre-existing CSCs. However, evidence is emerging that suggests non-CSCs can be induced into a transient, drug-tolerant, CSC-like state by chemotherapy. The ability to transition between distinct cell states may be as critical for the survival of tumor cells following therapy as it is for metastatic progression. Therefore, inhibition of the pathways that promote E-M and CSC plasticity may suppress tumor recurrence following chemotherapy. Here, we review the emerging appreciation for how plasticity confers therapeutic resistance and tumor recurrence. Full article

Cancer stem cells (CSCs) are a subpopulation of tumor cells endowed with self-renewal properties and the capacity to dynamically adapt to physiological changes that occur in the tumor microenvironment. CSCs play a central role in resistance to therapy and long-term disease recurrence. Better characterization and understanding of the available in vitro tools to study the biology of CSCs will improve our knowledge of the processes underlying tumor response to therapy, and will help in the screening and development of novel strategies targeting CSCs. We investigated the behavior of different populations of head and neck CSCs grown under ultra-low adhesion conditions. We found that invasion and adhesion differ among tumorsphere subtypes (holospheres, merospheres and paraspheres), and their tumor cell progeny also harbor distinct self-renewal and clonogenic potentials. Furthermore, holospheres contained higher numbers of head and neck CSCs, as detected by the CD44 cancer stem cell marker and aldehyde dehydrogenase (ALDH) enzymatic activity. In addition, holospheres showed reduced proliferation (Ki67), hypoacetylation of histones, and increased expression of the BMI-1 epithelial stem cell marker, suggesting activation of stem cell programs. Collectively, our results suggest that holospheres enrich a specific population of CSCs with enhanced “stemness” and invasive potential. Full article

Background: Elderly patients receiving anticancer drugs may have an increased risk to develop treatment-related toxicities compared to their younger peers. However, a potential pharmacokinetic (PK) basis for this increased risk has not consistently been established yet. Therefore, the objective of this study was to systematically review the influence of age on the PK of anticancer agents frequently administered to elderly breast cancer patients. Methods: A literature search was performed using the PubMed electronic database, Summary of Product Characteristics (SmPC) and available drug approval reviews, as published by EMA and FDA. Publications that describe age-related PK profiles of selected anticancer drugs against breast cancer, excluding endocrine compounds, were selected and included. Results: This review presents an overview of the available data that describe the influence of increasing age on the PK of selected anticancer drugs used for the treatment of breast cancer. Conclusions: Selected published data revealed differences in the effect and magnitude of increasing age on the PK of several anticancer drugs. There may be clinically-relevant, age-related PK differences for anthracyclines and platina agents. In the majority of cases, age is not a good surrogate marker for anticancer drug PK, and the physiological state of the individual patient may better be approached by looking at organ function, Charlson Comorbidity Score or geriatric functional assessment. Full article

Neuroblastoma, a solid tumor arising from neural crest cells, accounts for over 15% of all pediatric cancer deaths. The interaction of neuroblastoma cancer-initiating cells with their microenvironment likely plays an integral role in the maintenance of resistant disease and tumor relapse. In this review, we discuss the interaction between neuroblastoma cancer-initiating cells and the elements of the tumor microenvironment and how these interactions may provide novel therapeutic targets for this difficult to treat disease. Full article

The development and progression of malignant tumors likely result from consecutive accumulation of genetic alterations, including dysfunctional tumor suppressor genes. However, the signaling mechanisms that underlie the development of tumors have not yet been completely elucidated. Discovery of novel tumor-related genes plays a crucial role in our understanding of the development and progression of malignant tumors. Chromosome engineering technology based on microcell-mediated chromosome transfer (MMCT) is an effective approach for identification of tumor suppressor genes. The studies have revealed at least five tumor suppression effects. The discovery of novel tumor suppressor genes provide greater understanding of the complex signaling pathways that underlie the development and progression of malignant tumors. These advances are being exploited to develop targeted drugs and new biological therapies for cancer. Full article

Endoglin overexpression is associated with highly proliferative tumor endothelium and also with some tumors, including melanoma. Its targeting has anti-tumor effectiveness, which can also be obtained by RNA interference. The aim of our study was to explore the anti-tumor effectiveness of endoglin silencing by electrotransfer of plasmid DNA encoding short hairpin RNA against endoglin in two murine B16 melanoma variants with different metastatic potential on cells, spheroids and subcutaneous tumors in mice. The results demonstrate that endoglin silencing with gene electrotransfer reduces the proliferation, survival and migration of melanoma cells and also has anti-tumor effectiveness, as the therapy resulted in a high percentage of tumor cures (23% and 58% on B16F1 and B16F10 tumors, respectively). The effectiveness of the therapy correlated with endoglin expression in melanoma cells; in vitro the effects were more pronounced in B16F1 cells, which express more endoglin than B16F10. However, the opposite was observed in vivo in tumors, where there was a higher expression of endoglin and better anti-tumor effectiveness in the B16F10 tumor. In conclusion, targeting endoglin for the treatment of melanoma seems to be a concept worthy of further exploration due to the increased therapeutic effect of the therapy based on simultaneous vascular targeting and its direct effect on tumor cells. Full article

The inside of a tumor often contains a hypoxic area caused by a limited supply of molecular oxygen due to aberrant vasculature. Hypoxia-inducible factors (HIFs) are major transcription factors that are required for cancer cells to adapt to such stress conditions. HIFs, complexed with the aryl hydrocarbon receptor nuclear translocator, bind to and activate target genes as enhancers of transcription. In addition to this common mechanism, the induction of the unfolded protein response and mTOR signaling in response to endoplasmic reticulum stress is also known to be involved in the adaptation to hypoxia conditions. Sp1 is a ubiquitously-expressed transcription factor that plays a vital role in the regulation of numerous genes required for normal cell function. In addition to the well-characterized stress response mechanisms described above, increasing experimental evidence suggests that Sp1 and HIFs collaborate to drive gene expression in cancer cells in response to hypoxia, thereby regulating additional adaptive responses to cellular oxygen deficiency. However, these characteristics of Sp1 and their biological merits have not been summarized. In this review, we will discuss the diverse mechanisms of transcriptional regulation by Sp1 and their potential involvement in the adaptive response of cancer cells to hypoxic tumor microenvironments. Full article

Background: We have developed a new radiosensitization treatment called Kochi Oxydol-Radiation Therapy for Unresectable Carcinomas, Type II (KORTUC II). Using KORTUC II, we performed breast-conserving treatment (BCT) without any surgical procedure for elderly patients with breast cancer in stages I/II or patients refusing surgery. Since surgery was not performed, histological confirmation of the primary tumor region following KORTUC II treatment was not possible. Therefore, to precisely evaluate the response to this new therapy, a detailed diagnostic procedure is needed. The goal of this study was to evaluate the therapeutic response to KORTUC II treatment in patients with stage I/II breast cancer using annual breast contrast-enhanced (CE) magnetic resonance imaging (MRI). Methods: Twenty-one patients with stage I/II breast cancer who were elderly and/or refused surgery were enrolled in this study. All patients underwent MRI prior to and at 3 to 6 months after KORTUC II, and then approximately biannually thereafter. Findings from MRI were compared with those from other diagnostic modalities performed during the same time period. Results: KORTUC II was well tolerated, with minimal adverse effects. All of 21 patients showed a clinically complete response (cCR) on CE MRI. The mean period taken to confirm cCR on the breast CE MRI was approximately 14 months. The mean follow-up period for the patients was 61.9 months at the end of October 2014. Conclusions: The therapeutic effect of BCT using KORTUC II without surgery could be evaluated by biannual CE MRI evaluations. Approximately 14 months were required to achieve cCR in response to this therapy. Full article