The microculture-kinetic (MiCK) assay: the role of a drug-induced apoptosis assay in drug development and clinical care

Soft Tissue Sarcoma Study: Association of Genetic Alterations in the Apoptosis Pathways with Chemoresistance to Doxorubicin

Simple Summary

Genotoxic chemotherapy is the main component of the treatment for advanced soft tissue sarcomas. However, its efficacy is rather low and it is followed by rapid appearance of drug resistance. Our study was directed to the search of molecular drivers of chemoresistance in synovial and undifferentiated pleomorphic sarcomas to genotoxic drugs mostly used for their treatment. Using primary cell cultures obtained from sarcomas after surgery, we estimated their chemoresistance in vitro and performed exome sequencing. We revealed that cancer cells of more than one quarter of patients had molecular alterations preventing apoptosis and observed an association between molecular alterations found and chemoresistance to Doxorubicin, but not to Ifosfamide or Gemcitabine and Docetaxel. Information concerning the peculiar drivers of individual drug resistance could help to improve personalized chemotherapy by withdrawal from an inefficient drug or by targeting the revealed mechanism of chemoresistance.

Abstract

Soft tissue sarcomas (STS) are heterogeneous cancers with more than 100 histological subtypes, different in molecular alterations, which make its personalized therapy very complex. Gold standard of chemotherapy for advanced STS includes combinations of Doxorubicin and Ifosfamide or Gemcitabine and Docetaxel. Chemotherapy is efficient for less than 50% of patients and it is followed by a fast development of drug resistance. Our study was directed to the search of genetic alterations in cancer cells associated with chemoresistance of undifferentiated pleomorphic and synovial sarcomas to the abovementioned genotoxic drugs. We analyzed chemoresistance of cancer cells in vitro using primary STS cultures and performed genetic analysis for the components of apoptotic signaling. In 27% of tumors, we revealed alterations in TP53, ATM, PIK3CB, PIK3R1, NTRK1, and CSF2RB. Cells from STS specimens with found genetic alterations were resistant to Dox, excluding the only one case when TP53 mutation resulted in the substitution Leu344Arg associated with partial oligomerization loss and did not cause total loss of TP53 function. Significant association between alterations in the components of apoptosis signaling and chemoresistance to Dox was found. Our data are important to elaborate further the therapeutic strategy for STS patients with alterations in apoptotic signaling.

Analysis of Multiple Drug Resistance Mechanism in Different Types of Soft Tissue Sarcomas: Assessment of the Expression of ABC-Transporters, MVP, YB-1, and Analysis of Their Correlation with Chemosensitivity of Cancer Cells

Chemotherapy of soft tissue sarcomas (STS) is restricted by low chemosensitivity and multiple drug resistance (MDR). The purpose of our study was the analysis of MDR mechanism in different types of STS. We assessed the expression of ABC-transporters, MVP, YB-1, and analyzed their correlation with chemosensitivity of cancer cells. STS specimens were obtained from 70 patients without metastatic disease (2018–2020). Expression level of MDR-associated genes was estimated by qRT-PCR and cytofluorimetry. Mutations in ABC-transporter genes were captured by exome sequencing. Chemosensitivity (SI) of STS to doxorubicin (Dox), ifosfamide (Ifo), gemcitabine (Gem), and docetaxel (Doc) was analyzed in vitro. We found strong correlation in ABCB1, ABCC1, and ABCG2 expression. We demonstrated strong negative correlations in ABCB1 and ABCG2 expression with SI (Doc) and SI (Doc + Gem), and positive correlation of MVP expression with SI (Doc) and SI (Doc + Gem) in undifferentiated pleomorphic sarcoma. Pgp expression was shown in 5 out of 44 STS samples with prevalence of synovial sarcoma relapses and it is strongly correlated with SI (Gem). Mutations in MDR-associated genes were rarely found. Overall, STS demonstrated high heterogeneity in chemosensitivity that makes reasonable in vitro chemosensitivity testing to improve personalized STS therapy, and classic ABC-transporters are not obviously involved in MDR appearance.

Benefits of functional assays in personalized cancer medicine: more than just a proof-of-concept

As complex and heterogeneous diseases, cancers require a more tailored therapeutic management than most pathologies. Recent advances in anticancer drug development, including the immuno-oncology revolution, have been too often plagued by unsatisfying patient response rates and survivals. In reaction to this, cancer care has fully transitioned to the “personalized medicine” concept. Numerous tools are now available tools to better adapt treatments to the profile of each patient. They encompass a large array of diagnostic assays, based on biomarkers relevant to targetable molecular pathways. As a subfamily of such so-called companion diagnostics, chemosensitivity and resistance assays represent an attractive, yet insufficiently understood, approach to individualize treatments. They rely on the assessment of a composite biomarker, the ex vivo functional response of cancer cells to drugs, to predict a patient's outcome. Systemic treatments, such as chemotherapies, as well as targeted treatments, whose efficacy cannot be fully predicted yet by other diagnostic tests, may be assessed through these means. The results can provide helpful information to assist clinicians in their decision-making process. We explore here the most advanced functional assays across oncology indications, with an emphasis on tests already displaying a convincing clinical demonstration. We then recapitulate the main technical obstacles faced by researchers and clinicians to produce more accurate, and thus more predictive, models and the recent advances that have been developed to circumvent them. Finally, we summarize the regulatory and quality frameworks surrounding functional assays to ensure their safe and performant clinical implementation. Functional assays are valuable in vitro diagnostic tools that already stand beyond the “proof-of-concept” stage. Clinical studies show they have a major role to play by themselves but also in conjunction with molecular diagnostics. They now need a final lift to fully integrate the common armament used against cancers, and thus make their way into the clinical routine.

Exploring the Potential of Drug Response Assays for Precision Medicine in Ovarian Cancer

One of the major challenges in the treatment of cancer are differential responses of patients to existing standard of care anti-cancer drugs. These differential responses may, in part, be due to a diverse range of genomic, epigenomic, proteomic, and metabolic alterations among individuals suffering from the same type of cancer. Precision medicine is an emerging approach in cancer therapeutics that takes into account specific molecular alterations, environmental factors as well as lifestyle of individual patients. This approach allows clinicians and researchers to select or predict treatments that would most likely benefit the patient based on their individual tumor characteristics. One class of precision medicine tools are predictive, in vitro drug-response assays designed to test the sensitivity of patient tumor cells to existing or novel therapies. These assays have the potential to rapidly identify the most effective treatments for cancer patients and thus hold great promise in the field of precision medicine. In this review, we have highlighted several drug-response assays developed in ovarian cancer and discussed the current challenges and future prospects of these assays in the clinical management of this disease.

A retrospective study of the correlation of in vitro chemosensitivity using ATP-TCA with patient clinical outcomes in acute myeloid leukemia

PURPOSE

To evaluate the predictive value of the in vitro chemosensitivity using ATP-TCA method to compare the clinical efficacy of patients with AML.

METHODS

Bone marrow or peripheral blood samples were collected from 65 patients with AML, and the in vitro chemosensitivity of four drugs (cytarabine/idarubicin/decitabine/aclacinomycin) was measured by an ATP-tumor chemosensitivity assay.

RESULTS

Aclacinomycin and cytarabine had the highest chemosensitivity rates (66.7%, 8/12 and 58.5%, 38/65, respectively), while idarubicin and decitabine had rates of 6.5% (3/46) and 0% (0/35), respectively. Complete remission (CR) was achieved in 66.2% (43/65) of patients, and there was a statistically significant correlation between CR and in vitro chemosensitivity for cytarabine (47.7% vs 18.5%, p = 0.002), but not for the anthracyclines (p = 0.950). In addition, three other factors significantly correlated with CR: disease status (p = 0.005), FLT3-ITD/TKD mutation (p = 0.003) and chemotherapy regimens (p = 0.004). Furthermore, multiple logistic regression analysis revealed that the sensitivity of cytarabine was one of the significant risk factors for CR [hazard ratio (HR) = 5.52; 95% confidence interval (CI) = 1.47-20.70; p = 0.011].

CONCLUSIONS

The in vitro chemosensitivity as tested by ATP-TCA demonstrated a significant correlation with CR for chemotherapy and can be a useful tool to optimize personalized treatments for patients with AML.

FOXO3a Reverses the Cisplatin Resistance in Ovarian Cancer

OBJECTIVE

Ovarian cancer is one of the most serious disease in female reproductive system. Platinum is the first-line drug for the treatment of ovarian cancer, while the resistance of platinum drug in clinical hindered the relief ovarian cancer. Our previous study found that decreased FOXO3a might be a poor prognosis in human ovarian cancer. In this research, we study whether FOXO3a was involved in the mechanism of platinum drug resistance.

METHODS

The CCK-8 and FACS analysis were used to monitor the survival of ovarian cancer, and the FOXO3a expression was detected by western-blot.

RESULTS

We found that FOXO3a expression upregulated significantly in A2780 compared with A2780/DDP cells with the treatment of platinum. Moreover, overexpression of FOXO3a in ovarian cancer inversed the platinum resistance in ovarian cancer.

CONCLUSION

These observations reminded that the role of FOXO3a might be one of the critical mechanisms in developing platinum drug resistance in ovarian cancer.

A mechanism for semaphorin-induced apoptosis: DNA damage of endothelial and myogenic cells in primary cultures from skeletal muscle

One hallmark of cancer is its ability to recruit a vascular supply to support rapid growth. Suppression of angiogenesis holds potential as a second-line or adjuvant therapy to stunt cancer growth, progression, metastasis, and post-resection regeneration. To begin to test the hypothesis that semaphorin 3A and 3F together, will induce endothelial cell apoptosis by inducing DNA damage, mixed primary cultures isolated from normal adult mouse skeletal muscle were treated for 48 hr with Sema3A ± Sema3F (100ng/mL). Changes in surviving-cell density, DNA synthesis, DNA repair (gamma-Histone 2AX, γH2AX, an indirect measure for DNA damage), and apoptotic DNA fragmentation (TUNEL staining) were assayed in cultures of CD31+ endothelial and desmin+ muscle cells. Sema3F increased DNA damage-associated DNA repair in both cell types. Co-treatment with Sema3A+3F increased γH2AX staining ~25-fold over control levels, and further increased apoptosis compared to control and Sema3A alone. Results were negated by treatment with neutralizing anti-semaphorin antibodies and are interpreted as suggesting that Sema3A may sensitize endothelial but not muscle cells to Sema3F-induced DNA damage. These preliminary findings on a complex system of interacting cells may contribute to developing applications that could target angiogenic regulatory mechanisms for their therapeutic potential against cancer progression and metastasis.

Evolution of Chemosensitivity and Resistance Assays as Predictors of Clinical Outcomes in Epithelial Ovarian Cancer Patients

Epithelial ovarian cancer (EOC) is responsible for more cancer-related deaths than any other malignancy of the female reproductive system. The standard of care for advanced EOC involves a combination of cytoreductive surgery and platinum-based chemotherapy. Although a majority of patients respond to a platinum-containing regimen, many fail to respond to first-line treatment (platinum-refractory disease) or experience disease progression within 6 months of completing treatment (platinum-resistant disease). Even in patients who initially respond to platinum-based therapy, secondary development of platinum resistance is common. Many chemotherapeutic regimens with comparable efficacy and toxicities are available, leaving the determination of optimal therapy to the physician's discretion. There have been many efforts over the years to develop accurate predictors of outcomes in patients treated with chemotherapy to help inform treatment decisions. Predictive treatment markers are particularly relevant in a disease such as EOC, where a large number of similarly efficacious chemotherapy regimens are available. Chemosensitivity and resistance assays (CSRAs) are attractive approaches to interrogate the efficacy and complex biology of EOC. Some early predictive cellular tests, such as the early clonogenic assays, were limited by technical and logistical issues. Over time, changes in these assays have improved their prognostic and predictive value, but there is still a lack of widespread adoption due to methodological difficulties or limited clinical validation. Herein, we provide an overview of the evolution of CSRAs used to predict outcomes in patients treated with chemotherapy that have been evaluated for use in EOC, with a focus on the latest generation chemoresponse assay.

Bringing 3D tumor models to the clinic - predictive value for personalized medicine

Current decision-guiding algorithms in cancer drug treatment are based on decades of research and numerous clinical trials. For the majority of patients, this data is successfully applied for a systemic disease management. For a number of patients however, treatment stratification according to clinically based risk criteria will not be sufficient. The most effective treatment options are ideally identified prior to the start of clinical drug therapy. This review will discuss the implementation of three-dimensional (3D) cell culture models as a preclinical testing paradigm for the efficacy of clinical cancer treatment. Patient tumor-derived cells in 3D cultures duplicate the individual tumor microenvironment with a minimum of confounding factors. Clinical implementation of such personalized tumor models requires a high quality of methodological and clinical validation comparable to other biomarkers. A non-systematic literature search demonstrated the small number of prospective studies that have been conducted in this area of research. This may explain the current reluctance of many physicians and insurance providers in implementing this type of assay into the clinical diagnostic routine despite potential benefit for patients. Achieving valid and reproducible results with a high level of evidence is central in improving the acceptance of preclinical 3D tumor models.

Microfluidic Biopsy Trapping Device for the Real-Time Monitoring of Tumor Microenvironment

The tumor microenvironment is composed of cellular and stromal components such as tumor cells, mesenchymal cells, immune cells, cancer associated fibroblasts and the supporting extracellular matrix. The tumor microenvironment provides crucial support for growth and progression of tumor cells and affects tumor response to therapeutic interventions. To better understand tumor biology and to develop effective cancer therapeutic agents it is important to develop preclinical platforms that can faithfully recapitulate the tumor microenvironment and the complex interaction between the tumor and its surrounding stromal elements. Drug studies performed in vitro with conventional two-dimensional cancer cell line models do not optimally represent clinical drug response as they lack true tumor heterogeneity and are often performed in static culture conditions lacking stromal tumor components that significantly influence the metabolic activity and proliferation of cells. Recent microfluidic approaches aim to overcome such obstacles with the use of cell lines derived in artificial three-dimensional supportive gels or micro-chambers. However, absence of a true tumor microenvironment and full interstitial flow, leads to less than optimal evaluation of tumor response to drug treatment. Here we report a continuous perfusion microfluidic device coupled with microscopy and image analysis for the assessment of drug effects on intact fresh tumor tissue. We have demonstrated that fine needle aspirate biopsies obtained from patient-derived xenograft models of adenocarcinoma of the lung can successfully be analyzed for their response to ex vivo drug treatment within this biopsy trapping microfluidic device, wherein a protein kinase C inhibitor, staurosporine, was used to assess tumor cell death as a proof of principle. This approach has the potential to study tumor tissue within its intact microenvironment to better understand tumor response to drug treatments and eventually to choose the most effective drug and drug combination for individual patients in a cost effective and timely manner.

A Small Molecule that Induces Intrinsic Pathway Apoptosis with Unparalleled Speed

Apoptosis is generally believed to be a process that requires several hours, in contrast to non-programmed forms of cell death that can occur in minutes. Our findings challenge the time-consuming nature of apoptosis as we describe the discovery and characterization of a small molecule, named Raptinal, which initiates intrinsic pathway caspase-dependent apoptosis within minutes in multiple cell lines. Comparison to a mechanistically diverse panel of apoptotic stimuli reveals that Raptinal-induced apoptosis proceeds with unparalleled speed. The rapid phenotype enabled identification of the critical roles of mitochondrial voltage-dependent anion channel function, mitochondrial membrane potential/coupled respiration, and mitochondrial complex I, III, and IV function for apoptosis induction. Use of Raptinal in whole organisms demonstrates its utility for studying apoptosis in vivo for a variety of applications. Overall, rapid inducers of apoptosis are powerful tools that will be used in a variety of settings to generate further insight into the apoptotic machinery.

Programmed cell death in aging

Programmed cell death (PCD) pathways, including apoptosis and regulated necrosis, are required for normal cell turnover and tissue homeostasis. Mis-regulation of PCD is increasingly implicated in aging and aging-related disease. During aging the cell turnover rate declines for several highly-mitotic tissues. Aging-associated disruptions in systemic and inter-cell signaling combined with cell-autonomous damage and mitochondrial malfunction result in increased PCD in some cell types, and decreased PCD in other cell types. Increased PCD during aging is implicated in immune system decline, skeletal muscle wasting (sarcopenia), loss of cells in the heart, and neurodegenerative disease. In contrast, cancer cells and senescent cells are resistant to PCD, enabling them to increase in abundance during aging. PCD pathways limit life span in fungi, but whether PCD pathways normally limit adult metazoan life span is not yet clear. PCD is regulated by a balance of negative and positive factors, including the mitochondria, which are particularly subject to aging-associated malfunction.

Application of a drug-induced apoptosis assay to identify treatment strategies in recurrent or metastatic breast cancer

Background

A drug-induced apoptosis assay has been developed to determine which chemotherapy drugs or regimens can produce higher cell killing in vitro. This study was done to determine if this assay could be performed in patients with recurrent or metastatic breast cancer patients, to characterize the patterns of drug-induced apoptosis, and to evaluate the clinical utility of the assay. A secondary goal was to correlate assay use with clinical outcomes.

Methods

In a prospective, non-blinded, multi institutional controlled trial, 30 evaluable patients with recurrent or metastatic breast cancer who were treated with chemotherapy had tumor samples submitted for the MiCK drug-induced apoptosis assay. After receiving results within 72 hours after biopsy, physicians could use the test to determine therapy (users), or elect to not use the test (non-users).

Results

The assay was able to characterize drug-induced apoptosis in tumor specimens from breast cancer patients and identified which drugs or combinations gave highest levels of apoptosis. Patterns of drug activity were also analyzed in triple negative breast cancer. Different drugs from a single class of agents often produced significantly different amounts of apoptosis. Physician frequently (73%) used the assay to help select chemotherapy treatments in patients, Patients whose physicians were users had a higher response (CR+PR) rate compared to non-users (38.1% vs 0%, p = 0.04) and a higher disease control (CR+PR+Stable) rate (81% vs 25%, p<0.01). Time to relapse was longer in users 7.4 mo compared to non-users 2.2 mo (p<0.01).

Conclusions

The MiCK assay can be performed in breast cancer specimens, and results are often used by physicians in breast cancer patients with recurrent or metastatic disease. These results from a good laboratory phase II study can be the basis for a future larger prospective multicenter study to more definitively establish the value of the assay.

Trial Registration

Clinicaltrials.gov NCT00901264

Overview of a chemoresponse assay in ovarian cancer

The objective of this review is to summarize recent scientific and medical literature regarding chemoresponse assays or chemotherapy sensitivity and resistance assays (CSRAs), specifically as applied to epithelial ovarian cancer. A total of sixty-seven articles, identified through PubMed using the key words “in vitro chemoresponse assay,” “chemo sensitivity resistance assay,” “ATP,” “HDRA,” “EDR,” “MiCK,” and “ChemoFx,” were reviewed. Recent publications on marker validation, including relevant clinical trial designs, were also included. Recent CSRA research and clinical studies are outlined in this review. Published findings demonstrate benefits regarding patient outcome with respect to recent CSRAs. Specifically, analytical and clinical validations, as well as clinical utility and economic benefit, of the most common clinically used CSRA in the United States support its use to aid in making effective, individualized clinical treatment selections for patients with ovarian cancer.

Molecular profiling and commercial predication assays in ovarian cancer: still not ready for prime time?

Short of early detection to allow curative primary intervention, the other major barrier to further success in treatment of ovarian cancers is matching the best treatment to the proper ovarian cancer type and to the individual patient. There are several decades of experience applying in vitro chemoresponse testing for solid tumors including ovarian cancer. This concept, first described in 1979, has yet to receive level one evidence supporting its application, despite the testing of numerous assays commercially as well as in academic centers and its use for tens of thousands of patients at a significant cost. The approach-rather than undergoing rigorous scientific examination-is now being muddied by the development of commercial molecular profiling assays from which treatment suggestions are provided. Molecular profiling as a research tool has added value to our understanding and treatment of patients with ovarian cancer. Morphologic and histochemical characterizations coupled now with increasing knowledge of ovarian cancer type-specific molecular patterns is improving our ability to properly diagnosis ovarian cancer type and thus guide therapy. With the exception of the role of germ-line and possibly somatic BRCA1 and BRCA2 mutations and their true predictiveness for probable response to poly(ADP-ribose) polymerase inhibition, molecular typing and profiling has yet to identify druggable molecular targets in ovarian cancer. Its use should be continued as a research and learning tool, and its results should be subjected to clinical trial validation. For very different reasons, neither chemoresponse assays nor molecular profiling are ready for prime time, yet.