8.5 Cancers of the Colon and Rectum


Roughly 95 percent of all colorectal cancers are adenocarcinomas — they start as polyps in the mucus glands of the colon or rectum and then become cancerous[colon]. Unless otherwise noted, the studies mentioned in this article were carried out on adenocarcinomas. They are primarily in vitro studies.

Colorectal cancer is the third leading cause of cancer deaths.

Killing Cancer Cells

CBD kills colon cancer cells[kill-cbd]. So does CBG[kill-cbg]. The following cannabis terpenes kill colorectal cancer cells: α-humulene[kill-hum], eucalyptol (aka 1, 8-cineole)[kill-euca], borneol[kill-born], and geraniol[kill-ger].

BCP (β-Caryophyllene) enhances the effectiveness of conventional cancer drugs when tested on chemo drugs such as paclitaxel[kill-bcp1] and doxorubicin[kill-bcp2]. β-Caryophyllene oxide, trans-nerolidol, and valencene also enhance the effectiveness of doxorubicin[kill-bcpo][kill-bcp2]. Geraniol enhances the effectiveness of the otherwise ineffective chemo dug 5-fluorouracil[kill-ger2].

Stopping Cell Replication

A high-CBD cannabis extract reduced proliferation both in vitro and in an animal study[repl-cbd].

The following cannabis terpenes inhibit cell replication: BCP (β-caryophyllene)[repl-bcp], BCPO (β-caryophyllene oxide)[repl-h], geraniol[repl-ger], α-humalene[repl-h], trans-nerolidol[repl-h], valencene[repl-h]. Apigenin also inhibits replication[repl-api].

Inhibiting Invasion and Metastasis

BCP (β-Caryophyllene) inhibits tumor motility, migration, and invasion in colorectal cancer[repl-bcp].

Controlling Cytokines

THCA inhibits growth in colon cancer by lowering IL-8[Nallathambi_2017].

The inflammatory cytokines IL-1β[ping_2016], IL-6[Cui_2018], IL-8[WikiMedicine_2021], IL-17[Cui_2018a], IL-21[Stolfi_2011], IL-22[Markota_2018]. TNF-α[Simone_2014], and VEGF[Eldesoky_2011] are all elevated in colorectal cancer. They all appear to promote cancer growth.

IL-8 stimulates the growth of human colon cancer cells[Li_2001]. IL-1α promotes migration and angiogenesis[Ma_2015]. IL-8 and IL-17 promote invasiveness[Li_2001][Cui_2018a]. IL-17 promotes metastasis[Hyun_2012]. Most of these results are known to apply to colitis-associated cancers in particular[Stolfi_2011][Grivennikov_2009].

Some general ideas on controlling cytokines are given in Taming Inflammatory Cytokines


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kill-bcp1. Potentiating effect of beta-caryophyllene on anticancer activity of alpha-humulene, isocaryophyllene and paclitaxel [in vitro study]. Abstract. Jean Legault, André Pichette. Journal of pharmacy and pharmacology. Published 2007 December.

kill-bcp2. The Influence of Sesquiterpenes from Myrica rubra on the Antiproliferative and Pro-Oxidative Effects of Doxorubicin and Its Accumulation in Cancer Cells. Article. Martin Ambrož, Iva Boušová, Adam Skarka, et al. Molecules. Published 2015 August 21.

kill-bcpo. Chemosensitizing Properties of β-Caryophyllene and β-Caryophyllene Oxide in Combination with Doxorubicin in Human Cancer Cells. Article. Silvia DI Giacomo, Antonella DI Sotto, Gabriela Mazzanti, Michael Wink. Anticancer Research. Published 2017 March.

kill-hum. Antitumor activity of balsam fir oil: production of reactive oxygen species induced by alpha-humulene as possible mechanism of action [in vitro study]. Abstract. Jean Legault, Wivecke Dahl, Eric Debiton, et al. Planta medica. Published 2003 May.

kill-euca. Antitumor effect of 1, 8-cineole against colon cancer [in vitro study]. Article. Soichiro Murata, Risa Shiragami, Chihiro Kosugi. Oncology reports. Published 2013 October 1.

kill-born. Borneol [in Antitumor Activity of Monoterpenes Found in Essential Oils] [in vitro study]. Article section. Marianna Vieira Sobral, Aline Lira Xavier, Tamires Cardoso Lima, Damião Pergentino de Sousa. The scientific world journal. Published 2014 October 14.

kill-ger. Geraniol, a component of plant essential oils, modulates DNA synthesis and potentiates 5-fluorouracil efficacy on human colon tumor xenografts. Abstract. Stephanie Carnesecchi, Rui Bras-Gonçalves, Amyaouch Bradaia, et al. Cancer letters. Published 2004 November 8.

kill-ger2. Geraniol, a component of plant essential oils, sensitizes human colonic cancer cells to 5-Fluorouracil treatment. Abstract. S Carnesecchi, K Langley, F Exinger, et al. The Journal of pharmacology and experimental therapeutics. Published 2002 May.

repl-cbd. Inhibition of colon carcinogenesis by a standardized Cannabis sativa extract with high content of cannabidiol [in vitro study]. Abstract. BarbaraRomano, FrancescaBorrelli, EsterPagano, et al. Science direct. Published 2014 April 14.

repl-bcp. The Anticancer, Antioxidant and Antimicrobial Properties of the Sesquiterpene β-Caryophyllene from the Essential Oil of Aquilaria crassna [in vitro study]. Article. Saad S Dahham, Yasser M Tabana, Muhammad A Iqbal, et al. Molecules. Published 2015 June 26.

repl-ger. Geraniol, a component of plant essential oils, inhibits growth and polyamine biosynthesis in human colon cancer cells. Article. S Carnesecchi, Y Schneider, J Ceraline, et al. The Journal of pharmacology and experimental therapeutics. Published 2001 July.

repl-h. The Influence of Sesquiterpenes from Myrica rubra on the Antiproliferative and Pro-Oxidative Effects of Doxorubicin and Its Accumulation in Cancer Cells. Article. Martin Ambrož, Iva Boušová, Adam Skarka, et al. Molecules. Published 2015 August 21.

repl-api. Cell-cycle arrest at G2/M and growth inhibition by apigenin in human colon carcinoma cell lines. Abstract. W Wang, L Heideman, C S Chung, et al. Molecular carcinogenesis. Published 2000 June.

Cui_2018. IL-1β/IL-6 network in the tumor microenvironment of human colorectal cancer. Abstract. Cui G, Yuan A, Sun Z, et al. Pathology, research and practice. Online 2018 May 20.

Ma_2015. Effect of colon cancer cell-derived IL-1α on the migration and proliferation of vascular endothelial cells [in Chinese]. Abstract. Ma J, Chen Q, Gu Y, et al. Zhonghua zhong liu za zhi (Chinese journal of oncology). Published 2015 November.

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Markota_2018. Targeting interleukin-22 for cancer therapy. Full text. Markota A, Endres S, Kobolda S. Human vaccines & immunotherapeutics. Online 2018 May 17.

Simone_2014. Th17-type cytokines, IL-6 and TNF-α synergistically activate STAT3 and NF-kB to promote colorectal cancer cell growth. Full text. De Simone V, Franzè E, Ronchetti G, et al. Oncogene. 2014 September 1.

WikiMedicine_2021. Interleukin 8. Full text. WikiProjects medicine, molecular and cell biology. Wikipedia. Updated 2021 October 15.

Li_2001. Expression of Interleukin 8 and Its Receptors in Human Colon Carcinoma Cells with Different Metastatic Potentials. Full text. Li A, Varney M L, Singh R K. Clinical Cancer Research. 2001 October 1.

ping_2016. IL-1β/NF-kb signaling promotes colorectal cancer cell growth through miR-181a/PTEN axis. Abstract. ping P H, bo T F, Li L, et al. Archives of Biochemistry and Biophysics. 2016 August 15.

Cui_2018a. 3\. Conclusions [in Targeting the Tumor Microenvironment: The Protumor Effects of IL-17 Related to Cancer Type]. Full text. Cui G, Yuan A, Sun Z, et al. Pathology, research and practice. Published 2018 July.

Stolfi_2011. Involvement of interleukin-21 in the regulation of colitis-associated colon cancer. Full text. Stolfi C, Rizzo A, Franzè E, et al. The Journal of experimental medicine. Online 2011 October 24.

Hyun_2012. Role of IL-17A in the development of colitis-associated cancer. Abstract. Hyun Y S, Han D S, Lee A R, et al. Carcinogenesis. Published 2012 April.

Grivennikov_2009. IL-6 and Stat3 Are Required for Survival of Intestinal Epithelial Cells and Development of Colitis-Associated Cancer. Full text. Grivennikov S, Karin E, Terzic J, et al. Cancer cell. Online 2009 February 3.

Nallathambi_2017. Anti-Inflammatory Activity in Colon Models Is Derived from Δ9-Tetrahydrocannabinolic Acid That Interacts with Additional Compounds in Cannabis Extracts. Full text. Nallathambi R, Mazuz M, Ion A, et al. Cannabis and cannabinoid research. 2017 July 1.