Comparative abilities of athymic nude mice and severe combined immune deficient (SCID) mice to accept transplants of induced rat mammary carcinomas: enhanced transplantation efficiency of those rat mammary carcinomas that have elevated expression of neu oncogene

Interleukin-33 increases the sensitivity of multiple myeloma cells to the proteasome inhibitor bortezomib through reactive oxygen species-mediated inhibition of nuclear factor kappa-B signal and stemness properties

The proteasome inhibitor bortezomib (BTZ) is the first-line therapy for multiple myeloma (MM). BTZ resistance largely limits its clinical application in MM. Interleukin-33 (IL-33) exerts antitumor effects through various mechanisms, including enhancing antitumor immunity and promoting the apoptosis of cancer cells. Here, the synergistic anti-MM effect of IL-33 and BTZ was verified, and the underlying mechanisms were elucidated. Bioinformatic analysis indicated that IL-33 expression levels were downregulated in MM, and that BTZ-treated MM patients with high IL-33 levels had better prognosis than those with low IL-33 levels. Moreover, the patients with high IL-33 levels had a better treatment response to BTZ. Further immune analysis suggested that IL-33 can enhance the anti-MM immunity. IL-33 and BTZ synergistically inhibited proliferation and induced apoptosis of MM cells, which was mediated by the excessive accumulation of cellular reactive oxygen species (ROS). Furthermore, increased ROS hindered the nuclear translocation of NF-κB-p65, thereby decreasing the transcription of target stemness-related genes (SOX2, MYC, and OCT3/4). These effects induced by the combination therapy could be reversed by eliminating ROS by N-acetylcysteine. In conclusion, our results indicated that IL-33 enhanced the sensitivity of MM to BTZ through ROS-mediated inhibition of nuclear factor kappa-B (NF-κB) signal and stemness properties.

Comparison of Allotransplantation of Fresh and Vitrified Mouse Ovaries to The Testicular Tissue under Influence of The Static Magnetic Field

Objective

The aim of this study was to investigate the effects of static magnetic field (SMF) during transplantation of the ovarian tissue into the testis.

Materials and Methods

In this experimental study, ovaries of 6- to 8-week-old female Naval Medical Research Institute (NMRI) mice were randomly divided into four groups: i. Fresh ovaries were immediately transplanted into the testicular tissue (FOT group), ii. Fresh ovaries were exposed to the SMF for 10 minutes and then transplanted into the testicular tissue (FOT+group), iii. Vitrified-warmed ovaries were transplanted into the testicular tissue (VOT group), and iv. Vitrified-warmed ovaries were transplanted into the testicular tissue and the transplantation site was then exposed to the SMF for 10 minutes (VOT+group).

Results

The lowest percentages of morphologically dead primordial follicles and the highest percentages of morphologically intact primordial follicles were seen in the FOT+ group (4.11% ± 2.88 and 41.26% ± 0.54, respectively). Although the lowest significant percentage of maturation, embryonic development and fertility was observed in the VOT group as compared to the other groups, the difference in the fertility rate was not significant between the VOT and VOT+groups. Estrogen and progesterone concentrations were significantly higher in the FOT+group than those of the control mice.

Conclusion

It is concluded that, exposure of the vitrified-warmed ovaries to SMF retains the structure of the graft similar to that of fresh ovaries.

Mouse and human pluripotent stem cells and the means of their myogenic differentiation

Pluripotent stem cells, such as embryonic stem cells and induced pluripotent stem cells, are an important tool in the studies focusing at the differentiation of various cell types, including skeletal myoblasts. They are also considered as a source of the cells that due to their pluripotent character and availability could be turned into any required tissue and then used in future in regenerative medicine. However, the methods of the derivation of some of cell types from pluripotent cells still need to be perfected. This chapter summarizes the history and current advancements in the derivation and testing of pluripotent stem cells-derived skeletal myoblasts. It focuses at the in vitro methods allowing the differentiation of stem cells grown in monolayer or propagated as embryoid bodies, and also at in vivo tests allowing the verification of the functionality of obtained skeletal myoblasts.

Animal models of breast cancer for the study of pathogenesis and therapeutic insights

Activation of oncogenes and inactivation of tumour suppressor genes are common events during breast cancer initiation and progression and often determine treatment responsiveness. Indeed, these events need to be recreated in in vitro systems and in mouse cancer models in order to unravel the molecular mechanisms involved in breast cancer initiation and metastasis and assess their possible impact on responses to anticancer drugs. Optical-based imaging models are used to investigate and to follow important tumour progression processes. Moreover, the development of novel anticancer strategies requires more sensitive and less invasive methods to detect and monitor in vivo drug responses in breast cancer models. This review highlights some of the current strategies for modelling breast cancer in vitro and in the mouse, in order to answer biological or translational questions about human breast malignancies.

Differentiation of human embryonic stem cells after transplantation in immune-deficient mice

Our current knowledge of how human tissues grow and develop is limited. We need to increase our understanding of tissue formation if we are to fully realize the potential of stem cells as a source of material for research into health and disease and possible therapeutic applications. Transplanted pluripotent human embryonic stem cells (hESCs) provide a potential system to model and investigate cell differentiation in humans. hESCs transplanted into immune-deficient mice form complex teratomas consisting of a range of differentiated somatic tissues, some of which appear highly organized and resemble structures normally identified in the embryo and adult. Analysis of such tumors may provide a unique opportunity to study organogenesis and lead to novel approaches in bioengineering and the growth of functioning structures composed of a range of alternative cell types. However, little has been done to characterize the developmental potential of hESCs after transplantation. This concise review presents evidence for the ability of hESCs to differentiate in vivo and highlights some of the prominent questions that need to be addressed if transplantation is to be used as a research tool to study hESC differentiation.

Overexpression of Bcl-xL in human breast cancer cells enhances organ-selective lymph node metastasis

Lymph node metastasis are the first prognostic factor in breast cancer diagnosis and an early event in metastatic spread. To assess the role of anti-apoptotic proteins in lymph node metastatic progression of human breast cancer cells we analyzed the metastatic activity of MDA-MB-435 cells transfected with the Bcl-xL gene, after orthotopic inoculation in Nude Balb/c and in SCID mice. The luciferase gene was introduced by permanent transfection in the 435/Bcl-xL and 435/Neo cells and used as a tumor marker to measure the number of tumor cells lodged in lymph nodes. We found that 435/Bcl-xL tumor cells had enhanced organ-specific metastatic activity, preferentially lodging in peripheral lymph nodes, where at 45 days post-implantation we found 7 x 10(6) +/- 6 x 10(6) 435/Bcl-xL.luc and 2 +/- 1.1 435/Neo.luc luciferase tagged tumor cell equivalents (TCEs). Metastases were abrogated in mice in which orthotopic tumors were induced with 435/Bcl-xL-antisense cells. Additionally, in vitro experiments show that in 435 cells Bcl-xL-antisense can override the emergence of resistance to apoptosis induced by TNF- alpha and TGF- beta in cells overexpressing Bcl-xL, increasing also adhesion to extracellular matrix proteins. These results point to the relevance of Bcl-xL overexpression inducing lymph node metastasis of breast cancer cells, and to the value of this gene as a target for therapy in order to prevent metastasis.

BXD recombinant inbred mice represent a novel T cell-mediated immune response tumor model

To develop a better animal model for studying the effects of the host environment in neoplasia, we injected various genetically well-characterized H-2(d) RI strains of BXD mice with syngeneic breast cancer cells (TS/A) and monitored the growth of tumors over time. There was a marked difference in the growth of the implanted breast cancer cells among the 14 BXD RI strains, with 4 patterns of tumor development being observed: in type I, the implanted tumor cells grew rapidly in the first 2 weeks, necrosis of the tumors was observed and metastases to the intestinal lymph nodes and pancreas was observed, causing death; in type II, the implanted tumor cells grew slowly and attained a size after day 50 that required killing the animal, with tumor necrosis being rare and metastases absent; in type III, the implanted tumor cells grew initially but underwent a slow decline after 4 weeks; and in type IV, the implanted tumor cells failed to develop. Apoptosis of the implanted tumor cells was responsible for the regression of tumor nodules. The T-cell immune response minimized tumor development in types III and IV since T-cell depletion of the BXD RI mice resulted in aggressively growing tumors in these strains.

Genetic alteration of chromosome 8 is a common feature of human mammary epithelial cell lines transformed in vitro with benzo[a]pyrene

While some epidemiological risk factors for breast cancer have been identified, the environmental factors responsible for transformation of mammary epithelial cells are not clear. We have exposed the spontaneously immortalized human mammary epithelial cell line MCF-10A to benzo[a]pyrene and selected transformed clones based on a loss of contact inhibition and anchorage-dependent growth. Cytogenetic studies showed that each of the transformed sublines possess an isochromosome 8q aberration. The c-Myc proto-oncogene, which is positioned at 8q24, was analyzed for changes in expression. Both c-Myc mRNA and protein levels were increased in the transformed clones relative to the parental cells. The transformed clones were not able to grow as tumors in vivo when injected into nude or SCID mice. To determine whether the involvement of chromosome 8 in BP-induced mutagenesis was a reproducible event, transformed clones were selected from three additional independently treated sets of BP-exposed MCF-10A cultures and analyzed by spectral karyotyping (SKY). These transformed sublines also harbored the isochromosome 8q abnormality. Data from this model show that benzo[a]pyrene, a ubiquitous procarcinogen, can induce selectable morphologic changes in a human mammary epithelial cell line, and that these transformed cells possess chromosomal aberrations frequently found in human breast tumors.

Estrogen mitogenic action. I. Demonstration of estrogen-dependent MTW9/PL2 carcinogen-induced rat mammary tumor cell growth in serum-supplemented culture and technical implications

The MTW9/PL cell line was established by our laboratory in culture from the carcinogen-induced hormone-responsive MT-W9A rat mammary tumor of a Wistar-Furth (W/Fu) rat. This tumor formed estrogen, androgen, and progesterone responsive tumors in W/Fu rats (Sirbasku, D. A., Cancer Res. 38:1154-1165; 1978). It was later used to derive the MTW9/PL2 cell population which was also estrogen-responsive in vivo (Danielpour, D., et al., In Vitro Cell. Dev. Biol. 24:42-52; 1988). In the study presented here, we describe serum-supplemented culture conditions in which the MTW9/PL2 cells demonstrate > or = 80-fold steroid hormone growth responses. All sera used were steroid hormone-depleted by charcoal-dextran treatment at 34 degrees C. The studies were done with horse serum as well as serum from other mammalian species. The growth of the MTW9/PL2 cells was biphasic in response to hormone-depleted serum. Concentrations of < or = 5% (v/v) promoted optimum growth. Above this concentration, serum was inhibitory. Concentrations > or = 40% (v/v) inhibited growth altogether. Addition of 1.0 x 10(-13)-1.0 x 10(-8) M 17beta,-estradiol (E2) reversed the inhibition completely. At 1.0 x 10(-8) M, estrone, estriol and diethylstilbestrol promoted growth as well as E2. Testosterone and dihydrotestosterone promoted growth only at > or = 10(-7) M. Progesterone was effective only at > or = 10(-6) M. Cortisol was ineffective. Labeled-hormone-binding analysis and Western immunoblotting documented that MTW9/PL2 cells had estrogen and progesterone receptors but not androgen or cortisol receptors. Estrogen treatment of MTW9/PL2 cells induced a concentration and time dependent increase in progesterone receptors. We conclude (1) the MTW9/PL2 population is the first highly steroid hormone-responsive rat mammary tumor cell line to be established in culture from a carcinogen-induced tumor, and (2) sera from a number of species including horse, rat and human contain an inhibitor which mediates estrogen sensitive MTW9/PL2 cell growth in culture.

Hormone dependent and independent mammary tumor development form N-methyl-N-nitrosourea-treated rat mammary epithelial cell xenografts in the nude mouse: multiple pathways and H-ras activation

A nude mouse mammary fat pad xenograft system was developed to examine hormone dependent and independent mammary tumorigenesis and progression from N-methyl-N-nitrosourea (MNU)-induced hyperplastic lesions. Ninety-one percent of transplanted mammary tumors grew, with an orthotopic preference, and maintained their hormone dependence, histopathology, and H-ras mutation frequency. Grafted mammary epithelial cells, from MNU-treated rats, developed normal; and hyperplastic outgrowths, representative of those found in the rat mammary gland after MNU-treatment. Hyperplasias developed into neoplasias that were both hormone dependent and independent. We demonstrate that hormone independent tumors can develop directly either from lobuloalveolar or ductal hyperplasias or from hormone dependent tumors. H-ras mutation was detected in mammary preneoplasias (4 lines) before they developed into tumors and was associated with an elevated tumorigenic potential. Our observations suggest that there are multiple histopathogenic pathways in the development and progression to hormone independent rat mammary tumors.

Human breast cancer cell line xenografts as models of breast cancer. The immunobiologies of recipient mice and the characteristics of several tumorigenic cell lines

The ability to maintain and study human tissues in an in vivo environment has proved to be a valuable tool in breast cancer research for several decades. The most widely studied tissues have been xenografts of established human breast cancer cell lines into athymic nude mice. Human breast tumor xenografts provide the opportunity to study various important interactions between the tumor and host tissues, including endocrinologic, immunologic, and tumor-stroma interactions. The nude mouse is not the only immune-deficient recipient system in which to study xenografts. Additional single and combined mutant strains have been used successfully, including mice homozygous for the severe combined immune deficiency mutation (scid), both the beige (bg) and nude (nu) mutations in combination (bg/nu), and mice bearing the combined bg/nu/xid mutations. The differing immunobiologies are discussed, with particular reference to the immunobiology of breast cancer, as are the characteristics of several of the more frequently utilized breast cancer xenografts and cell lines. The ability of several endocrine treatments to modulate effectors of cell mediated immunity, e.g., estrogens and antiestrogens, and the effect of site of inoculation on tumor take and metastasis, also are described.

Induction of ductal carcinomas by intraductal administration of 7,12-dimethylbenz(a)anthracene in Wistar rats

Postpartum Wistar inbred rats (weaned on the 9th puerperal day) were injected intraductally in one mammary gland with 7,12-dimethylbenze (a) anthracene (DMBA) to selectively induce ductal carcinoma. The incidence of ductal hyperplasia increased with time until it peaked at 7 weeks (12/13 animals) and then decreased. Ductal carcinoma first developed at 9 weeks in 3/12 (2 non-invasive and 1 invasive lesion) and the incidence increased with time until invasive ductal tumors were observed in 9/11 at 20 weeks. Tumors developed only in the DMBA-treated mammary glands and no systemic effects of the carcinogen were observed. Degeneration and detachment of epithelioglandular cells were seen here and there in the ducts and terminal ducts, and epithelioglandular cells proliferated in terminal duct until 2 weeks. Residual trace DMBA powder was detected in terminal ducts and the epithelioglandular layer until 7 weeks. This trace DMBA was considered to be the cause of the development of atypical epithelial cells, inducing ductal carcinomas.

Infrequent transforming mutations in the transmembrane domain of the neu oncogene in spontaneous rat schwannomas

Ethylnitrosourea (ENU) given transplacentally to rats induces schwannomas of the cranial, spinal, and peripheral nerves, with a high frequency of mutations in the neu proto-oncogene. To establish the requirement for such mutations in tumorigenesis of the Schwann cell, spontaneous schwannomas from BD-VI rats were evaluated for transforming mutations in the transmembrane domain of the protein encoded by the neu proto-oncogene. While all five schwannomas induced transplacentally with ENU were shown to contain T-->A transversions in base 2012 of neu by selective oligonucleotide hybridization and dideoxy sequencing of polymerase chain reaction-amplified products from paraffin sections, only one of nine spontaneous schwannomas from untreated rats had the same mutation. Examination of tumors for mutations in codon 12 of Ki-ras revealed normal alleles. Therefore, the high frequency of mutations in neu in ENU-induced tumors may be directly attributable to the carcinogen or to the period of development at which exposure occurred, and transforming mutations of the transmembrane domain of neu are not required for tumorigenesis of the Schwann cell.