Integrin α-3 ß-1's central role in breast cancer, melanoma and glioblastoma cell aggregation revealed by antibodies with blocking activity.

Breast cancer, melanoma and glioblastoma cells undergo cell-mediated aggregation and aggregate coalescence in a transparent 3D Matrigel environment. Cells from normal tissue and non-tumorigenic cell lines do not exhibit these behaviors. Here, 266 monoclonal antibodies (mAbs) demonstrated to interact with a wide variety of membrane, secreted and matrix proteins, have been screened for their capacity to block these tumorigenic cell-specific behaviors in a 3D environment. Remarkably, only six of the 266 tested mAbs exhibited blocking activity, four targeting integrin ß-1, one targeting integrin α-3 and one targeting CD44. Colocalization of integrins ß-1 and α-3 in fixed cells and in live aggregates suggests that the integrin α-3 ß-1 dimer plays a central role in cancer cell aggregation in the 3D environment provided by Matrigel. Our results suggest that blocking by anti-integrin and anti-CD44 mAbs involves interference in cell-cell interactions.

Overexpressing TPTE2 (TPIP), a homolog of the human tumor suppressor gene PTEN, rescues the abnormal phenotype of the PTEN-/- mutant.

One possible approach to normalize mutant cells that are metastatic and tumorigenic, is to upregulate a functionally similar homolog of the mutated gene. Here we have explored this hypothesis by generating an overexpressor of TPTE2 (TPIP), a homolog of PTEN, in PTEN-/- mutants, the latter generated by targeted mutagenesis of a human epithelial cell line. Overexpression of TPTE2 normalized phenotypic changes associated with the PTEN mutation. The PTEN-/- -associated changes rescued by overexpressing TPTE2 included 1) accelerated wound healing in the presence or absence of added growth factors (GFs), 2) increased division rates on a 2D substrate in the presence of GFs, 3) adhesion and viability on a 2D substrate in the absence of GFs, 4) viability in a 3D Matrigel model in the absence of GFs and substrate adhesion 5) loss of apoptosis-associated annexin V cell surface binding sites. The results justify further exploration into the possibility that upregulating TPTE2 by a drug may reverse metastatic and tumorigenic phenotypes mediated in part by a mutation in PTEN. This strategy may also be applicable to other tumorigenic mutations in which a homolog to the mutated gene is present and can substitute functionally.

Prenatal Screening for and Prevalence of Hepatitis B Surface Antigen in Pregnant Women and Prevention of Transmission to Infants Born to Infected Mothers-Guam, 2014.

BACKGROUND: Perinatal transmission is the major mode of hepatitis B virus (HBV) transmission and drives HBV endemicity in the US territory of Guam. We assessed correlates of prenatal hepatitis B surface antigen (HBsAg) screening and HBsAg positivity among pregnant women and evaluated the care of infants of HBsAg-positive women. METHODS: Demographic and clinical data were abstracted from the maternal medical records of 966 randomly selected live infants born in 2014. Frequencies were calculated, and prevalence ratios (PRs) and 95% confidence intervals (CIs) were estimated using Poisson regression. RESULTS: Among the mothers of the 966 infants, 78.2% were Pacific Islanders, 56.9% were >25 years old (born before universal infant hepatitis B vaccination in Guam), 89.0% received prenatal care (PNC), 96.7% underwent prenatal HBsAg screening, and 2.0% were HBsAg positive. Approximately 15% of the women who did not have PNC were not screened for HBsAg. Receipt of PNC was associated with HBsAg screening (adjusted PR, 1.13 [95% CI, 1.04-1.23]), and HBsAg positivity was associated with a maternal age of >25 years (adjusted PR, 6.80 [95% CI, 1.32-35.08]). All 18 infants of the HBsAg-positive mothers received hepatitis B vaccine, and 17 (94.4%) received hepatitis B immunoglobulin. CONCLUSION: Although the prenatal HBsAg screening prevalence in this sample was high, the maternal HBsAg prevalence among women in this sample was more than 14 times and 2 times the prevalence among US-born Pacific Islander/Asian women and all women in the continental United States, respectively. Improving access to PNC, ensuring that all pregnant women in Guam (especially those born before universal hepatitis B vaccination) are screened for HBsAg, and adopting postexposure prophylaxis for infants of HBsAg-positive mothers as standard clinical practice are important for preventing perinatal HBV transmission and reducing HBV endemicity.

Screening for Syphilis and Other Sexually Transmitted Infections in Pregnant Women - Guam, 2014.

Prenatal screening and treatment for sexually transmitted infections (STIs) can prevent adverse perinatal outcomes. In Guam, the largest of the three U.S. territories in the Pacific, primary and secondary syphilis rates among women increased 473%, from 1.1 to 6.3 per 100,000 during 2009-2013 (1). In 2013, the first congenital syphilis case after no cases since 2008 was reported (1,2). Little is known about STI screening coverage and factors associated with inadequate screening among pregnant women in Guam. This study evaluated the prevalence of screening for syphilis, human immunodeficiency virus (HIV), chlamydia, and gonorrhea, and examined correlates of inadequate screening among pregnant women in Guam. Data came from the medical records of a randomly selected sample of mothers with live births in 2014 at a large public hospital. Bivariate analyses and multivariable models using Poisson regression were conducted to determine factors associated with inadequate screening for syphilis and other STIs. Although most (93.5%) women received syphilis screening during pregnancy, 26.8% were not screened sufficiently early to prevent adverse pregnancy outcomes. Many women were not screened for HIV infection (31.1%), chlamydia (25.3%), or gonorrhea (25.7%). Prenatal care and insurance were important factors affecting STI screening during pregnancy. Prenatal care providers play an important role in preventing congenital infections. Policies and programs increasing STI and HIV services for pregnant women and improved access to and use of prenatal care are essential for promoting healthy mothers and infants.

Hepatitis B Surface Antigen Screening Among Pregnant Women and Care of Infants of Hepatitis B Surface Antigen-Positive Mothers - Guam, 2014.

Hepatitis B virus (HBV) infection is endemic among adults in the U.S. territory of Guam (1,2). Perinatal HBV transmission, which occurs at birth from an infected mother to her newborn infant, is a major mode of HBV transmission and maintains HBV endemicity (3). Approximately 90% of HBV-infected infants will develop chronic HBV infection, and approximately 25% of those will die prematurely from liver failure or hepatocellular carcinoma (4,5). Since 1988, the Advisory Committee on Immunization Practices has recommended that all pregnant women be screened for hepatitis B surface antigen (HBsAg), an indicator of HBV infection, and that infants of women who screen positive (HBsAg-positive women) receive postexposure prophylaxis (PEP) (hepatitis B vaccine and hepatitis B immunoglobulin [HBIG]). When received within 12 hours of birth, PEP is 85%-95% effective in preventing perinatal HBV transmission (5,6). Hepatitis B vaccine provides long-term active immunity to HBV infection and HBIG provides short-term passive immunity to HBV infection until the infant responds to the vaccine (5). Hepatitis B vaccine was introduced into the routine universal infant vaccination schedule in Guam in 1988 (1).

Melanoma cells undergo aggressive coalescence in a 3D Matrigel model that is repressed by anti-CD44.

Using unique computer-assisted 3D reconstruction software, it was previously demonstrated that tumorigenic cell lines derived from breast tumors, when seeded in a 3D Matrigel model, grew as clonal aggregates which, after approximately 100 hours, underwent coalescence mediated by specialized cells, eventually forming a highly structured large spheroid. Non-tumorigenic cells did not undergo coalescence. Because histological sections of melanomas forming in patients suggest that melanoma cells migrate and coalesce to form tumors, we tested whether they also underwent coalescence in a 3D Matrigel model. Melanoma cells exiting fragments of three independent melanomas or from secondary cultures derived from them, and cells from the melanoma line HTB-66, all underwent coalescence mediated by specialized cells in the 3D model. Normal melanocytes did not. However, coalescence of melanoma cells differed from that of breast-derived tumorigenic cell lines in that they 1) coalesced immediately, 2) underwent coalescence as individual cells as well as aggregates, 3) underwent coalescence far faster and 4) ultimately formed long, flat, fenestrated aggregates that were extremely dynamic. A screen of 51 purified monoclonal antibodies (mAbs) targeting cell surface-associated molecules revealed that two mAbs, anti-beta 1 integrin/(CD29) and anti-CD44, blocked melanoma cell coalescence. They also blocked coalescence of tumorigenic cells derived from a breast tumor. These results add weight to the commonality of coalescence as a characteristic of tumorigenic cells, as well as the usefulness of the 3D Matrigel model and software for both investigating the mechanisms regulating tumorigenesis and screening for potential anti-tumorigenesis mAbs.