|Year : 2010 | Volume
| Issue : 3 | Page : 464-465
Human alpha-lactalbumin made lethal to tumors: Can it be a new intravesical therapy for bladder cancer?
Amod Kumar Dwivedi, Apul Goel, SN Shankhwar
Department of Urology, CSMMU (upgraded KGMC), Lucknow, Uttar Pradesh, India
|Date of Web Publication||1-Oct-2010|
Department of Urology, CSMMU (upgraded KGMC), Lucknow, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Dwivedi AK, Goel A, Shankhwar S N. Human alpha-lactalbumin made lethal to tumors: Can it be a new intravesical therapy for bladder cancer?. Indian J Urol 2010;26:464-5
|How to cite this URL:|
Dwivedi AK, Goel A, Shankhwar S N. Human alpha-lactalbumin made lethal to tumors: Can it be a new intravesical therapy for bladder cancer?. Indian J Urol [serial online] 2010 [cited 2019 Aug 19];26:464-5. Available from: http://www.indianjurol.com/text.asp?2010/26/3/464/70601
Mossberg A, Hou Y, Svensson M, Holmqvist B, Svanborg C. HAMLET Treatment Delays Bladder Cancer Development. J Urol 2010;183:1590-7.
| Summary|| |
HAMLET (Human Alpha-lactalbumin Made Lethal to Tumors) is a molecular complex derived from human milk that kills tumor cells by a process resembling programmed cell death (apoptosis). In a trial of 9 patients of superficial bladder cancer, pre-transurethral resection of bladder tumor (TURBT) intravesical instillation of HAMLET has been found to stimulate apoptotic response in tumors and caused significant reduction in tumor size.  In order to further assess its efficacy and molecular mechanism, an animal bladder cancer model was required and MB49 mouse bladder cancer cell model was found to be a useful candidate. The bladder carcinoma cell lines, originally isolated from a carcinogen-induced bladder tumor in mice, grow rapidly and establish a local mass within a week that mimic the growth of human infiltrating urothelial carcinoma. The present study aims at evaluating the therapeutic effects of HAMLET for bladder carcinoma in a murine bladder cancer model.  The study also included in vitro cell death assay for direct microscopic visualization of apoptotic activity, cell viability, and morphologic changes in response to HAMLET. The cells were cultured in cell culture media and exposed to either HAMLET or native alpha-lactalbumin as control. The cell viability was tested using trypan blue exclusion staining and the apoptotic cells were identified using the TUNEL (terminal deoxynucleotidyl transferase biotin-dUTP nick-end labeling) assay. HAMLET was found to cause rapid dose-dependent cell death in response to 3-h instillation, whereas the same concentrations of native alpha-lactalbumin did not induce cell death.
Cultured cancer cells had shown morphologic changes in phase contrast microscopy and evidence of apoptosis on TUNEL staining after treatment with HAMLET, whereas cultured differentiated cells have not shown the above effects on exposure to HAMLET.
In a parallel study, female mice underwent intravesical instillation of MB49 tumor cells followed by 5 instillations of HAMLET or phosphate buffer solution (PBS) at indicated intervals. The mice were sacrificed at a defined time point, and bladders harvested. Tumor area determination after tissue sections revealed a significant reduction in the tumor size in those mice receiving HAMLET in comparison with those receiving PBS. Strongly positive TUNEL staining of tumor tissue exposed to HAMLET when compared with the negative staining of the adjacent normal bladder tissue confirmed specificity of HAMLET to neoplastic tissue alone.
Wholebody fluorescent imaging done 2 days after the intravesical instillation of Alexa-HAMLET (fluorescent-labeled HAMLET) localized it only to the tumor, sparing the adjacent normal urothelium.
Results in this study have shown that HAMLET was retained in tumor tissue, kills tumor cells and delays tumor growth.
| Comments|| |
Although for a long time human breast milk has been known to have anti-infective properties in the form of lysozymes and antibodies, the finding of antineoplastic activity of breast milk is recent. This came to light incidentally when human lung cancer cell lines were found to be killed by human milk, while investigating the effect of human milk on bacterial adherence to these cells.  Later investigations identified alpha-lactalbumin, one of the main proteins in human milk, in particular physical state, to cause cellular death of multiple cancer cell lines, mainly by inducing rapid apoptosis. The uniqueness of this multimeric, transformed alpha-lactalbumin (HALMET) as an antineoplastic agent is that it spares mature epithelial cells. HAMLET is a protein-lipid complex of alpha-lactalbumin and oleic acid formed in the stomach after breast feeding. Acid PH of the stomach causes release of tightly bound Ca ++ from alpha-lactalbumin causing changes in the tertiary structure of the protein. At the same time, stomach lipases get activated by calcium and start digesting the triglycerides. Oleic acid released in this process binds with transformed alpha-lactalbumin and forms a multimeric complex. This multimeric complex named HAMLET, is nature's device to induce apoptosis of undifferentiated and neoplastic cells and so, protecting the child from malignancies. It was speculated that HAMLET must have an impact on some very basic processes of cell survival leading to such widespread apoptotic activity in diverse cancer cell lines. HAMLET is selectively internalized by neoplastic and undifferentiated cells and effect cellular killing by multiple pathways, most important of which is the translocation to nuclei and impairing the transcriptional machinery by high-affinity binding to histones and nucleosomes. Other mechanisms are rapid mitochondrial destruction and activation of 20S proteosomes. 
HAMLET has been tested in a rat xenograft model of human glioblastoma. Tumor cell death was observed after injection of HAMLET into the brain, but there was no apoptotic response in healthy brain tissue surrounding the tumor and no evidence of toxicity after injection of HAMLET into healthy rat brains.  HAMLET was also shown to efficiently remove or reduce human skin papillomas in a placebo-controlled clinical study. 
In a small study of 9 male patients awaiting transurethral surgery for superficial bladder cancer, pre-TURBT intravesical instillations of HAMLET were done for 5 days. HAMLET had not only tremendously increased shedding of apoptotic cancer cells in urine but also caused a significant reduction in the tumor size. 
The present study has almost confirmed antineoplastic activity of HAMLET and has far-reaching implications in the management of superficial bladder cancer. Larger clinical trials and more experimental molecular studies are needed before it can be used as a regular intravesical treatment for bladder cancer.
| References|| |
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|2.||Mossberg A, Hou Y, Svensson M, Holmqvist B, Svanborg C. HAMLET Treatment Delays Bladder Cancer Development. J Urol 2010;183:1590-7. |
|3.||Hakansson A, Zhivotovsky B, Orrenius S, Sabarwal H, Svanborg C. Apoptosis induced by a human milk protein. Proc Natl Acad Sci 1995;92:8064-8. |
|4.||Svanborg C, Agerstam H, Aronson A, Bjerkvig R, Dόringer C, Fischer W, Gustafsson L, et al. HAMLET kills tumor cells by an apoptosis-like mechanism- cellular, molecular, and therapeutic aspect. Adv Cancer Res 2003;88:1. |
|5.||Fischer W, Gustafsson L, Mossberg AK, Gronli J, Mork S, Bjerkvig R, et al. Human alpha-lactalbumin made lethal to tumor cells (HAMLET) kills human glioblastoma cells in brain xenografts by an apoptosis-like mechanism and prolongs survival. Cancer Res 2004;64:2105. [PUBMED] [FULLTEXT] |
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