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Glioblastoma (GBM), a WHO grade IV glioma, is a malignant primary brain tumour for which combination of surgery, chemotherapy and radiotherapy is the first-line approach despite adverse effects. Tumour microenvironment (TME) is characterized by an interplay of cells and soluble factors holding a critical role in neoplastic development. Significant pathophysiological changes have been found in GBM TME, such as glia activation and oxidative stress. Microglia play a crucial role in favouring GBM growth, representing target cells of immune escape mechanisms. Our study aims at analysing radiation-induced effects in modulating intercellular communication and identifying the basis of protective mechanisms in radiation-naïve GBM cells. Tumour cells were treated with conditioned media (CM) derived from 0, 2 or 15 Gy irradiated GBM cells or 0, 2 or 15 Gy irradiated human microglia. We demonstrated that irradiated microglia promote an increase of GBM cell lines proliferation through paracrine signalling. On the contrary, irradiated GBM-derived CM affect viability, triggering cell death mechanisms. In addition, we investigated whether these processes involve mitochondrial mass, fitness and oxidative phosphorylation and how GBM cells respond at these induced alterations. Our study suggests that off-target radiotherapy modulates microglia to support GBM proliferation and induce metabolic modifications., (© 2024 The Authors. Cell Proliferation published by Beijing Institute for Stem Cell and Regenerative Medicine and John Wiley & Sons Ltd.)

Second-generation tyrosine kinase inhibitors (2GTKI) are more effective in inducing rapid molecular responses than imatinib when used first-line in patients with chronic myeloid leukemia in chronic phase (CML-CP). However, failure of first line-2GTKI (1L-2GTKI) still occurs and there is no consensus regarding subsequent management. We retrospectively analyzed the outcome of 106 CML-CP patients treated with 1L-2GTKI and with a median follow-up of 91 months. 45 patients (42.4%) switched to an alternative TKI, 28 for intolerance (26.4%) and 17 (16%) for resistance. Most patients who remained on 1L-2GTKI achieved deep molecular responses (DMR) and 15 (14.1%) are in treatment-free remission (TFR). Intolerant patients also obtained DMR, although most required multiple TKI changes and were slower to respond, particularly if treated with 2L-imatinib. Inferior outcomes were observed in resistant patients, who failed alternative 2L-2GTKI and required 3/4GTKI and/or allogeneic hematopoietic stem cell transplant (alloSCT). 7yr-OS was significantly lower for these individuals (66.1%) than for intolerant patients and those who remained on 1L-2GTKI (100% and 97.9%, respectively; p = 0.001). It is apparent that failure of 1L-2GTKI is a challenging problem in modern CML therapy. Intolerance can be effectively managed by switching to an alternative 2GTKI, but resistance requires early consideration of 3/4GTKI., (© 2024. The Author(s).)

Mesenchymal stromal cells (MSCs) are a subset of heterogeneous, non-hematopoietic fibroblast-like cells which play important roles in tissue repair, inflammation, and immune modulation. MSCs residing in the bone marrow microenvironment (BMME) functionally interact with hematopoietic stem progenitor cells regulating hematopoiesis. However, MSCs have also emerged in recent years as key regulators of the tumor microenvironment. Indeed, they are now considered active players in the pathophysiology of hematologic malignancies rather than passive bystanders in the hematopoietic microenvironment. Once a malignant event occurs, the BMME acquires cellular, molecular, and epigenetic abnormalities affecting tumor growth and progression. In this context, MSC behavior is affected by signals coming from cancer cells. Furthermore, it has been shown that stromal cells themselves play a major role in several hematological malignancies' pathogenesis. This bidirectional crosstalk creates a functional tumor niche unit wherein tumor cells acquire a selective advantage over their normal counterparts and are protected from drug treatment. It is therefore of critical importance to unveil the underlying mechanisms which activate a protumor phenotype of MSCs for defining the unmasked vulnerabilities of hematological cancer cells which could be pharmacologically exploited to disrupt tumor/MSC coupling. The present review focuses on the current knowledge about MSC dysfunction mechanisms in the BMME of hematological cancers, sustaining tumor growth, immune escape, and cancer progression.

Metabolic changes of malignant plasma cells (PCs) and adaptation to tumour microenvironment represent one of the hallmarks of multiple myeloma (MM). We previously showed that MM mesenchymal stromal cells are more glycolytic and produce more lactate than healthy counterpart. Hence, we aimed to explore the impact of high lactate concentration on metabolism of tumour PCs and its impact on the efficacy of proteasome inhibitors (PIs). Lactate concentration was performed by colorimetric assay on MM patient's sera. The metabolism of MM cell treated with lactate was assessed by seahorse and real time Polymerase Chain Reaction (PCR). Cytometry was used to evaluate mitochondrial reactive oxygen species (mROS), apoptosis and mitochondrial depolarization. Lactate concentration resulted increased in MM patient's sera. Therefore, PCs were treated with lactate and we observed an increase of oxidative phosphorylation-related genes, mROS and oxygen consumption rate. Lactate supplementation exhibited a significant reduction in cell proliferation and less responsive to PIs. These data were confirmed by pharmacological inhibition of monocarboxylate transporter 1 (MCT1) by AZD3965 which was able to overcame metabolic protective effect of lactate against PIs. Consistently, high levels of circulating lactate caused expansion of Treg and monocytic myeloid derived suppressor cells and such effect was significantly reduced by AZD3965. Overall, these findings showed that targeting lactate trafficking in TME inhibits metabolic rewiring of tumour PCs, lactate-dependent immune evasion and thus improving therapy efficacy., (© 2023 The Authors. Cell Proliferation published by Beijing Institute for Stem Cell and Regenerative Medicine and John Wiley & Sons Ltd.)

Dielectrophoresis (DEP) represents an electrokinetic approach for discriminating and separating suspended cells based on their intrinsic dielectric characteristics without the need for labeling procedure. A good practice, beyond the physical and engineering components, is the selection of a buffer that does not hinder cellular and biochemical parameters as well as cell recovery. In the present work the impact of four buffers on biochemical, morphological, and mechanical parameters was evaluated in two different cancer cell lines (Caco-2 and K562). Specifically, MTT ([3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide]) assay along with flow cytometry analysis were used to evaluate the occurring changes in terms of cell viability, morphology, and granulocyte stress formation, all factors directly influencing DEP sorting capability. Quantitative real-time PCR (qRT-PCR) was instead employed to evaluate the gene expression levels of interleukin-6 (IL-6) and inducible nitric oxide synthase (iNOS), two well-known markers of inflammation and oxidative stress, respectively. An additional marker representing an index of cellular metabolic status, i.e. the expression of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene, was also evaluated. Among the four buffers considered, two resulted satisfactory in terms of cell viability and growth recovery (24 h), with no significant changes in cell morphology for up to 1 h in suspension. Of note, gene expression analysis showed that in both cell lines the apparently non-cytotoxic buffers significantly modulated IL-6, iNOS, and GAPDH markers, underlining the importance to deeply investigate the molecular and biochemical changes occurring during the analysis, even at apparently non-toxic conditions. The selection of a useful buffer for the separation and analysis of cells without labeling procedures, preserving cell status, represents a key factor for DEP analysis, giving the opportunity to further use cells for additional analysis., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Copyright © 2022. Published by Elsevier Inc.)

Background: Docetaxel improves overall survival (OS) in castration-resistant prostate cancer (PCa) (CRPC) and metastatic hormone-sensitive PCa (mHSPC). However, not all patients respond due to inherent and/or acquired resistance. There remains an unmet clinical need for a robust predictive test to stratify patients for treatment. Liquid biopsy of circulating tumour cell (CTCs) is minimally invasive, can provide real-time information of the heterogeneous tumour and therefore may be a potentially ideal docetaxel response prediction biomarker., Objective: In this study we investigate the potential of using CTCs and their gene expression to predict post-docetaxel tumour response, OS and progression free survival (PFS)., Methods: Peripheral blood was sampled from 18 mCRPC and 43 mHSPC patients, pre-docetaxel treatment, for CTC investigation. CTCs were isolated using the epitope independent Parsortix ® system and gene expression was determined by multiplex RT-qPCR. We evaluated CTC measurements for post-docetaxel outcome prediction using receiver operating characteristics and Kaplan Meier analysis., Results: Detection of CTCs pre-docetaxel was associated with poor patient outcome post-docetaxel treatment. Combining total-CTC number with PSA and ALP predicted lack of partial response (PR) with an AUC of 0.90, p= 0.037 in mCRPC. A significantly shorter median OS was seen in mCRPC patients with positive CTC-score (12.80 vs. 37.33 months, HR= 5.08, p= 0.0005), ≥3 total-CTCs/7.5mL (12.80 vs. 37.33 months, HR= 3.84, p= 0.0053), ≥1 epithelial-CTCs/7.5mL (14.30 vs. 37.33 months, HR= 3.89, p= 0.0041) or epithelial to mesenchymal transitioning (EMTing)-CTCs/7.5mL (11.32 vs. 32.37 months, HR= 6.73, p= 0.0001). Significantly shorter PFS was observed in patients with ≥2 epithelial-CTCs/7.5mL (7.52 vs. 18.83 months, HR= 3.93, p= 0.0058). mHSPC patients with ≥5 CTCs/7.5mL had significantly shorter median OS (24.57 vs undefined months, HR= 4.14, p= 0.0097). In mHSPC patients, expression of KLK2 , KLK4 , ADAMTS1 , ZEB1 and SNAI1 was significantly associated with shorter OS and/or PFS. Importantly, combining CTC measurements with clinical biomarkers increased sensitivity and specificity for prediction of patient outcome., Conclusion: While it is clear that CTC numbers and gene expression were prognostic for PCa post-docetaxel treatment, and CTC subtype analysis may have additional value, their potential predictive value for docetaxel chemotherapy response needs to be further investigated in large patient cohorts., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Davies, Guo, Burke, Stankiewicz, Xu, Mao, Scandura, Rajan, Tipples, Alifrangis, Wimalasingham, Galazi, Crusz, Powles, Grey, Oliver, Kudahetti, Shaw, Berney, Shamash and Lu.)

In multiple myeloma (MM), circulating tumor plasma cells (CTPCs) are an emerging prognostic factor, offering a promising and minimally invasive means for longitudinal patient monitoring. Recent advances highlight the complex biology of plasma cell trafficking, highlighting the phenotypic and genetic signatures of intra- and extra-medullary MM onset, making CTPC enumeration and characterization a new frontier of precision medicine for MM patients, requiring novel technological platforms for their standardized and harmonized detection. Dielectrophoresis (DEP) is an emerging label-free cell manipulation technique to separate cancer cells from healthy cells in peripheral blood samples, based on phenotype and membrane capacitance that could be successfully tested to enumerate and isolate CTPCs. Herein, we summarize preclinical data on DEP development for CTPC detection, as well as their clinical and research potential.

Relapse in multiple myeloma (MM) decreases therapy efficiency through unclear mechanisms of chemoresistance. Since our group previously demonstrated that heme oxygenase-1 (HO-1) and Toll-like receptor 4 (TLR4) are two signaling pathways protecting MM cells from the proteasome inhibitor bortezomib (BTZ), we here evaluated their cross-regulation by a pharmacological approach. We found that cell toxicity and mitochondrial depolarization by BTZ were increased upon inhibition of HO-1 and TLR4 by using tin protoporphyrin IX (SnPP) and TAK-242, respectively. Furthermore, the combination of TAK-242 and BTZ activated mitophagy and decreased the unfolded protein response (UPR) survival pathway in association with a downregulation in HO-1 expression. Notably, BTZ in combination with SnPP induced effects mirroring the treatment with TAK-242/BTZ, resulting in a blockade of TLR4 upregulation. Interestingly, treatment of cells with either hemin, an HO-1 inducer, or supplementation with carbon monoxide (CO), a by-product of HO-1 enzymatic activity, increased TLR4 expression. In conclusion, we showed that treatment of MM cells with BTZ triggers the TLR4/HO-1/CO axis, serving as a stress-responsive signal that leads to increased cell survival while protecting mitochondria against BTZ and ultimately promoting drug resistance.