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Journal ArticleDOI

Targeting hypoxia in cancer therapy

01 Jun 2011-Nature Reviews Cancer (Nature Publishing Group)-Vol. 11, Iss: 6, pp 393-410
TL;DR: The two main approaches, namely bioreductive prodrugs and inhibitors of molecular targets upon which hypoxic cell survival depends are reviewed, and the particular challenges and opportunities these overlapping strategies present are addressed.
Abstract: Hypoxia is a feature of most tumours, albeit with variable incidence and severity within a given patient population. It is a negative prognostic and predictive factor owing to its multiple contributions to chemoresistance, radioresistance, angiogenesis, vasculogenesis, invasiveness, metastasis, resistance to cell death, altered metabolism and genomic instability. Given its central role in tumour progression and resistance to therapy, tumour hypoxia might well be considered the best validated target that has yet to be exploited in oncology. However, despite an explosion of information on hypoxia, there are still major questions to be addressed if the long-standing goal of exploiting tumour hypoxia is to be realized. Here, we review the two main approaches, namely bioreductive prodrugs and inhibitors of molecular targets upon which hypoxic cell survival depends. We address the particular challenges and opportunities these overlapping strategies present, and discuss the central importance of emerging diagnostic tools for patient stratification in targeting hypoxia.
Citations
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Journal ArticleDOI
TL;DR: The current status and possible opportunities for ROS generation for cancer therapy are summarized and it is hoped this review will spur pre-clinical research and clinical practice for ROS-mediated tumour treatments.
Abstract: The reactive oxygen species (ROS)-mediated mechanism is the major cause underlying the efficacy of photodynamic therapy (PDT). The PDT procedure is based on the cascade of synergistic effects between light, a photosensitizer (PS) and oxygen, which greatly favors the spatiotemporal control of the treatment. This procedure has also evoked several unresolved challenges at different levels including (i) the limited penetration depth of light, which restricts traditional PDT to superficial tumours; (ii) oxygen reliance does not allow PDT treatment of hypoxic tumours; (iii) light can complicate the phototherapeutic outcomes because of the concurrent heat generation; (iv) specific delivery of PSs to sub-cellular organelles for exerting effective toxicity remains an issue; and (v) side effects from undesirable white-light activation and self-catalysation of traditional PSs. Recent advances in nanotechnology and nanomedicine have provided new opportunities to develop ROS-generating systems through photodynamic or non-photodynamic procedures while tackling the challenges of the current PDT approaches. In this review, we summarize the current status and discuss the possible opportunities for ROS generation for cancer therapy. We hope this review will spur pre-clinical research and clinical practice for ROS-mediated tumour treatments.

1,305 citations

Journal ArticleDOI
TL;DR: In this article, the intrinsic biochemical properties of reactive oxygen species (ROS) underlie the mechanisms that regulate various physiological functions of living organisms, and they play an essential role in regulating various physiological function.
Abstract: Reactive oxygen species (ROS) play an essential role in regulating various physiological functions of living organisms. The intrinsic biochemical properties of ROS, which underlie the mechanisms ne...

1,260 citations

Journal ArticleDOI
11 Dec 2015-Hypoxia
TL;DR: Better understanding of the role of hypoxia in cancer progression will open new windows for the discovery of new therapeutics targeting hypoxic tumor cells and hypoxic microenvironment.
Abstract: Hypoxia is a non-physiological level of oxygen tension, a phenomenon common in a majority of malignant tumors. Tumor-hypoxia leads to advanced but dysfunctional vascularization and acquisition of epithelial-to-mesenchymal transition phenotype resulting in cell mobility and metastasis. Hypoxia alters cancer cell metabolism and contributes to therapy resistance by inducing cell quiescence. Hypoxia stimulates a complex cell signaling network in cancer cells, including the HIF, PI3K, MAPK, and NFĸB pathways, which interact with each other causing positive and negative feedback loops and enhancing or diminishing hypoxic effects. This review provides background knowledge on the role of tumor hypoxia and the role of the HIF cell signaling involved in tumor blood vessel formation, metastasis, and development of the resistance to therapy. Better understanding of the role of hypoxia in cancer progression will open new windows for the discovery of new therapeutics targeting hypoxic tumor cells and hypoxic microenvironment.

1,231 citations


Cites background from "Targeting hypoxia in cancer therapy..."

  • ...Radiation and drug resistance Resistance of cancer cells to treatment-induced apoptosis is one of the biggest obstacles in cancer therapy.(92) A vast number of cancer patients relapse and suffer from recurring tumors as a result of micro-residual disease, the resistant subpopulation of cancer cells, leading to local recurrence and/or metastasis....

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Journal ArticleDOI
TL;DR: In this review, state-of-the-art studies concerning recent advances in nanotechnology-mediated multimodal synergistic therapy will be systematically discussed, with an emphasis on the construction of multifunctional nanomaterials for realizing bimodal and trimodal synergy therapy.
Abstract: The complexity, diversity, and heterogeneity of tumors seriously undermine the therapeutic potential of treatment. Therefore, the current trend in clinical research has gradually shifted from a focus on monotherapy to combination therapy for enhanced treatment efficacy. More importantly, the cooperative enhancement interactions between several types of monotherapy contribute to the naissance of multimodal synergistic therapy, which results in remarkable superadditive (namely “1 + 1 > 2”) effects, stronger than any single therapy or their theoretical combination. In this review, state-of-the-art studies concerning recent advances in nanotechnology-mediated multimodal synergistic therapy will be systematically discussed, with an emphasis on the construction of multifunctional nanomaterials for realizing bimodal and trimodal synergistic therapy as well as the intensive exploration of the underlying synergistic mechanisms for explaining the significant improvements in synergistic therapeutic outcome. Furtherm...

1,220 citations

Journal ArticleDOI
TL;DR: In this paper, the authors summarize lessons learned from preclinical and clinical studies over the past decade and propose strategies for improving antiangiogenic therapy outcomes for malignant and nonmalignant diseases.

1,093 citations


Cites background from "Targeting hypoxia in cancer therapy..."

  • ...Palazón et al., 2012; Semenza, 2014; Wilson and Hay, 2011)....

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  • ...…to radiotherapy, chemotherapy, and immunotherapy (e.g., fewer oxygen radicals and cell cycle arrest) (Huang et al., 2013; Neri and Supuran, 2011; Wilson and Hay, 2011); tumor growth and genomic instability and expression of growth factors (e.g., IGF1 and TGF-a), oncogenes, and tumor…...

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  • ...In addition to protection from the immune system, hypoxia may select for more malignant cells because cells that respond to physiological cues normally undergo apoptosis under hypoxic conditions (Wilson and Hay, 2011)....

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  • ...Collectively, these observations may explain why intratumoral hypoxia correlates with a poor prognosis in many human cancers (Wilson and Hay, 2011)....

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  • ...Hypoxia also provides a niche for so-called cancer stem cells and facilitates inflammation while also conferring resistance to radiation and many widely used therapeutic agents (Wilson and Hay, 2011)....

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References
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Journal ArticleDOI
TL;DR: Hypoxia-inducible factor 1 (HIF-1) activates the transcription of genes that are involved in crucial aspects of cancer biology, including angiogenesis, cell survival, glucose metabolism and invasion.
Abstract: Hypoxia-inducible factor 1 (HIF-1) activates the transcription of genes that are involved in crucial aspects of cancer biology, including angiogenesis, cell survival, glucose metabolism and invasion. Intratumoral hypoxia and genetic alterations can lead to HIF-1alpha overexpression, which has been associated with increased patient mortality in several cancer types. In preclinical studies, inhibition of HIF-1 activity has marked effects on tumour growth. Efforts are underway to identify inhibitors of HIF-1 and to test their efficacy as anticancer therapeutics.

6,024 citations

Journal ArticleDOI
07 Jan 2005-Science
TL;DR: Emerging evidence supporting an alternative hypothesis is reviewed—that certain antiangiogenic agents can also transiently “normalize” the abnormal structure and function of tumor vasculature to make it more efficient for oxygen and drug delivery.
Abstract: Solid tumors require blood vessels for growth, and many new cancer therapies are directed against the tumor vasculature. The widely held view is that these antiangiogenic therapies should destroy the tumor vasculature, thereby depriving the tumor of oxygen and nutrients. Here, I review emerging evidence supporting an alternative hypothesis-that certain antiangiogenic agents can also transiently "normalize" the abnormal structure and function of tumor vasculature to make it more efficient for oxygen and drug delivery. Drugs that induce vascular normalization can alleviate hypoxia and increase the efficacy of conventional therapies if both are carefully scheduled. A better understanding of the molecular and cellular underpinnings of vascular normalization may ultimately lead to more effective therapies not only for cancer but also for diseases with abnormal vasculature, as well as regenerative medicine, in which the goal is to create and maintain a functionally normal vasculature.

4,952 citations

Journal ArticleDOI
TL;DR: Interest in the topic of tumour metabolism has waxed and waned over the past century, but it has become clear that many of the signalling pathways that are affected by genetic mutations and the tumour microenvironment have a profound effect on core metabolism, making this topic once again one of the most intense areas of research in cancer biology.
Abstract: Interest in the topic of tumour metabolism has waxed and waned over the past century of cancer research. The early observations of Warburg and his contemporaries established that there are fundamental differences in the central metabolic pathways operating in malignant tissue. However, the initial hypotheses that were based on these observations proved inadequate to explain tumorigenesis, and the oncogene revolution pushed tumour metabolism to the margins of cancer research. In recent years, interest has been renewed as it has become clear that many of the signalling pathways that are affected by genetic mutations and the tumour microenvironment have a profound effect on core metabolism, making this topic once again one of the most intense areas of research in cancer biology.

4,169 citations

Journal ArticleDOI
TL;DR: Advances in this direction are essential for identifying new disease genes, for uncovering the biological significance of disease-associated mutations identified by genome-wide association studies and full-genome sequencing, and for identifying drug targets and biomarkers for complex diseases.
Abstract: Given the functional interdependencies between the molecular components in a human cell, a disease is rarely a consequence of an abnormality in a single gene, but reflects the perturbations of the complex intracellular and intercellular network that links tissue and organ systems. The emerging tools of network medicine offer a platform to explore systematically not only the molecular complexity of a particular disease, leading to the identification of disease modules and pathways, but also the molecular relationships among apparently distinct (patho)phenotypes. Advances in this direction are essential for identifying new disease genes, for uncovering the biological significance of disease-associated mutations identified by genome-wide association studies and full-genome sequencing, and for identifying drug targets and biomarkers for complex diseases.

3,978 citations

Journal ArticleDOI
TL;DR: The evidence that indicates that the distribution of many anticancer drugs in tumours is incomplete is summarized, and strategies that might be used either to improve drug penetration through tumour tissue or to select compounds based on their abilities to penetrate tissue are suggested, thereby increasing the therapeutic index.
Abstract: To be most effective anticancer drugs must penetrate tissue efficiently, reaching all the cancer cells that comprise the target population in a concentration sufficient to exert a therapeutic effect. Most research into the resistance of cancers to chemotherapy has concentrated on molecular mechanisms of resistance, whereas the role of limited drug distribution within tumours has been neglected. We summarize the evidence that indicates that the distribution of many anticancer drugs in tumour tissue is incomplete, and we suggest strategies that might be used either to improve drug penetration through tumour tissue or to select compounds based on their abilities to penetrate tissue, thereby increasing the therapeutic index.

2,411 citations