The Role of Chaperone-Mediated Autophagy in Bortezomib Resistant Multiple Myeloma

Background: Multiple myeloma (MM) remains incurable despite high-dose chemotherapy, autologous stem cell transplants and novel agents. Even with the improved survival of MM patients treated with novel agents, including bortezomib (Bz), the therapeutic options in relapsed/refractory MM remain limited. The majority of MM patients eventually develop resistance to Bz, although the mechanisms of the resistance are poorly understood. Methods: Lysosomal associated membrane protein 2A (LAMP2A) mRNA and protein expression levels were assessed in ex vivo patient samples and a Bz-resistant MM cell line model by in real-rime PCR, western blotting and immunohistochemistry. In vitro modelling of chaperone-mediated autophagy (CMA) activity in response to ER stress were assessed by western blotting and confocal microscopy. The effects of CMA inhibition on MM cell viability and Bz sensitivity in MM cells were assessed by Annexin V/7AAD apoptosis assays using flow cytometry. Results: In this study, there is evidence that CMA, a chaperone-mediated protein degradation pathway, is upregulated in Bz-resistant MM and the inhibition of CMA sensitises resistant cells to Bz. The protein levels of LAMP2A, the rate-limiting factor of the CMA pathway, are significantly increased in MM patients resistant to Bz and within our Bz-resistant cell line model. Bz-resistant cell lines also possessed higher basal CMA activity than the Bz-sensitive parent cell line. In MM cell lines, CMA activity was upregulated in response to ER stress induced by Bz. The inhibition of CMA sensitises Bz-resistant cells to Bz and the combination of CMA inhibition and Bz in vitro had a more cytotoxic effect on myeloma cells than Bz alone. Conclusion: In summary, the upregulation of CMA is a potential mechanism of resistance to Bz and a novel target to overcome Bz-resistant MM.

A Human Osteocyte Cell Line Model for Studying Staphylococcus aureus Persistence in Osteomyelitis

Infectious osteomyelitis associated with periprosthetic joint infections is often recalcitrant to treatment and has a high rate of recurrence. In the case of Staphylococcus aureus, the most common pathogen in all forms of osteomyelitis, this may be attributed in part to residual intracellular infection of host cells, yet this is not generally considered in the treatment strategy. Osteocytes represent a unique cell type in this context due to their abundance, their formation of a syncytium throughout the bone that could facilitate bacterial spread and their relative inaccessibility to professional immune cells. As such, there is potential value in studying the host-pathogen interactions in the context of this cell type in a replicable and scalable in vitro model. Here, we examined the utility of the human osteosarcoma cell line SaOS2 differentiated to an osteocyte-like stage (SaOS2-OY) as an intracellular infection model for S. aureus. We demonstrate that S. aureus is capable of generating stable intracellular infections in SaOS2-OY cells but not in undifferentiated, osteoblast-like SaOS2 cells (SaOS2-OB). In SaOS2-OY cells, S. aureus transitioned towards a quasi-dormant small colony variant (SCV) growth phenotype over a 15-day post-infection period. The infected cells exhibited changes in the expression of key immunomodulatory mediators that are consistent with the infection response of primary osteocytes. Thus, SaOS2-OY is an appropriate cell line model that may be predictive of the interactions between S. aureus and human osteocytes, and this will be useful for studying mechanisms of persistence and for testing the efficacy of potential antimicrobial strategies.

Microbe-Mediated Activation of Toll-like Receptor 2 Drives PDL1 Expression in HNSCC

As immunotherapies targeting the PDL1 checkpoint have become a mainstay of treatment for a subset of head and neck squamous cell carcinoma (HNSCC) patients, a detailed understanding of the mechanisms underlying PDL1-mediated immune evasion is needed. To elucidate factors regulating expression of PDL1 in HNSCC cells, a genome-wide CRISPR profiling approach was implemented to identify genes and pathways conferring altered PDL1 expression in an HNSCC cell line model. Our screen nominated several candidate PDL1 drivers, including Toll-like Receptor 2 (TLR2). Depletion of TLR2 blocks interferon-γ-induced PDL1 expression, and stimulation of TLR2 with either Staphylococcus aureus or a bacterial lipopeptide mimetic, Pam3CSK4, enhanced PDL1 expression in multiple models. The data herein demonstrate a role for TLR2 in modulating the expression of PDL1 in HNSCC models and suggest that microbiota may directly modulate immunosuppression in cancer cells. Our study represents a step toward disentangling the diverse pathways and stimuli regulating PDL1 expression in HNSCC and underscores a need for future work to characterize the complex microbiome in HNSCC patients treated with immunotherapy.

A Customisable Cell Line Model of Glioblastoma

<p><b>Glioblastoma is an extremely malignant brain tumour with one of the lowest survival rates of all cancers. Current treatments do very little to alter this prognosis. Research into new therapies and the biology of glioblastoma has made scarce progress over the past decades. This is partly due to the combination of the tumour’s heterogeneity, and the inability of the current animal models to accurately depict this. This project was a pilot study into the development and characterisation of a novel cell line model of glioblastoma, which could be transplanted into immune competent mice, in order to study the disease.</b></p> <p>An immortalised C57BL/6 astrocyte cell line, with an EGFP transgene, was used as the base to add glioblastoma specific mutations. To produce a ‘classical-like’ glioblastoma model, a knockout in Pten was induced, onto which two separate lines the human oncogenes, EGFRVIII and RAS V12, were stably expressed. ‘Secondary-like’ models were created with a knockout of P53, and the stable transfection of IDH1R132H.</p> <p>The ‘classical-like’ cell lines were assessed for how well they mimicked a classical glioblastoma. The Pten knockout cell line showed an increased proliferative and metabolic rate compared with the astrocytes and a significant increase in clonogenicity. The addition of RAS V12 to the cells showed an increased migratory capacity; and the Pten + EGFRVIII cell line had a tendency towards an increased proliferation. The ‘secondary-like’ cell lines were assessed for their survival-related phenotypes. The P53 cell line showed a decreased proliferative rate, but with an increased metabolic rate and clonogenic ability. The introduction of the IDH1 mutant protein resulted in a decreased rate of G2 arrest in response to ionising radiation.</p> <p>These cell lines recapitulated what is seen in human glioblastoma tumours and show potential as a transplantation model. Future research will investigate the tumorigenicity of these cell lines.</p>

A Customisable Cell Line Model of Glioblastoma

<p><b>Glioblastoma is an extremely malignant brain tumour with one of the lowest survival rates of all cancers. Current treatments do very little to alter this prognosis. Research into new therapies and the biology of glioblastoma has made scarce progress over the past decades. This is partly due to the combination of the tumour’s heterogeneity, and the inability of the current animal models to accurately depict this. This project was a pilot study into the development and characterisation of a novel cell line model of glioblastoma, which could be transplanted into immune competent mice, in order to study the disease.</b></p> <p>An immortalised C57BL/6 astrocyte cell line, with an EGFP transgene, was used as the base to add glioblastoma specific mutations. To produce a ‘classical-like’ glioblastoma model, a knockout in Pten was induced, onto which two separate lines the human oncogenes, EGFRVIII and RAS V12, were stably expressed. ‘Secondary-like’ models were created with a knockout of P53, and the stable transfection of IDH1R132H.</p> <p>The ‘classical-like’ cell lines were assessed for how well they mimicked a classical glioblastoma. The Pten knockout cell line showed an increased proliferative and metabolic rate compared with the astrocytes and a significant increase in clonogenicity. The addition of RAS V12 to the cells showed an increased migratory capacity; and the Pten + EGFRVIII cell line had a tendency towards an increased proliferation. The ‘secondary-like’ cell lines were assessed for their survival-related phenotypes. The P53 cell line showed a decreased proliferative rate, but with an increased metabolic rate and clonogenic ability. The introduction of the IDH1 mutant protein resulted in a decreased rate of G2 arrest in response to ionising radiation.</p> <p>These cell lines recapitulated what is seen in human glioblastoma tumours and show potential as a transplantation model. Future research will investigate the tumorigenicity of these cell lines.</p>

Nanoparticles derived from insect exoskeleton modulates NLRP3 inflammasome complex activation in cervical cancer cell line model

Background Immune evasion is an important hallmark of cancer progression and tumourigenesis. Among the cancer types, cervical cancer has very high global prevalence, severely affecting female reproductive health. Its preponderance is also observed in the Indian health sector. Results The NLRP3 inflammasome, an intracellular complex regulates the innate immune activity and a variant gene of it has been significantly associated with cervical cancer development. We aimed to evaluate the potential role of our chitosan engineered nanoparticles (CSNP) and gallic acid conjugated chitosan (gCSNP), to modulate the NLRP3 inflammasome complex in cervical cancer cell lines to explore their novel physicochemical properties. The encapsulation of gallic acid (GA) with chitosan was performed using ion gelation method. The CSNP and gCSNP nanoparticles ranged between 155 and 181 nm as determined by zeta sizer. The conjugations were validated by FTIR and XRD analysis. In the cervical cell line model, CSNP suppressed NLRP3 inflammasome activation in contrast to gCSNP at higher doses. Conclusion In contrast to gCSNP, the CSNP not only demonstrated inhibitory effect on the expression of genes coding for the NLRP3 inflammasome complex (signal 1—priming), but also decreased relative expression of gene involved in the activation of NLRP3 inflammasome complex (signal 2—activation). Conjugation of gallic acid reversed the immunosuppressor mimicking action of CSNP in cervical cancer cell line. Future research can reveal the immunomodulatory mechanism of CSNP may have its translational significance as potential treatment strategies targeting immune evasion as an important hallmark of cancer. Graphical abstract

Characterization of Alternatively Spliced Isoforms of MUC4 and ADAM12 Genes in a Metastatic Colorectal Cancer Cell Line Model

Colorectal cancer prognosis get worse with advancement of disease into metastatic stage. There is a pertinent need to develop prognostic biomarkers that can be used for personalized and precision medicine. Alternative splicing provides an insight into understanding of changes at isoform expression level which may not be evident at gene level. In this direction, we utilized our prior knowledge about significant alternatively spliced genes and chose ADAM12 and MUC4 for further characterization in a metastatic cell line model. These genes were found to be good prognostic indicators in The Cancer Genome Atlas database. We studied the gene organization and designed primers to specifically amplify a group of isoforms. Differential expression of these group of isoforms was observed in normal, primary and metastatic colorectal cancer cell lines. We further validated the results using sanger sequencing. Isoform expression was found to respond to the 5-fluorouracil treatment. RNAseq analysis of the cell lines further validated the differential expression of gene isoforms. Successful detection of ADAM12 and MUC4 in cell lysates varied according to the antibody used which may reflect differential expression of isoforms. This comprehensive study underscores the importance of studying alternatively spliced isoforms and their probable used as prognostic or predictive biomarkers.

Characterization of Alternatively Spliced Isoforms of MUC4 and ADAM12 Genes in a Metastatic Colorectal Cancer Cell Line Model

Colorectal cancer prognosis get worse with advancement of disease into metastatic stage. There is a pertinent need to develop prognostic biomarkers that can be used for personalized and precision medicine. Alternative splicing provides an insight into understanding of changes at isoform expression level which may not be evident at gene level. In this direction, we utilized our prior knowledge about significant alternatively spliced genes and chose ADAM12 and MUC4 for further characterization in a metastatic cell line model. These genes were found to be good prognostic indicators in The Cancer Genome Atlas database. We studied the gene organization and designed primers to specifically amplify a group of isoforms. Differential expression of these group of isoforms was observed in normal, primary and metastatic colorectal cancer cell lines. We further validated the results using sanger sequencing. Isoform expression was found to respond to the 5-fluorouracil treatment. RNAseq analysis of the cell lines further validated the differential expression of gene isoforms. Successful detection of ADAM12 and MUC4 in cell lysates varied according to the antibody used which may reflect differential expression of isoforms. This comprehensive study underscores the importance of studying alternatively spliced isoforms and their probable used as prognostic or predictive biomarkers.