A seed or soil problem in early endometriosis: stromal cell origin drives cellular invasion and coupling over mesothelial cell origin.

OBJECTIVE: To study the role of the mesothelial cells in early endometriosis lesion formation by assessing in vitro cell-to-cell communication and invasion of endometrial cells across a mesothelial cell monolayer, with both cell types derived from both patients with endometriosis and control patients. DESIGN: Laboratory-based experimental study. SETTING: University hospital and laboratory. PATIENT(S): Consenting reproductive-age women who underwent laparoscopy for gynecologic reasons and were confirmed to have either endometriosis with pathology tissue diagnosis (n = 8) or no endometriosis n = 8) at the time of surgery. INTERVENTION(S): Primary stromal cells cultured from endometrial pipelle biopsies and primary mesothelial cells cultured from peritoneal explants were used in transmesothelial invasion assays and gap junction coupling assays. MAIN OUTCOME MEASURE(S): Comparison of potential for lesion formation, using in vitro models, of both primary endometrial and mesothelial cells from patients with endometriosis and control patients, establishing the former as the primary disease driver. RESULT(S): When comparing mesothelial cells from control patients with those from patients with endometriosis, there was no significant difference in the amount of stromal cell invasion across either barrier. In contrast, when comparing stromal cell origin, the amount of invasion by endometriosis stromal cells was greater than control stromal cells regardless of whether the mesothelial cell monolayer was derived from patients with the disease or control patients. Additionally, primary mesothelial cells induced more gap junction coupling, a requirement for invasion, in stromal cells from patients with endometriosis than control patients, again independent of mesothelial origin. The notable exception was mesothelial cells derived from endometriotic lesion-affected areas that showed depressed ability to support invasion. CONCLUSION(S): Although both endometrial and mesothelial cells need to function for establishment of endometriosis lesions, the endometrium seems to be the key player, serving as an ideal target for diagnostic strategies and therapeutic intervention. While this notion is consistent with previous studies, to our knowledge, we are the first to directly test both primary mesothelial and endometrial cells from patients with endometriosis and control patients to compare propensities for mesothelial invasion.

Antibody-activation of connexin hemichannels in bone osteocytes with ATP release suppresses breast cancer and osteosarcoma malignancy.

Bone tissue represents the most frequent site of cancer metastasis. We developed a hemichannel-activating antibody, Cx43-M2. Cx43-M2, directly targeting osteocytes in situ, activates osteocytic hemichannels and elevates extracellular ATP, thereby inhibiting the growth and migration of cultured breast and osteosarcoma cancer cells. Cx43-M2 significantly decreases breast cancer metastasis, osteosarcoma growth, and osteolytic activity, while improving survival rates in mice. The antibody's inhibition of breast cancer and osteosarcoma is dose dependent in both mouse and human cancer metastatic models. Furthermore, Cx43-M2 enhances anti-tumor immunity by increasing the population and activation of tumor-infiltrating immune-promoting effector T lymphocytes, while reducing immune-suppressive regulatory T cells. Our results suggest that the Cx43-M2 antibody, by activating Cx43 hemichannels and facilitating ATP release and purinergic signaling, transforms the cancer microenvironment from a supportive to a suppressive state. Collectively, our study underscores the potential of Cx43-M2 as a therapeutic for treating breast cancer bone metastasis and osteosarcoma.

Co-targeting ALK and EGFR parallel signaling in oral squamous cell carcinoma.

Squamous cell carcinoma (SCC) comprises 90% of all head and neck cancers and has a poor survival rate due to late-stage disease that is refractive to traditional therapies. Epidermal growth factor receptor (EGFR) is over-expressed in greater than 80% of head and neck SCC (HNSCC). However, EGFR targeted therapies yielded little to no efficacy in clinical trials. This study investigated the efficacy of co-targeting EGFR and the anaplastic lymphoma kinase (ALK) whose promoter is hypomethylated in late-stage oral SCC (OSCC). We observed increased ALK activity in late-stage human OSCC tumors and invasive OSCC cell lines. We also found that while ALK inhibition alone had little effect on proliferation, co-targeting ALK and EGFR significantly reduced OSCC cell proliferation in vitro. Further analysis showed significant efficacy of combined treatment in HSC3-derived xenografts resulting in a 30% decrease in tumor volumes by 14days (p<0.001). Western blot analysis showed that co-targeting ALK and EGFR significantly reduced EGFR phosphorylation (Y1148) in HSC3 cells but not Cal27 cells. ALK and EGFR downstream signaling interactions are also demonstrated by Western blot analysis in which lone EGFR and ALK inhibitors attenuated AKT activity whereas co-targeting ALK and EGFR completely abolished AKT activation. No effects were observed on ERK1/2 activation. STAT3 activity was significantly induced by lone ALK inhibition in HSC3 cells and to a lower extent in Cal27 cells. Together, these data illustrate that ALK inhibitors enhance anti-tumor activity of EGFR inhibitors in susceptible tumors that display increased ALK expression, most likely through abolition of AKT activation.

Modulation of telomeres in alternative lengthening of telomeres type I like human cells by the expression of werner protein and telomerase.

The alternative lengthening of telomeres (ALT) is a recombination-based mechanism of telomere maintenance activated in 5-20% of human cancers. In Saccharomyces cerevisiae, survivors that arise after inactivation of telomerase can be classified as type I or type II ALT. In type I, telomeres have a tandem array structure, with each subunit consisting of a subtelomeric Y' element and short telomere sequence. Telomeres in type II have only long telomere repeats and require Sgs1, the S. cerevisiae RecQ family helicase. We previously described the first human ALT cell line, AG11395, that has a telomere structure similar to type I ALT yeast cells. This cell line lacks the activity of the Werner syndrome protein, a human RecQ helicase. The telomeres in this cell line consist of tandem repeats containing SV40 DNA, including the origin of replication, and telomere sequence. We investigated the role of the SV40 origin of replication and the effects of Werner protein and telomerase on telomere structure and maintenance in AG11395 cells. We report that the expression of Werner protein facilitates the transition in human cells of ALT type I like telomeres to type II like telomeres in some aspects. These findings have implications for the diagnosis and treatment of cancer.