Gregor Kijanka

Mater Research Institute - The University of Queensland · Immune Profiling and Cancer Group

BACKGROUND & AIMS Chronic bowel inflammation increases the risk of colon cancer: colitis associated cancer (CAC). Thiopurine use is associated with a reduction in dysplasia and CAC in inflammatory bowel disease (IBD). Abnormal Wnt/β-catenin signalling is characteristic of >90% of colorectal cancers. Immunosuppression by thiopurines is via Rac1 GTPa...

The polymerase chain reaction (PCR) is a robust technique used to make multiple copies of a segment of DNA. However, the available PCR platforms require elaborate and time-consuming operations or costly instruments, hindering their application. Herein, we introduce a sandwiched glass–polydimethylsiloxane (PDMS)–glass microchip containing an array o...

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translate...

Many adenocarcinomas, including colorectal cancer (CRC), overexpress the MUC13 cell surface mucin, but the functional significance and mechanisms are unknown. Here, we report the roles of MUC13 in colonic tumorigenesis and tumor progression. High-MUC13 expression is associated with poor survival in two independent patient cohorts. In a comprehensiv...

Introduction Colorectal cancer is a major public health issue, with incidences continuing to rise owing to the growing and aging world population. Current screening strategies for colorectal cancer diagnosis suffer from various limitations, including invasiveness and poor uptake. Consequently, there is an unmet clinical need for a minimally invasiv...

Background: Stromal gene expression patterns predict patient outcomes in colorectal cancer. TRIM28 is a transcriptional co-repressor that regulates an abundance of genes through the KRAB domain family of transcription factors. We have previously shown that stromal expression of TRIM28 is a marker of disease relapse and poor survival in colorectal...

Protein arrays are frequently used to profile antibody repertoires in humans and animals. High-throughput protein array characterisation of complex antibody repertoires necessitates the use of extensively validated secondary detection antibodies. This article details the validation of an affinity-isolated anti-chicken IgY antibody produced in rabbi...

Mycotoxins are secondary fungal metabolites, which occur in food and feed. They have detrimental effects on the health of humans and animals, and they are known to cause immunosuppression. In this study the effect of patulin, deoxynivalenol (DON), zearalenone (ZEN) and T-2 toxin exposure on the viability and the secretion of key pro- and anti-infla...

Protein arrays are frequently used to profile antibody repertoires in humans and animals. High-throughput protein array characterisation of complex antibody repertoires requires a platform-dependent, lot-to-lot validation of secondary detection antibodies. This article details the validation of an affinity-isolated anti-chicken IgY antibody produce...

Colorectal cancer is one of the most common cancers worldwide with almost 700,000 deaths every year. Detection of colorectal cancer at an early stage significantly improves patient survival. Cancer-specific autoantibodies found in sera of cancer patients can be used for pre-symptomatic detection of the disease. In this study we assess the zinc fing...

We present a substantially improved design and functionality of a centrifugo-magnetophoretic platform which integrates direct immunoseparation and cost-efficient, bright-field detection of cancer cells in whole blood. All liquid handling takes place in a disposable cartridge with geometry akin to a conventional compact disc (CD). The instrumentatio...

Ceramide synthase 5 (CerS5) is involved in the de novo synthesis of ceramide, a sphingolipid involved in cell death and proliferation. In this study, we investigated the role of CerS5 in colorectal cancer (CRC) by examining CerS5 expression, clinico-pathological parameters and association with survival/death signalling pathways in cancer. CerS5 imm...

We report an opto-microfluidic method for continuous and non-interfering monitoring of cell movement and dynamic molecular processes in living cells enabled by the microfluidic "Lab-in-a-Trench" (LiaT) platform. To demonstrate real-time monitoring of heterogeneous cell-cell interactions, cell tracking and agent-induced cell activation dynamics, we...

Table S4. Spearman's Rho correlations for ‘IHC CerS5 Low' RPPA measurements.

Figure S1. Western blot antibody validation for the CerS5 (LS‐B3152). Whole‐cell lysate was prepared from human colon cancer cell line SW620 and standard western blot analysis with the CerS5 (LS‐B3152) antibody was performed.

Table S1. List of primary antibodies used to probe RPPA slides.

Table S2. Relation of CerS5 expression to standard prognostic variables.

Table S5. Spearman's Rho correlations for ‘IHC CerS5 High' RPPA measurements.

Table S3. Normalised relative intensities and total protein for 30 RPPA signalling endpoints.

In this work we present a centrifugal microfluidic system enabling highly efficient collective trapping and alignment of particles such as microbeads and cells, their multi-colour fluorescent detection and subsequent manipulation by optical tweezers. We demonstrate array-based capture and imaging followed by "cherry-picking" of individual particles...

TRIM28 is a universal transcriptional co-repressor with pleotropic effects in both normal and tumor cells. We have previously shown that varying TRIM28 levels in epithelial cells and stromal fibroblasts have a prognostic value in colorectal cancer (CRC) patients (1). The pathophysiological role of TRIM28 in carcinogenesis may therefore be associate...

In medical diagnostics, detection of cells exhibiting specific phenotypes constitutes a paramount challenge. Detection technology must ensure efficient isolation of (often rare) targets while eliminating nontarget background cells. Technologies exist for such investigations, but many require high levels of expertise, expense, and multistep protocol...

Background: Ceramide synthase 5 (CerS5) is multi-pass transmembrane protein of the endoplasmic reticulum. Functioning as a bona fide (dihydro)ceramide synthase, CerS5 regulates the levels of short ceramide species. Ceramides are bioactive lipids implicated in proliferation, senescence, angiogenesis and death of normal and cancerous cells. We aimed...

Background and aim: TRIM28 is a multi-domain nuclear protein with pleotropic effects in both normal and tumor cells. In this study, TRIM28 expression in epithelial and stromal tumor microenvironment and its prognostic role in colorectal cancer were investigated. Methods: Immunohistological staining of TRIM28 was evaluated in tissue microarrays c...

There has been a recent surge of research output on magnetophoretic lab-on-a-chip systems due to their prospective use in a range of applications in the life sciences and clinical diagnostics. Manifold applications for batch-mode or continuous-flow magnetophoretic separations of cells, proteins, and nucleic acids are found in bioanalytics, cell bio...

In this work we for the first time present a technology which pairs up fluorescence based detection / manipulation of individual particles using optical tweezers, with our highly efficient V-cup based trapping scheme. To the best of our knowledge, this is the first time that centrifugal microfluidics and optical tweezers have been combined to perfo...

Over the past two decades, centrifugal microfluidic systems have successfully demonstrated their capability for robust, high-performance liquid handling to enable modular, multi-purpose lab-on-a-chip platforms for a wide range of life-science applications. Beyond the handling of homogeneous liquids, the unique, rotationally controlled centrifugal a...

A coordinated mode of motility is required for dissemination and invasion of esophageal metastases through the vasculature. This motility is largely driven by the activation of GTPases Rac1 and Rab5 which regulate 2 and 3-dimensional motility respectively; however, little is known about the localization and activation of these GTPases under hydrody...

We present a novel centrifugal microfluidic platform for the highly efficient manipulation and analysis of particles for applications in bead-based assays. The platform uses an array of geometrical V-cup barriers to trap particles using stopped-flow sedimentation under highly reproducible hydrodynamic conditions. The impact parameters governing the...

Based on our pioneering work on multi-force, centrifugo-magnetic particle separation presented at μTAS'11 [1] [2], we have substantially improved design (Fig. 1) and functionality to enable the direct immuno-separation of cancer cells from whole blood. The system presented here is shown to successfully extract a population of less than a hundred ca...

Just as the Petri dish has been invaluable to the evolution of biomedical science in the last 100 years, microfluidic cell assay platforms have the potential to change significantly the way modern biology and clinical science are performed. However, an evolutionary process of creating an efficient microfluidic array for many different bioassays is...

This work demonstrates for the first time integrated and highly multiplexable immunoassays on single beads on a centrifugal microfluidic platform. Sharply peaked, single-occupancy distributions of the monodisperse beads are achieved by a stopped-flow, merely sedimentation-based introduction of the beads to an array of scale-matched geometrical barr...

In this work we present a centrifugal microfluidic platform for highly efficient trapping, staining and identification of biological cells. V-shaped geometric traps are used to captured mixed populations of cells under stagnant flow conditions. We demonstrate the capability to discriminate cells based on surface markers (EpCAM) as well as on intrac...

In this work we for the first time demonstrate real-time monitoring of the expression of membrane proteins in native, live cells, free of hydrodynamic stress at single cell resolution. This micro-optofluidic mechanism is uniquely enabled by the intricate interplay of gravity induced sedimentation with laminar flow, fast diffusion and short optical...

Microfluidics offers a unique environment to capture cells and assess cell function. Although many devices have been developed in recent years, maintaining cell integrity remains problematic. In this study, we develop two different microfluidic devices which capture cells with high efficiency, while exposing cells to minimal stress. Both systems ar...

Many diagnostic antibodies are generated by immunization with whole cells or cell extracts and are shown by screening on tissue sections to label specific cell populations. However, their target molecule then needs to be identified, and this can be technically demanding. Here we describe the use of protein arrays to define the targets of new or unc...

Patients with cancer have antibodies against tumour antigens. Characterising the antibody repertoire may provide insights into aberrant cellular mechanisms in cancer development, ultimately leading to novel diagnostic or therapeutic targets. The aim of this study was to characterise the antibody profiles in patients whose symptoms warranted colonos...

Protein array technology has begun to play a significant role in the study of protein-protein interactions and in the identification of antigenic targets of serum autoantibodies in a variety of autoimmune disorders. More recently, this technology has been applied to the identification of autoantibody signatures in cancer. The identification of tumo...

Antibodies are routinely used as research tools, in diagnostic assays and increasingly as therapeutics. Ideally, these applications require antibodies with high sensitivity and specificity; however, many commercially available antibodies are limited in their use as they cross-react with non-related proteins. Here we describe a novel method to chara...

Automation is the key approach for genomewide and proteomewide screening of function and interaction. Especially for proteomics, antibody microarrays are a useful tool for massive parallel profiling of complex samples. To meet the requirements of antibody microarrays and to obtain a great variety of antibodies, new technologies such as phage displa...

This paper describes two centrifugal microfluidic platforms for advanced handling and detection of particles and biological cells. A broad repertoire of novel, high-performance trapping, arraying, sorting, assaying, staining, identification and counting techniques are uniquely enabled by a favorable combination of the centrifugal force with several...