Mechanisms of metastasis: seed and soil

Unravelling the epigenetic based mechanism in discovery of anticancer phytomedicine: Evidence based studies

Epigenetic mechanisms play a crucial role in the normal development and maintenance of tissue-specific gene expression patterns in mammals. Disruption of these processes can result in changes to gene function and the transformation of cells into a malignant state. Cancer is characterized by widespread alterations in the epigenetic landscape, revealing that it involves not only genetic mutations but also epigenetic abnormalities. Recent progress in the field of cancer epigenetics has demonstrated significant reprogramming of various components of the epigenetic machinery in cancer, such as DNA methylation, modifications to histones, positioning of nucleosomes, and the expression of non-coding RNAs, particularly microRNAs. The ability to reverse epigenetic abnormalities has given rise to the hopeful field of epigenetic therapy, which has shown advancement with the recent approval by the FDA of three drugs targeting epigenetic mechanisms for the treatment of cancer. In the present manuscript, a comprehensive review has been presented about the role of understanding the epigenetic link between cancer and mechanisms by which phytomedicine offers treatment avenues. Further, this review deciphers the significance of natural products in the identification of epigenetic therapeutics, the diversity of their molecular targets, the use of nanotechnology, and the creation of new strategies for overcoming the inherent clinical challenges associated with developing these drug leads.

Can Biologic Aggressiveness and Metastatic Potential of Primary Lung Cancer Be Predicted from Clinical Staging Alone?

The future biologic aggressiveness and metastatic potential of lung cancer, as in other cancers, cannot be predetermined from the current clinical information, imaging studies, and pathologic examination whose purpose is to provide diagnosis and mutation studies and molecular drivers only in making decision for treatment. There is a need for better understanding of the biologic characteristics and aggressiveness of lung cancer. The most that is achieved from clinical staging and pathologic staging is in the planning of treatment of lung cancer and predicting prognosis. Aggressive biologic behavior to come is not within the domain of clinical staging or pathologic staging.

Correlation between Cell Proliferation with Cervical Lymphoid Node Status in Nasopharyngeal Carcinoma Patients

Several studies showed that the index of nasopharyngeal carcinoma (NPC) cell growth could be used to assess the carcinogenesis interaction factor, development and prognosis of NPC. Cell proliferation index could always be assessed with Ki-67 protein expression test. This research was conducted to study the correlation between cell proliferation index with cervical lymphoid node status in NPC in clinical manifestation to asses the progressivity and prognosis on NPC patients. This study used cross sectional design. Biopsy tissue specimen were acquired from 35 NPC patients clinically divided into four criteria of cervical lymphoid node status (N0, N1, N2 and N3). Expression of Ki-67 protein was acquired by immunohistochemistry test using monoclonal rabbit antibody anti-human Ki-67 clone 901-325-091911 (Biocare Medical, LCC. 4040 Pike Line, CA 94520 USA). The measurement of Ki-67 protein was conducted by pathology consultant. Spearman statistic test was performed to asses the correlation between Ki-67 protein expression and cervical lymphoid node status. The statistical significance was defined as p<0.05. Positive expression of Ki-67 protein was found in 33 patients; 4 patients with N0 (11.43%), 5 patients with N1 (14.29%), 9 patients with N2 (25.71%), and 15 patients with N3. Negative expression of Ki-67 protein was found in 2 patients with N0 (5.71%). The Spearman test resulted at p=0.0001 with correlation coefficient of 0.758. The correlation between Ki-67 protein expression with cervical lymphoid node resulted in a significant correlation (p<0.05). In conclusion, cell proliferation index has correlation with cervical lymphoid node status in NPC patients.

Epigenetics and cancer

Epigenetic modifications are central to many human diseases, including cancer. Traditionally, cancer has been viewed as a genetic disease, and it is now becoming apparent that the onset of cancer is preceded by epigenetic abnormalities. Investigators in the rapidly expanding field of epigenetics have documented extensive genomic reprogramming in cancer cells, including methylation of DNA, chemical modification of the histone proteins, and RNA-dependent regulation. Recognizing that carcinogenesis involves both genetic and epigenetic alterations has led to a better understanding of the molecular pathways that govern the development of cancer and to improvements in diagnosing and predicting the outcome of various types of cancer. Studies of the mechanism(s) of epigenetic regulation and its reversibility have resulted in the identification of novel targets that may be useful in developing new strategies for the prevention and treatment of cancer.

A distinct macrophage population mediates metastatic breast cancer cell extravasation, establishment and growth

Background

The stromal microenvironment and particularly the macrophage component of primary tumors influence their malignant potential. However, at the metastatic site the role of these cells and their mechanism of actions for establishment and growth of metastases remain largely unknown.

Methodology/Principal Findings

Using animal models of breast cancer metastasis, we show that a population of host macrophages displaying a distinct phenotype is recruited to extravasating pulmonary metastatic cells regardless of species of origin. Ablation of this macrophage population through three independent means (genetic and chemical) showed that these macrophages are required for efficient metastatic seeding and growth. Importantly, even after metastatic growth is established, ablation of this macrophage population inhibited subsequent growth. Furthermore, imaging of intact lungs revealed that macrophages are required for efficient tumor cell extravasation.

Conclusion/Significance

These data indicate a direct enhancement of metastatic growth by macrophages through their effects on tumor cell extravasation, survival and subsequent growth and identifies these cells as a new therapeutic target for treatment of metastatic disease.