Modification of tumor cell exosome content by transfection with wt-p53 and microRNA-125b expressing plasmid DNA and its effect on macrophage polarization

Exosomes are responsible for intercellular communication between tumor cells and others in the tumor microenvironment. These microvesicles promote oncogensis and can support towards metastasis by promoting a pro-tumorogenic environment. Modifying the exosomal content and exosome delivery are emerging novel cancer therapies. However, the clinical translation is limited due to feasibility of isolating and delivery of treated exosomes as well as an associated immune response in patients. In this study, we provide proof-of-concept for a novel treatment approach for manipulating exosomal content by genetic transfection of tumor cells using dual-targeted hyaluronic acid-based nanoparticles. Following transfection with plasmid DNA encoding for wild-type p53 (wt-p53) and microRNA-125b (miR-125b), we evaluate the transgene expression in the SK-LU-1 cells and in the secreted exosomes. Furthermore, along with modulation of wt-p53 and miR-125b expression, we also show that the exosomes (i.e., wt-p53/exo, miR-125b/exo and combination/exo) have a reprogramed global miRNA profile. The miRNAs in the exosomes were mainly related to the activation of genes associated with apoptosis as well as p53 signaling. More importantly, these altered miRNA levels in the exosomes could mediate macrophage repolarization towards a more pro-inflammatory/antitumor M1 phenotype. However, further studies, especially in vivo studies, are warranted to assess the direct influence of such macrophage reprogramming on cancer cells and oncogenesis post-treatment. The current study provides a novel platform enabling the development of therapeutic strategies affecting not only the cancer cells but also the tumor microenvironment by utilizing the 'bystander effect' through genetic transfer with secreted exosomes. Such modification could also support antitumor environment leading to decreased oncogenesis.

Abstract P2-02-07: Collection, high-resolution imaging, and single cell isolation of circulating tumor cells from patient derived xenograft models using the AccuCyte® – CyteFinder® system

Background: Patient-derived xenograft (PDX) models of human tumors offer many advantages over traditional cell line xenograft models and other mouse models of cancer. A PDX model may be used to randomize a given patient's tumor to multiple treatment regimens in order to predict treatment responses. When PDX models are grouped, they represent a clinical trial "cohort" for testing new therapies and identifying biomarkers of response. One such biomarker is circulating tumor cells (CTCs), which provide a window of the metastatic process. CTCs have been reported in several PDX models, further supporting their clinical relevance. Thus, PDX models may also be used to study the utility of CTC analysis to inform treatment decisions. However, most current CTC technologies intended for use with human samples cannot be used with the small blood volume from mice. The objective of our study was to adapt the AccuCyte® – CyteFinder® (AC-CF) system to detect CTCs from low volumes of mouse blood, and apply this method for the analysis of CTCs in a PDX model, including individual cell retrieval for molecular analysis. Methods: The AC-CF PDX process was modified to include a red blood cell lysis step instead of the density-based separation for the removal of red blood cells. The isolated cells were spread onto microscope slides using a stabilization solution, stained by multi-color immunofluorescence, and visualized by the CF high-resolution multi-channel fluorescence scanner. Automated image analysis identified CTCs, which was followed by single cell retrieval. For optimization of the assay, BT474 breast cancer cells were spiked into blood from a tumor-free control mouse ( approx. 500 cells in 250 µl). Slides with BT474 cells were used to test sensitivity by using antibodies against human cytokeratins (pan-CK), epithelial cell adhesion molecule (EpCAM), and erbB family growth factor receptors (EGFR and HER2) to detect the spiked-in cells. Assay specificity was tested by using antibodies specific for the mouse isoform of CD45. The antibody panel was tested on blood samples from 6 mice carrying small (300-400 mm3) tumors of the breast cancer PDX model (BCM-4888) previously published to have CTCs. Results: BT474 were identified by their large nuclei, positive staining with human specific antibodies against pan-CK, EpCAM, and EGFR/HER2 markers, and negative staining for mouse CD45. BT474 were detected in approximately the same amount as were spiked in. CTCs were identified in the blood of all 6 PDX mice tested. We found 1-6 CTCs per 330 µl of blood, and clusters of CTCs were also identified in 4 mice. Overall, these findings agree with published data on this PDX model. Single CTCs will be isolated using the CytePicker® retrieval module for single cell sequencing to confirm the human origin of these cells. These results along with ongoing work on additional PDX models will be presented at the meeting. Conclusion: The modified AC-CF process is a simple and sensitive method of analyzing small volumes of blood for CTC detection and isolation, features that are critical for the longitudinal analysis of CTCs in PDX models of cancer.

Citation Format: Ramirez AB, Sahay D, Lewis MT, Schiff R, Stilwell JL, Trivedi M, Kaldjian EP. Collection, high-resolution imaging, and single cell isolation of circulating tumor cells from patient derived xenograft models using the AccuCyte® – CyteFinder® system. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-02-07.

Pattern recognition analysis of anterior cingulate cortex blood flow to classify depression polarity

Differentiating bipolar from recurrent unipolar depression is a major clinical challenge. In 18 healthy females and 36 females in a depressive episode--18 with bipolar disorder type I, 18 with recurrent unipolar depression--we applied pattern recognition analysis using subdivisions of anterior cingulate cortex (ACC) blood flow at rest, measured with arterial spin labelling. Subgenual ACC blood flow classified unipolar v. bipolar depression with 81% accuracy (83% sensitivity, 78% specificity).

The spectrum of glomerular diseases in a single center: A clinicopathological correlation

We report the spectrum of biopsy-proven glomerular disease (GD) in a single center in Eastern India. Medical records of 666 patients with biopsy-proven GD over a period of 2 years from July 2010 to July 2012 were retrospectively analyzed. The clinical, laboratory, and histological data were recorded. All biopsy specimens were examined by the same pathologist with light and immunofluorescence microscopy. Electron microscopic analysis was performed only in selected cases. Histologic spectrum of various GDs was studied along with its correlation with the clinical and laboratory parameters. The clinical diagnosis was nephrotic syndrome (NS) in 410 (61.56%), rapidly progressive renal failure/glomerulonephritis in 130 (19.52%), subnephrotic proteinuria/asymtomatic urinary abnormalities in 52 (7.81%), acute kidney injury/acute nephritic syndrome in 40 (6.01%), and macroscopic hematuria in 4 (0.6%) patients. Male: Female ratio was 1.05; 27.92% (n = 186) were < 18 years, 68.47% (n = 456) were 18–59 years, and 3.6% (n = 24) were ≥ 60 years of age. The most common GD was minimal change disease (MCD) (20.12%, n = 134); others were focal segmental glomerulosclerosis (FSGS) (18.02%, n = 15.32%), lupus nephritis (LN) (15.32%, n = 102), membranous nephropathy (MN) (12.01%, n = 80), and IgA nephropathy (IgAN) (8.11%, n = 54). Primary GD was present in 79.13% (n = 527) and common histologies were MCD (25.42%), FSGS (22.58%), MN (14.42%), and IgAN (10.25%). Secondary GD was present in 20.87% (n = 139), with the most common being LN (73.38%, n = 102). Among the NS (n = 410), the most common GD was MCD (31.46%), followed by FSGS (25.6%), MN (15.58%), LN (7.8%), IgAN (6.09%), and membranoproliferative glomerulonephritis (4.88%). FSGS was the most common primary GD in adults, MCD in children, and MN in the elderly patients. The spectrum of GD varies according to the area of study and changes over time. A biopsy registry is needed for documenting this variation.

Is unrecognized bipolar disorder a frequent contributor to apparent treatment resistant depression?

BACKGROUND

There is widespread clinical belief that unrecognized bipolar disorder (BD) is a frequent contributor to apparent treatment resistant depression (TRD). This review attempts to assess the degree to which prevailing empirical data supports that view.

METHODS

All English-language articles published between January 1998 and January 2008 that focused on adults with major depressive disorder (MDD) and BD bearing on the question "Is unrecognized BD a frequent contributor to apparent TRD in patients initially diagnosed with MDD?" were reviewed.

RESULTS

196 articles were reviewed; the preponderance of the data suggested: 1) TRD populations demonstrate high rates of hidden bipolar disorder, 2) there is not sufficient evidence to unequivocally support or reject the hypothesis that patients who relapse despite continued antidepressant treatment are likely to have bipolar spectrum disorder, 3) patients initially diagnosed with MDD do not demonstrate high rates of switching to mania or hypomania when treated with antidepressants and 4) in patients diagnosed with BD, antidepressants are not robustly effective and are poorly tolerated.

LIMITATIONS

The main limitation of this review is that none of the individual studies were designed to test our primary hypothesis.

CONCLUSIONS

This review provides at least moderate support to the hypothesis that BD is a contributor to apparent TRD. Thus, clinicians treating MDD are urged to search for "soft" signs of bipolarity and to be prepared to alter diagnosis and treatment strategies accordingly.

Preadult onset vs. adult onset of major depressive disorder: a replication study

OBJECTIVE

In the first 1500 participants with major depressive disorder (MDD) that entered the sequenced treatment alternatives to relieve depression (STAR*D) study, those with preadult onset MDD were more likely to be women and to have a more chronic, severe and disabling form of depression than those with adult onset MDD. This study seeks to replicate these findings.

METHOD

The second wave of STAR*D enrollees included 2541 out-patients with MDD, divided into preadult (before age 18) and adult (age 18 or later) onset groups.

RESULTS

Participants with a preadult onset of MDD (38%) were younger, ill for longer and more likely to be women than those with adult onset MDD (62%). After adjusting for age, duration of illness and gender, participants with preadult onset MDD also had higher rates of family history of depression, more past suicide attempts, and lower rates of obsessive compulsive and panic disorder.

CONCLUSION

Preadult onset MDD may be associated with a more familial form of depression with more suicidality than adult onset MDD.

Automatic segmentation of pancreatic images using ISODATA alorithm

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Background: Pancreatic cancer is the second most common gastrointestinal malignancy in the United States, where it ranks 4th among all deaths caused by cancers. Early detection of pancreatic cancer remains a challange. Methods: MR images with different T1 and T2 weighting from the anatomical regions with the same imaging parameters were obtained. ISODATA segmentation algorithm, a multivariate method was used to reliable detect the various clusters in the data sets. Results: In all the four subjects, the pancreatic region was found to be from a different (and unique) cluster. This cluster covered the pancreatic region in all the four subjects. Conclusions: The ISODATA algorithm presented could detect the pancreatic region without manual tracing.

No significant financial relationships to disclose.

Strengthening clinical effectiveness trials: equipoise-stratified randomization

As psychiatric practice patterns evolve to take advantage of the growing list of treatments with proven efficacy, research studies with broader aims will become increasingly important. Randomized trials may need to accommodate multiple treatment options. In completely randomized designs, patients are assigned at random to one of the options, requiring that patients and clinicians find each of the options acceptable. In "clinician's choice" designs, patients are randomized to a small number of broad strategies and the choice of specific option within the broad strategy is left up to the clinician. The clinician's choice design permits some scope to patient and clinician preferences, but sacrifices the ability to make randomization-based comparisons of specific options. We describe a new approach, which we call the "equipoise stratified" design, that merges the advantages and avoids the disadvantages of the other two designs for clinical trials. The three designs are contrasted, using the National Institute of Mental Health Sequenced Treatment Alternatives to Relieve Depression trial as an example.