Diagnosis and treatment of HEp-2 cells contaminated with mycoplasma

Effects and Eradication of Mycoplasma Contamination on Patient-derived Colorectal Cancer Organoid Cultures

Patient-derived organoids are a useful platform for identification and testing of novel precision oncology approaches. Patient-derived organoids are generated by direct culture of patient samples. However, prior to development into patient-derived organoids, these samples are often processed for clinical use, opening the potential for contamination by Mycoplasma and other microbes. While most microbes can be detected by visual inspection, Mycoplasma can go undetected and have substantial impacts on assay results. Given the increased use of patient-derived organoids, there is a growing need for a standardized protocol to detect and remove Mycoplasma from organoid models. In the current study, we report a procedure for Mycoplasma removal by passaging organoids through mice as patient-derived organoid xenografts. In vivo passage of patient-derived organoids followed by re-establishment was 100% effective at decontaminating colorectal patient-derived organoids (n = 9), based on testing with the Sigma LookOut Mycoplasma PCR Detection Kit. This process can serve as a method to re-establish contaminated patient-derived organoids, which represent precious models to study patient-specific genomic features and treatment responses.

SIGNIFICANCE

Organoids are valuable models of cancer. Mycoplasma contamination can alter organoid drug sensitivity, so there is a need for a standardized protocol to detect and remove Mycoplasma from organoids. We report a simple procedure for removing Mycoplasma from organoids via in vivo passaging through mice followed by re-establishment of organoids.

Comparison of different diagnostic modalities for isolation of Mycobacterium Tuberculosis among suspected tuberculous lymphadenitis patients

Tuberculosis is a communicable disease with high morbidity and mortality rates in developing countries. The study's primary objective is to compare conventional methods such as acid-fast bacillus (AFB) culture and microscopy with rapid diagnostic methods. The secondary objective is to compare histopathological and microbiological findings in suspected patients with tubercular lymphadenitis. A total of 111 samples (August 2018 to September 2019) of lymph nodes were processed for AFB microscopy, AFB cultures, drug-susceptibility testing (DST), histopathology, and Xpert Mycobacterium Tuberculosis (MTB)/resistance to Rifampin (RIF) assays. Out of 111 lymph node samples, 6 (5.4%) were positive for AFB smear microscopy, 84 (75.6%) were positive for AFB culture, 80 (70.7%) were positive on Gene Xpert, and 102 (91.8%) were indicative of tuberculosis for histopathology studies. Mycobacteria growth indicator tube (MGIT) culture positivity was 84 (75.6%) higher than solid Lowenstein-Jensen (LJ) culture 74 (66.6%). Positive cultures underwent phenotypic DST. Two cases were Multidrug-resistant (MDR) on DST, while three cases were Rifampicin resistant on Gene Xpert. The sensitivity of Genexpert was (62%) against the conventional AFB culture method. The poor performance of conventional lymphadenitis diagnostic methods requires early and accurate diagnostic methodology. Xpert MTB/RIF test can help in the treatment of multidrug-resistant TB cases. Nonetheless, rapid and conventional methods should be used for complete isolation of Mycobacterium tuberculosis.

Initial assessment of suitability of MCF-7 and HepG2 cancer cell lines for AQP3 research in cancer biology

Cancer cell lines are widely used as in vitro models to elucidate biological processes in cancer, and as a tool to evaluate anticancer agents. In fact, the use of an appropriate cancer cell line in cancer research is crucial for investigating new, potential factors involved in carcinogenesis. One of them is aquaporin-3 (AQP3), which is a small, hydrophobic, integral membrane protein with a predominant role in water and glycerol transport. Recently, altered expression of AQP3 has been reported in many types of cancer. Increasing evidence strongly suggests that AQP3 plays a key role in cancer cell proliferation, migration and invasion. In this study, we performed an insightful characteristic of AQP3 location and its protein expression in MCF-7 human breast adenocarcinoma and HepG2 hepatocellular carcinoma cell lines in the context of cancer biology using immunocytochemistry, immunofluorescence and Western blot analyses. AQP3 was found to be located in the cell membrane and cytoplasm of MCF-7 cells, and in the cytoplasm and nuclear membrane of HepG2 cells. Immunoblotting of proteins derived from both cell lines revealed a clear band with a molecular weight of approx. 30 kDa representing an unglycosylated form of AQP3. However, the expression of this protein was higher in MCF-7 than in HepG2. Concluding, our results clearly indicated variability in both the expression levels and subcellular location of the AQP3 protein in MCF-7 and HepG2 cell lines. This leads to the possibility that the expression patterns and subcellular location of AQP3 in the tested cancer cell lines are tissue-of-origin specific, and may be related to the aggressiveness of cancer cells and their mobility.

Stenotrophomonas maltophilia outer membrane protein A induces epithelial cell apoptosis via mitochondrial pathways

Stenotrophomonas maltophilia (S. maltophilia) is a common opportunistic pathogen in intensive care units and causes infections most often after surgeries in immune-compromised patients such as those undergoing chemotherapy. Outer membrane protein A (OmpA) is the most abundant of the outer membrane proteins in S. maltophilia. Previous studies on OmpA usually focus on its interaction with the host cells and its role in vaccine development. However, the impact of OmpA on the virulence of S. maltophilia to host cells and the effects on apoptosis remain unclear. In this study, we exposed purified recombinant S. maltophilia OmpA (rOmpA) to HEp-2 cells and investigated the effects of OmpA on epithelial cell apoptosis. Morphologic and flow cytometric analyses revealed that HEp-2 cells stimulated with rOmpA multiple apoptosis features, including nuclear roundness and pyknosis, chromatin aggregation, and phosphatidylserine eversion. We found that rOmpA regulated the protein levels of Bax and Bcl-xL in HEp-2 cells, leading to changes in mitochondria permeability and the release of cytochrome c and apoptosis-inducing factors into the cytoplasm. These subsequently activate the caspase-9/caspase-3 pathway that promote apoptosis. We also observed that rOmpA enhanced the generation of reactive oxygen species and increased intracellular Ca²⁺ levels in HEp-2 cells. Collectively, our data suggested that rOmpA induced epithelial cells apoptosis via mi-tochondrial pathways.