Enhanced levels of annexins in pancreatic carcinoma cells of Syrian hamsters and their intrapancreatic allografts.

Annexins are a family of calcium- and phospholipid-binding proteins related by amino acid sequence homology. Annexins I and II are substrates for protein tyrosine kinases. Recent investigations have revealed a possible involvement of annexins I and II in mitogenic signal transduction and cell proliferation. To investigate further the involvement of annexins in cell proliferation, we measured the levels of annexins I and II and the enzyme 3-phosphoglycerate kinase (PGK) (annexin II and PGK are components of the primer recognition protein complex) in normal Syrian hamster pancreas, three hamster pancreatic ductal carcinoma cell lines, and allografts of the three cell lines into hamster pancreas. All three carcinoma cell lines had 5-8-fold higher levels of annexin II compared to normal pancreas. An inverse relationship was seen between level of annexin II and the doubling time of the cell culture. In intrapancreatic allografts, annexin II levels were 3-6-fold higher than in normal pancreas. Annexin I levels were 2-3-fold higher in the allografts. Significant increases (5-6-fold) in specific activity of PGK were seen in all allografts examined. However, the level of PGK, as measured by immunoblotting, was not significantly altered. Immunohistochemical staining revealed heterogeneity in the reactivity of the antiannexin and anti-PGK antibodies with tumor cells. Strikingly, the reactivity and staining intensity were greater in the proliferating regions of the primary tumors and in the metastatic foci. Mitotic cells were either unstained or very weakly stained. We conclude from these findings that annexin II and PGK, as primer recognition proteins, may have a role in cell proliferation.     

c-Jun NH2-terminal kinase-induced proteasomal degradation of c-FLIPL/S and Bcl2 sensitize prostate cancer cells to Fas- and mitochondria-mediated apoptosis by tetrandrine

Tetrandrine, a constituent of Chinese herb Stephania tetrandra, causes cell death in prostate cancer, but the molecular mechanisms leading to apoptosis is not known. Here we demonstrated that tetrandrine selectively inhibits the growth of prostate cancer PC3 and DU145 cells compared to normal prostate epithelial PWR-1E cells. Tetrandrine-induced cell death in prostate cancer cells is caused by reactive oxygen species (ROS)-mediated activation of c-Jun NH₂-terminal kinase (JNK1/2). JNK1/2-mediated proteasomal degradation of c-FLIP_L/S and Bcl₂ proteins are key events in the sensitization of prostate cancer cells to Fas- and mitochondria-mediated apoptosis by tetrandrine. Tetrandrine-induced JNK1/2 activation caused the translocation of Bax to mitochondria by disrupting its association with Bcl₂ which was accompanied by collapse of mitochondrial membrane potential (MMP), cytosolic release of cytochrome c and Smac, and apoptotic cell death. Additionally, tetrandrine-induced JNK1/2 activation increased the phosphorylation of Bcl₂ at Ser70 and facilitated its degradation via the ubiquitin-mediated proteasomal pathway. In parallel, tetrandrine-mediated ROS generation also caused the induction of ligand-independent Fas-mediated apoptosis by activating procaspase-8 and Bid cleavage. Inhibition of procaspase-8 activation attenuated the cleavage of Bid, loss of MMP and caspase-3 activation suggest that tetrandrine-induced Fas-mediated apoptosis is associated with the mitochondrial pathway. Furthermore, most of the signaling effects of tetrandrine on apoptosis were significantly attenuated in the presence of antioxidant N-acetyl-l-cysteine, thereby confirming the involvement of ROS in these events. In conclusion, the results of the present study indicate that tetrandrine-induced apoptosis in prostate cancer cells is initiated by ROS generation and that both intrinsic and extrinsic pathway contributes to cell death.     

Induction of mitochondria-dependent apoptosis by Abrus agglutinin derived peptides in human cervical cancer cell.

In our previous study, Abrus agglutinin showed antitumor activity both native and heat-denatured condition in mouse model. The purpose of this study is to explore the presence of anticancer peptide in agglutinin, and to elucidate the mechanism of its activity in vitro. A tryptic digested Abrus agglutinin peptide fractions obtained from 10-kDa molecular weight cut off membrane permeate (10 kMPP), was found to have selective antiproliferative activity (1-10 microg/ml) on several tumor cell lines in vitro without having any cytotoxic effect on normal cell lines with dose of 100 microg/ml. Analysis of the growth inhibitory mechanism in HeLa cells revealed nuclear fragmentation and condensation with appearance of the sub-G 0/G1 peak indicative of apoptosis. Furthermore, the peptide fraction induced the apoptosis signal via generation of reactive oxygen species and decrease in the Bcl-2/Bax ratio thereby inducing mitochondrial permeability transition with consequent activation of caspase-3, finally leads to DNA fragmentation, and the hallmark of apoptosis. LC-MS/MS analysis reflected the molecular masses of peptides in 10 kMPP were in the range of 500 Da to 3000 Da. The significant antitumor activity of 10 kMPP deserves further laboratory and in vivo experimentation.     

Combinatorial nanoparticles for cancer diagnosis and therapy

Nanotechnology when engineered together with biotechnology opens a fascinating field with applications in diverse areas such as drug targeting and delivery, medical imaging, biosensing, biomaterials and nanotechnology. Conjugating nanoparticles with biomolecules like QD-herceptin conjugates or QD-aptamer (Apt)-DOX conjugates provides many opportunities for improving many of the current challenges in cancer diagnosis and therapy. This paper reviews combinatorial nanoparticles designed and formulated for cancer imaging and therapy, including inorganic nanoparticles (quantum dots, iron oxide particles, gold nanoparticles and silica and carbon nanoparticles), polymeric nanoparticles (PLGA, PLGA-PEG, PAMAM), liposomes and lipid nanoparticles. These nanoparticles are multifunctional in nature and combine two or more functions like targeting, imaging and therapy. In this review, we have classified these combinatorial targeted nanoparticles into inorganic, polymeric and liposome based nanosystems.     

Effects of smokeless tobacco on chemically transformed hamster oral keratinocytes: role of angiotensin I-converting enzyme

The purpose of this study was to determine whether exposureof chemically transformed golden Syrian hamster oral epidermoidcarcinoma cell (HCPC-1) cultures to smokeless tobacco extract(STE) is associated with a decrease in specific angiotensinI-converting enzyme (ACE) activity and whether this decreasepotentiates bradykinin-induced cell growth. We found that STEinduced a significant concentration- and time-dependent decreasein ACE activity in cultured HCPC-1 cells (P <0.05). STE alonehad no significant effect on cell number. Bradykinin alone induceda slight, but significant, increase in cell number (P <0.05).These effects were signific potentiated by STE (P <0.01).We conclude that STE potentiates bradykinin-induced HCPC-1 cellgrowth, in part by attenuating specific ACE activity in thesecells.     

Serial estimation of Th1:th2 cytokines profile in women undergoing in-vitro fertilization-embryo transfer

PROBLEM: To investigate changes in the ratio of T-cell subpopulations expressing intracellular T helper1 (Th1) and T helper 2 (Th2) cytokines in women with a history of recurrent failed implantation under going in-vitro fertilization (IVF)-embryo transfer. METHOD OF STUDY: Twenty-eight peripheral blood samples were obtained at two time points, from 14 women undergoing IVF treatment; eight women with a history of recurrent failed implantation, who did not get pregnant in the index IVF cycle and six who had one or more previous successful IVF pregnancy and who became pregnant in the index IVF cycle. The proportion of lymphocytes expressing interferon-gamma (IFN-gamma), tumour necrosis factor-alpha (TNF-alpha), and interleukin 4 (IL-4) and the Th1:Th2 ratios of IFN-gamma:IL-4, and TNF-alpha:IL-4 in T helper cells was measured by flow cytometry, in samples obtained before commencing IVF treatment and in samples obtained after ovarian stimulation (on the day of oocyte retrieval). RESULTS: In samples collected during oocyte retrieval, women with a history of recurrent failed implantation had a higher IFN-gamma:IL-4 and TNF-alpha:IL-4 ratio than the control group, (18.6+/-9.3 versus 6.47+/-1.68, P=0.009) and (39.1+/-15.7 versus 11.53+/-3.76, P=0.001) respectively. In women with a history of recurrent failed implantation the ratio of IFN-gamma:IL-4 and TNF-alpha:IL-4 at oocyte retrieval was higher than pre-treatment ratios (18.6+/-9.3 versus 12.01+/-9.8, P=0.018) and 39.10+/-15.7 versus 18.66+/-11.42, P=0.010) respectively, showing a Th1 bias. In women with a successful IVF the converse was true; the ratio at oocyte retrieval was significantly lower than pre-treatment ratios (6.47+/-1.68 versus 9.37+/-6.8, P=0.035) and 11.53+/-3.76 versus 18.60+/-12.9, P=0.027) respectively, representing a Th2 bias. CONCLUSION: Women with a history of unexplained recurrent failed IVF treatment have a Th1 bias and this polarization is more enhanced following hormonal manipulations during IVF treatment. Comparing pre-treatment ratios of IFN-gamma:IL-4 and TNF-alpha:IL-4 to ratios obtained at oocyte retrieval may be clinically useful. Women with recurrent failed IVF have increasing ratios.     

The post-baccalaureate premedical certification program at the University of North Texas Health Science Center strengthens admission qualifications for entrance into medical school.

The Post-Baccalaureate (postbac) Premedical Certification Program at the University of North Texas Health Science Center provides an opportunity for individuals to enhance their credentials for entry into medical school by offering a challenging biomedical science core curriculum in graduate biochemistry, cell biology, physiology, and pharmacology. In addition, students (called postbacs) receive instruction in human gross anatomy, histology, and embryology with first-year medical students. More than 90% of the students accepted into the postbac program have applied to medical school previously but have been rejected by admission committees at least once, primarily because of low cognitive scores. In spring 2001, seven postbacs completed the program, of which only one was admitted into the Texas College of Osteopathic Medicine (TCOM), the medical school affiliated with the University of North Texas Health Science Center. Three postbacs went to other medical schools. Thirty-one completed the program by spring 2006, of whom 13 were admitted to TCOM, and eight to other medical schools. After six years, 101 postbacs have completed the program, and 70 have been accepted into medical schools. Postbacs admitted into TCOM have performed well compared with their medical school classmates. Overall, average scores for postbacs are above those of their medical school classmates. In addition, postbacs have taken class leadership positions, served as tutors and mentors, and have served as school ambassadors for new applicants. The postbac premedical program has proven to be very successful in preparing students for the rigors of a medical school curriculum by allowing these students to develop the skills and confidence necessary to compete.