Trask loss enhances tumorigenic growth by liberating integrin signaling and growth factor receptor cross-talk in unanchored cells.

The cell surface glycoprotein Trask/CDCP1 is phosphorylated during anchorage loss in epithelial cells in which it inhibits integrin clustering, outside-in signaling, and cell adhesion. Its role in cancer has been difficult to understand, because of the lack of a discernible pattern in its various alterations in cancer cells. To address this issue, we generated mice lacking Trask function.

The β1-integrin-p-FAK-p130Cas-DOCK180-RhoA-vinculin is a novel regulatory protein complex at the apical ectoplasmic specialization in adult rat testes.

During spermatogenesis, step 1 spermatids (round spermatids) derive from spermatocytes following meiosis I and II at stage XIV of the epithelial cycle begin a series of morphological transformation and differentiation via 19 steps in rats to form spermatozoa. This process is known as spermiogenesis, which is marked by condensation of the genetic material in the spermatid head, formation of the acrosome and elongation of the tail. Since developing spermatids are lacking the robust protein synthesis and transcriptional activity, the cellular, molecular and morphological changes associated with spermiogenesis rely on the Sertoli cell in the seminiferous epithelium via desmosome and gap junction between Sertoli cells and step 1-7 spermatids.

Phosphorylation of Trask by Src kinases inhibits integrin clustering and functions in exclusion with focal adhesion signaling.

Trask is a recently described transmembrane substrate of Src kinases whose expression and phosphorylation has been correlated with the biology of some cancers. Little is known about the molecular functions of Trask, although its phosphorylation has been associated with cell adhesion. We have studied the effects of Trask phosphorylation on cell adhesion, integrin activation, clustering, and focal adhesion signaling.

Improved tumor vascular function following high-dose epidermal growth factor receptor tyrosine kinase inhibitor therapy.

Purpose: To determine if inhibitors of the human growth factor receptor (HER) family can be used to enhance tumor vascular permeability and perfusion and optimize the efficacy of cytotoxic chemotherapeutics. Poor tumor vascular function limits the delivery and efficacy of cancer chemotherapeutics and HER family tyrosine kinases mediate tumor-endothelial signaling in both of these compartments.

Materials And Methods: BT474 human breast cancer tumors were established in mice and the biologic effects of the HER tyrosine kinase inhibitor (TKI) gefitinib on tumor vascular function was determined by dynamic contrast-enhanced MRI (DCE-MRI), and on tumor vascular architecture and perfusion by immunofluorescence microscopy.

Dynamin II interacts with the cadherin- and occludin-based protein complexes at the blood-testis barrier in adult rat testes.

In adult rat testes, blood-testis barrier (BTB) restructuring facilitates the migration of preleptotene spermatocytes from the basal to the adluminal compartment that occurs at stage VIII of the epithelial cycle. Structural proteins at the BTB must utilize an efficient mechanism (e.g.

Targeted and reversible disruption of the blood-testis barrier by an FSH mutant-occludin peptide conjugate.

The blood-testis barrier (BTB) is one of the tightest blood-tissue barriers in mammals. As such, it poses a challenge to deliver any drugs to the seminiferous epithelium of the testis, such as a nonhormonal male contraceptive. To circumvent this problem, a genetically engineered follicle-stimulating hormone (FSH) mutant protein was produced in Spodoptera furgiperda (Sf)-9 insect cells to serve as a testis-specific carrier.

The blood-testis barrier: its biology, regulation, and physiological role in spermatogenesis.

The blood-testis barrier (BTB) in mammals, such as rats, is composed of the tight junction (TJ), the basal ectoplasmic specialization (basal ES), the basal tubulobulbar complex (basal TBC) (both are testis-specific actin-based adherens junction [AJ] types), and the desmosome-like junction that are present side-by-side in the seminiferous epithelium. The BTB physically divides the seminiferous epithelium into basal and apical (or adluminal) compartments, and is pivotal to spermatogenesis. Besides its function as an immunological barrier to segregate the postmeiotic germ-cell antigens from the systemic circulation, it creates a unique microenvironment for germ-cell development and confers cell polarity.

AF-2364 [1-(2,4-dichlorobenzyl)-1H-indazole-3-carbohydrazide] is a potential male contraceptive: a review of recent data.

Earlier studies have shown that 1-(2,4-dichlorobenzyl)-1H-indazole-3-carbohydrazide (AF-2364) is a potential male contraceptive when administered orally to adult Sprague-Dawley rats. This compound induces reversible germ cell loss from the seminiferous epithelium by disrupting cell adhesion function between Sertoli and germ cells, in particular, elongating/elongate/round spermatids and spermatocytes but not spermatogonia. Thus, this event is accompanied by a transient loss of fertility in treated rats.

Mitogen-activated protein kinases, adherens junction dynamics, and spermatogenesis: a review of recent data.

Mitogen-activated protein kinases (MAPKs) are important regulators of many cellular processes. In mammalian testes, these kinases are involved in controlling cell division, differentiation, survival and death, and are therefore critical to spermatogenesis. Recent studies have also illustrated their involvement in junction restructuring in the seminiferous epithelium, especially at the ectoplasmic specialization (ES), a testis-specific adherens junction (AJ) type.

Disruption of Sertoli-germ cell adhesion function in the seminiferous epithelium of the rat testis can be limited to adherens junctions without affecting the blood-testis barrier integrity: an in vivo study using an androgen suppression model.

During spermatogenesis, both adherens junctions (AJ) (such as ectoplasmic specialization (ES), a testis-specific AJ type at the Sertoli cell-spermatid interface (apical ES) or Sertoli-Sertoli cell interface (basal ES) in the apical compartment and BTB, respectively) and tight junctions (TJ) undergo extensive restructuring to permit germ cells to move across the blood-testis barrier (BTB) as well as the seminiferous epithelium from the basal compartment to the luminal edge to permit fully developed spermatids (spermatozoa) to be sloughed at spermiation. However, the integrity of the BTB cannot be compromised throughout spermatogenesis so that postmeiotic germ cell-specific antigens can be sequestered from the systemic circulation at all times. We thus hypothesize that AJ disruption in the seminiferous epithelium unlike other epithelia, can occur without compromising the BTB-barrier, even though these junctions, namely TJ and basal ES, co-exist side-by-side in the BTB.

Blood-testis barrier dynamics are regulated by {alpha}2-macroglobulin via the c-Jun N-terminal protein kinase pathway.

The blood-testis barrier (BTB), in contrast to the blood-brain and blood-retina barriers, is composed of coexisting tight junctions, gap junctions, and basal ectoplasmic specializations, a testis-specific type of adherens junction. Recent studies showed that BTB restructuring that facilitates germ cell migration during spermatogenesis involves proteolysis, an event that is usually restricted to the cell-matrix interface in other epithelia. For instance, a surge in alpha(2)-macroglobulin (alpha(2)-MG), a protease inhibitor produced by Sertoli cells, was detected at the Sertoli-Sertoli and Sertoli-germ cell interface in the epithelium during cadmium chloride-induced BTB disruption in adult rats.

Regulation of ectoplasmic specialization dynamics in the seminiferous epithelium by focal adhesion-associated proteins in testosterone-suppressed rat testes.

Apical ectoplasmic specialization (ES) is a unique testis-specific cell-cell actin-based adherens junction type restricted to the Sertoli-round/elongating/elongate spermatid interface in the seminiferous epithelium. An endogenous testosterone (T) suppression model was used to study the regulation of apical ES dynamics in the testis. By providing sustained releases of T and estradiol using subdermal implants in rats, this treatment reduced endogenous testicular T level.

TGF-beta3 regulates the blood-testis barrier dynamics via the p38 mitogen activated protein (MAP) kinase pathway: an in vivo study.

Recent studies using Sertoli cells cultured in vitro to permit tight junction (TJ) assembly have shown that TJ dynamics are regulated, at least in part, by TGF-beta3 via the p38 mitogen activated protein (MAP) kinase pathway. This in turn regulates the production of occludin, a TJ-integral membrane protein, by Sertoli cells. Yet it is not known if this pathways is used by Sertoli cells to regulate the blood-testis barrier (BTB) function in vivo.