Bacterial Proteins and Peptides as Potential Anticancer Agents: A Novel Search for Protein-based Therapeutics

Tumor diseases remain among the world's primary causes of death despite substantial advances in cancer diagnosis and treatment. The adverse chemotherapy problems and sensitivity towards drugs for some cancer types are among the most promising challenges in modern treatment. Finding new anti-cancer agents and drugs is, therefore, essential. A significant class of biologically active substances and prospective medications against cancer is comprised of bacterial proteins and peptides. Among these bacterial peptides, some of them, such as anti-cancer antibiotics and many toxins like diphtheria are widely being used in the treatment of cancer. In contrast, the remaining bacterial peptides are either in clinical trials or under research in vitro studies. This study includes the most recent information on the characteristics and mechanism of action of the bacterial peptides that have anti-cancer activities, some of which are now being employed in cancer therapy while some are still undergoing research.

A circulating microvesicle-based biosignature for the detection of colorectal cancer

373

Background: Microvesicles are principally derived either from the endosomal pathway (as exosomes) or shed directly from the plasma membrane. They are between 40-500 nm in diameter and are secreted by most cell types, including tumor cells. In circulation, microvesicles appear to participate in cellular communication by transporting mRNAs, miRs and proteins from their cell of origin to target cells where they can elicit biological responses. The quantity and protein topography of microvesicles shed from cancer cells varies considerably compared to those shed from normal cells. Thus, the concentration of circulating plasma microvesicles with molecular markers indicative of the disease state can be used as a robust and informative blood-based biosignature. In this study we report the results of the application of a novel multiplexed method for quantifying and profiling microvesicles in plasma for the detection of colorectal cancer.

Methods: We have developed a versatile mulitplexed microvesicle-based discovery panel with 73 different antibodies that target surface proteins of various microvesicle subpopulations. This system was used to develop a microvesicle-derived biosignature composed of 2 different surface membrane protein biomarkers.

Results: In this study, we demonstrate that a combination of TMEM211 and CD24 provide a robust signature for the detection of colorectal cancer (CRC). We isolated microvesicles from plasma of 257 patients with CRC, 57 stage I, 104 stage II, 80 stage 3, 6 stage IV, and 11 of unknown stage; 327 self-described, age-range matched normal plasma specimens were used for the control population. The level of TMEM211 and CD24 containing microvesicles for these samples was determined using a multiplexed immunoassay. Thresholds were empirically determined to maximize the sensitivity and specificity of CRC detection, resulting in a sensitivity of 90% with a specificity of 85% with an AUC of .91.

Conclusions: This study demonstrates that it is possible to use circulating microvesicles for the development of a highly sensitive and specific blood-based assay to detect CRC.

[Table: see text]

The incidence of prostate cancer in patients under the age of 60 from an urban setting

14622

Background: Although the risk for developing prostate cancer increases with age, few studies have reported the incidence of prostate cancer in men younger than 60 from an urban setting. Methods: All patients diagnosed and treated for prostate cancer at The Cancer Institute of New Jersey at Cooper University Hospital in Camden County, New Jersey from January 1, 2004 to December 31, 2004 were retrospectively identified from our tumor registry. Age comparison at diagnosis was made utilizing the Cooper registry and the National Cancer Database (NCDB), 2001. Results: A total of 141 men (88 Caucasians, 37 African Americans, 14 Hispanic, and 6 unknown) with a median age of 64 years (range, 44–88 years) were diagnosed with prostate cancer in 2004. Staging revealed Stage II (118), Stage III (3), Stage IV (4), Stage unknown (16) cases. Median Gleason score was 6. 74 patients underwent radical prostatectomy, 50 had radiation, 30 received hormone therapy and 2 received chemotherapy. At diagnosis, 19.95% of the men were under 50 and 41.84% were under 60 years of age. Our dataset from these two age groups compared to NJ and US figures are noted below. Conclusions: When comparing the respective data sets from CINJ at Cooper to NJ and US utilizing the NCDB, there are striking differences with a higher incidence of prostate cancer in younger men. These incidences parallel those seen in other urban university teaching hospitals from the Healthcare Utilization Project (2005), where more patients under the age of 60 are being diagnosed with prostate cancer when compared to community centers. Subset analysis shows that our institution had a disproportionately larger number of African American men with prostate cancer which may relate to our culturally directed screening program, accounting for the higher incidence. These data support that hospital characteristics may impact age at diagnosis of prostate cancer, and further investigation is warranted. [Table: see text]

No significant financial relationships to disclose.

Improved survival in patients with locally advanced esophageal cancer utilizing a multidisciplinary approach

14130

Background: Locally advanced esophageal cancer studies have reported a three year overall survival rate of 32% with a median survival of 16 months. These patients were treated with combined chemotherapy and radiation with surgery, when applicable. We conducted this study to determine whether using an individualized, multidisciplinary approach affected survival outcomes in patients treated for locally advanced esophageal cancer. Methods: All patients treated for locally advanced esophageal cancer were retrospectively identified from our database at The Cancer Institute of New Jersey at Cooper University Hospital. All patients were presented and discussed in a multidisciplinary gastrointestinal tumor board conference. After a consensus was obtained, a treatment plan was established for each patient based on his or her respective clinical characteristics: stage, performance status, medical suitability for surgery and resectabilty. Results: A total of 23 patients (median age: 66 years [range, 55–88 years]) were identified, the histopathologic diagnosis was adenocarcinoma in 13 and squamous cell carcinoma in 10 cases. TNM staging was as follows: 18 (78.3%) stage II or III and 5 (21.7%) stage IV. Initial management included esophagectomy for 9 (39.1%), 6 of which received preoperative chemotherapy (5-FU) and three received postoperative adjuvant chemotherapy, 14 (60.9%) received only combined chemotherapy (average four cycles of 5FU 1000 mg per square meter of body surface + Cisplatin 75 mg per square meter of body surface) and radiation at doses 50–64 Gy. Overall median survival was not reached since only five patients (21.7%) have died. The 1- year and 2-year survival rates were 87% and 74% respectively. Median follow-up for patients who received combination chemotherapy and radiation vs. surgery with preoperative therapy was 29 and 41 months, respectively. Conclusion: This retrospective analysis shows promising outcomes compared to published data supporting the role of an individualized, multidisciplinary approach in the management of each patient with esophageal cancer.

No significant financial relationships to disclose.