Freshly isolated bone marrow cells induce death of various carcinoma cell lines

Paracrine Factors Released from Tonsil-Derived Mesenchymal Stem Cells Inhibit Proliferation of Hematological Cancer Cells Under Hyperthermia in Co-culture Model

Mesenchymal stem cells (MSCs) are promising biological therapeutic candidates in cancer treatment. As a source of MSCs, palatine tonsil tissue is one of the secondary lymphoid organs that form an essential part of the immune system, and the relation between the secondary lymphoid organs and cancer progression leads us to investigate the effect of tonsil-derived MSCs (T-MSC) on cancer treatment. We aimed to determine the anti-tumoral effects of T-MSCs cultured at the febrile temperature (40 °C) on hematological cancer cell lines. The co-culture of cancer cells with T-MSCs was carried out under fever and normal culture conditions, and then the cell viability was determined by cell counting. In addition, apoptosis rate and cell cycle arrest were determined by flow cytometry. We confirmed the apoptotic effect of T-MSC co-culture at the transcriptional level by using real-time polymerase chain reaction (RT-PCR). We found that co-culture of cancer cells with T-MSCs significantly decreased the viable cell number under the febrile and normal culture conditions. Besides, the T-MSC co-culture induced apoptosis on K562 and MOLT-4 cells and induced the cell cycle arrest at the G2/M phase on MOLT-4 cells. The apoptotic effect of T-MSC co-culture under febrile stimulation was confirmed at the transcriptional level. Our study has highlighted the anti-tumoral effect of the cellular interaction between the T-MSCs and human hematological cancer cells during in vitro co-culture under hyperthermia.

New insights in application of mesenchymal stem cells therapy in tumor microenvironment: pros and cons

Multipotent mesenchymal stem cells (MSCs) are widely accepted as a useful tool for cell-based therapy of various diseases including malignancies. The therapeutic effects of MSCs are mainly attributed to their immunomodulatory and immunosuppressive properties. Despite the promising outcomes of MSCs in cancer therapy, a growing body of evidence implies that MSCs also show tumorigenic properties in the tumor microenvironment (TME), which might lead to tumor induction and progression. Owing to the broad-spectrum applications of MSCs, this challenge needs to be tackled so that they can be safely utilized in clinical practice. Herein, we review the diverse activities of MSCs in TME and highlight the potential methods to convert their protumorigenic characteristics into onco-suppressive effects.

Immune profiling of the bone marrow microenvironment in patients with high-risk localized prostate cancer

Bone marrow (BM) is a primary metastatic site in prostate cancer (PC) and bone invasion is considered incurable. T cell-mediated immune surveillance is essential in controlling both tumorigenesis and initiation of metastases. Beside tropism, dissemination of PC cells to the BM may be facilitated by defects in BM immune homeostasis predisposing this niche to colonization.

To evaluate the BM immune microenvironment in locally advanced, non-metastatic PC, we performed flow cytometry analysis of myeloid and lymphoid subsets in BM aspirates and peripheral blood collected during prostatectomy. Healthy BM aspirates served to establish a reference range for comparison.

We found alterations in BM immune composition of PC patients, including an increased CD4/CD8 ratio, enrichment of CD4⁺ T cells, increased CD56⁺CD3⁺ NKT and CD56⁺CD3^- NK yields compared to healthy controls. The lymphoid phenotype remained comparable regarding T cell activation and chemokine receptor-based polarization patterns. Additionally, we found increased B7H3 expression in the myeloid monocyte/macrophage subset and decreased DC infiltration in BM of PC patients.

These findings suggest that alterations in the immune milieu may limit immune surveillance that compromise the ability of the BM microenvironment to prevent tumor dissemination, and predispose development of bone metastases in a subset of patients with localized PC.

Mesenchymal stem cells as carriers for systemic delivery of oncolytic viruses

Progress in genetic engineering led to the emergence of some viruses as potent anticancer therapeutics. These oncolytic viruses combine self-amplification with dual antitumor action: oncolytic (destruction of cancer cells) and immunostimulatory (eliciting acquired antitumor response against cancer epitopes). As any other viruses, they trigger antiviral response upon systemic administration. Mesenchymal stem cells are immature cells capable of self-renewing and differentiating into many cell types that belong to three germinal layers. Due to their inherent tumor tropism mesenchymal stem cells loaded with oncolytic virus can improve delivery of the therapeutic cargo to cancer sites. Shielding of oncolytic viral construct from antiviral host immune response makes these cells prospective delivery vehicles to even hard-to-reach metastatic neoplastic foci. Use of mesenchymal stem cells has been criticized by some investigators as limiting proliferative abilities of primary cells and increasing the risk of malignant transformation, as well as attenuating therapeutic responses. However, majority of preclinical studies indicate safety and efficacy of mesenchymal stem cells used as carriers of oncolytic viruses. In view of contradictory postulates, the debate continues. The review discusses mesenchymal stem cells as carriers for delivery of genetically engineered oncolytic constructs and focuses on systemic approach to oncoviral treatment of some deadly neoplasms.

B procyanidins of Annona crassiflora fruit peel inhibited glycation, lipid peroxidation and protein-bound carbonyls, with protective effects on glycated catalase

Advanced glycation end-products (AGEs) have been reported as results of increased oxidative stress. Consequently, the search for new antioxidant and anti-glycating agents is under intense investigation. Plant-derived procyanidins have previously demonstrated anti-glycation properties. Thus, this study aimed to isolate procyanidins from Annona crassiflora fruit peel, a species from the Brazilian Savanna, and investigate their antioxidant and anti-glycation effects. Free radical scavenging and quenching properties, formation of reactive oxygen species (ROS), AGEs, protein carbonyl and thiol groups, lipid peroxidation, crosslinked AGEs, as well as glycated catalase activity, were analyzed. In addition, in silico assessment of absorption, distribution, metabolism, excretion and toxicity was carried out. The procyanidins-enriched fraction, named here as F7, showed high antioxidant and anti-glycation capacities, with inhibitory activities against lipid peroxidation, and AGEs and ROS formation. In addition, there were reductions in AGEs-induced crosslinks and protein carbonyls and protective effects against oxidation of thiol groups and glycated-catalase. ADMET predictions of F7 showed favorable absorption and distribution, with no hepatotoxicity or mutagenicity. Together, our results support the anti-glycation activities of the procyanidins-enriched fraction from A. crassiflora, and suggest that these effects are triggered, at least in part, by scavenging free radical and dicarbonyls intermediates.

Protective effects of a polyphenol-enriched fraction of the fruit peel of Annona crassiflora Mart. on acute and persistent inflammatory pain

Different parts of Annona crassiflora Mart., a native species from Brazilian savanna, were traditionally used for the treatment of a wide variety of ailments including arthritis. Thus, this study aimed to investigate the possible antinociceptive and anti-inflammatory properties of a polyphenol-enriched fraction of the fruit peel of A. crassiflora, named here as EtOAc, in mice. Pro-inflammatory cytokines and nitric oxide (NO) production were evaluated in LPS-activated macrophages. Then, EtOAc fraction was administered by oral route in male C57BL/6/J mice, and the animals were submitted to glutamate-induced nociception and complete Freund's adjuvant (CFA)-induced monoarthritis tests to assess nociception (mechanical, spontaneous and cold pain) and inflammation (edema and neutrophil infiltration), and to the open-field and rotarod tests for motor performance analysis. EtOAc fraction inhibited the production of IL-6 and NO in the LPS-induced macrophages, and reduced spontaneous nociception induced by glutamate, without altering the animals' locomotor activity. In addition, the polyphenol-enriched fraction was able to revert the early and late hyperalgesia induced by CFA, as well as edema at the acute phase. Reduction of myeloperoxidase activity and inflammatory cell infiltration was observed in the paw tissue of mice injected with CFA and treated with EtOAc fraction. Together, our results support the antinociceptive and anti-inflammatory effects of the polyphenol-enriched fraction of A. crassiflora fruit peel and suggest that these effects are triggered, at least in part, by suppressing pro-inflammatory cytokines and neutrophils infiltration.

Mesenchymal stem cells in preclinical cancer cytotherapy: a systematic review

Mesenchymal stem cells (MSC) comprise a heterogeneous population of rapidly proliferating cells that can be isolated from adult (e.g., bone marrow, adipose tissue) as well as fetal (e.g., umbilical cord) tissues (termed bone marrow (BM)-, adipose tissue (AT)-, and umbilical cord (UC)-MSC, respectively) and are capable of differentiation into a wide range of non-hematopoietic cell types. An additional, unique attribute of MSC is their ability to home to tumor sites and to interact with the local supportive microenvironment which rapidly conceptualized into MSC-based experimental cancer cytotherapy at the turn of the century. Towards this purpose, both naïve (unmodified) and genetically modified MSC (GM-MSC; used as delivery vehicles for the controlled expression and release of antitumorigenic molecules) have been employed using well-established in vitro and in vivo cancer models, albeit with variable success. The first approach is hampered by contradictory findings regarding the effects of naïve MSC of different origins on tumor growth and metastasis, largely attributed to inherent biological heterogeneity of MSC as well as experimental discrepancies. In the second case, although the anti-cancer effect of GM-MSC is markedly improved over that of naïve cells, it is yet apparent that some protocols are more efficient against some types of cancer than others. Regardless, in order to maximize therapeutic consistency and efficacy, a deeper understanding of the complex interaction between MSC and the tumor microenvironment is required, as well as examination of the role of key experimental parameters in shaping the final cytotherapy outcome. This systematic review represents, to the best of our knowledge, the first thorough evaluation of the impact of experimental anti-cancer therapies based on MSC of human origin (with special focus on human BM-/AT-/UC-MSC). Importantly, we dissect the commonalities and differences as well as address the shortcomings of work accumulated over the last two decades and discuss how this information can serve as a guide map for optimal experimental design implementation ultimately aiding the effective transition into clinical trials.

Lymph node micrometastases are associated with disease recurrence and poor survival for early-stage non-small cell lung cancer patients: a meta-analysis

BACKGROUND

We performed a meta-analysis to clarify whether the molecular detection of tumor cells or micrometastases in the lymph node (LN) indicates a high risk of disease recurrence and poor survival in negative pathologic lymph node status non-small cell lung cancer (NSCLC).

METHODS

A literature search was performed using relevant keywords. We searched relevant studies from PubMed, Embase, and the Cochrane Library. Direct and indirect meta-estimates were generated using Review Manager software with fixed effects for the study. Study-to-study heterogeneity was summarized using I (2) statistics and predictive intervals (PIs).

RESULTS

Our analysis of eight eligible studies revealed that patients with lymph node micrometastases (LNMM) were associated with poor overall survival (OS) (HR, 1.98; 95 % CI, 1.50 to 2.62; p < 0.00001) and disease-free survival (DFS) (HR, 2.34; 95 % CI, 1.67-3.27; p < 0.00001).

CONCLUSION

LNMM is associated with an increased risk of disease recurrence and poor survival in patients with negative pathologic node negative NSCLC. Thus, these patients need to be carefully followed up after the initial pulmonary resection.

Bone marrow micrometastasis is associated with both disease recurrence and poor survival in surgical patients with node-negative non-small-cell lung cancer: a meta-analysis

OBJECTIVES

We performed a meta-analysis in order to determine whether the molecular tumour cell detection of either micrometastasis or isolated tumour cells in the bone marrow micrometastasis is indicative of a high risk of both disease recurrence and poor survival in the setting of node-negative non-small-cell lung cancer (NSCLC).

METHODS

Before beginning this study, a rigorous protocol was established in accordance with the recommendations of the Cochrane Collaboration. A systematic literature search of Medline, EMbase, the Cochrane Library and the Web of Science was conducted in order to identify studies regarding the prognostic value of molecular tumour cell detection in the bone marrow of node-negative NSCLC. Any study describing the use of both immunochemistry and flow cytometry to detect bone marrow metastasis was selected. We extracted the associated 95% confidence intervals (CIs) and hazard ratios (HRs) from the included studies and performed meta-analyses on overall survival and either disease-free survival (DFS) or disease-free recurrence. Meanwhile, we compared the occurrence of bone marrow micrometastasis among different pathological types and different stages of disease.

RESULTS

Eleven studies with a cumulative sample size of 2159 patients were included in our analysis. Our meta-analyses revealed that the occurrence of bone marrow micrometastasis was not related to patient pathological types and stages in cancers ranging from adenocarcinoma and squamous cell carcinoma [relative risk (RR): 0.92; 95% CI: 0.78-1.08; P = 0.29], stages I and II (RR: 0.88; 95% CI: 0.67-1.17; P = 0. 39), stages II and III (RR: 0.98; 95% CI: 0.73-1.31; P = 0.89) and stages I and III (RR: 0.84; 95% CI: 0.68-1.05; P = 0.13). However, molecular tumour cell detection within the bone marrow was associated with both poor OS (HR: 1.84; 95% CI: 1.41-2.40; P < 0.00001) and poor DFS (HR: 1.75; 95% CI: 1.18-2.60; P = 0.005). Our subgroup analyses indicated that the presence of bone marrow micrometastasis was not a significant prognostic factor with respect to DFS at stage I (HR: 2.35; 95% CI: 0.67-8.25; P = 0.18).

CONCLUSIONS

The molecular detection of isolated tumour cell in the bone marrow is associated with both poor survival and an increased rate of recurrence in patients with node-negative NSCLC; this approach may result in the development of a new metastatic cascade concept and the development of novel approaches to cancer therapy.

Identification and characterization of unique tumoricidal genes in rat umbilical cord matrix stem cells

Rat umbilical cord matrix stem cells (UCMSC) have been shown to exhibit a remarkable ability to control rat mammary adenocarcinoma (Mat B III) cell proliferation both in vivo and in vitro. To study the underlying mechanisms and genes involved in Mat B III growth attenuation, total RNA was extracted from the naive rat UCMSC alone and those cocultured with Mat B III in Transwell culture dishes. Gene expression profiles of naive rat UCMSC alone and those cocultured with Mat B III cells were investigated by microarray analysis using an Illumina RatRef-12 Expression BeadChip. The comparison of gene expression profiles between untreated and cocultured rat UCMSC identified five upregulated candidate genes (follistatin (FST), sulfatase1 (SULF-1), glucose phosphate isomerase (GPI), HtrA serine peptidase (HTRA1), and adipocyte differentiation-related protein (ADRP)) and two downregulated candidate genes (transforming growth factor, beta-induced, 68 kDa (TGFβI) and podoplanin (PDPN)) based upon the following screening criteria: (1) expression of the candidate genes should show at least a 1.5-fold change in rat UCMSC cocultured with Mat B III cells; (2) candidate genes encode secretory proteins; and (3) they encode cell growth-related proteins. Following confirmation of gene expression by real-time PCR, ADRP, SULF-1 and GPI were selected for further analysis. Addition of specific neutralizing antibodies against these three gene products or addition of gene-specific siRNA's individually in cocultures of 1:20 rat UCMSC:Mat B III cells significantly increased cell proliferation, implying that these gene products are produced under the cocultured condition and functionally attenuate cell growth. Immunoprecipitation followed by Western blot analysis demonstrated that these proteins are indeed secreted into the culture medium. Individual overexpression of these three genes in rat UCMSC significantly enhanced UCMSC-dependent inhibition of cell proliferation in coculture. These results suggest that ADRP, SULF-1 and GPI act as tumor suppressor genes, and these genes might be involved in rat UCMSC-dependent growth attenuation of rat mammary tumors.

Cytotherapy with naive rat umbilical cord matrix stem cells significantly attenuates growth of murine pancreatic cancer cells and increases survival in syngeneic mice

BACKGROUND AIMS

Pancreatic cancer, sometimes called a 'silent killer', is one of the most aggressive human malignancies, with a very poor prognosis. It is the fourth leading cause of cancer-related morbidity and mortality in the USA.

METHODS

A mouse peritoneal model was used to test the ability of unengineered rat umbilical cord matrix-derived stem cells (UCMSC) to control growth of pancreatic cancer. In vivo results were supported by various in vitro assays, such as 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), direct cell count, [3H]thymidine uptake and soft agar colony assays.

RESULTS

Co-culture of rat UCMSC with PAN02 murine pancreatic carcinoma cells (UCMSC:PAN02, 1:6 and 1:3) caused G0/G1 arrest and significantly attenuated the proliferation of PAN02 tumor cells, as monitored by MTT assay, direct cell counts and [3H]thymidine uptake assay. Rat UCMSC also significantly reduced PAN02 colony size and number, as measured by soft agar colony assay. The in vivo mouse studies showed that rat UCMSC treatment significantly decreased the peritoneal PAN02 tumor burden 3 weeks after tumor transplantation and increased mouse survival time. Histologic study revealed that intraperitoneally administered rat UCMSC survived for at least 3 weeks, and the majority were found near or inside the tumor.

CONCLUSIONS

These results indicate that naive rat UCMSC alone remarkably attenuate the growth of pancreatic carcinoma cells in vitro and in a mouse peritoneal model. This implies that UCMSC could be a potential tool for targeted cytotherapy for pancreatic cancer.

Naïve human umbilical cord matrix derived stem cells significantly attenuate growth of human breast cancer cells in vitro and in vivo

The effect of un-engineered (naïve) human umbilical cord matrix stem cells (hUCMSC) on the metastatic growth of MDA 231 xenografts in SCID mouse lung was examined. Three weekly IV injections of 5x10(5) hUCMSC significantly attenuated MDA 231 tumor growth as compared to the saline-injected control. IV injected hUCMSC were detected only within tumors or in close proximity to the tumors. This in vivo result was corroborated by multiple in vitro studies such as colony assay in soft agar and [(3)H]-thymidine uptake. These results suggest that naïve hUCMSC may be a useful tool for cancer cytotherapy.

Increased immunogenicity of colon cancer cells by selective depletion of cytochrome C

We and others have previously reported in an in vivo rat colon cancer cell model that cell death precedes and is necessary for the development of a specific antitumoral immune response. To sensitize colon cancer cells to death, we depleted cytochrome c by stable transfection with an antisense construct. Cytochrome c depletion sensitizes human and rat colon cancer cells to a nonapoptotic, nonautophagic death induced by various stimuli. This increased sensitization to a necrosis-like cell death may be related to a decrease in cellular ATP levels and an increase in reactive oxygen species production caused by cytochrome c depletion. In vivo, depletion of cytochrome c decreases the tumorigenicity of colon cancer cells in syngeneic rats without influencing their growth in immune-deficient animals. Furthermore, decreased expression of cytochrome c in tumor cells facilitates in vivo "necrotic" cell death and the induction of a specific immune response. These results delineate a novel strategy to sensitize colon cancer cells to chemotherapy and to increase their immunogenicity in immuno-competent hosts.