Tumors are not merely cancerous cells that undergo mindless proliferation. Rather, they are highly organized and interconnected organ systems. Tumor cells reside in complex microenvironments in which ...they are subjected to a variety of physical and chemical stimuli that influence cell behavior and ultimately the progression and maintenance of the tumor. As cancer bioengineers, it is our responsibility to create physiologic models that enable accurate understanding of the multi-dimensional structure, organization, and complex relationships in diverse tumor microenvironments. Such models can greatly expedite clinical discovery and translation by closely replicating the physiological conditions while maintaining high tunability and control of extrinsic factors. In this review, we discuss the current models that target key aspects of the tumor microenvironment and their role in cancer progression. In order to address sources of experimental variation and model limitations, we also make recommendations for methods to improve overall physiologic reproducibility, experimental repeatability, and rigor within the field. Improvements can be made through an enhanced emphasis on mathematical modeling, standardized in vitro model characterization, transparent reporting of methodologies, and designing experiments with physiological metrics. Taken together these considerations will enhance the relevance of in vitro tumor models, biological understanding, and accelerate treatment exploration ultimately leading to improved clinical outcomes. Moreover, the development of robust, user-friendly models that integrate important stimuli will allow for the in-depth study of tumors as they undergo progression from non-transformed primary cells to metastatic disease and facilitate translation to a wide variety of biological and clinical studies.
Chemoresistant ovarian cancers grow in suspension within the ascites fluid. To screen the effect of chemotherapeutics and biologics on resistant ovarian cancers with a personalized basis, we ...developed a 3D hanging drop spheroid platform.
We initiated spheroids with primary aldehyde dehydrogenase-positive (ALDH
) CD133
ovarian cancer stem cells (OvCSC) from different patient samples and demonstrated that stem cell progeny from harvested spheroids was similar to the primary tumor. OvCSC spheroids were utilized to initiate tumors in immunodeficient mice. Drug responses to cisplatin and ALDH-targeting compound or JAK2 inhibitor determined whether the OvCSC population within the spheroids could be targeted. Cells that escaped therapy were isolated and used to initiate new spheroids and model tumor reemergence in a personalized manner.
OvCSC spheroids from different patients exhibited varying and personalized responses to chemotherapeutics. Xenografts were established from OvCSC spheroids, even with a single spheroid. Distinct responses to therapy were observed in distinct primary tumor xenografts similar to those observed in spheroids. Spheroids resistant to cisplatin/ALDH inhibitor therapy had persistent, albeit lower ALDH expression and complete loss of CD133 expression, whereas those resistant to cisplatin/JAK2 inhibitor therapy were enriched for ALDH
cells.
Our 3D hanging drop suspension platform can be used to propagate primary OvCSCs that represent individual patient tumors effectively by differentiating
and initiating tumors in mice. Therefore, our platform can be used to study cancer stem cell biology and model tumor reemergence to identify new targeted therapeutics from an effective personalized medicine standpoint.
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Ovarian cancer is an extremely lethal gynecologic disease; with the high-grade serous subtype predominantly associated with poor survival rates. Lack of early diagnostic biomarkers and prevalence of ...post-treatment recurrence, present substantial challenges in treating ovarian cancers. These cancers are also characterized by a high degree of heterogeneity and protracted metastasis, further complicating treatment. Within the ovarian tumor microenvironment, cancer stem-like cells and mechanical stimuli are two underappreciated key elements that play a crucial role in facilitating these outcomes. In this review article, we highlight their roles in modulating ovarian cancer metastasis. Specifically, we outline the clinical relevance of cancer stem-like cells, and challenges associated with their identification and characterization and summarize the ways in which they modulate ovarian cancer metastasis. Further, we review the mechanical cues in the ovarian tumor microenvironment, including, tension, shear, compression and matrix stiffness, that influence (cancer stem-like cells and) metastasis in ovarian cancers. Lastly, we outline the challenges associated with probing these important modulators of ovarian cancer metastasis and provide suggestions for incorporating these cues in basic biology and translational research focused on metastasis. We conclude that future studies on ovarian cancer metastasis will benefit from the careful consideration of mechanical stimuli and cancer stem cells, ultimately allowing for the development of more effective therapies.
A laser-based hydrogel degradation technique is developed that allows for local control over hydrogel porosity, fabrication of 3D vascular-derived, biomimetic, hydrogel-embedded microfluidic ...networks, and generation of two intertwining, yet independent, microfluidic networks in a single construct.
Intractable human diseases such as cancers, are context dependent, unique to both the individual patient and to the specific tumor microenvironment. However, conventional cancer treatments are often ...nonspecific, targeting global similarities rather than unique drivers. This limits treatment efficacy across heterogeneous patient populations and even at different tumor locations within the same patient. Ultimately, this poor efficacy can lead to adverse clinical outcomes and the development of treatment-resistant relapse. To prevent this and improve outcomes, it is necessary to be selective when choosing a patient's optimal adjuvant treatment. In this review, we posit the use of personalized, tumor-specific models (TSM) as tools to achieve this remarkable feat. First, using ovarian cancer as a model disease, we outline the heterogeneity and complexity of both the cellular and extracellular components in the tumor microenvironment. Then we examine the advantages and disadvantages of contemporary cancer models and the rationale for personalized TSM. We discuss how to generate precision 3D models through careful and detailed analysis of patient biopsies. Finally, we provide clinically relevant applications of these versatile personalized cancer models to highlight their potential impact. These models are ideal for a myriad of fundamental cancer biology and translational studies. Importantly, these approaches can be extended to other carcinomas, facilitating the discovery of new therapeutics that more effectively target the unique aspects of each individual patient's TME.
In this article, we have presented the case for the application of biomaterials in developing personalized models of complex diseases such as cancers. TSM could bring about breakthroughs in the promise of precision medicine. The critical components of the diverse tumor microenvironments, that lead to treatment failures, include cellular- and extracellular matrix- heterogeneity, and biophysical signals to the cells. Therefore, we have described these dynamic components of the tumor microenvironments, and have highlighted how contemporary biomaterials can be utilized to create personalized in vitro models of cancers. We have also described the application of the TSM to predict the dynamic patterns of disease progression, and predict effective therapies that can produce durable responses, limit relapses, and treat any minimal residual disease.
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In this protocol, we outline the procedure for generation of tumor spheroids within 384-well hanging droplets to allow for high-throughput screening of anti-cancer therapeutics in a physiologically ...representative microenvironment. We outline the formation of patient derived cancer stem cell spheroids, as well as, the manipulation of these spheroids for thorough analysis following drug treatment. Specifically, we describe collection of spheroid morphology, proliferation, viability, drug toxicity, cell phenotype and cell localization data. This protocol focuses heavily on analysis techniques that are easily implemented using the 384-well hanging drop platform, making it ideal for high throughput drug screening. While we emphasize the importance of this model in ovarian cancer studies and cancer stem cell research, the 384-well platform is amenable to research of other cancer types and disease models, extending the utility of the platform to many fields. By improving the speed of personalized drug screening and the quality of screening results through easily implemented physiologically representative 3D cultures, this platform is predicted to aid in the development of new therapeutics and patient-specific treatment strategies, and thus have wide-reaching clinical impact.
Intractable human diseases such as cancers, are context dependent, unique to both the individual patient and to the specific tumor microenvironment. However, conventional cancer treatments are often ...nonspecific, targeting global similarities rather than unique drivers. This limits treatment efficacy across heterogeneous patient populations and even at different tumor locations within the same patient. Ultimately, this poor efficacy can lead to poor clinical outcomes and the development of treatment-resistant relapse. To prevent this and improve outcomes, it is necessary to be selective when choosing a patient’s optimal adjuvant treatment. In this review, we posit the use of personalized, tumor-specific disease models (TSM) as tools to achieve this remarkable feat. First, using ovarian cancer as a model disease, we outline the heterogeneity and complexity of both the cellular and extracellular components in the tumor microenvironment. Then we examine the advantages and disadvantages of contemporary cancer models and the rationale for personalized TSM. We discuss how to generate TSM through careful and detailed analysis of patient biopsies with contemporary analysis techniques and utilizing the resultant data to construct precision 3D models
in vitro
. Finally, we provide clinically relevant applications of these versatile personalized cancer models to highlight their potential impact. These models have utility towards a myriad of fundamental cancer biology and translational studies. Importantly, these approaches can be extended to other carcinomas, facilitating the discovery of new therapeutics that more effectively target the unique aspects of each individual patient’s TME.
The extent of lymph node dissection (LND) in bladder cancer (BCa) patients at the time of radical cystectomy may affect oncologic outcome.
To evaluate whether extended versus limited LND prolongs ...recurrence-free survival (RFS).
Prospective, multicenter, phase-III trial patients with locally resectable T1G3 or muscle-invasive urothelial BCa (T2-T4aM0).
Randomization to limited (obturator, and internal and external iliac nodes) versus extended LND (in addition, deep obturator, common iliac, presacral, paracaval, interaortocaval, and para-aortal nodes up to the inferior mesenteric artery).
The primary endpoint was RFS. Secondary endpoints included cancer-specific survival (CSS), overall survival (OS), and complications. The trial was designed to show 15% advantage of 5-yr RFS by extended LND.
In total, 401 patients were randomized from February 2006 to August 2010 (203 limited, 198 extended). The median number of dissected nodes was 19 in the limited and 31 in the extended arm. Extended LND failed to show superiority over limited LND with regard to RFS (5-yr RFS 65% vs 59%; hazard ratio HR=0.84 95% confidence interval 0.58–1.22; p=0.36), CSS (5-yr CSS 76% vs 65%; HR=0.70; p=0.10), and OS (5-yr OS 59% vs 50%; HR=0.78; p=0.12). Clavien grade ≥3 lymphoceles were more frequently reported in the extended LND group within 90d after surgery. Inclusion of T1G3 tumors may have contributed to the negative study result.
Extended LND failed to show a significant advantage over limited LND in RFS, CSS, and OS. A larger trial is required to determine whether extended compared with limited LND leads to a small, but clinically relevant, survival difference (ClinicalTrials.gov NCT01215071).
In this study, we investigated the outcome in bladder cancer patients undergoing cystectomy based on the anatomic extent of lymph node resection. We found that extended removal of lymph nodes did not reduce the rate of tumor recurrence in the expected range.
In this randomized phase-III trial, extended lymph node dissection (LND) failed to show a statistically significant therapeutic advantage over limited LND in bladder cancer patients undergoing radical cystectomy. The benefit from extended LND in the primary endpoint recurrence-free survival was smaller than expected.
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