An integrated approach to finding new treatments for breast cancer

December 12, 2018

Unraveling the complexity of cancer biology can lead to the identification new molecules involved in breast cancer and prompt new avenues for drug development. And proteogenomics, an integrated, multipronged approach, seems to be a way to do it.

"Our approach to finding new treatments for cancer is to conduct integrated analyses of multiple components of tumor biology through the study of tumor DNA, RNA, proteins and phosphoproteins (proteins tagged with a phosphate chemical group) in order to find targets that are present in only one breast cancer subtype. We then investigate whether these 'proteogenomic' subtype outliers could be contributing to the disease in unique ways," said Dr. Matthew Ellis, professor and director of the Lester and Sue Smith Breast Center, McNair scholar and associate director of precision medicine at the Dan L Duncan Comprehensive Cancer Center at Baylor College of Medicine.

Such analyses pointed to DPYSL3 as a molecule whose expression was altered at multiple levels -- RNA, protein and phosphoprotein -- in a particular type of breast cancer called Claudin-Low triple-negative breast cancer. Having alterations at multiple levels makes DPYSL3 a good candidate for further laboratory studies searching for new therapies for this aggressive and highly metastatic breast cancer subtype.

"When we knocked down gene DPYSL3 in breast cancer cells in the lab, we observed a complex response," Ellis explained. "The cells stopped dividing properly and accumulated nuclei due a failure to undergo cell division. However, cells without DPYSL3 also became more mobile. These results told us that DPYSL3 affects cell proliferation and the ability to move and metastasize, but in opposite ways."

The vimentin connection

The researchers then focused on exploring how DPYSL3 mediated its effects on cell division. They focused on vimentin because a recent report indicated that another compound interacting with vimentin had similar effects on cell division as the one observed in the DPYL3 knockdown. Vimentin expression also is a feature of highly aggressive breast cancers.

"It appears that Claudin-Low triple-negative breast cancer cells require low levels of vimentin tagged with a phosphate group to successfully complete cell division," Ellis said. "When we knocked down DPYSL3, vimentin levels rose and cell division malfunctioned," Ellis said. "These finding suggests that cancer cells expressing DPYLS3 could be treated with a drug that inhibits the removal of phosphate groups from vimentin."

Regarding the effects of DPYSL3 on cell motility, Ellis explains that DPYSL3 is known to regulate PAK kinases, a group of enzymes that are important for the cell's ability to move and undergo the metastatic transition. "When DPYSL3 is suppressed, PAK becomes more active and the cells more metastatic."

These findings have opened a new avenue that might treat the most aggressive forms of breast cancer by combined targeting of the mechanisms that connect DPYSL3 with vimentin and PAK kinases.

"This work shows the tremendous value of proteogenomics in the identification of new molecules involved in breast cancer that could lead to novel treatments," Ellis said. "Baylor College of Medicine is a world leader in proteogenomic approaches to translational medicine, which is at the core of the precision medicine approach we are developing."

Interested in reading all the details of this work> Find them in the Proceedings of the National Academy of Sciences.
-end-
Other contributors to this work include Ryoichi Matsunuma, Doug W. Chan, Beom-Jun Kim, Purba Singh, Airi Han, Alexander B. Saltzman, Chonghui Cheng, Jonathan T. Lei, Junkai Wang, Leonardo Roberto da Silva, Ergun Sahin, Mei Leng, Cheng Fan, Charles M. Perou and Anna Malovannaya. The authors are affiliated with one or more of the following institutions: Baylor College of Medicine; Hamamatsu University School of Medicine, Japan; University Wonju College of Medicine, Korea; State University of Campinas-UNICAMP, Brazil; University of North Carolina, Chapel Hill; and Hamamatsu Oncology Center, Japan.

This work was primarily supported by Cancer Prevention Institute of Texas Recruitment of Established Investigators Award RR14033, the McNair Foundation and the Eads Fund for Metastatic Breast Cancer Research. Additional support was provided by Susan G. Komen for the Cure Grants BCTR0707808, KG090422, and PG12220321; Clinical and Translational Science Award Grant UL1 RR024992; the Breast Cancer Research Foundation, the National Cancer Institute Breast SPORE Program Grants P50-CA58223, R01-CA148761 and Clinical Proteomic Tumor Analysis Consortium funding, including U01CA214125 and U24 CA160035.

Baylor College of Medicine

Related Breast Cancer Articles from Brightsurf:

Oncotarget: IGF2 expression in breast cancer tumors and in breast cancer cells
The Oncotarget authors propose that methylation of DVDMR represents a novel epigenetic biomarker that determines the levels of IGF2 protein expression in breast cancer.

Breast cancer: AI predicts which pre-malignant breast lesions will progress to advanced cancer
New research at Case Western Reserve University in Cleveland, Ohio, could help better determine which patients diagnosed with the pre-malignant breast cancer commonly as stage 0 are likely to progress to invasive breast cancer and therefore might benefit from additional therapy over and above surgery alone.

Partial breast irradiation effective treatment option for low-risk breast cancer
Partial breast irradiation produces similar long-term survival rates and risk for recurrence compared with whole breast irradiation for many women with low-risk, early stage breast cancer, according to new clinical data from a national clinical trial involving researchers from The Ohio State University Comprehensive Cancer Center - Arthur G.

Breast screening linked to 60 per cent lower risk of breast cancer death in first 10 years
Women who take part in breast screening have a significantly greater benefit from treatments than those who are not screened, according to a study of more than 50,000 women.

More clues revealed in link between normal breast changes and invasive breast cancer
A research team, led by investigators from Georgetown Lombardi Comprehensive Cancer Center, details how a natural and dramatic process -- changes in mammary glands to accommodate breastfeeding -- uses a molecular process believed to contribute to survival of pre-malignant breast cells.

Breast tissue tumor suppressor PTEN: A potential Achilles heel for breast cancer cells
A highly collaborative team of researchers at the Medical University of South Carolina and Ohio State University report in Nature Communications that they have identified a novel pathway for connective tissue PTEN in breast cancer cell response to radiotherapy.

Computers equal radiologists in assessing breast density and associated breast cancer risk
Automated breast-density evaluation was just as accurate in predicting women's risk of breast cancer, found and not found by mammography, as subjective evaluation done by radiologists, in a study led by researchers at UC San Francisco and Mayo Clinic.

Blood test can effectively rule out breast cancer, regardless of breast density
A new study published in PLOS ONE demonstrates that Videssa® Breast, a multi-protein biomarker blood test for breast cancer, is unaffected by breast density and can reliably rule out breast cancer in women with both dense and non-dense breast tissue.

Study shows influence of surgeons on likelihood of removal of healthy breast after breast cancer dia
Attending surgeons can have a strong influence on whether a patient undergoes contralateral prophylactic mastectomy after a diagnosis of breast cancer, according to a study published by JAMA Surgery.

Young breast cancer patients undergoing breast conserving surgery see improved prognosis
A new analysis indicates that breast cancer prognoses have improved over time in young women treated with breast conserving surgery.

Read More: Breast Cancer News and Breast Cancer Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.