KL. Powell, AS. Stevens, SJ. Ralph, “Development of a potent melanoma vaccine capable of stimulating CD8+ T-cells independently of dendritic cells in a mouse model.,” Cancer Immunology, Immunotherapy, vol 64, no. 7, pp. 861-872, July 2015.
At present, there are no vaccines approved for the prevention or treatment of malignant melanoma, despite the amount of time and resources that has been invested. In this study, we aimed to develop a self-contained vaccine capable of directly stimulating anticancer CD8+ T-cell immune responses. To achieve this, three whole-cell melanoma vaccines were developed expressing 4-1BBL or B7.1 T-cell co-stimulatory molecules individually or in combination. The ability of engineered vaccine cell lines to stimulate potent anticancer immune responses in C57BL/6 mice was assessed. Mice vaccinated with cells overexpressing both 4-1BBL and B7.1 (B16-F10-4-1BBL-B7.1-IFNγ/β anticancer vaccine) displayed the greatest increases in CD8+ T-cell populations (1.9-fold increase versus control within spleens), which were efficiently activated following antigenic stimulation, resulting in a 10.7-fold increase in cancer cell cytotoxicity relative to control. The enhanced immune responses in B16-F10-4-1BBL-B7.1-IFNγ/β-vaccinated mice translated into highly efficient rejection of live tumour burdens and conferred long-term protection against repeated tumour challenges, which were likely due to enhanced effector memory T-cell populations. Similar results were observed when dendritic cell (DC)-deficient LTα−/− mice were treated with the B16-F10-4-1BBL-B7.1-IFNγ/β anticancer vaccine, suggesting that the vaccine can directly stimulate CD8+ T-cell responses in the context of severely reduced DCs. This study shows that the B16-F10-4-1BBL-B7.1-IFNγ/β anticancer vaccine acted as a highly effective antigen-presenting cell and is likely to be able to directly stimulate CD8+ T-cells, without requiring co-stimulatory signals from either CD4+ T-cells or DCs, and warrants translation of this technology into the clinical setting.
PA. Ascierto, “Immunotherapies and novel combinations: the focus of advances in the treatment of melanoma.,”Cancer Immunology, Immunotherapy, vol. 64, no. 3, pp. 271‐274, March 2015.
Since 2011, the approval of four different classes of novel drugs (the anti‐CTLA‐4 agent, ipilimumab; BRAF inhibitors [BRAFi]; MEK inhibitors [MEKi]; and the anti‐PD‐1 drug, pembrolizumab) has revolutionized the care of advanced melanoma, with the disease becoming a model for the development of new treatments for other types of cancer. Further advances in the treatment of melanoma represented some of the key highlights of the European Society of Medical Oncology (ESMO) 2014 congress. The first phase III trial of an anti‐PD‐1 agent to report the CA209‐037 study included 405 patients with metastatic melanoma previously treated with ipilimumab who were randomized 2:1 to receive nivolumab 3 mg/kg every 2 weeks or investigator’s choice chemotherapy. Nivolumab was associated with a higher response rate than chemotherapy and was well tolerated, with adverse events mostly low grade and manageable using recommended treatment algorithms. New data on other immunotherapies, namely ipilimumab and pembrolizumab, were also reported. In addition, outside of immunotherapy, combination approaches involving targeted agents were also a major focus of ESMO this year, with two major phase III studies of combined BRAF inhibition and MEK inhibition being reported. Overall, new clinical trial findings reported at ESMO further endorse the view that melanoma, given the continued development of novel, effective compounds, can accurately be described as the most “dynamic” field of oncology at present.
D. Wolf, A.Heine, P. Brossart, “Implementing combinatorial immunotherapeutic regimens against cancer: The concept of immunological conditioning.,” Oncoimmunology, vol. 1, no. 3, p. 1, 2014.
Harnessing the host immune system to eradicate cancer has a high therapeutic potential. One paradigm of anticancer immunotherapy is represented by allogeneic stem cell transplantation. In this setting, the host must be conditioned prior to transplantation, allowing for engraftment and subsequent graft‐vs.‐tumor reactivity. Conditioning may also be a prerequisite for the efficacy of other immunotherapeutic regimens. In particular, tumor debulking followed by conditioning (aimed at blocking endogenous inhibitory stimuli, for instance upon the depletion of regulatory T cells or the inhibition of immune checkpoints) and subsequent immunization (for instance by means of patient‐tailored vaccines) based on innovative adjuvants (such as RIG‐I ligands) may allow for the elicitation of superior antitumor immune responses. Repetitive boosting might then maintain immunosurveillance. An intense wave of investigation on the optimal timing of immunostimulatory interventions with respect to the administration of immunogenic chemotherapeutics and on the use of small drugs that promote efficient antitumor immune responses will end up in the generation of highly effective immunotherapeutic anticancer regimens.
SJ. Ralph, ʺAn update on malignant melanoma vaccine research: insights into mechanisms for improving the design and potency of melanoma therapeutic vaccines.,ʺ American Journal of Clinical Dermatology, vol. 8, no. 3, pp. 123‐41, 2007.
Currently, cancer vaccine therapy for melanoma has a 2‐fold focus. On the one hand, advances have been aimed at improving the effectiveness of melanoma vaccines based on a greater understanding of melanoma tumor cell biology. On the other hand, there is increasing evidence that the immune system, our defense against tumors, also inadvertently plays a supportive role in promoting the development and progression of tumors. Hence, two opposing forces ʹhanging in the balanceʹ dictate patientsʹ responses to melanoma: tumor cell biology and the status of the immune system. Recent developments in our understanding of both of these aspects have provided new leads and insights for novel ways to improve vaccine design and add to the melanoma vaccine armory. As the focus of immunotherapy shifts its aim towards the tumor microenvironment, we are now developing the ability to program the immune responses raised by vaccination against melanoma. The aim here is to prevent myeloid and regulatory T‐cell‐mediated immune suppression as well as to counteract tumorderived factors capable of suppressing immune responses. A redirected strategy for vaccine immunotherapy is proposed based on our greater understanding of tumor immunity. Using a combination therapy of immune‐potentiating melanoma vaccines together with adjuvants for overcoming the immunosuppressive forces will allow us to activate protective immunity against melanoma. Other cancer vaccines (i.e. colon or renal) are already offering reasons for hope and expectation that vaccine immunotherapy will also produce successful outcomes for patients with melanoma.
S. Dezfouli, I. Hatzinisiriou and S. Ralph, “Enhancing CTL responses to melanoma cell vaccines in vivo: synergistic increases obtained using IFNgamma primed and IFNbeta treated B7‐1+ B16‐F10 melanoma cells.,” Immunology and cell biology, vol. 81, no. 6, pp. 456‐71, 2003.
Sequentially treating human melanoma cell lines by priming with interferon-gamma before adding interferon-beta was previously found to be the most efficient protocol for producing concurrently increased expression of the three surface antigens B7-1, intercellular adhesion molecule-1 and human histocompatibility leucocyte antigens Class I. The present study describes similar outcomes when the same sequential intercellular adhesion molecule-based protocol is applied to murine B16-F10 melanoma cells as well as preclinical studies using the B16-F10 model as a poorly immunogenic melanoma. Thus, treating B16-F10 cells or a highly expressing B7-1 transfected subline (B16-F10/B7-1 hi) by priming with interferon-gamma for 24 h before adding interferon- for a further 48 h (interferon-gamma 72/beta 48) increased expression of all three surface antigens, particularly major histocompatibility complex class I whose increased expression was sustained for several days. As a whole tumour cell vaccine, interferon-gamma 72/beta 48 treated B16-F10 cells produced greater levels of cytoxic T lymphocyte response compared to vaccines prepared from cells treated with a single type of interferon. Furthermore, B16-F10 cells expressing high levels of B7-1 and treated using the interferon-gamma 72/beta 48 protocol (interferon-gamma 72/beta 48-treated B16-F10/B7-1 hi) produced substantially increased cytoxic T lymphocyte responses with a fivefold greater synergy than the combined results of either interferon treated or B7-1 expressing cells tested individually. The resulting CD8+ cytoxic T lymphocyte showed greater specificity for B16-F10 cells with tenfold higher killing than for syngeneic EL-4 lymphoma cells. Killing proceeded via the perforin-mediated pathway. CTL responses were induced independent of CD4+ T helper cells. The majority of mice receiving interferon-gamma 72/beta 48-treated B16-F10/B7-1 hi vaccine in vivo remained tumour free after challenge with 5 105 live B16-F10 cells expressing intermediate B7-1 levels. The novel strategy described will help enhance vaccine potency when applied clinically to prepare whole cell based cancer vaccine therapies.
S. Punt, VL. Thijssen, J. Vrolijk, CD. de Kroon, A. Gorter, ES. Jordanova, “Galectin-1, -3 and -9 Expression and Clinical Significance in Squamous Cervical Cancer.,” PLoS One, vol. 10, no. 6, e0129119, June 2015.
Galectins are proteins that bind β-galactoside sugars and provide a new type of potential biomarkers and therapeutic targets in cancer. Galectin-1, -3 and -9 have become the focus of different research groups, but their expression and function in cervical cancer is still unclear. The aim of this study was to determine the phenotype of galectin-1, -3 and -9 expressing cells and the association with clinico-pathological parameters in cervical cancer. Galectin expression was scored in tumor cells, tumor epithelium infiltrating immune cells and stromal cells in squamous cervical cancer (n = 160). Correlations with clinico-pathological parameters and survival were studied according to the REMARK recommendations. We additionally investigated whether the galectins were expressed by tumor cells, fibroblasts, macrophages and T cells. Galectin-1 and -9 were both expressed by tumor cells in 11% of samples, while 84% expressed galectin-3. Strong galectin-1 expression by tumor cells was an independent predictor for poor survival (hazard ratio: 8.02, p = 0.001) and correlated with increased tumor invasion (p = 0.032) and receiving post-operative radiotherapy (p = 0.020). Weak and positive tumor cell galectin-3 expression were correlated with increased and decreased tumor invasion, respectively (p = 0.012). Tumor cell expression of galectin-9 showed a trend toward improved survival (p = 0.087). The predominant immune cell type expressing galectin-1, -3 and -9 were CD163+ macrophages. Galectin-1 and -3 were expressed by a minor population of T cells. Galectin-1 was mainly expressed by fibroblasts in the tumor stroma. To conclude, while tumor cell expression of galectin-9 seemed to represent a beneficial response, galectin-1 expression might be used as a marker for a more aggressive anti-cancer treatment.
EM. Yazawa, JE. Geddes-Sweeney, F. Cedeno-Laurent, KC. Walley, SR. Barthel, MJ. Opperman, J. Liang, JY. Lin, T. Schatton, AC. Laga, MC. Mihm, AA. Qureshi, HR. Widlund, GF Murphy, Murphy and C. Dimitroff, “Melanoma Cell Galectin-1 Ligands Functionally Correlate with Malignant Potential.,” Journal of Investigative Dermatology, vol 135, no. 7, pp 1849-1862, 1 July 2015.
Galectin-1 (Gal-1)-binding to Gal-1 ligands on immune and endothelial cells can influence melanoma development through dampening anti-tumor immune responses and promoting angiogenesis. However, whether Gal-1 ligands are functionally expressed on melanoma cells to help control intrinsic malignant features remains poorly understood. Here, we analyzed expression, identity and function of Gal-1 ligands in melanoma progression. Immunofluorescent analysis of benign and malignant human melanocytic neoplasms revealed that Gal-1 ligands were abundant in severely-dysplastic nevi as well as in primary and metastatic melanomas. Biochemical assessments indicated that melanoma cell adhesion molecule (MCAM) was a major Gal-1 ligand on melanoma cells that was largely dependent on its N-glycans. Other melanoma cell Gal-1 ligand activity conferred by O-glycans was negatively regulated by α2,6 sialyltransferase ST6GalNAc2. In Gal-1-deficient mice, MCAM-silenced (MCAMKD) or ST6GalNAc2-overexpressing (ST6O/E) melanoma cells exhibited slower growth rates, underscoring a key role for melanoma cell Gal-1 ligands and host Gal-1 in melanoma growth. Further analysis of MCAMKD or ST6O/E melanoma cells in cell migration assays indicated that Gal-1 ligand-dependent melanoma cell migration was severely inhibited. These findings provide a refined perspective on Gal-1 – melanoma cell Gal-1 ligand interactions as contributors to melanoma malignancy.
L. Astorgues-Xerri, A. Tijeras-Raballand, M. Serova, C. Neuzillet, S. Albert, E. Raymond, S. Faivre, “Unravelling galectin-1 as a novel therapeutic target for cancer.,” Cancer Treatment Reviews, vol. 40, no. 2, pp. 307-19, March 2014.
Galectins belong to a family of carbohydrate-binding proteins with an affinity for β-galactosides. Galectin-1 is differentially expressed by various normal and pathologic tissues and displays a wide range of biological activities. In oncology, galectin-1 plays a pivotal role in tumor growth and in the multistep process of invasion, angiogenesis, and metastasis. Evidence indicates that galectin-1 exerts a variety of functions at different steps of tumor progression. Moreover, it has been demonstrated that galectin-1 cellular localization and galectin-1 binding partners depend on tumor localization and stage. Recently, galectin-1 overexpression has been extensively documented in several tumor types and/or in the stroma of cancer cells. Its expression is thought to reflect tumor aggressiveness in several tumor types. Galectin-1 has been identified as a promising drug target using synthetic and natural inhibitors. Preclinical data suggest that galectin-1 inhibition may lead to direct antiproliferative effects in cancer cells as well as antiangiogenic effects in tumors. We provide an up-to-date overview of available data on the role of galectin-1 in different molecular and biochemical pathways involved in human malignancies. One of the major challenges faced in targeting galectin-1 is the translation of current knowledge into the design and development of effective galectin-1 inhibitors in cancer therapy.
K. Ito, S. Scott, S. Cutler, L. Dong, J. Neuzil, H. Blanchard and S. Ralph, “Thiodigalactoside inhibits murine cancers by concurrently blocking effects of galectin-1 on immune dysregulation, angiogenesis and protection against oxidative stress.,” Angiogenesis, vol. 14, no. 3, pp. 293-307, September 2011.
Cancer cells produce galectin-1 as a tumor promoting protein. Thiodigalactoside (TDG) as a non-metabolised small drug, is shown to suppress tumor growth by inhibiting multiple cancer enhancing activities of galectin-1, including immune cell dysregulation, angiogenesis and protection against oxidative stress. Thus, using B16F10 melanoma and 4T1 orthotopic breast cancer models, intratumoral injection of TDG significantly raised the levels of tumor-infiltrating CD8+ lymphocytes and reduced CD31+ endothelial cell content, reducing tumor growth. TDG treatment of tumors in Balb/c nude mice (defective in T cell immunity) reduced angiogenesis and slowed tumor growth by a third less than in immunocompetent mice. Knocking down galectin-1 expression (G1KD) in both cancer cell types significantly impeded tumor growth and the sensitivity of the G1KD tumors to TDG was severely reduced, highlighting a specific role for galectin-1. Endothelial cells were protected by galectin-1 from oxidative stress-induced apoptosis induced by H2O2, but TDG inhibited this antioxidant protective effect of galectin-1 and reduced tube forming activity in angiogenic assays. We show for the first time that the single agent, TDG, concurrently prevents many tumor promoting effects of galectin-1 on angiogenesis, immune dysregulation and protection against oxidative stress, providing a potent and novel small molecule as an anti-cancer drug.
AH. Ebrahim, Z. Alalawi, L. Miradola, R. Rakhshanda, S. Dahlbeck, D. Nguyen, M. Jenkins, F. Grizzi, E. Cobos, JA. Figueroa, M. Chiriva-Internati, “Galectins in cancer: carcinogenesis, diagnosis and therapy,” Journal of Translational Medicine, vol. 2, no. 9, pp. 88, September 2014.
A major breakthrough in the field of medical oncology has been the discovery of galectins and their role in cancer development, progression and metastasis. In this review article we have condensed the results of a number of studies published over the past decade in an effort to shed some light on the unique role played by the galectin family of proteins in neoplasia, and how this knowledge may alter the approach to cancer diagnosis as well as therapy in the future. In this review we have also emphasized the potential use of galectin inhibitors or modulators in the treatment of cancer and how this novel treatment modality may affect patient outcomes in the future. Based on current pre-clinical models we believe the use of galectin inhibitors/modulators will play a significant role in cancer treatment in the future. Early clinical studies are underway to evaluate the utility of these promising agents in cancer patients.
K. Kluckova, M. Sticha, J. Cerny, T. Mracek, L. Dong, Z. Drahota, E. Gottlieb, J. Neuzil, and J. Rohlena, “Ubiquinone-binding site mutagenesis reveals the role of mitochondrial complex II in cell death initiation.,” Cell Death & Disease, e1749; doi:10.1038/cddis.2015.110, 7 May 2015.
Respiratory complex II (CII, succinate dehydrogenase, SDH) inhibition can induce cell death, but the mechanistic details need clarification. To elucidate the role of reactive oxygen species (ROS) formation upon the ubiquinone-binding (Qp) site blockade, we substituted CII subunit C (SDHC) residues lining the Qp site by site-directed mutagenesis. Cell lines carrying these mutations were characterized on the bases of CII activity and exposed to Qp site inhibitors MitoVES, thenoyltrifluoroacetone (TTFA) and Atpenin A5. We found that I56F and S68A SDHC variants, which support succinate-mediated respiration and maintain low intracellular succinate, were less efficiently inhibited by MitoVES than the wild-type (WT) variant. Importantly, associated ROS generation and cell death induction was also impaired, and cell death in the WT cells was malonate and catalase sensitive. In contrast, the S68A variant was much more susceptible to TTFA inhibition than the I56F variant or the WT CII, which was again reflected by enhanced ROS formation and increased malonate- and catalase-sensitive cell death induction. The R72C variant that accumulates intracellular succinate due to compromised CII activity was resistant to MitoVES and TTFA treatment and did not increase ROS, even though TTFA efficiently generated ROS at low succinate in mitochondria isolated from R72C cells. Similarly, the high-affinity Qp site inhibitor Atpenin A5 rapidly increased intracellular succinate in WT cells but did not induce ROS or cell death, unlike MitoVES and TTFA that upregulated succinate only moderately. These results demonstrate that cell death initiation upon CII inhibition depends on ROS and that the extent of cell death correlates with the potency of inhibition at the Qp site unless intracellular succinate is high. In addition, this validates the Qp site of CII as a target for cell death induction with relevance to cancer therapy.
AS. Tan, JW. Baty, LF. Dong, A. Bezawork-Geleta, B. Endaya, J. Goodwin, M. Bajzikova, J. Kovarova, M. Peterka, B. Yan, EA. Pesdar, M. Sobol, A. Filimonenko, S. Stuart, M. Vondrusova, K. Kluckova, K. Sachaphibulkij, J. Rohlena, P. Hozak, J. Truksa, D. Eccles, LM. Haupt, LR. Griffiths, J. Neuzil, MV. Berridge, ” Mitochondrial genome acquisition restores respiratory function and tumorigenic potential of cancer cells without mitochondrial DNA.,” Cell Metabolism, vol. 21, no. 1, pp. 81-94, 6 January 2015.
We report that tumor cells without mitochondrial DNA (mtDNA) show delayed tumor growth, and that tumor formation is associated with acquisition of mtDNA from host cells. This leads to partial recovery of mitochondrial function in cells derived from primary tumors grown from cells without mtDNA and a shorter lag in tumor growth. Cell lines from circulating tumor cells showed further recovery of mitochondrial respiration and an intermediate lag to tumor growth, while cells from lung metastases exhibited full restoration of respiratory function and no lag in tumor growth. Stepwise assembly of mitochondrial respiratory (super)complexes was correlated with acquisition of respiratory function. Our findings indicate horizontal transfer of mtDNA from host cells in the tumor microenvironment to tumor cells with compromised respiratory function to re-establish respiration and tumor-initiating efficacy. These results suggest pathophysiological processes for overcoming mtDNA damage and support the notion of high plasticity of malignant cells.
B. Yan, M. Stantic, R. Zobalova, A. Bezawork-Geleta, M. Stapelberg, J. Stursa, K. Prokopova, L. Dong, J. Neuzil, “Mitochondrially targeted vitamin E succinate efficiently kills breast tumour-initiating cells in a complex II-dependent manner.,” BMC Cancer. 15:401. doi: 10.1186/s12885-015-1394-7, 13 May 2015.
Accumulating evidence suggests that breast cancer involves tumour-initiating cells (TICs), which play a role in initiation, metastasis, therapeutic resistance and relapse of the disease. Emerging drugs that target TICs are becoming a focus of contemporary research. Mitocans, a group of compounds that induce apoptosis of cancer cells by destabilising their mitochondria, are showing their potential in killing TICs. In this project, we investigated mitochondrially targeted vitamin E succinate (MitoVES), a recently developed mitocan, for its in vitro and in vivo efficacy against TICs. The mammosphere model of breast TICs was established by culturing murine NeuTL and human MCF7 cells as spheres. This model was verified by stem cell marker expression, tumour initiation capacity and chemotherapeutic resistance. Cell susceptibility to MitoVES was assessed and the cell death pathway investigated. In vivo efficacy was studied by grafting NeuTL TICs to form syngeneic tumours. Mammospheres derived from NeuTL and MCF7 breast cancer cells were enriched in the level of stemness, and the sphere cells featured altered mitochondrial function. Sphere cultures were resistant to several established anti-cancer agents while they were susceptible to MitoVES. Killing of mammospheres was suppressed when the mitochondrial complex II, the molecular target of MitoVES, was knocked down. Importantly, MitoVES inhibited progression of syngeneic HER2(high) tumours derived from breast TICs by inducing apoptosis in tumour cells. These results demonstrate that using mammospheres, a plausible model for studying TICs, drugs that target mitochondria efficiently kill breast tumour-initiating cells.
J. Kovarova, M. Bajzikova, M. Vondrusova, J. Stursa, J. Goodwin, M. Nguyen, R. Zobalova, E. Pesdar, J. Truksa, M. Tomasetti, L. Dong and J. Neuzil, “Mitochondrial targeting of α-tocopheryl succinate enhances its anti-mesothelioma efficacy.,” Redox Report, vol. 19, no. 1, pp. 16-25, January 2014.
Malignant mesothelioma (MM) is a fatal neoplastic disease with no therapeutic option. Therefore, the search for novel therapies is of paramount importance. Since mitochondrial targeting of α-tocopheryl succinate (α-TOS) by its tagging with triphenylphosphonium enhances its cytotoxic effects to cancer cells, we tested its effect on MM cells and experimental mesotheliomas. Mitochondrially targeted vitamin E succinate (MitoVES) was more efficient in killing MM cells than α-TOS with IC50 lower by up to two orders of magnitude. Mitochondrial association of MitoVES in MM cells was documented using its fluorescently tagged analogue. MitoVES caused apoptosis in MM cells by mitochondrial destabilization, resulting in the loss of mitochondrial membrane potential, generation of reactive oxygen species, and destabilization of respiratory supercomplexes. The role of the mitochondrial complex II in the activity of MitoVES was confirmed by the finding that MM cells with suppressed succinate quinone reductase were resistant to MitoVES. MitoVES suppressed mesothelioma growth in nude mice with high efficacy. MitoVES is more efficient in killing MM cells and suppressing experimental mesotheliomas compared with the non-targeted α-TOS, giving it a potential clinical benefit.
SJ. Ralph, R. Moreno-Sanchez, J. Neuzil, S. Rodriguez-Enriquez, “Inhibitors of succinate: quinone reductase/Complex II regulate production of mitochondrial reactive oxygen species and protect normal cells from ischemic damage but induce specific cancer cell death,” Pharmaceutical Research, vol. 28, pp. 2695-730, November 2011.
Succinate:quinone reductase (SQR) of Complex II occupies a unique central point in the mitochondrial respiratory system as a major source of electrons driving reactive oxygen species (ROS) production. It is an ideal pharmaceutical target for modulating ROS levels in normal cells to prevent oxidative stress-induced damage or alternatively,increase ROS in cancer cells, inducing cell death.The value of drugs like diazoxide to prevent ROS production,protecting normal cells, whereas vitamin E analogues promote ROS in cancer cells to kill them is highlighted. As pharmaceuticals these agents may prevent degenerative disease and their modes of action are presently being fully explored. The evidence that SDH/Complex II is tightly coupled to the NADH/NAD+ ratio in all cells,impacted by the available supplies of Krebs cycle intermediates as essential NAD-linked substrates, and the NAD+-dependent regulation of SDH/Complex II are reviewed, as are links to the NAD+-dependent dehydrogenases, Complex I and the E3 dihiydrolipoamide dehydrogenase to produce ROS. This review collates and discusses diverse sources of information relating to ROS production in different biological systems, focussing on evidence for SQR as the main source of ROS production in mitochondria, particularly its relevance to protection from oxidative stress and to the mitochondrial-targeted anti cancer drugs (mitocans) as novel cancer therapies [corrected].