Inhibition of angiogenesis as a strategy for tumor growth control

Etiologic Role of Kinases in the Progression of Human Cancers and Its Targeting Strategies

Cancer is one of the dominant causes of death worldwide while lifelong prognosis is still inauspicious. The maturation of the cancer is seen as a process of transformation of a healthy cell into a tumor-sensitive cell, which is held entirely at the cellular, molecular, and genetic levels of the organism. Tyrosine kinases can play a major, etiologic role in the inception of malignancy and devote to the uncontrolled proliferation of cancerous cells and the progression of a tumor as well as the development of metastatic disease. Angiogenesis and oncogene activation are the major event in cell proliferation. The growth of a tumor and metastasis are fully depending on angiogenesis and lymphangiogenesis triggered by chemical signals from tumor cells in a phase of rapid growth. Tyrosine kinase inhibitors are compounds that inhibit tyrosine kinases and effective in targeting angiogenesis and blocking the signaling pathways of oncogenes. Small molecule tyrosine kinase inhibitors like afatinib, erlotinib, crizotinib, gefitinib, and cetuximab are shown to a selective cut off tactic toward the constitutive activation of an oncogene in tumor cells, and thus contemplated as promising therapeutic approaches for the diagnosis of cancer and malignancies.

Characterization of a transplantable hormone-responsive human prostatic cancer xenograft TEN12 and its androgen-resistant sublines

BACKGROUND

Models for human prostate cancer can facilitate the study of resistance to endocrine therapy, aid drug discovery, and pre-clinical assessment.

METHODS

Characteristics thought relevant to the growth in athymic nude mice of TEN12, an androgen-dependent transplantable prostatic cell line derived from a primary prostate carcinoma, and its two androgen-independent sublines, TEN12F and TEN12C, have been assessed immunocytochemically.

RESULTS

The xenografts of the parental TEN12 line are moderately differentiated with both papillary and glandular regions, pleomorphic nuclei and abundant mitotic figures and are extremely vascular. The cells express androgen receptor (AR), PSA, VEGF, EGFR, c-erbB2, and TGFalpha. Both TEN12F and TEN12C xenografts possessed a more anaplastic morphology and displayed significantly lower growth rates, reduced blood vessel density (BVD), decreased MIB-1 antigen and E-cadherin expression and increased cytoplasmic AR and HSP90 staining. Elevated EGFR (membrane) but not c-erbB2 expression was demonstrated in the TEN12F line only. Castration of mice bearing TEN12 xenografts rapidly induced the appearance of cytoplasmic AR in the cells, PSA levels decreased initially but recovered to below pre-castration levels whilst reduced TGFalpha and loss of VEGF expression was seen in the long-term castrates.

CONCLUSIONS

TEN12 and its sublines offer additional in vivo models to study the factors involved in the progression of prostatic cancer to androgen-independence.